import React, { useCallback, useEffect, useMemo, useRef, useState } from 'react';
import {
    Box,
    Typography,
    Paper,
    Slider,
    Button,
    Alert,
    FormControl,
    FormControlLabel,
    Switch,
    Select,
    MenuItem,
    TextField,
    IconButton,
    Tooltip,
    ButtonBase,
    Menu,
    ListItemText,
} from '@mui/material';
import {
    Play as PlayAllIcon,
    Square as StopAllIcon,
    Trash2 as DeleteIcon,
    Settings as SettingsIcon,
    Save as SaveIcon,
    X as CloseXIcon,
    Headphones as CueIcon,
    Volume2 as AudioSetupIcon,
} from 'lucide-react';
import api from '../api';
import PerformanceChannel from './PerformanceChannel';
import { PerformanceEngine } from '../utils/performanceAudio';
import { performancePanelStyles as styles, perfTokens } from '../theme';
import { MidiProvider, MidiMappable, useMidi, clearMidiConfig } from './MidiContext';
import MidiConfigMenu from './MidiConfigMenu';
import { isCueSupported, listOutputDevices, setCueDevice, setCueOutputPair } from '../utils/cueAudio';
import {
    usePerformanceSession,
    listPresetNames,
    savePreset,
    deletePreset,
    loadPresetIntoSession,
    clearPerformanceSession,
} from './usePerformanceSession';

const CHANNEL_COUNT = 4;
const MASTER_COLOR = '#35C2D4';
const MASTER_DB_MIN = -60;
const MASTER_DB_MAX = 0;
const MASTER_DB_DEFAULT = -6;
const METER_FLOOR_DB = -60;
const BPM_MIN = 20;
const BPM_MAX = 300;
const BPM_DEFAULT = 120;


const LAUNCH_QUANTIZE_OPTIONS = [
    { value: 0,     label: 'None' },
    { value: 32,    label: '8 Bars' },
    { value: 16,    label: '4 Bars' },
    { value: 8,     label: '2 Bars' },
    { value: 4,     label: '1 Bar' },
    { value: 2,     label: '1/2' },
    { value: 1,     label: '1/4' },
    { value: 0.5,   label: '1/8' },
    { value: 0.25,  label: '1/16' },
    { value: 0.125, label: '1/32' },
];
const LAUNCH_Q_DEFAULT = 4;

const dbToGain = (db) => (db <= MASTER_DB_MIN ? 0 : Math.pow(10, db / 20));
const ampToDb = (amp) => (amp <= 0 ? -Infinity : 20 * Math.log10(amp));
const formatDb = (db) => {
    if (!isFinite(db) || db <= METER_FLOOR_DB) return '−∞';
    if (Math.abs(db) < 0.05) return '0.0';
    return db.toFixed(1);
};

export default function PerformancePanel(props) {
    return (
        <MidiProvider>
            <PerformancePanelInner {...props} />
        </MidiProvider>
    );
}

function PerformancePanelInner({
    selectedModel,
    selectedUnwrappedModel,
    availableModels = [],
    baseModels = [],
    availableLoras = [],
    selectedLora = '',
    loraMultiplier = 1.0,
    onSelectModel,
    onSelectUnwrappedModel,
    onRefreshModels,
    onSelectLora,
    onLoraMultiplierChange,
    steps = 250,
    onStepsChange,
    randomSeed = true,
    seedValue = '',
    onRandomSeedChange,
    onSeedValueChange,
    onPresetLoaded,
}) {
    const { session, updateGlobal, updateChannel } = usePerformanceSession(CHANNEL_COUNT);

    const engineRef = useRef(null);
    const meterFillRef = useRef(null);
    const peakHoldRef = useRef({ db: METER_FLOOR_DB, decayedAt: performance.now() });
    const meterRafRef = useRef(null);
    const [engineReady, setEngineReady] = useState(false);
    const [masterDb, setMasterDb] = useState(session.masterDb ?? MASTER_DB_DEFAULT);
    const [bpm, setBpm] = useState(session.bpm ?? BPM_DEFAULT);
    const [bpmInput, setBpmInput] = useState(String(session.bpm ?? BPM_DEFAULT));
    const bpmInputFocusedRef = useRef(false);
    const [error, setError] = useState(null);
    const [linkAvailable, setLinkAvailable] = useState(false);
    const [linkEnabled, setLinkEnabled] = useState(session.linkEnabled ?? false);
    const [linkPeers, setLinkPeers] = useState(0);
    const [linkInstalling, setLinkInstalling] = useState(false);
    const [launchQuantum, setLaunchQuantum] = useState(session.launchQuantum ?? LAUNCH_Q_DEFAULT);
    const wasPlayingRef = useRef(false);
    const bpmOriginRef = useRef('user');
    const [peakLabelDb, setPeakLabelDb] = useState(METER_FLOOR_DB);
    const [channelStates, setChannelStates] = useState(() =>
        Array.from({ length: CHANNEL_COUNT }, () => ({ loaded: false, playing: false }))
    );
    const [injectBpm, setInjectBpm] = useState(session.injectBpm ?? true);

    // Audio output device. setSinkId requires Chromium ≥ 110 (cueSupported
    // is the runtime check). One device drives BOTH main and cue. Per-pair
    // channel routing within the device is Stage 2 — pair selections are
    // tracked here but the merger plumbing comes later.
    const cueSupported = useMemo(() => isCueSupported(), []);
    const [outputDeviceId, setOutputDeviceId] = useState(session.outputDeviceId ?? session.cueDeviceId ?? '');
    const [audioDevices, setAudioDevices] = useState([]);
    const [audioMenuAnchor, setAudioMenuAnchor] = useState(null);
    const [maxChannelCount, setMaxChannelCount] = useState(2);
    const [mainOutputPair, setMainOutputPair] = useState(session.mainOutputPair ?? 0);
    const [cueOutputPair, setCueOutputPair] = useState(session.cueOutputPair ?? 0);

    useEffect(() => { updateGlobal('outputDeviceId', outputDeviceId); }, [outputDeviceId, updateGlobal]);
    useEffect(() => {
        updateGlobal('mainOutputPair', mainOutputPair);
        engineRef.current?.setMainOutputPair?.(mainOutputPair);
    }, [mainOutputPair, updateGlobal]);
    useEffect(() => {
        updateGlobal('cueOutputPair', cueOutputPair);
        setCueOutputPair(cueOutputPair);
    }, [cueOutputPair, updateGlobal]);

    // When the chosen device changes, bind both the main engine context and
    // the (separate) cue context to it. Re-read maxChannelCount afterwards so
    // the pair selectors populate with everything the device exposes.
    useEffect(() => {
        if (!cueSupported) return;
        let cancelled = false;
        (async () => {
            const engine = engineRef.current;
            if (engine?.setOutputDevice) {
                const max = await engine.setOutputDevice(outputDeviceId);
                if (!cancelled) setMaxChannelCount(max);
            }
            await setCueDevice(outputDeviceId).catch(() => { /* logged in cueAudio */ });
        })();
        return () => { cancelled = true; };
    }, [cueSupported, outputDeviceId]);

    const refreshAudioDevices = useCallback(async () => {
        if (!cueSupported) return;
        try {
            const devices = await listOutputDevices();
            setAudioDevices(devices);
        } catch (err) {
            console.warn('[PerformancePanel] device enumeration failed', err);
        }
    }, [cueSupported]);

    const handleOpenAudioMenu = (e) => {
        setAudioMenuAnchor(e.currentTarget);
        refreshAudioDevices();
    };
    const handleCloseAudioMenu = () => setAudioMenuAnchor(null);
    const handlePickAudioDevice = (id) => {
        setOutputDeviceId(id);
        handleCloseAudioMenu();
    };

    // Restore App-level state (model, steps, seed) once on mount via the setter
    // props the panel was given. The panel doesn't own those, so this is the
    // only point at which we push session into App state. Subsequent changes
    // flow normally through the prop callbacks.
    const appStateRestoredRef = useRef(false);
    useEffect(() => {
        if (appStateRestoredRef.current) return;
        appStateRestoredRef.current = true;
        if (session.selectedModel && session.selectedModel !== selectedModel) {
            onSelectModel?.(session.selectedModel);
        }
        if (session.selectedUnwrappedModel && session.selectedUnwrappedModel !== selectedUnwrappedModel) {
            onSelectUnwrappedModel?.(session.selectedUnwrappedModel);
        }
        if (typeof session.steps === 'number' && session.steps !== steps) {
            onStepsChange?.(session.steps);
        }
        if (typeof session.randomSeed === 'boolean' && session.randomSeed !== randomSeed) {
            onRandomSeedChange?.(session.randomSeed);
        }
        if (typeof session.seedValue === 'string' && session.seedValue !== seedValue) {
            onSeedValueChange?.(session.seedValue);
        }
        // Intentionally only run on first mount.
        // eslint-disable-next-line react-hooks/exhaustive-deps
    }, []);

    // Push panel + App-level state into the session whenever any of it changes.
    useEffect(() => { updateGlobal('bpm', bpm); }, [bpm, updateGlobal]);
    useEffect(() => { updateGlobal('launchQuantum', launchQuantum); }, [launchQuantum, updateGlobal]);
    useEffect(() => { updateGlobal('masterDb', masterDb); }, [masterDb, updateGlobal]);
    useEffect(() => { updateGlobal('injectBpm', injectBpm); }, [injectBpm, updateGlobal]);
    useEffect(() => { updateGlobal('linkEnabled', linkEnabled); }, [linkEnabled, updateGlobal]);
    useEffect(() => { updateGlobal('selectedModel', selectedModel || ''); }, [selectedModel, updateGlobal]);
    useEffect(() => { updateGlobal('selectedUnwrappedModel', selectedUnwrappedModel || ''); }, [selectedUnwrappedModel, updateGlobal]);
    useEffect(() => { updateGlobal('steps', steps); }, [steps, updateGlobal]);
    useEffect(() => { updateGlobal('randomSeed', randomSeed); }, [randomSeed, updateGlobal]);
    useEffect(() => { updateGlobal('seedValue', seedValue); }, [seedValue, updateGlobal]);

    const handleChannelFormChange = useCallback((index, partial) => {
        updateChannel(index, partial);
    }, [updateChannel]);

    // ---- Preset menu state ----
    const [presetMenuAnchor, setPresetMenuAnchor] = useState(null);
    const [presetNames, setPresetNames] = useState(() => listPresetNames());
    const [saveAsName, setSaveAsName] = useState('');
    const [restoreArmed, setRestoreArmed] = useState(false);
    const restoreArmTimerRef = useRef(null);

    const refreshPresetNames = useCallback(() => {
        setPresetNames(listPresetNames());
    }, []);

    const openPresetMenu = (e) => {
        refreshPresetNames();
        setSaveAsName('');
        setRestoreArmed(false);
        setPresetMenuAnchor(e.currentTarget);
    };
    const closePresetMenu = () => {
        setPresetMenuAnchor(null);
        setRestoreArmed(false);
        if (restoreArmTimerRef.current) {
            clearTimeout(restoreArmTimerRef.current);
            restoreArmTimerRef.current = null;
        }
    };

    const handleRestoreDefaults = () => {
        if (!restoreArmed) {
            // First click arms; second click within 3 s commits. Disarms
            // automatically so the destructive path is never one accidental
            // click away.
            setRestoreArmed(true);
            if (restoreArmTimerRef.current) clearTimeout(restoreArmTimerRef.current);
            restoreArmTimerRef.current = setTimeout(() => setRestoreArmed(false), 3000);
            return;
        }
        clearPerformanceSession();
        clearMidiConfig();
        closePresetMenu();
        onPresetLoaded?.();
    };

    const handleSaveAs = () => {
        const name = saveAsName.trim();
        if (!name) return;
        savePreset(name, session);
        setSaveAsName('');
        refreshPresetNames();
    };

    const handleLoadPreset = (name) => {
        if (!loadPresetIntoSession(name)) return;
        closePresetMenu();
        // Force-remount via the App-level reset key. Same pathway as Fresh
        // Start, just with a different localStorage payload pre-loaded.
        onPresetLoaded?.();
    };

    const handleDeletePreset = (name, e) => {
        e?.stopPropagation();
        deletePreset(name);
        refreshPresetNames();
    };

    // Resolve which base model the current selection actually is. Fine-tuned
    // models carry `base_model` from training_metadata.json via /api/models;
    // legacy fine-tunes without that field fall back to the size heuristic.
    const resolvedBaseModel = (() => {
        if (!selectedModel) return null;
        if (selectedModel === 'stable-audio-open-small' || selectedModel === 'stable-audio-open-1.0') {
            return selectedModel;
        }
        const model = availableModels.find((m) => m.name === selectedModel);
        if (model?.base_model) return model.base_model;
        if (model && selectedUnwrappedModel) {
            const u = model.unwrapped_models?.find((x) => x.path === selectedUnwrappedModel);
            if (u) return (u.size_mb || 0) < 2000 ? 'stable-audio-open-small' : 'stable-audio-open-1.0';
        }
        return null;
    })();

    const isSmallModel = resolvedBaseModel === 'stable-audio-open-small';

    if (!engineRef.current) {
        engineRef.current = new PerformanceEngine(CHANNEL_COUNT);
        engineRef.current.setMasterGain(dbToGain(MASTER_DB_DEFAULT));
    }

    useEffect(() => {
        setEngineReady(true);
        const engine = engineRef.current;

        const tick = () => {
            const now = performance.now();
            const peakAmp = engine ? engine.getMasterPeak() : 0;
            const instantDb = ampToDb(peakAmp);
            const hold = peakHoldRef.current;
            const elapsed = now - hold.decayedAt;
            let displayDb = hold.db - (elapsed / 1000) * 24;
            if (instantDb > displayDb) displayDb = instantDb;
            if (displayDb < METER_FLOOR_DB) displayDb = METER_FLOOR_DB;
            hold.db = displayDb;
            hold.decayedAt = now;

            const fill = meterFillRef.current;
            if (fill) {
                const pct = ((displayDb - METER_FLOOR_DB) / -METER_FLOOR_DB) * 100;
                fill.style.height = `${Math.max(0, Math.min(100, pct))}%`;
            }
            if (Math.abs(displayDb - peakLabelDb) > 0.5) {
                setPeakLabelDb(displayDb);
            }
            meterRafRef.current = requestAnimationFrame(tick);
        };
        meterRafRef.current = requestAnimationFrame(tick);

        return () => {
            if (meterRafRef.current) cancelAnimationFrame(meterRafRef.current);
            engine.dispose();
            engineRef.current = null;
        };
    }, []);

    const handleMasterChange = (_, value) => {
        setMasterDb(value);
        engineRef.current?.setMasterGain(dbToGain(value));
    };

    useEffect(() => {
        engineRef.current?.setBpm(bpm);
    }, [bpm]);

    const handleBpmChange = (event) => {
        const raw = event.target.value;
        setBpmInput(raw);
        const parsed = Number(raw);
        if (Number.isFinite(parsed) && parsed >= BPM_MIN && parsed <= BPM_MAX) {
            bpmOriginRef.current = 'user';
            setBpm(Math.round(parsed));
        }
    };

    const handleBpmBlur = () => {
        bpmInputFocusedRef.current = false;
        const parsed = Number(bpmInput);
        if (!Number.isFinite(parsed) || bpmInput.trim() === '') {
            // Non-numeric or empty — restore the committed value.
            setBpmInput(String(bpm));
            return;
        }
        const clamped = Math.max(BPM_MIN, Math.min(BPM_MAX, Math.round(parsed)));
        bpmOriginRef.current = 'user';
        setBpm(clamped);
        setBpmInput(String(clamped));
    };

    const handleBpmFocus = () => {
        bpmInputFocusedRef.current = true;
    };

    useEffect(() => {
        if (!bpmInputFocusedRef.current) setBpmInput(String(bpm));
    }, [bpm]);

    useEffect(() => {
        api.get('/api/link/state')
            .then((r) => {
                setLinkAvailable(Boolean(r.data?.available));
                setLinkEnabled(Boolean(r.data?.enabled));
            })
            .catch(() => setLinkAvailable(false));
    }, []);


    useEffect(() => {
        if (!linkEnabled) {
            engineRef.current?.setLinkSnapshot(null);
            wasPlayingRef.current = false;
            return undefined;
        }
        let cancelled = false;
        const poll = async () => {
            const capturedAt = performance.now();
            try {
                const r = await api.get('/api/link/state');
                if (cancelled || !r.data?.enabled) return;
                const serverBpm = Math.round(r.data.bpm);
                if (serverBpm >= BPM_MIN && serverBpm <= BPM_MAX) {
                    setBpm((prev) => {
                        if (prev === serverBpm) return prev;
                        bpmOriginRef.current = 'link';
                        return serverBpm;
                    });
                }
                setLinkPeers(Number(r.data.num_peers || 0));

                const isPlaying = Boolean(r.data.is_playing);
                const beat = Number(r.data.beat) || 0;
                const bpmFloat = Number(r.data.bpm) || 120;
                engineRef.current?.setLinkSnapshot({
                    beat,
                    bpm: bpmFloat,
                    isPlaying,
                    capturedAt,
                });
                
                if (wasPlayingRef.current && !isPlaying) {
                    engineRef.current?.stopAll();
                    setChannelStates(prev => prev.map(s => ({ ...s, playing: false })));
                }
                wasPlayingRef.current = isPlaying;
            } catch {
                /* transient network blip — next tick will retry */
            }
        };
        poll();
        const timer = setInterval(poll, 500);
        return () => { cancelled = true; clearInterval(timer); };
    }, [linkEnabled]);

    useEffect(() => {
        engineRef.current?.setLaunchQuantum(launchQuantum);
    }, [launchQuantum]);

    useEffect(() => {
        if (!linkEnabled) return;
        if (bpmOriginRef.current === 'link') {
            bpmOriginRef.current = 'user';
            return;
        }
        api.post('/api/link/bpm', { bpm }).catch(() => {});
    }, [bpm, linkEnabled]);

    const handleToggleLink = useCallback(async () => {
        // First click when Link isn't installed: offer to install it.
        if (!linkAvailable) {
            const confirmed = window.confirm(
                'Ableton Link requires the LinkPython-extern package (~1–2 MB, ~30s install).\n\n'
                + 'Install it now? You\'ll only need to do this once.'
            );
            if (!confirmed) return;
            setLinkInstalling(true);
            try {
                await api.post('/api/link/install');
                setLinkAvailable(true);
                await api.post('/api/link/enable');
                setLinkEnabled(true);
            } catch (err) {
                const msg = err?.response?.data?.error || err?.response?.data?.detail || err.message || 'Install failed';
                setError(`Link install failed: ${msg}`);
            } finally {
                setLinkInstalling(false);
            }
            return;
        }

        try {
            if (linkEnabled) {
                await api.post('/api/link/disable');
                setLinkEnabled(false);
                setLinkPeers(0);
            } else {
                await api.post('/api/link/enable');
                setLinkEnabled(true);
            }
        } catch (err) {
            const status = err?.response?.status;
            const msg = err?.response?.data?.error || err.message || 'Link toggle failed';
            if (status === 503) setLinkAvailable(false);
            setError(msg);
        }
    }, [linkEnabled, linkAvailable]);

    const handlePlayAll = () => {
        engineRef.current?.playAll(true);
        setChannelStates(prev => prev.map(s => (s.loaded ? { ...s, playing: true } : s)));
    };
    const handleStopAll = () => {
        engineRef.current?.stopAll();
        setChannelStates(prev => prev.map(s => ({ ...s, playing: false })));
    };

    const applyExternalBpm = useCallback((value) => {
        const next = Math.max(BPM_MIN, Math.min(BPM_MAX, Math.round(value)));
        bpmOriginRef.current = 'user';
        setBpm(next);
    }, []);

    const midi = useMidi();
    const [midiMenuAnchor, setMidiMenuAnchor] = useState(null);

    useEffect(() => {
        if (!midi?.learnMode) return undefined;
        const onKey = (e) => {
            if (e.key === 'Escape') {
                e.preventDefault();
                midi.exitLearnMode();
            }
        };
        window.addEventListener('keydown', onKey);
        return () => window.removeEventListener('keydown', onKey);
    }, [midi?.learnMode, midi?.exitLearnMode]);

    const generateForChannel = async ({ prompt, duration, alignBars, alignBpm, batchSize = 1 }) => {
        setError(null);
        if (!selectedModel) {
            const msg = 'Pick a model first.';
            setError(msg);
            throw new Error(msg);
        }

        const trimmed = (prompt || '').trim();
        const hasExplicitBpm = /\b\d{2,3}\s*bpm\b/i.test(trimmed);
        const finalPrompt = injectBpm && !hasExplicitBpm
            ? `${trimmed}${trimmed ? ', ' : ''}${Math.round(bpm)} BPM`
            : trimmed;

        let baseSeed;
        if (randomSeed) {
            baseSeed = Math.floor(Math.random() * 0xffffffff);
        } else {
            const parsed = parseInt(seedValue, 10);
            if (Number.isNaN(parsed) || parsed < 0) {
                const msg = 'Enter a valid seed (0 or greater) or enable Random.';
                setError(msg);
                throw new Error(msg);
            }
            baseSeed = parsed;
        }

        const count = Math.max(1, Math.min(4, batchSize | 0));
        const blobs = [];
        for (let i = 0; i < count; i++) {
            // Sequential rather than parallel — the backend serves one
            // generation at a time anyway, and parallelizing would just
            // queue them server-side with no time saved. Each take gets a
            // distinct seed so the batch produces actual variations rather
            // than the same audio repeated.
            const seed = (baseSeed + i * 0x9e3779b1) >>> 0;
            // LoRA only meaningful on top of a base model (the LoRA was bound
            // to that exact base at training time; applying it to a full-FT
            // model is undefined).
            const isBaseModel = baseModels.some(m => m.name === selectedModel);
            const requestData = {
                prompt: finalPrompt,
                duration,
                cfg_scale: 7.0,
                steps,
                seed,
                model_name: selectedModel,
                batch_index: i + 1,
                batch_total: count,
                ...(selectedUnwrappedModel ? { unwrapped_model_path: selectedUnwrappedModel } : {}),
                ...(selectedLora && isBaseModel ? { lora_path: selectedLora, lora_multiplier: loraMultiplier } : {}),
                ...(alignBars && alignBpm ? { align_bars: alignBars, align_bpm: alignBpm } : {}),
            };
            const response = await api.post('/api/generate', requestData, { responseType: 'blob' });
            blobs.push(response.data);
        }
        return blobs;
    };

    const handleChannelStateChange = (index, change) => {
        setChannelStates(prev => {
            const next = [...prev];
            next[index] = { ...next[index], ...change };
            return next;
        });
    };

    const anyLoaded = channelStates.some(s => s.loaded);
    const anyPlaying = channelStates.some(s => s.playing);
    const maxDuration = isSmallModel ? 10 : 47;

    const handleMuteSoloChange = (index, change) => {
        const engine = engineRef.current;
        if (!engine) return;
        if ('mute' in change) engine.setMute(index, change.mute);
        if ('solo' in change) engine.setSolo(index, change.solo);
    };

    const channels = useMemo(() => {
        if (!engineReady || !engineRef.current) return [];
        return engineRef.current.channels;
    }, [engineReady]);

    const handleModelChange = (event) => {
        const value = event.target.value;
        if (onSelectModel) onSelectModel(value);
        if (onSelectUnwrappedModel) onSelectUnwrappedModel('');
    };

    const handleCheckpointChange = (event) => {
        if (onSelectUnwrappedModel) onSelectUnwrappedModel(String(event.target.value));
    };

    const handleDeleteFineTuned = async (modelName) => {
        const confirmed = window.confirm(
            `Delete fine-tuned model "${modelName}"? This removes the directory and all its checkpoints. This cannot be undone.`
        );
        if (!confirmed) return;
        try {
            await api.delete(`/api/models/fine-tuned/${encodeURIComponent(modelName)}`);
            if (selectedModel === modelName) {
                onSelectModel?.('');
                onSelectUnwrappedModel?.('');
            }
            onRefreshModels?.();
        } catch (err) {
            const msg = err?.response?.data?.error || err.message || 'Delete failed';
            setError(`Failed to delete "${modelName}": ${msg}`);
        }
    };

    // LoRAs share the same on-disk layout as fine-tuned models (one dir under
    // models/fine_tuned/<name>/), so the same DELETE endpoint handles both.
    const handleDeleteLora = async (loraName) => {
        const confirmed = window.confirm(
            `Delete LoRA "${loraName}"? This removes the directory and all its checkpoints. This cannot be undone.`
        );
        if (!confirmed) return;
        try {
            await api.delete(`/api/models/fine-tuned/${encodeURIComponent(loraName)}`);
            // Clear the active LoRA if it points anywhere inside the deleted dir.
            const deleted = availableLoras.find(l => l.name === loraName);
            const paths = deleted ? (deleted.all_checkpoints || [deleted.path]) : [];
            if (paths.includes(selectedLora)) onSelectLora?.('');
            onRefreshModels?.();
        } catch (err) {
            const msg = err?.response?.data?.error || err.message || 'Delete failed';
            setError(`Failed to delete LoRA "${loraName}": ${msg}`);
        }
    };

    const selectedFineTuned = selectedModel
        ? availableModels.find((m) => m.name === selectedModel)
        : null;
    const unwrappedModels = selectedFineTuned?.unwrapped_models || [];
    const checkpointValue = unwrappedModels
        .map((u) => String(u.path))
        .includes(selectedUnwrappedModel)
        ? selectedUnwrappedModel
        : '';

    return (
        <Box sx={styles.root}>
            <Paper sx={{
                display: 'flex',
                alignItems: 'center',
                gap: 1,
                px: 1.25,
                py: 0.75,
                borderRadius: 2,
                border: '1px solid',
                borderColor: 'divider',
                background: 'linear-gradient(135deg, rgba(53, 194, 212, 0.05) 0%, rgba(159, 138, 230, 0.04) 100%)',
                flexWrap: { xs: 'wrap', md: 'nowrap' },
            }}>
                {/* Link — compact rectangle, Ableton-style */}
                <Tooltip
                    title={
                        linkInstalling
                            ? 'Installing LinkPython-extern…'
                            : !linkAvailable
                                ? 'Click to install Ableton Link script'
                                : linkEnabled
                                    ? `Link on — ${linkPeers} peer${linkPeers === 1 ? '' : 's'} (click to disable)`
                                    : 'Click to sync BPM with other Link-enabled apps on this network'
                    }
                >
                    <span style={{ display: 'inline-flex', alignItems: 'center' }}>
                        <ButtonBase
                            onClick={handleToggleLink}
                            disabled={linkInstalling}
                            sx={{
                                display: 'inline-flex',
                                alignItems: 'center',
                                justifyContent: 'center',
                                fontFamily: 'inherit',
                                fontSize: perfTokens.fontSize.body,
                                fontWeight: 600,
                                px: 1,
                                minWidth: 46,
                                height: perfTokens.height.compact,
                                borderRadius: '2px',
                                // Three states matching Ableton Live's button:
                                // off → gray, on/no peers → yellow (broadcasting,
                                // alone), on/peers → teal (sync'd with at least
                                // one other app).
                                bgcolor: !linkEnabled
                                    ? '#6e6e6e'
                                    : linkPeers > 0
                                        ? MASTER_COLOR
                                        : '#F5C542',
                                color: linkEnabled ? '#000' : '#2a2a2a',
                                opacity: linkInstalling ? 0.55 : 1,
                                transition: 'background-color 120ms',
                                '&:hover': {
                                    bgcolor: !linkEnabled
                                        ? '#7d7d7d'
                                        : linkPeers > 0
                                            ? '#4DD0DE'
                                            : '#FFD54F',
                                },
                                '&.Mui-disabled': {
                                    color: linkEnabled ? '#000' : '#2a2a2a',
                                },
                            }}
                        >
                            {linkInstalling
                                ? 'installing…'
                                : linkEnabled && linkPeers > 0
                                    ? `${linkPeers} Link`
                                    : 'Link'}
                        </ButtonBase>
                    </span>
                </Tooltip>

                {/* MIDI learn toggle — same compact rectangle style as Link. */}
                <Tooltip
                    title={
                        !midi?.supported
                            ? (midi?.permissionError || 'Web MIDI is not available')
                            : midi.learnMode
                                ? 'Exit MIDI mode (Esc)'
                                : 'Enter MIDI mode — click a control then move a hardware knob/button to bind'
                    }
                >
                    <span style={{ display: 'inline-flex', alignItems: 'center' }}>
                        <ButtonBase
                            onClick={() => midi?.toggleLearnMode()}
                            disabled={!midi?.supported}
                            sx={{
                                display: 'inline-flex',
                                alignItems: 'center',
                                justifyContent: 'center',
                                fontFamily: 'inherit',
                                fontSize: perfTokens.fontSize.body,
                                fontWeight: 600,
                                px: 1,
                                minWidth: 46,
                                height: perfTokens.height.compact,
                                borderRadius: '2px',
                                bgcolor: midi?.learnMode ? '#F5C542' : '#6e6e6e',
                                color: midi?.learnMode ? '#000' : '#2a2a2a',
                                opacity: midi?.supported ? 1 : 0.45,
                                transition: 'background-color 120ms',
                                '&:hover': {
                                    bgcolor: midi?.learnMode ? '#FFD54F' : '#7d7d7d',
                                },
                                '&.Mui-disabled': {
                                    color: '#2a2a2a',
                                },
                            }}
                        >
                            MIDI
                        </ButtonBase>
                    </span>
                </Tooltip>
                <Tooltip title="MIDI settings & mappings">
                    <span style={{ display: 'inline-flex', alignItems: 'center' }}>
                        <IconButton
                            size="small"
                            onClick={(e) => setMidiMenuAnchor(e.currentTarget)}
                            sx={{ width: perfTokens.height.compact, height: perfTokens.height.compact, color: 'text.secondary' }}
                        >
                            <SettingsIcon size={14} />
                        </IconButton>
                    </span>
                </Tooltip>
                <MidiConfigMenu
                    anchorEl={midiMenuAnchor}
                    open={Boolean(midiMenuAnchor)}
                    onClose={() => setMidiMenuAnchor(null)}
                />

                <Tooltip
                    title={cueSupported
                        ? 'Audio setup — choose output device'
                        : 'Audio device selection requires Chrome/Edge (AudioContext.setSinkId). Output falls back to system default.'}
                >
                    <span style={{ display: 'inline-flex', alignItems: 'center' }}>
                        <IconButton
                            size="small"
                            onClick={handleOpenAudioMenu}
                            disabled={!cueSupported}
                            sx={{ width: perfTokens.height.compact, height: perfTokens.height.compact, color: 'text.secondary' }}
                        >
                            <AudioSetupIcon size={14} />
                        </IconButton>
                    </span>
                </Tooltip>
                <Menu
                    anchorEl={audioMenuAnchor}
                    open={Boolean(audioMenuAnchor)}
                    onClose={handleCloseAudioMenu}
                    MenuListProps={{ sx: { py: 0 } }}
                    PaperProps={{ sx: { minWidth: 280, borderRadius: 1.5 } }}
                >
                    <MenuItem disabled sx={{ opacity: 1, fontSize: perfTokens.fontSize.small, color: 'text.disabled' }}>
                        Audio Setup
                    </MenuItem>
                    <MenuItem
                        onClick={() => handlePickAudioDevice('')}
                        selected={outputDeviceId === ''}
                        sx={{ fontSize: perfTokens.fontSize.body }}
                    >
                        <ListItemText primary="System device (default)" />
                    </MenuItem>
                    {audioDevices.length === 0 && (
                        <MenuItem disabled sx={{ fontSize: perfTokens.fontSize.small }}>
                            No additional output devices detected
                        </MenuItem>
                    )}
                    {audioDevices.map(d => (
                        <MenuItem
                            key={d.deviceId}
                            onClick={() => handlePickAudioDevice(d.deviceId)}
                            selected={outputDeviceId === d.deviceId}
                            sx={{ fontSize: perfTokens.fontSize.body }}
                        >
                            <ListItemText primary={d.label || `Output (${d.deviceId.slice(0, 6)}…)`} />
                        </MenuItem>
                    ))}
                </Menu>

                <Tooltip title="Save / load presets">
                    <span style={{ display: 'inline-flex', alignItems: 'center' }}>
                        <IconButton
                            size="small"
                            onClick={openPresetMenu}
                            sx={{ width: perfTokens.height.compact, height: perfTokens.height.compact, color: 'text.secondary' }}
                        >
                            <SaveIcon size={14} />
                        </IconButton>
                    </span>
                </Tooltip>
                <Menu
                    anchorEl={presetMenuAnchor}
                    open={Boolean(presetMenuAnchor)}
                    onClose={closePresetMenu}
                    MenuListProps={{ sx: { py: 0 } }}
                    PaperProps={{
                        sx: {
                            minWidth: 240,
                            borderRadius: 1.5,
                        },
                    }}
                >
                    {/* SAVE section — type a name and click save (or press Enter) */}
                    <Box sx={{ px: 1.5, pt: 1.25, pb: 0.5 }}>
                        <Typography
                            sx={{
                                fontSize: perfTokens.fontSize.badge,
                                letterSpacing: perfTokens.letterSpacing.wide,
                                fontWeight: 700,
                                color: 'text.secondary',
                                textTransform: 'uppercase',
                            }}
                        >
                            Save
                        </Typography>
                    </Box>
                    <Box sx={{ px: 1.5, pb: 1.25, display: 'flex', alignItems: 'center', gap: 0.75 }}>
                        <TextField
                            autoFocus
                            size="small"
                            placeholder="Preset name"
                            value={saveAsName}
                            onChange={(e) => setSaveAsName(e.target.value)}
                            onKeyDown={(e) => {
                                if (e.key === 'Enter') handleSaveAs();
                                e.stopPropagation();
                            }}
                            sx={{
                                flex: 1,
                                '& .MuiOutlinedInput-root': {
                                    borderRadius: 1.5,
                                    height: perfTokens.height.compact,
                                    fontSize: perfTokens.fontSize.body,
                                },
                            }}
                        />
                        <Button
                            size="small"
                            variant="contained"
                            onClick={handleSaveAs}
                            disabled={!saveAsName.trim()}
                            sx={{
                                height: perfTokens.height.compact,
                                fontSize: perfTokens.fontSize.body,
                                fontWeight: 600,
                                letterSpacing: perfTokens.letterSpacing.wide,
                                borderRadius: 1.5,
                                minWidth: 56,
                                px: 1.25,
                            }}
                        >
                            Save
                        </Button>
                    </Box>
                    {saveAsName.trim() && presetNames.includes(saveAsName.trim()) && (
                        <Box sx={{ px: 1.5, pb: 0.75 }}>
                            <Typography
                                variant="caption"
                                color="warning.main"
                                sx={{ fontSize: perfTokens.fontSize.small }}
                            >
                                Will overwrite existing preset.
                            </Typography>
                        </Box>
                    )}

                    <Box sx={{ borderTop: '1px solid', borderColor: 'divider' }} />

                    {/* LOAD section — list of saved presets */}
                    <Box sx={{ px: 1.5, pt: 1.25, pb: 0.5 }}>
                        <Typography
                            sx={{
                                fontSize: perfTokens.fontSize.badge,
                                letterSpacing: perfTokens.letterSpacing.wide,
                                fontWeight: 700,
                                color: 'text.secondary',
                                textTransform: 'uppercase',
                            }}
                        >
                            Load
                        </Typography>
                    </Box>
                    {presetNames.length === 0 ? (
                        <Box sx={{ px: 1.5, pb: 1.25 }}>
                            <Typography
                                variant="caption"
                                color="text.disabled"
                                sx={{ fontSize: perfTokens.fontSize.small }}
                            >
                                No presets saved yet.
                            </Typography>
                        </Box>
                    ) : (
                        <Box sx={{ pb: 0.5 }}>
                            {presetNames.map((name) => (
                                <MenuItem
                                    key={name}
                                    onClick={() => handleLoadPreset(name)}
                                    sx={{
                                        display: 'flex',
                                        justifyContent: 'space-between',
                                        gap: 1,
                                        fontSize: perfTokens.fontSize.body,
                                        fontWeight: 600,
                                        letterSpacing: perfTokens.letterSpacing.wide,
                                    }}
                                >
                                    <ListItemText primary={name} primaryTypographyProps={{ sx: { fontSize: perfTokens.fontSize.body } }} />
                                    <Tooltip title="Delete preset">
                                        <IconButton
                                            size="small"
                                            onClick={(e) => handleDeletePreset(name, e)}
                                            sx={{ ml: 1, width: perfTokens.height.sub, height: perfTokens.height.sub }}
                                        >
                                            <CloseXIcon size={12} />
                                        </IconButton>
                                    </Tooltip>
                                </MenuItem>
                            ))}
                        </Box>
                    )}

                    <Box sx={{ borderTop: '1px solid', borderColor: 'divider' }} />

                    {/* Destructive: wipes session + MIDI mappings. Two-click arm
                        prevents accidental clicks; the menu auto-disarms after 3 s. */}
                    <Tooltip
                        title={restoreArmed
                            ? 'Click again within 3s to confirm — this clears all panel settings AND MIDI mappings'
                            : 'Reset panel settings and clear MIDI mappings'}
                    >
                        <MenuItem
                            onClick={handleRestoreDefaults}
                            sx={{
                                fontSize: perfTokens.fontSize.body,
                                fontWeight: 600,
                                letterSpacing: perfTokens.letterSpacing.wide,
                                color: restoreArmed ? 'error.main' : 'text.secondary',
                            }}
                        >
                            <ListItemText
                                primary={restoreArmed ? 'Click again to confirm' : 'Restore defaults'}
                                primaryTypographyProps={{ sx: { fontSize: perfTokens.fontSize.body } }}
                            />
                        </MenuItem>
                    </Tooltip>
                </Menu>

                <Tooltip placement="right" title="Launch quantization — match Live's">
                    <FormControl
                        size="small"
                        sx={{
                            minWidth: 92,
                            '& .MuiOutlinedInput-root': { borderRadius: 1.5, height: perfTokens.height.compact },
                            '& .MuiSelect-select': {
                                py: 0,
                                fontSize: perfTokens.fontSize.body,
                                fontWeight: 600,
                                letterSpacing: perfTokens.letterSpacing.wide,
                            },
                        }}
                    >
                        <Select
                            value={launchQuantum}
                            onChange={(e) => setLaunchQuantum(Number(e.target.value))}
                            renderValue={(val) => {
                                const opt = LAUNCH_QUANTIZE_OPTIONS.find((o) => o.value === val);
                                return `Q · ${opt?.label ?? 'None'}`;
                            }}
                        >
                            {LAUNCH_QUANTIZE_OPTIONS.map((opt) => (
                                <MenuItem key={opt.value} value={opt.value}>
                                    <Typography variant="body2">{opt.label}</Typography>
                                </MenuItem>
                            ))}
                        </Select>
                    </FormControl>
                </Tooltip>

                <MidiMappable
                    id="master.bpm"
                    label="Tempo (BPM)"
                    kind="continuous"
                    min={BPM_MIN}
                    max={BPM_MAX}
                    value={bpm}
                    onChange={applyExternalBpm}
                >
                    <TextField
                        size="small"
                        type="number"
                        value={bpmInput}
                        onChange={handleBpmChange}
                        onFocus={handleBpmFocus}
                        onBlur={handleBpmBlur}
                        inputProps={{ step: 1, inputMode: 'numeric', 'aria-label': 'Tempo in BPM' }}
                        InputProps={{
                            endAdornment: (
                                <Typography
                                    component="span"
                                    sx={{
                                        fontSize: perfTokens.fontSize.small,
                                        letterSpacing: perfTokens.letterSpacing.wide,
                                        color: 'text.disabled',
                                        pl: 0.5,
                                        userSelect: 'none',
                                    }}
                                >
                                    BPM
                                </Typography>
                            ),
                        }}
                        sx={{
                            width: 84,
                            '& .MuiOutlinedInput-root': { borderRadius: 1.5, pr: 1 },
                            '& input': {
                                textAlign: 'right',
                                fontVariantNumeric: 'tabular-nums',
                                fontSize: perfTokens.fontSize.body,
                                pr: 0,
                            },
                            '& input::-webkit-outer-spin-button, & input::-webkit-inner-spin-button': {
                                WebkitAppearance: 'none',
                                margin: 0,
                            },
                            '& input[type=number]': { MozAppearance: 'textfield' },
                        }}
                    />
                </MidiMappable>

                {/* Model picker + FT-checkpoint + LoRA pickers now live in the
                    bottom bar so the top strip stays just BPM + transport. */}

                <MidiMappable id="master.playAll" label="Play All" kind="trigger" onChange={handlePlayAll}>
                    <Button
                        size="small"
                        variant="outlined"
                        startIcon={<PlayAllIcon size={14} />}
                        onClick={handlePlayAll}
                        disabled={!anyLoaded}
                        sx={styles.masterBtn(MASTER_COLOR, 'play')}
                    >
                        Play All
                    </Button>
                </MidiMappable>
                <MidiMappable id="master.stopAll" label="Stop All" kind="trigger" onChange={handleStopAll}>
                    <Button
                        size="small"
                        variant="outlined"
                        startIcon={<StopAllIcon size={14} />}
                        onClick={handleStopAll}
                        disabled={!anyPlaying}
                        sx={styles.masterBtn(MASTER_COLOR, 'stop')}
                    >
                        Stop All
                    </Button>
                </MidiMappable>
            </Paper>

            {error && (
                <Alert severity="warning" sx={styles.errorAlert} onClose={() => setError(null)}>
                    {error}
                </Alert>
            )}

            <Box sx={styles.channelsRow}>
                <Box sx={styles.channelsGrid}>
                    {channels.map((strip, i) => (
                        <PerformanceChannel
                            key={i}
                            index={i}
                            strip={strip}
                            engine={engineRef.current}
                            playing={channelStates[i]?.playing || false}
                            onGenerate={generateForChannel}
                            canGenerate={Boolean(selectedModel)}
                            onMuteSoloChange={handleMuteSoloChange}
                            onStateChange={handleChannelStateChange}
                            onFormStateChange={handleChannelFormChange}
                            initialFormState={session.channels[i]}
                            maxDuration={maxDuration}
                            bpm={bpm}
                        />
                    ))}
                </Box>

                <Box sx={styles.masterStrip(MASTER_COLOR)}>
                    <Box sx={styles.masterHeader(MASTER_COLOR)}>
                        <Box sx={styles.masterBadge(MASTER_COLOR)}>MASTER</Box>
                    </Box>

                    <Box sx={styles.masterFaderWrap}>
                        <Box sx={styles.masterMeterTrack}>
                            <Box ref={meterFillRef} sx={styles.masterMeterFill(MASTER_COLOR)} />
                            <Box sx={styles.masterMeterSegments} />
                        </Box>
                        <MidiMappable
                            id="master.fader"
                            label="Master Fader"
                            kind="continuous"
                            min={MASTER_DB_MIN}
                            max={MASTER_DB_MAX}
                            value={masterDb}
                            onChange={(v) => handleMasterChange(null, v)}
                            sx={{ flex: 1, alignSelf: 'stretch' }}
                        >
                            <Slider
                                orientation="vertical"
                                value={masterDb}
                                onChange={handleMasterChange}
                                min={MASTER_DB_MIN}
                                max={MASTER_DB_MAX}
                                step={0.1}
                                sx={styles.masterFader(MASTER_COLOR)}
                            />
                        </MidiMappable>
                    </Box>

                    <Box sx={styles.masterReadouts}>
                        <Typography variant="caption" sx={styles.masterValue}>
                            dBFS {formatDb(masterDb)}
                        </Typography>
                        <Typography variant="caption" sx={styles.masterPeakValue}>
                            pk {formatDb(peakLabelDb)}
                        </Typography>
                    </Box>

                    {/* Main / Cue output channel pair selection. Pairs are
                        derived from the current device's maxChannelCount.
                        Stage 1: selections are stored but routing still goes
                        through the stereo destination — channel-pair routing
                        via ChannelMergerNode lands in Stage 2. */}
                    {(() => {
                        const pairCount = Math.max(1, Math.floor(maxChannelCount / 2));
                        const pairs = Array.from({ length: pairCount }, (_, i) => ({
                            value: i,
                            label: `${i * 2 + 1}–${i * 2 + 2}`,
                        }));
                        const labelSx = {
                            fontSize: perfTokens.fontSize.small,
                            letterSpacing: perfTokens.letterSpacing.wide,
                            color: 'text.disabled',
                            display: 'block',
                            mb: 0.25,
                        };
                        const selectSx = {
                            width: '100%',
                            '& .MuiOutlinedInput-root': { borderRadius: 1.5 },
                            '& .MuiSelect-select': {
                                fontSize: perfTokens.fontSize.body,
                                py: 0.5,
                            },
                        };
                        return (
                            <Box sx={{ display: 'flex', flexDirection: 'column', gap: 1, mt: 0.5 }}>
                                <Box>
                                    <Typography component="span" sx={labelSx}>MAIN OUT</Typography>
                                    <FormControl size="small" sx={selectSx}>
                                        <Select
                                            value={Math.min(mainOutputPair, pairCount - 1)}
                                            onChange={(e) => setMainOutputPair(Number(e.target.value))}
                                        >
                                            {pairs.map(p => (
                                                <MenuItem key={p.value} value={p.value}>
                                                    <Typography variant="body2">Ch {p.label}</Typography>
                                                </MenuItem>
                                            ))}
                                        </Select>
                                    </FormControl>
                                </Box>
                                <Box>
                                    <Typography component="span" sx={labelSx}>CUE OUT</Typography>
                                    <FormControl size="small" sx={selectSx}>
                                        <Select
                                            value={Math.min(cueOutputPair, pairCount - 1)}
                                            onChange={(e) => setCueOutputPair(Number(e.target.value))}
                                        >
                                            {pairs.map(p => (
                                                <MenuItem key={p.value} value={p.value}>
                                                    <Typography variant="body2">Ch {p.label}</Typography>
                                                </MenuItem>
                                            ))}
                                        </Select>
                                    </FormControl>
                                </Box>
                            </Box>
                        );
                    })()}
                </Box>
            </Box>

            <Paper sx={{
                display: 'flex',
                alignItems: 'center',
                gap: 2.5,
                px: 1.5,
                py: 0.75,
                mt: 1,
                borderRadius: 2,
                border: '1px solid',
                borderColor: 'divider',
                background: 'linear-gradient(135deg, rgba(53, 194, 212, 0.04) 0%, rgba(159, 138, 230, 0.03) 100%)',
                flexWrap: { xs: 'wrap', md: 'nowrap' },
            }}>
                {/* Model + artifact pickers — moved here from the top row so the
                    primary strip stays just BPM + transport. Each is gated so
                    they only appear when relevant. */}
                <FormControl size="small" sx={{
                    width: 120,
                    '& .MuiOutlinedInput-root': { borderRadius: 1.5 },
                    '& .MuiSelect-select': {
                        fontSize: perfTokens.fontSize.body,
                        overflow: 'hidden',
                        textOverflow: 'ellipsis',
                        whiteSpace: 'nowrap',
                    },
                }}>
                    <Select
                        value={selectedModel || ''}
                        onChange={handleModelChange}
                        displayEmpty
                        renderValue={(value) => {
                            if (!value) return <em style={{ opacity: 0.6 }}>Model</em>;
                            const SHORT = {
                                'stable-audio-open-1.0': 'SAO Full',
                                'stable-audio-open-small': 'SAO Small',
                            };
                            if (SHORT[value]) return SHORT[value];
                            const base = baseModels.find((m) => m.name === value);
                            if (base) return base.displayName || base.name;
                            return value;
                        }}
                    >
                        {baseModels.length > 0 && (
                            <MenuItem disabled>
                                <Typography variant="caption" color="textSecondary">
                                    ── Base Models ──
                                </Typography>
                            </MenuItem>
                        )}
                        {baseModels.map((model) => (
                            <MenuItem
                                key={model.name}
                                value={String(model.name)}
                                disabled={!model.downloaded}
                            >
                                <Typography variant="body2">
                                    {model.displayName || model.name}
                                </Typography>
                            </MenuItem>
                        ))}
                        {availableModels.length > 0 && (
                            <MenuItem disabled>
                                <Typography variant="caption" color="textSecondary">
                                    ── Fine-tuned Models ──
                                </Typography>
                            </MenuItem>
                        )}
                        {availableModels.map((model) => (
                            <MenuItem
                                key={model.name}
                                value={String(model.name)}
                                sx={{ display: 'flex', justifyContent: 'space-between', gap: 1, pr: 0.5 }}
                            >
                                <Typography variant="body2" sx={{ flex: 1, overflow: 'hidden', textOverflow: 'ellipsis' }}>
                                    {model.name}
                                </Typography>
                                <Tooltip title="Delete fine-tuned model">
                                    <IconButton
                                        size="small"
                                        onMouseDown={(e) => { e.stopPropagation(); e.preventDefault(); }}
                                        onClick={(e) => {
                                            e.stopPropagation();
                                            e.preventDefault();
                                            handleDeleteFineTuned(model.name);
                                        }}
                                        sx={{
                                            color: 'text.disabled',
                                            '&:hover': { color: 'error.main', bgcolor: 'action.hover' },
                                        }}
                                    >
                                        <DeleteIcon size={14} />
                                    </IconButton>
                                </Tooltip>
                            </MenuItem>
                        ))}
                    </Select>
                </FormControl>

                {unwrappedModels.length > 0 && (
                    <FormControl size="small" sx={{
                        width: 120,
                        '& .MuiOutlinedInput-root': { borderRadius: 1.5 },
                        '& .MuiSelect-select': {
                            fontSize: perfTokens.fontSize.body,
                            overflow: 'hidden',
                            textOverflow: 'ellipsis',
                            whiteSpace: 'nowrap',
                        },
                    }}>
                        <Select
                            value={checkpointValue}
                            onChange={handleCheckpointChange}
                            displayEmpty
                            renderValue={(value) => {
                                if (!value) return <em style={{ opacity: 0.6 }}>Ckpt</em>;
                                const found = unwrappedModels.find((u) => String(u.path) === value);
                                return found ? found.name : value;
                            }}
                        >
                            {unwrappedModels.map((unwrapped, index) => (
                                <MenuItem key={index} value={String(unwrapped.path)}>
                                    <Box>
                                        <Typography variant="body2">{unwrapped.name}</Typography>
                                        {unwrapped.size_mb && (
                                            <Typography variant="caption" color="textSecondary">
                                                {unwrapped.size_mb} MB
                                            </Typography>
                                        )}
                                    </Box>
                                </MenuItem>
                            ))}
                        </Select>
                    </FormControl>
                )}

                {/* LoRA + its checkpoint sub-picker — always rendered (disabled
                    when irrelevant) so the bar layout doesn't shift as the user
                    picks. */}
                {(() => {
                    const isBaseModel = baseModels.some(m => m.name === selectedModel);
                    const compatibleLoras = isBaseModel
                        ? availableLoras.filter(l => l.base_model === selectedModel)
                        : [];
                    const currentLora = compatibleLoras.find(
                        l => l.path === selectedLora ||
                             (l.all_checkpoints || []).includes(selectedLora)
                    );
                    const currentLoraName = currentLora?.name || '';
                    const parseCheckpointLabel = (filepath) => {
                        const name = (filepath || '').split('/').pop() || filepath || '';
                        const m = name.match(/epoch=(\d+)-step=(\d+)/);
                        if (m) return `Ep ${m[1]} · ${m[2]}`;
                        return name.replace(/\.ckpt$/i, '');
                    };
                    const loraDisabled = compatibleLoras.length === 0;
                    const ckptCount = currentLora?.all_checkpoints?.length ?? 0;
                    const ckptDisabled = !currentLora || ckptCount <= 1;
                    return (
                        <>
                            <FormControl size="small" disabled={loraDisabled} sx={{
                                width: 120,
                                '& .MuiOutlinedInput-root': { borderRadius: 1.5 },
                                '& .MuiSelect-select': {
                                    fontSize: perfTokens.fontSize.body,
                                    overflow: 'hidden',
                                    textOverflow: 'ellipsis',
                                    whiteSpace: 'nowrap',
                                },
                            }}>
                                <Select
                                    value={currentLoraName}
                                    onChange={(e) => {
                                        const name = e.target.value;
                                        if (!name) { onSelectLora?.(''); return; }
                                        const lora = compatibleLoras.find(l => l.name === name);
                                        onSelectLora?.(lora?.path || '');
                                    }}
                                    displayEmpty
                                    renderValue={(value) => {
                                        if (!value) return <em style={{ opacity: 0.6 }}>No LoRA</em>;
                                        return value;
                                    }}
                                >
                                    <MenuItem value="">
                                        <em>No LoRA</em>
                                    </MenuItem>
                                    {compatibleLoras.map((lora) => (
                                        <MenuItem
                                            key={lora.name}
                                            value={lora.name}
                                            sx={{ display: 'flex', justifyContent: 'space-between', gap: 1, pr: 0.5 }}
                                        >
                                            <Box sx={{ flex: 1, minWidth: 0 }}>
                                                <Typography variant="body2">{lora.name}</Typography>
                                                <Typography variant="caption" color="textSecondary">
                                                    rank={lora.rank}
                                                    {lora.all_checkpoints?.length > 1
                                                        ? ` · ${lora.all_checkpoints.length} ckpts`
                                                        : ''}
                                                </Typography>
                                            </Box>
                                            <Tooltip title="Delete LoRA">
                                                <IconButton
                                                    size="small"
                                                    onMouseDown={(e) => { e.stopPropagation(); e.preventDefault(); }}
                                                    onClick={(e) => {
                                                        e.stopPropagation();
                                                        e.preventDefault();
                                                        handleDeleteLora(lora.name);
                                                    }}
                                                    sx={{
                                                        color: 'text.disabled',
                                                        '&:hover': { color: 'error.main', bgcolor: 'action.hover' },
                                                    }}
                                                >
                                                    <DeleteIcon size={14} />
                                                </IconButton>
                                            </Tooltip>
                                        </MenuItem>
                                    ))}
                                </Select>
                            </FormControl>

                            <FormControl size="small" disabled={ckptDisabled} sx={{
                                width: 100,
                                '& .MuiOutlinedInput-root': { borderRadius: 1.5 },
                                '& .MuiSelect-select': {
                                    fontSize: perfTokens.fontSize.body,
                                    overflow: 'hidden',
                                    textOverflow: 'ellipsis',
                                    whiteSpace: 'nowrap',
                                },
                            }}>
                                <Select
                                    value={ckptDisabled ? '' : (selectedLora || currentLora?.path || '')}
                                    onChange={(e) => onSelectLora?.(String(e.target.value))}
                                    displayEmpty
                                    renderValue={(value) => {
                                        if (!value) return <em style={{ opacity: 0.6 }}>Ckpt</em>;
                                        return parseCheckpointLabel(value);
                                    }}
                                >
                                    {(currentLora?.all_checkpoints || []).map((ckpt, i, arr) => (
                                        <MenuItem key={ckpt} value={ckpt}>
                                            <Typography variant="body2">
                                                {parseCheckpointLabel(ckpt)}
                                                {i === arr.length - 1 ? ' (latest)' : ''}
                                            </Typography>
                                        </MenuItem>
                                    ))}
                                </Select>
                            </FormControl>
                        </>
                    );
                })()}

                <Box sx={{ display: 'flex', alignItems: 'center', gap: 0.75 }}>
                    <Typography
                        component="span"
                        sx={{
                            fontSize: perfTokens.fontSize.small,
                            letterSpacing: perfTokens.letterSpacing.wide,
                            color: 'text.disabled',
                        }}
                    >
                        STEPS
                    </Typography>
                    <Tooltip
                        placement="right"
                        title={
                            isSmallModel
                                ? 'Locked at 8 steps for the distilled small model'
                                : 'Diffusion steps per generation (more = higher quality, slower)'
                        }
                    >
                        <FormControl
                            size="small"
                            sx={{
                                width: 64,
                                '& .MuiOutlinedInput-root': { borderRadius: 1.5 },
                                '& .MuiSelect-select': { fontSize: perfTokens.fontSize.body },
                            }}
                        >
                            <Select
                                value={isSmallModel ? 8 : steps}
                                onChange={(e) => onStepsChange?.(Number(e.target.value))}
                                disabled={isSmallModel}
                                renderValue={(value) => `${value}`}
                            >
                                {isSmallModel && (
                                    <MenuItem value={8}>
                                        <Typography variant="body2">8 (locked)</Typography>
                                    </MenuItem>
                                )}
                                {[50, 100, 150, 200, 250].map((n) => (
                                    <MenuItem key={n} value={n}>
                                        <Typography variant="body2">{n}</Typography>
                                    </MenuItem>
                                ))}
                            </Select>
                        </FormControl>
                    </Tooltip>
                </Box>

                <Box sx={{ display: 'flex', alignItems: 'center', gap: 0.5 }}>
                    <Typography
                        component="span"
                        sx={{
                            fontSize: perfTokens.fontSize.small,
                            letterSpacing: perfTokens.letterSpacing.wide,
                            color: 'text.disabled',
                        }}
                    >
                        SEED
                    </Typography>
                    <FormControlLabel
                        sx={{ mr: 0, ml: 0.25 }}
                        control={
                            <Switch
                                size="small"
                                checked={randomSeed}
                                onChange={(e) => onRandomSeedChange?.(e.target.checked)}
                            />
                        }
                        label={
                            <Typography component="span" sx={{ fontSize: perfTokens.fontSize.small }}>
                                Random
                            </Typography>
                        }
                    />
                    <TextField
                        size="small"
                        type="number"
                        placeholder="42"
                        value={seedValue}
                        onChange={(e) => onSeedValueChange?.(e.target.value)}
                        disabled={randomSeed}
                        inputProps={{ min: 0, max: 4294967295, step: 1 }}
                        sx={{
                            width: 78,
                            '& .MuiOutlinedInput-root': { borderRadius: 1.5 },
                            '& input': {
                                fontVariantNumeric: 'tabular-nums',
                                fontSize: perfTokens.fontSize.body,
                            },
                        }}
                    />
                </Box>

                <Tooltip
                    placement="right"
                    title="When on, the master BPM is injected to each prompt automatically (turn off if doing free-tempo or multi-tempo prompts)."
                >
                    <Box sx={{ display: 'flex', alignItems: 'center', gap: 0.5 }}>
                        <Typography
                            component="span"
                            sx={{
                                fontSize: perfTokens.fontSize.small,
                                letterSpacing: perfTokens.letterSpacing.wide,
                                color: 'text.disabled',
                            }}
                        >
                            AUTO BPM
                        </Typography>
                        <Switch
                            size="small"
                            checked={injectBpm}
                            onChange={(e) => setInjectBpm(e.target.checked)}
                        />
                    </Box>
                </Tooltip>
            </Paper>
        </Box>
    );
}