"""Tab 4 — Process Simulator: downstream piping transient simulation.

Pump → Snubber → Control Valve → Pipe → Atmosphere/Tank.
Supports manual CSV pump LUT upload and auto-generation from cycle2mdot.
"""

from __future__ import annotations

import math
import os
import gradio as gr
import numpy as np
import plotly.graph_objects as go
from plotly.subplots import make_subplots

from murphy_unified.process_sim.engine import (
    Simulation,
    SIM_MODE_VALVE,
    SIM_MODE_FILL,
    SIM_MODES,
    MAX_STEPS,
)
from murphy_unified.process_sim.pump_lut import (
    PumpLUT,
    generate_pump_lut,
    _load_csv,
    _find_col,
    DATA_DIR,
    GENERATED_DIR,
)
from murphy_unified.theme import (
    ACCENT,
    ACCENT2,
    WARN,
    DANGER,
    TEXT,
    TEXT_BRIGHT,
    SURFACE,
    SURFACE2,
)
from murphy_unified.tab_help import tagline_html

try:
    import anthropic
    HAS_ANTHROPIC = True
except ImportError:
    HAS_ANTHROPIC = False


# ── Parameter definitions ────────────────────────────────────────────────────

PARAM_DEFS = [
    ("pump_T_out", 60.0, "Pump outlet T (K)", "Pump"),
    ("pump_cpm_max", 500.0, "Pump max speed (cpm)", "Pump"),
    ("snub_V_L", 0.5, "Snubber volume (L)", "Snubber"),
    ("snub_P0_bar", 1.01325, "Snubber init P (bar)", "Snubber"),
    ("snub_T0_K", 60.0, "Snubber init T (K)", "Snubber"),
    ("v2_cv", 0.25, "Valve 2 max Cv", "Control Valve 2"),
    ("v2_pct", 50.0, "Valve 2 opening (%)", "Control Valve 2"),
    ("p2_id_in", 0.4645, "Pipe 2 ID (inch)", "Pipe 2"),
    ("p2_len_ft", 10.0, "Pipe 2 length (ft)", "Pipe 2"),
    ("tank_V_L", 450.0, "Tank volume (L)", "Tank (Fill mode)"),
    ("tank_P0_bar", 1.01325, "Tank init P (bar)", "Tank (Fill mode)"),
    ("tank_dT_K", 20.0, "Tank T offset above pump (K)", "Tank (Fill mode)"),
    ("roughness_mm", 0.015, "Pipe roughness (mm)", "General"),
    ("P_atm_bar", 1.01325, "Atmospheric P (bar)", "General"),
    ("motor_pct", 50.0, "Motor speed (%)", "Simulation"),
    ("dt", 0.001, "Time step (s)", "Simulation"),
    ("duration", 10.0, "Duration (s)", "Simulation"),
]

PARAM_KEYS = [d[0] for d in PARAM_DEFS]


# ── Helpers ──────────────────────────────────────────────────────────────────

def _file_path(file):
    """Handle both gradio 4 (obj with .name) and gradio 5+ (str path)."""
    if file is None:
        return None
    return getattr(file, "name", file)


def _load_pump_lut(file):
    fpath = _file_path(file)
    if fpath is None:
        return None, "No pump LUT loaded — upload a CSV."
    try:
        lut = PumpLUT.from_csv(fpath)
        return lut, lut.summary()
    except Exception as e:
        return None, f"Error loading pump CSV: {e}"


def _load_profile_csv(file):
    fpath = _file_path(file)
    if fpath is None:
        return None, None, None, "No profile file loaded."
    try:
        headers, hlower, data = _load_csv(fpath)
    except Exception as e:
        return None, None, None, f"CSV error: {e}"

    t_col = _find_col(hlower, ["time", "seconds", "t_s", "t(s)"])
    m_col = _find_col(hlower, ["motor", "speed", "rpm", "pump"])
    v_col = _find_col(hlower, ["valve", "v2", "opening", "cv_pct"])

    if t_col is None:
        return None, None, None, f"No time column. Headers: {headers}"
    if m_col is None and v_col is None:
        return None, None, None, f"No motor or valve columns. Headers: {headers}"

    t_data = data[t_col]
    m_data = data.get(m_col) if m_col else None
    v_data = data.get(v_col) if v_col else None

    msg_parts = [f"Loaded {len(t_data)} rows (t={t_data[0]:.1f}-{t_data[-1]:.1f} s)"]
    if m_data is not None:
        msg_parts.append(f"Motor: {m_data.min():.0f}-{m_data.max():.0f}%")
    if v_data is not None:
        msg_parts.append(f"Valve: {v_data.min():.0f}-{v_data.max():.0f}%")
    return t_data, m_data, v_data, "\n".join(msg_parts)


def _load_actual_csv(file):
    fpath = _file_path(file)
    if fpath is None:
        return None, "No actual data loaded."
    try:
        headers, hlower, data = _load_csv(fpath)
    except Exception as e:
        return None, f"CSV error: {e}"

    t_col = _find_col(hlower, ["time", "seconds", "t_s", "t(s)"])
    p_col = _find_col(hlower, ["pt130", "pressure", "p_snub", "snubber", "psi", "bar"])

    if t_col is None or p_col is None:
        return None, f"Need time + pressure cols. Headers: {headers}"

    actual = {
        "time": data[t_col],
        "pressure": data[p_col],
        "filename": os.path.basename(fpath),
    }
    n = len(actual["time"])
    msg = (
        f"Loaded {actual['filename']} ({n} points, "
        f"{actual['time'][0]:.1f}-{actual['time'][-1]:.1f} s)"
    )
    return actual, msg


# ── Plotting ─────────────────────────────────────────────────────────────────

def _build_plotly_figure(results, actual_data=None):
    """Build 3x2 Plotly subplot grid matching the HF Space layout."""
    fill_mode = results.get("sim_mode") == SIM_MODE_FILL and "P_tank_bar" in results
    t = results["time"]

    fig = make_subplots(
        rows=3, cols=2,
        subplot_titles=[
            "Snubber Pressure", "Pump Mass Flow Rate",
            "Outlet Flow Rate", "Tank Pressure" if fill_mode else "Net Flow into Snubber",
            "Motor Speed & Valve Opening", "Pump Discharge Temperature",
        ],
        vertical_spacing=0.08,
        horizontal_spacing=0.08,
    )

    # (1,1) Snubber Pressure
    fig.add_trace(go.Scatter(
        x=t, y=results["P_snub_bar"], mode="lines",
        name="Simulated", line=dict(color=ACCENT, width=1),
    ), row=1, col=1)
    if actual_data is not None:
        fig.add_trace(go.Scatter(
            x=actual_data["time"], y=actual_data["pressure"], mode="lines",
            name="Actual (PT130)", line=dict(color=DANGER, width=1.5),
        ), row=1, col=1)
    fig.update_yaxes(title_text="Pressure (bar)", row=1, col=1)

    # (1,2) Pump Mass Flow
    fig.add_trace(go.Scatter(
        x=t, y=results["mdot_pump"], mode="lines",
        name="Pump flow", line=dict(color=DANGER, width=1), showlegend=False,
    ), row=1, col=2)
    fig.update_yaxes(title_text="Flow (kg/min)", row=1, col=2)

    # (2,1) Outlet Flow
    fig.add_trace(go.Scatter(
        x=t, y=results["mdot_out"], mode="lines",
        name="Outlet flow", line=dict(color=ACCENT2, width=1), showlegend=False,
    ), row=2, col=1)
    fig.update_yaxes(title_text="Flow (kg/min)", row=2, col=1)

    # (2,2) Net Flow or Tank Pressure
    if fill_mode:
        fig.add_trace(go.Scatter(
            x=t, y=results["P_tank_bar"], mode="lines",
            name="Tank P", line=dict(color=WARN, width=1), showlegend=False,
        ), row=2, col=2)
        fig.update_yaxes(title_text="Pressure (bar)", row=2, col=2)
    else:
        net = results["mdot_net"]
        fig.add_trace(go.Scatter(
            x=t, y=net, mode="lines",
            name="Net flow", line=dict(color=ACCENT, width=1), showlegend=False,
        ), row=2, col=2)
        fig.update_yaxes(title_text="Net Flow (kg/min)", row=2, col=2)

    # (3,1) Motor Speed & Valve Opening
    fig.add_trace(go.Scatter(
        x=t, y=results["motor_pct"], mode="lines",
        name="Motor Speed", line=dict(color=TEXT_BRIGHT, width=1),
    ), row=3, col=1)
    fig.add_trace(go.Scatter(
        x=t, y=results["valve2_pct"], mode="lines",
        name="Valve 2", line=dict(color=WARN, width=1, dash="dash"),
    ), row=3, col=1)
    fig.update_yaxes(title_text="Percentage (%)", range=[-5, 105], row=3, col=1)

    # (3,2) Pump Discharge Temperature
    fig.add_trace(go.Scatter(
        x=t, y=results["T_pump_K"], mode="lines",
        name="T pump", line=dict(color=DANGER, width=1), showlegend=False,
    ), row=3, col=2)
    fig.update_yaxes(title_text="Temperature (K)", row=3, col=2)

    # Apply time axis labels to bottom row
    fig.update_xaxes(title_text="Time (s)", row=3, col=1)
    fig.update_xaxes(title_text="Time (s)", row=3, col=2)

    fig.update_layout(
        height=750,
        template="plotly_dark",
        paper_bgcolor=SURFACE,
        plot_bgcolor=SURFACE2,
        font=dict(family="JetBrains Mono, monospace", color=TEXT),
        legend=dict(orientation="h", yanchor="bottom", y=1.02, xanchor="right", x=1),
        margin=dict(t=40, b=40, l=50, r=20),
    )

    return fig


# ── Results summary ──────────────────────────────────────────────────────────

def _results_summary(results, pump_lut):
    pump_info = "Pump LUT loaded" if pump_lut is not None else "No pump LUT (zero flow)"
    r = results
    mode = r.get("sim_mode", SIM_MODE_VALVE)
    lines = [
        pump_info,
        f"Mode: {mode}",
        f"Final snubber P = {r['P_snub_bar'][-1]:.4f} bar",
        f"Peak snubber P  = {max(r['P_snub_bar']):.2f} bar",
        f"Peak pump flow  = {max(r['mdot_pump']):.4f} kg/min",
        f"Final outlet    = {r['mdot_out'][-1]:.4f} kg/min",
        f"T_pump range    = {min(r['T_pump_K']):.1f} - {max(r['T_pump_K']):.1f} K",
    ]
    if "P_tank_bar" in r:
        lines.append(
            f"Tank T (fixed)  = {r.get('T_tank_K', 0):.1f} K (= pump T_dis + offset)"
        )
        lines.append(
            f"Final tank P    = {r['P_tank_bar'][-1]:.4f} bar (peak {max(r['P_tank_bar']):.2f})"
        )
        lines.append(
            f"Tank mass       = {r['m_tank_kg'][0]:.3f} → {r['m_tank_kg'][-1]:.3f} kg "
            f"(Δ {r['m_tank_kg'][-1] - r['m_tank_kg'][0]:+.3f} kg)"
        )
    return "\n".join(lines)


def _comparison_metrics(results, actual):
    if results is None or actual is None:
        return ""
    sim_interp = np.interp(actual["time"], results["time"], results["P_snub_bar"])
    diff = sim_interp - actual["pressure"]
    rmse = float(np.sqrt(np.mean(diff**2)))
    mae = float(np.mean(np.abs(diff)))
    max_err = float(np.max(np.abs(diff)))
    bias = float(np.mean(diff))
    corr = (
        float(np.corrcoef(sim_interp, actual["pressure"])[0, 1]) if len(diff) > 2 else float("nan")
    )
    return (
        f"=== Simulated vs Actual (PT130) ===\n"
        f"Data points:   {len(actual['time'])}\n"
        f"Time range:    {actual['time'][0]:.1f} - {actual['time'][-1]:.1f} s\n"
        f"RMSE:          {rmse:.2f} bar\n"
        f"MAE:           {mae:.2f} bar\n"
        f"Max |error|:   {max_err:.2f} bar\n"
        f"Mean bias:     {bias:+.2f} bar (sim-actual)\n"
        f"Correlation:   {corr:.4f}\n"
        f"Sim peak:      {max(results['P_snub_bar']):.1f} bar\n"
        f"Actual peak:   {max(actual['pressure']):.1f} bar"
    )


# ── Claude inline chat ───────────────────────────────────────────────────────

_SYSTEM_PROMPT = (
    "You are an expert cryogenic process engineer and simulation analyst. "
    "You are embedded in a simulation tool for a cryogenic hydrogen piping system "
    "with: reciprocating pump (2-D LUT) -> snubber volume -> control valve -> "
    "vent pipe -> atmosphere or tank.\n\n"
    "The simulation uses Euler integration with a single state variable:\n"
    "  m_snub (mass in snubber)\n"
    "Pressure is computed from density via a 1-D CoolProp LUT at fixed T.\n\n"
    "Provide concise, actionable engineering insights. Use numbers."
)


def _build_context(params_dict, pump_lut, results, actual, profile_state):
    lines = ["=== SIMULATION CONFIGURATION ==="]
    for key, val in params_dict.items():
        lines.append(f"  {key}: {val}")
    if pump_lut is not None:
        lines.append(f"\n=== PUMP LUT ===\n  {pump_lut.summary()}")
    if results is not None:
        lines.append("\n=== RESULTS SUMMARY ===")
        lines.append(f"  Mode: {results.get('sim_mode', SIM_MODE_VALVE)}")
        lines.append(
            f"  Snubber P: min={min(results['P_snub_bar']):.2f}, "
            f"max={max(results['P_snub_bar']):.2f}, "
            f"final={results['P_snub_bar'][-1]:.2f} bar"
        )
        lines.append(f"  Pump flow max={max(results['mdot_pump']):.3f} kg/min")
        lines.append(
            f"  Outlet flow max={max(results['mdot_out']):.3f}, "
            f"final={results['mdot_out'][-1]:.3f} kg/min"
        )
        if "P_tank_bar" in results:
            lines.append(
                f"  Tank P: final={results['P_tank_bar'][-1]:.2f}, "
                f"peak={max(results['P_tank_bar']):.2f} bar"
            )
        t_samples = np.arange(0, results["time"][-1] + 0.01, 1.0)
        P_samples = np.interp(t_samples, results["time"], results["P_snub_bar"])
        lines.append("\n  Snubber P at 1 Hz (t_s, P_bar):")
        for ts, ps in zip(t_samples, P_samples):
            lines.append(f"    {ts:.0f}, {ps:.2f}")
    if actual is not None:
        lines.append(f"\n=== ACTUAL DATA ({actual.get('filename', '')}) ===")
        lines.append(
            f"  Pressure range: {min(actual['pressure']):.2f} - "
            f"{max(actual['pressure']):.2f} bar"
        )
    return "\n".join(lines)


def _chat_with_claude(user_message, history, pump_lut_state, results_state,
                       actual_data_state, profile_state, *param_values):
    # history is list of (user_msg, bot_msg) tuples for Gradio 6.x Chatbot
    if not HAS_ANTHROPIC:
        history = history + [(user_message, "anthropic SDK not installed.")]
        return history, ""

    api_key = os.environ.get("ANTHROPIC_API_KEY", "").strip()
    if not api_key:
        history = history + [(user_message, "ANTHROPIC_API_KEY not set.")]
        return history, ""

    params_dict = {k: v for k, v in zip(PARAM_KEYS, param_values)}
    context = _build_context(
        params_dict, pump_lut_state, results_state, actual_data_state, profile_state
    )
    system = f"{_SYSTEM_PROMPT}\n\n{context}"

    # Convert tuple history to API messages format
    api_messages = []
    for user_msg, bot_msg in history:
        if user_msg:
            api_messages.append({"role": "user", "content": user_msg})
        if bot_msg:
            api_messages.append({"role": "assistant", "content": bot_msg})
    api_messages.append({"role": "user", "content": user_message})

    try:
        client = anthropic.Anthropic(api_key=api_key)
        response = client.messages.create(
            model="claude-sonnet-4-6",
            max_tokens=2048,
            system=system,
            messages=api_messages,
        )
        reply = response.content[0].text
    except Exception as e:
        reply = f"Error: {e}"

    history = history + [(user_message, reply)]
    return history, ""


def _auto_analyze(history, pump_lut_state, results_state, actual_data_state,
                   profile_state, *param_values):
    if results_state is None:
        history = history + [(None, "Run a simulation first, then click Auto-Analyze.")]
        return history, ""
    prompt = (
        "Analyze the simulation results. Compare simulated vs actual snubber "
        "pressure if actual data is loaded. Comment on pump flow vs outlet flow "
        "balance and pressure buildup. Identify key differences, possible causes, "
        "and suggest parameter tuning. Be specific and quantitative."
    )
    return _chat_with_claude(
        prompt, history, pump_lut_state, results_state,
        actual_data_state, profile_state, *param_values,
    )


# ── Simulation runner ────────────────────────────────────────────────────────

def _run_simulation(
    pump_lut_state, profile_enabled, profile_state, actual_data_state,
    pulsation_enabled, sim_mode, *param_values, progress=gr.Progress(),
):
    params = {}
    try:
        for key, val in zip(PARAM_KEYS, param_values):
            params[key] = float(val)
    except (ValueError, TypeError) as e:
        raise gr.Error(f"Invalid parameter value: {e}")

    if params["dt"] <= 0 or params["duration"] <= 0:
        raise gr.Error("Time step and duration must be > 0")

    n_steps = int(params["duration"] / params["dt"])
    if n_steps > MAX_STEPS:
        raise gr.Error(
            f"Simulation would require {n_steps:,} steps (cap: {MAX_STEPS:,}). "
            f"Increase dt or decrease duration."
        )

    params["pulsation"] = bool(pulsation_enabled)
    params["pump_lut"] = pump_lut_state
    params["sim_mode"] = sim_mode or SIM_MODE_VALVE
    prof = profile_state or {}
    params["use_profiles"] = bool(profile_enabled) and prof.get("times") is not None
    params["profile_times"] = prof.get("times") if params["use_profiles"] else None
    params["profile_motor"] = prof.get("motor") if params["use_profiles"] else None
    params["profile_valve2"] = prof.get("valve") if params["use_profiles"] else None

    def cb(frac):
        progress(frac, desc="Building LUT..." if frac < 0.05 else "Integrating...")

    sim = Simulation(params)
    results = sim.run(cb=cb)

    fig = _build_plotly_figure(results, actual_data_state)
    summary = _results_summary(results, pump_lut_state)
    compare = _comparison_metrics(results, actual_data_state)
    return fig, summary, compare, results


# ── LUT generation runner ────────────────────────────────────────────────────

def _run_generate_lut(engine, spd_min, spd_max, spd_step, prs_min, prs_max,
                       prs_step, progress=gr.Progress()):
    total = (
        len(np.arange(spd_min, spd_max + spd_step * 0.5, spd_step))
        * len(np.arange(prs_min, prs_max + prs_step * 0.5, prs_step))
    )

    engine_map = {"Lightspeed": "lightspeed", "Euler": "euler", "General-ODE": "general_ode"}
    eng = engine_map.get(engine, "lightspeed")

    def cb(frac):
        progress(frac, desc=f"Generating LUT ({int(frac*total)}/{total} points)...")

    lut = generate_pump_lut(
        engine=eng,
        speed_range=(spd_min, spd_max, spd_step),
        pressure_range=(prs_min, prs_max, prs_step),
        progress_cb=cb,
        save=True,
    )
    return lut, lut.summary()


# ── Sweep payload ingestion ─────────────────────────────────────────────────

_REQUIRED_SWEEP_KEYS = (
    "x_vals", "y_vals", "z_mdot_kgpm", "z_temp_K", "axis_x", "axis_y",
)


def _ingest_sweep_payload(payload):
    """Build a PumpLUT from a sweep bridge payload; save CSV; return UI updates.

    Raises
    ------
    gr.Error
        If payload is None, missing required keys, or has axes other than
        Pexit_barg × speed_f.
    """
    if payload is None:
        raise gr.Error(
            "No compatible sweep data — run a 2D sweep on "
            "Pexit_barg vs speed_f first."
        )

    missing = [k for k in _REQUIRED_SWEEP_KEYS if k not in payload]
    if missing:
        raise gr.Error(
            f"Sweep payload is missing required keys: {', '.join(missing)}. "
            "This usually means the Sweep tab produced an incompatible "
            "payload — please re-run the 2D Pexit_barg × speed_f sweep."
        )

    axes = {payload["axis_x"], payload["axis_y"]}
    if axes != {"Pexit_barg", "speed_f"}:
        raise gr.Error(
            "Process Sim ingest requires a 2D sweep on exactly "
            f"(Pexit_barg, speed_f). Got ({payload['axis_x']}, "
            f"{payload['axis_y']}). Run the 2D Pexit_barg vs speed_f sweep."
        )

    try:
        lut = PumpLUT.from_sweep_grid(
            x_vals=payload["x_vals"],
            y_vals=payload["y_vals"],
            z_mdot_kgpm=payload["z_mdot_kgpm"],
            z_temp_K=payload["z_temp_K"],
            axis_x=payload["axis_x"],
            axis_y=payload["axis_y"],
        )
    except (ValueError, TypeError) as e:
        raise gr.Error(f"Could not build pump LUT from sweep payload: {e}")

    # Save CSV to data/generated/ with a unique timestamp. Tolerate a
    # read-only filesystem (e.g., restricted HF Space deploy) — the LUT is
    # still usable in-session even if the CSV side-effect fails.
    import datetime as _dt
    now = _dt.datetime.now()
    ts = now.strftime("%Y-%m-%d_%H%M%S")
    hw = payload.get("hw", "unknown")
    csv_path = GENERATED_DIR / f"lut_{ts}_sweep_{hw}.csv"
    save_note = f"Saved: {csv_path.name}"
    try:
        GENERATED_DIR.mkdir(parents=True, exist_ok=True)
        lut.save(str(csv_path))
    except (OSError, PermissionError) as e:
        save_note = f"Save skipped ({e.__class__.__name__})"

    # Status + provenance strings.
    n_speeds = len(lut.speeds)
    n_press = len(lut.pressures)
    status = (
        f"Loaded from sweep ({n_speeds}x{n_press}, hw={hw}, "
        f"{payload.get('timestamp', '')})\n"
        f"{lut.summary()}\n"
        f"{save_note}"
    )
    provenance = (
        f"Source: 2D sweep (axes: Pexit_barg x speed_f)\n"
        f"Grid: {n_speeds} speeds x {n_press} pressures\n"
        f"Hardware: {hw}\n"
        f"Timestamp: {payload.get('timestamp', '')}\n"
        f"{save_note}"
    )
    mode_update = gr.update(value="From Sweep")

    return lut, status, mode_update, provenance


# ── Tab builder ──────────────────────────────────────────────────────────────

def build_process_sim_tab():
    """Build the Process Sim tab. Must be called inside a gr.TabItem context.

    Returns
    -------
    dict
        Handles used by app.py to wire cross-tab events:
          * ``pump_lut_state``
          * ``pump_lut_status``
          * ``lut_mode``
          * ``sweep_provenance``
          * ``ingest_fn`` (callable: bridge payload → (lut, status, mode_update, provenance))
    """

    gr.HTML(tagline_html("process_sim"))

    pump_lut_state = gr.State(None)
    results_state = gr.State(None)
    actual_data_state = gr.State(None)
    profile_state = gr.State({"times": None, "motor": None, "valve": None})

    with gr.Row():
        # ── Left column: inputs ──
        with gr.Column(scale=1):
            with gr.Accordion("LUT Source", open=True):
                lut_mode = gr.Radio(
                    choices=["Upload CSV", "Auto-Generate from Engine", "From Sweep"],
                    value="Upload CSV",
                    label="Pump LUT Source",
                )

                # CSV upload mode
                with gr.Group(visible=True) as csv_group:
                    pump_file = gr.File(
                        label="Pump CSV (motor_pct, back_pressure_bar (absolute), mdot_kgs, [T_discharge_K])",
                        file_types=[".csv"],
                    )
                    pump_lut_status = gr.Textbox(
                        label="Pump LUT status",
                        value="No pump LUT loaded — upload a CSV.",
                        interactive=False, lines=2,
                    )

                # Auto-generate mode
                with gr.Group(visible=False) as gen_group:
                    gen_engine = gr.Dropdown(
                        choices=["Lightspeed", "Euler", "General-ODE"],
                        value="Lightspeed",
                        label="Engine",
                    )
                    gen_btn = gr.Button("Generate LUT", variant="secondary")
                    gen_status = gr.Textbox(
                        label="Generation status", value="", interactive=False, lines=2,
                    )
                    with gr.Accordion("Override Grid", open=False):
                        spd_min = gr.Number(label="Speed min (%)", value=10)
                        spd_max = gr.Number(label="Speed max (%)", value=100)
                        spd_step = gr.Number(label="Speed step (%)", value=10)
                        prs_min = gr.Number(label="Pressure min (bar)", value=0)
                        prs_max = gr.Number(label="Pressure max (bar)", value=900)
                        prs_step = gr.Number(label="Pressure step (bar)", value=50)

                # From-sweep mode (read-only provenance panel)
                with gr.Group(visible=False) as sweep_group:
                    sweep_provenance = gr.Textbox(
                        label="Sweep provenance",
                        value="No sweep data ingested yet. Run a 2D sweep on "
                              "(Pexit_barg, speed_f) and click 'Send to Process Sim'.",
                        interactive=False, lines=5,
                    )

            sim_mode_radio = gr.Radio(
                choices=SIM_MODES,
                value=SIM_MODE_VALVE,
                label="Simulation Mode",
            )

            # Parameter accordions
            param_inputs = {}
            sections = {}
            for key, default, label, section in PARAM_DEFS:
                sections.setdefault(section, []).append((key, default, label))
            for sec_name, items in sections.items():
                open_default = "Tank" not in sec_name
                with gr.Accordion(sec_name, open=open_default):
                    for key, default, label in items:
                        param_inputs[key] = gr.Number(
                            label=label, value=default, precision=None,
                        )

            with gr.Accordion("Profiles", open=False):
                profile_enabled = gr.Checkbox(
                    label="Enable time-varying profiles", value=False,
                )
                profile_file = gr.File(
                    label="Profile CSV (time, motor_speed, valve_opening)",
                    file_types=[".csv"],
                )
                profile_status = gr.Textbox(
                    label="Profile status", value="No profile loaded",
                    interactive=False, lines=2,
                )

            with gr.Accordion("Actual Data Overlay", open=False):
                actual_file = gr.File(
                    label="Actual data CSV (time + PT130 pressure)",
                    file_types=[".csv"],
                )
                actual_status = gr.Textbox(
                    label="Actual data status", value="No data loaded",
                    interactive=False, lines=2,
                )

            pulsation_cb = gr.Checkbox(
                label="Enable pump pulsation (half-sine on LUT avg)", value=True,
            )
            run_btn = gr.Button("Run Simulation", variant="primary")

        # ── Right column: outputs ──
        with gr.Column(scale=2):
            plot_out = gr.Plot(label="Simulation Results")
            summary_box = gr.Textbox(
                label="Summary", value="", interactive=False, lines=7,
            )
            compare_box = gr.Textbox(
                label="Comparison metrics", value="", interactive=False, lines=10,
            )

            gr.Markdown("### Claude AI Analysis")
            chatbot = gr.Chatbot(label="Claude", height=300)
            chat_input = gr.Textbox(
                label="Message",
                placeholder="Ask about the simulation results...",
            )
            with gr.Row():
                send_btn = gr.Button("Send")
                auto_btn = gr.Button("Auto-Analyze")
                clear_chat_btn = gr.Button("Clear")

    # ── Event wiring ─────────────────────────────────────────────────────

    param_component_list = [param_inputs[k] for k in PARAM_KEYS]

    # LUT mode toggle
    def _toggle_lut_mode(mode):
        return (
            gr.update(visible=(mode == "Upload CSV")),
            gr.update(visible=(mode == "Auto-Generate from Engine")),
            gr.update(visible=(mode == "From Sweep")),
        )

    lut_mode.change(
        fn=_toggle_lut_mode,
        inputs=[lut_mode],
        outputs=[csv_group, gen_group, sweep_group],
        api_name=False,
    )

    # CSV upload
    pump_file.change(
        fn=_load_pump_lut,
        inputs=[pump_file],
        outputs=[pump_lut_state, pump_lut_status],
        api_name=False,
    )

    # Auto-generate
    gen_btn.click(
        fn=_run_generate_lut,
        inputs=[gen_engine, spd_min, spd_max, spd_step, prs_min, prs_max, prs_step],
        outputs=[pump_lut_state, gen_status],
        api_name=False,
    )

    # Profiles
    def _on_profile_upload(file):
        t, m, v, msg = _load_profile_csv(file)
        state = {"times": t, "motor": m, "valve": v}
        if t is not None and len(t) > 0:
            new_duration = float(math.ceil(float(t[-1])))
            msg = msg + f"\nDuration set to {new_duration:.0f} s"
            return state, msg, gr.update(value=True), gr.update(value=new_duration)
        return state, msg, gr.update(), gr.update()

    profile_file.change(
        fn=_on_profile_upload,
        inputs=[profile_file],
        outputs=[profile_state, profile_status, profile_enabled, param_inputs["duration"]],
        api_name=False,
    )

    # Actual data
    actual_file.change(
        fn=_load_actual_csv,
        inputs=[actual_file],
        outputs=[actual_data_state, actual_status],
        api_name=False,
    )

    # Run simulation
    run_btn.click(
        fn=_run_simulation,
        inputs=[
            pump_lut_state, profile_enabled, profile_state, actual_data_state,
            pulsation_cb, sim_mode_radio, *param_component_list,
        ],
        outputs=[plot_out, summary_box, compare_box, results_state],
        api_name=False,
    )

    # Chat
    chat_inputs = [
        chat_input, chatbot, pump_lut_state, results_state,
        actual_data_state, profile_state, *param_component_list,
    ]
    send_btn.click(fn=_chat_with_claude, inputs=chat_inputs, outputs=[chatbot, chat_input], api_name=False)
    chat_input.submit(fn=_chat_with_claude, inputs=chat_inputs, outputs=[chatbot, chat_input], api_name=False)

    auto_inputs = [chatbot, pump_lut_state, results_state, actual_data_state, profile_state, *param_component_list]
    auto_btn.click(fn=_auto_analyze, inputs=auto_inputs, outputs=[chatbot, chat_input], api_name=False)

    clear_chat_btn.click(fn=lambda: ([], ""), inputs=[], outputs=[chatbot, chat_input], api_name=False)

    return {
        "pump_lut_state": pump_lut_state,
        "pump_lut_status": pump_lut_status,
        "lut_mode": lut_mode,
        "sweep_provenance": sweep_provenance,
        "ingest_fn": _ingest_sweep_payload,
    }