import React, { useState, useCallback } from 'react';
import { motion, AnimatePresence } from 'framer-motion';
import { Upload, FileText, AlertTriangle, CheckCircle, Loader2, Info, ChevronRight, Sparkles, Download, ShieldCheck } from 'lucide-react';
import { uploadReverseAuditDocument, uploadGapReportDocument, exportGapReportFromFile, AuditMode } from '../../api/client';
import toast from 'react-hot-toast';

export const ReverseAuditPanel: React.FC = () => {
    const [isDragging, setIsDragging] = useState(false);
    const [file, setFile] = useState<File | null>(null);
    const [programName, setProgramName] = useState('');
    const [auditMode, setAuditMode] = useState<AuditMode>('pro');
    const [isAuditing, setIsAuditing] = useState(false);
    const [isExporting, setIsExporting] = useState<'pdf' | 'docx' | null>(null);
    const [auditResult, setAuditResult] = useState<any>(null);

    const onDragOver = (e: React.DragEvent) => {
        e.preventDefault();
        setIsDragging(true);
    };

    const onDragLeave = () => {
        setIsDragging(false);
    };

    const onDrop = useCallback((e: React.DragEvent) => {
        e.preventDefault();
        setIsDragging(false);
        if (e.dataTransfer.files && e.dataTransfer.files.length > 0) {
            setFile(e.dataTransfer.files[0]);
        }
    }, []);

    const handleFileChange = (e: React.ChangeEvent<HTMLInputElement>) => {
        if (e.target.files && e.target.files.length > 0) {
            setFile(e.target.files[0]);
        }
    };

    const handleAudit = async () => {
        if (!file) {
            toast.error("Proszę wybrać plik do audytu.");
            return;
        }
        if (auditMode === 'pro' && !programName.trim()) {
            toast.error("Tryb Pro wymaga nazwy programu / naboru.");
            return;
        }

        setIsAuditing(true);
        setAuditResult(null);

        try {
            if (auditMode === 'pro') {
                const data = await uploadGapReportDocument(file, programName.trim());
                setAuditResult(data);
            } else {
                const data = await uploadReverseAuditDocument(file, programName || undefined);
                setAuditResult({ ...data, mode: 'llm' });
            }
            toast.success(auditMode === 'pro' ? "Audyt deterministyczny zakończony!" : "Audyt LLM zakończony!");
        } catch (error: any) {
            toast.error(error.response?.data?.detail || "Wystąpił błąd podczas audytu.");
        } finally {
            setIsAuditing(false);
        }
    };

    const handleExport = async (format: 'pdf' | 'docx') => {
        if (!file || !programName.trim()) {
            toast.error("Wymagany plik i nazwa programu do eksportu.");
            return;
        }
        setIsExporting(format);
        try {
            await exportGapReportFromFile(file, programName.trim(), format);
            toast.success(`Pobrano raport ${format.toUpperCase()}`);
        } catch (error: any) {
            toast.error(error.response?.data?.detail || "Eksport nie powiódł się.");
        } finally {
            setIsExporting(null);
        }
    };

    const renderSeverityIcon = (severity: string) => {
        switch (severity.toLowerCase()) {
            case 'critical': return <AlertTriangle size={20} color="var(--accent-red)" />;
            case 'high': return <AlertTriangle size={20} color="var(--accent-orange)" />;
            case 'medium': return <Info size={20} color="var(--accent-blue)" />;
            default: return <Info size={20} color="var(--text-secondary)" />;
        }
    };

    return (
        <div style={{ display: 'flex', flexDirection: 'column', gap: '2rem', padding: '1rem' }}>
            <div style={{ background: 'var(--bg-secondary)', padding: '2rem', borderRadius: '12px', border: '1px solid var(--border-color)' }}>
                <h2 style={{ display: 'flex', alignItems: 'center', gap: '0.75rem', marginBottom: '1.5rem', color: 'var(--text-primary)' }}>
                    <Sparkles size={24} color="var(--accent-blue)" /> Reverse Audit (Weryfikacja Wniosku)
                </h2>
                <p style={{ color: 'var(--text-secondary)', marginBottom: '1.5rem', lineHeight: '1.6' }}>
                    Prześlij gotowy wniosek (PDF, DOCX lub TXT). <strong>Tryb Pro</strong> używa deterministycznego audytu luk (snapshot gap audit) bez LLM.
                    <strong> Tryb LLM</strong> uruchamia GraphRAG + Regulation Engine z wieloperspektywiczną analizą.
                </p>

                <div style={{ display: 'flex', gap: '0.75rem', marginBottom: '1.5rem', flexWrap: 'wrap' }}>
                    <button
                        type="button"
                        onClick={() => setAuditMode('pro')}
                        style={{
                            padding: '0.5rem 1rem', borderRadius: '8px', border: '1px solid var(--border-color)',
                            background: auditMode === 'pro' ? 'rgba(56,189,248,0.15)' : 'var(--bg-primary)',
                            color: auditMode === 'pro' ? 'var(--accent-blue)' : 'var(--text-secondary)',
                            cursor: 'pointer', display: 'flex', alignItems: 'center', gap: '0.4rem', fontWeight: 600,
                        }}
                    >
                        <ShieldCheck size={16} /> Pro (deterministyczny)
                    </button>
                    <button
                        type="button"
                        onClick={() => setAuditMode('llm')}
                        style={{
                            padding: '0.5rem 1rem', borderRadius: '8px', border: '1px solid var(--border-color)',
                            background: auditMode === 'llm' ? 'rgba(167,139,250,0.15)' : 'var(--bg-primary)',
                            color: auditMode === 'llm' ? '#a78bfa' : 'var(--text-secondary)',
                            cursor: 'pointer', display: 'flex', alignItems: 'center', gap: '0.4rem', fontWeight: 600,
                        }}
                    >
                        <Sparkles size={16} /> LLM (GraphRAG)
                    </button>
                </div>

                <div style={{ display: 'flex', flexDirection: 'column', gap: '1rem', marginBottom: '2rem' }}>
                    <label style={{ color: 'var(--text-secondary)', fontSize: '0.9rem' }}>
                        Docelowy program / nabór {auditMode === 'pro' ? '(wymagany w trybie Pro)' : '(opcjonalnie)'}:
                    </label>
                    <input 
                        type="text" 
                        placeholder="np. Ścieżka SMART, Horizon Europe, Kredyt Ekologiczny..." 
                        value={programName}
                        onChange={(e) => setProgramName(e.target.value)}
                        style={{
                            width: '100%', padding: '0.75rem 1rem', borderRadius: '8px',
                            border: '1px solid var(--border-color)', background: 'var(--bg-primary)',
                            color: 'var(--text-primary)', outline: 'none'
                        }}
                    />
                </div>

                <div 
                    onDragOver={onDragOver}
                    onDragLeave={onDragLeave}
                    onDrop={onDrop}
                    style={{
                        border: `2px dashed ${isDragging ? 'var(--accent-blue)' : 'var(--border-color)'}`,
                        borderRadius: '12px', padding: '3rem 2rem', textAlign: 'center',
                        background: isDragging ? 'rgba(56, 189, 248, 0.05)' : 'var(--bg-primary)',
                        transition: 'all 0.2s ease', cursor: 'pointer', marginBottom: '2rem'
                    }}
                    onClick={() => document.getElementById('audit-file-upload')?.click()}
                >
                    <input 
                        id="audit-file-upload" 
                        type="file" 
                        accept=".pdf,.docx,.txt" 
                        style={{ display: 'none' }} 
                        onChange={handleFileChange}
                    />
                    <Upload size={40} color={isDragging ? 'var(--accent-blue)' : 'var(--text-secondary)'} style={{ margin: '0 auto 1rem auto' }} />
                    <div style={{ fontSize: '1.1rem', color: 'var(--text-primary)', marginBottom: '0.5rem' }}>
                        {file ? file.name : 'Przeciągnij plik tutaj lub kliknij, aby wybrać'}
                    </div>
                    <div style={{ fontSize: '0.9rem', color: 'var(--text-secondary)' }}>Obsługiwane formaty: PDF, DOCX, TXT</div>
                </div>

                <div style={{ display: 'flex', justifyContent: 'flex-end', gap: '0.75rem', flexWrap: 'wrap' }}>
                    {auditMode === 'pro' && auditResult && (
                        <>
                            <button
                                onClick={() => handleExport('pdf')}
                                disabled={!!isExporting}
                                style={{
                                    background: 'transparent', color: 'var(--text-primary)', border: '1px solid var(--border-color)',
                                    padding: '0.75rem 1.25rem', borderRadius: '8px', cursor: 'pointer',
                                    display: 'flex', alignItems: 'center', gap: '0.5rem',
                                }}
                            >
                                {isExporting === 'pdf' ? <Loader2 size={16} className="animate-spin" /> : <Download size={16} />}
                                PDF
                            </button>
                            <button
                                onClick={() => handleExport('docx')}
                                disabled={!!isExporting}
                                style={{
                                    background: 'transparent', color: 'var(--text-primary)', border: '1px solid var(--border-color)',
                                    padding: '0.75rem 1.25rem', borderRadius: '8px', cursor: 'pointer',
                                    display: 'flex', alignItems: 'center', gap: '0.5rem',
                                }}
                            >
                                {isExporting === 'docx' ? <Loader2 size={16} className="animate-spin" /> : <Download size={16} />}
                                DOCX
                            </button>
                        </>
                    )}
                    <button 
                        onClick={handleAudit} 
                        disabled={!file || isAuditing}
                        style={{
                            background: auditMode === 'pro' ? 'var(--accent-blue)' : '#7c3aed', color: 'white', border: 'none',
                            padding: '0.75rem 2rem', borderRadius: '8px', fontWeight: '500',
                            cursor: (!file || isAuditing) ? 'not-allowed' : 'pointer',
                            display: 'flex', alignItems: 'center', gap: '0.5rem',
                            opacity: (!file || isAuditing) ? 0.6 : 1
                        }}
                    >
                        {isAuditing ? <Loader2 size={18} className="animate-spin" /> : <FileText size={18} />}
                        {isAuditing ? 'Analizowanie...' : auditMode === 'pro' ? 'Audyt Pro (gap-report)' : 'Audyt LLM'}
                    </button>
                </div>
            </div>

            <AnimatePresence>
                {auditResult && (
                    <motion.div 
                        initial={{ opacity: 0, y: 20 }}
                        animate={{ opacity: 1, y: 0 }}
                        exit={{ opacity: 0, height: 0 }}
                        style={{ background: 'var(--bg-secondary)', padding: '2rem', borderRadius: '12px', border: '1px solid var(--border-color)' }}
                    >
                        <h3 style={{ fontSize: '1.2rem', marginBottom: '1rem', color: 'var(--text-primary)', display: 'flex', alignItems: 'center', gap: '0.5rem' }}>
                            Wyniki Audytu 
                            {auditResult.mode === 'pro' && (
                                <span style={{ fontSize: '0.75rem', background: 'rgba(56,189,248,0.15)', color: 'var(--accent-blue)', padding: '2px 8px', borderRadius: '4px' }}>PRO</span>
                            )}
                            {auditResult.is_approved ? <CheckCircle color="var(--accent-green)" size={20} /> : <AlertTriangle color="var(--accent-red)" size={20} />}
                        </h3>
                        
                        <div style={{ display: 'grid', gridTemplateColumns: '1fr 1fr', gap: '1rem', marginBottom: '2rem' }}>
                            <div style={{ background: 'var(--bg-primary)', padding: '1rem', borderRadius: '8px', border: '1px solid var(--border-color)' }}>
                                <div style={{ fontSize: '0.9rem', color: 'var(--text-secondary)', marginBottom: '0.2rem' }}>Ocena ogólna (Score)</div>
                                <div style={{ fontSize: '1.5rem', fontWeight: 'bold', color: auditResult.overall_score > 75 ? 'var(--accent-green)' : (auditResult.overall_score > 50 ? 'var(--accent-orange)' : 'var(--accent-red)') }}>
                                    {auditResult.overall_score} / 100
                                </div>
                            </div>
                            <div style={{ background: 'var(--bg-primary)', padding: '1rem', borderRadius: '8px', border: '1px solid var(--border-color)' }}>
                                <div style={{ fontSize: '0.9rem', color: 'var(--text-secondary)', marginBottom: '0.2rem' }}>Wymaga weryfikacji eksperta</div>
                                <div style={{ fontSize: '1.1rem', fontWeight: 'bold', color: auditResult.human_review_required ? 'var(--accent-orange)' : 'var(--accent-green)' }}>
                                    {auditResult.human_review_required ? 'TAK' : 'NIE'}
                                </div>
                            </div>
                        </div>

                        {auditResult.summary && (
                            <p style={{ color: 'var(--text-secondary)', marginBottom: '1.5rem', fontSize: '0.95rem' }}>{auditResult.summary}</p>
                        )}

                        <h4 style={{ marginBottom: '1rem', color: 'var(--text-primary)' }}>Wykryte luki i błędy ({auditResult.issues?.length || 0}):</h4>
                        
                        <div style={{ display: 'flex', flexDirection: 'column', gap: '1rem' }}>
                            {auditResult.issues?.length === 0 ? (
                                <div style={{ padding: '1.5rem', textAlign: 'center', color: 'var(--text-secondary)', background: 'rgba(16, 185, 129, 0.05)', borderRadius: '8px', border: '1px dashed var(--accent-green)' }}>
                                    <CheckCircle size={32} color="var(--accent-green)" style={{ margin: '0 auto 0.5rem auto' }} />
                                    Nie znaleziono żadnych luk względem regulaminu!
                                </div>
                            ) : (
                                auditResult.issues?.map((issue: any, idx: number) => (
                                    <div key={idx} style={{ background: 'var(--bg-primary)', padding: '1.25rem', borderRadius: '8px', borderLeft: `4px solid ${issue.severity === 'critical' ? 'var(--accent-red)' : (issue.severity === 'high' ? 'var(--accent-orange)' : 'var(--accent-blue)')}` }}>
                                        <div style={{ display: 'flex', alignItems: 'flex-start', gap: '0.75rem' }}>
                                            {renderSeverityIcon(issue.severity)}
                                            <div style={{ flex: 1 }}>
                                                <div style={{ fontWeight: '600', color: 'var(--text-primary)', marginBottom: '0.5rem' }}>
                                                    {issue.category} <span style={{ fontSize: '0.8rem', fontWeight: 'normal', color: 'var(--text-secondary)', marginLeft: '0.5rem' }}>[{issue.perspective}]</span>
                                                </div>
                                                <div style={{ color: 'var(--text-primary)', marginBottom: '0.75rem', lineHeight: '1.5' }}>
                                                    {issue.message}
                                                </div>
                                                {issue.rule_citation && (
                                                    <div style={{ fontSize: '0.85rem', color: 'var(--text-secondary)', background: 'var(--bg-secondary)', padding: '0.5rem', borderRadius: '4px', marginBottom: '0.75rem', fontStyle: 'italic' }}>
                                                        <strong>Cytat z regulaminu:</strong> {issue.rule_citation}
                                                    </div>
                                                )}
                                                {issue.recommendation && (
                                                    <div style={{ fontSize: '0.9rem', color: 'var(--accent-green)', display: 'flex', gap: '0.5rem', alignItems: 'flex-start' }}>
                                                        <ChevronRight size={16} style={{ marginTop: '0.1rem', flexShrink: 0 }} />
                                                        <span><strong>Rekomendacja:</strong> {issue.recommendation}</span>
                                                    </div>
                                                )}
                                            </div>
                                        </div>
                                    </div>
                                ))
                            )}
                        </div>
                    </motion.div>
                )}
            </AnimatePresence>
        </div>
    );
};