import React, { useState, useRef, useEffect } from 'react';
import { motion, AnimatePresence } from 'framer-motion';
import { Bot, X, Send, AlertCircle, ChevronDown, Pin, Sparkles, Trash2 } from 'lucide-react';
import { getProjectChatHistory, sendProjectChatMessage, getProjectSections, updateProjectSection, clearProjectChatHistory } from '../../api/client';
import toast from 'react-hot-toast';

interface ProjectChatPanelProps {
    projectId: string;
    projectName?: string;
    activeSectionId?: string;
    activeSectionTitle?: string;
}

interface ChatMessage {
    id: string;
    role: 'user' | 'assistant';
    content: string;
    created_at?: string;
    isError?: boolean;
    originalInput?: string;
}

const ProjectChatPanel: React.FC<ProjectChatPanelProps> = ({ projectId, projectName, activeSectionId, activeSectionTitle }) => {
    const [isOpen, setIsOpen] = useState(false);
    const [isPinned, setIsPinned] = useState(false);
    const [messages, setMessages] = useState<ChatMessage[]>([]);
    const [input, setInput] = useState('');
    const [isLoading, setIsLoading] = useState(false);
    const messagesEndRef = useRef<HTMLDivElement>(null);

    const scrollToBottom = () => {
        messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' });
    };

    useEffect(() => {
        const fetchHistory = async () => {
            try {
                const history = await getProjectChatHistory(projectId);
                if (history && history.length > 0) {
                    setMessages(history);
                }
            } catch (err) {
                console.error("Failed to load chat history", err);
            }
        };
        if (isOpen || isPinned) {
            fetchHistory();
        }
    }, [projectId, isOpen, isPinned]);

    useEffect(() => {
        scrollToBottom();
    }, [messages, isOpen, isLoading]);

    useEffect(() => {
        const handleCmdJ = (e: KeyboardEvent) => {
            if ((e.ctrlKey || e.metaKey) && e.key.toLowerCase() === 'j') {
                e.preventDefault();
                setIsOpen(prev => !prev);
            }
        };
        window.addEventListener('keydown', handleCmdJ);
        return () => window.removeEventListener('keydown', handleCmdJ);
    }, []);

    const handleClearHistory = async () => {
        if (!window.confirm("Czy na pewno chcesz trwale usunąć historię rozmów z asystentem dla tego projektu?")) {
            return;
        }
        setIsLoading(true);
        try {
            await clearProjectChatHistory(projectId);
            setMessages([]);
            toast.success("Historia została pomyślnie wyczyszczona.");
        } catch (error) {
            console.error(error);
            toast.error("Nie udało się usunąć historii czatu.");
        } finally {
            setIsLoading(false);
        }
    };

    const handleSendRef = useRef<any>(null);

    useEffect(() => {
        const handleOpenChat = (e: any) => {
            setIsOpen(true);
            const { prefillMessage, autoSend } = e.detail || {};
            if (prefillMessage) {
                if (autoSend) {
                    setTimeout(() => {
                        if (handleSendRef.current) handleSendRef.current(prefillMessage);
                    }, 50);
                } else {
                    setInput(prefillMessage);
                }
            }
        };
        window.addEventListener('open-project-chat', handleOpenChat);
        return () => window.removeEventListener('open-project-chat', handleOpenChat);
    }, []);

    const handleApplySuggestion = async (text: string, mode: 'insert' | 'replace', sectionTarget?: string) => {
        if (mode === 'insert') {
            if (sectionTarget && sectionTarget !== 'Aktywna sekcja') {
                 window.dispatchEvent(new CustomEvent('navigate-to-section', {
                    detail: { sectionType: sectionTarget }
                }));
            } else {
                 window.dispatchEvent(new CustomEvent('switch-to-sections-tab'));
            }
            
            // Wait a bit for the SectionEditor to mount and the tab to switch
            setTimeout(() => {
                window.dispatchEvent(new CustomEvent('insert-suggestion', { detail: { text, mode } }));
                toast.success('Sugestia została przesłana do edytora.');
            }, 400);
            return;
        }

        setIsLoading(true);
        try {
            let targetId = null;
            let foundSectionType = null;
            const sections = await getProjectSections(projectId);
            
            const findSection = (query: string) => {
                if (!query) return null;
                const q = query.trim().toLowerCase();
                if (!q) return null;
                
                let bestMatch = null;
                let highestScore = 0;

                sections.forEach((s: any) => {
                    const st = s.section_type?.toLowerCase() || "";
                    const stClean = s.section_type?.replace(/_/g, ' ').toLowerCase() || "";
                    const title = s.title?.trim().toLowerCase() || "";
                    
                    let score = 0;
                    if (s.id === query) {
                        score = 200;
                    } else if (st === q || title === q) {
                        score = 100;
                    } else if (stClean === q) {
                        score = 90;
                    } else if ((st && q.includes(st)) || (stClean && q.includes(stClean))) {
                        score = 80;
                    } else if (title && q && title.includes(q)) {
                        score = 70;
                    } else if (q && title && q.includes(title)) {
                        score = title.length >= 4 ? 60 : 0;
                    } else if (stClean && q && stClean.includes(q)) {
                        score = 50;
                    } else if (q && stClean && q.includes(stClean)) {
                        score = stClean.length >= 4 ? 40 : 0;
                    } else if (q && title) {
                        const targetWords = q.split(/\s+/).filter((w: string) => w.length >= 4);
                        for (const w of targetWords) {
                            if (title.includes(w) || (stClean && stClean.includes(w))) {
                                score = 30;
                                break;
                            }
                        }
                    }

                    if (score > highestScore) {
                        highestScore = score;
                        bestMatch = s;
                    }
                });
                return bestMatch;
            };

            let matchingSection: any = null;
            if (sectionTarget && sectionTarget !== 'Aktywna sekcja' && sectionTarget !== activeSectionTitle) {
                matchingSection = findSection(sectionTarget);
            }
            
            if (!matchingSection && activeSectionId) {
                matchingSection = findSection(activeSectionId);
            }
            
            if (matchingSection) {
                targetId = matchingSection.id;
                foundSectionType = matchingSection.section_type;
            }
            
            if (targetId) {
                await updateProjectSection(projectId, targetId, text);
                window.dispatchEvent(new CustomEvent('external-section-update', { 
                    detail: { sectionType: foundSectionType, content: text } 
                }));
                window.dispatchEvent(new CustomEvent('refresh-sections'));
                toast.success(`Zawartość sekcji została pomyślnie nadpisana w bazie.`);
                
                window.dispatchEvent(new CustomEvent('navigate-to-section', {
                    detail: { sectionType: foundSectionType }
                }));
            } else {
                toast.error("Nie można ustalić sekcji docelowej upewnij się, jaką sekcję edytujesz.");
            }
        } catch (e) {
            console.error(e);
            toast.error("Wystąpił błąd podczas nadpisywania sekcji w bazie.");
        } finally {
            setIsLoading(false);
        }
    };

    const renderMessageContent = (content: string) => {
        const parts = content.split(/(<SUGGESTION[^>]*>[\s\S]*?<\/SUGGESTION>)/);
        
        return (
            <>
                {parts.map((part, i) => {
                    const match = part.match(/<SUGGESTION(?: section="([^"]*)")?>([\s\S]*?)<\/SUGGESTION>/);
                    if (match) {
                        const sectionName = match[1] || activeSectionTitle || "Aktywna sekcja";
                        const suggestionText = match[2].trim();
                        return (
                            <div key={i} style={{ marginTop: '1rem', background: 'rgba(16, 185, 129, 0.05)', border: '1px solid rgba(16, 185, 129, 0.3)', borderRadius: '8px', overflow: 'hidden' }}>
                                <div style={{ padding: '0.6rem 1rem', background: 'rgba(16, 185, 129, 0.15)', borderBottom: '1px solid rgba(16, 185, 129, 0.2)', fontSize: '0.8rem', fontWeight: 600, color: '#34d399', display: 'flex', justifyContent: 'space-between', alignItems: 'center' }}>
                                    <span style={{ display: 'flex', alignItems: 'center', gap: '0.5rem' }}>
                                        <Sparkles size={16} />
                                        <div style={{ padding: '2px 6px', background: 'rgba(16, 185, 129, 0.2)', borderRadius: '4px', fontSize: '0.65rem', textTransform: 'uppercase', letterSpacing: '0.5px' }}>SUGESTIA</div>
                                        Dla sekcji: {sectionName}
                                    </span>
                                </div>
                                <div style={{ padding: '1rem', fontSize: '0.85rem', whiteSpace: 'pre-wrap', color: 'var(--text-secondary)' }}>
                                    {suggestionText}
                                </div>
                                <div style={{ padding: '0.5rem 1rem', borderTop: '1px solid rgba(255,255,255,0.05)', display: 'flex', flexWrap: 'wrap', gap: '0.5rem', background: 'rgba(0,0,0,0.1)' }}>
                                    <button onClick={() => handleApplySuggestion(suggestionText, 'insert')} className="btn hover-lift" style={{ flex: 1, padding: '0.4rem', fontSize: '0.8rem', background: '#34d399', color: '#000', fontWeight: 600, border: 'none', borderRadius: '4px', cursor: 'pointer', minWidth: '140px' }} title="Wkleja tekst w miejscu kursora w aktualnie otwartej sekcji">Wklej w miejscu kursora</button>
                                    <button onClick={() => {
                                        if (window.confirm(`Czy na pewno chcesz nadpisać całą treść sekcji "${sectionName}" w bazie danych? Obecna treść tej sekcji zostanie utracona!`)) {
                                            handleApplySuggestion(suggestionText, 'replace', sectionName);
                                        }
                                    }} className="btn hover-lift" style={{ flex: 1, padding: '0.4rem', fontSize: '0.8rem', background: 'rgba(255,255,255,0.1)', color: '#fff', border: '1px solid rgba(255,255,255,0.1)', borderRadius: '4px', cursor: 'pointer', minWidth: '140px' }} title={`Zastępuje treść sekcji: ${sectionName}`}>Nadpisz sekcję: {sectionName}</button>
                                </div>
                            </div>
                        );
                    }
                    return <span key={i} style={{ whiteSpace: 'pre-wrap' }}>{part}</span>;
                })}
            </>
        );
    };

    const handleSend = async (overrideInput?: string) => {
        const textToUse = typeof overrideInput === 'string' ? overrideInput : input;
        if (!textToUse.trim() || isLoading) return;

        const userMsg: ChatMessage = { id: Date.now().toString(), role: 'user', content: textToUse };
        setMessages(prev => [...prev, userMsg]);
        if (typeof overrideInput !== 'string') {
            setInput('');
        }
        setIsLoading(true);

        try {
            const agentMsg = await sendProjectChatMessage(projectId, userMsg.content, activeSectionId, activeSectionTitle);
            setMessages(prev => [...prev, agentMsg]);
        } catch (error: any) {
            console.error(error);
            toast.error("Nie udało się pobrać odpowiedzi po kilku próbach.");
            const errorMsg: ChatMessage = {
                id: (Date.now() + 1).toString(),
                role: 'assistant',
                content: "Przepraszam, napotkałem problem techniczny (np. przeciążenie serwerów LLM). System podjął próby automatycznej naprawy, ale niestety nie powiodły się one w tej chwili.\n\nProszę, spróbuj ponownie za chwilę.",
                isError: true,
                originalInput: textToUse
            };
            setMessages(prev => [...prev, errorMsg]);
        } finally {
            setIsLoading(false);
        }
    };
    
    useEffect(() => {
        handleSendRef.current = handleSend;
    }, [handleSend]);

    const handleKeyDown = (e: React.KeyboardEvent) => {
        if (e.key === 'Enter' && !e.shiftKey) {
            e.preventDefault();
            handleSend();
        }
    };

    return (
        <div className="chat-panel-container" style={{ position: 'fixed', bottom: '9rem', right: '3rem', zIndex: 1000, display: 'flex', flexDirection: 'column', alignItems: 'flex-end', pointerEvents: 'none' }}>
            
            <AnimatePresence>
                {isOpen && (
                    <motion.div
                        initial={{ opacity: 0, y: 20, scale: 0.95 }}
                        animate={{ opacity: 1, y: 0, scale: 1 }}
                        exit={{ opacity: 0, y: 20, scale: 0.95 }}
                        transition={{ duration: 0.2 }}
                        style={{
                            width: '100%',
                            maxWidth: '430px',
                            height: '600px',
                            maxHeight: isPinned ? '100vh' : '80vh',
                            background: 'var(--bg-elevated)',
                            border: '1px solid rgba(255,255,255,0.1)',
                            borderRadius: isPinned ? '0' : '16px',
                            boxShadow: isPinned ? 'none' : '0 10px 40px rgba(0,0,0,0.5)',
                            display: 'flex',
                            flexDirection: 'column',
                            marginBottom: isPinned ? '0' : '1rem',
                            position: isPinned ? 'fixed' : 'relative',
                            right: isPinned ? 0 : 'auto',
                            top: isPinned ? 0 : 'auto',
                            bottom: isPinned ? 0 : 'auto',
                            pointerEvents: 'auto',
                            overflow: 'hidden',
                            zIndex: 1000
                        }}
                    >
                        {/* HEADER */}
                        <div style={{ padding: '1rem', borderBottom: '1px solid rgba(255,255,255,0.05)', display: 'flex', alignItems: 'flex-start', justifyContent: 'space-between', background: 'rgba(0,0,0,0.2)' }}>
                            <div style={{ display: 'flex', alignItems: 'center', gap: '0.8rem' }}>
                                <div style={{ width: '32px', height: '32px', borderRadius: '8px', background: 'rgba(99, 102, 241, 0.2)', color: '#818cf8', display: 'flex', alignItems: 'center', justifyContent: 'center' }}>
                                    <Bot size={16} />
                                </div>
                                <div>
                                    <h3 style={{ margin: 0, fontSize: '1rem', fontWeight: 600 }}>Asystent Projektu (Ctrl+J)</h3>
                                    {projectName && (
                                        <div style={{ fontSize: '0.65rem', background: 'rgba(255,255,255,0.1)', padding: '2px 6px', borderRadius: '10px', marginTop: '4px', display: 'inline-block', maxWidth: '180px', whiteSpace: 'nowrap', overflow: 'hidden', textOverflow: 'ellipsis' }}>
                                            {projectName}
                                        </div>
                                    )}
                                </div>
                            </div>
                            <div style={{ display: 'flex', gap: '0.3rem' }}>
                                <button onClick={handleClearHistory} style={{ background: 'transparent', border: 'none', color: 'var(--text-muted)', cursor: 'pointer', padding: '0.5rem' }} className="hover-bg rounded" title="Wyczyść historię">
                                    <Trash2 size={16} />
                                </button>
                                <button onClick={() => setIsPinned(!isPinned)} style={{ background: 'transparent', border: 'none', color: isPinned ? '#818cf8' : 'var(--text-muted)', cursor: 'pointer', padding: '0.5rem' }} className="hover-bg rounded" title={isPinned ? "Odepnij panel" : "Przypnij jako sidebar"}>
                                    {isPinned ? <Pin size={16} fill="currentColor" /> : <Pin size={16} />}
                                </button>
                                {!isPinned && (
                                    <button onClick={() => setIsOpen(false)} style={{ background: 'transparent', border: 'none', color: 'var(--text-muted)', cursor: 'pointer', padding: '0.5rem' }} className="hover-bg rounded" title="Zamknij (Ctrl+J)">
                                        <X size={18} />
                                    </button>
                                )}
                            </div>
                        </div>

                        {/* MESSAGES */}
                        <div style={{ flex: 1, overflowY: 'auto', padding: '1.5rem', display: 'flex', flexDirection: 'column', gap: '1.5rem' }}>
                            {messages.length === 0 ? (
                                <div style={{ display: 'flex', flexDirection: 'column', alignItems: 'flex-start' }}>
                                    <div style={{
                                        maxWidth: '85%',
                                        padding: '1rem',
                                        borderRadius: '12px',
                                        background: 'rgba(255,255,255,0.03)',
                                        border: '1px solid rgba(255,255,255,0.05)',
                                        color: 'var(--text-primary)',
                                        fontSize: '0.9rem',
                                        lineHeight: '1.5'
                                    }}>
                                        Cześć! Jestem Twoim Asystentem Projektu.<br/><br/>
                                        Mogę pomóc w pisaniu sekcji, wyjaśnianiu regulaminów lub sugerowaniu poprawek.<br/><br/>
                                        W czym mogę Ci pomóc?
                                    </div>
                                </div>
                            ) : (
                                messages.map((msg) => (
                                    <div key={msg.id} style={{ display: 'flex', flexDirection: 'column', alignItems: msg.role === 'user' ? 'flex-end' : 'flex-start' }}>
                                        <div style={{
                                            maxWidth: '85%',
                                            padding: '1rem',
                                            borderRadius: '12px',
                                            background: msg.role === 'user' ? 'rgba(99, 102, 241, 0.2)' : 'rgba(255,255,255,0.03)',
                                            border: `1px solid ${msg.role === 'user' ? 'rgba(99, 102, 241, 0.3)' : 'rgba(255,255,255,0.05)'}`,
                                            color: 'var(--text-primary)',
                                            fontSize: '0.9rem',
                                            lineHeight: '1.5'
                                        }}>
                                            {msg.role === 'assistant' ? renderMessageContent(msg.content) : msg.content}
                                            
                                            {msg.role === 'assistant' && !msg.isError && (
                                                <div style={{ marginTop: '0.5rem', display: 'flex', justifyContent: 'flex-end' }}>
                                                    <button 
                                                        onClick={() => {
                                                            navigator.clipboard.writeText(msg.content);
                                                            toast.success('Skopiowano odpowiedź do schowka.');
                                                        }}
                                                        style={{ fontSize: '0.75rem', padding: '0.3rem 0.6rem', border: '1px solid rgba(255,255,255,0.1)', background: 'rgba(255,255,255,0.05)', color: '#fff', borderRadius: '4px', cursor: 'pointer', marginTop: '0.5rem' }}
                                                        className="hover-bg"
                                                    >
                                                        Kopiuj Odpowiedź
                                                    </button>
                                                </div>
                                            )}
                                            {msg.isError && msg.originalInput && (
                                                <div style={{ marginTop: '1rem', display: 'flex', justifyContent: 'flex-end' }}>
                                                    <button 
                                                        onClick={() => {
                                                            // Remove the error message from the UI and retry sending the prompt
                                                            setMessages(prev => prev.filter(m => m.id !== msg.id));
                                                            handleSend(msg.originalInput);
                                                        }}
                                                        style={{ fontSize: '0.8rem', padding: '0.4rem 0.8rem', background: '#ef4444', color: '#fff', border: 'none', borderRadius: '4px', cursor: 'pointer', display: 'flex', alignItems: 'center', gap: '0.4rem' }}
                                                        className="hover-lift"
                                                    >
                                                        Ponów zapytanie
                                                    </button>
                                                </div>
                                            )}
                                        </div>
                                    </div>
                                ))
                            )}
                            
                            {isLoading && (
                                <div style={{ alignSelf: 'flex-start', maxWidth: '85%', padding: '1rem', borderRadius: '12px', background: 'rgba(255,255,255,0.03)', border: '1px solid rgba(255,255,255,0.05)', display: 'flex', alignItems: 'center', gap: '0.8rem' }}>
                                    <div style={{ display: 'flex', gap: '0.3rem' }}>
                                        <div style={{ width: '8px', height: '8px', borderRadius: '50%', background: '#818cf8', animation: 'pulse 1.5s infinite' }} />
                                        <div style={{ width: '8px', height: '8px', borderRadius: '50%', background: '#818cf8', animation: 'pulse 1.5s infinite 0.2s' }} />
                                        <div style={{ width: '8px', height: '8px', borderRadius: '50%', background: '#818cf8', animation: 'pulse 1.5s infinite 0.4s' }} />
                                    </div>
                                    <span style={{ fontSize: '0.85rem', color: 'var(--text-secondary)' }}>Przetwarzanie zapytania... Prosimy o chwilę cierpliwości.</span>
                                </div>
                            )}
                            <div ref={messagesEndRef} />
                        </div>

                        {/* INPUT */}
                        <div style={{ padding: '1.2rem', borderTop: '1px solid rgba(255,255,255,0.05)', background: 'rgba(0,0,0,0.1)' }}>
                            <div style={{ position: 'relative' }}>
                                <textarea
                                    value={input}
                                    onChange={(e) => setInput(e.target.value)}
                                    onKeyDown={handleKeyDown}
                                    placeholder="Napisz wiadomość do Asystenta..."
                                    style={{
                                        width: '100%',
                                        background: 'rgba(255,255,255,0.03)',
                                        border: '1px solid rgba(255,255,255,0.1)',
                                        borderRadius: '8px',
                                        padding: '0.8rem 3rem 0.8rem 1rem',
                                        color: '#fff',
                                        resize: 'none',
                                        height: '60px',
                                        fontSize: '0.9rem',
                                        outline: 'none',
                                        transition: 'all 0.2s'
                                    }}
                                    className="focus-ring"
                                />
                                <button 
                                    onClick={() => handleSend()}
                                    disabled={!input.trim() || isLoading}
                                    style={{ 
                                        position: 'absolute', 
                                        right: '0.5rem', 
                                        bottom: '0.5rem', 
                                        height: '42px', 
                                        width: '42px', 
                                        borderRadius: '6px', 
                                        background: input.trim() && !isLoading ? '#6366f1' : 'rgba(255,255,255,0.05)', 
                                        color: input.trim() && !isLoading ? '#fff' : 'var(--text-muted)', 
                                        border: 'none', 
                                        display: 'flex', 
                                        alignItems: 'center', 
                                        justifyContent: 'center', 
                                        cursor: input.trim() && !isLoading ? 'pointer' : 'default',
                                        transition: 'all 0.2s'
                                    }}
                                >
                                    <Send size={16} />
                                </button>
                            </div>
                        </div>

                    </motion.div>
                )}
            </AnimatePresence>

            {/* TOGGLE BUTTON - Hidden if pinned */}
            {!isPinned && (
                <motion.button
                    className="tour-step-chat"
                    whileHover={{ scale: 1.05 }}
                    whileTap={{ scale: 0.95 }}
                    onClick={() => setIsOpen(!isOpen)}
                    style={{
                        width: '60px',
                        height: '60px',
                        borderRadius: '30px',
                        background: '#6366f1',
                        color: '#fff',
                        border: 'none',
                        boxShadow: '0 4px 20px rgba(99, 102, 241, 0.4)',
                        display: 'flex',
                        alignItems: 'center',
                        justifyContent: 'center',
                        cursor: 'pointer',
                        pointerEvents: 'auto',
                        zIndex: 1001,
                        marginTop: '1rem' 
                    }}
                >
                    {isOpen ? <ChevronDown size={28} /> : <Bot size={28} />}
                </motion.button>
            )}
            <style>{`
                @keyframes pulse { 0%, 100% { opacity: 0.4; } 50% { opacity: 1; } }
            `}</style>
        </div>
    );
};

export default ProjectChatPanel;