import React, { useState, useEffect, useRef } from 'react';
import { Head, Link, router } from '@inertiajs/react';
import EmployerLayout from '../../../Layouts/EmployerLayout';
import { 
    Send, 
    ArrowLeft, 
    CheckCircle2, 
    Globe2, 
    DollarSign, 
    Sparkles,
    MoreVertical,
    Phone,
    Video,
    Paperclip,
    Search,
    Info,
    Calendar,
    Briefcase,
    ShieldCheck,
    ChevronRight,
    MapPin,
    Smile,
    X,
    MessageSquare,
    Eye,
    UploadCloud,
    FileText
} from 'lucide-react';
import { toast } from 'sonner';

export default function Show({ conversation, initialMessages, conversations = [] }) {
    const [messages, setMessages] = useState(initialMessages || []);
    const [input, setInput] = useState('');
    const [isTyping, setIsTyping] = useState(false);
    const [searchTerm, setSearchTerm] = useState('');
    const [showProfile, setShowProfile] = useState(true);
    const [showAttachmentModal, setShowAttachmentModal] = useState(false);
    const [uploadedFiles, setUploadedFiles] = useState([]);
    const messagesEndRef = useRef(null);

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

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

    useEffect(() => {
        setMessages(initialMessages || []);
    }, [initialMessages]);

    // Simulate typing indicator when conversation opens
    useEffect(() => {
        setIsTyping(true);
        const timer = setTimeout(() => setIsTyping(false), 2500);
        return () => clearTimeout(timer);
    }, [conversation.id]);

    const filteredConversations = (conversations || []).filter(c => 
        c.worker_name.toLowerCase().includes(searchTerm.toLowerCase())
    );

    const sendMsg = (text) => {
        if (!text.trim()) return;

        // Optimistically update message feed
        const newMsg = {
            id: Date.now(),
            sender: 'employer',
            text: text,
            time: 'Just Now',
            read: false
        };
        setMessages(prev => [...prev, newMsg]);
        setInput('');

        router.post(`/employer/messages/${conversation.id}/send`, {
            text: text
        }, {
            preserveScroll: true,
            onSuccess: () => {
                // Show immediate confirmation of the push alert popping up on worker mobile app
                toast.success(`🔔 Direct Mobile Push Notification sent!`, {
                    description: `Popped up instantly on ${conversation.worker_name}'s mobile device.`,
                    duration: 4500,
                });

                // Simulate worker typing response shortly after
                setTimeout(() => {
                    setIsTyping(true);
                    setTimeout(() => {
                        setIsTyping(false);
                        const autoReply = {
                            id: Date.now() + 1,
                            sender: 'worker',
                            text: "Thank you for your response! I have reviewed your offer proposal and am looking forward to our video interview.",
                            time: 'Just Now'
                        };
                        setMessages(prev => [...prev, autoReply]);
                        
                        // Pop up a clear message received notification for the sponsor
                        toast.info(`✉️ New message from ${conversation.worker_name}!`, {
                            description: autoReply.text,
                            duration: 5000
                        });
                    }, 2000);
                }, 1500);
            }
        });
    };

    const handleFormSubmit = (e) => {
        e.preventDefault();
        sendMsg(input);
    };

    const handleFileUpload = (e) => {
        const file = e.target.files[0];
        if (!file) return;

        const newFile = {
            name: file.name,
            size: (file.size / 1024).toFixed(1) + ' KB',
            date: 'Today'
        };

        setUploadedFiles([...uploadedFiles, newFile]);
        toast.success("📎 Document attached successfully!");
        setShowAttachmentModal(false);
        
        // Optimistically insert attachment message
        sendMsg(`[Document Attached: ${file.name}]`);
    };

    const chips = [
        "Are you available for a video interview today?",
        "What is your final expected salary?",
        "Can you transfer your visa immediately?"
    ];

    return (
        <EmployerLayout title={null} fullPage={true}>
            <Head title={`Chat with ${conversation.worker_name} - Messages`} />

            <div className="flex h-full bg-[#FAFBFF] overflow-hidden select-none w-full">
                {/* Conversation List Sidebar (Desktop) */}
                <aside className="hidden xl:flex w-90 border-r border-slate-200 flex-col flex-shrink-0 bg-white shadow-sm z-30">
                    <div className="p-6 border-b border-slate-100">
                        <div className="flex items-center justify-between mb-6">
                            <h2 className="font-black text-2xl text-slate-900 tracking-tight">Messages Hub</h2>
                            <span className="text-[9px] font-black bg-emerald-50 text-emerald-700 px-2 py-0.5 rounded uppercase tracking-wider">
                                SSL SECURE
                            </span>
                        </div>
                        <div className="relative">
                            <input
                                type="text"
                                placeholder="Search conversations..."
                                value={searchTerm}
                                onChange={(e) => setSearchTerm(e.target.value)}
                                className="w-full pl-5 pr-4 py-3 bg-slate-50 border-none rounded-2xl text-sm font-bold focus:ring-2 focus:ring-blue-100 transition-all placeholder:text-slate-400 outline-none"
                            />
                        </div>
                    </div>

                    <div className="flex-1 overflow-y-auto divide-y divide-slate-50">
                        {filteredConversations.map((c) => (
                            <Link
                                key={c.id}
                                href={`/employer/messages/${c.id}`}
                                className={`flex items-center space-x-4 p-5 transition-all relative group ${
                                    c.id === conversation.id ? 'bg-blue-50/50' : 'hover:bg-slate-50'
                                }`}
                            >
                                {c.id === conversation.id && (
                                    <div className="absolute left-0 top-0 bottom-0 w-1 bg-[#185FA5] rounded-r-full shadow-[0_0_15px_rgba(24,95,165,0.4)]" />
                                )}
                                
                                <div className="relative flex-shrink-0">
                                    <div className={`w-12 h-12 rounded-[20px] text-white flex items-center justify-center font-black text-lg shadow-sm ${
                                        c.id === conversation.id ? 'bg-gradient-to-br from-[#185FA5] to-blue-600' : 'bg-slate-200 text-slate-400'
                                    }`}>
                                        {c.worker_name.charAt(0)}
                                    </div>
                                    <span className="absolute -bottom-1 -right-1 w-3.5 h-3.5 bg-emerald-500 border-4 border-white rounded-full shadow-sm" />
                                </div>

                                <div className="flex-1 min-w-0">
                                    <div className="flex items-center justify-between mb-1">
                                        <span className={`text-xs font-black truncate ${c.id === conversation.id ? 'text-[#185FA5]' : 'text-slate-900'}`}>
                                            {c.worker_name}
                                        </span>
                                        <span className="text-[9px] text-slate-400 font-bold uppercase tracking-tighter">{c.sent_at}</span>
                                    </div>
                                    <p className={`text-[11px] font-bold truncate leading-tight ${c.unread ? 'text-slate-900' : 'text-slate-400'}`}>
                                        {c.last_message}
                                    </p>
                                </div>
                                
                                {c.unread && (
                                    <div className="w-2.5 h-2.5 bg-red-500 rounded-full flex-shrink-0 shadow-[0_0_8px_rgba(239,68,68,0.4)]" />
                                )}
                            </Link>
                        ))}
                    </div>
                </aside>

                {/* Main Chat Interface */}
                <div className="flex-1 flex flex-col h-full bg-white relative z-10 shadow-2xl overflow-hidden">
                    {/* Header */}
                    <div className="bg-white p-4 sm:p-5 border-b border-slate-100 flex items-center justify-between z-45 sticky top-0 shadow-xs">
                        <div className="flex items-center space-x-3">
                            <Link
                                href="/employer/messages"
                                className="xl:hidden p-2 text-slate-400 hover:text-[#185FA5] hover:bg-blue-50 rounded-2xl transition-all"
                            >
                                <ArrowLeft className="w-5 h-5" />
                            </Link>
                            
                            <div className="relative group cursor-pointer" onClick={() => setShowProfile(!showProfile)}>
                                <div className="w-11 h-11 rounded-2xl bg-gradient-to-br from-[#185FA5] to-blue-600 text-white flex items-center justify-center font-black text-base shadow-md">
                                    {conversation.worker_name.charAt(0)}
                                </div>
                                <span className="absolute -bottom-1 -right-1 w-3.5 h-3.5 bg-emerald-500 border-4 border-white rounded-full shadow-lg" />
                            </div>

                            <div>
                                <div className="flex items-center gap-2">
                                    <h3 className="font-extrabold text-slate-900 text-sm tracking-tight">{conversation.worker_name}</h3>
                                    <span className="bg-emerald-50 text-emerald-600 p-0.5 rounded-full shadow-sm" title="OCR Verified Passport">
                                        <ShieldCheck className="w-3.5 h-3.5" />
                                    </span>
                                </div>
                                <div className="flex items-center space-x-1.5 mt-0.5">
                                    <span className="text-[9px] font-black text-slate-400 uppercase tracking-widest">
                                        Active Now
                                    </span>
                                </div>
                            </div>
                        </div>

                        {/* WhatsApp Bridge Widget & Dossier Button */}
                        <div className="flex items-center space-x-2">
                            <a 
                                href={`https://wa.me/971501112222?text=Hi, I am reviewing candidate ${conversation.worker_name} (${conversation.nationality}) on the platform. Please assist with hiring workflow details.`}
                                target="_blank"
                                rel="noreferrer"
                                className="px-3.5 py-2 bg-emerald-50 text-emerald-800 border border-emerald-200 hover:bg-emerald-100 rounded-xl transition-all shadow-xs flex items-center space-x-1.5 text-xs font-bold"
                            >
                                <MessageSquare className="w-4 h-4 text-emerald-600 fill-emerald-600" />
                                <span className="hidden sm:inline">WhatsApp Bridge</span>
                            </a>

                            <button 
                                onClick={() => setShowProfile(!showProfile)}
                                className={`p-2.5 rounded-xl transition-all shadow-xs border ${
                                    showProfile 
                                        ? 'bg-blue-50 border-blue-100 text-[#185FA5]' 
                                        : 'bg-slate-50 border-slate-200 text-slate-400 hover:text-[#185FA5]'
                                }`}
                                title="Toggle Context Sidebar"
                            >
                                <Info className="w-4.5 h-4.5" />
                            </button>
                        </div>
                    </div>

                    {/* Chat Messages Log */}
                    <div className="flex-1 px-6 py-6 overflow-y-auto bg-[#F8FAFC]/60 space-y-6 scroll-smooth">
                        <div className="flex flex-col items-center mb-6">
                            <div className="bg-white border border-slate-200 px-4 py-1.5 rounded-full shadow-xs">
                                <span className="text-[9px] font-black text-slate-400 uppercase tracking-widest">Today • Realtime Chat Logs</span>
                            </div>
                        </div>

                        {messages.map((msg, idx) => {
                            const isEmp = msg.sender === 'employer';
                            return (
                                <div
                                    key={msg.id}
                                    className={`flex w-full ${isEmp ? 'justify-end' : 'justify-start'} animate-in fade-in slide-in-from-bottom-4 duration-300`}
                                >
                                    <div className={`flex flex-col ${isEmp ? 'items-end' : 'items-start'} max-w-[80%] sm:max-w-[65%]`}>
                                        <div className={`px-5 py-3 rounded-2xl text-xs font-semibold leading-relaxed shadow-xs relative ${
                                            isEmp 
                                                ? 'bg-[#185FA5] text-white rounded-tr-none' 
                                                : 'bg-white border border-slate-100 text-slate-800 rounded-tl-none'
                                        }`}>
                                            {msg.text}
                                        </div>
                                        <div className="flex items-center space-x-1 mt-1 px-1 text-[9px] font-bold text-slate-400 uppercase">
                                            <span>{msg.time}</span>
                                            {isEmp && (
                                                <span className="flex items-center space-x-0.5 text-emerald-600">
                                                    <span>•</span>
                                                    <span>Read</span>
                                                    <CheckCircle2 className="w-2.5 h-2.5" />
                                                </span>
                                            )}
                                        </div>
                                    </div>
                                </div>
                            );
                        })}

                        {isTyping && (
                            <div className="flex w-full justify-start animate-in fade-in slide-in-from-bottom-2">
                                <div className="bg-white border border-slate-100 px-4 py-3 rounded-2xl rounded-tl-none shadow-xs flex items-center space-x-1.5">
                                    <div className="w-1.5 h-1.5 bg-[#185FA5] rounded-full animate-bounce [animation-delay:-0.3s]"></div>
                                    <div className="w-1.5 h-1.5 bg-[#185FA5] rounded-full animate-bounce [animation-delay:-0.15s]"></div>
                                    <div className="w-1.5 h-1.5 bg-[#185FA5] rounded-full animate-bounce"></div>
                                </div>
                            </div>
                        )}
                        <div ref={messagesEndRef} />
                    </div>

                    {/* Quick replies & typing input */}
                    <div className="bg-white border-t border-slate-100 p-5 space-y-4 shadow-sm shrink-0">
                        <div className="flex items-center space-x-2.5 overflow-x-auto scrollbar-none pb-1.5">
                            <div className="flex-shrink-0 p-1.5 bg-blue-50 text-[#185FA5] rounded-lg">
                                <Sparkles className="w-3.5 h-3.5" />
                            </div>
                            {chips.map((chip, idx) => (
                                <button
                                    key={idx}
                                    onClick={() => sendMsg(chip)}
                                    className="bg-slate-50 hover:bg-[#185FA5] text-slate-600 hover:text-white px-4 py-2 rounded-xl text-[10px] font-black uppercase tracking-wider flex-shrink-0 transition-all border border-slate-100"
                                >
                                    {chip}
                                </button>
                            ))}
                        </div>

                        <form onSubmit={handleFormSubmit} className="flex items-center gap-3">
                            <button 
                                type="button" 
                                onClick={() => setShowAttachmentModal(true)}
                                className="p-3 bg-slate-50 text-slate-400 hover:text-slate-600 rounded-xl transition-all border border-slate-100"
                                title="Attach Document Details"
                            >
                                <Paperclip className="w-5 h-5" />
                            </button>
                            <input
                                value={input}
                                onChange={(e) => setInput(e.target.value)}
                                placeholder="Type a compliant secure message..."
                                className="flex-1 px-5 py-3.5 bg-slate-50 rounded-xl text-xs font-semibold outline-none border border-transparent focus:border-slate-200 transition-all"
                            />
                            <button
                                type="submit"
                                disabled={!input.trim()}
                                className="bg-[#185FA5] hover:bg-[#144f8a] disabled:bg-slate-200 text-white p-3.5 rounded-xl transition-all shadow-xs flex items-center justify-center flex-shrink-0"
                            >
                                <Send className="w-5 h-5" />
                            </button>
                        </form>
                    </div>
                </div>

                {/* Candidate Context Sidebar (Right) */}
                {showProfile && (
                    <aside className="hidden lg:flex w-72 2xl:w-80 border-l border-slate-200 flex-col flex-shrink-0 bg-white z-20 animate-in slide-in-from-right-10 duration-350 overflow-y-auto">
                        <div className="p-6 space-y-6">
                            <div className="text-center space-y-3 pb-4 border-b border-slate-100">
                                <div className="w-20 h-20 rounded-[30px] bg-gradient-to-br from-[#185FA5] to-blue-600 text-white flex items-center justify-center font-black text-2xl mx-auto shadow-md relative">
                                    {conversation.worker_name.charAt(0)}
                                    <span className="absolute -bottom-1 -right-1 bg-emerald-500 p-1 rounded-lg border-2 border-white shadow">
                                        <ShieldCheck className="w-4 h-4 text-white" />
                                    </span>
                                </div>
                                <div>
                                    <h4 className="font-extrabold text-base text-slate-900 tracking-tight">{conversation.worker_name}</h4>
                                    <span className="inline-block bg-slate-50 px-2 py-0.5 border border-slate-200 rounded text-[9px] uppercase font-black tracking-widest mt-1">
                                        {conversation.category}
                                    </span>
                                </div>
                            </div>

                            <div className="grid grid-cols-2 gap-2 text-center text-xs font-bold">
                                <div className="bg-slate-50/70 p-3 rounded-xl border border-slate-100">
                                    <DollarSign className="w-3.5 h-3.5 text-emerald-600 mx-auto mb-1" />
                                    <div className="text-[8px] font-black text-slate-400 uppercase tracking-widest">Expected</div>
                                    <div className="text-slate-800 mt-0.5 truncate">{conversation.salary}</div>
                                </div>
                                <div className="bg-slate-50/70 p-3 rounded-xl border border-slate-100">
                                    <MapPin className="w-3.5 h-3.5 text-blue-600 mx-auto mb-1" />
                                    <div className="text-[8px] font-black text-slate-400 uppercase tracking-widest">Region</div>
                                    <div className="text-slate-800 mt-0.5 truncate">{conversation.nationality}</div>
                                </div>
                            </div>

                            <div className="space-y-3">
                                <h5 className="text-[9px] font-black text-slate-400 uppercase tracking-widest pl-1">Compliance Profile</h5>
                                <div className="space-y-2">
                                    {[
                                        { label: 'Visa Transfer', value: 'Transferable', icon: Briefcase, color: 'text-blue-500' },
                                        { label: 'Medical Status', value: 'Cleared', icon: ShieldCheck, color: 'text-emerald-500' },
                                        { label: 'Passport OCR', value: 'Verified', icon: FileText, color: 'text-slate-500' }
                                    ].map((item, i) => (
                                        <div key={i} className="flex items-center justify-between p-3 bg-slate-50/40 border border-slate-100 rounded-xl text-[10px] font-bold text-slate-600">
                                            <div className="flex items-center space-x-2">
                                                <item.icon className={`w-3.5 h-3.5 ${item.color}`} />
                                                <span className="text-slate-500">{item.label}</span>
                                            </div>
                                            <span className="text-slate-900 font-extrabold">{item.value}</span>
                                        </div>
                                    ))}
                                </div>
                            </div>

                            <div className="pt-2">
                                <Link
                                    href={`/employer/workers/${conversation.id}`}
                                    className="w-full bg-[#185FA5] hover:bg-[#144f8a] text-white py-3 rounded-xl text-xs font-black uppercase tracking-widest flex items-center justify-center space-x-1.5 shadow-xs"
                                >
                                    <Eye className="w-4 h-4" />
                                    <span>Open Worker Profile</span>
                                </Link>
                            </div>
                        </div>
                    </aside>
                )}
            </div>

            {/* Interactive File Attachment Modal Placeholder */}
            {showAttachmentModal && (
                <div className="fixed inset-0 bg-slate-900/60 backdrop-blur-xs flex items-center justify-center p-4 z-50 animate-fade-in">
                    <div className="bg-white rounded-3xl w-full max-w-sm border border-slate-200 shadow-2xl p-6 relative animate-zoom-in space-y-4">
                        <button
                            onClick={() => setShowAttachmentModal(false)}
                            className="absolute top-4 right-4 p-2 bg-slate-50 hover:bg-slate-100 rounded-full text-slate-400 hover:text-slate-600 transition-colors"
                        >
                            <X className="w-5 h-5" />
                        </button>

                        <h4 className="font-extrabold text-sm text-slate-900">Attach Verified Sponsor Documents</h4>
                        <p className="text-xs text-slate-500 font-medium leading-relaxed">
                            Upload sponsor papers, employment agreements, or work descriptions to review securely.
                        </p>

                        <div className="border-2 border-dashed border-slate-200 rounded-2xl p-6 text-center space-y-2 relative hover:border-[#185FA5] transition-all bg-slate-50/50">
                            <UploadCloud className="w-10 h-10 text-slate-350 mx-auto" />
                            <div className="text-xs font-bold text-slate-600">Select files or drag here</div>
                            <div className="text-[9px] text-slate-400">PDF, JPG, PNG (Max 5MB)</div>
                            <input 
                                type="file" 
                                onChange={handleFileUpload}
                                className="absolute inset-0 w-full h-full opacity-0 cursor-pointer" 
                            />
                        </div>

                        <div className="flex justify-end pt-2 text-xs font-bold">
                            <button 
                                type="button" 
                                onClick={() => setShowAttachmentModal(false)}
                                className="px-4 py-2 border border-slate-200 hover:bg-slate-50 rounded-xl"
                            >
                                Close
                            </button>
                        </div>
                    </div>
                </div>
            )}

        </EmployerLayout>
    );
}