import React, { useState, useEffect } from 'react';
import { motion, AnimatePresence } from 'framer-motion';
import { BrainCircuit, Loader2, Play, PenTool, BookOpen, Upload, X, FileText, Image, ScanText, Sparkles, Settings } from 'lucide-react';
import { useAuth } from 'react-oidc-context';
import { AuthButton } from './AuthButton';
import { QuizLibrary } from './QuizLibrary';
import { DefaultConfigModal } from './DefaultConfigModal';
import { useQuizLibrary } from '../hooks/useQuizLibrary';
import { useUserConfig } from '../hooks/useUserConfig';
import type { Quiz, GameConfig } from '../types';

type GenerateMode = 'topic' | 'document';

interface LandingProps {
  onGenerate: (options: { topic?: string; questionCount?: number; files?: File[]; useOcr?: boolean }) => void;
  onCreateManual: () => void;
  onLoadQuiz: (quiz: Quiz, quizId?: string) => void;
  onJoin: (pin: string, name: string) => void;
  isLoading: boolean;
  error: string | null;
}

export const Landing: React.FC<LandingProps> = ({ onGenerate, onCreateManual, onLoadQuiz, onJoin, isLoading, error }) => {
  const auth = useAuth();
  const [mode, setMode] = useState<'HOST' | 'JOIN'>('HOST');
  const [generateMode, setGenerateMode] = useState<GenerateMode>('topic');
  const [topic, setTopic] = useState('');
  const [pin, setPin] = useState('');
  const [name, setName] = useState('');
  const [libraryOpen, setLibraryOpen] = useState(false);
  
  const [selectedFiles, setSelectedFiles] = useState<File[]>([]);
  const [questionCount, setQuestionCount] = useState(10);
  const [isDragging, setIsDragging] = useState(false);
  const [useOcr, setUseOcr] = useState(false);
  const [defaultConfigOpen, setDefaultConfigOpen] = useState(false);
  const [editingDefaultConfig, setEditingDefaultConfig] = useState<GameConfig | null>(null);
  
  const hasImageFile = selectedFiles.some(f => f.type.startsWith('image/'));
  const hasDocumentFile = selectedFiles.some(f => !f.type.startsWith('image/') && !['application/pdf', 'text/plain', 'text/markdown', 'text/csv', 'text/html'].includes(f.type));
  const showOcrOption = hasImageFile || hasDocumentFile;

  const { defaultConfig, saving: savingConfig, saveDefaultConfig } = useUserConfig();
  
  const { 
    quizzes, 
    loading: libraryLoading, 
    loadingQuizId,
    deletingQuizId,
    error: libraryError, 
    fetchQuizzes, 
    loadQuiz, 
    deleteQuiz,
    retry: retryLibrary 
  } = useQuizLibrary();

  useEffect(() => {
    if (libraryOpen && auth.isAuthenticated) {
      fetchQuizzes();
    }
  }, [libraryOpen, auth.isAuthenticated, fetchQuizzes]);

  const handleFileSelect = (e: React.ChangeEvent<HTMLInputElement>) => {
    if (e.target.files && e.target.files.length > 0) {
      const newFiles = Array.from(e.target.files);
      setSelectedFiles(prev => [...prev, ...newFiles]);
    }
  };

  const handleDrop = (e: React.DragEvent) => {
    e.preventDefault();
    setIsDragging(false);
    if (e.dataTransfer.files && e.dataTransfer.files.length > 0) {
      const acceptedTypes = ['.pdf', '.txt', '.md', '.docx', '.pptx', '.xlsx', '.odt', '.odp', '.ods', '.rtf', '.jpg', '.jpeg', '.png', '.gif', '.webp'];
      const newFiles = Array.from(e.dataTransfer.files).filter((file: File) => {
        const fileExtension = '.' + file.name.split('.').pop()?.toLowerCase();
        return acceptedTypes.includes(fileExtension) || file.type.startsWith('image/');
      });
      if (newFiles.length > 0) {
        setSelectedFiles(prev => [...prev, ...newFiles]);
      }
    }
  };

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

  const handleDragLeave = (e: React.DragEvent) => {
    e.preventDefault();
    setIsDragging(false);
  };

  const removeFile = (index: number) => {
    setSelectedFiles(prev => prev.filter((_, i) => i !== index));
    if (selectedFiles.length <= 1) {
      setUseOcr(false);
    }
  };
  
  const clearAllFiles = () => {
    setSelectedFiles([]);
    setUseOcr(false);
  };

  const canGenerate = generateMode === 'topic' ? topic.trim() : selectedFiles.length > 0;

  const handleHostSubmit = (e: React.FormEvent) => {
    e.preventDefault();
    if (canGenerate && !isLoading) {
      onGenerate({ 
        topic: generateMode === 'topic' ? topic.trim() : undefined, 
        questionCount, 
        files: generateMode === 'document' ? selectedFiles : undefined,
        useOcr: generateMode === 'document' && showOcrOption ? useOcr : undefined
      });
    }
  };

  const handleJoinSubmit = (e: React.FormEvent) => {
    e.preventDefault();
    if (pin.trim() && name.trim()) onJoin(pin, name);
  };

  const handleLoadQuiz = async (id: string) => {
    try {
      const quiz = await loadQuiz(id);
      setLibraryOpen(false);
      onLoadQuiz(quiz, id);
    } catch (err) {
      if (err instanceof Error && err.message.includes('redirecting')) {
        return;
      }
      console.error('Failed to load quiz:', err);
    }
  };

  return (
    <div className="flex flex-col items-center justify-center min-h-screen p-4 text-center relative">
      <div className="absolute top-4 right-4 flex items-center gap-2">
        {auth.isAuthenticated && (
          <button
            onClick={() => {
              setEditingDefaultConfig(defaultConfig);
              setDefaultConfigOpen(true);
            }}
            className="p-2.5 bg-white/90 hover:bg-white rounded-xl shadow-md hover:shadow-lg transition-all text-gray-600 hover:text-theme-primary"
            title="Default Game Settings"
          >
            <Settings size={20} />
          </button>
        )}
        <AuthButton />
      </div>
      <motion.div 
        initial={{ scale: 0.8, opacity: 0, rotate: -2 }}
        animate={{ scale: 1, opacity: 1, rotate: 0 }}
        transition={{ type: "spring", bounce: 0.5 }}
        className="bg-white text-gray-900 p-8 rounded-[2rem] shadow-[0_10px_0_rgba(0,0,0,0.1)] max-w-md w-full border-4 border-white/50"
      >
        <div className="flex justify-center mb-6">
          <div className="bg-theme-primary p-4 rounded-3xl rotate-3 shadow-lg">
            <BrainCircuit size={48} className="text-white" />
          </div>
        </div>
        <h1 className="text-5xl font-black mb-2 text-theme-primary tracking-tight">Kaboot</h1>
        <p className="text-gray-500 font-bold mb-6">The AI Quiz Party</p>
        
        <div className="flex bg-gray-100 p-2 rounded-2xl mb-8">
            <button 
                onClick={() => setMode('HOST')}
                className={`flex-1 py-3 rounded-xl font-black text-lg transition-all duration-200 ${mode === 'HOST' ? 'bg-white shadow-md text-theme-primary scale-105' : 'text-gray-400 hover:text-gray-600'}`}
            >
                Host
            </button>
            <button 
                onClick={() => setMode('JOIN')}
                className={`flex-1 py-3 rounded-xl font-black text-lg transition-all duration-200 ${mode === 'JOIN' ? 'bg-white shadow-md text-theme-primary scale-105' : 'text-gray-400 hover:text-gray-600'}`}
            >
                Join
            </button>
        </div>

        {mode === 'HOST' ? (
          <div className="space-y-4">
            <form onSubmit={handleHostSubmit} className="space-y-4">
              <div className="flex bg-gray-100 p-1.5 rounded-xl mb-2">
                <button 
                  type="button"
                  onClick={() => setGenerateMode('topic')}
                  className={`flex-1 py-2 px-3 rounded-lg font-bold text-sm transition-all duration-200 flex items-center justify-center gap-1.5 ${
                    generateMode === 'topic' 
                      ? 'bg-white shadow-sm text-theme-primary' 
                      : 'text-gray-400 hover:text-gray-600'
                  }`}
                >
                  <Sparkles size={16} /> Topic
                </button>
                <button 
                  type="button"
                  onClick={() => setGenerateMode('document')}
                  className={`flex-1 py-2 px-3 rounded-lg font-bold text-sm transition-all duration-200 flex items-center justify-center gap-1.5 ${
                    generateMode === 'document' 
                      ? 'bg-white shadow-sm text-theme-primary' 
                      : 'text-gray-400 hover:text-gray-600'
                  }`}
                >
                  <FileText size={16} /> Document
                </button>
              </div>

              <AnimatePresence mode="wait">
                {generateMode === 'topic' ? (
                  <motion.div
                    key="topic"
                    initial={{ opacity: 0, y: 10 }}
                    animate={{ opacity: 1, y: 0 }}
                    exit={{ opacity: 0, y: -10 }}
                    transition={{ duration: 0.15 }}
                  >
                    <input
                      type="text"
                      placeholder="Enter a topic (e.g. 'Space')"
                      value={topic}
                      onChange={(e) => setTopic(e.target.value)}
                      className="w-full p-4 text-xl font-bold border-2 border-gray-200 rounded-2xl focus:border-theme-primary focus:ring-4 focus:ring-theme-primary/20 outline-none transition-all placeholder:font-medium text-center"
                      disabled={isLoading}
                    />
                  </motion.div>
                ) : (
                  <motion.div
                    key="document"
                    initial={{ opacity: 0, y: 10 }}
                    animate={{ opacity: 1, y: 0 }}
                    exit={{ opacity: 0, y: -10 }}
                    transition={{ duration: 0.15 }}
                    className="space-y-3"
                  >
                    <div
                      onDrop={handleDrop}
                      onDragOver={handleDragOver}
                      onDragLeave={handleDragLeave}
                      onClick={() => document.getElementById('file-upload')?.click()}
                      className={`border-2 border-dashed rounded-2xl p-4 text-center cursor-pointer transition-all ${
                        isDragging 
                          ? 'border-theme-primary bg-theme-primary/5 scale-[1.02]' 
                          : selectedFiles.length > 0
                            ? 'border-theme-primary/50 bg-theme-primary/5'
                            : 'border-gray-300 hover:border-gray-400 hover:bg-gray-50'
                      }`}
                    >
                      <input
                        id="file-upload"
                        type="file"
                        multiple
                        className="hidden"
                        onChange={handleFileSelect}
                        accept=".pdf,.txt,.md,.docx,.pptx,.xlsx,.odt,.odp,.ods,.rtf,.jpg,.jpeg,.png,.gif,.webp"
                      />
                      
                      <div className="space-y-2">
                        <Upload className={`mx-auto ${isDragging ? 'text-theme-primary' : 'text-gray-400'}`} size={28} />
                        <p className="text-sm font-bold text-gray-600">
                          {isDragging ? 'Drop files here' : 'Drop files or click to browse'}
                        </p>
                        <p className="text-xs text-gray-400">PDF, DOCX, PPTX, XLSX, TXT, Images</p>
                      </div>
                    </div>
                    
                    {selectedFiles.length > 0 && (
                      <div className="space-y-2">
                        <div className="flex justify-between items-center">
                          <span className="text-sm font-bold text-gray-600">{selectedFiles.length} file{selectedFiles.length > 1 ? 's' : ''} selected</span>
                          <button
                            type="button"
                            onClick={(e) => {
                              e.stopPropagation();
                              clearAllFiles();
                            }}
                            className="text-xs font-bold text-gray-400 hover:text-red-500 transition-colors"
                          >
                            Clear all
                          </button>
                        </div>
                        <div className="max-h-32 overflow-y-auto space-y-1.5">
                          {selectedFiles.map((file, index) => (
                            <div key={index} className="flex items-center justify-between bg-white p-2 rounded-lg shadow-sm">
                              <div className="flex items-center gap-2 overflow-hidden text-left">
                                <div className="p-1.5 bg-theme-primary/10 rounded">
                                  {file.type.startsWith('image/') ? (
                                    <Image size={14} className="text-theme-primary" />
                                  ) : (
                                    <FileText size={14} className="text-theme-primary" />
                                  )}
                                </div>
                                <span className="text-xs font-medium text-gray-700 truncate max-w-[180px]">{file.name}</span>
                              </div>
                              <button
                                type="button"
                                onClick={(e) => {
                                  e.stopPropagation();
                                  removeFile(index);
                                }}
                                className="p-1 hover:bg-gray-100 rounded text-gray-400 hover:text-red-500 transition-colors"
                              >
                                <X size={14} />
                              </button>
                            </div>
                          ))}
                        </div>
                      </div>
                    )}
                    
                    {showOcrOption && (
                      <label className="flex items-center gap-3 p-3 bg-gray-50 rounded-xl cursor-pointer hover:bg-gray-100 transition-colors">
                        <div className="relative">
                          <input
                            type="checkbox"
                            checked={useOcr}
                            onChange={(e) => setUseOcr(e.target.checked)}
                            className="sr-only peer"
                          />
                          <div className="w-10 h-6 bg-gray-300 rounded-full peer-checked:bg-theme-primary transition-colors"></div>
                          <div className="absolute left-1 top-1 w-4 h-4 bg-white rounded-full peer-checked:translate-x-4 transition-transform"></div>
                        </div>
                        <div className="flex items-center gap-2">
                          <ScanText size={18} className="text-gray-500" />
                          <span className="text-sm font-bold text-gray-600">
                            {hasImageFile && !hasDocumentFile ? 'Extract text with OCR' : 'OCR embedded images'}
                          </span>
                        </div>
                      </label>
                    )}
                  </motion.div>
                )}
              </AnimatePresence>

              <div className="space-y-2 pt-2">
                <div className="flex justify-between items-center text-sm font-bold text-gray-500">
                  <span>Questions</span>
                  <span className="bg-gray-100 text-gray-600 px-2 py-0.5 rounded-lg text-xs">{questionCount}</span>
                </div>
                <input
                  type="range"
                  min="5"
                  max="30"
                  value={questionCount}
                  onChange={(e) => setQuestionCount(Number(e.target.value))}
                  className="w-full accent-theme-primary h-2 bg-gray-200 rounded-lg appearance-none cursor-pointer"
                />
              </div>

              <button
                type="submit"
                disabled={isLoading || !canGenerate}
                className="w-full bg-[#333] text-white py-4 rounded-2xl text-xl font-black shadow-[0_6px_0_#000] active:shadow-none active:translate-y-[6px] transition-all hover:bg-black flex items-center justify-center gap-3 disabled:opacity-50 disabled:cursor-not-allowed"
              >
                {isLoading ? (
                  <Loader2 className="animate-spin" />
                ) : (
                  <>
                    <BrainCircuit size={24} /> 
                    {generateMode === 'document' ? 'Generate from Document' : 'Generate Quiz'}
                  </>
                )}
              </button>
            </form>
            
            <div className="relative flex py-2 items-center opacity-50">
                <div className="flex-grow border-t-2 border-gray-300"></div>
                <span className="flex-shrink mx-4 text-gray-400 font-bold">OR</span>
                <div className="flex-grow border-t-2 border-gray-300"></div>
            </div>

            <button 
              onClick={onCreateManual}
              className="w-full bg-white border-2 border-theme-primary text-theme-primary py-3 rounded-2xl text-lg font-black hover:bg-theme-hover shadow-[0_4px_0_var(--theme-primary)] active:shadow-none active:translate-y-[4px] transition-all flex items-center justify-center gap-2"
            >
               <PenTool size={20} /> Create Manually
            </button>

            {auth.isAuthenticated && (
              <button 
                onClick={() => setLibraryOpen(true)}
                className="w-full bg-gray-100 text-gray-600 py-3 rounded-2xl text-lg font-black hover:bg-gray-200 shadow-[0_4px_0_#d1d5db] active:shadow-none active:translate-y-[4px] transition-all flex items-center justify-center gap-2"
              >
                <BookOpen size={20} /> My Quizzes
              </button>
            )}
          </div>
        ) : (
            <form onSubmit={handleJoinSubmit} className="space-y-4">
              <input
                type="text"
                placeholder="Game PIN"
                value={pin}
                onChange={(e) => setPin(e.target.value)}
                className="w-full p-4 text-xl font-bold border-2 border-gray-200 rounded-2xl focus:border-theme-primary focus:ring-4 focus:ring-theme-primary/20 outline-none text-center"
              />
              <input
                type="text"
                placeholder="Nickname"
                value={name}
                onChange={(e) => setName(e.target.value)}
                className="w-full p-4 text-xl font-bold border-2 border-gray-200 rounded-2xl focus:border-theme-primary focus:ring-4 focus:ring-theme-primary/20 outline-none text-center"
              />
              <button
                type="submit"
                disabled={!pin.trim() || !name.trim()}
                className="w-full bg-[#333] text-white py-4 rounded-2xl text-xl font-black shadow-[0_6px_0_#000] active:shadow-none active:translate-y-[6px] transition-all hover:bg-black flex items-center justify-center gap-3"
              >
                <Play fill="currentColor" /> Join Game
              </button>
            </form>
        )}
        
        {error && (
          <motion.div initial={{ height: 0 }} animate={{ height: 'auto' }} className="overflow-hidden mt-4">
            <p className="text-red-500 font-bold bg-red-50 p-3 rounded-xl border-2 border-red-100">{error}</p>
          </motion.div>
        )}
      </motion.div>

      <QuizLibrary
        isOpen={libraryOpen}
        onClose={() => setLibraryOpen(false)}
        quizzes={quizzes}
        loading={libraryLoading}
        loadingQuizId={loadingQuizId}
        deletingQuizId={deletingQuizId}
        error={libraryError}
        onLoadQuiz={handleLoadQuiz}
        onDeleteQuiz={deleteQuiz}
        onRetry={retryLibrary}
      />

      <DefaultConfigModal
        isOpen={defaultConfigOpen}
        onClose={() => {
          setDefaultConfigOpen(false);
          setEditingDefaultConfig(null);
        }}
        config={editingDefaultConfig || defaultConfig}
        onChange={setEditingDefaultConfig}
        onSave={async () => {
          if (editingDefaultConfig) {
            await saveDefaultConfig(editingDefaultConfig);
            setDefaultConfigOpen(false);
            setEditingDefaultConfig(null);
          }
        }}
        saving={savingConfig}
      />
    </div>
  );
};