import React, { useState, useEffect } from 'react';
import { supabase } from '../supabaseClient';

interface ProblemFile {
  id: string;
  name: string;
  pattern: string;
  difficulty: string;
  reference_code: string;
  description: string | null;
  box_level: number | null;
  next_review: string | null;
  last_reviewed: string | null;
  times_correct: number;
  total_attempts: number;
}

interface FileExplorerProps {
  onSetWallpaper: (url: string) => void;
  activeWallpaperUrl: string;
}

const WALLPAPER_PRESETS = [
  {
    name: 'Retro Arcade Grid.img',
    url: 'https://lh3.googleusercontent.com/aida-public/AB6AXuAMJHVhhK8_G7F8sbhn8F7w4AZWXb1O_-HLKvrZ_fJlbUVMcVuxxEOO_LlOh8qIwtAn2KvzvCwzmtNLLEZ5uYkCEsx8ZWXJR609qgSMRSX8LBBeskk4VzVXnyzsgIKCedeV2PvGxJlUNnledcWKCXqG9egQi8dgTcA7C2z82QyM73KZ4s7ZRzZHNupuQt1ocfcMl9E_x1PWFRridl751LIpyGZgednS5CmVw2rZvFc_tbp2QTxgVHJ_59myEBmy6aajbO06AhkKmCvI',
    desc: 'Default AlgoSpaced purple grid and pixel theme background.'
  },
  {
    name: 'Classic Board Logo.img',
    url: 'https://lh3.googleusercontent.com/aida-public/AB6AXuD2tUGA2d7QiNyajDAWYK183zhNTgtAZpOXK3E9wRvHGs-t6ykWt9uPScYe_fziWzQI0pREcY_ThI341WvGMusyYmnAkagfuwx6wubIs1ES68DO8CCNAlcHcb2zOUU4MJeYuhWDy1uYRqyGYjIaDUqfgNWk2vm4WzwRqoorn2dxtZ6QdJhEKbXjG8fG9chkkvr68qJf0fLUL6bIqBXZg2FJ30S7zS3oZ4IZsug-wLyRYuJ4Gu_86snNUo1whNrBdZm5OMREfc9sLbwJ',
    desc: 'System info and arcade machine diagram wallpaper.'
  },
  {
    name: 'Terminal Console Icon.img',
    url: 'https://lh3.googleusercontent.com/aida-public/AB6AXuA2AvcQ2oKWP8AJ8yR5nF82LLDEH1FKySUK-npnqEjvJ6Cs9xp8joCwH7x43oTCAC5xhO2rQdYzka3B6u72FNbdxMnsv3WJLye3bKochu8AnnRlS3szfYSaj724sYsiZo4n8G-oWqvl7C0rOGaDaU2nRH1xXmW2PBi6L2NryTsUaTCVZQKTKBBNNEOig5kh7B52e-iIuj2PTzaSjF9ebp6gMuCnBtJT8Sxo5Qsmvfm-t2U5r_qQpRiYj--Ut41T7NTh-tHgs4S4kBvz',
    desc: 'Dark retro CRT terminal screen layout.'
  },
  {
    name: 'Synthwave Sunset Grid.img',
    url: 'https://images.unsplash.com/photo-1550745165-9bc0b252726f?q=80&w=1000&auto=format&fit=crop',
    desc: 'Glowing neon grids and vector mountains styling.'
  },
  {
    name: 'Matrix Code Rain.img',
    url: 'https://images.unsplash.com/photo-1526374965328-7f61d4dc18c5?q=80&w=1000&auto=format&fit=crop',
    desc: 'Falling green digital characters rain.'
  }
];

export default function FileExplorer({ onSetWallpaper, activeWallpaperUrl }: FileExplorerProps) {
  const [currentPath, setCurrentPath] = useState<string[]>(['C:']);
  const [problems, setProblems] = useState<ProblemFile[]>([]);
  const [loading, setLoading] = useState(true);
  const [selectedItem, setSelectedItem] = useState<string | null>(null);

  // Dynamic wallpapers list merging presets and custom wallpaper from localStorage
  const wallpapersList = React.useMemo(() => {
    const list = [...WALLPAPER_PRESETS];
    const customUrl = localStorage.getItem('customWallpaperUrl');
    const customName = localStorage.getItem('customWallpaperName') || 'Custom Wallpaper.img';
    if (customUrl) {
      const exists = list.some(p => p.url === customUrl);
      if (!exists) {
        list.push({
          name: customName,
          url: customUrl,
          desc: 'User uploaded custom background wallpaper.'
        });
      }
    }
    return list;
  }, [activeWallpaperUrl]);

  // Search & Filter state
  const [searchQuery, setSearchQuery] = useState('');
  const [difficultyFilter, setDifficultyFilter] = useState('All');
  const [patternFilter, setPatternFilter] = useState('All');

  // Drag & Drop state
  const [dragOver, setDragOver] = useState(false);

  // New File Creation state
  const [isCreateModalOpen, setIsCreateModalOpen] = useState(false);
  const [newFileName, setNewFileName] = useState('');
  const [newFilePattern, setNewFilePattern] = useState('');
  const [newFileDifficulty, setNewFileDifficulty] = useState('Medium');
  const [newFileCode, setNewFileCode] = useState('');
  const [newFileDescription, setNewFileDescription] = useState('');
  const [createError, setCreateError] = useState('');
  const [creating, setCreating] = useState(false);

  // Previewer Modal state
  const [previewFile, setPreviewFile] = useState<ProblemFile | null>(null);
  const [modalTab, setModalTab] = useState<'description' | 'code' | 'properties'>('description');
  const [isEditing, setIsEditing] = useState(false);
  const [editedCode, setEditedCode] = useState('');
  const [editedDescription, setEditedDescription] = useState('');
  const [saving, setSaving] = useState(false);
  const [saveSuccess, setSaveSuccess] = useState(false);
  const [copied, setCopied] = useState(false);

  const fetchProblems = async () => {
    setLoading(true);
    try {
      const { data: { session } } = await supabase.auth.getSession();
      if (!session) return;
      
      const res = await fetch(`${import.meta.env.VITE_API_BASE_URL}/api/explorer/problems`, {
        headers: { 'Authorization': `Bearer ${session.access_token}` }
      });
      if (res.ok) {
        const data = await res.json();
        setProblems(data);
      }
    } catch (err) {
      console.error('Failed to fetch explorer files:', err);
    } finally {
      setLoading(false);
    }
  };

  useEffect(() => {
    fetchProblems();
  }, []);

  const navigateTo = (folder: string) => {
    setCurrentPath(['C:', folder]);
    setSelectedItem(null);
  };

  const navigateUp = () => {
    if (currentPath.length > 1) {
      setCurrentPath(['C:']);
      setSelectedItem(null);
    }
  };

  // ZIP Solutions Exporter via Backend stream
  const handleExportZip = async () => {
    try {
      const { data: { session } } = await supabase.auth.getSession();
      if (!session) return;
      
      const res = await fetch(`${import.meta.env.VITE_API_BASE_URL}/api/explorer/export`, {
        headers: { 'Authorization': `Bearer ${session.access_token}` }
      });
      if (res.ok) {
        const blob = await res.blob();
        const url = window.URL.createObjectURL(blob);
        const a = document.createElement('a');
        a.href = url;
        a.download = 'algospaced_solutions.zip';
        document.body.appendChild(a);
        a.click();
        document.body.removeChild(a);
        window.URL.revokeObjectURL(url);
      }
    } catch (err) {
      console.error('Failed to download solutions ZIP:', err);
    }
  };

  // Handle Save Solution Code changes
  const handleSaveSolution = async () => {
    if (!previewFile) return;
    setSaving(true);
    setSaveSuccess(false);
    try {
      const { data: { session } } = await supabase.auth.getSession();
      if (!session) return;

      const res = await fetch(`${import.meta.env.VITE_API_BASE_URL}/api/explorer/problems/${previewFile.id}`, {
        method: 'PUT',
        headers: {
          'Content-Type': 'application/json',
          'Authorization': `Bearer ${session.access_token}`
        },
        body: JSON.stringify({
          name: previewFile.name,
          pattern: previewFile.pattern,
          difficulty: previewFile.difficulty,
          reference_code: editedCode,
          description: editedDescription
        })
      });
      if (res.ok) {
        setSaveSuccess(true);
        setIsEditing(false);
        // Refresh local problems list
        const updated = problems.map(p => p.id === previewFile.id ? { ...p, reference_code: editedCode, description: editedDescription } : p);
        setProblems(updated);
        setPreviewFile({ ...previewFile, reference_code: editedCode, description: editedDescription });
        setTimeout(() => setSaveSuccess(false), 2000);
      }
    } catch (err) {
      console.error('Failed to update solution code:', err);
    } finally {
      setSaving(false);
    }
  };

  // Create New Problem
  const handleCreateProblem = async (e: React.FormEvent) => {
    e.preventDefault();
    if (!newFileName.trim()) {
      setCreateError('Problem name cannot be empty');
      return;
    }
    setCreating(true);
    setCreateError('');
    try {
      const { data: { session } } = await supabase.auth.getSession();
      if (!session) return;

      const res = await fetch(`${import.meta.env.VITE_API_BASE_URL}/api/explorer/problems/create`, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
          'Authorization': `Bearer ${session.access_token}`
        },
        body: JSON.stringify({
          name: newFileName.trim(),
          pattern: newFilePattern.trim() || 'General',
          difficulty: newFileDifficulty,
          reference_code: newFileCode,
          description: newFileDescription
        })
      });

      const data = await res.json();
      if (res.ok && data.success) {
        setIsCreateModalOpen(false);
        setNewFileName('');
        setNewFilePattern('');
        setNewFileCode('');
        setNewFileDescription('');
        fetchProblems();
      } else {
        setCreateError(data.detail || 'Failed to create problem.');
      }
    } catch {
      setCreateError('Connection timed out.');
    } finally {
      setCreating(false);
    }
  };

  // Drag and Drop files parser
  const handleDragOver = (e: React.DragEvent) => {
    e.preventDefault();
    setDragOver(true);
  };

  const handleDragLeave = () => {
    setDragOver(false);
  };

  const handleDrop = async (e: React.DragEvent) => {
    e.preventDefault();
    setDragOver(false);
    const files = e.dataTransfer.files;
    if (files.length > 0) {
      const file = files[0];
      if (file.name.endsWith('.py')) {
        try {
          const text = await file.text();
          const guessedName = file.name
            .replace('.py', '')
            .replace(/_/g, ' ')
            .replace(/-/g, ' ');

          // Parse metadata tags if they exist inside script comments
          let pattern = 'General';
          let difficulty = 'Medium';

          const patternMatch = text.match(/#\s*Pattern:\s*(.+)/i);
          if (patternMatch) pattern = patternMatch[1].trim();

          const difficultyMatch = text.match(/#\s*Difficulty:\s*(.+)/i);
          if (difficultyMatch) {
            const val = difficultyMatch[1].trim();
            if (['Easy', 'Medium', 'Hard'].includes(val)) difficulty = val;
          }

          // Parse description: take all leading comment lines (excluding structural tags)
          const lines = text.split('\n');
          let descLines = [];
          for (let line of lines) {
            const trimmed = line.trim();
            if (trimmed.startsWith('#')) {
              if (trimmed.match(/#\s*(Pattern|Difficulty|Problem|Description):/i)) continue;
              descLines.push(trimmed.replace(/^#\s*/, ''));
            } else if (trimmed !== '') {
              break;
            }
          }
          const description = descLines.join('\n').trim();



          // Load into New File Creator modal
          setNewFileName(guessedName);
          setNewFilePattern(pattern);
          setNewFileDifficulty(difficulty);
          setNewFileCode(text);
          setNewFileDescription(description);
          setIsCreateModalOpen(true);
        } catch (err) {
          console.error('Failed to parse uploaded script:', err);
        }
      }
    }
  };

  const handleCopyCode = (text: string) => {
    navigator.clipboard.writeText(text);
    setCopied(true);
    setTimeout(() => setCopied(false), 2000);
  };

  const activeFolder = currentPath.length > 1 ? currentPath[1] : 'root';

  // Statistics calculation for the visualizer
  const totalProblems = problems.length;
  const completedSolutions = problems.filter(p => p.reference_code && p.reference_code.trim()).length;
  const completionPercent = totalProblems > 0 ? Math.round((completedSolutions / totalProblems) * 100) : 0;
  
  const boxCounts = { 1: 0, 2: 0, 3: 0, 4: 0, 5: 0 };
  problems.forEach(p => {
    if (p.box_level !== null && p.box_level !== undefined) {
      const lvl = p.box_level as 1|2|3|4|5;
      if (lvl >= 1 && lvl <= 5) boxCounts[lvl]++;
    }
  });

  // Extract unique patterns to populate filter dropdown dynamically
  const uniquePatterns = Array.from(new Set(problems.map(p => p.pattern).filter(Boolean)));

  // Filter solutions list
  const filteredProblems = problems.filter(p => {
    const matchesSearch = p.name.toLowerCase().includes(searchQuery.toLowerCase());
    const matchesDifficulty = difficultyFilter === 'All' || p.difficulty === difficultyFilter;
    const matchesPattern = patternFilter === 'All' || p.pattern === patternFilter;
    return matchesSearch && matchesDifficulty && matchesPattern;
  });

  return (
    <div className="w-full h-full bg-paper-white text-ink-black flex flex-col overflow-hidden text-xs md:text-sm font-sans select-none">
      
      {/* 1. Address Bar & Navigation */}
      <div className="bg-slate-200 border-b-[3px] border-ink-black p-2 flex items-center justify-between shrink-0">
        <div className="flex items-center gap-2 flex-1">
          <button
            onClick={navigateUp}
            disabled={currentPath.length === 1}
            className="w-7 h-7 bg-white border-2 border-ink-black flex items-center justify-center hover:bg-slate-100 disabled:opacity-40 disabled:cursor-not-allowed cursor-pointer active:translate-y-0.5"
            title="Up One Folder"
          >
            <span className="material-symbols-outlined text-[16px] font-bold">arrow_upward</span>
          </button>
          <div className="bg-white border-2 border-ink-black px-3 py-1 font-mono text-[10px] flex-1 max-w-[280px] truncate">
            {currentPath.join('\\')}
          </div>
        </div>

        {/* Action Link bar */}
        <div className="flex gap-3 text-[10px] font-bold pr-2 font-mono items-center">
          {activeFolder === 'Database_Codes' && (
            <>
              <button
                onClick={() => setIsCreateModalOpen(true)}
                className="text-blue-700 hover:underline cursor-pointer flex items-center gap-0.5"
              >
                <span className="material-symbols-outlined text-[12px] font-bold">add_box</span>
                NEW FILE
              </button>
              <span className="text-slate-400">|</span>
              <button
                onClick={handleExportZip}
                className="text-purple-700 hover:underline cursor-pointer flex items-center gap-0.5"
              >
                <span className="material-symbols-outlined text-[12px] font-bold">downloadzip</span>
                BACKUP (.ZIP)
              </button>
              <span className="text-slate-400">|</span>
            </>
          )}
          <span className="text-slate-500">
            {activeFolder === 'root' ? '2 Folder(s)' : activeFolder === 'Database_Codes' ? `${filteredProblems.length} of ${problems.length} item(s)` : `${wallpapersList.length} image(s)`}
          </span>
        </div>
      </div>

      {/* 2. Main Workspace Layout */}
      <div className="flex-1 flex overflow-hidden">
        
        {/* Left Side: Navigation Sidebar & Disk Stats Visualizer */}
        <aside className="w-1/3 border-r-[3px] border-ink-black bg-[#fdf8e1] p-3 overflow-y-auto custom-scrollbar flex flex-col gap-4 shrink-0">
          {/* Folders tree */}
          <div>
            <span className="text-[9px] font-arcade text-slate-500 block uppercase mb-1.5">Folders</span>
            <div className="space-y-1">
              <button
                onClick={() => setCurrentPath(['C:'])}
                className={`w-full text-left p-1.5 flex items-center gap-1.5 font-semibold border-2 border-transparent hover:bg-slate-100 rounded ${currentPath.length === 1 ? 'bg-white border-ink-black' : ''}`}
              >
                <span className="material-symbols-outlined text-[#855400] text-sm" style={{ fontVariationSettings: "'FILL' 1" }}>desktop_windows</span>
                <span>C: (Root)</span>
              </button>
              <div className="pl-4 space-y-1">
                <button
                  onClick={() => navigateTo('Database_Codes')}
                  className={`w-full text-left p-1.5 flex items-center gap-1.5 font-semibold border-2 border-transparent hover:bg-slate-100 rounded ${activeFolder === 'Database_Codes' ? 'bg-white border-ink-black' : ''}`}
                >
                  <span className="material-symbols-outlined text-yellow-600 text-sm" style={{ fontVariationSettings: "'FILL' 1" }}>folder</span>
                  <span className="truncate">Database_Codes</span>
                </button>
                <button
                  onClick={() => navigateTo('Wallpapers')}
                  className={`w-full text-left p-1.5 flex items-center gap-1.5 font-semibold border-2 border-transparent hover:bg-slate-100 rounded ${activeFolder === 'Wallpapers' ? 'bg-white border-ink-black' : ''}`}
                >
                  <span className="material-symbols-outlined text-yellow-600 text-sm" style={{ fontVariationSettings: "'FILL' 1" }}>folder</span>
                  <span className="truncate">Wallpapers</span>
                </button>
              </div>
            </div>
          </div>

          {/* Feature 5: Disk Stats Visualizer */}
          <div className="border-t-2 border-dashed border-slate-300 pt-3">
            <span className="text-[9px] font-arcade text-slate-500 block uppercase mb-2">System Statistics</span>
            
            <div className="space-y-3 font-sans text-[11px] font-bold text-slate-700">
              {/* Completion Rate ProgressBar */}
              <div className="space-y-1">
                <div className="flex justify-between text-[10px]">
                  <span>CODE COMPLETION:</span>
                  <span className="font-mono text-emerald-600">{completionPercent}%</span>
                </div>
                <div className="w-full h-4 bg-white border-2 border-ink-black overflow-hidden relative">
                  <div 
                    style={{ width: `${completionPercent}%` }} 
                    className="h-full bg-emerald-500 border-r-2 border-ink-black transition-all duration-500" 
                  />
                </div>
              </div>

              {/* Box Level Counts visual bar charts */}
              <div className="space-y-1.5 mt-2">
                <span className="text-[9px] uppercase text-slate-500 block">Leitner Distribution:</span>
                {([1, 2, 3, 4, 5] as const).map(boxNum => {
                  const count = boxCounts[boxNum];
                  const maxCount = Math.max(...Object.values(boxCounts), 1);
                  const barWidth = Math.max(8, Math.round((count / maxCount) * 100));

                  return (
                    <div key={boxNum} className="flex items-center gap-2">
                      <span className="w-9 font-mono text-[10px] text-slate-400">Box {boxNum}:</span>
                      <div className="flex-1 h-3 bg-white border border-ink-black overflow-hidden relative">
                        <div 
                          style={{ width: `${barWidth}%` }} 
                          className="h-full bg-[#0ea5e9] border-r border-ink-black transition-all" 
                        />
                      </div>
                      <span className="w-4 text-right font-mono text-[10px] text-slate-600">{count}</span>
                    </div>
                  );
                })}
              </div>
            </div>
          </div>
        </aside>

        {/* Right Side: Folder View Contents & Upload Area */}
        <main 
          onDragOver={handleDragOver}
          onDragLeave={handleDragLeave}
          onDrop={handleDrop}
          className={`flex-1 bg-white p-4 overflow-y-auto custom-scrollbar flex flex-col relative transition-all ${
            dragOver ? 'bg-blue-50 border-4 border-dashed border-blue-500 m-2' : ''
          }`}
        >
          {dragOver && (
            <div className="absolute inset-0 flex flex-col items-center justify-center text-blue-800 bg-white/80 pointer-events-none select-none z-[10] gap-2 font-sans font-bold">
              <span className="material-symbols-outlined text-5xl animate-bounce">upload_file</span>
              <div className="text-sm">DROP SOLUTIONS PYTHON SCRIPT (.PY) HERE</div>
              <p className="text-[10px] text-slate-400">Will load and parse file metadata for import</p>
            </div>
          )}

          {loading ? (
            <div className="flex-1 flex flex-col items-center justify-center font-arcade text-[8px] animate-pulse">
              READING SYSTEM DISK...
            </div>
          ) : (
            <>
              {/* Feature 2: Search and Filter Bar Header */}
              {activeFolder === 'Database_Codes' && (
                <div className="mb-4 bg-slate-50 border-[2px] border-ink-black p-2 flex flex-col gap-2 shrink-0 select-none">
                  <div className="flex gap-2">
                    {/* Search Field */}
                    <div className="flex-1 bg-white border border-slate-300 rounded px-2 py-1 flex items-center gap-1">
                      <span className="material-symbols-outlined text-slate-400 text-sm">search</span>
                      <input
                        type="text"
                        value={searchQuery}
                        onChange={(e) => setSearchQuery(e.target.value)}
                        className="w-full bg-transparent outline-none border-none p-0 text-[11px] focus:ring-0 font-sans"
                        placeholder="Search codes by name..."
                      />
                    </div>
                  </div>
                  <div className="flex gap-3 text-[10px] font-bold text-slate-600">
                    {/* Difficulty Filter */}
                    <div className="flex items-center gap-1">
                      <span>Diff:</span>
                      <select
                        value={difficultyFilter}
                        onChange={(e) => setDifficultyFilter(e.target.value)}
                        className="bg-white border border-slate-300 p-0.5 text-[9px] rounded font-sans cursor-pointer focus:ring-1 outline-none"
                      >
                        <option value="All">All</option>
                        <option value="Easy">Easy</option>
                        <option value="Medium">Medium</option>
                        <option value="Hard">Hard</option>
                      </select>
                    </div>
                    {/* Pattern Filter */}
                    <div className="flex items-center gap-1 flex-1">
                      <span>Pattern:</span>
                      <select
                        value={patternFilter}
                        onChange={(e) => setPatternFilter(e.target.value)}
                        className="bg-white border border-slate-300 p-0.5 text-[9px] rounded font-sans cursor-pointer max-w-[120px] focus:ring-1 outline-none truncate"
                      >
                        <option value="All">All</option>
                        {uniquePatterns.map(pat => (
                          <option key={pat} value={pat}>{pat}</option>
                        ))}
                      </select>
                    </div>
                  </div>
                </div>
              )}

              {/* Root Content View */}
              {activeFolder === 'root' && (
                <div className="grid grid-cols-2 gap-4">
                  <div
                    onDoubleClick={() => navigateTo('Database_Codes')}
                    onClick={() => setSelectedItem('codes')}
                    className={`flex flex-col items-center justify-center p-3 border-[3px] border-transparent hover:bg-slate-50 cursor-pointer rounded select-none ${selectedItem === 'codes' ? 'bg-yellow-50 border-dashed border-ink-black' : ''}`}
                  >
                    <span className="material-symbols-outlined text-5xl text-yellow-500" style={{ fontVariationSettings: "'FILL' 1" }}>folder</span>
                    <span className="font-bold text-center mt-2 text-xs">Database_Codes</span>
                    <span className="text-[9px] text-slate-400 mt-0.5">Synced solution files</span>
                  </div>
                  <div
                    onDoubleClick={() => navigateTo('Wallpapers')}
                    onClick={() => setSelectedItem('wallpapers')}
                    className={`flex flex-col items-center justify-center p-3 border-[3px] border-transparent hover:bg-slate-50 cursor-pointer rounded select-none ${selectedItem === 'wallpapers' ? 'bg-yellow-50 border-dashed border-ink-black' : ''}`}
                  >
                    <span className="material-symbols-outlined text-5xl text-yellow-500" style={{ fontVariationSettings: "'FILL' 1" }}>folder</span>
                    <span className="font-bold text-center mt-2 text-xs">Wallpapers</span>
                    <span className="text-[9px] text-slate-400 mt-0.5">Desktop wallpaper images</span>
                  </div>
                </div>
              )}

              {/* Database Codes Content View */}
              {activeFolder === 'Database_Codes' && (
                filteredProblems.length === 0 ? (
                  <div className="flex-1 flex flex-col items-center justify-center text-center text-slate-400 p-6 italic select-none">
                    <span className="material-symbols-outlined text-3xl mb-1">drafts</span>
                    No matching files found. Drag and drop a .py script to upload/create!
                  </div>
                ) : (
                  <div className="grid grid-cols-3 gap-2">
                    {filteredProblems.map((prob) => {
                      const cleanName = prob.name.replace(/\s+/g, '_');
                      const fileName = `${cleanName}.py`;
                      const isSelected = selectedItem === prob.id;

                      return (
                        <div
                          key={prob.id}
                          onClick={() => setSelectedItem(prob.id)}
                          onDoubleClick={() => {
                            setPreviewFile(prob);
                            setEditedCode(prob.reference_code || '');
                            setEditedDescription(prob.description || '');
                            setModalTab('description');
                            setIsEditing(false);
                          }}
                          className={`flex flex-col items-center p-2 border-[3px] border-transparent hover:bg-slate-50 cursor-pointer rounded select-none text-center ${isSelected ? 'bg-yellow-50 border-dashed border-ink-black' : ''}`}
                        >
                          <span className="material-symbols-outlined text-3xl text-emerald-600">article</span>
                          <span className="font-bold text-[10px] truncate w-full mt-1.5 leading-tight">{fileName}</span>
                          <span className="text-[8px] text-slate-400 font-bold uppercase mt-0.5">{prob.difficulty}</span>
                        </div>
                      );
                    })}
                  </div>
                )
              )}

              {/* Wallpapers Content View */}
              {activeFolder === 'Wallpapers' && (
                <div className="grid grid-cols-2 gap-3 select-none">
                  {wallpapersList.map((paper) => {
                    const isSelected = selectedItem === paper.name;
                    const isActive = activeWallpaperUrl === paper.url;

                    return (
                      <div
                        key={paper.name}
                        onClick={() => setSelectedItem(paper.name)}
                        className={`border-[3px] p-2 flex flex-col cursor-pointer bg-slate-50 relative hover:bg-slate-100 ${isSelected ? 'border-ink-black bg-yellow-50 shadow-[2px_2px_0_0_#1E293B]' : 'border-slate-300'}`}
                      >
                        <div className="aspect-video w-full border border-slate-300 overflow-hidden bg-black shrink-0 relative">
                          <img src={paper.url} alt={paper.name} className="w-full h-full object-cover select-none" />
                          {isActive && (
                            <div className="absolute top-1 right-1 bg-green-500 text-white rounded-full w-5 h-5 flex items-center justify-center border border-white" title="Active Wallpaper">
                              <span className="material-symbols-outlined text-[12px] font-extrabold">check</span>
                            </div>
                          )}
                        </div>
                        <span className="font-bold text-[10px] mt-1.5 truncate">{paper.name}</span>
                        <p className="text-[8px] text-slate-400 font-sans leading-tight mt-0.5 line-clamp-2">{paper.desc}</p>
                        
                        {isSelected && (
                          <button
                            onClick={(e) => {
                              e.stopPropagation();
                              onSetWallpaper(paper.url);
                              localStorage.setItem('desktopWallpaperUrl', paper.url);
                            }}
                            className="mt-2 w-full py-1 bg-highlight-pink text-white border-2 border-ink-black font-window-title font-bold text-[9px] hover:bg-pink-400 shadow-[1px_1px_0px_rgba(0,0,0,1)] active:translate-y-0.5 active:shadow-none transition-all text-center cursor-pointer"
                          >
                            APPLY BACKGROUND
                          </button>
                        )}
                      </div>
                    );
                  })}
                </div>
              )}
            </>
          )}
        </main>
      </div>

      {/* Feature 3 & 1: Two-Tab File Previewer & Editor Inspector Modal */}
      {previewFile && (
        <div className="absolute inset-0 bg-black/60 z-[999] flex items-center justify-center p-4">
          <div className="w-[90%] h-[90%] bg-paper-white border-[4px] border-ink-black shadow-[6px_6px_0px_0px_#1E293B] flex flex-col overflow-hidden animate-scale-up text-ink-black">
            
            {/* Modal Title bar */}
            <div className="bg-emerald-600 text-white p-2 border-b-[3px] border-ink-black flex justify-between items-center shrink-0 select-none">
              <div className="flex items-center gap-1.5">
                <span className="material-symbols-outlined text-sm">article</span>
                <span className="font-window-title font-bold text-xs">{previewFile.name.replace(/\s+/g, '_')}.py</span>
              </div>
              <button
                onClick={() => setPreviewFile(null)}
                className="bg-white text-ink-black border-[2px] border-ink-black w-5 h-5 flex items-center justify-center font-bold hover:bg-red-500 hover:text-white cursor-pointer"
              >
                X
              </button>
            </div>

            {/* Triple Tab selectors */}
            <div className="bg-slate-200 border-b-2 border-ink-black flex shrink-0 select-none">
              <button
                onClick={() => setModalTab('description')}
                className={`px-4 py-2 border-r-2 border-ink-black font-bold text-[11px] cursor-pointer ${modalTab === 'description' ? 'bg-white translate-y-[2px]' : 'bg-slate-300 hover:bg-slate-100'}`}
              >
                PROBLEM DESCRIPTION
              </button>
              <button
                onClick={() => setModalTab('code')}
                className={`px-4 py-2 border-r-2 border-ink-black font-bold text-[11px] cursor-pointer ${modalTab === 'code' ? 'bg-white translate-y-[2px]' : 'bg-slate-300 hover:bg-slate-100'}`}
              >
                CODE VIEW & EDIT
              </button>
              <button
                onClick={() => setModalTab('properties')}
                className={`px-4 py-2 border-r-2 border-ink-black font-bold text-[11px] cursor-pointer ${modalTab === 'properties' ? 'bg-white translate-y-[2px]' : 'bg-slate-300 hover:bg-slate-100'}`}
              >
                LEITNER PROPERTIES
              </button>
            </div>

            {/* TAB CONTENT: Problem Description */}
            {modalTab === 'description' && (
              <div className="flex-1 flex flex-col overflow-hidden bg-slate-900 relative">
                {isEditing ? (
                  <textarea
                    value={editedDescription}
                    onChange={(e) => setEditedDescription(e.target.value)}
                    className="flex-1 w-full bg-slate-950 text-[#4ADE80] font-mono p-4 outline-none border-none text-xs leading-relaxed resize-none custom-scrollbar"
                    placeholder="Enter problem description / question body here..."
                    spellCheck="false"
                  />
                ) : (
                  <div className="flex-1 p-4 bg-slate-900 text-[#4ADE80] font-sans text-xs leading-relaxed overflow-y-auto custom-scrollbar select-text">
                    <div className="whitespace-pre-wrap font-semibold">{previewFile.description || 'No description provided for this problem.'}</div>
                  </div>
                )}

                {/* Edit indicators */}
                {isEditing && (
                  <div className="absolute top-2 right-2 bg-yellow-400 text-ink-black border border-ink-black px-2 py-0.5 text-[9px] font-bold select-none animate-pulse">
                    EDIT MODE ACTIVE
                  </div>
                )}
              </div>
            )}

            {/* TAB CONTENT: Code preview & editing */}
            {modalTab === 'code' && (
              <div className="flex-1 flex flex-col overflow-hidden bg-slate-900 relative">
                {isEditing ? (
                  <textarea
                    value={editedCode}
                    onChange={(e) => setEditedCode(e.target.value)}
                    className="flex-1 w-full bg-slate-950 text-[#4ADE80] font-mono p-4 outline-none border-none text-xs leading-relaxed resize-none custom-scrollbar"
                    spellCheck="false"
                  />
                ) : (
                  <textarea
                    readOnly
                    value={previewFile.reference_code || '# Write your solution here.'}
                    className="flex-1 w-full bg-slate-900 text-[#4ADE80] font-mono p-4 outline-none border-none text-xs leading-relaxed resize-none custom-scrollbar"
                    spellCheck="false"
                  />
                )}

                {/* Edit indicators */}
                {isEditing && (
                  <div className="absolute top-2 right-2 bg-yellow-400 text-ink-black border border-ink-black px-2 py-0.5 text-[9px] font-bold select-none animate-pulse">
                    EDIT MODE ACTIVE
                  </div>
                )}
              </div>
            )}

            {/* TAB CONTENT: Leitner properties */}
            {modalTab === 'properties' && (
              <div className="flex-1 p-6 overflow-y-auto custom-scrollbar bg-slate-50 font-sans leading-relaxed select-text flex flex-col gap-4">
                <h3 className="font-arcade text-[10px] border-b border-slate-300 pb-1 text-slate-500">Card Diagnostics</h3>
                
                <div className="grid grid-cols-2 gap-4">
                  <div className="border-[3px] border-ink-black bg-white p-3 space-y-2">
                    <span className="text-[9px] font-arcade text-[#0ea5e9] block">Scheduling Status</span>
                    <div>Leitner Combo Box: <span className="font-mono font-bold text-lg text-sky-600">{previewFile.box_level || 'N/A (Box 1)'}</span></div>
                    <div>Next Review Date: <span className="font-mono text-xs font-semibold">{previewFile.next_review ? new Date(previewFile.next_review).toLocaleString() : 'N/A (Due)'}</span></div>
                    <div>Last Reviewed: <span className="font-mono text-xs font-semibold">{previewFile.last_reviewed ? new Date(previewFile.last_reviewed).toLocaleDateString() : 'Never'}</span></div>
                  </div>

                  <div className="border-[3px] border-ink-black bg-white p-3 space-y-2">
                    <span className="text-[9px] font-arcade text-emerald-600 block">Performance History</span>
                    <div>Total Attempts: <span className="font-mono font-bold text-sm">{previewFile.total_attempts}</span></div>
                    <div>Times Correct: <span className="font-mono font-bold text-sm text-green-600">{previewFile.times_correct}</span></div>
                    <div>Success Ratio: <span className="font-mono font-bold text-sm text-purple-700">
                      {previewFile.total_attempts > 0 ? `${Math.round((previewFile.times_correct / previewFile.total_attempts) * 100)}%` : '0%'}
                    </span></div>
                  </div>
                </div>

                <div className="border-[3px] border-ink-black bg-white p-3 space-y-1.5 text-xs font-semibold">
                  <span className="text-[9px] font-arcade text-slate-400 block">Properties</span>
                  <div>File ID: <span className="font-mono text-[10px] text-slate-500">{previewFile.id}</span></div>
                  <div>Logical Pattern: <span className="text-blue-600">{previewFile.pattern}</span></div>
                  <div>Difficulty Tag: <span className="uppercase">{previewFile.difficulty}</span></div>
                </div>
              </div>
            )}

            {/* Modal Footer controls */}
            <div className="p-3 bg-slate-100 border-t-[3px] border-ink-black flex justify-between items-center shrink-0 select-none">
              <div>
                {saveSuccess && (
                  <span className="text-green-600 font-bold text-xs animate-pulse">✓ Solution saved!</span>
                )}
              </div>
              <div className="flex gap-2">
                {(modalTab === 'code' || modalTab === 'description') && (
                  isEditing ? (
                    <>
                      <button
                        onClick={() => {
                          setEditedCode(previewFile.reference_code || '');
                          setEditedDescription(previewFile.description || '');
                          setIsEditing(false);
                        }}
                        className="px-3 py-1.5 bg-white hover:bg-slate-50 text-ink-black border-2 border-ink-black font-bold text-xs cursor-pointer"
                      >
                        CANCEL
                      </button>
                      <button
                        disabled={saving}
                        onClick={handleSaveSolution}
                        className="px-3 py-1.5 bg-[#4ADE80] hover:bg-emerald-400 text-ink-black border-2 border-ink-black font-bold text-xs cursor-pointer shadow-[2px_2px_0px_rgba(0,0,0,1)] active:translate-y-0.5 active:shadow-none"
                      >
                        {saving ? 'SAVING...' : 'SAVE CHANGES'}
                      </button>
                    </>
                  ) : (
                    <button
                      onClick={() => setIsEditing(true)}
                      className="px-3 py-1.5 bg-yellow-400 hover:bg-yellow-300 text-ink-black border-2 border-ink-black font-bold text-xs cursor-pointer shadow-[2px_2px_0px_rgba(0,0,0,1)] active:translate-y-0.5 active:shadow-none flex items-center gap-1"
                    >
                      <span className="material-symbols-outlined text-sm">edit</span>
                      EDIT FILE
                    </button>
                  )
                )}

                <button
                  onClick={() => handleCopyCode(isEditing ? editedCode : previewFile.reference_code)}
                  className="px-3 py-1.5 bg-[#ffcc00] hover:bg-yellow-300 text-ink-black border-2 border-ink-black font-bold text-xs shadow-[2px_2px_0px_rgba(0,0,0,1)] active:translate-y-0.5 active:shadow-none cursor-pointer flex items-center gap-1"
                >
                  <span className="material-symbols-outlined text-sm">content_copy</span>
                  {copied ? 'COPIED!' : 'COPY CODE'}
                </button>
                <button
                  onClick={() => setPreviewFile(null)}
                  className="px-3 py-1.5 bg-white hover:bg-slate-50 text-ink-black border-2 border-ink-black font-bold text-xs shadow-[2px_2px_0px_rgba(0,0,0,1)] active:translate-y-0.5 active:shadow-none cursor-pointer"
                >
                  CLOSE
                </button>
              </div>
            </div>
          </div>
        </div>
      )}

      {/* Feature 1: New File Creator Modal Dialog */}
      {isCreateModalOpen && (
        <div className="absolute inset-0 bg-black/60 z-[999] flex items-center justify-center p-4 select-none">
          <div className="w-[80%] max-w-[500px] bg-paper-white border-[4px] border-ink-black shadow-[6px_6px_0px_0px_#1E293B] flex flex-col overflow-hidden animate-scale-up text-ink-black font-sans">
            
            {/* Modal Header */}
            <div className="bg-primary-purple text-white p-2.5 border-b-[3px] border-ink-black flex justify-between items-center font-bold">
              <span className="font-window-title text-xs">CREATE NEW SOLUTION FILE</span>
              <button
                onClick={() => setIsCreateModalOpen(false)}
                className="bg-white text-ink-black border-[2px] border-ink-black w-5 h-5 flex items-center justify-center font-bold hover:bg-red-500 hover:text-white cursor-pointer"
              >
                X
              </button>
            </div>

            {/* Modal Body form */}
            <form onSubmit={handleCreateProblem} className="p-4 space-y-3 flex-1 overflow-y-auto custom-scrollbar">
              {createError && (
                <div className="p-2 border-2 border-red-500 bg-red-50 text-red-800 text-[10px] font-mono leading-relaxed">
                  {createError}
                </div>
              )}

              {/* Problem Name */}
              <div className="flex flex-col gap-1">
                <label className="text-[10px] font-bold text-slate-500 uppercase">Problem Name:</label>
                <input
                  type="text"
                  required
                  value={newFileName}
                  onChange={(e) => setNewFileName(e.target.value)}
                  placeholder="e.g. Two Sum"
                  className="bg-white border-2 border-ink-black p-1.5 text-xs outline-none focus:ring-1 focus:ring-primary-purple font-semibold"
                />
              </div>

              {/* Logical Pattern Category */}
              <div className="flex flex-col gap-1">
                <label className="text-[10px] font-bold text-slate-500 uppercase">Pattern Category:</label>
                <input
                  type="text"
                  value={newFilePattern}
                  onChange={(e) => setNewFilePattern(e.target.value)}
                  placeholder="e.g. Sliding Window"
                  className="bg-white border-2 border-ink-black p-1.5 text-xs outline-none focus:ring-1 focus:ring-primary-purple font-semibold"
                />
              </div>

              {/* Difficulty Selection */}
              <div className="flex flex-col gap-1">
                <label className="text-[10px] font-bold text-slate-500 uppercase">Difficulty:</label>
                <select
                  value={newFileDifficulty}
                  onChange={(e) => setNewFileDifficulty(e.target.value)}
                  className="bg-white border-2 border-ink-black p-1.5 text-xs outline-none focus:ring-1 focus:ring-primary-purple font-bold cursor-pointer"
                >
                  <option value="Easy">Easy</option>
                  <option value="Medium">Medium</option>
                  <option value="Hard">Hard</option>
                </select>
              </div>

              {/* Problem Description */}
              <div className="flex flex-col gap-1">
                <label className="text-[10px] font-bold text-slate-500 uppercase">Problem Description:</label>
                <textarea
                  value={newFileDescription}
                  onChange={(e) => setNewFileDescription(e.target.value)}
                  placeholder="e.g. Given an array of integers, return indices of the two numbers such that they add up to a specific target."
                  className="bg-white border-2 border-ink-black p-1.5 text-xs outline-none focus:ring-1 focus:ring-primary-purple font-semibold h-[70px] resize-none"
                />
              </div>

              {/* Solution Code */}
              <div className="flex flex-col gap-1">
                <label className="text-[10px] font-bold text-slate-500 uppercase">Reference Python Code:</label>
                <textarea
                  value={newFileCode}
                  onChange={(e) => setNewFileCode(e.target.value)}
                  placeholder="def solve():\n    pass"
                  className="bg-slate-900 text-[#4ADE80] font-mono p-2 border-2 border-ink-black rounded outline-none h-[120px] text-xs leading-relaxed resize-none"
                />
              </div>

              {/* Action Buttons */}
              <div className="pt-3 border-t border-slate-200 flex justify-end gap-3 font-semibold">
                <button
                  type="button"
                  onClick={() => setIsCreateModalOpen(false)}
                  className="px-3 py-1.5 bg-white hover:bg-slate-50 border-2 border-ink-black text-xs cursor-pointer"
                >
                  CANCEL
                </button>
                <button
                  type="submit"
                  disabled={creating}
                  className="px-3 py-1.5 bg-primary-purple text-white border-2 border-ink-black text-xs cursor-pointer shadow-[2px_2px_0px_rgba(0,0,0,1)] active:translate-y-0.5 active:shadow-none"
                >
                  {creating ? 'CREATING...' : 'ADD SOLUTION'}
                </button>
              </div>
            </form>
          </div>
        </div>
      )}
    </div>
  );
}