import { useState, useMemo } from 'react';
import {
  FileText,
  FileCode2,
  Table2,
  Image as ImageIcon,
  Download,
  Copy,
  ChevronLeft,
  File,
} from 'lucide-react';

// ---------------------------------------------------------------------------
// Types
// ---------------------------------------------------------------------------

export interface ArtifactFile {
  id: string;
  name: string;
  type: 'markdown' | 'code' | 'table' | 'image' | 'text';
  content: string;
  language?: string;
  createdAt: Date;
  sourceStepId?: string; // Links to ToolCallStep that created this artifact
}

interface ArtifactPanelProps {
  artifacts: ArtifactFile[];
  selectedId?: string | null;
  onSelect: (id: string) => void;
  onClose?: () => void;
  className?: string;
}

// ---------------------------------------------------------------------------
// Helpers
// ---------------------------------------------------------------------------

function getFileIcon(type: ArtifactFile['type']) {
  switch (type) {
    case 'markdown': return FileText;
    case 'code': return FileCode2;
    case 'table': return Table2;
    case 'image': return ImageIcon;
    default: return File;
  }
}

function getTypeLabel(type: ArtifactFile['type']): string {
  switch (type) {
    case 'markdown': return 'MD';
    case 'code': return 'CODE';
    case 'table': return 'TABLE';
    case 'image': return 'IMG';
    default: return 'TXT';
  }
}

function getTypeColor(type: ArtifactFile['type']): string {
  switch (type) {
    case 'markdown': return 'bg-blue-100 text-blue-700 dark:bg-blue-900/30 dark:text-blue-300';
    case 'code': return 'bg-green-100 text-green-700 dark:bg-green-900/30 dark:text-green-300';
    case 'table': return 'bg-purple-100 text-purple-700 dark:bg-purple-900/30 dark:text-purple-300';
    case 'image': return 'bg-yellow-100 text-yellow-700 dark:bg-yellow-900/30 dark:text-yellow-300';
    default: return 'bg-gray-100 text-gray-700 dark:bg-gray-700 dark:text-gray-300';
  }
}

// ---------------------------------------------------------------------------
// ArtifactPanel
// ---------------------------------------------------------------------------

export function ArtifactPanel({
  artifacts,
  selectedId,
  onSelect,
  onClose: _onClose,
  className = '',
}: ArtifactPanelProps) {
  const [viewMode, setViewMode] = useState<'preview' | 'code'>('preview');
  const selected = useMemo(
    () => artifacts.find((a) => a.id === selectedId),
    [artifacts, selectedId]
  );

  // List view when no artifact is selected
  if (!selected) {
    return (
      <div className={`h-full flex flex-col ${className}`}>
        <div className="p-4 flex-1 overflow-y-auto custom-scrollbar">
          {artifacts.length === 0 ? (
            <div className="flex flex-col items-center justify-center h-full text-gray-400 dark:text-gray-500">
              <FileText className="w-8 h-8 mb-2 opacity-50" />
              <p className="text-sm">暂无产物文件</p>
              <p className="text-xs mt-1">Agent 生成文件后将在此显示</p>
            </div>
          ) : (
            <div className="space-y-2">
              {artifacts.map((artifact) => {
                const Icon = getFileIcon(artifact.type);
                return (
                  <button
                    key={artifact.id}
                    onClick={() => onSelect(artifact.id)}
                    className="w-full flex items-center gap-3 p-3 rounded-lg border border-gray-200 dark:border-gray-700 bg-white dark:bg-gray-800 hover:bg-gray-50 dark:hover:bg-gray-750 transition-colors text-left group"
                  >
                    <Icon className="w-5 h-5 text-gray-400 flex-shrink-0 group-hover:text-orange-500 transition-colors" />
                    <div className="flex-1 min-w-0">
                      <p className="text-sm font-medium text-gray-700 dark:text-gray-200 truncate">
                        {artifact.name}
                      </p>
                      <div className="flex items-center gap-2 mt-0.5">
                        <span className={`text-[10px] px-1.5 py-0.5 rounded font-medium ${getTypeColor(artifact.type)}`}>
                          {getTypeLabel(artifact.type)}
                        </span>
                        <span className="text-[11px] text-gray-400 dark:text-gray-500">
                          {new Date(artifact.createdAt).toLocaleTimeString()}
                        </span>
                      </div>
                    </div>
                  </button>
                );
              })}
            </div>
          )}
        </div>
      </div>
    );
  }

  // Detail view
  const Icon = getFileIcon(selected.type);

  return (
    <div className={`h-full flex flex-col ${className}`}>
      {/* File header */}
      <div className="px-4 py-2 border-b border-gray-200 dark:border-gray-700 flex items-center gap-2 flex-shrink-0">
        <button
          onClick={() => onSelect('')}
          className="p-1 rounded hover:bg-gray-100 dark:hover:bg-gray-700 text-gray-400 hover:text-gray-600 dark:hover:text-gray-200 transition-colors"
          title="返回文件列表"
        >
          <ChevronLeft className="w-4 h-4" />
        </button>
        <Icon className="w-4 h-4 text-orange-500 flex-shrink-0" />
        <span className="text-sm font-medium text-gray-700 dark:text-gray-200 truncate flex-1">
          {selected.name}
        </span>
        <span className={`text-[10px] px-1.5 py-0.5 rounded font-medium ${getTypeColor(selected.type)}`}>
          {getTypeLabel(selected.type)}
        </span>
      </div>

      {/* View mode toggle */}
      <div className="px-4 py-1.5 border-b border-gray-100 dark:border-gray-800 flex items-center gap-1 flex-shrink-0">
        <button
          onClick={() => setViewMode('preview')}
          className={`px-2.5 py-1 rounded text-xs font-medium transition-colors ${
            viewMode === 'preview'
              ? 'bg-orange-100 text-orange-700 dark:bg-orange-900/30 dark:text-orange-300'
              : 'text-gray-500 hover:text-gray-700 dark:hover:text-gray-300'
          }`}
        >
          预览
        </button>
        <button
          onClick={() => setViewMode('code')}
          className={`px-2.5 py-1 rounded text-xs font-medium transition-colors ${
            viewMode === 'code'
              ? 'bg-orange-100 text-orange-700 dark:bg-orange-900/30 dark:text-orange-300'
              : 'text-gray-500 hover:text-gray-700 dark:hover:text-gray-300'
          }`}
        >
          源码
        </button>
      </div>

      {/* Content area */}
      <div className="flex-1 overflow-y-auto custom-scrollbar p-4">
        {viewMode === 'preview' ? (
          <div className="prose prose-sm dark:prose-invert max-w-none">
            {selected.type === 'markdown' ? (
              <MarkdownPreview content={selected.content} />
            ) : selected.type === 'code' ? (
              <pre className="bg-gray-50 dark:bg-gray-800 rounded-lg p-3 text-xs font-mono overflow-x-auto text-gray-700 dark:text-gray-200">
                {selected.content}
              </pre>
            ) : (
              <pre className="whitespace-pre-wrap text-sm text-gray-700 dark:text-gray-200">
                {selected.content}
              </pre>
            )}
          </div>
        ) : (
          <pre className="bg-gray-50 dark:bg-gray-800 rounded-lg p-3 text-xs font-mono overflow-x-auto text-gray-700 dark:text-gray-200 leading-relaxed">
            {selected.content}
          </pre>
        )}
      </div>

      {/* Action bar */}
      <div className="px-4 py-2 border-t border-gray-200 dark:border-gray-700 flex items-center gap-2 flex-shrink-0">
        <ActionButton
          icon={<Copy className="w-3.5 h-3.5" />}
          label="复制"
          onClick={() => navigator.clipboard.writeText(selected.content)}
        />
        <ActionButton
          icon={<Download className="w-3.5 h-3.5" />}
          label="下载"
          onClick={() => downloadArtifact(selected)}
        />
      </div>
    </div>
  );
}

// ---------------------------------------------------------------------------
// ActionButton
// ---------------------------------------------------------------------------

function ActionButton({ icon, label, onClick }: { icon: React.ReactNode; label: string; onClick: () => void }) {
  const [copied, setCopied] = useState(false);

  const handleClick = () => {
    onClick();
    if (label === '复制') {
      setCopied(true);
      setTimeout(() => setCopied(false), 1500);
    }
  };

  return (
    <button
      onClick={handleClick}
      className="flex items-center gap-1.5 px-2.5 py-1.5 rounded-md text-xs font-medium text-gray-500 dark:text-gray-400 hover:text-gray-700 dark:hover:text-gray-200 hover:bg-gray-100 dark:hover:bg-gray-800 transition-colors"
    >
      {copied ? <span className="text-green-500 text-xs">已复制</span> : icon}
      {!copied && label}
    </button>
  );
}

// ---------------------------------------------------------------------------
// Simple Markdown preview (no external deps)
// ---------------------------------------------------------------------------

function MarkdownPreview({ content }: { content: string }) {
  // Basic markdown rendering: headings, bold, code blocks, lists
  const lines = content.split('\n');

  return (
    <div className="space-y-2">
      {lines.map((line, i) => {
        // Heading
        if (line.startsWith('### ')) {
          return <h3 key={i} className="text-sm font-bold text-gray-800 dark:text-gray-100 mt-3">{line.slice(4)}</h3>;
        }
        if (line.startsWith('## ')) {
          return <h2 key={i} className="text-base font-bold text-gray-800 dark:text-gray-100 mt-4">{line.slice(3)}</h2>;
        }
        if (line.startsWith('# ')) {
          return <h1 key={i} className="text-lg font-bold text-gray-800 dark:text-gray-100">{line.slice(2)}</h1>;
        }
        // Code block (simplified)
        if (line.startsWith('```')) return null;
        // List item
        if (line.startsWith('- ') || line.startsWith('* ')) {
          return <li key={i} className="text-sm text-gray-700 dark:text-gray-300 ml-4">{renderInline(line.slice(2))}</li>;
        }
        // Empty line
        if (!line.trim()) return <div key={i} className="h-2" />;
        // Regular paragraph
        return <p key={i} className="text-sm text-gray-700 dark:text-gray-300 leading-relaxed">{renderInline(line)}</p>;
      })}
    </div>
  );
}

function renderInline(text: string): React.ReactNode {
  // Bold
  const parts = text.split(/\*\*(.*?)\*\*/g);
  return parts.map((part, i) =>
    i % 2 === 1 ? <strong key={i} className="font-semibold">{part}</strong> : part
  );
}

// ---------------------------------------------------------------------------
// Download helper
// ---------------------------------------------------------------------------

function downloadArtifact(artifact: ArtifactFile) {
  const blob = new Blob([artifact.content], { type: 'text/plain;charset=utf-8' });
  const url = URL.createObjectURL(blob);
  const a = document.createElement('a');
  a.href = url;
  a.download = artifact.name;
  document.body.appendChild(a);
  a.click();
  document.body.removeChild(a);
  URL.revokeObjectURL(url);
}