import React, { useState, useMemo } from 'react';
import {
  Code,
  Eye,
  Copy,
  Check,
  ShieldCheck,
  ExternalLink,
} from 'lucide-react';
import { BrandLogo } from '../ui/BrandLogo';
import { parseMarkdownToHtml, isHtmlContent } from '../../lib/markdownUtils';

interface MarkdownViewerProps {
  content: string;
  subject?: string;
  showBrandingHeader?: boolean;
  className?: string;
}

export const MarkdownViewer: React.FC<MarkdownViewerProps> = ({
  content,
  subject,
  showBrandingHeader = true,
  className = '',
}) => {
  const [viewMode, setViewMode] = useState<'rendered' | 'raw'>('rendered');
  const [copied, setCopied] = useState(false);

  const isHtml = useMemo(() => isHtmlContent(content), [content]);

  const renderedHtml = useMemo(() => {
    if (!content) return '<p class="text-slate-400 italic">No content</p>';
    if (isHtml) return content;
    return parseMarkdownToHtml(content);
  }, [content, isHtml]);

  const handleCopy = () => {
    navigator.clipboard.writeText(content);
    setCopied(true);
    setTimeout(() => setCopied(false), 2000);
  };

  return (
    <div className={`flex flex-col rounded-2xl bg-slate-900/40 border border-slate-800/80 overflow-hidden ${className}`}>
      {/* Top Controls Bar */}
      <div className="px-4 py-2 border-b border-slate-800 bg-[#0d1322]/80 flex items-center justify-between text-xs text-slate-400">
        <div className="flex items-center gap-2">
          {showBrandingHeader && (
            <div className="flex items-center gap-1.5 text-slate-300 font-semibold pr-2 border-r border-slate-700/60">
              <BrandLogo size={18} showGlow={false} animateOnHover={false} />
              <span className="text-[11px] tracking-tight">PFM Markdown Engine</span>
            </div>
          )}
          <span className="text-[10px] text-blue-400 font-mono">
            {isHtml ? 'Format: HTML Email' : 'Format: GitHub Flavored Markdown'}
          </span>
        </div>

        <div className="flex items-center gap-2">
          {/* Toggle View Mode */}
          <div className="flex items-center rounded-lg bg-slate-950/70 p-0.5 border border-slate-800">
            <button
              type="button"
              onClick={() => setViewMode('rendered')}
              className={`flex items-center gap-1 px-2 py-1 rounded-md text-[11px] font-medium transition cursor-pointer ${
                viewMode === 'rendered'
                  ? 'bg-blue-600/30 text-white font-semibold shadow-xs'
                  : 'text-slate-400 hover:text-white'
              }`}
            >
              <Eye className="w-3 h-3" />
              <span>Rendered</span>
            </button>
            <button
              type="button"
              onClick={() => setViewMode('raw')}
              className={`flex items-center gap-1 px-2 py-1 rounded-md text-[11px] font-medium transition cursor-pointer ${
                viewMode === 'raw'
                  ? 'bg-blue-600/30 text-white font-semibold shadow-xs'
                  : 'text-slate-400 hover:text-white'
              }`}
            >
              <Code className="w-3 h-3" />
              <span>Raw Source</span>
            </button>
          </div>

          {/* Copy Button */}
          <button
            type="button"
            onClick={handleCopy}
            className="flex items-center gap-1 px-2 py-1 rounded-lg bg-slate-800 hover:bg-slate-700 text-slate-300 hover:text-white text-[11px] font-medium transition cursor-pointer border border-slate-700/60"
            title="Copy content to clipboard"
          >
            {copied ? (
              <>
                <Check className="w-3 h-3 text-emerald-400" />
                <span className="text-emerald-300">Copied</span>
              </>
            ) : (
              <>
                <Copy className="w-3 h-3" />
                <span>Copy</span>
              </>
            )}
          </button>
        </div>
      </div>

      {/* Content Rendering */}
      {viewMode === 'rendered' ? (
        <div className="p-6 overflow-x-auto text-sm leading-relaxed text-slate-200 font-sans">
          {isHtml ? (
            <div
              className="prose prose-invert max-w-none"
              dangerouslySetInnerHTML={{ __html: renderedHtml }}
            />
          ) : (
            <div
              className="prose prose-invert max-w-none [&_h1]:text-white [&_h2]:text-white [&_h3]:text-white [&_h4]:text-white [&_a]:text-blue-400 [&_a:hover]:underline [&_table]:border-collapse [&_th]:border [&_th]:border-slate-700 [&_th]:p-2 [&_td]:border [&_td]:border-slate-800 [&_td]:p-2 [&_blockquote]:border-l-4 [&_blockquote]:border-blue-500 [&_blockquote]:pl-4 [&_blockquote]:italic [&_code]:bg-slate-800 [&_code]:px-1.5 [&_code]:py-0.5 [&_code]:rounded [&_code]:text-blue-300"
              dangerouslySetInnerHTML={{ __html: renderedHtml }}
            />
          )}
        </div>
      ) : (
        <pre className="p-5 overflow-x-auto font-mono text-xs text-slate-300 bg-[#070b13] select-all whitespace-pre-wrap leading-relaxed">
          {content}
        </pre>
      )}

      {/* Branded Footer Stamp */}
      {showBrandingHeader && (
        <div className="px-5 py-2.5 border-t border-slate-800/80 bg-[#0a0f1b] flex items-center justify-between text-[11px] text-slate-400">
          <div className="flex items-center gap-1.5">
            <ShieldCheck className="w-3.5 h-3.5 text-blue-400" />
            <span>Verified PFM Secure Platform Formatting</span>
          </div>
          <span className="font-mono text-[10px] text-slate-400">
            {content.length} characters
          </span>
        </div>
      )}
    </div>
  );
};