import { useState } from 'react';
import md from 'markdown-it';
import ReactMarkdown from 'react-markdown';
import remarkGfm from 'remark-gfm';
import rehypeRaw from 'rehype-raw';
import { Button } from '@/components/ui/button';
import { Code, Eye } from 'lucide-react';

type MarkdownEditorProps = {
  content: string;
  onChange: (content: string) => void;
  placeholder?: string;
  greeting?: string;
  firstName?: string;
  lastName?: string;
};

export function MarkdownEditor({
  content,
  onChange,
  placeholder = 'Enter markdown...',
  greeting,
  firstName,
  lastName,
}: MarkdownEditorProps) {
  const [showPreview, setShowPreview] = useState(false);

  const markdown = md({
    html: true,
    breaks: true,
    linkify: true,
  });

  const processGreeting = (text: string) => {
    return text
      .replace(/\{\{firstName\}\}/g, firstName || '')
      .replace(/\{\{fullName\}\}/g, `${firstName || ''} ${lastName || ''}`.trim());
  };

  const processedGreeting = greeting ? processGreeting(greeting) : '';
  const greetingHtml = processedGreeting ? `<p>${processedGreeting}</p>` : '';
  const preview = markdown.render(content);

  return (
    <div className="flex flex-col rounded-lg border border-border bg-background overflow-hidden">
      {/* Toolbar */}
      <div className="flex items-center gap-2 border-b border-border bg-muted px-4 py-2">
        <Button size="sm" variant={!showPreview ? 'default' : 'outline'} onClick={() => setShowPreview(false)}>
          <Code className="h-4 w-4 mr-2" />
          Markdown
        </Button>
        <Button size="sm" variant={showPreview ? 'default' : 'outline'} onClick={() => setShowPreview(true)}>
          <Eye className="h-4 w-4 mr-2" />
          Preview
        </Button>
      </div>

      {/* Content Area */}
      <div className="flex-1 overflow-hidden">
        {!showPreview ? (
          <textarea
            rows={15}
            name="content"
            value={content}
            onChange={(e: React.ChangeEvent<HTMLTextAreaElement>) => onChange(e.target.value)}
            placeholder={placeholder}
            className="w-full h-full resize-none p-4 font-mono text-sm focus:outline-none bg-background text-foreground placeholder:text-muted-foreground overflow-auto"
          />
        ) : (
          <div className="w-full h-full overflow-auto bg-slate-50 dark:bg-slate-900 p-4">
            {/* Email wrapper simulation */}
            <div className="mx-auto max-w-2xl rounded-lg bg-background p-8 shadow-lg">
              {/* Logo */}
              <div className="mb-8 text-center">
                <img src="https://app.pertento.ai/logo.png" alt="Pertento" className="h-16 mx-auto" />
              </div>

              {/* Content */}
              <div className="space-y-4">
                {processedGreeting && <p className="text-base leading-relaxed">{processedGreeting}</p>}
                <style>{`
                   .markdown-preview h1 { font-size: 2rem; font-weight: bold; margin: 1.5rem 0 1rem 0; }
                   .markdown-preview h2 { font-size: 1.5rem; font-weight: bold; margin: 1.25rem 0 0.75rem 0; }
                   .markdown-preview h3 { font-size: 1.25rem; font-weight: bold; margin: 1rem 0 0.5rem 0; }
                   .markdown-preview p { margin: 0.75rem 0; line-height: 1.6; }
                   /* list-style is restored explicitly — tailwind preflight strips it, which leaves an
                      ordered list indented but unnumbered. */
                   .markdown-preview ul, .markdown-preview ol { margin: 1rem 0; padding-left: 2rem; list-style-position: outside; }
                   .markdown-preview ul { list-style-type: disc; }
                   .markdown-preview ol { list-style-type: decimal; }
                   .markdown-preview ul ul { list-style-type: circle; }
                   .markdown-preview ol ol { list-style-type: lower-alpha; }
                   .markdown-preview li { margin: 0.5rem 0; line-height: 1.6; }
                   .markdown-preview code { background-color: rgb(229, 229, 229); color: rgb(31, 41, 55); padding: 0.25rem 0.5rem; border-radius: 0.25rem; font-size: 0.875rem; }
                   .markdown-preview pre { background-color: rgb(17, 24, 39); color: rgb(243, 244, 246); padding: 1rem; border-radius: 0.5rem; overflow-x: auto; margin: 1rem 0; }
                   .markdown-preview pre code { background-color: transparent; color: inherit; padding: 0; }
                   .markdown-preview a { color: rgb(37, 99, 235); text-decoration: underline; }
                   .markdown-preview blockquote { border-left: 4px solid rgb(209, 213, 219); padding-left: 1rem; font-style: italic; margin: 1rem 0; }
                   .dark .markdown-preview code { background-color: rgb(55, 65, 81); color: rgb(243, 244, 246); }
                   .dark .markdown-preview a { color: rgb(96, 165, 250); }
                   .dark .markdown-preview blockquote { border-left-color: rgb(75, 85, 99); }
                 `}</style>
                <div className="markdown-preview">
                  <ReactMarkdown remarkPlugins={[remarkGfm]} rehypePlugins={[rehypeRaw]}>
                    {content}
                  </ReactMarkdown>
                </div>
              </div>
            </div>
          </div>
        )}
      </div>
    </div>
  );
}