'use client';

import { useState, useEffect, useTransition } from 'react';
import { useRouter, useParams } from 'next/navigation';
import { Button } from '@/components/ui/button';
import { Label } from '@/components/ui/label';
import { Textarea } from '@/components/ui/textarea';
import { Save, Eye } from 'lucide-react';
import { toast } from 'sonner';
import Link from 'next/link';
import { getTemplateAction, updateTemplateAction, previewTemplateAction, TemplateFile } from '@/lib/mail/service';

type Template = TemplateFile;

interface MailTemplateEditorClientProps {
  templateName: string;
  initialTemplate?: Template | null;
}

export default function MailTemplateEditorClient({ 
  templateName, 
  initialTemplate 
}: MailTemplateEditorClientProps) {
  const router = useRouter();
  const params = useParams();
  
  const lng = (params?.lng as string) || 'ko';

  const [template, setTemplate] = useState<Template | null>(initialTemplate || null);
  const [content, setContent] = useState(initialTemplate?.content || '');
  const [loading, setLoading] = useState(!initialTemplate);
  const [saving, setSaving] = useState(false);
  const [previewLoading, setPreviewLoading] = useState(false);
  const [previewHtml, setPreviewHtml] = useState<string | null>(null);
  const [, startTransition] = useTransition();

  // 템플릿 조회
  const fetchTemplate = async () => {
    if (!templateName) {
      toast.error('잘못된 접근입니다.');
      router.push(`/${lng}/evcp/email-template`);
      return;
    }

    try {
      setLoading(true);
      startTransition(async () => {
        const result = await getTemplateAction(templateName);

        if (result.success && result.data) {
          setTemplate(result.data);
          setContent(result.data.content);
        } else {
          toast.error(result.error || '템플릿을 찾을 수 없습니다.');
          router.push(`/${lng}/evcp/email-template`);
        }
        setLoading(false);
      });
    } catch (error) {
      console.error('Error fetching template:', error);
      toast.error('템플릿을 불러오는데 실패했습니다.');
      router.push(`/${lng}/evcp/email-template`);
      setLoading(false);
    }
  };

  // 템플릿 저장
  const handleSave = async () => {
    if (!content.trim()) {
      toast.error('템플릿 내용을 입력해주세요.');
      return;
    }

    try {
      setSaving(true);
      startTransition(async () => {
        const result = await updateTemplateAction(templateName, content);

        if (result.success && result.data) {
          toast.success('템플릿이 성공적으로 저장되었습니다.');
          setTemplate(result.data);
        } else {
          toast.error(result.error || '템플릿 저장에 실패했습니다.');
        }
        setSaving(false);
      });
    } catch (error) {
      console.error('Error saving template:', error);
      toast.error('템플릿 저장에 실패했습니다.');
      setSaving(false);
    }
  };

  // 미리보기 생성
  const handlePreview = async () => {
    try {
      setPreviewLoading(true);
      startTransition(async () => {
        const result = await previewTemplateAction(
          templateName,
          {
            userName: '홍길동',
            companyName: 'EVCP',
            email: 'user@example.com',
            date: new Date().toLocaleDateString('ko-KR'),
            projectName: '샘플 프로젝트',
            message: '이것은 샘플 메시지입니다.',
            currentYear: new Date().getFullYear(),
            language: 'ko',
            name: '홍길동',
            loginUrl: 'https://example.com/login'
          }
        );

        if (result.success && result.data) {
          setPreviewHtml(result.data.html);
        } else {
          toast.error(result.error || '미리보기 생성에 실패했습니다.');
        }
        setPreviewLoading(false);
      });
    } catch (error) {
      console.error('Error generating preview:', error);
      toast.error('미리보기 생성에 실패했습니다.');
      setPreviewLoading(false);
    }
  };

  useEffect(() => {
    if (!initialTemplate) {
      fetchTemplate();
    }
  }, [templateName, initialTemplate]);

  if (loading) {
    return (
      <div className="text-center py-20">
        <div className="animate-spin rounded-full h-12 w-12 border-b-2 border-blue-600 mx-auto"></div>
        <p className="mt-4 text-gray-600">템플릿을 불러오는 중...</p>
      </div>
    );
  }

  if (!template) {
    return (
      <div className="text-center py-20">
        <p className="text-gray-600">템플릿을 찾을 수 없습니다.</p>
        <Link href={`/${lng}/evcp/email-template`}>
          <Button className="mt-4">목록으로 돌아가기</Button>
        </Link>
      </div>
    );
  }

  return (
    <div className="space-y-8">
      {/* 헤더 */}
      <div>
        <div className="flex items-center gap-4 mb-4">
          <h1 className="text-3xl font-bold text-gray-900">템플릿 편집</h1>
        </div>
        <div>
          <p className="text-gray-600">
            <span className="font-medium">{template.name}</span> 템플릿을 편집합니다.
          </p>
          <p className="text-sm text-gray-500">
            마지막 수정: {new Date(template.lastModified).toLocaleString('ko-KR')}
          </p>
        </div>
      </div>

      <div className="grid grid-cols-1 lg:grid-cols-2 gap-8">
        {/* 편집 영역 */}
        <div className="space-y-6">
          <div className="bg-white p-6 rounded-lg shadow">
            <h2 className="text-xl font-semibold mb-4">템플릿 내용</h2>
            
            <div className="space-y-4">
              <div>
                <Label htmlFor="content">Handlebars 템플릿</Label>
                <Textarea
                  id="content"
                  value={content}
                  onChange={(e) => setContent(e.target.value)}
                  className="min-h-[500px] font-mono text-sm"
                />
              </div>

              <div className="flex gap-2">
                <Button onClick={handleSave} disabled={saving}>
                  <Save className="h-4 w-4 mr-2" />
                  {saving ? '저장 중...' : '저장'}
                </Button>
                <Button variant="outline" onClick={handlePreview} disabled={previewLoading}>
                  <Eye className="h-4 w-4 mr-2" />
                  {previewLoading ? '생성 중...' : '미리보기'}
                </Button>
              </div>
            </div>
          </div>
        </div>

        {/* 미리보기 영역 */}
        <div className="space-y-6">
          <div className="bg-white p-6 rounded-lg shadow">
            <h2 className="text-xl font-semibold mb-4">빠른 미리보기</h2>
            
            <div className="border rounded-lg p-4 min-h-[500px] bg-gray-50 overflow-auto">
              {previewHtml ? (
                <div 
                  className="preview-content"
                  dangerouslySetInnerHTML={{ __html: previewHtml }}
                />
              ) : (
                <div className="text-center text-gray-500 py-20">
                  미리보기 버튼을 클릭하여 결과를 확인하세요.
                </div>
              )}
            </div>
          </div>

          {/* 도움말 */}
          <div className="bg-blue-50 p-4 rounded-lg">
            <h3 className="font-semibold text-blue-900 mb-2">Handlebars 문법 도움말</h3>
            <div className="text-sm text-blue-800 space-y-1">
              <p><code>{`{{variable}}`}</code> - 변수 출력</p>
              <p><code>{`{{{html}}}`}</code> - HTML 출력 (이스케이프 없음)</p>
              <p><code>{`{{#if condition}}`}</code> - 조건문</p>
              <p><code>{`{{#each items}}`}</code> - 반복문</p>
            </div>
          </div>

          {/* 샘플 데이터 */}
          <div className="bg-gray-50 p-4 rounded-lg">
            <h3 className="font-semibold text-gray-900 mb-2">미리보기 샘플 데이터</h3>
            <pre className="text-xs text-gray-600 overflow-auto">
{JSON.stringify({
  userName: '홍길동',
  companyName: 'EVCP',
  email: 'user@example.com',
  date: new Date().toLocaleDateString('ko-KR'),
  projectName: '샘플 프로젝트',
  message: '이것은 샘플 메시지입니다.',
  currentYear: new Date().getFullYear(),
  language: 'ko',
  name: '홍길동',
  loginUrl: 'https://example.com/login'
}, null, 2)}
            </pre>
          </div>
        </div>
      </div>
    </div>
  );
}