import { NextRequest, NextResponse } from 'next/server';
import { CriteriaTemplateService, CriteriaItemService } from '@/lib/services/database';

// GET - 獲取所有評分標準模板
export async function GET() {
  try {
    // 這裡暫時使用 user_id = 1，實際應用中應該從 session 獲取
    const templates = await CriteriaTemplateService.findByUserId(1);
    
    // 獲取每個模板的評分項目
    const templatesWithItems = await Promise.all(
      templates.map(async (template) => {
        const items = await CriteriaItemService.findByTemplateId(template.id);
        return { ...template, items };
      })
    );

    return NextResponse.json({
      success: true,
      data: templatesWithItems
    });
  } catch (error) {
    console.error('獲取評分標準模板失敗:', error);
    return NextResponse.json(
      { success: false, error: '獲取評分標準模板失敗' },
      { status: 500 }
    );
  }
}

// POST - 創建或更新評分標準模板（單一模板模式）
export async function POST(request: NextRequest) {
  try {
    const body = await request.json();
    const { name, description, items } = body;

    if (!name || !items || !Array.isArray(items)) {
      return NextResponse.json(
        { success: false, error: '請提供模板名稱和評分項目' },
        { status: 400 }
      );
    }

    // 驗證權重總和
    const totalWeight = items.reduce((sum: number, item: any) => sum + (Number(item.weight) || 0), 0);
    if (Math.abs(totalWeight - 100) > 0.01) {
      return NextResponse.json(
        { success: false, error: '權重總和必須等於 100%' },
        { status: 400 }
      );
    }

    // 驗證所有項目都有名稱
    if (items.some((item: any) => !item.name?.trim())) {
      return NextResponse.json(
        { success: false, error: '所有評分項目都必須有名稱' },
        { status: 400 }
      );
    }

    // 使用事務創建或更新模板
    const { transaction } = await import('@/lib/database');
    
    const result = await transaction(async (connection) => {
      // 檢查是否已存在模板
      const [existingTemplates] = await connection.execute(
        'SELECT id FROM criteria_templates WHERE user_id = ? LIMIT 1',
        [1]
      );
      
      let templateId;
      
      if (existingTemplates.length > 0) {
        // 更新現有模板
        templateId = existingTemplates[0].id;
        await connection.execute(
          'UPDATE criteria_templates SET name = ?, description = ?, total_weight = ?, updated_at = NOW() WHERE id = ?',
          [name, description || '', totalWeight, templateId]
        );
        
        // 刪除舊的評分項目
        await connection.execute(
          'DELETE FROM criteria_items WHERE template_id = ?',
          [templateId]
        );
      } else {
        // 創建新模板
        const [templateResult] = await connection.execute(
          'INSERT INTO criteria_templates (user_id, name, description, is_default, is_public, total_weight) VALUES (?, ?, ?, ?, ?, ?)',
          [1, name, description || '', 1, 1, totalWeight]
        );
        templateId = (templateResult as any).insertId;
      }
      
      // 創建評分項目
      for (let i = 0; i < items.length; i++) {
        const item = items[i];
        await connection.execute(
          'INSERT INTO criteria_items (template_id, name, description, weight, max_score, sort_order) VALUES (?, ?, ?, ?, ?, ?)',
          [
            templateId,
            item.name,
            item.description || '',
            Number(item.weight) || 0,
            Number(item.maxScore) || 10,
            i + 1
          ]
        );
      }
      
      return templateId;
    });

    return NextResponse.json({
      success: true,
      data: { id: result },
      message: '評分標準模板儲存成功'
    });
  } catch (error) {
    console.error('儲存評分標準模板失敗:', error);
    return NextResponse.json(
      { success: false, error: '儲存評分標準模板失敗' },
      { status: 500 }
    );
  }
}