import { NextRequest, NextResponse } from 'next/server'
import bcrypt from 'bcryptjs'
import { v4 as uuidv4 } from 'uuid'
import { UserService } from '@/lib/services/database-service'

const userService = new UserService()

export async function POST(request: NextRequest) {
  try {
    const { name, email, password, department, role = 'user' } = await request.json()

    if (!name || !email || !password || !department) {
      return NextResponse.json(
        { error: '請填寫所有必填欄位' },
        { status: 400 }
      )
    }

    if (password.length < 6) {
      return NextResponse.json(
        { error: '密碼長度至少需要 6 個字符' },
        { status: 400 }
      )
    }

    // 加密密碼
    const saltRounds = 12
    const password_hash = await bcrypt.hash(password, saltRounds)

    // 檢查是否為邀請用戶（狀態為 invited）
    const invitedUser = await userService.findInvitedUserByEmail(email)
    
    if (invitedUser) {
      // 更新邀請用戶為正式用戶
      const updatedUser = await userService.completeInvitedUserRegistration(
        invitedUser.id,
        name,
        department,
        password_hash,
        role
      )
      
      if (updatedUser.success) {
        const { password_hash: _, ...userWithoutPassword } = updatedUser.user
        return NextResponse.json({
          success: true,
          user: userWithoutPassword
        })
      } else {
        return NextResponse.json(
          { error: updatedUser.error || '完成註冊失敗' },
          { status: 400 }
        )
      }
    } else {
      // 檢查用戶是否已存在（活躍用戶）
      const existingUser = await userService.findByEmail(email)
      if (existingUser) {
        return NextResponse.json(
          { error: '該電子郵件已被註冊' },
          { status: 409 }
        )
      }

      // 創建新用戶
      const newUser = {
        id: uuidv4(),
        name,
        email,
        password_hash,
        department,
        role: role as 'user' | 'developer' | 'admin',
        join_date: new Date().toISOString().split('T')[0],
        total_likes: 0,
        total_views: 0,
        status: 'active' as 'active' | 'inactive' | 'invited'
      }

      const createdUser = await userService.create(newUser)

      // 返回用戶信息（不包含密碼）
      const { password_hash: _, ...userWithoutPassword } = createdUser
      return NextResponse.json({
        success: true,
        user: userWithoutPassword
      })
    }

  } catch (error) {
    console.error('註冊錯誤:', error)
    return NextResponse.json(
      { error: '註冊過程中發生錯誤' },
      { status: 500 }
    )
  }
}