import { NextRequest, NextResponse } from 'next/server'
import { prisma } from '@/lib/prisma'
import { auth } from '@/lib/auth'
import { hashPassword } from 'better-auth/crypto'
import { v4 as uuidv4 } from 'uuid'

// GET /api/users - Get all users
export async function GET(request: NextRequest) {
  try {
    const session = await auth.api.getSession({
      headers: request.headers,
    })

    if (!session) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
    }

    const users = await prisma.user.findMany({
      orderBy: { createdAt: 'desc' },
      select: {
        id: true,
        email: true,
        emailVerified: true,
        name: true,
        image: true,
        createdAt: true,
        updatedAt: true,
      },
    })

    return NextResponse.json(users)
  } catch (error) {
    console.error('Error fetching users:', error)
    return NextResponse.json(
      { error: 'Failed to fetch users' },
      { status: 500 }
    )
  }
}

// POST /api/users - Create a new user
export async function POST(request: NextRequest) {
  try {
    const session = await auth.api.getSession({
      headers: request.headers,
    })

    if (!session) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
    }

    const body = await request.json()
    const { email, password, name } = body

    if (!email || !password) {
      return NextResponse.json(
        { error: 'email and password are required' },
        { status: 400 }
      )
    }

    // Check if user already exists
    const existingUser = await prisma.user.findUnique({
      where: { email },
    })

    if (existingUser) {
      return NextResponse.json(
        { error: '该邮箱已被注册' },
        { status: 400 }
      )
    }

    // Hash password
    const hashedPassword = await hashPassword(password)

    const userId = uuidv4()
    const accountId = uuidv4()

    // Create user and account in transaction
    const user = await prisma.$transaction(async (tx) => {
      const newUser = await tx.user.create({
        data: {
          id: userId,
          email,
          name: name || null,
        },
      })

      await tx.account.create({
        data: {
          id: accountId,
          accountId: userId,
          providerId: 'credential',
          userId: userId,
          password: hashedPassword,
        },
      })

      return newUser
    })

    return NextResponse.json(user, { status: 201 })
  } catch (error) {
    console.error('Error creating user:', error)
    return NextResponse.json(
      { error: 'Failed to create user' },
      { status: 500 }
    )
  }
}

// PUT /api/users - Update a user
export async function PUT(request: NextRequest) {
  try {
    const session = await auth.api.getSession({
      headers: request.headers,
    })

    if (!session) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
    }

    const body = await request.json()
    const { id, email, password, name } = body

    if (!id) {
      return NextResponse.json({ error: 'id is required' }, { status: 400 })
    }

    // Check if email is taken by another user
    if (email) {
      const existingUser = await prisma.user.findFirst({
        where: {
          email,
          NOT: { id },
        },
      })

      if (existingUser) {
        return NextResponse.json(
          { error: '该邮箱已被其他用户使用' },
          { status: 400 }
        )
      }
    }

    // Update user and optionally password
    const user = await prisma.$transaction(async (tx) => {
      const updatedUser = await tx.user.update({
        where: { id },
        data: {
          email,
          name: name || null,
        },
      })

      if (password) {
        const hashedPassword = await hashPassword(password)
        await tx.account.updateMany({
          where: { userId: id, providerId: 'credential' },
          data: { password: hashedPassword },
        })
      }

      return updatedUser
    })

    return NextResponse.json(user)
  } catch (error) {
    console.error('Error updating user:', error)
    return NextResponse.json(
      { error: 'Failed to update user' },
      { status: 500 }
    )
  }
}

// DELETE /api/users - Delete a user
export async function DELETE(request: NextRequest) {
  try {
    const session = await auth.api.getSession({
      headers: request.headers,
    })

    if (!session) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
    }

    const { searchParams } = new URL(request.url)
    const id = searchParams.get('id')

    if (!id) {
      return NextResponse.json({ error: 'id is required' }, { status: 400 })
    }

    // Prevent deleting yourself
    if (id === session.user.id) {
      return NextResponse.json(
        { error: '不能删除自己的账户' },
        { status: 400 }
      )
    }

    await prisma.user.delete({
      where: { id },
    })

    return NextResponse.json({ success: true })
  } catch (error) {
    console.error('Error deleting user:', error)
    return NextResponse.json(
      { error: 'Failed to delete user' },
      { status: 500 }
    )
  }
}