import { NextRequest, NextResponse } from 'next/server';
import { getServerSession } from 'next-auth';
import { authOptions } from '@/lib/auth';
import { prisma } from '@/lib/prisma';
import { isSystemAdmin } from '@/lib/department-permission';

// GET - 获取所有平台分类
export async function GET(request: NextRequest) {
  try {
    const session = await getServerSession(authOptions);
    if (!session?.user) {
      return NextResponse.json({ error: '未登录' }, { status: 401 });
    }

    const platforms = await prisma.platform.findMany({
      orderBy: { createdAt: 'asc' },
    });

    // 统计每个平台的素材数量（只统计未删除的素材）
    const platformsWithCount = await Promise.all(
      platforms.map(async (platform) => {
        let count: number;
        try {
          count = await prisma.material.count({
            where: { 
              platformName: platform.name,
              deletedAt: null,
            } as any,
          });
        } catch (e: any) {
          // 兼容旧版本数据库（没有deletedAt字段）
          if (e?.meta?.column?.includes('deletedAt')) {
            count = await prisma.material.count({
          where: { platformName: platform.name },
        });
          } else {
            throw e;
          }
        }

        return {
          id: platform.id,
          name: platform.name,
          count,
        };
      })
    );

    return NextResponse.json(platformsWithCount);
  } catch (error) {
    console.error('Error fetching platforms:', error);
    return NextResponse.json(
      { error: '获取平台分类失败' },
      { status: 500 }
    );
  }
}

// POST - 创建新的平台分类
export async function POST(request: NextRequest) {
  try {
    const session = await getServerSession(authOptions);

    if (!session?.user || !(session.user as any).id) {
      return NextResponse.json(
        { error: '未登录' },
        { status: 401 }
      );
    }
    const userRole = (session.user as any).role;
    if (!isSystemAdmin(userRole)) {
      return NextResponse.json(
        { error: '需要管理员权限' },
        { status: 403 }
      );
    }

    const { name } = await request.json();

    if (!name || !name.trim()) {
      return NextResponse.json(
        { error: '平台分类名称不能为空' },
        { status: 400 }
      );
    }

    // 检查是否已存在
    const existing = await prisma.platform.findUnique({
      where: { name: name.trim() },
    });

    if (existing) {
      return NextResponse.json(
        { error: '该平台分类已存在' },
        { status: 400 }
      );
    }

    const platform = await prisma.platform.create({
      data: { name: name.trim() },
    });

    return NextResponse.json(platform, { status: 201 });
  } catch (error) {
    console.error('Error creating platform:', error);
    return NextResponse.json(
      { error: '创建平台分类失败' },
      { status: 500 }
    );
  }
}

// PUT - 更新平台分类
export async function PUT(request: NextRequest) {
  try {
    const session = await getServerSession(authOptions);

    if (!session?.user || !(session.user as any).id) {
      return NextResponse.json(
        { error: '未登录' },
        { status: 401 }
      );
    }
    const userRole = (session.user as any).role;
    if (!isSystemAdmin(userRole)) {
      return NextResponse.json(
        { error: '需要管理员权限' },
        { status: 403 }
      );
    }

    const { id, name } = await request.json();

    if (!id || !name || !name.trim()) {
      return NextResponse.json(
        { error: '平台分类ID和名称不能为空' },
        { status: 400 }
      );
    }

    // 检查新名称是否已被其他分类使用
    const existing = await prisma.platform.findFirst({
      where: {
        name: name.trim(),
        NOT: { id },
      },
    });

    if (existing) {
      return NextResponse.json(
        { error: '该平台分类名称已被使用' },
        { status: 400 }
      );
    }

    // 获取旧名称
    const oldPlatform = await prisma.platform.findUnique({
      where: { id },
    });

    if (!oldPlatform) {
      return NextResponse.json(
        { error: '平台分类不存在' },
        { status: 404 }
      );
    }

    // 更新分类
    const updated = await prisma.platform.update({
      where: { id },
      data: { name: name.trim() },
    });

    // 更新所有使用该分类的素材
    await prisma.material.updateMany({
      where: { platformName: oldPlatform.name },
      data: { platformName: name.trim() },
    });

    return NextResponse.json(updated);
  } catch (error) {
    console.error('Error updating platform:', error);
    return NextResponse.json(
      { error: '更新平台分类失败' },
      { status: 500 }
    );
  }
}

// DELETE - 删除平台分类
export async function DELETE(request: NextRequest) {
  try {
    const session = await getServerSession(authOptions);

    if (!session?.user || !(session.user as any).id) {
      return NextResponse.json(
        { error: '未登录' },
        { status: 401 }
      );
    }
    const userRole = (session.user as any).role;
    if (!isSystemAdmin(userRole)) {
      return NextResponse.json(
        { error: '需要管理员权限' },
        { status: 403 }
      );
    }

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

    if (!id) {
      return NextResponse.json(
        { error: '平台分类ID不能为空' },
        { status: 400 }
      );
    }

    // 检查是否有素材使用该分类
    const platform = await prisma.platform.findUnique({
      where: { id },
    });

    if (!platform) {
      return NextResponse.json(
        { error: '平台分类不存在' },
        { status: 404 }
      );
    }

    const materialCount = await prisma.material.count({
      where: { platformName: platform.name },
    });

    if (materialCount > 0) {
      return NextResponse.json(
        { error: `无法删除：有 ${materialCount} 个素材正在使用该平台分类` },
        { status: 400 }
      );
    }

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

    return NextResponse.json({ message: '平台分类已删除' });
  } catch (error) {
    console.error('Error deleting platform:', error);
    return NextResponse.json(
      { error: '删除平台分类失败' },
      { status: 500 }
    );
  }
}