import { NextResponse } from 'next/server';
import { getServerSession } from 'next-auth';
import { authOptions } from '@/lib/auth';
import { prisma } from '@/lib/prisma';
import { buildMaterialPrivacyWhere } from '@/lib/task-detail-privacy';

// GET - 获取素材统计数据（只统计未删除的素材）
export async function GET() {
  try {
    const session = await getServerSession(authOptions);
    if (!session?.user) {
      return NextResponse.json({ error: '未登录' }, { status: 401 });
    }
    const privacyWhere = await buildMaterialPrivacyWhere((session.user as any).id);

    // 获取总数（只统计未删除的素材）
    let total: number;
    let materials: Array<{ createdAt: Date }>;
    
    try {
      total = await prisma.material.count({
        where: {
          deletedAt: null,
          AND: [privacyWhere],
        } as any,
      });
    
      // 获取所有未删除素材的创建时间
      materials = await prisma.material.findMany({
        where: {
          deletedAt: null,
          AND: [privacyWhere],
        } as any,
        select: {
          createdAt: true,
        },
        orderBy: {
          createdAt: 'desc',
        },
      });
    } catch (e: any) {
      // 兼容旧版本数据库（没有deletedAt字段）
      if (e?.meta?.column?.includes('deletedAt')) {
        console.warn('[Materials Stats] deletedAt field not found, using all materials');
        total = await prisma.material.count({ where: privacyWhere });
        materials = await prisma.material.findMany({
      where: privacyWhere,
      select: {
        createdAt: true,
      },
      orderBy: {
        createdAt: 'desc',
      },
    });
      } else {
        throw e;
      }
    }
    
    // 按月份统计
    const monthMap = new Map<string, number>();
    
    materials.forEach(material => {
      const date = new Date(material.createdAt);
      const monthKey = `${date.getFullYear()}-${String(date.getMonth() + 1).padStart(2, '0')}`;
      monthMap.set(monthKey, (monthMap.get(monthKey) || 0) + 1);
    });
    
    // 格式化月份数据
    const months = Array.from(monthMap.entries())
      .map(([value, count]) => {
        const [year, month] = value.split('-');
        return {
          value,
          label: `${year}年${parseInt(month)}月`,
          count,
        };
      })
      .sort((a, b) => b.value.localeCompare(a.value)); // 降序排列
    
    return NextResponse.json({
      total,
      months,
    }, { headers: { 'Cache-Control': 'private, no-store' } });
  } catch (error) {
    console.error('Error fetching material stats:', error);
    return NextResponse.json(
      { error: '获取统计数据失败' },
      { status: 500 }
    );
  }
}