/**
 * Component: Admin Requests API (Paginated)
 * Documentation: documentation/admin-dashboard.md
 */

import { NextRequest, NextResponse } from 'next/server';
import { requireAuth, requireAdmin, AuthenticatedRequest } from '@/lib/middleware/auth';
import { prisma } from '@/lib/db';
import { RMABLogger } from '@/lib/utils/logger';
import { Prisma } from '@/generated/prisma';

const logger = RMABLogger.create('API.Admin.Requests');

const VALID_SORT_FIELDS = ['createdAt', 'completedAt', 'title', 'user', 'status'] as const;
const VALID_SORT_ORDERS = ['asc', 'desc'] as const;
const VALID_PAGE_SIZES = [10, 25, 50, 100] as const;

type SortField = (typeof VALID_SORT_FIELDS)[number];
type SortOrder = (typeof VALID_SORT_ORDERS)[number];

export async function GET(request: NextRequest) {
  return requireAuth(request, async (req: AuthenticatedRequest) => {
    return requireAdmin(req, async () => {
      try {
        const { searchParams } = new URL(request.url);

        // Parse query parameters
        const page = Math.max(1, parseInt(searchParams.get('page') || '1', 10));
        const pageSizeParam = parseInt(searchParams.get('pageSize') || '25', 10);
        const pageSize = VALID_PAGE_SIZES.includes(pageSizeParam as (typeof VALID_PAGE_SIZES)[number])
          ? pageSizeParam
          : 25;
        const search = searchParams.get('search')?.trim() || '';
        const status = searchParams.get('status') || '';
        const userId = searchParams.get('userId') || '';
        const sortByParam = searchParams.get('sortBy') || 'createdAt';
        const sortBy: SortField = VALID_SORT_FIELDS.includes(sortByParam as SortField)
          ? (sortByParam as SortField)
          : 'createdAt';
        const sortOrderParam = searchParams.get('sortOrder') || 'desc';
        const sortOrder: SortOrder = VALID_SORT_ORDERS.includes(sortOrderParam as SortOrder)
          ? (sortOrderParam as SortOrder)
          : 'desc';

        // Build where clause
        const where: Prisma.RequestWhereInput = {
          deletedAt: null,
        };

        // Filter by status
        if (status && status !== 'all') {
          where.status = status;
        }

        // Filter by user
        if (userId) {
          where.userId = userId;
        }

        // Search by title or author
        if (search) {
          where.audiobook = {
            OR: [
              { title: { contains: search, mode: 'insensitive' } },
              { author: { contains: search, mode: 'insensitive' } },
            ],
          };
        }

        // Build orderBy clause
        let orderBy: Prisma.RequestOrderByWithRelationInput;
        switch (sortBy) {
          case 'title':
            orderBy = { audiobook: { title: sortOrder } };
            break;
          case 'user':
            orderBy = { user: { plexUsername: sortOrder } };
            break;
          case 'completedAt':
            // Sort nulls last for completedAt
            orderBy = { completedAt: { sort: sortOrder, nulls: 'last' } };
            break;
          case 'status':
            orderBy = { status: sortOrder };
            break;
          case 'createdAt':
          default:
            orderBy = { createdAt: sortOrder };
            break;
        }

        // Get total count for pagination
        const total = await prisma.request.count({ where });

        // Get paginated requests
        const requests = await prisma.request.findMany({
          where,
          include: {
            audiobook: {
              select: {
                id: true,
                title: true,
                author: true,
                audibleAsin: true,
              },
            },
            user: {
              select: {
                id: true,
                plexUsername: true,
              },
            },
            downloadHistory: {
              where: {
                selected: true,
              },
              select: {
                torrentUrl: true,
              },
              take: 1,
            },
          },
          orderBy,
          skip: (page - 1) * pageSize,
          take: pageSize,
        });

        // Format response
        const formatted = requests.map((request) => ({
          requestId: request.id,
          title: request.audiobook.title,
          author: request.audiobook.author,
          asin: request.audiobook.audibleAsin || null,
          status: request.status,
          type: request.type || 'audiobook', // Include request type for UI display
          userId: request.user.id,
          user: request.user.plexUsername,
          createdAt: request.createdAt,
          completedAt: request.completedAt,
          errorMessage: request.errorMessage,
          torrentUrl: request.downloadHistory[0]?.torrentUrl || null,
        }));

        return NextResponse.json({
          requests: formatted,
          total,
          page,
          pageSize,
          totalPages: Math.ceil(total / pageSize),
        });
      } catch (error) {
        logger.error('Failed to fetch requests', {
          error: error instanceof Error ? error.message : String(error),
        });
        return NextResponse.json({ error: 'Failed to fetch requests' }, { status: 500 });
      }
    });
  });
}