import { NextRequest, NextResponse } from "next/server";
import { db, recipes, users, favorites, eq, desc, sql, and, gte } from "@epicure/db";

export async function GET(req: NextRequest) {
  const { searchParams } = new URL(req.url);
  const limitRaw = parseInt(searchParams.get("limit") ?? "20");
  const limit = Math.min(Number.isNaN(limitRaw) ? 20 : Math.max(1, limitRaw), 50);
  const offsetRaw = parseInt(searchParams.get("offset") ?? "0");
  const offset = Number.isNaN(offsetRaw) ? 0 : Math.max(0, offsetRaw);

  const sevenDaysAgo = new Date(Date.now() - 7 * 24 * 60 * 60 * 1000);

  const [trending, totalRow] = await Promise.all([
    db
      .select({
        id: recipes.id,
        title: recipes.title,
        description: recipes.description,
        baseServings: recipes.baseServings,
        prepMins: recipes.prepMins,
        cookMins: recipes.cookMins,
        difficulty: recipes.difficulty,
        visibility: recipes.visibility,
        aiGenerated: recipes.aiGenerated,
        createdAt: recipes.createdAt,
        authorId: recipes.authorId,
        authorName: users.name,
        authorUsername: users.username,
        authorAvatarUrl: users.avatarUrl,
        favoriteCount: sql<number>`cast(count(${favorites.recipeId}) as int)`,
      })
      .from(recipes)
      .innerJoin(users, eq(recipes.authorId, users.id))
      .leftJoin(
        favorites,
        and(eq(favorites.recipeId, recipes.id), gte(favorites.createdAt, sevenDaysAgo))
      )
      .where(eq(recipes.visibility, "public"))
      .groupBy(recipes.id, users.id)
      .orderBy(desc(sql`count(${favorites.recipeId})`), desc(recipes.createdAt))
      .limit(limit)
      .offset(offset),
    db
      .select({ total: sql<number>`count(*)::int` })
      .from(recipes)
      .where(eq(recipes.visibility, "public")),
  ]);

  const total = totalRow[0]?.total ?? 0;

  return NextResponse.json({
    data: trending.map((r) => ({ ...r, createdAt: r.createdAt.toISOString() })),
    total,
    limit,
    offset,
  });
}