import { db } from "@/lib/db";
import { comparisons, comparisonItems } from "@/lib/db/schema";
import { eq, and, desc, ilike, sql, inArray } from "drizzle-orm";

export async function GET(request: Request) {
  const { searchParams } = new URL(request.url);
  const page = Math.max(1, Number(searchParams.get("page")) || 1);
  const limit = Math.min(100, Math.max(1, Number(searchParams.get("limit")) || 20));
  const search = searchParams.get("search") || "";
  const offset = (page - 1) * limit;

  const conditions = [eq(comparisons.isPublic, true), eq(comparisons.status, "completed")];
  if (search) {
    conditions.push(ilike(comparisons.title, `%${search}%`));
  }

  const where = and(...conditions);

  const [result, countResult] = await Promise.all([
    db
      .select()
      .from(comparisons)
      .where(where)
      .orderBy(desc(comparisons.createdAt))
      .limit(limit)
      .offset(offset),
    db
      .select({ count: sql<number>`count(*)` })
      .from(comparisons)
      .where(where),
  ]);

  const total = countResult[0].count;

  const comparisonIds = result.map((c) => c.id);
  const itemsMap: Record<string, string[]> = {};

  if (comparisonIds.length > 0) {
    const items = await db
      .select({
        comparisonId: comparisonItems.comparisonId,
        name: comparisonItems.name,
      })
      .from(comparisonItems)
      .where(inArray(comparisonItems.comparisonId, comparisonIds));

    for (const item of items) {
      if (!itemsMap[item.comparisonId]) itemsMap[item.comparisonId] = [];
      itemsMap[item.comparisonId].push(item.name);
    }
  }

  const data = result.map((c) => ({
    id: c.id,
    title: c.title,
    summary: (c.summary || "").slice(0, 200),
    slug: c.slug,
    tags: c.tags || [],
    items: itemsMap[c.id] || [],
    viewCount: c.viewCount ?? 0,
    createdAt: c.createdAt.toISOString(),
  }));

  return Response.json({ comparisons: data, total, page, limit });
}