import { serve } from "bun";
import packages from "../database/packages.json";
import programs from "../database/programs.json";

serve({
  port: 3000,
  fetch(req) {
    const url = new URL(req.url);
    const pathname = url.pathname;
    const q = url.searchParams.get("q")?.trim().toLowerCase();
    const filter = url.searchParams.get("filter")?.trim().toLowerCase();

    const corsHeaders = {
      "Content-Type": "application/json",
      "Access-Control-Allow-Origin": "*",
    };

    // CORS preflight handling
    if (req.method === "OPTIONS") {
      return new Response(null, {
        status: 204,
        headers: {
          "Access-Control-Allow-Origin": "*",
          "Access-Control-Allow-Methods": "GET, POST, OPTIONS",
          "Access-Control-Allow-Headers": "Content-Type",
        },
      });
    }

    if (pathname === "/api/searchPackages") {
      const results = packages.filter(
        ({ name, full_name, description, topics }) => {
          if (
            filter &&
            !topics?.some((t: string) => t.toLowerCase() === filter)
          )
            return false;
          if (!q) return true;
          return [name, full_name, description, ...(topics || [])].some(
            (field: string) => field?.toLowerCase().includes(q),
          );
        },
      );

      return new Response(JSON.stringify(results.slice(0, 25)), {
        status: 200,
        headers: corsHeaders,
      });
    }

    if (pathname === "/api/searchProgams") {
      const results = programs.filter(({ full_name, description, topics }) => {
        if (filter && !topics?.some((t: string) => t.toLowerCase() === filter))
          return false;
        if (!q) return true;
        return [full_name, description, ...(topics || [])].some(
          (field: string) => field?.toLowerCase().includes(q),
        );
      });

      return new Response(JSON.stringify(results.slice(0, 25)), {
        status: 200,
        headers: corsHeaders,
      });
    }

    if (pathname === "/api/infiniteScrollPackages") {
      const pageNumberParam = url.searchParams.get("pageNumber");
      const pageNumber = parseInt(pageNumberParam || "0", 10);

      if (isNaN(pageNumber) || pageNumber < 0) {
        return new Response(JSON.stringify({ error: "Invalid page number" }), {
          status: 400,
          headers: corsHeaders,
        });
      }

      const lowerLimit = pageNumber * 10;
      const scrollResults = packages.slice(lowerLimit, lowerLimit + 10);

      return new Response(JSON.stringify(scrollResults), {
        status: 200,
        headers: corsHeaders,
      });
    }

    if (pathname === "/api/infiniteScrollPrograms") {
      const section = url.searchParams.get("section");
      const [ll, ul] = (url.searchParams.get("range") || "")
        .split("..")
        .map(Number);

      if (!section || isNaN(ll) || isNaN(ul)) {
        return new Response(JSON.stringify([]), {
          status: 400,
          headers: corsHeaders,
        });
      }

      const getSortedResponse = (sortFn: Function) =>
        new Response(JSON.stringify([...programs].sort(sortFn).slice(ll, ul)), {
          status: 200,
          headers: corsHeaders,
        });

      if (section === "mostUsed") {
        return getSortedResponse(
          (a: any, b: any) => b.stargazers_count - a.stargazers_count,
        );
      }

      if (section === "latestRepos") {
        return getSortedResponse(
          (a: any, b: any) =>
            new Date(b.created_at).getTime() - new Date(a.created_at).getTime(),
        );
      }

      return new Response(JSON.stringify([]), {
        status: 400,
        headers: corsHeaders,
      });
    }

    return new Response("Not Found", {
      status: 404,
      headers: { "Access-Control-Allow-Origin": "*" },
    });
  },
});