import "@supabase/functions-js/edge-runtime.d.ts";
import { z } from "zod";
import { corsHeaders } from "../_shared/cors.ts";
import { HttpError, sendError, sendSuccess } from "../_shared/utils.ts";

console.log("Starting buscar-bibliografia function");

type GoogleBooksVolume = Record<string, unknown>;

interface GoogleBooksVolumesListResponse {
  kind?: string;
  totalItems?: number;
  items?: GoogleBooksVolume[];
}

const SearchTermsSchema = z
  .object({
    q: z.string().min(1, "q es requerido"),
    maxResults: z.number().int().min(0).max(40),
    orderBy: z.enum(["newest", "relevance"]).optional(),
  })
  .passthrough();

const BodySchema = z
  .object({
    searchTerms: SearchTermsSchema,
  })
  .strict();

type BuscarBibliografiaRequest = z.infer<typeof BodySchema>;

function formatZodIssues(issues: z.ZodIssue[]): string {
  return issues
    .map((issue, i) => {
      const path = issue.path.length ? issue.path.join(".") : "(root)";
      return `${i + 1}. ${path}: ${issue.message}`;
    })
    .join("\n");
}

function buildUrlWithSearchTerms(
  baseUrl: string,
  searchTerms: Record<string, unknown>,
): string {
  const url = new URL(baseUrl);
  for (const [key, value] of Object.entries(searchTerms)) {
    if (value === undefined || value === null) continue;
    if (Array.isArray(value)) {
      for (const v of value) {
        if (v === undefined || v === null) continue;
        url.searchParams.append(key, String(v));
      }
      continue;
    }
    url.searchParams.set(key, String(value));
  }
  return url.toString();
}

Deno.serve(async (req: Request): Promise<Response> => {
  const url = new URL(req.url);
  const functionName = url.pathname.split("/").pop();
  console.log(
    `[${new Date().toISOString()}][${functionName}]: Request received`,
  );

  if (req.method === "OPTIONS") {
    return new Response(null, { status: 204, headers: corsHeaders });
  }

  try {
    if (req.method !== "POST") {
      throw new HttpError(405, "Método no permitido.", "METHOD_NOT_ALLOWED", {
        method: req.method,
      });
    }

    const contentType = (req.headers.get("content-type") || "").toLowerCase();
    if (!contentType.includes("application/json")) {
      throw new HttpError(
        415,
        "Content-Type no soportado.",
        "UNSUPPORTED_MEDIA_TYPE",
        { contentType, expected: "application/json" },
      );
    }

    let rawBody: unknown;
    try {
      rawBody = await req.json();
    } catch (e) {
      throw new HttpError(400, "Body JSON inválido.", "INVALID_JSON", {
        cause: e,
      });
    }

    const parsed = BodySchema.safeParse(rawBody);
    if (!parsed.success) {
      throw new HttpError(
        422,
        formatZodIssues(parsed.error.issues),
        "VALIDATION_ERROR",
        parsed.error,
      );
    }

    const body: BuscarBibliografiaRequest = parsed.data;

    const GOOGLE_API_KEY = Deno.env.get("GOOGLE_API_KEY");
    if (!GOOGLE_API_KEY) {
      throw new HttpError(
        500,
        "Configuración del servidor incompleta.",
        "MISSING_ENV",
        { missing: ["GOOGLE_API_KEY"] },
      );
    }

    const baseUrl = "https://www.googleapis.com/books/v1/volumes";
    const requestUrl = buildUrlWithSearchTerms(baseUrl, {
      ...body.searchTerms,
      key: GOOGLE_API_KEY,
    });

    const googleResp = await fetch(requestUrl, {
      method: "GET",
      headers: {
        Accept: "application/json",
      },
    });

    if (!googleResp.ok) {
      const text = await googleResp.text().catch(() => "");
      throw new HttpError(
        502,
        "Error al consultar Google Books.",
        "GOOGLE_BOOKS_REQUEST_FAILED",
        {
          status: googleResp.status,
          statusText: googleResp.statusText,
          body: text || null,
        },
      );
    }

    const data = (await googleResp.json()) as GoogleBooksVolumesListResponse;
    const items = Array.isArray(data?.items) ? data.items : [];

    return sendSuccess(items);
  } catch (error) {
    if (error instanceof HttpError) {
      console.error(
        `[${new Date().toISOString()}][${functionName}] ⚠️ Handled Error:`,
        {
          message: error.message,
          code: error.code,
          internalDetails: error.internalDetails || "N/A",
        },
      );
      return sendError(error.status, error.message, error.code);
    }

    const unexpectedError = error instanceof Error
      ? error
      : new Error(String(error));

    console.error(
      `[${
        new Date().toISOString()
      }][${functionName}] 💥 CRITICAL UNHANDLED ERROR:`,
      unexpectedError.stack || unexpectedError.message,
    );

    return sendError(
      500,
      "Ocurrió un error inesperado en el servidor.",
      "INTERNAL_SERVER_ERROR",
    );
  }
});

/* To invoke locally:

  1. Run `supabase start` (see: https://supabase.com/docs/reference/cli/supabase-start)
  2. Make an HTTP request:

  curl -i --location --request POST 'http://127.0.0.1:54321/functions/v1/buscar-bibliografia' \
    --header 'Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJzdXBhYmFzZS1kZW1vIiwicm9sZSI6ImFub24iLCJleHAiOjE5ODM4MTI5OTZ9.CRXP1A7WOeoJeXxjNni43kdQwgnWNReilDMblYTn_I0' \
    --header 'Content-Type: application/json' \
    --data '{"name":"Functions"}'

*/