/**
 * Serves the categories dumps are filed under and their feeds, and changes them
 * for those with `category:manage`.
 *
 * - `GET /api/categories` — public. Answers every category, in order.
 * - `GET /api/categories/:slug` — public. Answers one category.
 * - `GET /api/categories/:slug/dumps?page=&limit=` — optional sign-in. Answers
 *   a page of its dumps, newest first, with the caller's private ones.
 * - `POST /api/categories` — permission `category:manage`. Creates a category.
 * - `PUT /api/categories/:id` — permission `category:manage`. Updates a
 *   category.
 * - `DELETE /api/categories/:id` — permission `category:manage`. Deletes a
 *   category; its dumps stay.
 *
 * @module
 */

import { Router } from "@oak/oak";

import { type APIResponse, type PaginatedData } from "../../shared/api.ts";
import { APIException } from "../lib/api-exception.ts";
import type { Category } from "../../shared/category.ts";
import type { Dump } from "../../shared/dump.ts";
import {
  isCreateCategoryRequest,
  isUpdateCategoryRequest,
} from "../validators/category.ts";

import { authMiddleware, requirePermission } from "../middleware/auth.ts";
import { parseOptionalAuth } from "../lib/auth.ts";
import { parsePagination } from "../lib/pagination.ts";
import {
  createCategory,
  deleteCategory,
  getCategoryBySlug,
  listCategories,
  listDumpsByCategory,
  updateCategory,
} from "../services/category-service.ts";

/**
 * Mounted by `api/main.ts` behind the error, Open Graph and CORS middleware.
 * An `APIException` thrown by a handler becomes the JSON error response there.
 */
const router: Router = new Router({ prefix: "/api/categories" });

router.get("/", (ctx) => {
  const responseBody: APIResponse<Category[]> = {
    success: true,
    data: listCategories(),
  };
  ctx.response.body = responseBody;
});

router.get("/:slug", (ctx) => {
  const category = getCategoryBySlug(ctx.params.slug);
  const responseBody: APIResponse<Category> = {
    success: true,
    data: category,
  };
  ctx.response.body = responseBody;
});

router.get("/:slug/dumps", async (ctx) => {
  const requestingUserId = await parseOptionalAuth(ctx) ?? undefined;
  const { page, limit } = parsePagination(ctx.request.url.searchParams);
  const { items, hasMore } = listDumpsByCategory(
    ctx.params.slug,
    page,
    limit,
    requestingUserId,
  );
  const responseBody: APIResponse<PaginatedData<Dump>> = {
    success: true,
    data: { items, hasMore },
  };
  ctx.response.body = responseBody;
});

router.post(
  "/",
  authMiddleware,
  requirePermission("category:manage"),
  async (ctx) => {
    const body: unknown = await ctx.request.body.json();
    if (!isCreateCategoryRequest(body)) {
      throw new APIException(400, "Invalid category data");
    }
    const category = createCategory(body);
    const responseBody: APIResponse<Category> = {
      success: true,
      data: category,
    };
    ctx.response.status = 201;
    ctx.response.body = responseBody;
  },
);

router.put(
  "/:id",
  authMiddleware,
  requirePermission("category:manage"),
  async (ctx) => {
    const body: unknown = await ctx.request.body.json();
    if (!isUpdateCategoryRequest(body)) {
      throw new APIException(400, "Invalid category data");
    }
    const category = updateCategory(ctx.params.id, body);
    const responseBody: APIResponse<Category> = {
      success: true,
      data: category,
    };
    ctx.response.body = responseBody;
  },
);

router.delete(
  "/:id",
  authMiddleware,
  requirePermission("category:manage"),
  (ctx) => {
    deleteCategory(ctx.params.id);
    const responseBody: APIResponse<null> = { success: true, data: null };
    ctx.response.body = responseBody;
  },
);

export default router;