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

import {
  APIErrorCode,
  APIException,
  type APIResponse,
  type Dump,
  isCreateUrlDumpRequest,
  isUpdateDumpRequest,
  type PaginatedData,
} from "../model/interfaces.ts";

import { authMiddleware } from "../middleware/auth.ts";
import { can } from "../lib/permissions.ts";
import { parseOptionalAuth } from "../lib/auth.ts";
import { parsePagination } from "../lib/pagination.ts";
import { validateImageUpload } from "../lib/upload.ts";
import { THUMBNAILS_DIR } from "../config.ts";
import {
  createFileDump,
  createUrlDump,
  deleteDump,
  getDump,
  listDumps,
  refreshDumpMetadata,
  removeDumpThumbnail,
  replaceFileDump,
  setDumpThumbnail,
  updateDump,
} from "../services/dump-service.ts";
import { getDumpVoters } from "../services/vote-service.ts";
import { getRelatedDumps } from "../services/backlink-service.ts";

const router = new Router({ prefix: "/api/dumps" });

router.post(
  "/",
  authMiddleware,
  async (ctx) => {
    const userId = ctx.state.user.userId;
    const contentType = ctx.request.headers.get("content-type") ?? "";

    let dump: Dump;

    if (contentType.includes("multipart/form-data")) {
      const formData = await ctx.request.body.formData();
      const file = formData.get("file");
      const comment = formData.get("comment");
      const title = formData.get("title");
      const isPrivate = formData.get("isPrivate") === "true";

      if (!(file instanceof File)) {
        throw new APIException(
          APIErrorCode.VALIDATION_ERROR,
          400,
          "A file is required",
        );
      }

      dump = await createFileDump(
        file,
        typeof comment === "string" && comment ? comment : undefined,
        userId,
        isPrivate,
        typeof title === "string" && title ? title : undefined,
      );
    } else {
      const body = await ctx.request.body.json();

      if (!isCreateUrlDumpRequest(body)) {
        throw new APIException(
          APIErrorCode.VALIDATION_ERROR,
          400,
          "Invalid dump data",
        );
      }

      dump = await createUrlDump(body, userId);
    }

    const responseBody: APIResponse<Dump> = { success: true, data: dump };
    ctx.response.status = 201;
    ctx.response.body = responseBody;
  },
);

router.get("/:dumpId", async (ctx) => {
  const requestingUserId = await parseOptionalAuth(ctx) ?? undefined;
  const dump = getDump(ctx.params.dumpId, requestingUserId);
  const responseBody: APIResponse<Dump> = { success: true, data: dump };
  ctx.response.body = responseBody;
});

router.get("/:dumpId/voters", async (ctx) => {
  const requestingUserId = await parseOptionalAuth(ctx) ?? undefined;
  const dump = getDump(ctx.params.dumpId, requestingUserId);
  const { page, limit } = parsePagination(ctx.request.url.searchParams);
  const { items, total } = getDumpVoters(dump.id, page, limit);
  ctx.response.body = {
    success: true,
    data: {
      items: items.map(({ passwordHash: _, email: _e, ...pub }) => pub),
      total,
      hasMore: page * limit < total,
    },
  };
});

router.get("/:dumpId/related", async (ctx) => {
  const requestingUserId = await parseOptionalAuth(ctx) ?? undefined;
  const dump = getDump(ctx.params.dumpId, requestingUserId);
  const related = getRelatedDumps(dump.id, requestingUserId);
  const responseBody: APIResponse<Dump[]> = { success: true, data: related };
  ctx.response.body = responseBody;
});

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

router.put("/:dumpId/file", authMiddleware, async (ctx) => {
  const dumpId = ctx.params.dumpId;
  const userId = ctx.state.user.userId;

  const dump = getDump(dumpId, userId);
  if (userId !== dump.userId && !can(ctx.state.user, "dump:moderate")) {
    throw new APIException(
      APIErrorCode.UNAUTHORIZED,
      403,
      "Not authorized to update dump",
    );
  }

  const formData = await ctx.request.body.formData();
  const file = formData.get("file");
  const comment = formData.get("comment");
  const title = formData.get("title");

  if (!(file instanceof File)) {
    throw new APIException(
      APIErrorCode.VALIDATION_ERROR,
      400,
      "A file is required",
    );
  }

  const updatedDump = await replaceFileDump(
    dumpId,
    file,
    typeof comment === "string" && comment ? comment : undefined,
    typeof title === "string" && title ? title : undefined,
  );
  const responseBody: APIResponse<Dump> = { success: true, data: updatedDump };
  ctx.response.body = responseBody;
});

router.put("/:dumpId", authMiddleware, async (ctx) => {
  const dumpId = ctx.params.dumpId;
  const userId = ctx.state.user.userId;
  const body = await ctx.request.body.json();

  if (!isUpdateDumpRequest(body)) {
    throw new APIException(
      APIErrorCode.VALIDATION_ERROR,
      422,
      "Erroneous user input",
    );
  }

  const dump = getDump(dumpId, userId);

  if (userId !== dump.userId && !can(ctx.state.user, "dump:moderate")) {
    throw new APIException(
      APIErrorCode.UNAUTHORIZED,
      403,
      "Not authorized to update dump",
    );
  }

  const updatedDump = await updateDump(dumpId, body);
  const responseBody: APIResponse<Dump> = { success: true, data: updatedDump };
  ctx.response.body = responseBody;
});

router.put("/:dumpId/thumbnail", authMiddleware, async (ctx) => {
  const dumpId = ctx.params.dumpId;
  const userId = ctx.state.user.userId;

  const dump = getDump(dumpId, userId);
  if (userId !== dump.userId && !can(ctx.state.user, "dump:moderate")) {
    throw new APIException(
      APIErrorCode.UNAUTHORIZED,
      403,
      "Not authorized to update dump",
    );
  }

  const formData = await ctx.request.body.formData();
  const file = formData.get("file");

  if (!(file instanceof File)) {
    throw new APIException(
      APIErrorCode.VALIDATION_ERROR,
      400,
      "Missing file field",
    );
  }

  const data = new Uint8Array(await file.arrayBuffer());
  const mime = validateImageUpload(data);

  // DB update first (resolves slug → id), then file write.
  const updatedDump = setDumpThumbnail(dump.id, mime);
  const filePath = `${THUMBNAILS_DIR}/${dump.id}-custom`;
  await Deno.mkdir(THUMBNAILS_DIR, { recursive: true });
  try {
    await Deno.writeFile(filePath, data);
  } catch (err) {
    await Deno.remove(filePath).catch(() => {});
    throw err;
  }

  const responseBody: APIResponse<Dump> = { success: true, data: updatedDump };
  ctx.response.body = responseBody;
});

router.delete("/:dumpId/thumbnail", authMiddleware, async (ctx) => {
  const dumpId = ctx.params.dumpId;
  const userId = ctx.state.user.userId;

  const dump = getDump(dumpId, userId);
  if (userId !== dump.userId && !can(ctx.state.user, "dump:moderate")) {
    throw new APIException(
      APIErrorCode.UNAUTHORIZED,
      403,
      "Not authorized to update dump",
    );
  }

  const updatedDump = await removeDumpThumbnail(dump.id);
  const responseBody: APIResponse<Dump> = { success: true, data: updatedDump };
  ctx.response.body = responseBody;
});

router.post("/:dumpId/refresh-metadata", authMiddleware, async (ctx) => {
  const dumpId = ctx.params.dumpId;
  const userId = ctx.state.user.userId;
  const dump = getDump(dumpId, userId);

  if (userId !== dump.userId && !can(ctx.state.user, "dump:moderate")) {
    throw new APIException(
      APIErrorCode.UNAUTHORIZED,
      403,
      "Not authorized to update dump",
    );
  }

  const updatedDump = await refreshDumpMetadata(dumpId);
  const responseBody: APIResponse<Dump> = { success: true, data: updatedDump };
  ctx.response.body = responseBody;
});

router.delete("/:dumpId", authMiddleware, async (ctx) => {
  const dumpId = ctx.params.dumpId;
  const userId = ctx.state.user.userId;
  const dump = getDump(dumpId, userId);

  if (userId !== dump.userId && !can(ctx.state.user, "dump:moderate")) {
    throw new APIException(
      APIErrorCode.UNAUTHORIZED,
      403,
      "Not authorized to delete dump",
    );
  }

  await deleteDump(dumpId);

  const responseBody: APIResponse<null> = { success: true, data: null };
  ctx.response.body = responseBody;
});

export default router;