/**
 * Serves the caller's own account: their user, settings, password and media
 * token, and which of their playlists hold a dump. What they follow, their
 * feed and their notifications are under `/api/me` too, served by
 * `routes/follows.ts` and `routes/notifications.ts`, and their avatar by
 * `routes/avatars.ts`.
 *
 * - `GET /api/me` — signed in. Answers the caller's own user.
 * - `PATCH /api/me` — signed in. Changes the caller's description, email and
 *   username, and answers their user. A new username keeps the old one as an
 *   alias, at most once in 30 days but for those with `user:manage`.
 * - `GET /api/me/media-token` — signed in. Answers a media token, for a
 *   session that predates them.
 * - `GET /api/me/settings` — signed in. Answers the caller's settings.
 * - `PATCH /api/me/settings` — signed in. Changes some of the caller's
 *   settings, and answers them all.
 * - `PUT /api/me/password` — signed in, with the current password. Sets a new
 *   one, ending every other session, and answers fresh tokens.
 * - `GET /api/me/playlists?contains=:dumpId` — signed in. Answers each of the
 *   caller's playlists and whether it holds the dump.
 *
 * @module
 */

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

import { type APIResponse } from "../../shared/api.ts";
import { APIException } from "../lib/api-exception.ts";
import type {
  AuthTokens,
  MediaTokenResponse,
  SelfUser,
} from "../../shared/user.ts";
import type { PlaylistMembership } from "../../shared/playlist.ts";
import type { UserSettings } from "../../shared/settings.ts";
import { fieldOf, isUpdateUserRequest } from "../validators/user.ts";
import { isUpdateSettingsRequest } from "../validators/settings.ts";
import { toPublicUser, toSelfUser } from "../model/user.ts";
import { createMediaToken, issueTokens } from "../lib/jwt.ts";
import { verifyPassword } from "../lib/password.ts";
import { can } from "../lib/permissions.ts";
import { type AuthContext, authMiddleware } from "../middleware/auth.ts";
import {
  getUserById,
  renameUser,
  updateUser,
} from "../services/user-service.ts";
import { getSettings, updateSettings } from "../services/settings-service.ts";
import { getPlaylistMembershipsForDump } from "../services/playlist-service.ts";
import {
  broadcastUserUpdated,
  updateClientUsername,
} from "../services/ws-service.ts";
import { VALIDATION } from "../../shared/validation.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/me" });

router.get("/", authMiddleware, (ctx: AuthContext) => {
  const responseBody: APIResponse<SelfUser> = {
    success: true,
    data: toSelfUser(getUserById(ctx.state.user.userId)),
  };
  ctx.response.body = responseBody;
});

router.patch("/", authMiddleware, async (ctx: AuthContext) => {
  const body: unknown = await ctx.request.body.json();
  if (!isUpdateUserRequest(body)) {
    throw new APIException(400, "Invalid request");
  }
  const userId = ctx.state.user.userId;
  // Only these fields: a stolen token alone must not change the role or the
  // password, which needs the current one. The rename first: it is the change
  // most likely refused, and a refusal should leave the rest as it was.
  if (body.username !== undefined) {
    const renamed = renameUser(
      userId,
      body.username,
      can(ctx.state.user, "user:manage"),
    );
    updateClientUsername(userId, renamed.username);
  }
  const updated = await updateUser(userId, {
    description: body.description,
    email: body.email,
  });
  broadcastUserUpdated(toPublicUser(updated));
  const responseBody: APIResponse<SelfUser> = {
    success: true,
    data: toSelfUser(updated),
  };
  ctx.response.body = responseBody;
});

router.get("/media-token", authMiddleware, async (ctx: AuthContext) => {
  const responseBody: APIResponse<MediaTokenResponse> = {
    success: true,
    data: { mediaToken: await createMediaToken(ctx.state.user.userId) },
  };
  ctx.response.body = responseBody;
});

router.get("/settings", authMiddleware, (ctx: AuthContext) => {
  const responseBody: APIResponse<UserSettings> = {
    success: true,
    data: getSettings(ctx.state.user.userId),
  };
  ctx.response.body = responseBody;
});

router.patch("/settings", authMiddleware, async (ctx: AuthContext) => {
  const body: unknown = await ctx.request.body.json();
  if (!isUpdateSettingsRequest(body)) {
    throw new APIException(400, "Invalid settings");
  }
  const responseBody: APIResponse<UserSettings> = {
    success: true,
    data: updateSettings(ctx.state.user.userId, body),
  };
  ctx.response.body = responseBody;
});

router.put("/password", authMiddleware, async (ctx: AuthContext) => {
  const body: unknown = await ctx.request.body.json();
  const currentPassword = fieldOf(body, "currentPassword");
  const newPassword = fieldOf(body, "newPassword");

  if (typeof currentPassword !== "string" || typeof newPassword !== "string") {
    throw new APIException(400, "Invalid request");
  }

  if (
    newPassword.length < VALIDATION.PASSWORD_MIN ||
    newPassword.length > VALIDATION.PASSWORD_MAX
  ) {
    throw new APIException(
      400,
      `Password must be ${VALIDATION.PASSWORD_MIN}–${VALIDATION.PASSWORD_MAX} characters`,
    );
  }

  const user = getUserById(ctx.state.user.userId);
  const valid = await verifyPassword(currentPassword, user.passwordHash);
  if (!valid) {
    throw new APIException(403, "Current password is incorrect");
  }

  // Changing the password revokes every token issued before it, this
  // session's included, so hand back fresh ones for the client to keep.
  const updated = await updateUser(ctx.state.user.userId, {
    password: newPassword,
  });
  const responseBody: APIResponse<AuthTokens> = {
    success: true,
    data: await issueTokens(updated),
  };
  ctx.response.body = responseBody;
});

router.get("/playlists", authMiddleware, (ctx: AuthContext) => {
  const dumpId = ctx.request.url.searchParams.get("contains");
  if (!dumpId) throw new APIException(400, "contains is required");
  const responseBody: APIResponse<PlaylistMembership[]> = {
    success: true,
    data: getPlaylistMembershipsForDump(dumpId, ctx.state.user.userId),
  };
  ctx.response.body = responseBody;
});

export default router;