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

import {
  APIErrorCode,
  APIException,
  isLoginUserRequest,
  isUpdateUserRequest,
  type PaginatedData,
  validateRegisterUserRequest,
} from "../model/interfaces.ts";

import { createJWT, verifyPassword } from "../lib/jwt.ts";
import { type AuthContext, authMiddleware } from "../middleware/auth.ts";
import { parseOptionalAuth } from "../lib/auth.ts";
import { parsePagination } from "../lib/pagination.ts";
import {
  createUser,
  getInviteTree,
  getUserById,
  getUserByUsername,
  searchUsers,
  updateUser,
} from "../services/user-service.ts";
import { redeemInvite, validateInvite } from "../services/invite-service.ts";
import {
  requestPasswordReset,
  resetPassword,
} from "../services/password-reset-service.ts";
import { isEmailEnabled, sendEmail } from "../services/email-service.ts";
import {
  FROM_EMAIL,
  OG_SITE_NAME,
  VALIDATION,
  WELCOME_EMAIL_BODY,
} from "../config.ts";
import { marked } from "marked";
import { broadcastUserUpdated } from "../services/ws-service.ts";
import {
  getDumpsByUser,
  getVotedDumpsByUser,
} from "../services/dump-service.ts";
import { listPlaylistsByUser } from "../services/playlist-service.ts";
import {
  getFollowedPlaylistsByUser,
  getFollowedUsersByUser,
} from "../services/follow-service.ts";

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

// Register a new user (requires a valid invite token)
router.post("/register", async (ctx) => {
  const body = await ctx.request.body.json();

  const registerError = validateRegisterUserRequest(body);
  if (registerError) {
    throw new APIException(APIErrorCode.VALIDATION_ERROR, 400, registerError);
  }

  // Validate invite — throws 404/409 if bad
  const inviterId = await validateInvite(body.inviteToken);

  const user = await createUser(body, inviterId);

  // Mark invite as used only after the user row is committed
  try {
    redeemInvite(body.inviteToken);
  } catch (err) {
    console.error("[register] redeemInvite failed (user created):", err);
  }

  // Send welcome email (fire-and-forget)
  if (isEmailEnabled()) {
    const emailMarkdown = WELCOME_EMAIL_BODY
      .replaceAll("{{username}}", user.username)
      .replaceAll("{{site_name}}", OG_SITE_NAME);
    sendEmail({
      from: FROM_EMAIL,
      to: user.email,
      subject: `Welcome to ${OG_SITE_NAME}`,
      text: emailMarkdown,
      html: await marked(emailMarkdown),
    }).catch((err) => console.error("[register] welcome email failed:", err));
  }

  const authToken = await createJWT({
    userId: user.id,
    username: user.username,
    isAdmin: user.isAdmin,
  });

  const { passwordHash: _, ...publicUser } = user;
  ctx.response.status = 201;
  ctx.response.body = {
    success: true,
    data: { token: authToken, user: publicUser },
  };
});

// Login
router.post("/login", async (ctx) => {
  try {
    const body = await ctx.request.body.json();

    if (!isLoginUserRequest(body)) {
      throw new APIException(
        APIErrorCode.VALIDATION_ERROR,
        400,
        "Invalid request",
      );
    }

    const user = getUserByUsername(body.username);
    const valid = await verifyPassword(body.password, user.passwordHash);

    if (!valid) {
      throw new APIException(
        APIErrorCode.VALIDATION_ERROR,
        401,
        "Invalid username or password",
      );
    }

    const token = await createJWT({
      userId: user.id,
      username: user.username,
      isAdmin: user.isAdmin,
    });

    const { passwordHash: _, ...publicUser } = user;
    ctx.response.body = {
      success: true,
      data: {
        token,
        user: publicUser,
      },
    };
  } catch (err) {
    console.error(err);

    throw new APIException(APIErrorCode.SERVER_ERROR, 500, "Failed to login");
  }
});

// Get current user profile
router.get("/me", authMiddleware, (ctx: AuthContext) => {
  try {
    if (!ctx.state.user) {
      throw new APIException(
        APIErrorCode.UNAUTHORIZED,
        401,
        "Not authenticated",
      );
    }

    const { passwordHash: _, ...publicUser } = getUserById(
      ctx.state.user.userId,
    );

    ctx.response.body = {
      success: true,
      data: publicUser,
    };
  } catch (err) {
    console.error(err);

    throw new APIException(
      APIErrorCode.SERVER_ERROR,
      500,
      "Failed to fetch user profile",
    );
  }
});

// Request a password reset email (unauthenticated; always returns 200)
router.post("/request-password-reset", async (ctx) => {
  const body = await ctx.request.body.json();
  const email = typeof body?.email === "string" ? body.email.trim() : "";
  if (email) {
    await requestPasswordReset(email).catch((err) =>
      console.error("[request-password-reset]", err)
    );
  }
  ctx.response.body = { success: true };
});

// Consume a reset token and set a new password (unauthenticated)
router.post("/reset-password", async (ctx) => {
  const body = await ctx.request.body.json();
  const { token, newPassword } = (body ?? {}) as Record<string, unknown>;
  if (typeof token !== "string" || typeof newPassword !== "string") {
    throw new APIException(
      APIErrorCode.VALIDATION_ERROR,
      400,
      "Invalid request",
    );
  }
  await resetPassword(token, newPassword);
  ctx.response.body = { success: true };
});

// Change current user's password (requires current password verification)
router.post("/me/change-password", authMiddleware, async (ctx: AuthContext) => {
  const body = await ctx.request.body.json();
  const { currentPassword, newPassword } = (body ?? {}) as Record<
    string,
    unknown
  >;

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

  if (
    newPassword.length < VALIDATION.PASSWORD_MIN ||
    newPassword.length > VALIDATION.PASSWORD_MAX
  ) {
    throw new APIException(
      APIErrorCode.VALIDATION_ERROR,
      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(
      APIErrorCode.VALIDATION_ERROR,
      401,
      "Current password is incorrect",
    );
  }

  await updateUser(ctx.state.user.userId, { password: newPassword });
  ctx.response.body = { success: true };
});

// Update current user profile (description, etc.)
router.patch("/me", authMiddleware, async (ctx: AuthContext) => {
  const body = await ctx.request.body.json();
  if (!isUpdateUserRequest(body)) {
    throw new APIException(
      APIErrorCode.VALIDATION_ERROR,
      400,
      "Invalid request",
    );
  }
  const updated = await updateUser(ctx.state.user.userId, body);
  const { passwordHash: _, email: _email, ...publicUser } = updated;
  broadcastUserUpdated(publicUser);
  ctx.response.body = { success: true, data: publicUser };
});

// User search for @mention autocomplete
router.get("/search", (ctx) => {
  const q = (ctx.request.url.searchParams.get("q") ?? "").trim();
  const results = searchUsers(q, 8);
  ctx.response.body = { success: true, data: results };
});

// Public user profile by internal ID (used when only userId is available, e.g. dump.userId)
router.get("/by-id/:userId", (ctx) => {
  const user = getUserById(ctx.params.userId);
  const { passwordHash: _, email: _email, ...publicUser } = user;
  ctx.response.body = { success: true, data: publicUser };
});

// Followed users for a user (public)
router.get("/:username/followed-users", (ctx) => {
  const user = getUserByUsername(ctx.params.username);
  const { page, limit } = parsePagination(ctx.request.url.searchParams);
  const { items, total } = getFollowedUsersByUser(user.id, page, limit);
  ctx.response.body = {
    success: true,
    data: {
      items: items.map(({ passwordHash: _, email: _e, ...pub }) => pub),
      total,
      hasMore: page * limit < total,
    },
  };
});

// Followed playlists for a user (public only)
router.get("/:username/followed-playlists", (ctx) => {
  const user = getUserByUsername(ctx.params.username);
  const { page, limit } = parsePagination(ctx.request.url.searchParams);
  const { items, total } = getFollowedPlaylistsByUser(user.id, page, limit);
  ctx.response.body = {
    success: true,
    data: {
      items,
      total,
      hasMore: page * limit < total,
    } satisfies PaginatedData<typeof items[number]>,
  };
});

// Playlists by user (optional auth: include private only if requester === owner)
router.get("/:username/playlists", async (ctx) => {
  const user = getUserByUsername(ctx.params.username);
  const requestingUserId = await parseOptionalAuth(ctx);
  const { page, limit } = parsePagination(ctx.request.url.searchParams);
  const { items, total } = listPlaylistsByUser(
    user.id,
    requestingUserId,
    page,
    limit,
  );
  ctx.response.body = {
    success: true,
    data: {
      items,
      total,
      hasMore: page * limit < total,
    } satisfies PaginatedData<typeof items[number]>,
  };
});

// Invite tree for a user (public)
router.get("/:username/invitees", (ctx) => {
  const user = getUserByUsername(ctx.params.username);
  const tree = getInviteTree(user.id);
  ctx.response.body = { success: true, data: tree };
});

// Public user profile by username (no passwordHash)
router.get("/:username", (ctx) => {
  const user = getUserByUsername(ctx.params.username);
  const { passwordHash: _, email: _email, ...publicUser } = user;
  ctx.response.body = { success: true, data: publicUser };
});

// Dumps posted by user (optional auth: owner sees their private dumps)
router.get("/:username/dumps", async (ctx) => {
  const user = getUserByUsername(ctx.params.username);
  const requestingUserId = await parseOptionalAuth(ctx);
  const { page, limit } = parsePagination(ctx.request.url.searchParams);
  const includePrivate = requestingUserId === user.id;
  const { items, total } = getDumpsByUser(user.id, page, limit, includePrivate);
  ctx.response.body = {
    success: true,
    data: {
      items,
      total,
      hasMore: page * limit < total,
    } satisfies PaginatedData<typeof items[number]>,
  };
});

// Dumps upvoted by user (optional auth: hide private dump entries for non-owners)
router.get("/:username/votes", async (ctx) => {
  const user = getUserByUsername(ctx.params.username);
  const requestingUserId = await parseOptionalAuth(ctx);
  const { page, limit } = parsePagination(ctx.request.url.searchParams);
  const { items, total } = getVotedDumpsByUser(
    user.id,
    page,
    limit,
    requestingUserId,
  );
  ctx.response.body = {
    success: true,
    data: {
      items,
      total,
      hasMore: page * limit < total,
    } satisfies PaginatedData<typeof items[number]>,
  };
});

export default router;