/**
 * Backend
 */

export interface RichContent {
  type: string;
  url: string;
  siteName?: string;
  title?: string;
  description?: string;
  thumbnailUrl?: string;
  videoId?: string;
  embedUrl?: string;
}

export interface Dump {
  id: string;
  kind: "url" | "file";
  title: string;
  comment?: string;
  userId: string;
  createdAt: Date;
  url?: string;
  richContent?: RichContent;
  fileName?: string;
  fileMime?: string;
  fileSize?: number;
  voteCount: number;
  commentCount: number;
  isPrivate: boolean;
}

/**
 * Authentication
 */

export interface User {
  id: string;
  username: string;
  passwordHash: string;
  isAdmin: boolean;
  createdAt: Date;
  avatarMime?: string;
}

export interface LoginUserRequest {
  username: string;
  password: string;
}

export interface RegisterUserRequest {
  username: string;
  password: string;
}

export interface UpdateUserRequest {
  username?: string;
  password?: string;
  isAdmin?: boolean;
}

export function isLoginUserRequest(obj: unknown): obj is LoginUserRequest {
  return !!obj && typeof obj === "object" &&
    "username" in obj && typeof obj.username === "string" &&
    "password" in obj && typeof obj.password === "string";
}

export function isRegisterUserRequest(
  obj: unknown,
): obj is RegisterUserRequest {
  return !!obj && typeof obj === "object" &&
    "username" in obj && typeof obj.username === "string" &&
    "password" in obj && typeof obj.password === "string";
}

export function isUpdateUserRequest(obj: unknown): obj is UpdateUserRequest {
  return !!obj && typeof obj === "object" &&
    (!("username" in obj) || typeof obj.username === "string") &&
    (!("password" in obj) || typeof obj.password === "string") &&
    (!("isAdmin" in obj) || typeof obj.isAdmin === "boolean");
}

export interface AuthResponse {
  token: string;
  user: User;
}

export interface AuthPayload {
  userId: string;
  username: string;
  isAdmin: boolean;
  exp: number;
}

export function isAuthPayload(obj: unknown): obj is AuthPayload {
  return !!obj &&
    typeof obj === "object" &&
    "userId" in obj && typeof obj.userId === "string" &&
    "username" in obj && typeof obj.username === "string" &&
    "isAdmin" in obj && typeof obj.isAdmin === "boolean" &&
    "exp" in obj && typeof obj.exp === "number";
}

/**
 * API
 */

export enum APIErrorCode {
  BAD_REQUEST = "BAD_REQUEST",
  NOT_FOUND = "NOT_FOUND",
  SERVER_ERROR = "SERVER_ERROR",
  TIMEOUT = "TIMEOUT",
  UNAUTHORIZED = "UNAUTHORIZED",
  VALIDATION_ERROR = "VALIDATION_ERROR",
}

export interface APIError {
  code: APIErrorCode;
  message: string;
}

export interface APISuccess<T> {
  success: true;
  data: T;
  error?: never;
}

export interface APIFailure {
  success: false;
  data?: never;
  error: APIError;
}

export type APIResponse<T> = APISuccess<T> | APIFailure;

export interface PaginatedData<T> {
  items: T[];
  total: number;
  hasMore: boolean;
}

export class APIException extends Error {
  readonly code: APIErrorCode;
  readonly status: number;

  constructor(code: APIErrorCode, status: number, message: string) {
    super(message);
    this.code = code;
    this.status = status;
  }
}

/**
 * Comments
 */

export interface Comment {
  id: string;
  dumpId: string;
  userId: string;
  parentId?: string;
  body: string;
  createdAt: Date;
  deleted: boolean;
  authorUsername: string;
  authorAvatarMime?: string;
}

export interface CreateCommentRequest {
  body: string;
  parentId?: string;
}

export function isCreateCommentRequest(obj: unknown): obj is CreateCommentRequest {
  if (!obj || typeof obj !== "object") return false;
  const o = obj as Record<string, unknown>;
  return typeof o.body === "string" && (o.body as string).trim().length > 0 &&
    (!("parentId" in o) || typeof o.parentId === "string" || o.parentId === null);
}

/**
 * Playlists
 */

export interface Playlist {
  id: string;
  userId: string;
  title: string;
  description?: string;
  isPublic: boolean;
  createdAt: Date;
  imageMime?: string;
  dumpCount?: number;
}

export interface PlaylistWithDumps extends Playlist {
  dumps: Dump[];
}

export interface PlaylistMembership {
  playlist: Playlist;
  hasDump: boolean;
}

export interface CreatePlaylistRequest {
  title: string;
  description?: string;
  isPublic: boolean;
}

export interface UpdatePlaylistRequest {
  title?: string;
  description?: string;
  isPublic?: boolean;
}

export interface ReorderPlaylistRequest {
  dumpIds: string[];
}

export function isCreatePlaylistRequest(
  obj: unknown,
): obj is CreatePlaylistRequest {
  return !!obj && typeof obj === "object" &&
    "title" in obj && typeof obj.title === "string" &&
    (!("description" in obj) || typeof obj.description === "string" ||
      obj.description === null) &&
    "isPublic" in obj && typeof obj.isPublic === "boolean";
}

export function isUpdatePlaylistRequest(
  obj: unknown,
): obj is UpdatePlaylistRequest {
  return !!obj && typeof obj === "object" &&
    (!("title" in obj) || typeof obj.title === "string") &&
    (!("description" in obj) || typeof obj.description === "string" ||
      obj.description === null) &&
    (!("isPublic" in obj) || typeof obj.isPublic === "boolean");
}

export function isReorderPlaylistRequest(
  obj: unknown,
): obj is ReorderPlaylistRequest {
  return !!obj && typeof obj === "object" &&
    "dumpIds" in obj && Array.isArray(obj.dumpIds) &&
    (obj.dumpIds as unknown[]).every((id) => typeof id === "string");
}

/**
 * Request DTOs
 */

export interface CreateUrlDumpRequest {
  url: string;
  comment?: string;
  isPrivate?: boolean;
}

export function isCreateUrlDumpRequest(
  obj: unknown,
): obj is CreateUrlDumpRequest {
  return !!obj &&
    typeof obj === "object" &&
    "url" in obj && typeof obj.url === "string" &&
    (!("comment" in obj) ||
      typeof obj.comment === "string" || obj.comment === null) &&
    (!("isPrivate" in obj) || typeof obj.isPrivate === "boolean");
}

export interface UpdateDumpRequest {
  url?: string;
  comment?: string;
  isPrivate?: boolean;
}

export function isUpdateDumpRequest(obj: unknown): obj is UpdateDumpRequest {
  return !!obj &&
    typeof obj === "object" &&
    (!("url" in obj) || typeof obj.url === "string" || obj.url === null) &&
    (!("comment" in obj) ||
      typeof obj.comment === "string" || obj.comment === null) &&
    (!("isPrivate" in obj) || typeof obj.isPrivate === "boolean");
}

/**
 * WebSockets
 */

export interface VoteCastMessage {
  type: "vote_cast";
  dumpId: string;
  userId: string;
}

export interface VoteAckMessageFailure {
  type: "vote_ack";
  dumpId: string;
  success: false;
  error: APIError;
}

export interface VoteAckMessageSuccess {
  type: "vote_ack";
  dumpId: string;
  action: "cast" | "remove";
  success: true;
  voteCount: number;
  error?: never;
}

export type VoteAckMessage = VoteAckMessageSuccess | VoteAckMessageFailure;

export interface VoteRemoveMessage {
  type: "vote_remove";
  dumpId: string;
}

export interface VotesUpdateMessage {
  type: "votes_update";
  dumpId: string;
  voteCount: number;
}

export interface OnlineUser {
  userId: string;
  username: string;
  hasAvatar: boolean;
}

export interface WelcomeMessage {
  type: "welcome";
  users: OnlineUser[];
  myVotes: string[];
}

export interface PresenceUpdateMessage {
  type: "presence_update";
  users: OnlineUser[];
}

export interface PingMessage {
  type: "ping";
}

export interface PongMessage {
  type: "pong";
}