/**
 * The `users` table: its row type, its guard, its mappers to and from the
 * stored {@link User}, and the views of a user the API sends.
 *
 * @module
 */

import type { SQLOutputValue } from "node:sqlite";
import {
  isRole,
  type PublicUser,
  type Role,
  type SelfUser,
} from "../../shared/user.ts";

/** A user as stored: what they see of themselves, plus the password hash. */
export interface User extends SelfUser {
  /** The scrypt hash of the password, as `hash.salt`. */
  passwordHash: string;
}

/** Returns what anyone may see of `user`: no hash, no email. */
export function toPublicUser(
  { passwordHash: _, email: _email, ...user }: User,
): PublicUser {
  return user;
}

/** Returns what `user` sees of themselves: everything but the hash. */
export function toSelfUser({ passwordHash: _, ...user }: User): SelfUser {
  return user;
}

/** A row of the `users` table. */
export interface UserRow {
  /** The user's id. */
  id: string;
  /** The user's name, unique. */
  username: string;
  /** The scrypt hash of the password, as `hash.salt`. */
  password_hash: string;
  /** The user's role. */
  role: Role;
  /** When the user registered. */
  created_at: string;
  /** When the profile was last changed, if ever. */
  updated_at: string | null;
  /** The avatar's type, null without one. */
  avatar_mime: string | null;
  /** The user's profile text, in Markdown. */
  description: string | null;
  /** The id of the user whose invite they registered with. */
  invited_by: string | null;
  /**
   * The inviter's name; present only when the query joins it (`LEFT JOIN users
   * i ON i.id = u.invited_by`).
   */
  invited_by_username: string | null;
  /** The user's email address. */
  email: string;
  /** Any other column the query selects. */
  [key: string]: SQLOutputValue;
}

/** Checks whether `obj` is a {@link UserRow}. */
export function isUserRow(obj: unknown): obj is UserRow {
  return !!obj &&
    typeof obj === "object" &&
    "id" in obj && typeof obj.id === "string" &&
    "username" in obj && typeof obj.username === "string" &&
    "password_hash" in obj && typeof obj.password_hash === "string" &&
    "role" in obj && isRole(obj.role) &&
    "created_at" in obj && typeof obj.created_at === "string" &&
    "updated_at" in obj &&
    (typeof obj.updated_at === "string" || obj.updated_at === null) &&
    "avatar_mime" in obj &&
    (typeof obj.avatar_mime === "string" || obj.avatar_mime === null) &&
    "description" in obj &&
    (typeof obj.description === "string" || obj.description === null) &&
    "invited_by" in obj &&
    (typeof obj.invited_by === "string" || obj.invited_by === null) &&
    "email" in obj && typeof obj.email === "string";
}

/** Converts a row to the stored {@link User}. */
export function userRowToApi(row: UserRow): User {
  return {
    id: row.id,
    username: row.username,
    passwordHash: row.password_hash,
    role: row.role,
    createdAt: new Date(row.created_at),
    updatedAt: row.updated_at ? new Date(row.updated_at) : undefined,
    avatarMime: row.avatar_mime ?? undefined,
    description: row.description ?? undefined,
    invitedByUsername: typeof row.invited_by_username === "string"
      ? row.invited_by_username
      : undefined,
    email: row.email,
  };
}

/** Converts a {@link User} back to a row, without the join-only columns. */
export function userApiToRow(user: User): UserRow {
  return {
    id: user.id,
    username: user.username,
    password_hash: user.passwordHash,
    role: user.role,
    created_at: user.createdAt.toISOString(),
    updated_at: user.updatedAt?.toISOString() ?? null,
    avatar_mime: user.avatarMime ?? null,
    description: user.description ?? null,
    invited_by: null,
    invited_by_username: null,
    email: user.email,
  };
}