// The Keycloak admin API client — keycloak's own code, living in the module (novox/hq ADR 0039).
// Moved out of the shared hal sdk, where a change to Keycloak's admin API rebuilt everything; here
// it rebuilds only keycloak. Both this module's tools and its events entrypoint import it, and
// nothing outside keycloak does.

import { readFileSync } from "node:fs";

/** The settings-merged config the mesh delivers (novox/hq ADR 0046): { url, apiKey, token, password, user, ... }. */
function meshConfig(file?: string): Record<string, string> {
  if (!file) return {};
  try { return JSON.parse(readFileSync(file, "utf8")) as Record<string, string>; }
  catch { return {}; }
}

export class KeycloakClient {
  readonly baseUrl: string;
  readonly defaultRealm: string;
  // The admin token is short-lived; caching it (minus a safety margin) spares every call a fresh
  // password grant, and a 401 mid-flight refreshes it once rather than failing the request.
  private tokenCache: { token: string; expiresAt: number } | null = null;

  constructor(
    url: string,
    private readonly adminUser: string,
    private readonly adminPass: string,
    defaultRealm = "master",
  ) {
    this.baseUrl = url.replace(/\/+$/, "");
    this.defaultRealm = defaultRealm;
  }

  /**
   * Build from the module's resolved environment. Admin URL, credentials and the fallback realm are
   * read from MESH_KEYCLOAK_* — the names the mesh sets — falling back to the container's own
   * KEYCLOAK_ADMIN/KEYCLOAK_ADMIN_PASSWORD so a co-located server needs nothing configured twice.
   * Throws when no admin password can be found: without it the client can do nothing, so failing
   * here lets the tool runtime expose no keycloak tools rather than tools that always error.
   */
  static fromEnv(env: NodeJS.ProcessEnv = process.env): KeycloakClient {
    const cfg = meshConfig(env.MESH_KEYCLOAK_CONFIG_FILE);
    const url = cfg.url ?? env.MESH_KEYCLOAK_URL ?? `http://127.0.0.1:${env.KEYCLOAK_PORT ?? "8080"}`;
    const adminUser = cfg.user ?? env.MESH_KEYCLOAK_ADMIN ?? env.KEYCLOAK_ADMIN ?? "admin";
    const adminPass = cfg.password ?? env.MESH_KEYCLOAK_PASSWORD ?? env.KEYCLOAK_ADMIN_PASSWORD;
    if (!adminPass) throw new Error("no Keycloak admin password — set MESH_KEYCLOAK_PASSWORD");
    const realm = cfg.realm ?? env.MESH_KEYCLOAK_REALM ?? "master";
    return new KeycloakClient(url, adminUser, adminPass, realm);
  }

  private async getToken(): Promise<string> {
    if (this.tokenCache && Date.now() < this.tokenCache.expiresAt) return this.tokenCache.token;

    const res = await fetch(`${this.baseUrl}/realms/master/protocol/openid-connect/token`, {
      method: "POST",
      headers: { "Content-Type": "application/x-www-form-urlencoded" },
      body: new URLSearchParams({
        grant_type: "password",
        client_id: "admin-cli",
        username: this.adminUser,
        password: this.adminPass,
      }),
    });
    if (!res.ok) throw new Error(`Keycloak token request failed: ${res.status} ${await res.text()}`);

    const data = (await res.json()) as { access_token: string; expires_in: number };
    this.tokenCache = { token: data.access_token, expiresAt: Date.now() + (data.expires_in - 30) * 1000 };
    return data.access_token;
  }

  private async request<T = unknown>(path: string, options: RequestInit = {}): Promise<T> {
    const doRequest = async (token: string): Promise<Response> =>
      fetch(`${this.baseUrl}/admin/realms${path}`, {
        ...options,
        headers: {
          "Content-Type": "application/json",
          Authorization: `Bearer ${token}`,
          ...(options.headers as Record<string, string>),
        },
      });

    let res = await doRequest(await this.getToken());
    // A cached token that expired against the server's clock reads as 401; drop it and retry once.
    if (res.status === 401) {
      this.tokenCache = null;
      res = await doRequest(await this.getToken());
    }
    if (!res.ok) throw new Error(`Keycloak API error ${res.status}: ${await res.text()}`);
    // 201/204 carry no body — the admin API's create/update/delete answer with an empty response.
    if (res.status === 201 || res.status === 204) return null as T;
    return res.json() as Promise<T>;
  }

  // Realms
  async listRealms(): Promise<Array<{ id: string; realm: string; displayName?: string; enabled: boolean }>> {
    return this.request("/");
  }

  // Users
  async listUsers(realm: string, params: { search?: string; max?: number } = {}): Promise<unknown[]> {
    const qs = new URLSearchParams();
    if (params.search) qs.set("search", params.search);
    if (params.max) qs.set("max", String(params.max));
    const query = qs.toString();
    return this.request(`/${realm}/users${query ? `?${query}` : ""}`);
  }

  async createUser(realm: string, data: {
    username: string;
    email?: string;
    enabled?: boolean;
    credentials?: Array<{ type: string; value: string; temporary: boolean }>;
  }): Promise<void> {
    await this.request(`/${realm}/users`, { method: "POST", body: JSON.stringify({ enabled: true, ...data }) });
  }

  async updateUser(realm: string, userId: string, data: Record<string, unknown>): Promise<void> {
    await this.request(`/${realm}/users/${userId}`, { method: "PUT", body: JSON.stringify(data) });
  }

  async deleteUser(realm: string, userId: string): Promise<void> {
    await this.request(`/${realm}/users/${userId}`, { method: "DELETE" });
  }

  async resetPassword(realm: string, userId: string, password: string, temporary = false): Promise<void> {
    await this.request(`/${realm}/users/${userId}/reset-password`, {
      method: "PUT",
      body: JSON.stringify({ type: "password", value: password, temporary }),
    });
  }

  async getUserSessions(realm: string, userId: string): Promise<unknown[]> {
    return this.request(`/${realm}/users/${userId}/sessions`);
  }

  // Clients
  async listClients(realm: string): Promise<unknown[]> {
    return this.request(`/${realm}/clients`);
  }

  async createClient(realm: string, data: {
    clientId: string;
    name?: string;
    rootUrl?: string;
    redirectUris?: string[];
    publicClient?: boolean;
    protocol?: string;
  }): Promise<void> {
    await this.request(`/${realm}/clients`, {
      method: "POST",
      body: JSON.stringify({ protocol: "openid-connect", enabled: true, ...data }),
    });
  }

  // The admin API addresses a client by its internal UUID, not the human clientId a caller knows;
  // every client-scoped call resolves the one to the other first.
  private async resolveClientId(realm: string, clientId: string): Promise<string> {
    const clients = (await this.listClients(realm)) as Array<Record<string, unknown>>;
    const client = clients.find((c) => c.clientId === clientId);
    if (!client) throw new Error(`Client '${clientId}' not found in realm '${realm}'`);
    return client.id as string;
  }

  async deleteClient(realm: string, clientId: string): Promise<void> {
    await this.request(`/${realm}/clients/${await this.resolveClientId(realm, clientId)}`, { method: "DELETE" });
  }

  async getClientSecret(realm: string, clientId: string): Promise<string> {
    const id = await this.resolveClientId(realm, clientId);
    const result = await this.request<{ value: string }>(`/${realm}/clients/${id}/client-secret`);
    return result.value;
  }

  async addProtocolMapper(realm: string, clientId: string, mapper: {
    name: string;
    protocolMapper: string;
    config: Record<string, string>;
  }): Promise<void> {
    const id = await this.resolveClientId(realm, clientId);
    await this.request(`/${realm}/clients/${id}/protocol-mappers/models`, {
      method: "POST",
      body: JSON.stringify({ protocol: "openid-connect", ...mapper }),
    });
  }

  // Roles
  async listRealmRoles(realm: string): Promise<Array<{ id: string; name: string; description?: string; composite: boolean }>> {
    return this.request(`/${realm}/roles`);
  }

  async createRealmRole(realm: string, data: { name: string; description?: string }): Promise<void> {
    await this.request(`/${realm}/roles`, { method: "POST", body: JSON.stringify(data) });
  }

  async getUserRealmRoles(realm: string, userId: string): Promise<Array<{ id: string; name: string; description?: string }>> {
    return this.request(`/${realm}/users/${userId}/role-mappings/realm`);
  }

  async getAvailableRealmRoles(realm: string, userId: string): Promise<Array<{ id: string; name: string; description?: string }>> {
    return this.request(`/${realm}/users/${userId}/role-mappings/realm/available`);
  }

  async assignRealmRoles(realm: string, userId: string, roles: Array<{ id: string; name: string }>): Promise<void> {
    await this.request(`/${realm}/users/${userId}/role-mappings/realm`, { method: "POST", body: JSON.stringify(roles) });
  }

  async removeRealmRoles(realm: string, userId: string, roles: Array<{ id: string; name: string }>): Promise<void> {
    await this.request(`/${realm}/users/${userId}/role-mappings/realm`, { method: "DELETE", body: JSON.stringify(roles) });
  }

  // Groups
  async listGroups(realm: string): Promise<Array<{ id: string; name: string; path: string; subGroupCount?: number }>> {
    return this.request(`/${realm}/groups`);
  }

  async createGroup(realm: string, name: string): Promise<void> {
    await this.request(`/${realm}/groups`, { method: "POST", body: JSON.stringify({ name }) });
  }

  async getUserGroups(realm: string, userId: string): Promise<Array<{ id: string; name: string; path: string }>> {
    return this.request(`/${realm}/users/${userId}/groups`);
  }

  async addUserToGroup(realm: string, userId: string, groupId: string): Promise<void> {
    await this.request(`/${realm}/users/${userId}/groups/${groupId}`, { method: "PUT" });
  }

  async removeUserFromGroup(realm: string, userId: string, groupId: string): Promise<void> {
    await this.request(`/${realm}/users/${userId}/groups/${groupId}`, { method: "DELETE" });
  }
}