// The UniFi controller API client — unifi's own code, living in the module (novox/hq ADR 0039).
// Moved out of the shared hal sdk, where a change to the UniFi API rebuilt everything; here it
// rebuilds only unifi. This module's tools import it, and nothing outside unifi does.
//
// The controller speaks its classic self-managed API (/api/login, /api/s/<site>/...), authenticated
// with a username and password and a session cookie. It presents a self-signed certificate, so the
// requests deliberately skip TLS verification — see uniFetch below.

import { readFileSync } from "node:fs";
import { request as httpsRequest } from "node:https";

export interface UnifiPortForward {
  _id?: string;
  name: string;
  enabled: boolean;
  pfwd_interface: string;
  src: string;
  dst_port: string;
  fwd: string;
  fwd_port: string;
  proto: string;
  log: boolean;
  site_id?: string;
}

export interface UnifiDevice {
  _id: string;
  name: string;
  model: string;
  type: string;
  ip: string;
  mac: string;
  version: string;
  adopted: boolean;
  state: number;
  uptime: number;
}

export interface UnifiClientDevice {
  _id: string;
  name?: string;
  hostname?: string;
  ip: string;
  mac: string;
  oui: string;
  is_wired: boolean;
  network?: string;
  last_seen: number;
  uptime?: number;
}

interface UnifiResponse<T> {
  meta: { rc: string; msg?: string };
  data: T[];
}

/** The minimal response shape uniFetch returns — enough for this client, without pretending to be
 *  the whole DOM `Response`. */
interface UniReply {
  ok: boolean;
  status: number;
  statusText: string;
  setCookies: string[];
  text: () => Promise<string>;
  json: () => Promise<unknown>;
}

interface UniInit {
  method?: string;
  headers?: Record<string, string>;
  body?: string;
}

/**
 * Fetch wrapper that disables TLS verification for UniFi's self-signed certificate. Uses node:https
 * directly rather than the built-in fetch, because fetch caches NODE_TLS_REJECT_UNAUTHORIZED at
 * startup and scoped per-request toggling does not work — the reason the hal original reached for
 * https as well.
 */
function uniFetch(url: string, init?: UniInit): Promise<UniReply> {
  const parsed = new URL(url);
  return new Promise((resolve, reject) => {
    const req = httpsRequest(
      parsed,
      {
        method: init?.method ?? "GET",
        headers: init?.headers ?? {},
        rejectUnauthorized: false,
      },
      (res) => {
        const chunks: Buffer[] = [];
        res.on("data", (chunk: Buffer) => chunks.push(chunk));
        res.on("end", () => {
          const body = Buffer.concat(chunks).toString();
          const status = res.statusCode ?? 0;
          const rawCookies = res.headers["set-cookie"];
          const setCookies = Array.isArray(rawCookies) ? rawCookies : rawCookies ? [rawCookies] : [];
          resolve({
            ok: status >= 200 && status < 300,
            status,
            statusText: res.statusMessage ?? "",
            setCookies,
            text: async () => body,
            json: async () => JSON.parse(body) as unknown,
          });
        });
      },
    );
    req.on("error", reject);
    if (init?.body) req.write(init.body);
    req.end();
  });
}

/** The settings-merged config the mesh delivers (novox/hq ADR 0046): { url, username, password,
 *  site }. Read from MESH_UNIFI_CONFIG_FILE; absent or unreadable is an empty config, not a throw. */
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 UnifiApiClient {
  readonly baseUrl: string;
  private cookie: string | null = null;
  private csrfToken: string | null = null;

  constructor(
    url: string,
    private readonly username: string,
    private readonly password: string,
    private readonly site: string = "default",
  ) {
    this.baseUrl = url.replace(/\/+$/, "");
  }

  /**
   * Build from the module's resolved environment. URL, credentials and site come from the
   * settings-merged config file, falling back to MESH_UNIFI_* env vars and finally the local
   * controller port. Throws when no username/password is configured, so a misconfigured module
   * exposes nothing rather than calling the controller unauthenticated.
   */
  static fromEnv(env: NodeJS.ProcessEnv = process.env): UnifiApiClient {
    const cfg = meshConfig(env.MESH_UNIFI_CONFIG_FILE);
    const url = cfg.url ?? env.MESH_UNIFI_URL ?? `https://127.0.0.1:${env.UNIFI_HTTPS_PORT ?? "8443"}`;
    const username = cfg.username ?? env.MESH_UNIFI_USERNAME;
    const password = cfg.password ?? env.MESH_UNIFI_PASSWORD;
    const site = cfg.site ?? env.MESH_UNIFI_SITE ?? "default";
    if (!username || !password) {
      throw new Error("no UniFi credentials — set MESH_UNIFI_USERNAME and MESH_UNIFI_PASSWORD");
    }
    return new UnifiApiClient(url, username, password, site);
  }

  private async login(): Promise<void> {
    const res = await uniFetch(`${this.baseUrl}/api/login`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ username: this.username, password: this.password }),
    });
    if (!res.ok && res.status !== 302) {
      throw new Error(`UniFi auth failed: ${res.status} ${await res.text()}`);
    }
    // Extract the session cookie and CSRF token from the response.
    const cookies: string[] = [];
    for (const c of res.setCookies) {
      const name = c.split("=")[0];
      const value = c.split(";")[0];
      if (name === "TOKEN" || name === "unifises" || name === "csrf_token") {
        cookies.push(value);
      }
      if (name === "csrf_token") {
        this.csrfToken = value.split("=")[1];
      }
    }
    this.cookie = cookies.join("; ");
    if (!this.cookie) {
      throw new Error("UniFi auth: no session cookie returned");
    }
  }

  private async request<T>(method: string, path: string, body?: unknown): Promise<T[]> {
    if (!this.cookie) await this.login();

    const doRequest = async (): Promise<UniReply> => {
      const headers: Record<string, string> = {
        "Content-Type": "application/json",
        Cookie: this.cookie!,
      };
      if (this.csrfToken) headers["X-Csrf-Token"] = this.csrfToken;
      return uniFetch(`${this.baseUrl}${path}`, {
        method,
        headers,
        ...(body ? { body: JSON.stringify(body) } : {}),
      });
    };

    let res = await doRequest();

    if (res.status === 401) {
      this.cookie = null;
      await this.login();
      res = await doRequest();
    }

    if (!res.ok) throw new Error(`UniFi ${method} ${path}: ${res.status} ${await res.text()}`);
    const data = (await res.json()) as UnifiResponse<T>;
    if (data.meta.rc !== "ok") throw new Error(`UniFi API error: ${data.meta.msg}`);
    return data.data;
  }

  // --- Port forwarding ---

  async listPortForwards(): Promise<UnifiPortForward[]> {
    return this.request<UnifiPortForward>("GET", `/api/s/${this.site}/rest/portforward`);
  }

  async createPortForward(rule: Omit<UnifiPortForward, "_id" | "site_id">): Promise<UnifiPortForward> {
    const result = await this.request<UnifiPortForward>("POST", `/api/s/${this.site}/rest/portforward`, rule);
    return result[0];
  }

  async updatePortForward(id: string, rule: Partial<UnifiPortForward>): Promise<UnifiPortForward> {
    const result = await this.request<UnifiPortForward>("PUT", `/api/s/${this.site}/rest/portforward/${id}`, rule);
    return result[0];
  }

  async deletePortForward(id: string): Promise<void> {
    await this.request<unknown>("DELETE", `/api/s/${this.site}/rest/portforward/${id}`);
  }

  // --- Devices ---

  async listDevices(): Promise<UnifiDevice[]> {
    return this.request<UnifiDevice>("GET", `/api/s/${this.site}/stat/device`);
  }

  // --- Clients ---

  async listClients(): Promise<UnifiClientDevice[]> {
    return this.request<UnifiClientDevice>("GET", `/api/s/${this.site}/stat/sta`);
  }

  /**
   * A health probe that never throws: report whether the controller answers and can be logged into.
   * Every other call assumes the controller is up and authenticated; this is the one that tells the
   * mesh whether it is, so a diagnosis does not start from a stack trace.
   */
  async reachable(): Promise<{ reachable: boolean; url: string; error?: string }> {
    try {
      await this.listDevices();
      return { reachable: true, url: this.baseUrl };
    } catch (err) {
      return { reachable: false, url: this.baseUrl, error: err instanceof Error ? err.message : String(err) };
    }
  }
}