import "server-only";
import http from "node:http";
import https from "node:https";
import { Cam, type CamProfile } from "onvif";
import { getDigestHeaders } from "onvif/lib/utils";
import { getCredentials, type Credentials } from "./credential-store";

export interface CameraProfile {
  token: string;
  name?: string;
  encoding?: string;
  width?: number;
  height?: number;
  fps?: number;
}

export interface CameraInfo {
  manufacturer?: string;
  model?: string;
  firmwareVersion?: string;
  serialNumber?: string;
  profiles: CameraProfile[];
}

export interface Snapshot {
  contentType: string;
  body: Buffer;
}

const REQUEST_TIMEOUT_MS = 10_000;

/** A camera in the registry: stable ID plus its last known address. */
export interface CameraTarget {
  id: string;
  host: string;
  port: number;
}

/** The camera rejected (or was never given) a username/password. */
export class CameraAuthError extends Error {
  name = "CameraAuthError";
  constructor(
    message: string,
    /** True when no login was saved at all, as opposed to the camera rejecting one. */
    readonly missingLogin = false,
  ) {
    super(message);
  }
}

/**
 * The camera hasn't been activated (first admin password never set). Vendors such as
 * Hikvision refuse every ONVIF request, even unauthenticated ones, until then.
 */
export class CameraInactiveError extends Error {
  name = "CameraInactiveError";
}

const INACTIVE_RESPONSE = /device is inactive|not activated|inactive device/i;

const AUTH_FAILURE = /\b401\b|not ?authori[sz]ed|authenticat|unauthori[sz]ed/i;

function asAuthError(err: unknown): unknown {
  const message = err instanceof Error ? err.message : String(err);
  return AUTH_FAILURE.test(message) ? new CameraAuthError(message) : err;
}

/**
 * Only RFC 1918 IPv4 addresses may be targeted, so the snapshot/info routes can't be
 * used to make this server request arbitrary hosts.
 */
export function isAllowedHost(host: string): boolean {
  const m = host.match(/^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/);
  if (!m) return false;
  const [a, b, c, d] = m.slice(1).map(Number);
  if ([a, b, c, d].some((n) => n > 255)) return false;
  return a === 10 || (a === 172 && b >= 16 && b <= 31) || (a === 192 && b === 168);
}

// Connected Cam instances are reused across requests; connect() makes several SOAP
// calls, which is too slow to repeat for every snapshot.
const cams = new Map<string, Promise<Cam>>();
const snapshotUris = new Map<string, Promise<string>>();

/**
 * Connects and loads profiles. Rejects with CameraInactiveError for unactivated cameras
 * and CameraAuthError if there is no login or it is refused. With no credentials it still
 * contacts the camera (GetSystemDateAndTime needs no login) to tell those two apart.
 */
function openCam(host: string, port: number, creds: Credentials | null): Promise<Cam> {
  return new Promise<Cam>((resolve, reject) => {
    const cam = new Cam({
      hostname: host,
      port,
      ...(creds ?? {}),
      timeout: REQUEST_TIMEOUT_MS,
      // Use the discovered address even if the camera advertises another one.
      preserveAddress: true,
      autoconnect: false,
    });
    let inactive = false;
    cam.on("rawResponse", (body: string) => {
      if (INACTIVE_RESPONSE.test(body)) inactive = true;
    });
    // If GetProfiles fails (typically bad credentials), connect() still succeeds but
    // only emits a "warning" and leaves profiles empty; surface that as an error.
    let warning: string | undefined;
    cam.on("warning", (w: unknown) => (warning = String(w)));
    cam.connect((err) => {
      if (inactive) {
        return reject(new CameraInactiveError("Camera has not been activated yet"));
      }
      if (err) return reject(asAuthError(err));
      if (!cam.profiles?.length) {
        if (!creds) return reject(new CameraAuthError("No login saved for this camera", true));
        return reject(
          asAuthError(new Error(`Camera returned no media profiles${warning ? `: ${warning}` : ""}`)),
        );
      }
      resolve(cam);
    });
  });
}

/** The cached, logged-in connection for a camera (shared with camera-settings.ts). */
export function connect(target: CameraTarget): Promise<Cam> {
  const key = `${target.host}:${target.port}`;
  let pending = cams.get(key);
  if (!pending) {
    pending = getCredentials(target.id).then((creds) => openCam(target.host, target.port, creds));
    pending.catch(() => cams.delete(key));
    cams.set(key, pending);
  }
  return pending;
}

/** Verifies a login against the camera without touching cached connections. */
export async function testCredentials(target: CameraTarget, creds: Credentials) {
  await openCam(target.host, target.port, creds);
}

/** Drops cached connections so the next request logs in again. */
export function resetConnection({ host, port }: CameraTarget) {
  const prefix = `${host}:${port}`;
  cams.delete(prefix);
  for (const key of snapshotUris.keys()) {
    if (key.startsWith(`${prefix}/`)) snapshotUris.delete(key);
  }
}

/** A profile's video encoder: Media1 uses videoEncoderConfiguration, Media2 configurations.videoEncoder. */
export function encoderConfig(p: CamProfile) {
  return p.videoEncoderConfiguration ?? p.configurations?.videoEncoder;
}

/** A profile's token: an element in Media1, an attribute in Media2. */
export function profileToken(p: CamProfile): string {
  return p.token ?? p.$?.token;
}

function toProfile(p: CamProfile): CameraProfile {
  const enc = encoderConfig(p);
  const resolution = enc?.resolution;
  return {
    token: profileToken(p),
    name: p.name,
    encoding: enc?.encoding,
    width: resolution?.width,
    height: resolution?.height,
    fps: enc?.rateControl?.frameRateLimit ?? enc?.rateControl?.$?.FrameRateLimit,
  };
}

export async function getCameraInfo(target: CameraTarget): Promise<CameraInfo> {
  const cam = await connect(target);
  const device = await new Promise<Record<string, string>>((resolve, reject) =>
    cam.getDeviceInformation((err, info) => (err ? reject(err) : resolve(info ?? {}))),
  ).catch(() => ({}) as Record<string, string>);

  return {
    manufacturer: device.manufacturer,
    model: device.model,
    firmwareVersion: device.firmwareVersion,
    serialNumber: device.serialNumber,
    profiles: (cam.profiles ?? []).map(toProfile),
  };
}

function snapshotUri(target: CameraTarget, profileToken?: string): Promise<string> {
  const key = `${target.host}:${target.port}/${profileToken ?? ""}`;
  let pending = snapshotUris.get(key);
  if (!pending) {
    pending = connect(target).then(
      (cam) =>
        new Promise<string>((resolve, reject) =>
          cam.getSnapshotUri(profileToken ? { profileToken } : {}, (err, res) =>
            err || !res?.uri
              ? reject(err ?? new Error("Camera returned no snapshot URI"))
              : resolve(res.uri),
          ),
        ),
    );
    pending.catch(() => snapshotUris.delete(key));
    snapshotUris.set(key, pending);
  }
  return pending;
}

interface HttpResult {
  status: number;
  headers: http.IncomingHttpHeaders;
  rawHeaders: string[];
  body: Buffer;
}

function httpGet(url: URL, authorization?: string): Promise<HttpResult> {
  const lib = url.protocol === "https:" ? https : http;
  return new Promise((resolve, reject) => {
    const req = lib.request(
      url,
      {
        method: "GET",
        headers: authorization ? { Authorization: authorization } : {},
        // Cameras commonly use self-signed certificates.
        rejectUnauthorized: false,
        timeout: REQUEST_TIMEOUT_MS,
      },
      (res) => {
        const chunks: Buffer[] = [];
        res.on("data", (c: Buffer) => chunks.push(c));
        res.on("end", () =>
          resolve({
            status: res.statusCode ?? 0,
            headers: res.headers,
            rawHeaders: res.rawHeaders,
            body: Buffer.concat(chunks),
          }),
        );
        res.on("error", reject);
      },
    );
    req.on("timeout", () => req.destroy(new Error("Snapshot request timed out")));
    req.on("error", reject);
    req.end();
  });
}

/**
 * Fetches a JPEG from the camera's snapshot URI, answering a Digest or Basic
 * challenge with the ONVIF credentials.
 */
export async function getSnapshot(target: CameraTarget, profileToken?: string): Promise<Snapshot> {
  const { host } = target;
  let uri: string;
  try {
    uri = await snapshotUri(target, profileToken);
  } catch (err) {
    resetConnection(target);
    throw err;
  }

  const url = new URL(uri);
  // Some cameras advertise an unreachable or internal hostname in the snapshot URI.
  url.hostname = host;
  let res = await httpGet(url);

  if (res.status === 401) {
    const cam = await connect(target);
    const { username, password } = (await getCredentials(target.id)) ?? {
      username: "",
      password: "",
    };
    const digest = getDigestHeaders(res.rawHeaders);
    const authorization = digest.length
      ? cam.digestAuth(digest, { method: "GET", path: url.pathname + url.search })
      : `Basic ${Buffer.from(`${username}:${password}`).toString("base64")}`;
    res = await httpGet(url, authorization);
  }

  if (res.status === 401) {
    resetConnection(target);
    throw new CameraAuthError("Snapshot login rejected (HTTP 401)");
  }
  if (res.status !== 200) {
    throw new Error(`Snapshot request failed with HTTP ${res.status}`);
  }
  return {
    contentType: String(res.headers["content-type"] ?? "image/jpeg"),
    body: res.body,
  };
}

/**
 * The camera's RTSP address for its main (first) or sub (second) stream, with the stored
 * login embedded, for the local video bridge only (vrek iss-nk6zrzv). Contains the camera
 * password: never return it to a client or log it.
 */
export async function rtspSourceWithLogin(target: CameraTarget, stream: "main" | "sub"): Promise<string> {
  const cam = await connect(target);
  const profile = (cam.profiles ?? [])[stream === "main" ? 0 : 1];
  if (!profile) throw new Error(`Camera has no ${stream} stream`);
  const uri = await new Promise<string>((resolve, reject) =>
    cam.getStreamUri({ protocol: "RTSP", profileToken: profileToken(profile) }, (err, res) =>
      err || !res?.uri ? reject(err ?? new Error("Camera returned no stream URI")) : resolve(res.uri),
    ),
  );
  const url = new URL(uri);
  // Some cameras advertise an unreachable or internal hostname in the stream URI.
  url.hostname = target.host;
  const creds = await getCredentials(target.id);
  if (creds) {
    url.username = encodeURIComponent(creds.username);
    url.password = encodeURIComponent(creds.password);
  }
  return url.toString();
}

/** The camera's own name and location, as discovery sees them (vrek iss-h1qwke5). */
export interface CameraScopes {
  name?: string;
  location?: string;
}

const SCOPE_PREFIX = "onvif://www.onvif.org/";
const scopeUri = (key: string, value: string) => `${SCOPE_PREFIX}${key}/${encodeURIComponent(value)}`;

function scopeValue(uris: string[], key: string): string | undefined {
  const prefix = `${SCOPE_PREFIX}${key}/`;
  const match = uris.find((uri) => uri.startsWith(prefix));
  return match ? decodeURIComponent(match.slice(prefix.length)) : undefined;
}

/** A scope as the library reports it: Media1 nests the parts, Media2 uses attributes. */
type Scope = { ScopeDef?: string; ScopeItem?: string; scopeDef?: string; scopeItem?: string };

const asUri = (scope: Scope) => scope.ScopeItem ?? scope.scopeItem ?? "";
const isConfigurable = (scope: Scope) =>
  (scope.ScopeDef ?? scope.scopeDef ?? "").toLowerCase() === "configurable";

function readScopes(cam: Cam): Promise<Scope[]> {
  return new Promise((resolve, reject) =>
    (cam as unknown as { getScopes(cb: (err: Error | null, scopes?: Scope[]) => void): void }).getScopes(
      (err, scopes) => (err ? reject(err) : resolve(scopes ?? [])),
    ),
  );
}

export async function getCameraScopes(target: CameraTarget): Promise<CameraScopes> {
  const scopes = await readScopes(await connect(target));
  const uris = scopes.map(asUri);
  return { name: scopeValue(uris, "name"), location: scopeValue(uris, "location") };
}

/**
 * Renames the camera itself. SetScopes replaces every configurable scope, so the others
 * are read first and sent back untouched; fixed scopes are the camera's own and are left
 * out. Returns what the camera reports afterwards, which is what actually applied.
 */
export async function setCameraScopes(target: CameraTarget, patch: CameraScopes): Promise<CameraScopes> {
  const cam = await connect(target);
  const existing = await readScopes(cam);
  const keep = existing
    .filter(isConfigurable)
    .map(asUri)
    .filter((uri) => uri && !uri.startsWith(`${SCOPE_PREFIX}name/`) && !uri.startsWith(`${SCOPE_PREFIX}location/`));

  const wanted = [...keep];
  const current = await getCameraScopes(target);
  const name = patch.name ?? current.name;
  const location = patch.location ?? current.location;
  if (name) wanted.push(scopeUri("name", name));
  if (location) wanted.push(scopeUri("location", location));

  await new Promise<void>((resolve, reject) =>
    (cam as unknown as { setScopes(uris: string[], cb: (err: Error | null) => void): void }).setScopes(
      wanted,
      (err) => (err ? reject(err) : resolve()),
    ),
  );
  return getCameraScopes(target);
}