import { randomUUID } from 'node:crypto';
import { app } from 'electron';
import axios from 'axios';
import logManager from '@electron/service/logger';
import configManager from '@electron/service/config-service';

const POSTHOG_API_KEY = 'phc_aGNegeJQP5FzNiF2rEoKqQbkuCpiiETMttplibXpB0n';
const POSTHOG_HOST = 'https://us.i.posthog.com';
const TELEMETRY_REQUEST_TIMEOUT_MS = 2_500;
const TELEMETRY_SHUTDOWN_TIMEOUT_MS = 1_500;

let telemetryEnabled = false;
let distinctId = '';
const pendingCaptures = new Set<Promise<void>>();

function getCommonProperties(): Record<string, unknown> {
  return {
    $app_version: app.getVersion(),
    $os: process.platform,
    os_tag: process.platform,
    arch: process.arch,
  };
}

function queueCapture(event: string, properties: Record<string, unknown>): void {
  let capturePromise: Promise<void>;
  const request = axios.post(
    `${POSTHOG_HOST}/capture/`,
    {
      api_key: POSTHOG_API_KEY,
      event,
      properties: {
        distinct_id: distinctId,
        ...properties,
      },
    },
    {
      headers: {
        'Content-Type': 'application/json',
      },
      timeout: TELEMETRY_REQUEST_TIMEOUT_MS,
      validateStatus: () => true,
    },
  ).then((response) => {
    if (response.status >= 400) {
      logManager.debug(`Telemetry backend rejected event "${event}" with status ${response.status}`);
    }
  }).catch((error) => {
    logManager.debug(`Failed to capture telemetry event "${event}":`, error);
  }).finally(() => {
    pendingCaptures.delete(capturePromise);
  });

  capturePromise = request.then(() => {});
  pendingCaptures.add(capturePromise);
}

export async function initTelemetry(): Promise<void> {
  telemetryEnabled = Boolean(configManager.get('telemetryEnabled' as never));
  if (!telemetryEnabled) {
    logManager.info('Telemetry is disabled; observability stays local-only');
    return;
  }

  const storedDistinctId = configManager.get<string | null>('machineId' as never);
  distinctId = storedDistinctId && storedDistinctId.trim()
    ? storedDistinctId
    : randomUUID();
  if (!storedDistinctId) {
    configManager.set('machineId' as never, distinctId);
  }

  const hasReportedInstall = Boolean(configManager.get('hasReportedInstall' as never));
  if (!hasReportedInstall) {
    captureTelemetryEvent('app_installed');
    configManager.set('hasReportedInstall' as never, true);
  }
  captureTelemetryEvent('app_opened');
}

export function trackMetric(event: string, properties: Record<string, unknown> = {}): void {
  logManager.info(`[metric] ${event}`, properties);
}

export function captureTelemetryEvent(
  event: string,
  properties: Record<string, unknown> = {},
): void {
  if (!telemetryEnabled || !distinctId) {
    return;
  }

  const mergedProperties = {
    ...getCommonProperties(),
    ...properties,
  };
  queueCapture(event, mergedProperties);
}

export async function shutdownTelemetry(): Promise<void> {
  telemetryEnabled = false;
  if (pendingCaptures.size === 0) {
    distinctId = '';
    return;
  }

  const captures = Array.from(pendingCaptures);
  await Promise.race([
    Promise.allSettled(captures).then(() => undefined),
    new Promise<void>((resolve) => {
      setTimeout(resolve, TELEMETRY_SHUTDOWN_TIMEOUT_MS);
    }),
  ]);

  distinctId = '';
}