/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
  ChatStore:
    "moz-src:///browser/components/aiwindow/ui/modules/ChatStore.sys.mjs",
  TelemetryEngine:
    "moz-src:///browser/components/aiwindow/models/TelemetryUtils.sys.mjs",
  submitTelemetryResult:
    "moz-src:///browser/components/aiwindow/models/TelemetryUtils.sys.mjs",
  setInterval: "resource://gre/modules/Timer.sys.mjs",
  clearInterval: "resource://gre/modules/Timer.sys.mjs",
});

ChromeUtils.defineLazyGetter(lazy, "console", function () {
  return console.createInstance({
    prefix: "LLMTelemetry",
    maxLogLevelPref: "browser.smartwindow.telemetryLogLevel",
  });
});

const LAST_RUN_PREF = "browser.smartwindow.lastLLMTelemetryRunTime";
const SCHEDULER_POLL_INTERVAL_MS = 2 * 60 * 1000;
const SCHEDULER_COOLDOWN_MS = 24 * 60 * 60 * 1000;

/**
 * Schedules periodic LLM-based telemetry jobs
 *
 */
export class TelemetryScheduler {
  #intervalHandle = 0;
  #destroyed = false;
  #running = false;

  static #instance = null;

  /**
   * Initializes the scheduler.
   *
   * This should be called from startup/feature initialization code.
   *
   * @returns {TelemetryScheduler}
   *          The scheduler instance.
   */
  static maybeInit() {
    if (!this.#instance) {
      this.#instance = new TelemetryScheduler();
    }

    return this.#instance;
  }

  /**
   * Creates a new scheduler instance.
   *
   * The constructor:
   * - Starts the periodic interval timer.
   */
  constructor() {
    // run immediately (first run) or just start the interval.
    void this.#init();
    lazy.console.debug("Initialized");
  }

  /**
   * initializer for the telemetry scheduler.
   *
   * - Otherwise, starts the periodic interval timer.
   *
   * @private
   * @returns {Promise<void>}
   */
  async #init() {
    const isFirstRun = Services.prefs.getIntPref(LAST_RUN_PREF, 0) === 0;

    if (isFirstRun) {
      lazy.console.debug("First run detected; running immediately.");
      // #onInterval's finally will start the interval
      await this.#onInterval();
    } else {
      this.#startInterval();
    }
  }

  /**
   * Starts the interval that periodically evaluates to check to see
   * if SCHEDULER_COOLDOWN_MS has passed since running end-of-conversation
   * telemetry
   *
   * @throws {Error} If an interval is already running.
   */
  #startInterval() {
    if (this.#intervalHandle) {
      throw new Error(
        "Attempting to start an interval when one already existed"
      );
    }
    this.#intervalHandle = lazy.setInterval(
      this.#onInterval,
      SCHEDULER_POLL_INTERVAL_MS
    );
  }

  /**
   * Stops the currently running interval, if any.
   */
  #stopInterval() {
    if (this.#intervalHandle) {
      lazy.clearInterval(this.#intervalHandle);
      this.#intervalHandle = 0;
    }
  }
  /**
   * Periodic interval handler.
   *
   * @private
   * @returns {Promise<void>} Resolves once the interval run completes.
   */
  #onInterval = async () => {
    if (this.#destroyed) {
      lazy.console.warn("Interval fired after destroy; ignoring.");
      return;
    }

    if (this.#running) {
      lazy.console.debug(
        "Skipping run because a previous run is still in progress."
      );
      return;
    }

    // check to see if the last run was less than SCHEDULER_COOLDOWN_MS - if yes, return
    const lastRun = Services.prefs.getIntPref(LAST_RUN_PREF, 0) * 1000; // back to ms
    if (Date.now() - lastRun < SCHEDULER_COOLDOWN_MS) {
      return;
    }

    this.#running = true;
    this.#stopInterval();
    const intervalStart = ChromeUtils.now();

    try {
      // run telemetry
      const conversationsToRun =
        await lazy.ChatStore.getConversationsForTelemetry();
      lazy.console.debug(
        `LLM-telemetry -- found ${conversationsToRun.length} records`
      );
      const telemetryEngine = new lazy.TelemetryEngine();

      lazy.console.debug("Running LLM-telemetry");
      for (const conversationObj of conversationsToRun) {
        if (this.#destroyed) {
          break;
        }
        try {
          const telemetryNames = Object.keys(conversationObj.telemetryJobs);
          const conversation = await lazy.ChatStore.findConversationById(
            conversationObj.convId
          );
          if (!conversation) {
            continue;
          }
          const results = (
            await telemetryEngine.runTelemetryByName(
              telemetryNames,
              conversation
            )
          ).map(r => ({
            ...r,
            samplingProbability:
              conversationObj.telemetryProbs[r.telemetry_name] ?? 0,
          }));
          lazy.submitTelemetryResult(
            results,
            conversation,
            conversationObj.modelId,
            {
              record_type: "endOfConversation",
              uniform_sampling_probability:
                conversationObj.uniformSamplingProbability ?? 0,
            }
          );
          await lazy.ChatStore.markLLMTelemetryProcessed(
            conversationObj.convId,
            conversationObj.telemetryJobs,
            conversation.currentTurnIndex()
          );
        } catch (error) {
          lazy.console.error(
            `Failed to generate llm telemetry for conversation ${conversationObj.convId}`,
            error
          );
        }
      }
    } catch (error) {
      lazy.console.error("Failed to generate llm telemetry records", error);
    } finally {
      ChromeUtils.addProfilerMarker(
        "SmartWindow",
        { startTime: intervalStart },
        "LLMaJTelemetryManager"
      );
      Services.prefs.setIntPref(LAST_RUN_PREF, Math.floor(Date.now() / 1000));
      if (!this.#destroyed) {
        this.#startInterval();
      }
      this.#running = false;
    }
  };

  destroy() {
    this.#stopInterval();
    this.#destroyed = true;
    TelemetryScheduler.#instance = null;
    lazy.console.debug("Destroyed");
  }
}