import { isDefined, isObject } from "prostgles-types";
import { PostgresNotifListenManager } from "../../PostgresNotifListenManager";
import { getWatchSchemaTagList } from "../../SchemaWatch/getWatchSchemaTagList";
import { type PubSubManager } from "../PubSubManager";
import { getPubSubManagerInitQuery } from "./getPubSubManagerInitQuery";
import { asValue, NOTIF_CHANNEL } from "../PubSubManagerUtils";
export const REALTIME_TRIGGER_CHECK_QUERY =
  "prostgles-server internal query used to manage realtime triggers";

export const tout = (ms: number) => new Promise((res) => setTimeout(res, ms));

export async function initPubSubManager(this: PubSubManager): Promise<PubSubManager | undefined> {
  if (!this.getIsDestroyed()) return undefined;

  const initQuery = await getPubSubManagerInitQuery.bind(this.dboBuilder)();

  /**
   * High database activity might cause deadlocks.
   * Must retry
   */
  let didDeadlock = false;
  let tries = 3;
  let error: any;
  while (isDefined(initQuery) && tries > 0) {
    try {
      /** Try to reduce race condition deadlocks due to multiple clients connecting at the same time */
      await tout(Math.random());

      await this.db.tx((t) => t.any(initQuery));
      error = undefined;
      tries = 0;
    } catch (e: any) {
      if (!didDeadlock && isObject(e) && e.code === "40P01") {
        didDeadlock = true;
        tries = 5;
        console.error("Deadlock detected. Retrying...");
      }
      error = e;
      tries--;
    }
  }
  if (error) {
    throw error;
  }

  if (!this.getIsDestroyed()) return;

  /* Prepare App id */
  if (!this.appInfoWasInserted) {
    this.appInfoWasInserted = true;
    const check_frequency_ms = this.appCheckFrequencyMS;
    const watching_schema_tag_names =
      this.dboBuilder.prostgles.schemaWatch?.type.watchType !== "NONE" ?
        getWatchSchemaTagList(this.dboBuilder.prostgles.opts.watchSchema)
      : null;
    await this.db.one(
      "INSERT INTO prostgles.apps (id, check_frequency_ms, watching_schema_tag_names, application_name) \
      VALUES($1, $2, $3, current_setting('application_name')) \
      RETURNING *; ",
      [this.appId, check_frequency_ms, watching_schema_tag_names]
    );

    const appRecord = await this.db.one<{ application_name: string | null }>(
      "SELECT * FROM prostgles.apps WHERE id = $1",
      [this.appId]
    );
    if (!appRecord.application_name?.includes(this.appId)) {
      throw `initPubSubManager error: App record with application_name containing appId (${this.appId}) not found`;
    }

    await this.db.any(`
      DELETE FROM prostgles.app_triggers
      WHERE app_id = ${asValue(this.appId)}
    `);
  }

  this.postgresNotifListenManager = new PostgresNotifListenManager(
    this.db,
    this.notifListener,
    NOTIF_CHANNEL.getFull(this.appId)
  );

  await this.initialiseEventTriggers();

  return this;
}