/**
 * Audio navigation store for tracking episode order and position
 * Persists the current episode context (source type, index, and podcastId)
 */

import { createSignal } from "solid-js";
import {
  loadAudioNavFromFile,
  saveAudioNavToFile,
} from "../utils/app-persistence";

/** Source type for audio navigation */
export enum AudioSource {
  FEED = "feed",
  MY_SHOWS = "my_shows",
  SEARCH = "search",
}

/** Audio navigation state */
export interface AudioNavState {
  /** Current source type */
  source: AudioSource;
  /** Index of current episode in the ordered list */
  currentIndex: number;
  /** Podcast ID for My Shows source */
  podcastId?: string;
  /** Timestamp when navigation state was last saved */
  lastUpdated: Date;
}

/** Default navigation state */
const defaultNavState: AudioNavState = {
  source: AudioSource.FEED,
  currentIndex: 0,
  lastUpdated: new Date(),
};

/** Create audio navigation store */
export function createAudioNavStore() {
  const [navState, setNavState] = createSignal<AudioNavState>(defaultNavState);

  /** Persist current navigation state to file (fire-and-forget) */
  function persist(): void {
    saveAudioNavToFile(navState()).catch(() => {});
  }

  /** Load navigation state from file */
  async function init(): Promise<void> {
    const loaded = await loadAudioNavFromFile<AudioNavState>();
    if (loaded) {
      setNavState(loaded);
    }
  }

  /** Fire-and-forget initialization */
  init();

  return {
    /** Get current navigation state */
    get state(): AudioNavState {
      return navState();
    },

    /** Update source type */
    setSource: (source: AudioSource, podcastId?: string) => {
      setNavState((prev) => ({
        ...prev,
        source,
        podcastId,
        lastUpdated: new Date(),
      }));
      persist();
    },

    /** Move to next episode */
    next: (currentIndex: number) => {
      setNavState((prev) => ({
        ...prev,
        currentIndex,
        lastUpdated: new Date(),
      }));
      persist();
    },

    /** Move to previous episode */
    prev: (currentIndex: number) => {
      setNavState((prev) => ({
        ...prev,
        currentIndex,
        lastUpdated: new Date(),
      }));
      persist();
    },

    /** Reset to default state */
    reset: () => {
      setNavState(defaultNavState);
      persist();
    },

    /** Get current index */
    getCurrentIndex: (): number => {
      return navState().currentIndex;
    },

    /** Get current source */
    getSource: (): AudioSource => {
      return navState().source;
    },

    /** Get current podcast ID */
    getPodcastId: (): string | undefined => {
      return navState().podcastId;
    },
  };
}

/** Singleton instance */
let audioNavInstance: ReturnType<typeof createAudioNavStore> | null = null;

export function useAudioNavStore() {
  if (!audioNavInstance) {
    audioNavInstance = createAudioNavStore();
  }
  return audioNavInstance;
}