// Home screen data store - featured items, continue watching, recently added
// TRACES: UR-023, UR-024, UR-034 | DR-026, DR-027, DR-038, DR-039
import { writable, derived } from "svelte/store";
import type { MediaItem } from "$lib/api/types";
import { auth } from "./auth";

interface HomeState {
  heroItems: MediaItem[];
  resumeItems: MediaItem[];
  nextUpItems: MediaItem[];
  latestItems: MediaItem[];
  recentlyPlayedAudio: MediaItem[];
  resumeMovies: MediaItem[];
  isLoading: boolean;
  error: string | null;
}

function createHomeStore() {
  const initialState: HomeState = {
    heroItems: [],
    resumeItems: [],
    nextUpItems: [],
    latestItems: [],
    recentlyPlayedAudio: [],
    resumeMovies: [],
    isLoading: false,
    error: null,
  };

  const { subscribe, set, update } = writable<HomeState>(initialState);

  async function loadHomeSections() {
    // Only show loading spinner when no data is available yet
    update(s => ({ ...s, isLoading: s.heroItems.length === 0 && s.latestItems.length === 0, error: null }));

    try {
      const repo = auth.getRepository();

      const [resume, nextUp, latest, recentAudio, resumeMovies] = await Promise.all([
        repo.getResumeItems(undefined, 12),
        repo.getNextUpEpisodes(undefined, 12),
        repo.getLatestItems("", 16),
        repo.getRecentlyPlayedAudio(12), // Backend now handles intelligent grouping
        repo.getResumeMovies(12),
      ]);

      // Use resume items or latest as hero items
      const hero = resume.length >= 3 ? resume.slice(0, 5) : latest.slice(0, 5);

      update(s => ({
        ...s,
        heroItems: hero,
        resumeItems: resume,
        nextUpItems: nextUp,
        latestItems: latest,
        recentlyPlayedAudio: recentAudio,
        resumeMovies: resumeMovies,
        isLoading: false,
      }));
    } catch (error) {
      const message = error instanceof Error ? error.message : "Failed to load home sections";
      update(s => ({ ...s, isLoading: false, error: message }));
      console.error("Failed to load home sections:", error);
    }
  }

  function reset() {
    set(initialState);
  }

  return {
    subscribe,
    loadHomeSections,
    reset,
  };
}

export const home = createHomeStore();

// Derived stores for convenience
export const heroItems = derived(home, $home => $home.heroItems);
export const resumeItems = derived(home, $home => $home.resumeItems);
export const nextUpItems = derived(home, $home => $home.nextUpItems);
export const latestItems = derived(home, $home => $home.latestItems);
export const recentlyPlayedAudio = derived(home, $home => $home.recentlyPlayedAudio);
export const resumeMovies = derived(home, $home => $home.resumeMovies);
export const isHomeLoading = derived(home, $home => $home.isLoading);