import { useState, useEffect } from "react";
import { useNavigate } from "react-router-dom";
import type { PlaylistNode } from "../types/interfaces";
import { parseXmlFile } from "../services/xmlService";
import { api } from "../services/api";

export const useXmlParser = () => {
  const [playlists, setPlaylists] = useState<PlaylistNode[]>([]);
  const [loading, setLoading] = useState(true);
  const navigate = useNavigate();

  // Load playlist structure from the backend on mount (faster loading)
  useEffect(() => {
    const loadData = async () => {
      try {
        // Load just the structure first for faster initial load
        const loadedPlaylists = await api.getPlaylistStructure();
        setPlaylists(loadedPlaylists);
      } catch (err) {
        console.error("Error loading playlist structure from backend:", err);
        // Fallback to full playlist data if structure endpoint fails
        try {
          const fullPlaylists = await api.getPlaylists();
          setPlaylists(fullPlaylists);
        } catch (fallbackErr) {
          console.error("Error loading full playlists from backend:", fallbackErr);
        }
      } finally {
        setLoading(false);
      }
    };

    loadData();
  }, []);

  const handleFileUpload = async (event: React.ChangeEvent<HTMLInputElement>) => {
    const file = event.target.files?.[0];
    if (!file) return;

    const reader = new FileReader();
    reader.onload = async (e) => {
      const xmlText = e.target?.result as string;
      try {
        const { songs: parsedSongs, playlists: parsedPlaylists } = await parseXmlFile(xmlText);
        
        // Save to backend
        await Promise.all([
          api.saveSongs(parsedSongs),
          api.savePlaylists(parsedPlaylists)
        ]);

        // Navigate to home and refresh the page
        navigate('/');
        window.location.reload();
      } catch (err) {
        console.error("Error processing XML:", err);
      }
    };
    reader.readAsText(file);
  };

  const resetLibrary = async () => {
    setPlaylists([]);
    setLoading(false);
  };

  return {
    playlists,
    setPlaylists,
    handleFileUpload,
    loading,
    resetLibrary,
  };
};