/**
 * iTunes Search API integration for fetching release years
 * API Documentation: https://performance-partners.apple.com/search-api
 */

interface ItunesResult {
    wrapperType: string;
    kind: string;
    artistName: string;
    collectionName: string;
    trackName: string;
    releaseDate: string;
    primaryGenreName: string;
}

interface ItunesResponse {
    resultCount: number;
    results: ItunesResult[];
}

/**
 * Get the earliest release year for a song from iTunes
 * @param artist Artist name
 * @param title Song title
 * @returns Release year or null if not found
 */
export async function getReleaseYearFromItunes(artist: string, title: string): Promise<number | null> {
    try {
        // Construct search URL
        // entity=song ensures we get individual tracks
        // limit=10 to get a good range of potential matches (originals, remasters, best ofs)
        const term = encodeURIComponent(`${artist} ${title}`);
        const url = `https://itunes.apple.com/search?term=${term}&entity=song&limit=10`;

        const response = await fetch(url, {
            headers: {
                'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36'
            }
        });

        if (!response.ok) {
            console.error(`iTunes API error: ${response.status} ${response.statusText}`);
            return null;
        }

        const data: ItunesResponse = await response.json();

        if (data.resultCount === 0) {
            return null;
        }

        // Filter for exact(ish) matches to avoid wrong songs
        // and find the earliest release date
        let earliestYear: number | null = null;
        const normalizedTitle = title.toLowerCase().replace(/[^\w\s]/g, '');
        const normalizedArtist = artist.toLowerCase().replace(/[^\w\s]/g, '');

        for (const result of data.results) {
            // Basic validation that it's the right song
            const resTitle = result.trackName.toLowerCase().replace(/[^\w\s]/g, '');
            const resArtist = result.artistName.toLowerCase().replace(/[^\w\s]/g, '');

            // Check if title and artist are contained in the result (fuzzy match)
            if (resTitle.includes(normalizedTitle) && resArtist.includes(normalizedArtist)) {
                if (result.releaseDate) {
                    const year = new Date(result.releaseDate).getFullYear();
                    if (!isNaN(year)) {
                        if (earliestYear === null || year < earliestYear) {
                            earliestYear = year;
                        }
                    }
                }
            }
        }

        return earliestYear;

    } catch (error) {
        console.error(`Error fetching release year from iTunes for "${title}" by "${artist}":`, error);
        return null;
    }
}