using TuneRipper.Shared.Models;
using System.Text.RegularExpressions;
using System.Net.Http;
using System.Threading.Tasks;
using System.Text.RegularExpressions;

namespace TuneRipper.Api.Services;

public interface IVideoService
{
    Task<YouTubeVideoDetails?> GetVideoDetailsAsync(string url);
    bool IsValidYouTubeUrl(string url);
    string ExtractVideoId(string url);
}

public class VideoService : IVideoService
{
    private readonly ILogger<VideoService> _logger;
    private readonly HttpClient _httpClient;

    public VideoService(ILogger<VideoService> logger)
    {
        _logger = logger;
        _httpClient = new HttpClient();
    }

    public async Task<YouTubeVideoDetails?> GetVideoDetailsAsync(string url)
    {
        try
        {
            if (!IsValidYouTubeUrl(url))
            {
                _logger.LogWarning("Invalid YouTube URL: {Url}", url);
                return null;
            }

            var videoId = ExtractVideoId(url);
            var thumbnailUrl = $"https://img.youtube.com/vi/{videoId}/maxresdefault.jpg";
            string? title = null;

            // Fetch HTML and parse title
            try
            {
                var html = await _httpClient.GetStringAsync(url);
                // Try OpenGraph title first
                var ogTitleMatch = Regex.Match(html, "<meta property='og:title' content='(.*?)'", RegexOptions.IgnoreCase);
                if (!ogTitleMatch.Success)
                {
                    ogTitleMatch = Regex.Match(html, "<meta property=\"og:title\" content=\"(.*?)\"", RegexOptions.IgnoreCase);
                }
                if (ogTitleMatch.Success)
                {
                    title = ogTitleMatch.Groups[1].Value;
                }
                else
                {
                    // Fallback to <title>
                    var titleMatch = Regex.Match(html, "<title>(.*?)</title>", RegexOptions.IgnoreCase);
                    if (titleMatch.Success)
                    {
                        title = titleMatch.Groups[1].Value.Replace(" - YouTube", "").Trim();
                    }
                }
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "Failed to fetch or parse video title for {Url}", url);
                title = $"YouTube Video {videoId}";
            }

            var videoDetails = new YouTubeVideoDetails
            {
                Id = videoId,
                Title = title,
                ThumbnailUrl = thumbnailUrl
            };

            _logger.LogInformation("Fetched image and title for video {VideoId}", videoId);
            return videoDetails;
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error fetching video details for URL: {Url}", url);
            return null;
        }
    }

    public bool IsValidYouTubeUrl(string url)
    {
        if (string.IsNullOrWhiteSpace(url))
            return false;

        var patterns = new[]
        {
            @"^https?://(www\.)?youtube\.com/watch\?v=[\w-]+",
            @"^https?://(www\.)?youtu\.be/[\w-]+",
            @"^https?://(www\.)?youtube\.com/embed/[\w-]+",
            @"^https?://(www\.)?youtube\.com/v/[\w-]+"
        };

        return patterns.Any(pattern => Regex.IsMatch(url, pattern, RegexOptions.IgnoreCase));
    }

    public string ExtractVideoId(string url)
    {
        if (string.IsNullOrWhiteSpace(url))
            return string.Empty;

        try
        {
            var patterns = new Dictionary<string, string>
            {
                { @"youtu\.be/([^?&]+)", "$1" },
                { @"youtube\.com/watch\?v=([^&]+)", "$1" },
                { @"youtube\.com/embed/([^?&]+)", "$1" },
                { @"youtube\.com/v/([^?&]+)", "$1" }
            };

            foreach (var pattern in patterns)
            {
                var match = Regex.Match(url, pattern.Key, RegexOptions.IgnoreCase);
                if (match.Success)
                {
                    return match.Groups[1].Value;
                }
            }
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error extracting video ID from URL: {Url}", url);
        }

        return string.Empty;
    }
}