using System.Net.Http.Json;
using System.Reflection;
using System.Text.RegularExpressions;
using System.Text.Json.Serialization;

namespace LMEMappeCatastaliApp.Services;

public sealed class AppUpdateService
{
    private const string ReleasesUrl = "https://gitea.lmcloud.it/api/v1/repos/livio/LMEMappeCatastaliProApp/releases?limit=50";
    private static readonly Regex ProTagPattern = new(
        @"^v?(?<version>\d+\.\d+\.\d+)-pro(?:[-.].*)?$",
        RegexOptions.Compiled | RegexOptions.IgnoreCase | RegexOptions.CultureInvariant);
    private readonly HttpClient _httpClient = new() { Timeout = TimeSpan.FromSeconds(20) };

    public static string CurrentVersion =>
        typeof(AppUpdateService).Assembly
            .GetCustomAttribute<AssemblyInformationalVersionAttribute>()?
            .InformationalVersion.Split('+')[0]
        ?? AppInfo.Current.VersionString;

    public async Task<AppUpdateResult> CheckAsync(CancellationToken cancellationToken = default)
    {
        var releases = await _httpClient.GetFromJsonAsync<GiteaRelease[]>(ReleasesUrl, cancellationToken)
            ?? throw new InvalidDataException("Risposta aggiornamenti non valida.");
        GiteaRelease? selectedRelease = null;
        GiteaAsset? selectedApk = null;
        Version? selectedVersion = null;
        foreach (var release in releases.Where(item => !item.Draft))
        {
            var match = ProTagPattern.Match(release.TagName ?? string.Empty);
            var apk = release.Assets?.FirstOrDefault(item => IsProApk(item.Name));
            if (!match.Success || apk is null || !Version.TryParse(match.Groups["version"].Value, out var version))
            {
                continue;
            }

            if (selectedVersion is null || version > selectedVersion)
            {
                selectedRelease = release;
                selectedApk = apk;
                selectedVersion = version;
            }
        }

        if (selectedRelease is null || selectedApk is null || selectedVersion is null)
        {
            throw new InvalidDataException("Nessuna release compatibile con LME Mappe Catastali Pro trovata.");
        }

        _ = Version.TryParse(CurrentVersion, out var current);
        return new(
            current is not null && selectedVersion > current,
            selectedVersion.ToString(3),
            selectedRelease.HtmlUrl ?? string.Empty,
            selectedApk.BrowserDownloadUrl ?? selectedRelease.HtmlUrl ?? string.Empty,
            selectedRelease.Body ?? string.Empty);
    }

    private static bool IsProApk(string? name) =>
        name?.StartsWith("LME-Mappe-Catastali-Pro-", StringComparison.OrdinalIgnoreCase) == true
        && name.EndsWith(".apk", StringComparison.OrdinalIgnoreCase);

    private sealed class GiteaRelease
    {
        [JsonPropertyName("tag_name")] public string? TagName { get; set; }
        [JsonPropertyName("html_url")] public string? HtmlUrl { get; set; }
        [JsonPropertyName("assets")] public GiteaAsset[]? Assets { get; set; }
        [JsonPropertyName("body")] public string? Body { get; set; }
        [JsonPropertyName("draft")] public bool Draft { get; set; }
    }

    private sealed class GiteaAsset
    {
        [JsonPropertyName("name")] public string? Name { get; set; }
        [JsonPropertyName("browser_download_url")] public string? BrowserDownloadUrl { get; set; }
    }
}

public sealed record AppUpdateResult(bool IsAvailable, string Version, string ReleaseUrl, string DownloadUrl, string ReleaseNotes);