using System.Net.Http.Headers;
using System.Text.Json;
using System.Text.RegularExpressions;
using CVRManager.Models;

namespace CVRManager.Services;

public record CvrmgMod(
    int Id, string Name, string[] Aliases, string Category, string ModVersion, string GameVersion, string LoaderVersion,
    string Type, string Author, string Description, string DownloadLink, string SourceLink, string Hash, int ApprovalStatus, DateTime Updated)
{
    public string StatusText => ApprovalStatus switch { 1 => "approved", 2 => "outdated", 3 => "obsolete", _ => "unknown" };
    public string ModType => Type.Equals("Plugin", StringComparison.OrdinalIgnoreCase) ? "Plugins" : "Mods";
}

public class CvrmgService
{
    const string ListUrl = "https://api.cvrmg.com/v1/mods";
    readonly HttpClient http = new();
    List<CvrmgMod>? cache;
    DateTime fetched;

    public CvrmgService()
    {
        http.DefaultRequestHeaders.UserAgent.Add(new ProductInfoHeaderValue("CVRManager", "1.0"));
    }

    public static string Normalize(string s) => Regex.Replace(s ?? "", "[^a-z0-9]", "", RegexOptions.IgnoreCase).ToLowerInvariant();

    public async Task<List<CvrmgMod>> GetAllAsync(CancellationToken ct, bool force = false)
    {
        if (!force && cache != null && DateTime.UtcNow - fetched < TimeSpan.FromMinutes(10)) return cache;
        var path = Path.Combine(Paths.Root, "sources", "cvrmg.json");
        string? json = null;
        if (!force && File.Exists(path) && DateTime.UtcNow - File.GetLastWriteTimeUtc(path) < TimeSpan.FromHours(1))
            json = await File.ReadAllTextAsync(path, ct);
        if (json == null)
        {
            try
            {
                using var resp = await http.GetAsync(ListUrl, ct);
                if (!resp.IsSuccessStatusCode) throw new InvalidOperationException($"CVRMG returned {(int)resp.StatusCode}.");
                json = await resp.Content.ReadAsStringAsync(ct);
                Directory.CreateDirectory(Path.GetDirectoryName(path)!);
                await File.WriteAllTextAsync(path, json, ct);
            }
            catch (Exception e) when (e is not OperationCanceledException && File.Exists(path))
            {
                json = await File.ReadAllTextAsync(path, ct);
            }
        }
        using var doc = JsonDocument.Parse(json);
        var list = new List<CvrmgMod>();
        foreach (var m in doc.RootElement.EnumerateArray())
        {
            if (!m.TryGetProperty("versions", out var versions) || versions.ValueKind != JsonValueKind.Array) continue;
            JsonElement? best = null;
            var bestNo = int.MinValue;
            foreach (var v in versions.EnumerateArray())
            {
                var no = v.TryGetProperty("_version", out var n) && n.ValueKind == JsonValueKind.Number ? n.GetInt32() : 0;
                if (no >= bestNo) { best = v; bestNo = no; }
            }
            if (best is not { } ver) continue;

            string S(JsonElement e, string k) => e.TryGetProperty(k, out var p) && p.ValueKind == JsonValueKind.String ? p.GetString() ?? "" : "";
            var aliases = m.TryGetProperty("aliases", out var al) && al.ValueKind == JsonValueKind.Array
                ? al.EnumerateArray().Where(a => a.ValueKind == JsonValueKind.String).Select(a => a.GetString()!).ToArray()
                : Array.Empty<string>();
            DateTime.TryParse(S(ver, "updateDate"), null, System.Globalization.DateTimeStyles.AdjustToUniversal, out var updated);
            list.Add(new CvrmgMod(
                m.GetProperty("_id").GetInt32(), S(ver, "name"), aliases, S(m, "category"),
                S(ver, "modVersion"), S(ver, "gameVersion"), S(ver, "loaderVersion").TrimStart('v'), S(ver, "modType"),
                S(ver, "author"), S(ver, "description"), S(ver, "downloadLink"), S(ver, "sourceLink"), S(ver, "hash"),
                ver.TryGetProperty("approvalStatus", out var st) && st.ValueKind == JsonValueKind.Number ? st.GetInt32() : 0, updated));
        }
        cache = list;
        fetched = DateTime.UtcNow;
        return list;
    }

    public static ReleaseInfo ToRelease(CvrmgMod m, string fileName) => new()
    {
        Tag = m.ModVersion,
        Published = m.Updated,
        GameVersion = m.GameVersion,
        LoaderVersion = m.LoaderVersion,
        Assets = { new AssetInfo { Name = fileName, Url = m.DownloadLink, Hash = m.Hash } },
    };

    public static void ApplyMeta(ModDef def, CvrmgMod m)
    {
        def.CvrmgId = m.Id;
        if (def.Author.Length == 0) def.Author = m.Author;
        def.Description = m.Description;
        def.LatestVersion = m.ModVersion;
        def.Category = m.Category;
        def.Status = m.StatusText;
        if (def.SourceLink.Length == 0) def.SourceLink = m.SourceLink;
    }
}