using System.Reflection;
using System.Text.Json;
using CounterStrikeSharp.API.Core;
using CounterStrikeSharp.API.Modules.Admin;
using CounterStrikeSharp.API.Modules.Utils;

namespace Whisper;

// Reads CS2-Tags' tags.json so private messages show the same rank prefix and colours as chat, and
// picks a player's tag the way CS2-Tags does: their SteamID64 first, then the first "#group" or
// "@permission" key they match in file order, then "everyone". Reread when the file changes.
public sealed class Tags(string path, Action<string> warn)
{
    public sealed record Tag(string Prefix, string NickColor, string MessageColor);

    private List<KeyValuePair<string, Tag>> _tags = [];
    private DateTime _loadedWrite;

    public Tag? Find(CCSPlayerController player)
    {
        Refresh();
        if (player.IsBot || player.IsHLTV || player.AuthorizedSteamID == null)
            return null;

        var steamid = player.AuthorizedSteamID.SteamId64.ToString();
        foreach (var (key, tag) in _tags)
            if (key == steamid)
                return tag;
        foreach (var (key, tag) in _tags)
        {
            if (key.StartsWith('#') && AdminManager.PlayerInGroup(player, key)) return tag;
            if (key.StartsWith('@') && AdminManager.PlayerHasPermissions(player, key)) return tag;
        }
        foreach (var (key, tag) in _tags)
            if (key == "everyone")
                return tag;
        return null;
    }

    private void Refresh()
    {
        DateTime written;
        try
        {
            written = File.GetLastWriteTimeUtc(path);
        }
        catch (Exception)
        {
            return;
        }
        // GetLastWriteTimeUtc gives 1601 for a missing file.
        if (written == _loadedWrite || written.Year < 1700)
        {
            if (written.Year < 1700 && _tags.Count > 0)
                _tags = [];
            _loadedWrite = written;
            return;
        }
        _loadedWrite = written;
        try
        {
            using var doc = JsonDocument.Parse(File.ReadAllText(path),
                new JsonDocumentOptions { CommentHandling = JsonCommentHandling.Skip, AllowTrailingCommas = true });
            var tags = new List<KeyValuePair<string, Tag>>();
            if (doc.RootElement.TryGetProperty("tags", out var section))
                foreach (var entry in section.EnumerateObject())
                    tags.Add(new(entry.Name, new Tag(Str(entry.Value, "prefix"), Str(entry.Value, "nick_color"), Str(entry.Value, "message_color"))));
            _tags = tags;
        }
        catch (Exception ex)
        {
            // Keep the tags from before, as CS2-Tags does with a broken file.
            warn($"Couldn't read {path}: {ex.Message}; keeping the previous tags");
        }
    }

    private static string Str(JsonElement e, string name) =>
        e.TryGetProperty(name, out var v) && v.ValueKind == JsonValueKind.String ? v.GetString() ?? "" : "";

    public static string TeamColor(int team) => team switch
    {
        (int)CsTeam.Terrorist => ChatColors.Gold.ToString(),
        (int)CsTeam.CounterTerrorist => ChatColors.Blue.ToString(),
        _ => "",
    };

    // Colour tags in config strings only, never in names or messages: {Red}, {Default}, {TEAMCOLOR}.
    public static string Colors(string text, int team = 0)
    {
        if (!text.Contains('{'))
            return text;
        foreach (var field in typeof(ChatColors).GetFields(BindingFlags.Public | BindingFlags.Static))
            if (field.FieldType == typeof(char))
                text = text.Replace($"{{{field.Name}}}", field.GetValue(null)!.ToString(), StringComparison.OrdinalIgnoreCase);
        return text.Replace("{TEAMCOLOR}", TeamColor(team), StringComparison.OrdinalIgnoreCase);
    }
}