using System.Text;
using System.Text.Json;
using Discord;
using Discord.Interactions;
using TentacleBot.Services;

namespace TentacleBot.Commands;

[Group("palworld", "Palworld server status commands")]
public class PalworldCommands : InteractionModuleBase<SocketInteractionContext>
{
    private readonly PalworldApiService _palworldApi;

    public PalworldCommands(PalworldApiService palworldApi)
    {
        _palworldApi = palworldApi;
    }

    [SlashCommand("status", "Show a combined server status dashboard")]
    public async Task HandleStatusAsync()
    {
        await DeferAsync();

        var infoTask = _palworldApi.GetInfoAsync();
        var metricsTask = _palworldApi.GetMetricsAsync();
        var playersTask = _palworldApi.GetPlayersAsync();

        var info = await infoTask;
        var metrics = await metricsTask;
        var players = await playersTask;

        if (info is null && metrics is null && players is null)
        {
            await FollowupAsync(embed: new EmbedBuilder()
                .WithTitle("Palworld Server Status")
                .WithDescription("Failed to connect to the Palworld server. Check that the server is running and the REST API is enabled.")
                .WithColor(Color.Red)
                .WithTimestamp(DateTimeOffset.UtcNow)
                .Build());
            return;
        }

        var embed = new EmbedBuilder()
            .WithTitle("Palworld Server Status")
            .WithColor(Color.DarkGreen)
            .WithTimestamp(DateTimeOffset.UtcNow);

        if (info is not null)
        {
            var root = info.RootElement;
            var name = GetString(root, "servername");
            var version = GetString(root, "version");

            if (!string.IsNullOrWhiteSpace(name))
                embed.AddField("Server Name", name, true);
            if (!string.IsNullOrWhiteSpace(version))
                embed.AddField("Version", version, true);
        }

        if (metrics is not null)
        {
            var root = metrics.RootElement;
            embed.AddField("Players", $"{GetInt(root, "currentplayernum")} / {GetInt(root, "maxplayernum")}", true);
            embed.AddField("FPS", $"{GetDouble(root, "serverfps")}", true);

            var uptime = GetInt(root, "uptime");
            embed.AddField("Uptime", FormatUptime(uptime), true);

            var days = GetInt(root, "days");
            embed.AddField("In-Game Days", $"{days}", true);

            var camps = GetInt(root, "basecampnum");
            embed.AddField("Base Camps", $"{camps}", true);
        }

        if (players is not null)
        {
            var playerList = players.RootElement.GetProperty("players");
            var count = playerList.GetArrayLength();

            if (count > 0)
            {
                var sb = new StringBuilder();
                var limit = Math.Min(count, 15);
                for (var i = 0; i < limit; i++)
                {
                    var p = playerList[i];
                    var name = GetString(p, "name");
                    var level = GetInt(p, "level");
                    sb.AppendLine($"**{name}** (Lv.{level})");
                }
                if (count > 15)
                    sb.AppendLine($"*...and {count - 15} more*");
                embed.AddField($"Online Players ({count})", sb.ToString());
            }
            else
            {
                embed.AddField("Online Players", "None");
            }
        }

        await FollowupAsync(embed: embed.Build());
    }

    [SlashCommand("info", "Get Palworld server information")]
    public async Task HandleInfoAsync()
    {
        await DeferAsync();

        var data = await _palworldApi.GetInfoAsync();

        if (data is null)
        {
            await FollowupAsync(embed: ErrorEmbed("info"));
            return;
        }

        var root = data.RootElement;
        var embed = new EmbedBuilder()
            .WithTitle("Server Info")
            .WithColor(Color.Blue)
            .AddField("Server Name", GetString(root, "servername") ?? "N/A", true)
            .AddField("Version", GetString(root, "version") ?? "N/A", true)
            .AddField("Description", GetString(root, "description") ?? "N/A")
            .AddField("World GUID", GetString(root, "worldguid") ?? "N/A")
            .WithTimestamp(DateTimeOffset.UtcNow)
            .Build();

        await FollowupAsync(embed: embed);
    }

    [SlashCommand("players", "Get the list of online players")]
    public async Task HandlePlayersAsync()
    {
        await DeferAsync();

        var data = await _palworldApi.GetPlayersAsync();

        if (data is null)
        {
            await FollowupAsync(embed: ErrorEmbed("players"));
            return;
        }

        var players = data.RootElement.GetProperty("players");
        var embed = new EmbedBuilder()
            .WithTitle("Online Players")
            .WithColor(Color.Green)
            .WithTimestamp(DateTimeOffset.UtcNow);

        var count = players.GetArrayLength();

        if (count == 0)
        {
            embed.WithDescription("No players are currently online.");
        }
        else
        {
            var sb = new StringBuilder();
            var limit = Math.Min(count, 20);
            for (var i = 0; i < limit; i++)
            {
                var p = players[i];
                var name = GetString(p, "name");
                var level = GetInt(p, "level");
                var ping = GetDouble(p, "ping");
                sb.AppendLine($"{i + 1}. **{name}** — Lv.{level} — {ping:F0}ms ping");
            }
            if (count > 20)
                sb.AppendLine($"*...and {count - 20} more*");
            embed.WithDescription(sb.ToString());
        }

        await FollowupAsync(embed: embed.Build());
    }

    [SlashCommand("metrics", "Get Palworld server performance metrics")]
    public async Task HandleMetricsAsync()
    {
        await DeferAsync();

        var data = await _palworldApi.GetMetricsAsync();

        if (data is null)
        {
            await FollowupAsync(embed: ErrorEmbed("metrics"));
            return;
        }

        var root = data.RootElement;

        var embed = new EmbedBuilder()
            .WithTitle("Server Metrics")
            .WithColor(Color.Orange)
            .AddField("FPS", $"{GetDouble(root, "serverfps"):F1}", true)
            .AddField("Frame Time", $"{GetDouble(root, "serverframetime"):F2}ms", true)
            .AddField("Players", $"{GetInt(root, "currentplayernum")} / {GetInt(root, "maxplayernum")}", true)
            .AddField("Uptime", FormatUptime(GetInt(root, "uptime")), true)
            .AddField("In-Game Days", $"{GetInt(root, "days")}", true)
            .AddField("Base Camps", $"{GetInt(root, "basecampnum")}", true)
            .WithTimestamp(DateTimeOffset.UtcNow)
            .Build();

        await FollowupAsync(embed: embed);
    }

    private static string FormatUptime(int seconds)
    {
        if (seconds <= 0) return "N/A";

        var ts = TimeSpan.FromSeconds(seconds);
        var parts = new List<string>();
        if (ts.Days > 0) parts.Add($"{ts.Days}d");
        if (ts.Hours > 0) parts.Add($"{ts.Hours}h");
        if (ts.Minutes > 0) parts.Add($"{ts.Minutes}m");
        if (parts.Count == 0) parts.Add($"{ts.Seconds}s");
        return string.Join(" ", parts);
    }

    private static Embed ErrorEmbed(string endpoint)
    {
        return new EmbedBuilder()
            .WithTitle($"Failed to fetch {endpoint}")
            .WithDescription("Could not connect to the Palworld server. Verify the server is running and REST API is enabled.")
            .WithColor(Color.Red)
            .WithTimestamp(DateTimeOffset.UtcNow)
            .Build();
    }

    private static string? GetString(JsonElement element, string property)
    {
        return element.TryGetProperty(property, out var prop) && prop.ValueKind == JsonValueKind.String
            ? prop.GetString()
            : null;
    }

    private static int GetInt(JsonElement element, string property)
    {
        return element.TryGetProperty(property, out var prop) && prop.ValueKind == JsonValueKind.Number
            ? prop.GetInt32()
            : 0;
    }

    private static double GetDouble(JsonElement element, string property)
    {
        return element.TryGetProperty(property, out var prop) && prop.ValueKind == JsonValueKind.Number
            ? prop.GetDouble()
            : 0;
    }
}