using System;
using System.IO;

namespace RobotNet10.RobotApp.Xloc;

public static class XlocPaths
{
    private static string GetHomeDir()
    {
        // systemd/Docker services thường chạy với HOME=/root hoặc thiếu HOME
        var home = Environment.GetEnvironmentVariable("HOME");
        if (!string.IsNullOrWhiteSpace(home))
            return home;

        return Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);
    }

    public static string GetXdgDataHome()
    {
        // XDG_DATA_HOME mặc định là $HOME/.local/share
        var xdg = Environment.GetEnvironmentVariable("XDG_DATA_HOME");
        if (!string.IsNullOrWhiteSpace(xdg))
            return xdg;

        return Path.Combine(GetHomeDir(), ".local", "share");
    }

    public static string GetMapsDirectory()
    {
        return Path.Combine(GetXdgDataHome(), "xloc", "resources", "maps");
    }

    /// <summary>
    /// Resolve a map folder name (e.g. "map_20260307_103646") into a pbstream file path.
    /// If <paramref name="mapFilePathOrName"/> is already an absolute existing file, returns it as-is.
    /// </summary>
    public static string? ResolvePbstreamPath(string mapFilePathOrName)
    {
        if (string.IsNullOrWhiteSpace(mapFilePathOrName))
            return null;

        // If caller already provided an absolute pbstream path, just validate it.
        if (Path.IsPathRooted(mapFilePathOrName) && File.Exists(mapFilePathOrName))
            return mapFilePathOrName;

        // Otherwise treat it as a map folder name under the configured maps directory.
        var mapsDir = GetMapsDirectory();
        var mapName = Path.GetFileName(mapFilePathOrName.TrimEnd(Path.DirectorySeparatorChar, '/'));
        if (string.IsNullOrWhiteSpace(mapName))
            return null;

        var mapFolder = Path.Combine(mapsDir, mapName);
        if (!Directory.Exists(mapFolder))
            return null;

        // Prefer canonical name: map.pbstream, then fall back to any *.pbstream.
        var canonical = Path.Combine(mapFolder, "map.pbstream");
        if (File.Exists(canonical))
            return canonical;

        var pbstreams = Directory.GetFiles(mapFolder, "*.pbstream", SearchOption.TopDirectoryOnly);
        return pbstreams.Length > 0 ? pbstreams[0] : null;
    }
}