using System;
using System.Diagnostics;
using System.IO;

namespace AmebaPro3_ControlPanel.Services.Uart;

public static class TeraTermLauncher
{
    public static bool TryLaunch(string? port, int baudRate, out string message)
    {
        if (string.IsNullOrWhiteSpace(port))
        {
            message = "Select a COM port first.";
            return false;
        }

        var exePath = ResolveTeraTermPath();
        if (string.IsNullOrWhiteSpace(exePath))
        {
            message = "Tera Term not found. Set TERATERM_PATH or install it.";
            return false;
        }

        var args = $"/C={port} /BAUD={baudRate}";
        try
        {
            Process.Start(new ProcessStartInfo
            {
                FileName = exePath,
                Arguments = args,
                UseShellExecute = true
            });
            message = "Tera Term launched.";
            return true;
        }
        catch (Exception ex)
        {
            message = $"Failed to start Tera Term: {ex.Message}";
            return false;
        }
    }

    private static string? ResolveTeraTermPath()
    {
        var envPath = Environment.GetEnvironmentVariable("TERATERM_PATH");
        if (!string.IsNullOrWhiteSpace(envPath))
        {
            var candidate = Directory.Exists(envPath)
                ? Path.Combine(envPath, "ttermpro.exe")
                : envPath;

            if (File.Exists(candidate))
            {
                return candidate;
            }
        }

        var programFiles = new[]
        {
            Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles),
            Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86)
        };

        foreach (var root in programFiles)
        {
            if (string.IsNullOrWhiteSpace(root))
            {
                continue;
            }

            var candidate = Path.Combine(root, "teraterm", "ttermpro.exe");
            if (File.Exists(candidate))
            {
                return candidate;
            }
        }

        return "ttermpro.exe";
    }
}