using DibdProtocol.Transport;

namespace Dabit.Mcp.Config;

/// <summary>
/// MCP 서버가 붙을 전광판 연결 설정. 환경변수(DABIT_*)에서 읽는다.
/// Claude Desktop이 claude_desktop_config.json의 env로 주입하는 것을 기본으로 한다
/// (서버 프로세스의 작업 디렉터리가 불확실하므로 파일보다 환경변수가 견고).
/// </summary>
public sealed record McpConnectionSettings
{
    public TransportType ConnectType { get; init; } = TransportType.TcpClient;
    public string PortName { get; init; } = "COM1";
    public int BaudRate { get; init; } = 9600;
    public string Host { get; init; } = "192.168.0.201";
    public int Port { get; init; } = 5000;
    public int ResponseLatencyMs { get; init; } = 1000;

    /// <summary>환경변수에서 설정을 읽는다. 누락 항목은 기본값.</summary>
    public static McpConnectionSettings FromEnvironment()
    {
        static string? Env(string key) => Environment.GetEnvironmentVariable(key);

        var transport = (Env("DABIT_TRANSPORT") ?? "").Trim().ToLowerInvariant() switch
        {
            "serial" => TransportType.Serial,
            "tcp" or "tcpclient" => TransportType.TcpClient,
            _ => TransportType.TcpClient,
        };

        return new McpConnectionSettings
        {
            ConnectType = transport,
            PortName = Env("DABIT_COM") ?? "COM1",
            BaudRate = int.TryParse(Env("DABIT_BAUD"), out var b) ? b : 9600,
            Host = Env("DABIT_HOST") ?? "192.168.0.201",
            Port = int.TryParse(Env("DABIT_PORT"), out var p) ? p : 5000,
            ResponseLatencyMs = int.TryParse(Env("DABIT_RESPONSE_LATENCY"), out var r) ? r : 1000,
        };
    }

    /// <summary>사람이 읽을 연결 요약 문자열.</summary>
    public string Describe() => ConnectType == TransportType.Serial
        ? $"Serial {PortName} @ {BaudRate}bps (timeout {ResponseLatencyMs}ms)"
        : $"TcpClient {Host}:{Port} (timeout {ResponseLatencyMs}ms)";
}