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

namespace Paca.Tests.Platform;

/// <summary>
/// Paca.Cli 파이프라인 회귀 방지 게이트 테스트 (Phase 5).
/// CLI 옵션 파싱(--help, --dashparse, --dash, HLS), 프로세스 종료 코드 검증.
/// </summary>
public class CliPipelineGateTests
{
    private static string GetSolutionRoot()
    {
        var dir = AppContext.BaseDirectory;
        while (!string.IsNullOrEmpty(dir) && !File.Exists(Path.Combine(dir, "Paca.slnx")) && !File.Exists(Path.Combine(dir, "Paca.sln")))
        {
            var parent = Directory.GetParent(dir);
            if (parent == null) break;
            dir = parent.FullName;
        }
        return dir ?? AppContext.BaseDirectory;
    }

    private static string CliProjectDir => Path.Combine(GetSolutionRoot(), "src", "Paca.Cli");

    [Fact]
    public void Gate_Cli_Program_Source_Contains_All_Required_Pipelines()
    {
        var programPath = Path.Combine(CliProjectDir, "Program.cs");
        Assert.True(File.Exists(programPath), $"Program.cs must exist at {programPath}");

        var content = File.ReadAllText(programPath);

        // 핵심 CLI 옵션 검증
        Assert.Contains("--help", content);
        Assert.Contains("-h", content);
        Assert.Contains("--dashparse", content);
        Assert.Contains("--dash", content);
        Assert.Contains("HlsDownloader", content);
        Assert.Contains("DashDownloader", content);
    }

    [Fact]
    public async Task Gate_Cli_Help_Command_Exits_With_Code_Zero()
    {
        var root = GetSolutionRoot();
        var psi = new ProcessStartInfo
        {
            FileName = "dotnet",
            Arguments = "run --project src/Paca.Cli --no-build -- -h",
            WorkingDirectory = root,
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            UseShellExecute = false,
            CreateNoWindow = true
        };

        using var process = new Process { StartInfo = psi };
        process.Start();

        var outputTask = process.StandardOutput.ReadToEndAsync();
        var errorTask = process.StandardError.ReadToEndAsync();

        using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(30));
        await process.WaitForExitAsync(cts.Token);

        var stdout = await outputTask;
        var stderr = await errorTask;

        Assert.Equal(0, process.ExitCode);
        Assert.Contains("Usage: dotnet run", stdout);
    }

    [Fact]
    public async Task Gate_Cli_NoArgs_Prints_Usage_And_Exits_Zero()
    {
        var root = GetSolutionRoot();
        var psi = new ProcessStartInfo
        {
            FileName = "dotnet",
            Arguments = "run --project src/Paca.Cli --no-build",
            WorkingDirectory = root,
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            UseShellExecute = false,
            CreateNoWindow = true
        };

        using var process = new Process { StartInfo = psi };
        process.Start();

        var outputTask = process.StandardOutput.ReadToEndAsync();
        using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(30));
        await process.WaitForExitAsync(cts.Token);
        var stdout = await outputTask;

        Assert.Equal(0, process.ExitCode);
        Assert.Contains("Usage: dotnet run", stdout);
    }
}