using System.Diagnostics;
using System.Text;

namespace MkvPropEditWrapper.Utils;

public sealed class ProcessRunner
{
    private readonly ProcessStartInfo _startInfo;

    public ProcessRunner(ProcessStartInfo startInfo)
    {
        _startInfo = startInfo;

        _startInfo.RedirectStandardOutput = true;
        _startInfo.RedirectStandardError = true;
        _startInfo.StandardOutputEncoding = Encoding.UTF8;
        _startInfo.StandardErrorEncoding = Encoding.UTF8;
    }

    public bool TryRun(out string output)
    {
        using var process = Process.Start(_startInfo);

        var outputBuilder = new StringBuilder();
        var errorBuilder = new StringBuilder();

        if (process is null)
        {
            output = "";

            return false;
        }

        process.OutputDataReceived += (_, args) =>
        {
            outputBuilder.AppendLine(args.Data);
        };

        process.ErrorDataReceived += (_, args) =>
        {
            errorBuilder.AppendLine(args.Data);
        };

        process.BeginOutputReadLine();
        process.BeginErrorReadLine();

        process.WaitForExit();

        if (process.ExitCode != 0)
        {
            output = BuildError(process, outputBuilder, errorBuilder);

            return false;
        }

        output = outputBuilder.ToString();

        return true;
    }

    public async Task<(bool sucess, string output)> TryRunAsync()
    {
        using var process = Process.Start(_startInfo);

        var outputBuilder = new StringBuilder();
        var errorBuilder = new StringBuilder();

        if (process is null)
        {
            return (false, "");
        }

        process.OutputDataReceived += (_, args) =>
        {
            outputBuilder.AppendLine(args.Data);
        };

        process.ErrorDataReceived += (_, args) =>
        {
            errorBuilder.AppendLine(args.Data);
        };

        process.BeginOutputReadLine();
        process.BeginErrorReadLine();

        await process.WaitForExitAsync();

        return process.ExitCode != 0
            ? (false, BuildError(process, outputBuilder, errorBuilder))
            : (true, outputBuilder.ToString());
    }

    private static string BuildError(Process process, StringBuilder output, StringBuilder error)
    {
        StringBuilder builder = new();

        builder.AppendLine($"Error while running process '{process.StartInfo.FileName} {process.StartInfo.Arguments}'\n");
        builder.AppendLine($"Standard output:\n{output.ToString()}\n");
        builder.AppendLine($"Standard error:\n{error.ToString()}\n");

        return builder.ToString();
    }
}