using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Diagnostics;
using System.Threading.Tasks;
using Newtonsoft.Json;

public class CommandPipe
{


    [JsonPropertyAttribute("pipe")]
    public Command[] Pipe { get; set; }


    [JsonPropertyAttribute("working_dir")]
    public string WorkingDir { get; set; }

    public virtual int Run()
    {
        Process latest = null;
        Queue<Process> runQueue = new Queue<Process>();
        Queue<Task> joints = new Queue<Task>();
        if (Pipe.Length == 0) return -1;
        if (Pipe.Length == 1)
        {
            latest = Pipe[0].Start();
            latest.WaitForExit();
            return latest.ExitCode;
        }

        for (int i = 0; i < Pipe.Length; i++)
        {
            Process newProcess = null;
            var cmd = Pipe[i];
            bool isNotLast = (i + 1) >= Pipe.Length;

            if (latest != null) // i.e. isNotFirst
            {
                newProcess = cmd.Start(WorkingDir, true, isNotLast);
                var jt = Task.Run(async () =>
                {
                    while (!latest.HasExited && !newProcess.HasExited)
                    {
                        string line = await latest.StandardOutput.ReadLineAsync();
                        if (line != null)
                            await newProcess.StandardInput.WriteLineAsync(line);
                    }
                });
                joints.Enqueue(jt);
            }
            else
            {
                newProcess = cmd.Start(WorkingDir, false, isNotLast);
                Task ending = Task.Run(() => { latest.WaitForExit(); });
                joints.Enqueue(ending);
            }
            latest = newProcess;
            runQueue.Enqueue(latest);
        }
        while (runQueue.Count > 0)
            (latest = runQueue.Dequeue()).WaitForExit();
        return latest.ExitCode;
    }
}