using System.Diagnostics;
using Core.Events;
using Core.Exceptions;

namespace Generator.Infrastructure;

public class CommandExecutor
{

    private readonly Queue<string> _commands;
    private string _invite;
    private DisplayEmitter _emitter;
    
    public CommandExecutor(string invite, DisplayEmitter emitter)
    {
        _commands = new Queue<string>();
        _invite = invite;
        _emitter = emitter;
    }
    
    /// <summary>
    /// Runs a single asynchronous command
    /// </summary>
    /// <param name="command">Command to run</param>
    /// <exception cref="CommandExecutionException">When the command hasn't been terminated successfully</exception>
    public async Task RunAsync(string command)
    {
        await Task.Run(() =>
        {
            using var process = new Process();
            process.StartInfo = new ProcessStartInfo
            {
                FileName = _invite,
                Arguments = $"{command}",
                RedirectStandardOutput = true,
                RedirectStandardError = true,
                WindowStyle = ProcessWindowStyle.Normal
            };
            process.Start();
            ReadOutput(process);
            ReadError(process);
            process.WaitForExit();
        
            if(process.ExitCode == 1) 
                throw new CommandExecutionException($"The following task has failed : \n '{command}'");
        });
    }

    private void ReadError(Process process)
    {
        Task.Run(async () =>
        {
            using var output = process.StandardError;
            while (!output.EndOfStream)
            {
                var line = await output.ReadLineAsync();
                _emitter.Warn(this, line.ToString());    
            }
        });
    }
    
    private void ReadOutput(Process process)
    {
        Task.Run(async () =>
        {
            using var output = process.StandardOutput;
            while (!output.EndOfStream)
            {
                var line = await output.ReadLineAsync();
                _emitter.Say(this, line);          
            }
        });
    }
    
    /// <summary>
    /// Registers a command to execute later
    /// </summary>
    /// <param name="command"></param>
    public void Register(string command) => _commands.Enqueue(command);

    /// <summary>
    /// Runs all previously registered command
    /// </summary>
    public async Task RunRegistered()
    {
        while (_commands.TryDequeue(out var c))
        {
            await RunAsync(c);
        }
    }
}