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

namespace CUETools.Codecs
{
    public class UserDefinedWriter : IAudioDest
    {
        string _path, _encoder, _encoderParams, _encoderMode;
        Process _encoderProcess;
        WAVWriter wrt;
        CyclicBuffer outputBuffer = null;
        bool useTempFile = false;
        string tempFile = null;
        long _finalSampleCount = -1;
        bool closed = false;
        private AudioEncoderSettings m_settings;

        public long Position
        {
            get
            {
                return wrt.Position;
            }
        }

        public long FinalSampleCount
        {
            set { _finalSampleCount = wrt.FinalSampleCount = value; }
        }

        // !!!! Must not start the process in constructor, so that we can set CompressionLevel via Settings!
        public AudioEncoderSettings Settings
        {
            get
            {
                return m_settings;
            }
        }

        public string Path { get { return _path; } }

        public UserDefinedWriter(string path, Stream IO, AudioEncoderSettings settings, string encoder, string encoderParams, string encoderMode, int padding)
        {
            m_settings = settings as AudioEncoderSettings;
            _path = path;
            _encoder = encoder;
            _encoderParams = encoderParams;
            _encoderMode = encoderMode;
            useTempFile = _encoderParams.Contains("%I");
            tempFile = path + ".tmp.wav";

            _encoderProcess = new Process();
            _encoderProcess.StartInfo.FileName = _encoder;
            _encoderProcess.StartInfo.Arguments = _encoderParams.Replace("%O", "\"" + path + "\"").Replace("%M", encoderMode).Replace("%P", padding.ToString()).Replace("%I", "\"" + tempFile + "\"");
            _encoderProcess.StartInfo.CreateNoWindow = true;
            if (!useTempFile)
                _encoderProcess.StartInfo.RedirectStandardInput = true;
            _encoderProcess.StartInfo.UseShellExecute = false;
            if (!_encoderParams.Contains("%O"))
                _encoderProcess.StartInfo.RedirectStandardOutput = true;
            if (useTempFile)
            {
                wrt = new WAVWriter(tempFile, null, new WAVWriterSettings(settings.PCM));
                return;
            }
            bool started = false;
            Exception ex = null;
            try
            {
                started = _encoderProcess.Start();
                if (started)
                    _encoderProcess.PriorityClass = Process.GetCurrentProcess().PriorityClass;
            }
            catch (Exception _ex)
            {
                ex = _ex;
            }
            if (!started)
                throw new Exception(_encoder + ": " + (ex == null ? "please check the path" : ex.Message));
            if (_encoderProcess.StartInfo.RedirectStandardOutput)
            {
                Stream outputStream = new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.Read);
                outputBuffer = new CyclicBuffer(2 * 1024 * 1024, _encoderProcess.StandardOutput.BaseStream, outputStream);
            }
            Stream inputStream = new CyclicBufferOutputStream(_encoderProcess.StandardInput.BaseStream, 128 * 1024);
            wrt = new WAVWriter(path, inputStream, new WAVWriterSettings(settings.PCM));
        }

        public void Close()
        {
            if (closed)
                return;
            closed = true;
            wrt.Close();
            if (useTempFile && (_finalSampleCount < 0 || wrt.Position == _finalSampleCount))
            {
                bool started = false;
                Exception ex = null;
                try
                {
                    started = _encoderProcess.Start();
                    if (started)
                        _encoderProcess.PriorityClass = Process.GetCurrentProcess().PriorityClass;
                }
                catch (Exception _ex)
                {
                    ex = _ex;
                }
                if (!started)
                    throw new Exception(_encoder + ": " + (ex == null ? "please check the path" : ex.Message));
            }
            wrt = null;
            if (!_encoderProcess.HasExited)
                _encoderProcess.WaitForExit();
            if (useTempFile)
                File.Delete(tempFile);
            if (outputBuffer != null)
                outputBuffer.Close();
            if (_encoderProcess.ExitCode != 0)
                throw new Exception(String.Format("{0} returned error code {1}", _encoder, _encoderProcess.ExitCode));
        }

        public void Delete()
        {
            Close();
            File.Delete(_path);
        }

        public void Write(AudioBuffer buff)
        {
            try
            {
                wrt.Write(buff);
            }
            catch (IOException ex)
            {
                if (_encoderProcess.HasExited)
                    throw new IOException(string.Format("{0} has exited prematurely with code {1}", _encoder, _encoderProcess.ExitCode), ex);
                else
                    throw ex;
            }
            //_sampleLen += sampleCount;
        }
    }
}