using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;

namespace AudioPlayer
{
    class MP3Player
    {
        [DllImport("winmm.dll")]
        private static extern int mciSendString(String command, StringBuilder buffer, int bufferSize, IntPtr hwndCallback);

        private string m_szFilePath = "";
        public string FilePath
        {
            get
            {
                return FilePath;
            }
        }

        private int m_iError = 0;
        public int LastErrorCode
        {
            get
            {
                return m_iError;
            }
        }

        private ulong m_ulLength = 0;
        public ulong AudioLength
        {
            get
            {
                if (m_bOpened == true)
                {
                    return m_ulLength;
                }
                else
                {
                    return 0;
                }
            }
        }

        private bool m_bOpened = false;
        private bool m_bPlaying = false;
        private bool m_bPaused = false;
        private bool m_bLoop = false;

        private void SendString(string szCommand)
        {
            int iError = mciSendString(szCommand, null, 0, IntPtr.Zero);
            if (iError != 0) m_iError = iError;
        }

        private void CalculateLength()
        {
            StringBuilder sb = new StringBuilder(128);
            mciSendString("status MediaFile length", sb, 128, IntPtr.Zero);
            m_ulLength = Convert.ToUInt64(sb.ToString());
        }

        public void Open(string szFilePath)
        {
            if (m_bOpened == false)
            {
                SendString("open \"" + szFilePath + "\" type mpegvideo alias MediaFile");
                m_szFilePath = szFilePath;
                m_bOpened = true;
                m_bPlaying = false;
                m_bPaused = false;
                SendString("set MediaFile time format milliseconds");
                SendString("set MediaFile seek exactly on");
                CalculateLength();
            }
            else
            {
                Close();
                Open(szFilePath);
            }
        }

        public void Close()
        {
            if (m_bOpened == true)
            {
                SendString("close MediaFile");
                m_bOpened = false;
                m_bPlaying = false;
                m_bPaused = false;
            }
        }

        public void Seek(ulong ulMillisecs)
        {
            if (m_bOpened == true && m_bPlaying == true && ulMillisecs <= m_ulLength)
            {
                if (m_bPaused == true)
                {
                    SendString(String.Format("seek MediaFile to {0}", ulMillisecs));
                }
                else
                {
                    SendString(String.Format("seek MediaFile to {0}", ulMillisecs));

                    if (m_bLoop == true)
                    {
                        SendString("play MediaFile REPEAT");
                    }
                    else
                    {
                        SendString("play MediaFile");
                    }
                }
            }
        }

        public void Play()
        {
            if (m_bOpened == true)
            {
                if (m_bPlaying == false)
                {
                    m_bPlaying = true;
                    SendString("play MediaFile");
                }
                else
                {
                    if (m_bPaused == false)
                    {
                        SendString("seek MediaFile to start");
                        SendString("play MediaFile");
                    }
                    else
                    {
                        m_bPaused = false;
                        SendString("play MediaFile");
                    }
                }
            }
        }

        public void LoopPlay()
        {
            if (m_bOpened == true)
            {
                m_bLoop = true;

                if (m_bPlaying == false)
                {
                    m_bPlaying = true;
                    SendString("play MediaFile REPEAT");
                }
                else
                {
                    if (m_bPaused == false)
                    {
                        SendString("seek MediaFile to start");
                        SendString("play MediaFile REPEAT");
                    }
                    else
                    {
                        m_bPaused = false;
                        SendString("play MediaFile REPEAT");
                    }
                }
            }
        }

        public void Pause()
        {
            if (m_bOpened == true)
            {
                if (m_bPaused == false)
                {
                    m_bPaused = true;
                    SendString("pause MediaFile");
                }
                else
                {
                    m_bPaused = false;

                    if (m_bLoop == true)
                    {
                        SendString("play MediaFile REPEAT");
                    }
                    else
                    {
                        SendString("play MediaFile");
                    }
                }
            }
        }

        public void Stop()
        {
            if (m_bOpened == true && m_bPlaying == true)
            {
                m_bPlaying = false;
                m_bPaused = false;
                m_bLoop = false;
                SendString("seek MediaFile to start");
                SendString("stop MediaFile");
            }
        }
    }
}