/*
 * MidiFile.cs
 * Copyright (c) 2009 kbinani
 *
 * This file is part of Boare.Lib.Vsq.
 *
 * Boare.Lib.Vsq is free software; you can redistribute it and/or
 * modify it under the terms of the BSD License.
 *
 * Boare.Lib.Vsq is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 */
using System;
using System.IO;
using System.Collections.Generic;

namespace Boare.Lib.Vsq {

    /// <summary>
    /// midiイベント。メタイベントは、メタイベントのデータ長をData[1]に格納せず、生のデータをDataに格納するので、注意が必要
    /// </summary>
    public struct MidiEvent : IComparable<MidiEvent> {
        public long Clock;
        public byte FirstByte;
        public byte[] Data;

        private static void writeDeltaClock( Stream stream, long number ) {
            bool[] bits = new bool[64];
            long val = 0x1;
            bits[0] = (number & val) == val;
            for ( int i = 1; i < 64; i++ ) {
                val = val << 1;
                bits[i] = (number & val) == val;
            }
            int first = 0;
            for ( int i = 63; i >= 0; i-- ) {
                if ( bits[i] ) {
                    first = i;
                    break;
                }
            }
            // 何バイト必要か？
            int bytes = first / 7 + 1;
            for ( int i = 1; i <= bytes; i++ ) {
                uint num = 0;
                uint count = 0x80;
                for ( int j = (bytes - i + 1) * 7 - 1; j >= (bytes - i + 1) * 7 - 6 - 1; j-- ) {
                    count = count >> 1;
                    if ( bits[j] ) {
                        num += count;
                    }
                }
                if ( i != bytes ) {
                    num += 0x80;
                }
                stream.WriteByte( (byte)num );
            }
        }

        private static long readDeltaClock( Stream stream ) {
            long ret = 0;
            while ( true ) {
                int i = stream.ReadByte();
                if ( i < 0 ) {
                    break;
                }
                byte d = (byte)i;
                ret = (ret << 7) | ((long)d & 0x7f);
                if ( (d & 0x80) == 0x00 ) {
                    break;
                }
            }
            return ret;
        }

        public static MidiEvent read( Stream stream, ref long last_clock, ref byte last_status_byte ) {
            long delta_clock = readDeltaClock( stream );
            last_clock += delta_clock;
            byte first_byte = (byte)stream.ReadByte();
            if ( first_byte < 0x80 ) {
                // ランニングステータスが適用される
                stream.Seek( -1, SeekOrigin.Current );
                first_byte = last_status_byte;
            } else {
                last_status_byte = first_byte;
            }
            byte ctrl = (byte)(first_byte & (byte)0xf0);
            if ( ctrl == 0x80 || ctrl == 0x90 || ctrl == 0xA0 || ctrl == 0xB0 || ctrl == 0xE0 || first_byte == 0xF2 ) {
                // 3byte使用するチャンネルメッセージ：
                //     0x8*: ノートオフ
                //     0x9*: ノートオン
                //     0xA*: ポリフォニック・キープレッシャ
                //     0xB*: コントロールチェンジ
                //     0xE*: ピッチベンドチェンジ
                // 3byte使用するシステムメッセージ
                //     0xF2: ソングポジション・ポインタ
                MidiEvent me = new MidiEvent();
                me.Clock = last_clock;
                me.FirstByte = first_byte;
                me.Data = new byte[2];
                stream.Read( me.Data, 0, 2 );
                return me;
            } else if ( ctrl == 0xC0 || ctrl == 0xD0 || first_byte == 0xF1 || first_byte == 0xF2 ) {
                // 2byte使用するチャンネルメッセージ
                //     0xC*: プログラムチェンジ
                //     0xD*: チャンネルプレッシャ
                // 2byte使用するシステムメッセージ
                //     0xF1: クォータフレーム
                //     0xF3: ソングセレクト
                MidiEvent me = new MidiEvent();
                me.Clock = last_clock;
                me.FirstByte = first_byte;
                me.Data = new byte[1];
                stream.Read( me.Data, 0, 1 );
                return me;
            } else if ( first_byte == 0xF6 ) {
                // 1byte使用するシステムメッセージ
                //     0xF6: チューンリクエスト
                //     0xF7: エンドオブエクスクルーシブ（このクラスではF0ステータスのSysExの一部として取り扱う）
                //     0xF8: タイミングクロック
                //     0xFA: スタート
                //     0xFB: コンティニュー
                //     0xFC: ストップ
                //     0xFE: アクティブセンシング
                //     0xFF: システムリセット
                MidiEvent me = new MidiEvent();
                me.Clock = last_clock;
                me.FirstByte = first_byte;
                me.Data = new byte[0];
                return me;
            } else if ( first_byte == 0xff ) {
                // メタイベント
                byte meta_event_type = (byte)stream.ReadByte();
                long meta_event_length = readDeltaClock( stream );
                MidiEvent me = new MidiEvent();
                me.Clock = last_clock;
                me.FirstByte = first_byte;
                me.Data = new byte[meta_event_length + 1];
                me.Data[0] = meta_event_type;
                stream.Read( me.Data, 1, (int)meta_event_length );
                return me;
            } else if ( first_byte == 0xf0 ) {
                // f0ステータスのSysEx
                MidiEvent me = new MidiEvent();
                me.Clock = last_clock;
                me.FirstByte = first_byte;
                long sysex_length = readDeltaClock( stream );
                me.Data = new byte[sysex_length + 1];
                stream.Read( me.Data, 0, (int)(sysex_length + 1) );
                return me;
            } else if ( first_byte == 0xf7 ) {
                // f7ステータスのSysEx
                MidiEvent me = new MidiEvent();
                me.Clock = last_clock;
                me.FirstByte = first_byte;
                long sysex_length = readDeltaClock( stream );
                me.Data = new byte[sysex_length];
                stream.Read( me.Data, 0, (int)sysex_length );
                return me;
            } else {
                throw new ApplicationException( "don't know how to process first_byte: 0x" + Convert.ToString( first_byte, 16 ) );
            }
        }

        public void writeData( Stream stream ) {
            stream.WriteByte( FirstByte );
            if ( FirstByte == 0xff ) {
                stream.WriteByte( Data[0] );
                writeDeltaClock( stream, Data.Length - 1 );
                //stream.WriteByte( (byte)(Data.Length - 1) );
                stream.Write( Data, 1, Data.Length - 1 );
            } else {
                stream.Write( Data, 0, Data.Length );
            }
        }

        public int CompareTo( MidiEvent item ) {
            return (int)(Clock - item.Clock);
        }

        public static MidiEvent generateTimeSigEvent( int clock, int numerator, int denominator ) {
            MidiEvent ret = new MidiEvent();
            ret.Clock = clock;
            ret.FirstByte = 0xff;
            byte b_numer = (byte)(Math.Log( numerator, 2 ) + 0.1);
            ret.Data = new byte[5] { 0x58, (byte)denominator, b_numer, 0x18, 0x08 };
            return ret;
        }

        public static MidiEvent generateTempoChangeEvent( int clock, int tempo ) {
            MidiEvent ret = new MidiEvent();
            ret.Clock = clock;
            ret.FirstByte = 0xff;
            byte b1 = (byte)(tempo & 0xff);
            tempo = tempo >> 8;
            byte b2 = (byte)(tempo & 0xff);
            tempo = tempo >> 8;
            byte b3 = (byte)(tempo & 0xff);
            ret.Data = new byte[4] { 0x51, b3, b2, b1 };
            return ret;
        }
    }

    public class MidiFile : IDisposable {
        private List<List<MidiEvent>> m_events;
        private ushort m_format;
        private ushort m_time_format;

        public MidiFile( string path ){
            Stream stream = new FileStream( path, FileMode.Open, FileAccess.Read );
            // ヘッダ
            byte[] byte4 = new byte[4];
            stream.Read( byte4, 0, 4 );
            if ( makeUInt32( byte4 ) != 0x4d546864 ) {
                throw new ApplicationException( "header error: MThd" );
            }

            // データ長
            stream.Read( byte4, 0, 4 );
            uint length = makeUInt32( byte4 );

            // フォーマット
            stream.Read( byte4, 0, 2 );
            m_format = makeUint16( byte4 );

            // トラック数
            int tracks = 0;
            stream.Read( byte4, 0, 2 );
            tracks = (int)makeUint16( byte4 );

            // 時間分解能
            stream.Read( byte4, 0, 2 );
            m_time_format = makeUint16( byte4 );

            // 各トラックを読込み
            m_events = new List<List<MidiEvent>>();
            for ( int track = 0; track < tracks; track++ ) {
                // ヘッダー
                stream.Read( byte4, 0, 4 );
                if ( makeUInt32( byte4 ) != 0x4d54726b ) {
                    throw new ApplicationException( "header error; MTrk" );
                }
                m_events.Add( new List<MidiEvent>() );

                // チャンクサイズ
                stream.Read( byte4, 0, 4 );
                long size = (long)makeUInt32( byte4 );
                long startpos = stream.Position;

                // チャンクの終わりまで読込み
                long clock = 0;
                byte last_status_byte = 0x00;
                while ( stream.Position < startpos + size ) {
                    MidiEvent mi = MidiEvent.read( stream, ref clock, ref last_status_byte );
                    m_events[track].Add( mi );
                }
                if ( m_time_format != 480 ) {
                    int count = m_events[track].Count;
                    for ( int i = 0; i < count; i++ ) {
                        MidiEvent mi = m_events[track][i];
                        mi.Clock = mi.Clock * 480 / m_time_format;
                        m_events[track][i] = mi;
                    }
                }
            }
            m_time_format = 480;
#if DEBUG
            string dbg = Path.Combine( Path.GetDirectoryName( path ), Path.GetFileNameWithoutExtension( path ) + ".txt" );
            using ( StreamWriter sw = new StreamWriter( dbg ) ) {
                const string format = "    {0,8} 0x{1:X4} {2,-35} 0x{3:X2} 0x{4:X2}";
                const string format0 = "    {0,8} 0x{1:X4} {2,-35} 0x{3:X2}";
                for ( int track = 1; track < m_events.Count; track++ ) {
                    sw.WriteLine( "MidiFile..ctor; track=" + track );
                    byte msb, lsb, data_msb, data_lsb;
                    msb = lsb = data_msb = data_lsb = 0x0;
                    for ( int i = 0; i < m_events[track].Count; i++ ) {
                        if ( m_events[track][i].FirstByte == 0xb0 ) {
                            switch ( m_events[track][i].Data[0] ) {
                                case 0x63:
                                    msb = m_events[track][i].Data[1];
                                    lsb = 0x0;
                                    break;
                                case 0x62:
                                    lsb = m_events[track][i].Data[1];
                                    break;
                                case 0x06:
                                    data_msb = m_events[track][i].Data[1];
                                    ushort nrpn = (ushort)(msb << 8 | lsb);
                                    string name = NRPN.getName( nrpn );
                                    if ( name == "" ) {
                                        name = "* * UNKNOWN * *";
                                        sw.WriteLine( string.Format( format0, m_events[track][i].Clock, nrpn, name, data_msb ) );
                                    } else {
                                        //if ( !NRPN.is_require_data_lsb( nrpn ) ) {
                                            sw.WriteLine( string.Format( format0, m_events[track][i].Clock, nrpn, name, data_msb ) );
                                        //}
                                    }
                                    break;
                                case 0x26:
                                    data_lsb = m_events[track][i].Data[1];
                                    ushort nrpn2 = (ushort)(msb << 8 | lsb);
                                    string name2 = NRPN.getName( nrpn2 );
                                    if ( name2 == "" ) {
                                        name2 = "* * UNKNOWN * *";
                                    }
                                    sw.WriteLine( string.Format( format, m_events[track][i].Clock, nrpn2, name2, data_msb, data_lsb ) );
                                    break;
                            }
                        }
                    }
                }
            }
#endif
            stream.Close();
        }

        /*public void Write( string path ) {
        }*/

        public List<MidiEvent> getMidiEventList( int track ) {
            if ( m_events == null ) {
                return new List<MidiEvent>();
            } else if ( 0 <= track && track < m_events.Count ) {
                return m_events[track];
            } else {
                return new List<MidiEvent>();
            }
        }

        public int getTrackCount() {
            if ( m_events == null ) {
                return 0;
            } else {
                return m_events.Count;
            }
        }

        public void Dispose() {
            Close();
        }

        public void Close() {
            if ( m_events != null ) {
                for ( int i = 0; i < m_events.Count; i++ ) {
                    m_events[i].Clear();
                }
                m_events.Clear();
            }
        }

        private static UInt32 makeUInt32( byte[] value ) {
            return (uint)((uint)((uint)((uint)(value[0] << 8) | value[1]) << 8 | value[2]) << 8 | value[3]);
        }

        private static UInt16 makeUint16( byte[] value ) {
            return (ushort)((ushort)(value[0] << 8) | value[1]);
        }

        private static long readDeltaClock( Stream stream ) {
            byte[] b;
            long ret = 0;
            while ( true ) {
                byte d = (byte)stream.ReadByte();
                ret = (ret << 7) | ((long)d & 0x7f);
                if ( (d & 0x80) == 0x00 ) {
                    break;
                }
            }
            return ret;
        }
    }

}