using System;
using System.IO;

namespace MAME.Core
{
    public unsafe class MSM5205
    {
        public struct MSM5205Voice
        {
            public vclk_delegate vclk_callback;
            public int select;
            public sound_stream stream;  /* number of stream system      */
            public int index;
            public int clock;				/* clock rate */
            public int data;               /* next adpcm data              */
            public int vclk;               /* vclk signal (external mode)  */
            public int reset;              /* reset pin signal             */
            public int prescaler;          /* prescaler selector S1 and S2 */
            public int bitwidth;           /* bit width selector -3B/4B    */
            public int signal;             /* current ADPCM signal         */
            public int step;               /* current ADPCM step           */
        };
        public delegate void vclk_delegate(int i);
        public static int[] diff_lookup;
        public static int[] index_shift = new int[8] { -1, -1, -1, -1, 2, 4, 6, 8 };
        public MSM5205Voice voice;
        public static EmuTimer.emu_timer[] timer = new EmuTimer.emu_timer[2];
        public static MSM5205[] mm1 = new MSM5205[2];
        public static void ComputeTables()
        {
            int[,] nbl2bit = new int[16, 4]
            {
                { 1, 0, 0, 0}, { 1, 0, 0, 1}, { 1, 0, 1, 0}, { 1, 0, 1, 1},
                { 1, 1, 0, 0}, { 1, 1, 0, 1}, { 1, 1, 1, 0}, { 1, 1, 1, 1},
                {-1, 0, 0, 0}, {-1, 0, 0, 1}, {-1, 0, 1, 0}, {-1, 0, 1, 1},
                {-1, 1, 0, 0}, {-1, 1, 0, 1}, {-1, 1, 1, 0}, {-1, 1, 1, 1}
            };
            int step, nib;
            diff_lookup = new int[49 * 16];
            for (step = 0; step <= 48; step++)
            {
                int stepval = (int)Math.Floor(16.0 * Math.Pow(11.0 / 10.0, (double)step));
                for (nib = 0; nib < 16; nib++)
                {
                    diff_lookup[step * 16 + nib] = nbl2bit[nib, 0] *
                        (stepval * nbl2bit[nib, 1] +
                         stepval / 2 * nbl2bit[nib, 2] +
                         stepval / 4 * nbl2bit[nib, 3] +
                         stepval / 8);
                }
            }
        }
        public void MSM5205_update(int offset, int length)
        {
            int i;
            if (voice.signal != 0)
            {
                short val = (short)(voice.signal * 16);
                for (i = 0; i < length; i++)
                {
                    voice.stream.streamoutput_Ptrs[0][offset + i] = val;
                }
            }
            else
            {
                for (i = 0; i < length; i++)
                {
                    voice.stream.streamoutput_Ptrs[0][offset + i] = 0;
                }
            }
        }
        public static void MSM5205_vclk_callback0()
        {
            int val;
            int new_signal;
            if (mm1[0].voice.vclk_callback != null)
            {
                mm1[0].voice.vclk_callback(mm1[0].voice.index);
            }
            if (mm1[0].voice.reset != 0)
            {
                new_signal = 0;
                mm1[0].voice.step = 0;
            }
            else
            {
                val = mm1[0].voice.data;
                new_signal = mm1[0].voice.signal + diff_lookup[mm1[0].voice.step * 16 + (val & 15)];
                if (new_signal > 2047)
                {
                    new_signal = 2047;
                }
                else if (new_signal < -2048)
                {
                    new_signal = -2048;
                }
                mm1[0].voice.step += index_shift[val & 7];
                if (mm1[0].voice.step > 48)
                {
                    mm1[0].voice.step = 48;
                }
                else if (mm1[0].voice.step < 0)
                {
                    mm1[0].voice.step = 0;
                }
            }
            if (mm1[0].voice.signal != new_signal)
            {
                mm1[0].voice.stream.stream_update();
                mm1[0].voice.signal = new_signal;
            }
        }
        public static void MSM5205_vclk_callback1()
        {
            int val;
            int new_signal;
            if (mm1[1].voice.vclk_callback != null)
            {
                mm1[1].voice.vclk_callback(mm1[1].voice.index);
            }
            if (mm1[1].voice.reset != 0)
            {
                new_signal = 0;
                mm1[1].voice.step = 0;
            }
            else
            {
                val = mm1[1].voice.data;
                new_signal = mm1[1].voice.signal + diff_lookup[mm1[1].voice.step * 16 + (val & 15)];
                if (new_signal > 2047)
                {
                    new_signal = 2047;
                }
                else if (new_signal < -2048)
                {
                    new_signal = -2048;
                }
                mm1[1].voice.step += index_shift[val & 7];
                if (mm1[1].voice.step > 48)
                {
                    mm1[1].voice.step = 48;
                }
                else if (mm1[1].voice.step < 0)
                {
                    mm1[1].voice.step = 0;
                }
            }
            if (mm1[1].voice.signal != new_signal)
            {
                mm1[1].voice.stream.stream_update();
                mm1[1].voice.signal = new_signal;
            }
        }
        public void msm5205_reset()
        {
            voice.data = 0;
            voice.vclk = 0;
            voice.reset = 0;
            voice.signal = 0;
            voice.step = 0;
            msm5205_playmode_w(voice.index, voice.select);
        }
        public static void msm5205_start(int sndindex, int clock, vclk_delegate vclk, int select)
        {
            //struct MSM5205Voice *voice;
            /*voice = auto_malloc(sizeof(*voice));
            memset(voice, 0, sizeof(*voice));
            sndintrf_register_token(voice);*/
            //voice.intf = config;
            mm1[sndindex] = new MSM5205();
            mm1[sndindex].voice.vclk_callback = vclk;
            mm1[sndindex].voice.select = select;
            mm1[sndindex].voice.index = sndindex;
            mm1[sndindex].voice.clock = clock;
            ComputeTables();
            /* stream system initialize */
            mm1[sndindex].voice.stream = new sound_stream(clock, 0, 1, mm1[sndindex].MSM5205_update);
            if (sndindex == 0)
            {
                timer[0] = EmuTimer.timer_alloc_common(EmuTimer.TIME_ACT.MSM5205_MSM5205_vclk_callback0, false);
            }
            else if (sndindex == 1)
            {
                timer[1] = EmuTimer.timer_alloc_common(EmuTimer.TIME_ACT.MSM5205_MSM5205_vclk_callback1, false);
            }
            mm1[sndindex].msm5205_reset();
        }
        public static void null_vclk(int i)
        {

        }
        public static void msm5205_vclk_w(int num, int vclk)
        {
            if (mm1[num].voice.prescaler != 0)
            {
                //logerror("error: msm5205_vclk_w() called with chip = %d, but VCLK selected master mode\n", num);
            }
            else
            {
                if (mm1[num].voice.vclk != vclk)
                {
                    mm1[num].voice.vclk = vclk;
                    if (vclk == 0)
                    {
                        if (num == 0)
                        {
                            MSM5205_vclk_callback0();
                        }
                        else if (num == 1)
                        {
                            MSM5205_vclk_callback1();
                        }
                    }
                }
            }
        }
        public static void msm5205_reset_w(int num, int reset)
        {
            mm1[num].voice.reset = reset;
        }
        public static void msm5205_data_w(int num, int data)
        {
            if (mm1[num].voice.bitwidth == 4)
            {
                mm1[num].voice.data = data & 0x0f;
            }
            else
            {
                mm1[num].voice.data = (data & 0x07) << 1; /* unknown */
            }
        }
        public static void msm5205_playmode_w(int num, int select)
        {
            int[] prescaler_table = new int[4] { 96, 48, 64, 0 };
            int prescaler = prescaler_table[select & 3];
            int bitwidth = ((select & 4) != 0) ? 4 : 3;
            if (mm1[num].voice.prescaler != prescaler)
            {
                mm1[num].voice.stream.stream_update();
                mm1[num].voice.prescaler = prescaler;
                if (prescaler != 0)
                {
                    Atime period = Attotime.attotime_mul(Attotime.ATTOTIME_IN_HZ(mm1[num].voice.clock), (uint)prescaler);
                    EmuTimer.timer_adjust_periodic(timer[num], period, period);
                }
                else
                {
                    EmuTimer.timer_adjust_periodic(timer[num], Attotime.ATTOTIME_NEVER, Attotime.ATTOTIME_NEVER);
                }
            }
            if (mm1[num].voice.bitwidth != bitwidth)
            {
                mm1[num].voice.stream.stream_update();
                mm1[num].voice.bitwidth = bitwidth;
            }
        }
        public void SaveStateBinary(BinaryWriter writer)
        {
            writer.Write(voice.select);
            writer.Write(voice.index);
            writer.Write(voice.clock);
            writer.Write(voice.data);
            writer.Write(voice.vclk);
            writer.Write(voice.reset);
            writer.Write(voice.prescaler);
            writer.Write(voice.bitwidth);
            writer.Write(voice.signal);
            writer.Write(voice.step);
        }
        public void LoadStateBinary(BinaryReader reader)
        {
            voice.select = reader.ReadInt32();
            voice.index = reader.ReadInt32();
            voice.clock = reader.ReadInt32();
            voice.data = reader.ReadInt32();
            voice.vclk = reader.ReadInt32();
            voice.reset = reader.ReadInt32();
            voice.prescaler = reader.ReadInt32();
            voice.bitwidth = reader.ReadInt32();
            voice.signal = reader.ReadInt32();
            voice.step = reader.ReadInt32();
        }
    }
}