#include "sound.h"
#include <SDL.h>
#include <stdio.h>
#include <stdlib.h>

#define BUFFER_SIZE 512

static const float lengths[10] = { 0.0f, 0.00390625f, 0.0078125f, 0.015625f, 0.03125f, 0.0625f, 0.125f, 0.25f, 0.5f, 1.0f };
// 9 = redona, 8 = blanca, 7 = negra, 6 = corchea, 5 = semicorchea, 4 = fusa, 3 = semifusa, 2 = garrapatea, 1 = semigarrapatea
static const Uint16 tempos[10] = { 13230, 8820, 6615, 5292, 4410, 3780, 3308, 2940, 2646, 2406 };
static const float periods[108] = { 1348.49207, 1272.80688, 1201.37, 1133.94214, 1070.29871, 1010.22772, 953.527893, 900.010376, 849.496887, 801.818176, 756.815613, 714.338745, 674.246033, 636.403564, 600.684875, 566.971069, 535.149475, 505.11377, 476.763947, 450.005249, 424.748352, 400.909088, 378.407806, 357.169373, 337.123016, 318.201782, 300.342438, 283.485535, 267.574738, 252.556885, 238.381973, 225.002625, 212.374176, 200.454544, 189.203888, 178.584702, 168.561508, 159.100876, 150.171234, 141.742767, 133.787354, 126.278458, 119.190987, 112.501305, 106.187096, 100.227272, 94.6019516, 89.2923508, 84.2807541, 79.5504379, 75.0856171, 70.8713837, 66.8936768, 63.139225, 59.5954933, 56.2506561, 53.0935478, 50.113636, 47.3009758, 44.6461754, 42.140377, 39.775219, 37.5428085, 35.4356918, 33.4468384, 31.5696125, 29.7977467, 28.1253281, 26.5467739, 25.056818, 23.650486, 22.3230877, 21.0701885, 19.8876095, 18.7714043, 17.7178459, 16.7234192, 15.7848072, 14.8988733, 14.0626631, 13.273387, 12.528409, 11.8252439, 11.1615429, 10.5350943, 9.94380569, 9.38570118, 8.85892296, 8.36171055, 7.89240265, 7.44943666, 7.03133202, 6.636693, 6.2642045, 5.91262197, 5.58077145, 5.26754713, 4.97190285, 4.69285059, 4.42946148, 4.18085527, 3.94620132, 3.72471833, 3.51566601, 3.3183465, 3.13210225, 2.95631051, 2.7903862 };

static class c_channel {
private:
	Uint8		volume{ 64 };
	Uint8		octave{ 4 };
	Uint32		tempo{ 44100 };
	float		default_length{ 0.25f };
	char		song[256];
	Uint8		pos{ 0 };

	Uint32		length{ 0 };
	Uint16		period{ 0 };
	bool		active{ false };

	void program_pipeline(const char note, const char len, const float multip = 1.0f) {
		length = (len == -1 ? default_length : lengths[len]) * multip * tempo;
		period = note == 100 ? 0 : periods[note + octave * 12];
	}

	bool parse_song() {
		while (true) {
			float multip = 1.0f;
			char note = 0;
			char param = -1;
			switch (song[pos++]) {
			case 'b': note += 2;
			case 'a': note += 2;
			case 'g': note += 2;
			case 'f': note += 1;
			case 'e': note += 2;
			case 'd': note += 2;
			case 'c':
				param = song[pos];
				if (param == '#' || param == '+') { note++; param = song[++pos]; } else if (param == '-') { note--; param = song[++pos]; }
				if (param >= 48 && param <= 57) { param -= 48; pos++; } else { param = -1; }
				if (song[pos] == '.') { multip = 1.5f; pos++; }
				program_pipeline(note, param, multip);
				return true;
			case 'r':
				param = song[pos];
				if (param >= 48 && param <= 57) { param -= 48; pos++; } else { param = -1; }
				if (song[pos] == '.') { multip = 1.5f; pos++; }
				program_pipeline(100, param, multip);
				return true;
			case 'o':
				param = song[pos];
				if (param >= 48 && param <= 57) { octave = (param - 48) % 8; pos++; }
				break;
			case '>':
				octave = (octave + 1) % 8;
				break;
			case '<':
				octave = (octave - 1) % 8;
				break;
			case 'l':
				param = song[pos];
				if (param >= 48 && param <= 57) { default_length = lengths[param - 48]; pos++; }
				else if (param == '+') { default_length *= 2; pos++; }
				else if (param == '-') { default_length /= 2; pos++; }
				break;
			case 'v':
				param = song[pos];
				if (param >= 48 && param <= 57) { volume = (param - 48) << 4; pos++; }
				break;
			case 't':
				param = song[pos];
				if (param >= 48 && param <= 57) { tempo = tempos[param - 48] * 10; pos++; }
				break;
			case '\0':
				active = false;
				return false;
			default:
				break;
			};
		}
	}

public:

	Sint8 get_datum() {
		if (!active) return 0;
		if (length == 0) if (!parse_song()) { active = false;  return 0; }
		length--;
		return period == 0 ? -128 : ((length % period) < (period >> 1) ? volume : - volume);
	}
/*	Uint8 get_datum() {
		if (!active) return 0;
		if (length == 0) if (!parse_song()) return 0;
		length--;
		return period == 0 ? 0 : ((length % period) < (period >> 1) ? 128 + volume : 128 - volume);
	}*/
	Sint8 get_noise() {
		static Sint8 last_noise;
		if (!active) return 0;
		if (length == 0) if (!parse_song()) { active = false;  return 0; }
		length--;
		if (period == 0) return -128;
		if ((length % period) < (period >> 1)) { last_noise = rand() % (volume * 2) - volume; }
		return last_noise;
	}
	void set_song(const char* melody) {
		int len = SDL_strlen(melody);
		SDL_memcpy(song, melody, len);
		song[len] = 0;
		pos = 0; volume = 64; octave = 4; tempo = 44100; default_length = 0.25f;
		active = true;
	}
	bool is_active() {
		return active;
	}
	void stop() {
		length = 0;
		period = 0;
		active = false;
	}
};

static c_channel channels[4];

static int sign(int number) { return number > 0 ? 1 : -1; }
static bool samesign(int a, int b) { return (a > 0 && b > 0) || (a < 0 && b < 0); }

static void audio_callback(void* userdata, Uint8* stream, int len) {
	Uint8 datum = 0;
	for (int i = 0; i < len; i++) {
		//for (auto& channel : channels) datum += channel.get_datum();
		Sint8 a = channels[0].get_datum();
		Sint8 b = channels[1].get_datum();
		Sint8 c = channels[2].get_datum();
		Sint8 d = channels[3].get_noise();
		//Sint16 dat = samesign(a,b) ? (a + b) - ((a * b) / sign(a)*127) : a + b;
		Sint16 dat = a + b + c + d;
		//Uint16 dat = (a + b) - ((a * b) / 256);
		if (dat > 127) dat = 127; if (dat < -128) dat = -128;
		//datum = dat; 
		datum = (dat + 128);
		*stream = datum;
		stream++;
	}
	//SDL_MixAudio(tstream, channel.pos, actual_len, SDL_MIX_MAXVOLUME);
	if (!(channels[0].is_active() || channels[1].is_active() || channels[2].is_active() || channels[3].is_active())) 
		SDL_PauseAudio(1);
}

void sound_init() {
	SDL_Init(SDL_INIT_AUDIO);

	SDL_AudioSpec spec;
	spec.freq = 22050;
	spec.format = AUDIO_U8;
	spec.channels = 1;
	spec.samples = BUFFER_SIZE;
	spec.callback = audio_callback;
	spec.userdata = NULL;

	SDL_OpenAudio(&spec, NULL);
	SDL_PauseAudio(1);
}

void sound_load(const int channel, const char* string) {
	channels[channel].set_song(string);
}

void sound_play() {
	//for (auto& channel : channels) channel.set_active();
	SDL_PauseAudio(0);
}

const bool sound_isplaying() {
	return channels[0].is_active() || channels[1].is_active() || channels[2].is_active() || channels[3].is_active(); // song_ended == 0;
}

static unsigned char in_buffer[256];
static unsigned char in_buffer_pos = 0;

#define CMD_SETMUSIC		0
#define CMD_PLAYMUSIC		1
#define CMD_STOPMUSIC		2
#define CMD_ISMUSICPLAYING	3

void sound_data_out(const unsigned char& value) {
	in_buffer[in_buffer_pos++] = value;
}

void sound_cmd_out(const unsigned char& value) {
	unsigned char channel;
	char revbuf[256]; char* prb = revbuf;
	switch (value) {
	case CMD_SETMUSIC:
		channel = in_buffer[--in_buffer_pos];
		while (in_buffer_pos > 0) { *prb++ = in_buffer[--in_buffer_pos]; } *prb = 0;
		channels[channel].set_song(revbuf);
		break;
	case CMD_PLAYMUSIC: sound_play(); break;
	case CMD_STOPMUSIC: for (auto& channel: channels) channel.stop(); SDL_PauseAudio(1); break;
	case CMD_ISMUSICPLAYING: in_buffer[0] = channels[0].is_active() || channels[1].is_active() || channels[2].is_active() || channels[3].is_active() ? 1 : 0; break;
	}
	in_buffer_pos = 0;
}

unsigned char sound_in() {
	return in_buffer[0];
}