/*
 Copyright 2013 Michael Pavone
 This file is part of BlastEm.
 BlastEm is free software distributed under the terms of the GNU General Public License version 3 or greater. See COPYING for full license text.
*/
#ifndef YM2612_H_
#define YM2612_H_

#include <stdint.h>
#include <stdio.h>

#define NUM_PART_REGS (0xB7-0x30)
#define NUM_CHANNELS 6
#define NUM_OPERATORS (4*NUM_CHANNELS)

#define YM_OPT_WAVE_LOG 1

typedef struct {
	uint32_t phase_counter;
	uint16_t envelope;
	int16_t  output;
	uint16_t total_level;
	uint16_t sustain_level;
	uint8_t  rates[4];
	uint8_t  key_scaling;
	uint8_t  multiple;
	uint8_t  detune;
	uint8_t  am;
	uint8_t  env_phase;
	uint8_t  ssg;
	uint8_t  inverted;
} ym_operator;

typedef struct {
	FILE *   logfile;
	uint16_t fnum;
	int16_t  output;
	int16_t  op1_old;
	uint8_t  block_fnum_latch;
	uint8_t  block;
	uint8_t  keycode;
	uint8_t  algorithm;
	uint8_t  feedback;
	uint8_t  ams;
	uint8_t  pms;
	uint8_t  lr;
	uint8_t  keyon;
} ym_channel;

typedef struct {
	uint16_t fnum;
	uint8_t  block;
	uint8_t  block_fnum_latch;
	uint8_t  keycode;
} ym_supp;

#define YM_PART1_START 0x21
#define YM_PART2_START 0x30
#define YM_REG_END     0xB8
#define YM_PART1_REGS (YM_REG_END-YM_PART1_START)
#define YM_PART2_REGS (YM_REG_END-YM_PART2_START)

typedef struct {
    int16_t     *audio_buffer;
    int16_t     *back_buffer;
    uint64_t    buffer_fraction;
    uint64_t    buffer_inc;
    uint32_t    clock_inc;
    uint32_t    buffer_pos;
	uint32_t    sample_rate;
    uint32_t    sample_limit;
	uint32_t    current_cycle;
	//TODO: Condense the next two fields into one
	uint32_t    write_cycle;
	uint32_t    busy_cycles;
	uint32_t    lowpass_alpha;
	ym_operator operators[NUM_OPERATORS];
	ym_channel  channels[NUM_CHANNELS];
	uint16_t    timer_a;
	uint16_t    timer_a_load;
	uint16_t    env_counter;
	ym_supp     ch3_supp[3];
	int16_t     last_left;
	int16_t     last_right;
	uint8_t     timer_b;
	uint8_t     sub_timer_b;
	uint8_t     timer_b_load;
	uint8_t     ch3_mode;
	uint8_t     current_op;
	uint8_t     current_env_op;

	uint8_t     timer_control;
	uint8_t     dac_enable;
	uint8_t     lfo_enable;
	uint8_t     lfo_freq;
	uint8_t     lfo_counter;
	uint8_t     lfo_am_step;
	uint8_t     lfo_pm_step;
	uint8_t     csm_keyon;
	uint8_t     status;
	uint8_t     selected_reg;
	uint8_t     selected_part;
	uint8_t     part1_regs[YM_PART1_REGS];
	uint8_t     part2_regs[YM_PART2_REGS];
} ym2612_context;

enum {
	REG_LFO          = 0x22,
	REG_TIMERA_HIGH  = 0x24,
	REG_TIMERA_LOW,
	REG_TIMERB,
	REG_TIME_CTRL,
	REG_KEY_ONOFF,
	REG_DAC          = 0x2A,
	REG_DAC_ENABLE,

	REG_DETUNE_MULT  = 0x30,
	REG_TOTAL_LEVEL  = 0x40,
	REG_ATTACK_KS    = 0x50,
	REG_DECAY_AM     = 0x60,
	REG_SUSTAIN_RATE = 0x70,
	REG_S_LVL_R_RATE = 0x80,
	REG_SSG_EG       = 0x90,

	REG_FNUM_LOW     = 0xA0,
	REG_BLOCK_FNUM_H = 0xA4,
	REG_FNUM_LOW_CH3 = 0xA8,
	REG_BLOCK_FN_CH3 = 0xAC,
	REG_ALG_FEEDBACK = 0xB0,
	REG_LR_AMS_PMS   = 0xB4
};

void ym_init(ym2612_context * context, uint32_t sample_rate, uint32_t master_clock, uint32_t clock_div, uint32_t sample_limit, uint32_t options, uint32_t lowpass_cutoff);
void ym_reset(ym2612_context *context);
void ym_free(ym2612_context *context);
void ym_adjust_master_clock(ym2612_context * context, uint32_t master_clock);
void ym_run(ym2612_context * context, uint32_t to_cycle);
void ym_address_write_part1(ym2612_context * context, uint8_t address);
void ym_address_write_part2(ym2612_context * context, uint8_t address);
void ym_data_write(ym2612_context * context, uint8_t value);
uint8_t ym_read_status(ym2612_context * context);
uint8_t ym_load_gst(ym2612_context * context, FILE * gstfile);
uint8_t ym_save_gst(ym2612_context * context, FILE * gstfile);
void ym_print_channel_info(ym2612_context *context, int channel);
void ym_print_timer_info(ym2612_context *context);

#endif //YM2612_H_