/**
 * AY/YM emulator include file
 */

#ifndef _AYEMU_ay8912_h
#define _AYEMU_ay8912_h

#include <stddef.h>

BEGIN_C_DECLS

// TODO: ayemu_ay_t - hide all private data, allocate it in init function.

typedef unsigned char ayemu_ay_reg_frame_t[14];



/** Types of stereo.
    The codes of stereo types used for generage sound. */
typedef enum
{
  AYEMU_MONO = 0,
  AYEMU_ABC,
  AYEMU_ACB,
  AYEMU_BAC,
  AYEMU_BCA,
  AYEMU_CAB,
  AYEMU_CBA,
  AYEMU_STEREO_CUSTOM = 255
} ayemu_stereo_t;

/** Sound chip type.
    Constant for identify used chip for emulation */
typedef enum {
  AYEMU_AY,			/**< default AY chip (lion17 for now) */
  AYEMU_YM,			/**< default YM chip (lion17 for now) */
  AYEMU_AY_LION17,		/**< emulate AY with Lion17 table */
  AYEMU_YM_LION17,		/**< emulate YM with Lion17 table */
  AYEMU_AY_KAY,			/**< emulate AY with HACKER KAY table */
  AYEMU_YM_KAY,			/**< emulate YM with HACKER KAY table */
  AYEMU_AY_LOG,			/**< emulate AY with logariphmic table */
  AYEMU_YM_LOG,			/**< emulate YM with logariphmic table */
  AYEMU_AY_CUSTOM,		/**< use AY with custom table. */
  AYEMU_YM_CUSTOM		/**< use YM with custom table. */
} ayemu_chip_t;

/** parsed by #ayemu_set_regs() AY registers data \internal */
typedef struct
{
  int tone_a;           /**< R0, R1 */
  int tone_b;		/**< R2, R3 */	
  int tone_c;		/**< R4, R5 */
  int noise;		/**< R6 */
  int R7_tone_a;	/**< R7 bit 0 */
  int R7_tone_b;	/**< R7 bit 1 */
  int R7_tone_c;	/**< R7 bit 2 */
  int R7_noise_a;	/**< R7 bit 3 */
  int R7_noise_b;	/**< R7 bit 4 */
  int R7_noise_c;	/**< R7 bit 5 */
  int vol_a;		/**< R8 bits 3-0 */
  int vol_b;		/**< R9 bits 3-0 */
  int vol_c;		/**< R10 bits 3-0 */
  int env_a;		/**< R8 bit 4 */
  int env_b;		/**< R9 bit 4 */
  int env_c;		/**< R10 bit 4 */
  int env_freq;		/**< R11, R12 */
  int env_style;	/**< R13 */
}
ayemu_regdata_t;


/** Output sound format \internal */
typedef struct
{
  int freq;			/**< sound freq */
  int channels;			/**< channels (1-mono, 2-stereo) */
  int bpc;			/**< bits (8 or 16) */
}
ayemu_sndfmt_t;

/**
 * \defgroup libayemu Functions for emulate AY/YM chip
 */
/*@{*/

/** Data structure for sound chip emulation \internal
 * 
 */
typedef struct
{
  /* emulator settings */
  int table[32];		/**< table of volumes for chip */
  ayemu_chip_t type;		/**< general chip type (\b AYEMU_AY or \b AYEMU_YM) */
  int ChipFreq;			/**< chip emulator frequency */
  int eq[6];			/**< volumes for channels.
				   Array contains 6 elements: 
				   A left, A right, B left, B right, C left and C right;
				   range -100...100 */
  ayemu_regdata_t regs;		/**< parsed registers data */
  ayemu_sndfmt_t sndfmt;	/**< output sound format */

  /* flags */
  int magic;			/**< structure initialized flag */
  int default_chip_flag;	/**< =1 after init, resets in #ayemu_set_chip_type() */
  int default_stereo_flag;	/**< =1 after init, resets in #ayemu_set_stereo() */
  int default_sound_format_flag; /**< =1 after init, resets in #ayemu_set_sound_format() */
  int dirty;			/**< dirty flag. Sets if any emulator properties changed */

  int bit_a;			/**< state of channel A generator */
  int bit_b;			/**< state of channel B generator */
  int bit_c;			/**< state of channel C generator */
  int bit_n;			/**< current generator state */
  int cnt_a;			/**< back counter of A */
  int cnt_b;			/**< back counter of B */
  int cnt_c;			/**< back counter of C */
  int cnt_n;			/**< back counter of noise generator */
  int cnt_e;			/**< back counter of envelop generator */
  int ChipTacts_per_outcount;   /**< chip's counts per one sound signal count */
  int Amp_Global;		/**< scale factor for amplitude */
  int vols[6][32];              /**< stereo type (channel volumes) and chip table.
				   This cache calculated by #table and #eq  */
  int EnvNum;		        /**< number of current envilopment (0...15) */
  int env_pos;			/**< current position in envelop (0...127) */
  int Cur_Seed;		        /**< random numbers counter */
}
ayemu_ay_t;

EXTERN void
ayemu_init(ayemu_ay_t *ay);

EXTERN void
ayemu_reset(ayemu_ay_t *ay);

EXTERN int 
ayemu_set_chip_type(ayemu_ay_t *ay, ayemu_chip_t chip, int *custom_table);

EXTERN void
ayemu_set_chip_freq(ayemu_ay_t *ay, int chipfreq);

EXTERN int
ayemu_set_stereo(ayemu_ay_t *ay, ayemu_stereo_t stereo, int *custom_eq);

EXTERN int
ayemu_set_sound_format (ayemu_ay_t *ay, int freq, int chans, int bits);

EXTERN void 
ayemu_set_regs (ayemu_ay_t *ay, ayemu_ay_reg_frame_t regs);

EXTERN void*
ayemu_gen_sound (ayemu_ay_t *ay, void *buf, size_t bufsize);

/*@}*/

END_C_DECLS

#endif