// Commander X16 Emulator

// Copyright (c) 2021 Michael Steil

// All rights reserved. License: 2-clause BSD

#ifndef _I2C_H_

#define _I2C_H_

#include <stdint.h>

#include <stdbool.h>

#ifdef __cplusplus

extern "C" {

#endif

#define I2C_DATA_MASK 1

#define I2C_CLK_MASK 2

typedef struct {

	int clk_in;

	int data_in;

	int data_out;

} i2c_port_t;

extern i2c_port_t i2c_port;

void i2c_reset_state();

void i2c_step();

void i2c_kbd_buffer_add(uint8_t value);

uint8_t i2c_kbd_buffer_next();

void i2c_kbd_buffer_flush();

uint8_t i2c_kbd_buffer_count();

void i2c_mse_buffer_add(uint8_t value);

uint8_t i2c_mse_buffer_next();

void i2c_mse_buffer_flush();

uint8_t i2c_mse_buffer_count();

// fake mouse

void mouse_button_down(int num);

void mouse_button_up(int num);

void mouse_move(int x, int y);

uint8_t mouse_read(uint8_t reg);

void mouse_send_state(void);

void mouse_set_wheel(int8_t y);

uint8_t mouse_get_device_id();

void mouse_set_device_id(uint8_t d);

// ─── Debugger accessor ───────────────────────────────────────────────────────

// Side-effect-free snapshot of I2C bus state. Safe to call every frame from

// the debugger while the emulation is running.

//

// Known device addresses: 0x42 = SMC, 0x6F = RTC.

// device_name is a short static string label ("SMC", "RTC", or "" for unknown).

// Session counters (transactions_started etc.) are cumulative since boot and

// are never decremented.

typedef struct {

	int      state;                  // bus state machine: -1=STOP, 0=START, 1-8=bit index

	bool     read_mode;              // current byte is being read from the device

	uint8_t  value;                  // byte currently being assembled/shifted

	int      count;                  // byte count within the current transaction

	uint8_t  device;                 // I2C device address for the current transaction

	char     device_name[8];         // human-readable name for the device address

	int      clk_in;                 // i2c_port.clk_in

	int      data_in;                // i2c_port.data_in

	int      data_out;               // i2c_port.data_out

	uint32_t transactions_started;   // cumulative START conditions seen

	uint32_t transactions_completed; // cumulative STOP conditions seen

	uint32_t bytes_read;             // cumulative bytes read from devices

	uint32_t bytes_written;          // cumulative bytes written to devices

	uint8_t  kbd_fill;               // keyboard ring buffer occupancy

	uint8_t  mse_fill;               // mouse ring buffer occupancy

} i2c_debug_state_t;

void i2c_debug_get_state(i2c_debug_state_t *out);

#ifdef __cplusplus

}

#endif

#endif