/* This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
/** BusVoodoo I²C mode (code)
 *  @file busvoodoo_i2c.c
 *  @author King Kévin <kingkevin@cuvoodoo.info>
 *  @date 2018
 *  @note peripherals used: I2C @ref busvoodoo_i2c
 */
/* standard libraries */
#include <stdint.h> // standard integer types
#include <stdlib.h> // standard utilities
#include <string.h> // string utilities

/* STM32 (including CM3) libraries */
#include <libopencm3/stm32/i2c.h> // I2C library

/* own libraries */
#include "global.h" // board definitions
#include "print.h" // printing utilities
#include "menu.h" // menu definitions
#include "i2c_master.h" // I2C utilities
#include "busvoodoo_global.h" // BusVoodoo definitions
#include "busvoodoo_oled.h" // OLED utilities
#include "busvoodoo_i2c.h" // own definitions

/** @defgroup busvoodoo_i2c I2C peripheral to communicate with I2C devices
 *  @{
 */
#define BUSVOODOO_I2C I2C2 /**< I2C peripheral */
/** @} */

/** mode setup stage */
static enum busvoodoo_i2c_setting_t {
	BUSVOODOO_I2C_SETTING_NONE,
	BUSVOODOO_I2C_SETTING_SPEED,
	BUSVOODOO_I2C_SETTING_ADDRESSBITS,
	BUSVOODOO_I2C_SETTING_PULLUP,
	BUSVOODOO_I2C_SETTING_DONE,
} busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_NONE; /**< current mode setup stage */
/** I2C speed (in kHz) */
uint16_t busvoodoo_i2c_speed = 100;
/** I2C address bits (7 or 10) */
uint8_t busvoodoo_i2c_addressbits = 7;
/** if embedded or external pull-up resistors are use */
bool busvoodoo_i2c_embedded_pullup = true;

/** setup I2C mode
 *  @param[out] prefix terminal prompt prefix
 *  @param[in] line terminal prompt line to configure mode
 *  @return if setup is complete
 */
static bool busvoodoo_i2c_setup(char** prefix, const char* line)
{
	bool complete = false; // is the setup complete
	if (NULL==line) { // first call
		busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_NONE; // re-start configuration
	}
	switch (busvoodoo_i2c_setting) {
		case BUSVOODOO_I2C_SETTING_NONE:
			snprintf(busvoodoo_global_string, LENGTH(busvoodoo_global_string), "speed in kHz (1-400) [%u]", busvoodoo_i2c_speed);
			*prefix = busvoodoo_global_string; // ask for speed
			busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_SPEED;
			break;
		case BUSVOODOO_I2C_SETTING_SPEED:
			if (NULL==line || 0==strlen(line)) { // use default setting
				busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_ADDRESSBITS; // go to next setting
			} else { // setting provided
				uint32_t speed = atoi(line); // parse setting
				if (speed>0 && speed<=400) { // check setting
					busvoodoo_i2c_speed = speed; // remember setting
					busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_ADDRESSBITS; // go to next setting
				}
			}
			if (BUSVOODOO_I2C_SETTING_ADDRESSBITS==busvoodoo_i2c_setting) { // if next setting
				snprintf(busvoodoo_global_string, LENGTH(busvoodoo_global_string), "address size in bits (7,10) [%u]", busvoodoo_i2c_addressbits); // prepare next setting
				*prefix = busvoodoo_global_string; // display next setting
			}
			break;
		case BUSVOODOO_I2C_SETTING_ADDRESSBITS:
			if (NULL==line || 0==strlen(line)) { // use default setting
				busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_PULLUP; // go to next setting
			} else { // setting provided
				uint8_t addressbits = atoi(line); // parse setting
				if (7==addressbits || 10==addressbits) { // check setting
					busvoodoo_i2c_addressbits = addressbits; // remember setting
					busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_PULLUP; // go to next setting
				}
			}
			if (BUSVOODOO_I2C_SETTING_PULLUP==busvoodoo_i2c_setting) { // if next setting
				printf("1) open-drain, with embedded pull-up resistors (2kO)\n");
				printf("2) open-drain, with external pull-up resistors\n");
				snprintf(busvoodoo_global_string, LENGTH(busvoodoo_global_string), "drive mode (1,2) [%c]", busvoodoo_i2c_embedded_pullup ? '1' : '2'); // show drive mode
				*prefix = busvoodoo_global_string; // display next setting
			}
			break;
		case BUSVOODOO_I2C_SETTING_PULLUP:
			if (NULL==line || 0==strlen(line)) { // use default setting
				busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_DONE; // go to next setting
			} else if (1==strlen(line)) { // setting provided
				uint8_t drive = atoi(line); // parse setting
				if (1==drive || 2==drive) { // check setting
					busvoodoo_i2c_embedded_pullup = (1==drive); // remember setting
					busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_DONE; // go to next setting
				}
			}
			if (BUSVOODOO_I2C_SETTING_DONE==busvoodoo_i2c_setting) { // we have all settings, configure I2C
				i2c_master_setup(BUSVOODOO_I2C, busvoodoo_i2c_speed); // setup I2C
				if (busvoodoo_i2c_embedded_pullup) {
					busvoodoo_embedded_pullup(true); // set pull-up
					printf("use LV to set pull-up voltage\n");
				}
				led_off(); // disable LED because there is no activity
				busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_NONE; // restart settings next time
				*prefix = "I2C"; // display mode
				busvoodoo_oled_text_left(*prefix); // set mode title on OLED display
				const char* pinout_io[10] = {"GND", "5V", "3V3", "LV", "SDA", "SCL", NULL, NULL}; // HiZ mode pinout
				for (uint8_t i=0; i<LENGTH(pinout_io) && i<LENGTH(busvoodoo_global_pinout_io); i++) {
					busvoodoo_global_pinout_io[i] = pinout_io[i]; // set pin names
				}
				busvoodoo_oled_text_pinout(pinout_io, true); // set pinout on display
				busvoodoo_oled_update(); // update display to show text and pinout
				complete = true; // configuration is complete
			}
			break;
		case BUSVOODOO_I2C_SETTING_DONE: // this case is already handled before
		default: // unknown case
			busvoodoo_i2c_setting = BUSVOODOO_I2C_SETTING_NONE; // restart settings next time
			complete = false; // restart setting
			break;
	}
	return complete;
}

/** exit I2C mode
 */
static void busvoodoo_i2c_exit(void)
{
	i2c_master_release(BUSVOODOO_I2C); // release I2C peripheral
	busvoodoo_embedded_pullup(false); // disable embedded pull-ups
}

/** read from I2C */
static void busvoodoo_i2c_read(void)
{
	printf("read: ");
	busvoodoo_led_blue_pulse(BUSVOODOO_LED_PULSE); // pulse blue LED to show we read data
	uint8_t data; // to store the data read
	switch (i2c_master_read(BUSVOODOO_I2C, &data, 1)) {
		case I2C_MASTER_RC_NONE: // all went fine
			printf("0x%02x", data); // show data
			break;
		case I2C_MASTER_RC_NOT_MASTER:
			printf("slave not selected");
			break;
		case I2C_MASTER_RC_NOT_READY:
			printf("slave not ready");
			break;
		case I2C_MASTER_RC_NOT_RECEIVE:
			printf("not in receive mode");
			break;
		default:
			printf("error");
	}
	printf("\n");
}

/** write to I2C
 *  @param[in] data data to write
 */
static void busvoodoo_i2c_write(uint8_t data)
{
	printf("write 0x%02x: ", data);
	busvoodoo_led_red_pulse(BUSVOODOO_LED_PULSE); // pulse red LED to show we send data
	switch (i2c_master_write(BUSVOODOO_I2C, &data, 1)) {
		case I2C_MASTER_RC_NONE: // all went fine
			printf("ack");
			break;
		case I2C_MASTER_RC_NAK:
			printf("nack");
			break;
		case I2C_MASTER_RC_NOT_MASTER:
			printf("slave not selected");
			break;
		case I2C_MASTER_RC_NOT_READY:
			printf("slave not ready");
			break;
		case I2C_MASTER_RC_NOT_TRANSMIT:
			printf("not in transmit mode");
			break;
		default:
			printf("error");
	}
	printf("\n");
}

/** select I2C slave
 *  @param[in] slave slave I2C address
 *  @param[in] write enter read (false) or write (true) mode
 */
static void busvoodoo_i2c_select(uint16_t slave, bool write)
{
	printf("select slave ");
	if (10==busvoodoo_i2c_addressbits) {
		printf("0x%03x", slave);
	} else {
		printf("0x%02x", slave);
	}
	printf(" to %s: ", write ? "write" : "read");
	busvoodoo_led_red_pulse(BUSVOODOO_LED_PULSE); // pulse red LED to show we send the slave address
	switch (i2c_master_select_slave(BUSVOODOO_I2C, slave, 10==busvoodoo_i2c_addressbits, write)) {
		case I2C_MASTER_RC_NONE: // all went fine
			printf("selected");
			break;
		case I2C_MASTER_RC_NAK:
			printf("no such slave");
			break;
		case I2C_MASTER_RC_NOT_MASTER:
			printf("can't become master");
			break;
		case I2C_MASTER_RC_NOT_RECEIVE:
			printf("not in receive mode");
			break;
		case I2C_MASTER_RC_NOT_TRANSMIT:
			printf("not in transmit mode");
			break;
		default:
			printf("error");
	}
	printf("\n");
}

/** perform I2C action
 *  @param[in] action action to perform
 *  @param[in] repetition how many times to perform the action
 *  @param[in] perform the action (true) or just check it (false)
 *  @return true if the action has been performed, false if it is malformed
 */
static bool busvoodoo_i2c_action(const char* action, uint32_t repetition, bool perform)
{
	uint32_t length = strlen(action); // remember length since it will be used a number of times
	if (NULL==action || 0==length) { // there is nothing to do
		return true;
	}

	if (1==length && 'r'==action[0]) { // read data
		if (!perform) {
			return true;
		}
		for (uint32_t i=0; i<repetition; i++) {
			busvoodoo_i2c_read(); // read from I2C
		}
	} else if (1==length && '['==action[0]) { // select slave
		if (!perform) {
			return true;
		}
		printf("send start condition: ");
		for (uint32_t i=0; i<repetition; i++) {
			busvoodoo_led_red_pulse(BUSVOODOO_LED_PULSE); // pulse red LED to show we send start condition
			printf("%s ", I2C_MASTER_RC_NONE==i2c_master_start(BUSVOODOO_I2C) ? "sent" : "error");
		}
		printf("\n");
	} else if (1==length && ']'==action[0]) { // deselect slave
		if (!perform) {
			return true;
		}
		printf("send stop condition: ");
		for (uint32_t i=0; i<repetition; i++) {
			busvoodoo_led_red_pulse(BUSVOODOO_LED_PULSE); // pulse red LED to show we send stop condition
			printf("%s ", I2C_MASTER_RC_NONE==i2c_master_stop(BUSVOODOO_I2C) ? "sent" : "error");
		}
		printf("\n");
	} else if (1==length && 'u'==action[0]) { // sleep us
		if (!perform) {
			return true;
		}
		printf("wait for %u us\n", repetition);
		sleep_us(repetition); // sleep
	} else if (1==length && 'm'==action[0]) { // sleep ms
		if (!perform) {
			return true;
		}
		printf("wait for %u ms\n", repetition);
		sleep_ms(repetition); // sleep
	} else if ('0'==action[0]) { // send digit
		if (1==length) { // just send 0
			if (!perform) {
				return true;
			}
			for (uint32_t i=0; i<repetition; i++) {
				busvoodoo_i2c_write(0); // write to I2C
			}
		} else if ('x'==action[1] || 'b'==action[1]) { // send hex/binary
			return busvoodoo_i2c_action(action+1, repetition, perform); // just retry without leading 0
		} else if (action[1]>='0' && action[1]<='9') { // send decimal
			return busvoodoo_i2c_action(action+1, repetition, perform); // just retry without leading 0
		} else if ('r'==action[1] && 2==length) { // select slave to read
			busvoodoo_i2c_select(0, false); // select slave 0 to read
		} else if ('w'==action[1] && 2==length) { // select slave to write
			busvoodoo_i2c_select(0, true); // select slave 0 to write
		} else { // malformed action
			return false;
		}
	} else if ('x'==action[0] && length>1) { // send hexadecimal value
		for (uint32_t i=1; i<length; i++) { // check string
			if (!((action[i]>='0' && action[i]<='9') || (action[i]>='a' && action[i]<='f') || (action[i]>='A' && action[i]<='F') || ('r'==action[i] && i==length-1) || ('w'==action[i] && i==length-1))) { // check for hexadecimal character or r/w flag
				return false; // not an hexadecimal string
			}
		}
		if (!perform) {
			return true;
		}
		uint32_t value = strtol(&action[1], NULL, 16); // get hex value
		for (uint32_t i=0; i<repetition; i++) {
			if ('r'==action[length-1]) {
				busvoodoo_i2c_select(value, false); // select slave to read
			} else if ('w'==action[length-1]) {
				busvoodoo_i2c_select(value, true); // select slave to write
			} else {
				busvoodoo_i2c_write(value); // write to I2C
			}
		}
	} else if ('b'==action[0] && length>1) { // send binary value
		for (uint32_t i=1; i<length; i++) { // check string
			if (!('0'==action[i] || '1'==action[i] || ('r'==action[i] && i==length-1) || ('w'==action[i] && i==length-1))) { // check for binary character or r/w flag
				return false; // not a binary string
			}
		}
		if (!perform) {
			return true;
		}
		uint32_t value = strtol(&action[1], NULL, 2); // get binary value
		for (uint32_t i=0; i<repetition; i++) {
			if ('r'==action[length-1]) {
				busvoodoo_i2c_select(value, false); // select slave to read
			} else if ('w'==action[length-1]) {
				busvoodoo_i2c_select(value, true); // select slave to write
			} else {
				busvoodoo_i2c_write(value); // write to I2C
			}
		}
	} else if (action[0]>='1' && action[0]<='9') { // send decimal value
		for (uint32_t i=1; i<length; i++) { // check string
			if (!((action[i]>='0' && action[i]<='9') || ('w'==action[i] && i==length-1))) { // check for decimal character or r/w flag
				return false; // not a decimal string
			}
		}
		if (!perform) {
			return true;
		}
		uint32_t value = strtol(&action[0], NULL, 10); // get decimal value
		for (uint32_t i=0; i<repetition; i++) {
			if ('r'==action[length-1]) {
				busvoodoo_i2c_select(value, false); // select slave to read
			} else if ('w'==action[length-1]) {
				busvoodoo_i2c_select(value, true); // select slave to write
			} else {
				busvoodoo_i2c_write(value); // write to I2C
			}
		}
	} else if (length>=2 && ('"'==action[0] || '\''==action[0]) && (action[length-1]==action[0])) { // send ASCII character
		if (!perform) {
			return true;
		}
		for (uint32_t r=0; r<repetition; r++) {
			for (uint32_t i=1; i<length-1; i++) { // go through string
				busvoodoo_i2c_write(action[i]); // write to I2C
			}
		}
	} else { // malformed action
		return false;
	}
	return true; // all went well
}

// command handlers

/** command to perform actions
 *  @param[in] argument actions to perform
 */
static void busvoodoo_i2c_command_actions(void* argument)
{
	if (NULL==argument || 0==strlen(argument)) {
		printf("available actions (separated by space or ,):\n");
		printf("[/]\tsend start/stop conditions\n");
		printf("0x0r\tselect slave with I2C address to read\n");
		printf("0x0w\tselect slave with I2C address to write\n");
		printf("0\twrite decimal value\n");
		printf("0x0\twrite hexadecimal value\n");
		printf("0b0\twrite binary value\n");
		printf("\"a\"/'a'\twrite ASCII characters\n");
		printf("r\tread value\n");
		printf("u/m\twait 1 us/ms\n");
		printf(":n\trepeat action n times\n");
		return;
	}
	// copy argument since it will be modified
	char* copy = calloc(strlen(argument)+1, sizeof(char));
	if (!copy) {
		while (true);
	}
	strncpy(copy, argument, strlen(argument)+1);
	// verify and perform actions
	if (!busvoodoo_global_actions(copy, false, &busvoodoo_i2c_action)) { // verify actions
		printf("malformed action(s)\n");
	} else { // action are ok
		busvoodoo_global_actions(argument, true, &busvoodoo_i2c_action); // perform action
	}
	free(copy); // release memory
}

/** command to scan for slave devices
 *  @param[in] argument no argument required
 */
static void busvoodoo_i2c_command_scan(void* argument)
{
	(void)argument; // we won't use the argument
	if (!i2c_master_check_signals(BUSVOODOO_I2C)) { // ensure SCL and SDA are high
		printf("SCL or/and SDA are low. The signals need to be pulled up\n");
		if (busvoodoo_i2c_embedded_pullup) {
			printf("set pull-up voltage with LV\n");
		}
		led_blink(0.5, 0.5); // show error on LEDs
		return; // stop here
	} else {
		led_off(); // switch LEDs off
	}
	printf("scanning for I2C slaves\n");
	int16_t i2c_slaves = 0; // number of slaves found
	// check for I2C slaves by going through the address space
	for (uint16_t address=0; address < (1<<busvoodoo_i2c_addressbits); address++) {
		busvoodoo_led_red_pulse(BUSVOODOO_LED_PULSE); // pulse red LED to show transmission
		switch (i2c_master_select_slave(BUSVOODOO_I2C, address, 10==busvoodoo_i2c_addressbits, false)) { // try to select slave (includes start condition)
			case I2C_MASTER_RC_NONE: // slave found
				busvoodoo_led_red_pulse(BUSVOODOO_LED_PULSE); // pulse blue LED to show we found a slave
				printf((busvoodoo_i2c_addressbits>7) ? "0x%03x " : "0x%02x ", address); // display address
				i2c_slaves++; // increase slave count
				break;
			case I2C_MASTER_RC_START_STOP_IN_PROGESS: // I2C peripheral error
				i2c_master_reset(BUSVOODOO_I2C); // reset the I2C peripheral since it might be stuck
				printf("start condition failed\n"); // show error to user
				led_blink(0.5, 0.5); // show error on LEDs
				i2c_slaves = -2; // remember error
				break; // stop scanning
			case I2C_MASTER_RC_NOT_MASTER: // start condition failed
				i2c_master_reset(BUSVOODOO_I2C); // reset the I2C peripheral since it might be stuck
				printf("start condition failed\n"); // show error to user
				led_blink(0.5, 0.5); // show error on LEDs
				i2c_slaves = -1; // remember error
				break; // stop scanning
			case I2C_MASTER_RC_NAK: // slave did not respond
				break; // nothing to do
			default: // unexpected error
				i2c_slaves = -1; // remember error
				break;
		}
		if (i2c_slaves<0) { // error happend
			led_blink(0.5, 0.5); // show error on LEDs
			if (-1==i2c_slaves) { // just end communication
				i2c_master_stop(BUSVOODOO_I2C); // send stop condition
			} else if (-2==i2c_slaves) { // reset peripheral
				i2c_master_reset(BUSVOODOO_I2C); // reset the I2C peripheral since it might be stuck
			}
			break; // stop scan
		} else {
			if (I2C_MASTER_RC_NONE!=i2c_master_stop(BUSVOODOO_I2C)) { // stop stop condition
				i2c_master_reset(BUSVOODOO_I2C); // reset the I2C peripheral since it might be stuck
				printf("stop condition failed\n"); // show error to user
				led_blink(0.5, 0.5); // show error on LEDs
				i2c_slaves = -1; // remember error
				break;
			}
		}
	}
	if (i2c_slaves>0) {
		printf("\n");
	}
	if (i2c_slaves>=0) {
		printf("%u slave(s) found\n", i2c_slaves); // show summary
	}
}

/** I2C menu commands */ 
static const struct menu_command_t busvoodoo_i2c_commands[] = {
	{
		'a',
		"action",
		"perform protocol actions",
		MENU_ARGUMENT_STRING,
		"[actions]",
		&busvoodoo_i2c_command_actions,
	},
	{
		's',
		"scan",
		"scan for slave devices",
		MENU_ARGUMENT_NONE,
		NULL,
		&busvoodoo_i2c_command_scan,
	},
};

struct busvoodoo_mode_t busvoodoo_i2c_mode = {
	"i2c",
	"Inter-Integrated Circuit",
	&busvoodoo_i2c_setup,
	busvoodoo_i2c_commands,
	LENGTH(busvoodoo_i2c_commands),
	&busvoodoo_i2c_exit,
};
