/* 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/>.
 *
 */
/** @file main.c
@author King Kévin <kingkevin@cuvoodoo.info>
@date 2016
@brief show the time on a LED strip

The LED strip consists of 60 WS2812b LEDs.
The time is read from a DS1307 RTC module.
 */

/* standard libraries */
#include <stdint.h> // standard integer types
#include <stdio.h> // standard I/O facilities
#include <stdlib.h> // standard utilities
#include <unistd.h> // standard streams
#include <errno.h> // error number utilities

/* STM32 (including CM3) libraries */
#include <libopencm3/stm32/rcc.h> // real-time control clock library
#include <libopencm3/stm32/gpio.h> // general purpose input output library
#include <libopencm3/cm3/scb.h> // vector table definition
#include <libopencmsis/core_cm3.h> // Cortex M3 utilities
#include <libopencm3/cm3/nvic.h> // interrupt utilities
#include <libopencm3/stm32/exti.h> // external interrupt utilities

/* own libraries */
#include "global.h" // board definitions
#include "usart.h" // USART utilities
#include "usb_cdcacm.h" // USB CDC ACM utilities
#include "led_ws2812b.h" // WS2812b LEDs utilities
#include "rtc_ds1307.h" // Real Time Clock DS1307 utilities

/** @defgroup main_flags flag set in interrupts to be processed in main task
@{
 */
volatile bool button_flag = false; /**< flag set if board user button has been pressed */
/** @} */

/** the number of ticks in one second
 *  @note the other values are derived from this value @ref main_ticks
 */
#define TICKS_PER_SECOND 255
/** @defgroup main_ticks ticks per time units
 *  @note I have to use type variables because defines would be stored in signed integers, leading to an overflow it later calculations
 *  @{
 */
/** number of ticks in one second */
const uint32_t ticks_second = TICKS_PER_SECOND;
/** number of ticks in one minute */
const uint32_t ticks_minute = 60*TICKS_PER_SECOND;
/** number of ticks in one hour */
const uint32_t ticks_hour = 60*60*TICKS_PER_SECOND;
/** number of ticks in one midday (12 hours) */
const uint32_t ticks_midday = 12*60*60*TICKS_PER_SECOND;
/** @} */

/** RGB values for the WS2812b clock LEDs */
uint8_t clock_leds[WS2812B_LEDS*3] = {0};

int _write(int file, char *ptr, int len)
{
	int i;

	if (file == STDOUT_FILENO || file == STDERR_FILENO) {
		for (i = 0; i < len; i++) {
			if (ptr[i] == '\n') { // add carrier return before line feed. this is recommended for most UART terminals
				usart_putchar_nonblocking('\r'); // a second line feed doesn't break the display
				cdcacm_putchar('\r'); // a second line feed doesn't break the display
			}
			usart_putchar_nonblocking(ptr[i]); // send byte over USART
			cdcacm_putchar(ptr[i]); // send byte over USB
		}
		return i;
	}
	errno = EIO;
	return -1;
}

void led_on(void)
{
#ifdef SYSTEM_BOARD
	gpio_clear(LED_PORT, LED_PIN);
#elif MAPLE_MINI
	gpio_set(LED_PORT, LED_PIN);
#endif
}

void led_off(void)
{
#ifdef SYSTEM_BOARD
	gpio_set(LED_PORT, LED_PIN);
#elif MAPLE_MINI
	gpio_clear(LED_PORT, LED_PIN);
#endif
}

void led_toggle(void)
{
	gpio_toggle(LED_PORT, LED_PIN);
}

/** @brief switch off all clock LEDs
 *  @note LEDs need to be set separately
 */
static void clock_clear(void)
{
	// set all colors of all LEDs to 0
	for (uint16_t i=0; i<LENGTH(clock_leds); i++) {
		clock_leds[i] = 0;
	}
}

/** @brief set hours mark on clock LEDs
 *  @note LEDs need to be set separately
 */
static void clock_hours(void)
{
	for (uint8_t hour=0; hour<12; hour++) {
		uint16_t led = WS2812B_LEDS/12*hour;
		clock_leds[led*3+0] = 0xff;
		clock_leds[led*3+1] = 0xff;
		clock_leds[led*3+2] = 0xff;
	}
}

/** @brief show time on LED clock
 *  @param[in] time in ticks to show
 *  @details show hours and minutes progress as full arcs, show second position as marker. the brightness of the LED shows the progress of the unit. hours are blue, minutes green, seconds red
 *  @note LEDs need to be set separately
 */
static void clock_show_time(uint32_t time)
{
	uint32_t led_hour = (WS2812B_LEDS*(255*(uint64_t)(time%ticks_midday)))/ticks_midday; // scale to LED brightnesses for hours
	uint32_t led_minute = (WS2812B_LEDS*(255*(uint64_t)(time%ticks_hour)))/ticks_hour; // scale to LED brightnesses for minutes
	if (led_hour>=WS2812B_LEDS*255 || led_minute>=WS2812B_LEDS*255) { // a calculation error occurred
		return;
	}
	// show hours and minutes on LEDs
	if (led_hour>led_minute) {
		// show hours in blue (and clear other LEDs)
		for (uint16_t led=0; led<WS2812B_LEDS; led++) {
			clock_leds[led*3+0] = 0;
			clock_leds[led*3+1] = 0;
			if (led_hour>=0xff) { // full hours
				clock_leds[led*3+2] = 0xff;
			} else { // running hours
				clock_leds[led*3+2] = led_hour;
			}
			led_hour -= clock_leds[led*3+2];
		}
		// show minutes in green (override hours)
		for (uint16_t led=0; led<WS2812B_LEDS && led_minute>0; led++) {
			clock_leds[led*3+0] = 0;
			if (led_minute>=0xff) { // full minutes
				clock_leds[led*3+1] = 0xff;
			} else { // running minutes
				clock_leds[led*3+1] = led_minute;
			}
			led_minute -= clock_leds[led*3+1];
			clock_leds[led*3+2] = 0;
		}
	} else {
		// show minutes in green (and clear other LEDs)
		for (uint16_t led=0; led<WS2812B_LEDS; led++) {
			clock_leds[led*3+0] = 0;
			if (led_minute>=0xff) { // full minutes
				clock_leds[led*3+1] = 0xff;
			} else { // running minutes
				clock_leds[led*3+1] = led_minute;
			}
			led_minute -= clock_leds[led*3+1];
			clock_leds[led*3+2] = 0;
		}
		// show hours in blue (override minutes)
		for (uint16_t led=0; led<WS2812B_LEDS && led_hour>0; led++) {
			clock_leds[led*3+0] = 0;
			clock_leds[led*3+1] = 0;
			if (led_hour>=0xff) { // full hours
				clock_leds[led*3+2] = 0xff;
			} else { // running hours
				clock_leds[led*3+2] = led_hour;
			}
			led_hour -= clock_leds[led*3+2];
		}
	}
	// don't show seconds on full minute (better for first time setting, barely visible else)
	if (time%ticks_minute==0) {
		return;
	}
	uint16_t led_second = (WS2812B_LEDS*(time%ticks_minute))/ticks_minute; // get LED for seconds
	uint8_t brightness_second = (255*(time%ticks_second))/ticks_second; // get brightness for seconds
	// set second LED
	clock_leds[led_second*3+0] = brightness_second;
	clock_leds[led_second*3+1] = 0;
	clock_leds[led_second*3+2] = 0;
	// set previous LED
	clock_leds[((led_second-1)%WS2812B_LEDS)*3+0] = 0xff-brightness_second;
	clock_leds[((led_second-1)%WS2812B_LEDS)*3+1] = 0;
	clock_leds[((led_second-1)%WS2812B_LEDS)*3+2] = 0;
}

/** @brief set the LEDs
 *  @details set the LED colors on WS2812b LEDs
 *  @note WS2812b LED color values need to be transmitted separately
 */
static void leds_set(void)
{
	for (uint16_t i=0; i<LENGTH(clock_leds)/3; i++) {
		ws2812b_set_rgb(i,clock_leds[i*3+0],clock_leds[i*3+1],clock_leds[i*3+2]);
	}
}

/** @brief program entry point
 *  this is the firmware function started by the micro-controller
 */
int main(void)
{	
	SCB_VTOR = (uint32_t) 0x08002000; // relocate vector table because of the bootloader

	rcc_clock_setup_in_hse_8mhz_out_72mhz(); // use 8 MHz high speed external clock to generate 72 MHz internal clock
    usart_setup(); // setup USART (for printing)
    cdcacm_setup(); // setup USB CDC ACM (for printing)
    setbuf(stdout, NULL); // set standard out buffer to NULL to immediately print   
    setbuf(stderr, NULL); // set standard error buffer to NULL to immediately print

	// setup LED
	rcc_periph_clock_enable(LED_RCC); // enable clock for LED
	gpio_set_mode(LED_PORT, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, LED_PIN); // set LED pin to 'output push-pull'
	led_off(); // switch off LED to indicate setup started

	// setup button
#if defined(BUTTON_RCC) && defined(BUTTON_PORT) && defined(BUTTON_PIN) && defined(BUTTON_EXTI) && defined(BUTTON_IRQ)
	rcc_periph_clock_enable(BUTTON_RCC); // enable clock for button
	gpio_set_mode(BUTTON_PORT, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, BUTTON_PIN); // set button pin to input
	rcc_periph_clock_enable(RCC_AFIO); // enable alternate function clock for external interrupt
	exti_select_source(BUTTON_EXTI, BUTTON_PORT); // mask external interrupt of this pin only for this port
	exti_set_trigger(BUTTON_EXTI, EXTI_TRIGGER_BOTH); // trigger on both edge
	exti_enable_request(BUTTON_EXTI); // enable external interrupt
	nvic_enable_irq(BUTTON_IRQ); // enable interrupt
#endif

	// setup WS2812b LEDs
	ws2812b_setup(); // setup WS2812b LEDs
	clock_hours(); // show hour markers
	clock_clear(); // clear all LEDs
	leds_set(); // set the colors of all LEDs
	ws2812b_transmit(); // transmit set color

	// setup RTC module
	rtc_setup(); // setup RTC module

	printf("welcome to the CuVoodoo LED clock\n"); // print welcome message
	led_on(); // switch on LED to indicate setup completed

	uint32_t time = 0; // the time to display
	uint32_t current_time = 6*ticks_hour+45*ticks_minute+15*ticks_second+ticks_second/4;
	printf("setting current time\n");
	while (time<current_time) {
		if (time+ticks_hour<=current_time) { // first set hours
			time += ticks_hour; // increment hours
		} else if (time+ticks_minute<=current_time) { // second set minutes
			time += ticks_minute; // increment minutes
		} else if (time+ticks_minute<=current_time) { // third set seconds
			time += ticks_second; // increment seconds
		} else { // finally set time
			time = current_time;
		}
		clock_show_time(time); // set time (progress)
		leds_set(); // set the colors of all LEDs
		ws2812b_transmit(); // transmit set color
		// delay some time
		for (uint32_t i=0; i<400000; i++) {
			__asm__("nop");
		}
	}
	printf("it is now %02lu:%02lu:%02lu\n", time/ticks_hour, (time%ticks_hour)/ticks_minute, (time%ticks_minute)/ticks_second);

	// test RTC
	uint16_t* rtc_time = rtc_read_time();
	printf("RTC full time %04d-%02d-%02d %02d:%02d:%02d\n", rtc_time[6], rtc_time[5], rtc_time[4], rtc_time[2], rtc_time[1], rtc_time[0]);
	printf("RTC oscillator: ");
	if (rtc_oscillator_disabled()) {
		printf("disbaled\n");
	} else {
		printf("enabled\n");
	}
	//rtc_write_time(0,52,9,4,23,3,2016);
	//rtc_oscillator_enable();

	printf("input commands\n");
	bool action = false; // if an action has been performed don't go to sleep
	button_flag = false; // reset button flag
	char c; // to store received character
	bool char_flag = false; // a new character has been received
	/* toggle the LED with every transmitted character */
	while (true) { // infinite loop
		while (usart_received) { // echo every received character
			action = true; // action has been performed
			led_toggle(); // toggle LED
			c = usart_getchar(); // store receive character
			char_flag = true; // notify character has been received
		}
		while (cdcacm_received) { // echo every received character
			action = true; // action has been performed
			led_toggle(); // toggle LED
			c = usart_getchar(); // store receive character
			char_flag = true; // notify character has been received
		}
		while (char_flag) {
			char_flag = false; // reset flag
			action = true; // action has been performed
			printf("%c",c); // echo receive character

			printf("%02lu:%02lu\n", time/ticks_hour, (time%ticks_hour)/ticks_minute);
			clock_show_time(time); // set time
			time += ticks_minute; // increment time
			leds_set(); // set the colors of all LEDs
			ws2812b_transmit(); // transmit set color
		}
		while (button_flag) {
			button_flag = false; // reset flag
			action = true; // action has been performed
			led_toggle(); // toggle LED
		}
		// go to sleep if nothing had to be done, else recheck for activity
	if (action) {
			action = false;
		} else {
			__WFI(); // go to sleep
		}
	}

	return 0;
}

#if defined(BUTTON_ISR) && defined(BUTTON_EXTI)
void BUTTON_ISR(void)
{
	exti_reset_request(BUTTON_EXTI); // reset interrupt
	button_flag = true; // perform button action
}
#endif