/* 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/>.
 *
 */
/** STM32F1 application example
 *  @file application.c
 *  @author King Kévin <kingkevin@cuvoodoo.info>
 *  @date 2016-2018
 */

/* standard libraries */
#include <stdint.h> // standard integer types
#include <stdlib.h> // standard utilities
#include <string.h> // string utilities

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

/* own libraries */
#include "global.h" // board definitions
#include "print.h" // printing utilities
#include "uart.h" // USART utilities
#include "usb_cdcacm.h" // USB CDC ACM utilities
#include "terminal.h" // handle the terminal interface
#include "menu.h" // menu utilities

#define WATCHDOG_PERIOD 10000 /**< watchdog period in ms */

/** @defgroup main_flags flag set in interrupts to be processed in main task
 *  @{
 */
volatile bool rtc_internal_tick_flag = false; /**< flag set when internal RTC ticked */
/** @} */

size_t putc(char c)
{
	size_t length = 0; // number of characters printed
	static char last_c = 0; // to remember on which character we last sent
	if ('\n' == c) { // send carriage return (CR) + line feed (LF) newline for each LF
		if ('\r' != last_c) { // CR has not already been sent
			uart_putchar_nonblocking('\r'); // send CR over USART
			usb_cdcacm_putchar('\r'); // send CR over USB
			length++; // remember we printed 1 character
		}
	}
	uart_putchar_nonblocking(c); // send byte over USART
	usb_cdcacm_putchar(c); // send byte over USB
	length++; // remember we printed 1 character
	last_c = c; // remember last character
	return length; // return number of characters printed   
}

/** display available commands
 *  @param[in] argument no argument required
 */
static void command_help(void* argument);

/** show software and hardware version
 *  @param[in] argument no argument required
 */
static void command_version(void* argument);

/** show uptime
 *  @param[in] argument no argument required
 */
static void command_uptime(void* argument);

/** reset board
 *  @param[in] argument no argument required
 */
static void command_reset(void* argument);

/** switch to DFU bootloader
 *  @param[in] argument no argument required
 */
static void command_bootloader(void* argument);

/** list of all supported commands */
static const struct menu_command_t menu_commands[] = {
	{
		.shortcut = 'h',
		.name = "help",
		.command_description = "display help",
		.argument = MENU_ARGUMENT_NONE,
		.argument_description = NULL,
		.command_handler = &command_help,
	},
	{
		.shortcut = 'v',
		.name = "version",
		.command_description = "show software and hardware version",
		.argument = MENU_ARGUMENT_NONE,
		.argument_description = NULL,
		.command_handler = &command_version,
	},
	{
		.shortcut = 'u',
		.name = "uptime",
		.command_description = "show uptime",
		.argument = MENU_ARGUMENT_NONE,
		.argument_description = NULL,
		.command_handler = &command_uptime,
	},
	{
		.shortcut = 'r',
		.name = "reset",
		.command_description = "reset board",
		.argument = MENU_ARGUMENT_NONE,
		.argument_description = NULL,
		.command_handler = &command_reset,
	},
	{
		.shortcut = 'b',
		.name = "bootloader",
		.command_description = "reboot into DFU bootloader",
		.argument = MENU_ARGUMENT_NONE,
		.argument_description = NULL,
		.command_handler = &command_bootloader,
	},
};

static void command_help(void* argument)
{
	(void)argument; // we won't use the argument
	printf("available commands:\n");
	menu_print_commands(menu_commands, LENGTH(menu_commands)); // print global commands
}

static void command_version(void* argument)
{
	(void)argument; // we won't use the argument
	printf("firmware date: %04u-%02u-%02u\n", BUILD_YEAR, BUILD_MONTH, BUILD_DAY); // show firmware build date
	// get device identifier (DEV_ID)
	// 0x412: low-density, 16-32 kB flash
	// 0x410: medium-density, 64-128 kB flash
	// 0x414: high-density, 256-512 kB flash
	// 0x430: XL-density, 768-1024 kB flash
	// 0x418: connectivity
	printf("device family: ");
	switch (DBGMCU_IDCODE&DBGMCU_IDCODE_DEV_ID_MASK) {
		case 0: // this is a known issue document in STM32F10xxC/D/E Errata sheet, without workaround
			printf("unreadable\n");
			break;
		case 0x412:
			printf("low-density\n");
			break;
		case 0x410:
			printf("medium-density\n");
			break;
		case 0x414:
			printf("high-density\n");
			break;
		case 0x430:
			printf("XL-density\n");
			break;
		case 0x418:
			printf("connectivity\n");
			break;
		default:
			printf("unknown\n");
			break;
	}
	// show flash size
	printf("flash size: ");
	if (0xffff==DESIG_FLASH_SIZE) {
		printf("unknown (probably a defective micro-controller\n");
	} else {
		printf("%u KB\n", DESIG_FLASH_SIZE);
	}
	// display device identity
	printf("device id: %08x%08x%08x\n", DESIG_UNIQUE_ID0, DESIG_UNIQUE_ID1, DESIG_UNIQUE_ID2);
}

static void command_uptime(void* argument)
{
	(void)argument; // we won't use the argument
	uint32_t uptime = rtc_get_counter_val(); // get time from internal RTC
	printf("uptime: %u.%02u:%02u:%02u\n", uptime/(24*60*60), (uptime/(60*60))%24, (uptime/60)%60, uptime%60);
}

static void command_reset(void* argument)
{
	(void)argument; // we won't use the argument
	scb_reset_system(); // reset device
	while (true); // wait for the reset to happen
}

static void command_bootloader(void* argument)
{
	(void)argument; // we won't use the argument
	RCC_CSR |= RCC_CSR_RMVF; // clear reset flags
	scb_reset_core(); // reset core (the bootloader will interpret it as starting into DFU)
	while (true); // wait for the reset to happen
}

/** process user command
 *  @param[in] str user command string (\0 ended)
 */
static void process_command(char* str)
{
	// ensure actions are available
	if (NULL==menu_commands || 0==LENGTH(menu_commands)) {
		return;
	}
	// don't handle empty lines
	if (!str || 0==strlen(str)) {
		return;
	}
	bool command_handled = false;
	if (!command_handled) {
		command_handled = menu_handle_command(str, menu_commands, LENGTH(menu_commands)); // try if this is not a global command
	}
	if (!command_handled) {
		printf("command not recognized. enter help to list commands\n");
	}
}

/** program entry point
 *  this is the firmware function started by the micro-controller
 */
void main(void);
void main(void)
{
	rcc_clock_setup_in_hse_8mhz_out_72mhz(); // use 8 MHz high speed external clock to generate 72 MHz internal clock

#if DEBUG
	// enable functionalities for easier debug
	DBGMCU_CR |= DBGMCU_CR_IWDG_STOP; // stop independent watchdog counter when code is halted
	DBGMCU_CR |= DBGMCU_CR_WWDG_STOP; // stop window watchdog counter when code is halted
	DBGMCU_CR |= DBGMCU_CR_STANDBY; // allow debug also in standby mode (keep digital part and clock powered)
	DBGMCU_CR |= DBGMCU_CR_STOP; // allow debug also in stop mode (keep clock powered)
	DBGMCU_CR |= DBGMCU_CR_SLEEP; // allow debug also in sleep mode (keep clock powered)
#else
	// setup watchdog to reset in case we get stuck (i.e. when an error occurred)
	iwdg_set_period_ms(WATCHDOG_PERIOD); // set independent watchdog period
	iwdg_start(); // start independent watchdog
#endif

	board_setup(); // setup board
	uart_setup(); // setup USART (for printing)
	usb_cdcacm_setup(); // setup USB CDC ACM (for printing)
	printf("\nwelcome to the CuVoodoo STM32F1 example application\n"); // print welcome message

#if !(DEBUG)
	// show watchdog information
	printf("setup watchdog: %.2fs",WATCHDOG_PERIOD/1000.0);
	if (FLASH_OBR&FLASH_OBR_OPTERR) {
		printf(" (option bytes not set in flash: software wachtdog used, not automatically started at reset)\n");
	} else if (FLASH_OBR&FLASH_OBR_WDG_SW) {
		printf(" (software wachtdog used, not automatically started at reset)\n");
	} else {
		printf(" (hardware wachtdog used, automatically started at reset)\n");
	}
#endif

	// setup RTC
	printf("setup internal RTC: ");
	rtc_auto_awake(RCC_LSE, 32768-1); // ensure internal RTC is on, uses the 32.678 kHz LSE, and the prescale is set to our tick speed, else update backup registers accordingly (power off the micro-controller for the change to take effect)
	rtc_interrupt_enable(RTC_SEC); // enable RTC interrupt on "seconds"
	nvic_enable_irq(NVIC_RTC_IRQ); // allow the RTC to interrupt
	printf("OK\n");

	// setup terminal
	terminal_prefix = ""; // set default prefix
	terminal_process = &process_command; // set central function to process commands
	terminal_setup(); // start terminal

	// start main loop
	bool action = false; // if an action has been performed don't go to sleep
	button_flag = false; // reset button flag
	while (true) { // infinite loop
		iwdg_reset(); // kick the dog
		while (user_input_available) { // user input is available
			action = true; // action has been performed
			led_toggle(); // toggle LED
			char c = user_input_get(); // store receive character
			terminal_send(c); // send received character to terminal
		}
		while (button_flag) { // user pressed button
			action = true; // action has been performed
			printf("button pressed\n");
			led_toggle(); // toggle LED
			for (uint32_t i=0; i<1000000; i++) { // wait a bit to remove noise and double trigger
				__asm__("nop");
			}
			button_flag = false; // reset flag
		}
		while (rtc_internal_tick_flag) { // the internal RTC ticked
			rtc_internal_tick_flag = false; // reset flag
			action = true; // action has been performed
#if !defined(BLUE_PILL) // on the blue pill the LED is close to the 32.768 kHz oscillator and heavily influences it
			led_toggle(); // toggle LED (good to indicate if main function is stuck)
#endif
		}
		if (action) { // go to sleep if nothing had to be done, else recheck for activity
			action = false;
		} else {
			__WFI(); // go to sleep
		}
	} // main loop
}

/** @brief interrupt service routine called when tick passed on RTC */
void rtc_isr(void)
{
	rtc_clear_flag(RTC_SEC); // clear flag
	rtc_internal_tick_flag = true; // notify to show new time
}