#include <stdint.h>
#include "systems.h"
#include <string.h>
#ifdef STM32F30X
#include <stm32f30x.h>
#include <stm32f30x_rcc.h>
#include <stm32f30x_gpio.h>
#elif defined( STM32F40_41xxx )
#include <stm32f4xx.h>
#include <stm32f4xx_rcc.h>
#include <stm32f4xx_gpio.h>
#endif
#include <core_cm4.h>
#include <core_cmFunc.h>

extern RCC_ClocksTypeDef RCC_Clocks;

//For precise timing.
volatile unsigned int *DWT_CYCCNT   = (volatile unsigned int *)0xE0001004; //address of the register
volatile unsigned int *SCB_DEMCR        = (volatile unsigned int *)0xE000EDFC; //address of the register
volatile unsigned int *DWT_CONTROL  = (volatile unsigned int *)0xE0001000; //address of the register

void send_openocd_command(int command, void *message)
{
#ifdef DEBUG
   asm("mov r0, %[cmd];"
       "mov r1, %[msg];"
       "bkpt #0xAB"
         :
         : [cmd] "r" (command), [msg] "r" (message)
         : "r0", "r1", "memory");
#endif
}


void send_text( const char * text )
{
	uint32_t m[] = { 2, (uint32_t)text, strlen(text) };
	send_openocd_command(0x05, m);
}

int __attribute__((used)) _write (int fd, const void *buf, size_t count)
{
	//uint32_t m[] = { 2, (uint32_t)buf, count };
	//send_openocd_command(0x05, m);
	int i;
	
	for (i=count; i > 0; --i) {
		while (!(USART1->SR & USART_SR_TXE));
		USART1->DR = (uint16_t)(*((char*) buf) & 0x01FF);
		buf++;
	}
	
	return count;
}

int __attribute__((used)) _read(int fd, void *buf, size_t count)
{
	int i;
	
	for (i=0; i < count; ++i) {
		while (!(USART1->SR & USART_SR_RXNE));
		*((char*) buf) = USART1->DR;
		_write(0, buf, 1);
		if (*((char*) buf) == '\r')
			break;
		buf++;
	}
	i++;
	
	return i;
}

void __attribute__((used)) * _sbrk(int incr) {
    extern char _ebss; // Defined by the linker
    static char *heap_end;
    char *prev_heap_end;


    if (heap_end == 0) {
        heap_end = &_ebss;
    }
    prev_heap_end = heap_end;

	char * stack = (char*) __get_MSP();
     if (heap_end + incr >  stack)
     {
		return  (void*)(-1);
     }

    heap_end += incr;

    return (void*) prev_heap_end;
}

void _delay_us(uint32_t us) {
	if( us ) us--; //Approximate extra overhead time.
	us *= RCC_Clocks.HCLK_Frequency/1000000;
    *SCB_DEMCR = *SCB_DEMCR | 0x01000000;
    *DWT_CYCCNT = 0; // reset the counter
    *DWT_CONTROL = *DWT_CONTROL | 1 ; // enable the counter
	while( *DWT_CYCCNT < us );
}

void ConfigureUART()
{
	GPIO_InitTypeDef GPIO_InitStruct;
	USART_InitTypeDef USART_InitStruct;

	// Enable clock for GPIOB
	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
	
	GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_USART1);
	GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_USART1);

	GPIO_InitStruct.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
	GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
	GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
	GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_UP;
	GPIO_InitStruct.GPIO_Speed = GPIO_Speed_100MHz;
	GPIO_Init(GPIOB, &GPIO_InitStruct);
	
	

	/**
	* Enable clock for USART1 peripheral
	*/
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

	/**
	* Set Baudrate to value you pass to function
	* Disable Hardware Flow control
	* Set Mode To TX and RX, so USART will work in full-duplex mode
	* Disable parity bit
	* Set 1 stop bit
	* Set Data bits to 8
	*
	* Initialize USART1
	* Activate USART1
	*/
	USART_InitStruct.USART_BaudRate = 115200;
	USART_InitStruct.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
	USART_InitStruct.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;
	USART_InitStruct.USART_Parity = USART_Parity_No;
	USART_InitStruct.USART_StopBits = USART_StopBits_1;
	USART_InitStruct.USART_WordLength = USART_WordLength_8b;
	USART_Init(USART1, &USART_InitStruct);
	USART_Cmd(USART1, ENABLE);
 
	/**
	* Enable RX interrupt
	*/
	//USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);

	/**
	* Set Channel to USART1
	* Set Channel Cmd to enable. That will enable USART1 channel in NVIC
	* Set Both priorities to 0. This means high priority
	*
	* Initialize NVIC
	*/
	/*NVIC_InitStruct.NVIC_IRQChannel = USART1_IRQn;
	NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
	NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;
	NVIC_InitStruct.NVIC_IRQChannelSubPriority = 0;
	NVIC_Init(&NVIC_InitStruct);*/
}

void ConfigureDMX()
{
	GPIO_InitTypeDef GPIO_InitStruct;
	USART_InitTypeDef USART_InitStruct;

	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

	// Set up UART GPIOs
	GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_USART2);
	GPIO_PinAFConfig(GPIOA, GPIO_PinSource3, GPIO_AF_USART2);

	GPIO_InitStruct.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3;
	GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
	GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
	GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_UP;
	GPIO_InitStruct.GPIO_Speed = GPIO_Speed_100MHz;
	GPIO_Init(GPIOB, &GPIO_InitStruct);

	// Set up control GPIOs	
	GPIO_StructInit(&GPIO_InitStruct);
	GPIO_InitStruct.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1;
	GPIO_InitStruct.GPIO_Mode = GPIO_Mode_OUT;
	GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
	GPIO_InitStruct.GPIO_Speed = GPIO_Speed_100MHz;
	GPIO_Init(GPIOB, &GPIO_InitStruct);

	// Set up UART
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);

	USART_InitStruct.USART_BaudRate = 250000;
	USART_InitStruct.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
	USART_InitStruct.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;
	USART_InitStruct.USART_Parity = USART_Parity_No;
	USART_InitStruct.USART_StopBits = USART_StopBits_2;
	USART_InitStruct.USART_WordLength = USART_WordLength_8b;
	USART_Init(USART2, &USART_InitStruct);
	USART_Cmd(USART2, ENABLE);
}

void ConfigureLED()
{
	ConfigureGPIO(LED_RED, INOUT_OUT);
	ConfigureGPIO(LED_GREEN, INOUT_OUT);
	ConfigureGPIO(LED_BLUE, INOUT_OUT);
}

uint8_t GetGPIOFromString( const char * str )
{
	int mode = 0;
	int port = -1;
	int pin = -1;
	const char * st = str;
	for( ; *st; st++ )
	{
		char c = *st;
		if( mode == 0 )
		{
			if( c >= 'A' && c <= 'F' )
			{
				port = c - 'A';
				mode = 2;
			}
			else if( c >= 'a' && c <= 'f' )
			{
				port = c - 'a';
				mode = 2;
			}
		}
		else if( mode == 2 )
		{
			if( c >= '0' && c <= '9' )
			{
				pin = 0;
				mode = 3;
			}
		}

		if( mode == 3 )
		{
			if( c >= '0' && c <= '9' )
			{
				pin = pin * 10;
				pin+= c - '0';
			}
			else
			{
				break;
			}
		}
	}

	if( port > 0 && pin > 0 && port <= 6 && pin <= 15)
	{
		return (port<<4)|pin;
	}
	else
	{
		return 0xff;
	}
}


void ConfigureGPIO( uint8_t gpio, int parameters )
{
	GPIO_InitTypeDef  GPIO_InitStructure;

	/* Enable the GPIO_LED Clock */
#ifdef STM32F30X
	RCC_AHBPeriphClockCmd( 1<<(17+(gpio>>4)), ENABLE);
#elif defined( STM32F40_41xxx )
	RCC_AHB1PeriphClockCmd( 1<<((gpio>>4)), ENABLE);
#endif

	if( parameters & DEFAULT_VALUE_FLAG )
	{
		GPIOOn( gpio );
	}
	else
	{
		GPIOOff( gpio );
	}

	/* Configure the GPIO_LED pin */
	GPIO_InitStructure.GPIO_Pin = 1<<(gpio&0xf);
	GPIO_InitStructure.GPIO_Mode = (parameters&INOUT_FLAG)?GPIO_Mode_OUT:GPIO_Mode_IN;
	GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
	GPIO_InitStructure.GPIO_PuPd = (parameters&PUPD_FLAG)?( (parameters&PUPD_UP)?GPIO_PuPd_UP:GPIO_PuPd_DOWN ):GPIO_PuPd_NOPULL;

#ifdef STM32F30X
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
#elif defined( STM32F40_41xxx )
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
#endif

	GPIO_Init(GPIOOf(gpio), &GPIO_InitStructure);
}

void JumpToBootloader(void) {
	// Many thanks to https://stm32f4-discovery.net/2017/04/tutorial-jump-system-memory-software-stm32/

	void (*SysMemBootJump)(void);
	volatile uint32_t addr = 0x1FFF0000;

	RCC_DeInit();

	// Disable and reset systick
	SysTick->CTRL = 0;
	SysTick->LOAD = 0;
	SysTick->VAL = 0;

	__disable_irq();

	// Remap system memory	
	SYSCFG->MEMRMP = 0x01;

	SysMemBootJump = (void (*)(void)) (*((uint32_t *)(addr + 4)));

	// Set main stack pointer
	__set_MSP(*(uint32_t *)addr);

	// Jump
	SysMemBootJump();
}