#include "i2c.h"

#include "rcc.h"
#include "stm32.h"
#include "thread.h"

I2C* I2C::self;

template <>
void interrupt<Interrupt::I2C1_EV>() {
	I2C::self->irq_ev();
}

template <>
void interrupt<Interrupt::I2C1_ER>() {
	I2C::self->irq_er();
}

void I2C::irq_ev() {
	uint32_t sr1 = I2C1.SR1;
	I2C1.SR2;
	
	// EV5, SB = 1: Start condition sent.
	if(sr1 & 0x01) {
		// Send address.
		I2C1.DR = (addr << 1) | (writing ? 0 : 1);
	}
	
	// EV6, ADDR = 1: Address sent.
	if(sr1 & 0x02) {
		if(writing) {
			I2C1.DR = *write_p++;
			writing--;
		} else {
			if(reading > 1) {
				I2C1.CR1 |= 0x400; // Set ACK.
			} else {
				I2C1.CR1 |= 0x200; // Set STOP.
			}
		}
	}
	
	// EV7, RxNE = 1: Receive buffer not empty.
	if(sr1 & 0x40) {
		*read_p++ = I2C1.DR;
		reading--;
		
		if(reading == 1) {
			// Unset ACK, set STOP.
			I2C1.CR1 = (I2C1.CR1 & ~0x400) | 0x200;
		}
		
		if(reading == 0) {
			busy = 0;
		}
	}
	
	//I2C1.CR1 &= ~0x400;
	
	// EV8, TxE = 1, BTF = 0: Transmit buffer empty, still writing.
	if(sr1 & 0x80 && !(sr1 & 0x04)) {
		if(writing) {
			// Send data.
			I2C1.DR = *write_p++;
			writing--;
		} else {
			// All data sent.
			
			if(reading) {
				// Send repeat start.
				I2C1.CR1 |= 0x100;
			} else {
				// Send stop.
				I2C1.CR1 |= 0x200;
				busy = 0;
			}
		}
	}
}

void I2C::irq_er() {
	handle_error();
}

void I2C::handle_error() {
	I2C1.SR1;
	I2C1.SR2;
	
	//while(1);
	I2C1.CR1 |= 0x200;
	busy = 0;
}

void I2C::enable() {
	RCC.enable(RCC.I2C1);
	asm volatile("nop");
	
	I2C1.CR1 = 0x8000;
	I2C1.CR1 = 0;
	
	I2C1.CR2 = 0x700 | 36;
	I2C1.TRISE = 37;
	I2C1.CCR = 180;
	
	Interrupt::enable(Interrupt::I2C1_EV);
	Interrupt::enable(Interrupt::I2C1_ER);
	
	I2C1.CR1 = 1;
}

void I2C::write_reg(uint8_t addr_, uint8_t reg, uint8_t data) {
	addr = addr_;
	writing = 2;
	reading = 0;
	volatile uint8_t buf[] = {reg, data};
	write_p = buf;
	busy = 1;
	
	I2C1.CR1 |= 0x100;
	
	while(busy) {
		Thread::yield();
	}
	
	/*
	while(!(I2C1.SR1 & 0x01)); // Wait for SB.
	
	I2C1.DR = (addr << 1) | 0;
	while (!(I2C1.SR1 & 0x02)); // Wait for ADDR.
	I2C1.SR2;
	
	I2C1.DR = reg;
	while (!(I2C1.SR1 & 0x80)); // Wait for TxE.
	
	I2C1.DR = data;
	while (!(I2C1.SR1 & 0x04)); // Wait for BTF.
	
	I2C1.CR1 |= 0x200;*/
}

void I2C::read_reg(uint8_t addr_, uint8_t reg, uint8_t len, uint8_t* buf) {
	addr = addr_;
	writing = 1;
	reading = len;
	write_p = &reg;
	read_p = buf;
	busy = 1;
	
	I2C1.CR1 |= 0x100;
	
	while(busy) {
		Thread::yield();
	}
	
	/*
	I2C1.CR1 |= 0x100;
	while(!(I2C1.SR1 & 0x01)); // Wait for SB.
	
	I2C1.DR = (addr << 1) | 0;
	while (!(I2C1.SR1 & 0x02)); // Wait for ADDR.
	I2C1.SR2;
	
	I2C1.DR = reg;
	while (!(I2C1.SR1 & 0x80)); // Wait for TxE.
	
	I2C1.CR1 |= 0x100;
	while(!(I2C1.SR1 & 0x01)); // Wait for SB.
	
	I2C1.DR = (addr << 1) | 1;
	while (!(I2C1.SR1 & 0x02)); // Wait for ADDR.
	I2C1.SR2;
	
	I2C1.CR1 |= 0x400; // Set ACK.
	
	while(len) {
		if(len == 3) {
			while (!(I2C1.SR1 & 0x04)); // Wait for BTF.
			
			I2C1.CR1 &= ~0x400; // Clear ACK.
			*buf++ = I2C1.DR;
			len--;
			
			I2C1.CR1 |= 0x200; // Set STOP.
			*buf++ = I2C1.DR;
			len--;
			
		} else {
			while (!(I2C1.SR1 & 0x40)); // Wait for RxNE.
			
			*buf++ = I2C1.DR;
			len--;
		}
	}
	*/
}