#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/adc.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/dma.h>
#include <libopencm3/stm32/timer.h>
#include <libopencm3/cm3/nvic.h>
#include <libopencm3/cm3/systick.h>

#include <fxp.h>
#include <fxp_basic.h>

#include "lcd.h"
#include "debug.h"

#define CONV_PWM_MAX 960

#define TIM_CH_CONV      TIM_OC1
#define TIM_CH_BOOTSTRAP TIM_OC2

volatile int wait_frame = 1;

#define ADC_NUM_CHANNELS 3
volatile uint16_t adc_values[ADC_NUM_CHANNELS];

static void init_gpio(void)
{
	// Set up UART TX on PB6 for debugging
	gpio_mode_setup(GPIOB, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO6);
	gpio_set_af(GPIOB, GPIO_AF0, GPIO6);

	// GPIO for converter switch
	// FIXME: AF
	gpio_mode_setup(GPIOA, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO8);
	gpio_clear(GPIOA, GPIO8);

	// GPIO for bootstrap pulse
	// FIXME: AF
	gpio_mode_setup(GPIOA, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO9);
	gpio_clear(GPIOA, GPIO9);

	// GPIO for load activation
	gpio_mode_setup(GPIOA, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO15);
	gpio_set(GPIOA, GPIO15);
}

static void init_clock(void)
{
	/* Set STM32 to 48 MHz. */
	// Relevant for Timers
	//rcc_clock_setup_in_hse_8mhz_out_48mhz();
	rcc_clock_setup_in_hsi_out_48mhz();

	// enable GPIO clocks:
	// Port A is needed for the Display and more
	rcc_periph_clock_enable(RCC_GPIOA);

	// Port B is needed for debugging
	rcc_periph_clock_enable(RCC_GPIOB);

	// enable TIM3 for scheduling
	rcc_periph_clock_enable(RCC_TIM3);

	// enable TIM1 for PWM generation
	rcc_periph_clock_enable(RCC_TIM1);

	// enable ADC1 clock
	rcc_periph_clock_enable(RCC_ADC1);

	// enable DMA
	rcc_periph_clock_enable(RCC_DMA);
}

static void init_timer(void)
{
	// *** TIM1 ***
	// Configure channels 1 and 2 for PWM (-> Pins PA8, PA9)
	// Ch1 = Buck converter switch, Ch2 = bootstrap pulse
	timer_reset(TIM1);

	timer_set_mode(TIM1, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);

	// set up PWM channels
	timer_set_oc_mode(TIM1, TIM_CH_CONV, TIM_OCM_PWM1);
	timer_enable_oc_output(TIM1, TIM_CH_CONV);
	timer_enable_oc_preload(TIM1, TIM_CH_CONV);
	timer_set_oc_polarity_high(TIM1, TIM_CH_CONV);

	timer_set_oc_mode(TIM1, TIM_CH_BOOTSTRAP, TIM_OCM_PWM1);
	timer_enable_oc_output(TIM1, TIM_CH_BOOTSTRAP);
	timer_enable_oc_preload(TIM1, TIM_CH_BOOTSTRAP);
	timer_set_oc_polarity_low(TIM1, TIM_CH_BOOTSTRAP);

	timer_set_oc_value(TIM1, TIM_CH_CONV, 0); // no PWM by default
	timer_set_oc_value(TIM1, TIM_CH_BOOTSTRAP, 0); // no PWM by default

	// wanted: 50 kHz / 20 us period
	// system clock: 48 MHz
	// => 960 clock cycles / period = CONV_PWM_MAX

	// prescaler
	timer_set_prescaler(TIM1, 0); // Timer runs at system clock

	// auto-reload value
	timer_set_period(TIM1, CONV_PWM_MAX - 1);

	// enable update interrupt (triggered on timer restart)
	//timer_enable_irq(TIM1, TIM_DIER_UIE);

	// *** TIM3 ***
	// used for the 1-millisecond system tick
	timer_reset(TIM3);

	timer_set_mode(TIM3, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);

	// prescaler
	timer_set_prescaler(TIM3, 47); // -> 1 us counting at 48 MHz

	// auto-reload value
	timer_set_period(TIM3, 999); // -> update interrupt every 1 ms

	// enable update interrupt (triggered on timer restart)
	timer_enable_irq(TIM3, TIM_DIER_UIE);
	nvic_enable_irq(NVIC_TIM3_IRQ);

	// Start all the timers!
	timer_enable_counter(TIM3);
	timer_enable_counter(TIM1);

}

static void init_adc(void)
{
	uint8_t channels[ADC_NUM_CHANNELS] = {
		ADC_CHANNEL0, // VInSense
		ADC_CHANNEL1, // VOutSense
		ADC_CHANNEL2  // CurrentSense
	};

	adc_power_off(ADC1);

	// configure ADC
	//adc_enable_scan_mode(ADC1);
	adc_set_single_conversion_mode(ADC1);
	adc_set_resolution(ADC1, ADC_RESOLUTION_12BIT);
	adc_set_sample_time_on_all_channels(ADC1, ADC_SMPR_SMP_071DOT5);
	adc_disable_external_trigger_regular(ADC1);
	adc_set_right_aligned(ADC1);
	adc_set_regular_sequence(ADC1, ADC_NUM_CHANNELS, channels);

	// configure DMA for ADC

	//nvic_enable_irq(NVIC_DMA1_STREAM5_IRQ);
	dma_channel_reset(DMA1, DMA_CHANNEL1);
	dma_set_priority(DMA1, DMA_CHANNEL1, DMA_CCR_PL_LOW);
	dma_set_memory_size(DMA1, DMA_CHANNEL1, DMA_CCR_MSIZE_16BIT);
	dma_set_peripheral_size(DMA1, DMA_CHANNEL1, DMA_CCR_PSIZE_16BIT);
	dma_enable_memory_increment_mode(DMA1, DMA_CHANNEL1);
	dma_enable_circular_mode(DMA1, DMA_CHANNEL1);
	dma_set_read_from_peripheral(DMA1, DMA_CHANNEL1);
	dma_set_peripheral_address(DMA1, DMA_CHANNEL1, (uint32_t) &ADC1_DR);
	/* The array adc_values[] is filled with the waveform data to be output */
	dma_set_memory_address(DMA1, DMA_CHANNEL1, (uint32_t) adc_values);
	dma_set_number_of_data(DMA1, DMA_CHANNEL1, ADC_NUM_CHANNELS);
	//dma_enable_transfer_complete_interrupt(DMA1, DMA_CHANNEL1);
	dma_enable_channel(DMA1, DMA_CHANNEL1);

	adc_enable_dma(ADC1);

	// GO!
	adc_power_on(ADC1);

}

#if 0
/* Set up timer to fire freq times per second */
static void init_systick(int freq)
{
	systick_set_clocksource(STK_CSR_CLKSOURCE_AHB);
	/* clear counter so it starts right away */
	STK_CVR = 0;

	systick_set_reload(rcc_ahb_frequency / freq);
	systick_counter_enable();
	systick_interrupt_enable();
}
#endif


int main(void)
{
	uint16_t cpuload = 0;
	uint64_t timebase_ms = 0;
	char msg[128];
	char number[FXP_STR_MAXLEN];
	uint8_t sentSomething = 0;

	// Calculated values
	//fxp_t VIN_SCALE = fxp_from_float(3.3f * (100 + 12.4f) / 12.4f / 4095.0f);
	//fxp_t VOUT_SCALE = fxp_from_float(3.3f * (100 + 12.0f) / 12.0f / 4095.0f);
	//fxp_t CURRENT_SCALE = fxp_from_float(9.7f / 4095.0f);

	// Calibrated from measurements
	fxp_t VIN_SCALE = fxp_from_float(12.11f / 1600.0f);
	fxp_t VOUT_SCALE = fxp_from_float(12.6f / 1620.0f);
	fxp_t CURRENT_SCALE = fxp_from_float(9.01f / 4095.0f);

	init_clock();
	init_gpio();
	init_adc();
	init_timer();

	lcd_init();
	debug_init();

	debug_send_string("Init complete\r\n");

	// boost converter PWM initial value
	//timer_set_oc_value(TIM3, TIM_OC1, 0);
	
	//init_systick(1000);

	// triggered every 1 ms
	while (1) {
		// let the ADC+DMA do its work
		adc_start_conversion_regular(ADC1);


		/*

		// *** Do some calculations while ADC converts ***

		// Ramp up target voltage
		if((targetVoltage < TARGET_VOLTAGE) && (voltRampUpCountdown-- == 0)) {
			targetVoltage += 2.0f;
			voltRampUpCountdown = VOLTAGE_UP_INTERVAL;

			if(targetVoltage > TARGET_VOLTAGE) {
				targetVoltage = TARGET_VOLTAGE;
			}
		}

		// read ADC value
		while(!adc_eoc(ADC1));
		adcval = adc_read_regular(ADC1);

		// scale current measurement
		curVoltage = VOLTAGE_MEAS_MAX * adcval / 4096.0f;

		// calculate error values
		pErr = targetVoltage - curVoltage;
		iErr += pErr;

		// limit integral error range
		if     (iErr >  IERR_LIMIT) iErr =  IERR_LIMIT;
		else if(iErr < -IERR_LIMIT) iErr = -IERR_LIMIT;

		// calculate the controller output ("action")
		controlAction = pErr * PGAIN + iErr * IGAIN;

		// calculate resulting PWM value
		if(controlAction > MAX_DUTY_CYCLE) {
			pwm_value = (int)(PWM_PERIOD * MAX_DUTY_CYCLE);
		} else if(controlAction > 0) {
			pwm_value = (int)(controlAction * PWM_PERIOD);
		} else {
			pwm_value = 0;
		}
		*/

		//timer_set_oc_value(TIM3, TIM_OC1, pwm_value);

		/*
		if((timebase_ms % 500) == 10) {
			sprintf(msg, "Audio PWM: %lu",
					dbg_audio_pwm_value);
			debug_send_string(msg);
			sentSomething = 1;
		}
		*/

		// wait for DMA transfer to complete
		while(!dma_get_interrupt_flag(DMA1, DMA_CHANNEL1, DMA_TCIF) && wait_frame);
		dma_clear_interrupt_flags(DMA1, DMA_CHANNEL1, DMA_TCIF);

		if((timebase_ms % 500) == 0) {
			debug_send_string("ADC:");

			for(uint8_t i = 0; i < ADC_NUM_CHANNELS; i++) {
				fxp_format_int(adc_values[i], msg);
				debug_send_string(" ");
				debug_send_string(msg);
			}

			fxp_t scaled_val;

			scaled_val = fxp_mult(fxp_from_int(adc_values[0]), VIN_SCALE);
			fxp_format(scaled_val, msg, 3);
			debug_send_string("\r\nInput[V]:   ");
			debug_send_string(msg);

			scaled_val = fxp_mult(fxp_from_int(adc_values[1]), VOUT_SCALE);
			fxp_format(scaled_val, msg, 3);
			debug_send_string("\r\nOutput[V]:  ");
			debug_send_string(msg);

			scaled_val = fxp_mult(fxp_from_int(adc_values[2]), CURRENT_SCALE);
			fxp_format(scaled_val, msg, 3);
			debug_send_string("\r\nCurrent[A]: ");
			debug_send_string(msg);

			sentSomething = 1;
		}

		if(sentSomething) {
			debug_send_string("\r\n");
			sentSomething = 0;
		}

		if(lcd_setup()) {
			lcd_process();

			if((timebase_ms % 500) == 0) {
				fxp_t scaled_val;

				lcd_set_cursor_pos(1, 0);

				scaled_val = fxp_mult(fxp_from_int(adc_values[0]), VIN_SCALE);
				fxp_format(scaled_val, number, 1);
				fxp_right_align(number, msg, 4, ' ');
				lcd_send_string("I:");
				lcd_send_string(msg);
				lcd_send_string("V ");

				scaled_val = fxp_mult(fxp_from_int(adc_values[1]), VOUT_SCALE);
				fxp_format(scaled_val, number, 1);
				fxp_right_align(number, msg, 4, ' ');
				lcd_send_string("O:");
				lcd_send_string(msg);
				lcd_send_string("V ");

				lcd_set_cursor_pos(0, 8);

				scaled_val = fxp_mult(fxp_from_int(adc_values[2]), CURRENT_SCALE);
				scaled_val = fxp_mult(scaled_val, fxp_from_int(1000)); // A -> mA
				fxp_format(scaled_val, number, 0);
				fxp_right_align(number, msg, 4, ' ');
				lcd_send_string(msg);
				lcd_send_string("mA");
			}

			if((timebase_ms % 1000) == 10) {
				cpuload /= 1000;

				lcd_set_cursor_pos(0, 0);

				fxp_format_int((int32_t)cpuload, number);
				fxp_right_align(number, msg, 3, '0');
				lcd_send_string("L:0.");
				lcd_send_string(msg);
			}
		}

		// cpu load = timer1 value after main loop operations
		cpuload += timer_get_counter(TIM3);

		timebase_ms++;

		while(wait_frame);
		wait_frame = 1;
	}

	return 0;
}

/* Called when systick fires */
void sys_tick_handler(void)
{
	wait_frame = 0;
}

void tim3_isr(void)
{
	// check for update interrupt
	if(timer_interrupt_source(TIM3, TIM_SR_UIF)) {
		wait_frame = 0;
		timer_clear_flag(TIM3, TIM_SR_UIF);
	}
}

void hard_fault_handler(void)
{
	while (1);
}