/*
 * ECE 3849 Lab2 starter project
 *
 * Gene Bogdanov    9/13/2017
 */
/* XDCtools Header files */
#include <xdc/std.h>
#include <xdc/runtime/System.h>
#include <xdc/cfg/global.h>

/* BIOS Header files */
#include <ti/sysbios/BIOS.h>
#include <ti/sysbios/knl/Task.h>

#include <stdint.h>
#include <stdbool.h>
#include "driverlib/interrupt.h"

uint32_t gSystemClock = 120000000; // [Hz] system clock frequency


#define PWM_FREQUENCY 20000 // PWM frequency = 20 kHz

uint32_t gSystemClock; // [Hz] system clock frequency
volatile uint32_t gTime = 0; // time in hundredths of a second
volatile uint8_t refresh = 1;

// assumming square lcd
#define HEIGHT LCD_VERTICAL_MAX
#define WIDTH LCD_HORIZONTAL_MAX
#define PIXELS_PER_DIV 20

#define VIN_RANGE 3.3 // volts
#define ADC_BITS 12
#define ADC_OFFSET 30

#define VOLTAGE_SCALES 5
const char * const gVoltageScaleStr[VOLTAGE_SCALES] = {
"100 mV", "200 mV", "500 mV", " 1 V", " 2 V"
};

const float gVoltageScale[VOLTAGE_SCALES] = {
    0.1, 0.2, 0.5, 1., 2.
};

#define TIME_SCALES 6
const char * const gTimeScaleStr[TIME_SCALES] = {
"100 ms", "50 ms", "20 ms", " 10 ms", "50 us", "20 us"
};

const uint64_t gTImeScale[TIME_SCALES] = {
    100 * 1000 / PIXELS_PER_DIV,
    50 * 1000 / PIXELS_PER_DIV,
    20 * 1000 / PIXELS_PER_DIV,
    10 * 1000 / PIXELS_PER_DIV,
    50 / PIXELS_PER_DIV,
    20 / PIXELS_PER_DIV,
};

int Trigger(bool rising) // search for edge trigger
{
    int x = gADCBufferIndex - (WIDTH / 2); // half screen width
    int x_stop = x - ADC_BUFFER_SIZE/2;
    for (; x > x_stop; x--) {
        if (rising) {
            if ( gADCBuffer[ADC_BUFFER_WRAP(x)] >= ADC_OFFSET &&
                gADCBuffer[ADC_BUFFER_WRAP(x-1)] < ADC_OFFSET) {
                break;
            }
        } else { // falling edge trigger
            if ( gADCBuffer[ADC_BUFFER_WRAP(x)] <= ADC_OFFSET &&
                gADCBuffer[ADC_BUFFER_WRAP(x-1)] > ADC_OFFSET) {
                break;
            }
        }
    }
    if (x == x_stop) // for loop ran to the end
    x = gADCBufferIndex - (WIDTH / 2); // reset x back to how it was initialized
    return x;
}



/*
 *  ======== main ========
 */
int main(void)
{
    IntMasterDisable();

    // hardware initialization goes here

    /* Start BIOS */
    BIOS_start();

    return (0);
}

void task0_func(UArg arg1, UArg arg2)
{
    IntMasterEnable();

    while (true) {
        // do nothing
    }
}

void draw(tContext &sContext) {
        // handle buttons
        Button button = (Button) 0;
        while (fifo_get(&button)) {
            switch (button) {
                case S1: // toggle edge
                    trigger_mode++;
                    trigger_mode %= 3;
                    break;
                case S2: // draw
                    refresh = !refresh;
                    break;
                case Up: // next scale
                    voltage_scale = (voltage_scale + 1) % VOLTAGE_SCALES;
                    break;
                case Down: // previous scale
                    voltage_scale = (voltage_scale + VOLTAGE_SCALES - 1) % VOLTAGE_SCALES;
                    break;
                case Right: // next scale
                    time_scale = (time_scale + 1) % TIME_SCALES;
                    set_frequency(gTImeScale[time_scale]);
                    break;
                case Left: // previous scale
                    time_scale = (time_scale + TIME_SCALES - 1) % TIME_SCALES;
                    set_frequency(gTImeScale[time_scale]);
                    break;
            }
        }

        GrContextForegroundSet(&sContext, ClrBlack);
        GrRectFill(&sContext, &rectFullScreen); // fill screen with black

        GrContextForegroundSet(&sContext, ClrBlue);

        // draw gridlines from the center out
        uint8_t xy_pos;
        for (xy_pos = HEIGHT/2; xy_pos < HEIGHT; xy_pos += PIXELS_PER_DIV) {
            GrLineDrawV(&sContext, xy_pos, 0, 128); // right
            GrLineDrawV(&sContext, HEIGHT - xy_pos, 0, 128); // left

            GrLineDrawH(&sContext, 0, 128, xy_pos); // down
            GrLineDrawH(&sContext, 0, 128, HEIGHT - xy_pos); // up
        }


        // info
        GrContextForegroundSet(&sContext, ClrWheat);
        GrStringDraw(&sContext, gVoltageScaleStr[voltage_scale], /*length*/ -1, /*x*/ 0, /*y*/ 0, /*opaque*/ false);
        GrStringDraw(&sContext, gTimeScaleStr[time_scale], /*length*/ -1, /*x*/ 60, /*y*/ 0, /*opaque*/ false);
        snprintf(str, sizeof(str), "CPU Load %.1f%%", usage_percent); 
        GrStringDraw(&sContext, str, /*length*/ -1, /*x*/ 0, /*y*/ HEIGHT - 10, /*opaque*/ false);

        switch (trigger_mode) {
            case 1:
                GrStringDraw(&sContext, "^", /*length*/ -1, /*x*/ WIDTH - 10, /*y*/ 0, /*opaque*/ false);
                break;
            case 0:
                GrStringDraw(&sContext, "v", /*length*/ -1, /*x*/ WIDTH - 10, /*y*/ 0, /*opaque*/ false);
                break;
            case 2:
                GrStringDraw(&sContext, "-", /*length*/ -1, /*x*/ WIDTH - 10, /*y*/ 0, /*opaque*/ false);
                break;
        }

        // display graph
        #define LOCAL_BUF_LEN 128
        uint16_t local_adc_buffer[LOCAL_BUF_LEN]; // copy of adc buffer
        int32_t adc_current_index;
        int32_t j;
        if (refresh) {
            int trigger;
            if (trigger_mode == 2) {
                trigger = gADCBufferIndex - (WIDTH / 2); // show latest if trigger disabled
            } else {
                trigger = Trigger(trigger_mode);
            }

            adc_current_index = trigger - (WIDTH / 2);
            for (j=0; j<LOCAL_BUF_LEN; j++) {
                local_adc_buffer[j] = gADCBuffer[ADC_BUFFER_WRAP(adc_current_index + j)];
            }
        }

        float fVoltsPerDiv = gVoltageScale[voltage_scale];
        float fScale = (VIN_RANGE * PIXELS_PER_DIV)/((1 << ADC_BITS) * fVoltsPerDiv);

        GrContextForegroundSet(&sContext, ClrYellow);
        for(j=0; j<LOCAL_BUF_LEN; j++) {
            #define MIN(a,b) (((a)<(b))?(a):(b))
            #define MAX(a,b) (((a)>(b))?(a):(b))
            #define CONSTRAIN(x) MAX(MIN(HEIGHT - 1, x), 0)
            #define TRANSPOSE(x) CONSTRAIN((HEIGHT/2) - (int)roundf(fScale * ((int)x - ADC_OFFSET)))
            uint32_t upper,lower, current, last;

            if (j==0) {
                upper = TRANSPOSE(local_adc_buffer[j]);
                lower = upper;
                last = upper;
            } else {
                current = TRANSPOSE(local_adc_buffer[j]);
                
                upper = MAX(current, last);
                lower = MIN(current, last);

                last = current;
            }

            GrLineDrawV(&sContext, j, lower, upper);
        }
}