#include "main.h"

#include "stm32l100c_discovery.h"

#include "ssd1306.h"

#include "config.h"

// USB includes

#include "hw_config.h"

#include "usb_lib.h"

#include "usb_desc.h"

#include "usb_pwr.h"

#include "stringhelpers.h"

// TODO: Grab buttonpresses with interrupts

// TODO: Eliminate screen buffer since we aren't using it...

// USB Supporting Vars

extern __IO uint8_t Receive_Buffer[64];

extern __IO  uint32_t Receive_length ;

extern __IO  uint32_t length ;

uint8_t Send_Buffer[64];

uint32_t packet_sent=1;

uint32_t packet_receive=1;

// State definition

enum state {

    STATE_IDLE = 0,

    STATE_SETP,

    STATE_SETI,

    STATE_SETD,

    STATE_SETWINDUP,

    STATE_PREHEAT_BREW,

    STATE_MAINTAIN_BREW,

    STATE_PREHEAT_STEAM,

    STATE_MAINTAIN_STEAM,

};

static __IO uint32_t TimingDelay;

// Move to header file

void init_gpio();

void init_spi();

void process();

void machine();

void delay(__IO uint32_t nTime);

int main(void)

{

    // Init clocks

    SystemInit();

    // Init GPIO

    init_gpio();

    // Init USB

    //Set_USBClock();

    //USB_Interrupts_Config();

    //USB_Init();

    // Turn on power LED

    GPIO_SetBits(LED_POWER);

    // TODO: Awesome pwm of power LED (TIM4_CH4 or TIM11_CH1)

    // Configure 1ms SysTick (change if more temporal resolution needed) 

    RCC_ClocksTypeDef RCC_Clocks;

    RCC_GetClocksFreq(&RCC_Clocks);

    SysTick_Config(RCC_Clocks.HCLK_Frequency / 1000);

    // Init SPI busses

    init_spi();

    // Init OLED over SPI

    ssd1306_Init();

    ssd1306_clearscreen();

    // Startup screen 

    ssd1306_DrawString("therm v0.1", 1, 40);

    ssd1306_DrawString("protofusion.org/therm", 3, 0);

    delay(1500);

    ssd1306_clearscreen();

    GPIO_ResetBits(LED_STAT);

    // Main loop

    while(1)

    {

        // Process sensor inputs

        process();

        // Run state machine

        machine(); 

    }

}

// Read temperature and update global temp vars

int16_t temp = 0;

uint8_t temp_frac = 0;

void update_temp() {

    // Assert CS

    GPIO_ResetBits(MAX_CS);

    delay(1);

    // This may not clock at all... might need to send 16 bits first

        temp_pre = temp_pre >> 2; // Drop 2 lowest bits

        temp_frac = temp_pre & 0b11; // get fractional part

        temp_frac *= 25; // each bit is .25 a degree, up to fixed point

        temp_pre = temp_pre >> 2; // Drop 2 fractional bits 

        if(sign) {

            temp = -temp_pre;

        }

        else {

            temp = temp_pre;

        }

    }

    // Deassert CS

    delay(1);

    GPIO_SetBits(MAX_CS);

}

// PID implementation

int16_t last_pid_temp = 0;

uint8_t last_pid_temp_frac = 0;

int16_t i_state = 0;

int16_t update_pid(uint16_t k_p, uint16_t k_i, uint16_t k_d, int16_t temp, uint8_t temp_frac, int16_t setpoint) 

{

  // Calculate instantaneous error

  int16_t error = (int16_t)setpoint - (int16_t)temp; // TODO: Use fixed point fraction

  // Proportional component

  int16_t p_term = k_p * error;

  // Error accumulator (integrator)

  i_state += error;

  // to prevent the iTerm getting huge despite lots of 

  //  error, we use a "windup guard" 

  // (this happens when the machine is first turned on and

  // it cant help be cold despite its best efforts)

  // not necessary, but this makes windup guard values 

  // relative to the current iGain

  int16_t windup_guard_res = WINDUP_GUARD_GAIN / k_i;  

  // Calculate integral term with windup guard 

  if (i_state > windup_guard_res) 

    i_state = windup_guard_res;

  else if (i_state < -windup_guard_res) 

  // Save temperature for next iteration

  last_pid_temp = temp;

  last_pid_temp_frac = temp_frac;

  int16_t result = p_term + i_term - d_term;

  // Put out tenths of percent, 0-1000. 

  if(result > 1000)

    result = 1000;

  else if(result < -1000)

    result = -1000;

  // Return feedback

  return result;

}

uint32_t ticks = 0;

uint32_t last_ssr_on = 0;

uint32_t last_led = 0;

int32_t setpoint = 0;

int16_t ssr_output = 0; // Duty cycle of ssr, 0 to SSR_PERIOD 

uint8_t pid_enabled = 0;

// Process things

void process()

{

    update_temp(); // Read MAX31855

    // TODO: Add calibration offset (linear)

    if(ticks - last_led > 400) 

    {

        GPIO_ToggleBits(LED_POWER);

        last_led = ticks;

    }

    // Every 200ms, set the SSR on unless output is 0

    if((ticks - last_ssr_on > SSR_PERIOD))

    {

        if(pid_enabled) 

        {

            // Get ssr output for next time

            int16_t power_percent = update_pid(k_p, k_i, k_d, temp, temp_frac, setpoint);

            //power-percent is 0-1000

    //ssd1306_DrawString("        ", 3, 40);

    ssd1306_DrawString(tempstr, 3, 40);

    ssd1306_DrawString("-> ", 3, 80);

    itoa(setpoint, tempstr);

    ssd1306_DrawString("    ", 3, 95);

    ssd1306_DrawString(tempstr, 3, 95);

}

uint8_t state = STATE_IDLE;

uint8_t goto_mode = 2;

// State machine

uint8_t sw_btn_last = 0;

uint8_t sw_up_last = 0;

uint8_t sw_down_last = 0;

uint8_t sw_left_last = 0;

uint8_t sw_right_last = 0;

#define SW_BTN_PRESSED (sw_btn_last == 0 && sw_btn == 1) // rising edge on buttonpress

#define SW_UP_PRESSED (sw_up_last == 0 && sw_up == 1)

#define SW_DOWN_PRESSED (sw_down_last == 0 && sw_down == 1)

#define SW_LEFT_PRESSED (sw_left_last == 0 && sw_left == 1)

#define SW_RIGHT_PRESSED (sw_right_last == 0 && sw_right == 1)

void machine()

{

    uint8_t last_state = state;

    uint8_t sw_btn = !GPIO_ReadInputDataBit(SW_BTN);

    uint8_t sw_up = !GPIO_ReadInputDataBit(SW_UP);

    uint8_t sw_down = !GPIO_ReadInputDataBit(SW_DOWN);

    uint8_t sw_left = !GPIO_ReadInputDataBit(SW_LEFT);

    uint8_t sw_right = !GPIO_ReadInputDataBit(SW_RIGHT);

    switch(state)

    {

        // Idle state

        case STATE_IDLE:

        {

            // Write text to OLED

            // [ therm :: idle ]

            ssd1306_DrawString("therm :: idle ", 0, 40);

            pid_enabled = 0;

            char tempstr[6];

            itoa_fp(temp, temp_frac, tempstr);

            ssd1306_DrawString("Temp: ", 3, 40);

            ssd1306_DrawString("    ", 3, 72);

            // Event Handler

            // N/A

        } break;

        case STATE_SETWINDUP:

        {

            // Write text to OLED

            // [ therm :: set windup ]

            // [ g = 12         ]

            ssd1306_DrawString("Windup Guard", 0, 40);

            ssd1306_drawlogo();

            char tempstr[6];

            itoa(windup_guard, tempstr);

            ssd1306_DrawString("G=", 1, 45);

            ssd1306_DrawString("    ", 1, 57);

            ssd1306_DrawString(tempstr, 1, 57);

            ssd1306_DrawString("Press to accept", 3, 40);

            // Button handler

            if(SW_BTN_PRESSED) {

            }

            else if(!GPIO_ReadInputDataBit(SW_UP)) {

                windup_guard++;

            }

            else if(!GPIO_ReadInputDataBit(SW_DOWN) && windup_guard > 0) {

                windup_guard--;

            }

            // Event Handler

            // N/A

        } break;

        case STATE_PREHEAT_BREW:

        {

            // Write text to OLED

            // [ therm : preheating brew ]

            // [ 30 => 120 C             ]

            ssd1306_DrawString("Preheating...", 0, 40);

            ssd1306_drawlogo();

            draw_setpoint();

            pid_enabled = 1;

            // Button handler

            if(SW_BTN_PRESSED) {

                state = STATE_IDLE;

            }

            else if(!GPIO_ReadInputDataBit(SW_UP)) {

               setpoint++; 

            }

            else if(!GPIO_ReadInputDataBit(SW_DOWN) && setpoint > 0) {

                setpoint--;

            }

               setpoint++; 

            }

            else if(!GPIO_ReadInputDataBit(SW_DOWN) && setpoint > 0) {

                setpoint--;

            }

            // Event Handler

            // N/A

        } break;

        // Something is terribly wrong

        default:

        {

            state = STATE_IDLE;

            pid_enabled = 0;

        } break;

    }

    if(last_state != state) {

        // Clear screen on state change

        ssd1306_clearscreen();

    }

    sw_btn_last = sw_btn;

    sw_up_last = sw_up;

    sw_down_last = sw_down;

    sw_left_last = sw_left;

    sw_right_last = sw_right;

}

// Delay a number of systicks

void delay(__IO uint32_t nTime)

{

  TimingDelay = nTime;

  while(TimingDelay != 0);

}

// ISR-triggered decrement of delay and increment of tickcounter

void TimingDelay_Decrement(void)

{

  if (TimingDelay != 0x00)

  { 

    TimingDelay--;

  }

  ticks++;

}