#ifndef CONFIG_H

#define CONFIG_H

#define SSR_PERIOD 200

#define LED_POWER GPIOB,GPIO_Pin_9

#define LED_STAT  GPIOA,GPIO_Pin_15

#define MAX_CS GPIOB,GPIO_Pin_12

#define SW_BTN  GPIOB, GPIO_Pin_3

#define SW_UP   GPIOB, GPIO_Pin_4

#define SW_DOWN GPIOB, GPIO_Pin_6

#define SW_LEFT GPIOB, GPIO_Pin_5

#define SW_RIGHT GPIOB, GPIO_Pin_7

#endif

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) 

    i_state = -windup_guard_res;

  int16_t i_term = k_i * i_state;

  // Calculate differential term (slope since last iteration)

  int16_t d_term = (k_d * (temp - last_pid_temp));

  // 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

            ssr_output = power_percent; //(((uint32_t)SSR_PERIOD * (uint32_t)10 * (uint32_t)100) * power_percent) / (uint32_t)1000000;

        }

        else 

        {

            ssr_output = 0;

        }

        // Only support heating (ssr_output > 0) right now

        if(ssr_output > 0) {

            char tempstr[6];

            itoa(ssr_output, tempstr);

            ssd1306_DrawString("#=", 2, 45);

            ssd1306_DrawString("    ", 2, 57);

            ssd1306_DrawString(tempstr, 2, 57);

            GPIO_SetBits(LED_STAT);

            last_ssr_on = ticks;

        }

    }

    // Kill SSR after elapsed period less than SSR_PERIOD 

    if(ticks - last_ssr_on > ssr_output)

    {

        GPIO_ResetBits(LED_STAT);

    }

}

void draw_setpoint() {

    char tempstr[3];

    itoa_fp(temp, temp_frac, tempstr);

    //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 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)

/*

 * uint8_t boottobrew = 0;

#define WINDUP_GUARD_GAIN 100

uint16_t windup_guard = WINDUP_GUARD_GAIN;

uint16_t k_p = 1;

uint16_t k_i = 1;

uint16_t k_d = 1;*/

#define EEPROM_ADDR_WINDUP_GUARD 	0x0808001C

#define EEPROM_ADDR_BOOTTOBREW		0x08080020

#define EEPROM_ADDR_K_P			0x8080024

#define EEPROM_ADDR_K_I			0x8080028

#define EEPROM_ADDR_K_D			0x808002C

#define EEPROM_ADDR_BREWTEMP		0x8080030

#define EEPROM_ADDR_STEAMTEMP		0x8080034

void save_settings()

{

    DATA_EEPROM_Unlock();

    // Try programming a word at an address divisible by 4

    DATA_EEPROM_ProgramWord(EEPROM_ADDR_BOOTTOBREW, boottobrew);

    DATA_EEPROM_ProgramWord(EEPROM_ADDR_WINDUP_GUARD, windup_guard);

    DATA_EEPROM_ProgramWord(EEPROM_ADDR_K_P, k_p);

    DATA_EEPROM_ProgramWord(EEPROM_ADDR_K_I, k_i);

    DATA_EEPROM_ProgramWord(EEPROM_ADDR_K_D, k_d);

    DATA_EEPROM_Lock();

}

void save_setpoints()

{

    DATA_EEPROM_Unlock();

    DATA_EEPROM_ProgramWord(EEPROM_ADDR_BREWTEMP, setpoint_brew);

    DATA_EEPROM_ProgramWord(EEPROM_ADDR_STEAMTEMP, setpoint_steam); 

    DATA_EEPROM_Lock();

}

// TODO: Save/restore temperature setpoint settings

void restore_settings()

{

    DATA_EEPROM_Unlock();

    while(FLASH_GetStatus()==FLASH_BUSY);

    boottobrew = (*(__IO uint32_t*)EEPROM_ADDR_BOOTTOBREW);

    while(FLASH_GetStatus()==FLASH_BUSY);

    windup_guard = (*(__IO uint32_t*)EEPROM_ADDR_WINDUP_GUARD);

    while(FLASH_GetStatus()==FLASH_BUSY);

    k_p = (*(__IO uint32_t*)EEPROM_ADDR_K_P);

    while(FLASH_GetStatus()==FLASH_BUSY);

    k_i = (*(__IO uint32_t*)EEPROM_ADDR_K_I);

    while(FLASH_GetStatus()==FLASH_BUSY);

    k_d = (*(__IO uint32_t*)EEPROM_ADDR_K_D);

    while(FLASH_GetStatus()==FLASH_BUSY);

    setpoint_brew = (*(__IO uint32_t*)EEPROM_ADDR_BREWTEMP);

    while(FLASH_GetStatus()==FLASH_BUSY);

    setpoint_steam = (*(__IO uint32_t*)EEPROM_ADDR_STEAMTEMP);    

    DATA_EEPROM_Lock();

}

void machine()