#include "stm32f0xx_hal.h"

#include "config.h"
#include "ssd1306.h"
#include "eeprom_min.h"
#include "gpio.h"
#include "spi.h"
#include "stringhelpers.h"

#include "usb_device.h"
#include "usbd_cdc_if.h"


// Prototypes
// Move to header file
void process();
void machine();
void restore_settings();
void save_settings();
void save_setpoints();
void SystemClock_Config(void);

///////////////////////
enum tempunits {
    TEMP_UNITS_CELSIUS = 0,
    TEMP_UNITS_FAHRENHEIT,
};

// State definition
enum state {
    STATE_IDLE = 0,

    STATE_SETP,
    STATE_SETI,
    STATE_SETD,
    STATE_SETSTEPS,
    STATE_SETWINDUP,
    STATE_SETBOOTTOBREW,
    STATE_SETUNITS,

    STATE_PREHEAT_BREW,
    STATE_MAINTAIN_BREW,
    STATE_PREHEAT_STEAM,
    STATE_MAINTAIN_STEAM,

    STATE_TC_ERROR
};

uint8_t state = STATE_IDLE;


// Globalish setting vars
uint8_t boottobrew = 0;
uint8_t temp_units = TEMP_UNITS_CELSIUS;
uint16_t windup_guard = 1;
uint16_t k_p = 1;
uint16_t k_i = 1;
uint16_t k_d = 1;
uint8_t ignore_tc_error  = 0;
int16_t setpoint_brew = 0;
int16_t setpoint_steam = 0;

SPI_HandleTypeDef hspi1;

static __IO uint32_t TimingDelay;


void deinit(void)
{
    HAL_DeInit();
}

volatile int i=0;
int main(void)
{

    /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
    HAL_Init();

    /* Configure the system clock */
    SystemClock_Config();

    /* Initialize all configured peripherals */
    init_gpio();
    MX_USB_DEVICE_Init();

    // USB startup delay
    HAL_Delay(1000);
    HAL_GPIO_WritePin(LED_POWER, 1);

    // TODO: Awesome pwm of power LED 

    // 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);

    HAL_Delay(1500);
    ssd1306_clearscreen();
    
    restore_settings();
    if(boottobrew)
      state = STATE_PREHEAT_BREW; // Go to brew instead of idle if configured thusly

    // Main loop
    while(1)
    {
        // Process sensor inputs
        process();

        // Run state machine
        machine(); 
    }

}

/** System Clock Configuration
*/
void SystemClock_Config(void)
{

  RCC_OscInitTypeDef RCC_OscInitStruct;
  RCC_ClkInitTypeDef RCC_ClkInitStruct;
  RCC_PeriphCLKInitTypeDef PeriphClkInit;

  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI48;
  RCC_OscInitStruct.HSI48State = RCC_HSI48_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
  HAL_RCC_OscConfig(&RCC_OscInitStruct);

  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_SYSCLK;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI48;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
  HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1);

  PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USB;
  PeriphClkInit.UsbClockSelection = RCC_USBCLKSOURCE_HSI48;
  HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit);

  __SYSCFG_CLK_ENABLE();

}


// Read temperature and update global temp vars
int32_t temp = 0;
uint8_t temp_frac = 0;
uint8_t state_resume = 0;


void update_temp() {

    // Assert CS
    HAL_GPIO_WritePin(MAX_CS, 0);

    uint8_t rxdatah[1] = {0x00};
    uint8_t rxdatal[1] = {0x00};

    HAL_SPI_Receive(&hspi1, rxdatah, 1, 100);
    HAL_SPI_Receive(&hspi1, rxdatal, 1, 100);

    // Release CS
    HAL_GPIO_WritePin(MAX_CS, 1);

    // Assemble data array into one var
    uint16_t temp_pre = rxdatal[0] | (rxdatah[0]<<8);

    if(temp_pre & 0b0000000000000010) {
        ssd1306_clearscreen();
        ssd1306_DrawString("Fatal Error", 3, 35);
        HAL_Delay(100);
        state = STATE_TC_ERROR;
    }
    else if(temp_pre & 0b0000000000000001 && !ignore_tc_error) {
        state_resume = state;
        state = STATE_TC_ERROR;
        temp = 0;
        temp_frac = 0;
    }
    else 
    {
        if(state == STATE_TC_ERROR)
        {
            state = state_resume;
            ssd1306_clearscreen();
        }

        uint8_t sign = temp >> 15;// top bit is sign

        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 

        int8_t signint;

        if(sign) {
            signint = -1;
        }
        else {
            signint = 1;
        }

        // Convert to Fahrenheit
        if(temp_units == TEMP_UNITS_FAHRENHEIT)
        {
            temp = signint * ((temp_pre*100) + temp_frac);
            temp = temp * 1.8;
            temp += 3200;
            temp_frac = temp % 100;
            temp /= 100;
        }

        // Use Celsius values
        else
        {
            temp = temp_pre * signint;
        }
    }

    // Print temp to cdc
    CDC_Transmit_FS("Temp: ", 6);
    char tempstr[6];
    zitoa(temp, tempstr);
    CDC_Transmit_FS(tempstr, sizeof(tempstr));

    CDC_Transmit_FS("\r\n", 2);
    CDC_Transmit_FS("\r\n", 2);
    CDC_Transmit_FS("\r\n", 2);
    CDC_Transmit_FS("\r\n", 2);
    CDC_Transmit_FS("\r\n", 2);

}


// PID implementation
// TODO: Make struct that has the last_temp and i_state in it, pass by ref. Make struct that has other input values maybe.
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 / 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 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)
    uint32_t ticks = HAL_GetTick();

    if(ticks - last_led > 400) 
    {
        HAL_GPIO_TogglePin(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, 10);
            ssd1306_DrawString(tempstr, 0, 90);

            HAL_GPIO_WritePin(SSR_PIN, 1);
            last_ssr_on = ticks;
        }
    }
    
    // Kill SSR after elapsed period less than SSR_PERIOD 
    if(ticks - last_ssr_on > ssr_output || ssr_output == 0)
    {
        HAL_GPIO_WritePin(SSR_PIN, 0);
    }
}

void draw_setpoint() {
    char tempstr[3];
    itoa_fp(temp, temp_frac, tempstr);
    ssd1306_DrawStringBig("      ", 3, 0);
    ssd1306_DrawStringBig(tempstr, 3, 0);
    ssd1306_DrawStringBig(">", 3, 74);
    itoa(setpoint, tempstr, 10);
    ssd1306_DrawStringBig("    ", 3, 90);
    ssd1306_DrawStringBig(tempstr, 3, 90);
}

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 save_settings()
{
/*
   Minimal_EEPROM_Unlock();
    // Try programming a word at an address divisible by 4
    Minimal_EEPROM_ProgramWord(EEPROM_BASE_ADDR + EEPROM_ADDR_BOOTTOBREW, boottobrew);
    Minimal_EEPROM_ProgramWord(EEPROM_BASE_ADDR + EEPROM_ADDR_WINDUP_GUARD, windup_guard);
    Minimal_EEPROM_ProgramWord(EEPROM_BASE_ADDR + EEPROM_ADDR_K_P, k_p);
    Minimal_EEPROM_ProgramWord(EEPROM_BASE_ADDR + EEPROM_ADDR_K_I, k_i);
    Minimal_EEPROM_ProgramWord(EEPROM_BASE_ADDR + EEPROM_ADDR_K_D, k_d);
    Minimal_EEPROM_ProgramWord(EEPROM_BASE_ADDR + EEPROM_ADDR_UNITS, temp_units);
    Minimal_EEPROM_Lock();
*/
}

void save_setpoints()
{
/*

    Minimal_EEPROM_Unlock();
    Minimal_EEPROM_ProgramWord(EEPROM_BASE_ADDR + EEPROM_ADDR_BREWTEMP, setpoint_brew);
    Minimal_EEPROM_ProgramWord(EEPROM_BASE_ADDR + EEPROM_ADDR_STEAMTEMP, setpoint_steam); 
    Minimal_EEPROM_Lock();
*/
}


// TODO: Make a struct that has all settings in it. Pass by ref to this func in a library.
void restore_settings()
{
/*    Minimal_EEPROM_Unlock();
    while(Minimal_FLASH_GetStatus()==FLASH_BUSY);
    boottobrew = (*(__IO uint32_t*)(EEPROM_BASE_ADDR + EEPROM_ADDR_BOOTTOBREW));
    
    while(Minimal_FLASH_GetStatus()==FLASH_BUSY);
    windup_guard = (*(__IO uint32_t*)(EEPROM_BASE_ADDR + EEPROM_ADDR_WINDUP_GUARD));
    
    while(Minimal_FLASH_GetStatus()==FLASH_BUSY);
    k_p = (*(__IO uint32_t*)(EEPROM_BASE_ADDR + EEPROM_ADDR_K_P));

    while(Minimal_FLASH_GetStatus()==FLASH_BUSY);
    k_i = (*(__IO uint32_t*)(EEPROM_BASE_ADDR + EEPROM_ADDR_K_I));

    while(Minimal_FLASH_GetStatus()==FLASH_BUSY);
    k_d = (*(__IO uint32_t*)(EEPROM_BASE_ADDR + EEPROM_ADDR_K_D));
    
    while(Minimal_FLASH_GetStatus()==FLASH_BUSY);
    setpoint_brew = (*(__IO uint32_t*)(EEPROM_BASE_ADDR + EEPROM_ADDR_BREWTEMP));

    while(Minimal_FLASH_GetStatus()==FLASH_BUSY);
    setpoint_steam = (*(__IO uint32_t*)(EEPROM_BASE_ADDR + EEPROM_ADDR_STEAMTEMP));    
    while(Minimal_FLASH_GetStatus()==FLASH_BUSY);
    temp_units = (*(__IO uint32_t*)(EEPROM_BASE_ADDR + EEPROM_ADDR_UNITS));    

    Minimal_EEPROM_Lock(); */
}

int16_t last_temp = 21245;


///////////////////////////////////////////////////////////////////////////////////////
/// freaking multiple setpoint support ///
uint8_t step_duration[10] = {0,0,0,0,0,0,0,0,0,0};
int16_t step_setpoint[10] = {0,0,0,0,0,0,0,0,0,0};
uint8_t final_setpoint = 0;

// Multiple screens to set setpoint and duration on each screen
// press center to go to the next one, and press left or right or something to confirm

// When executing, complete on time AND(?) temperature. Maybe allow switching to OR via settings

////////////////////////////////////////////////////////////////////////////////////////////////

void machine()
{
    uint8_t last_state = state;
    
    uint8_t temp_changed = temp != last_temp;
    last_temp = temp;

    uint8_t sw_btn = !HAL_GPIO_ReadPin(SW_BTN);
    uint8_t sw_up = !HAL_GPIO_ReadPin(SW_UP);
    uint8_t sw_down = !HAL_GPIO_ReadPin(SW_DOWN);
    uint8_t sw_left = !HAL_GPIO_ReadPin(SW_LEFT);
    uint8_t sw_right = !HAL_GPIO_ReadPin(SW_RIGHT);

    switch(state)
    {
        // Idle state
        case STATE_IDLE:
        {
            // Write text to OLED
            // [ therm :: idle ]
            ssd1306_DrawString("therm :: idle ", 0, 40);
            pid_enabled = 0;

            if(temp_changed) {
                char tempstr[6];
                itoa_fp(temp, temp_frac, tempstr);
                ssd1306_DrawString("Temp: ", 3, 40);
                ssd1306_DrawString("    ", 3, 72);
                ssd1306_DrawString(tempstr, 3, 72);
            }

            ssd1306_drawlogo();

            switch(goto_mode) {
                case 2:
                {
                    ssd1306_DrawString("-> heat     ", 1, 40);
                } break;

                case 1:
                {
                    ssd1306_DrawString("-> setup    ", 1, 40);
                } break;

                case 0:
                {
                    ssd1306_DrawString("-> reset    ", 1, 40);
                } break;
            }

            // Button handler
            if(SW_BTN_PRESSED) {
                switch(goto_mode) {
                    case 2:
                        state = STATE_PREHEAT_BREW;
                        break;
                    case 1:
                        state = STATE_SETP;
                        break;
                    case 0:
                    {
                        ssd1306_clearscreen();
                        ssd1306_DrawString("Entering Bootloader", 1, 0);
                        ssd1306_DrawString("(hopefully)", 2, 0);
                        HAL_Delay(1000);
                        *((unsigned long *)0x200017F0) = 0xDEADBEEF; // 6KB STM32F042
                        NVIC_SystemReset();

                        state = STATE_IDLE;
                    } break;

                    default:
                        state = STATE_PREHEAT_BREW;
                }
            }
            else if(SW_UP_PRESSED && goto_mode < 2) {
                goto_mode++;
            }
            else if(SW_DOWN_PRESSED && goto_mode > 0) {
                goto_mode--;
            }


            // Event Handler
            // N/A

        } break;

        case STATE_SETP:
        {
            // Write text to OLED
            // [ therm :: set p ]
            // [ p = 12         ]
            ssd1306_DrawString("Proportional", 0, 40);
            ssd1306_drawlogo();

            char tempstr[6];
            itoa(k_p, tempstr, 10);
            ssd1306_DrawString("P=", 1, 45);
            ssd1306_DrawString("    ", 1, 57);
            ssd1306_DrawString(tempstr, 1, 57);

            ssd1306_DrawString("Press to accept", 3, 40);
            
            // Button handler
            if(SW_BTN_PRESSED) {
                state = STATE_SETI;
            }
            else {
                user_input(&k_p);
            }

            // Event Handler
            // N/A
 
        } break;

        case STATE_SETI:
        {
            // Write text to OLED
            // [ therm :: set i ]
            // [ i = 12         ]
            ssd1306_DrawString("Integral", 0, 40);
            ssd1306_drawlogo();

            char tempstr[6];
            itoa(k_i, tempstr, 10);
            ssd1306_DrawString("I=", 1, 45);
            ssd1306_DrawString("    ", 1, 57);
            ssd1306_DrawString(tempstr, 1, 57);

            ssd1306_DrawString("Press to accept", 3, 40);
            
            // Button handler
            if(SW_BTN_PRESSED) {
                state = STATE_SETD;
            }
            else {
                user_input(&k_i);
            }

            // Event Handler
            // N/A
 
        } break;

        case STATE_SETD:
        {
            // Write text to OLED
            // [ therm :: set d ]
            // [ d = 12         ]
            ssd1306_DrawString("Derivative", 0, 40);
            ssd1306_drawlogo();

            char tempstr[6];
            itoa(k_d, tempstr, 10);
            ssd1306_DrawString("D=", 1, 45);
            ssd1306_DrawString("    ", 1, 57);
            ssd1306_DrawString(tempstr, 1, 57);

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

            // Button handler
            if(SW_BTN_PRESSED) {
                state = STATE_SETWINDUP;
            }
            else {
                user_input(&k_d);
            }

            // Event Handler
            // N/A
 
        } break;

        case STATE_SETSTEPS:
        {
            // Write text to OLED
            // [ step #1:: Duration: ### ]
            // [           Setpoint: ### ]
            char tempstr[6];

            itoa(final_setpoint, tempstr, 10);
            ssd1306_DrawString("Step #", 0, 0);
            ssd1306_DrawString(tempstr, 0, 40);

            ssd1306_DrawString("Duration: ", 0, 5);
            itoa(step_duration[final_setpoint], tempstr, 10);
            ssd1306_DrawString(tempstr, 0, 70);

            ssd1306_DrawString("Setpoint: ", 0, 0);
            itoa(step_setpoint[final_setpoint], tempstr, 10);
            ssd1306_DrawString(tempstr, 0, 70);

            ssd1306_DrawString("Press to accept", 3, 40);
            
            // Button handler - TODO: increment max_step if pressed
            // return and go to next state otherwise
            if(SW_BTN_PRESSED) {
                state = STATE_SETSTEPS;
                final_setpoint++;
            }
        //    else if(SW_LEFT_PRESSED) {
        //        state++; // go to next state or something
        //    }
            else {
                user_input(&k_p);
            }

            // 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, 10);
            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) {
                state = STATE_SETBOOTTOBREW;
            }
            else {
                user_input(&windup_guard);
            }

            // Event Handler
            // N/A
 
        } break;

        case STATE_SETBOOTTOBREW:
        {
            // Write text to OLED
            // [ therm :: set windup ]
            // [ g = 12         ]
            ssd1306_DrawString("Start on Boot", 0, 40);
            ssd1306_drawlogo();

            ssd1306_DrawString("sob=", 1, 45);
            
            if(boottobrew)
                ssd1306_DrawString("Enabled ", 1, 70);
            else
                ssd1306_DrawString("Disabled", 1, 70);

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

            // Button handler
            if(SW_BTN_PRESSED) {
                state = STATE_SETUNITS;
            }
            else if(!HAL_GPIO_ReadPin(SW_UP)) {
                boottobrew = 1;
            }
            else if(!HAL_GPIO_ReadPin(SW_DOWN)) {
                boottobrew = 0;
            }

            // Event Handler
            // N/A
 
        } break;

        case STATE_SETUNITS:
        {
            // Write text to OLED
            // [ therm :: set windup ]
            // [ g = 12         ]
            ssd1306_DrawString("Units: ", 0, 40);
            ssd1306_drawlogo();

            if(temp_units == TEMP_UNITS_FAHRENHEIT)
                ssd1306_DrawString("Fahrenheit", 1, 60);
            else
                ssd1306_DrawString("Celsius   ", 1, 60);

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

            // Button handler
            if(SW_BTN_PRESSED) {
                save_settings();
                state = STATE_IDLE;
            }
            else if(!HAL_GPIO_ReadPin(SW_UP)) {
                temp_units = TEMP_UNITS_FAHRENHEIT;
            }
            else if(!HAL_GPIO_ReadPin(SW_DOWN)) {
                temp_units = TEMP_UNITS_CELSIUS;
            }

            // Event Handler
            // N/A
 
        } break;


        case STATE_PREHEAT_BREW:
        {
            // Write text to OLED
            // [ therm : preheating brew ]
            // [ 30 => 120 C             ]
            ssd1306_DrawString("Preheating...", 0, 0);
            //ssd1306_drawlogo();
            draw_setpoint();
            pid_enabled = 1;
	    setpoint = setpoint_brew;

            // Button handler
            if(SW_BTN_PRESSED) {
		save_setpoints(); // TODO: Check for mod
                state = STATE_IDLE;
            }
            else {
                user_input(&setpoint_brew);
            }

            // Event Handler
            if(temp >= setpoint) {
                state = STATE_MAINTAIN_BREW;
            }
 
        } break;

        case STATE_MAINTAIN_BREW:
        {
            // Write text to OLED
            // [ therm : ready to brew ]
            // [ 30 => 120 C           ]
            ssd1306_DrawString("Preheated!", 0, 0);
            //ssd1306_drawlogo();
            draw_setpoint();
            pid_enabled = 1;
	    setpoint = setpoint_brew;

            // Button handler
            if(SW_BTN_PRESSED) {
		save_setpoints(); // TODO: Check for mod
                state = STATE_IDLE;
            }
            else {
                user_input(&setpoint_brew);
            }

            // Event Handler
            // N/A
 
        } break;

        case STATE_PREHEAT_STEAM:
        {
            // Write text to OLED
            // [ therm : preheating steam ]
            // [ 30 => 120 C           ]
            ssd1306_DrawString("Preheating...", 0, 0);
            //ssd1306_drawlogo();
            draw_setpoint();
            pid_enabled = 1;
	    setpoint = setpoint_steam;
	    
            // Button handler
            if(SW_BTN_PRESSED) {
                state = STATE_IDLE;
		save_setpoints(); // TODO: Check for mod
            }
            else {
                user_input(&setpoint_steam);
            }

            // Event Handler
            if(temp >= setpoint) {
                state = STATE_MAINTAIN_STEAM;
            }
 
        } break;

        case STATE_MAINTAIN_STEAM:
        {
            // Write text to OLED
            // [ therm : ready to steam ]
            // [ 30 => 120 C            ]
            ssd1306_DrawString("Ready to Steam!", 0, 0);
            //ssd1306_drawlogo();
            draw_setpoint();
            pid_enabled = 1;
	    setpoint = setpoint_steam;

            // Button handler
            if(SW_BTN_PRESSED) {
                state = STATE_IDLE;
		save_setpoints(); // TODO: Check for mod
            }
            else {
                user_input(&setpoint_steam);
            }

            // Event Handler
            // N/A
 
        } break;

        case STATE_TC_ERROR:
        {
            // Write text to OLED
            // [ therm : ready to steam ]
            // [ 30 => 120 C            ]
            ssd1306_DrawString("Error:", 0, 0);
            ssd1306_DrawString("Connect thermocouple", 1, 0);
            ssd1306_DrawString("Press -> to ignore", 3, 0);

            // Button handler
            if(SW_BTN_PRESSED) {
                state = STATE_IDLE;
            }
            else if(SW_RIGHT_PRESSED) {
                ignore_tc_error = 1;
                state = STATE_IDLE;
            }
            // Event Handler
            // Maybe handle if TC is plugged in
            // N/A
 
        } break;

        // Something is terribly wrong
        default:
        {
            state = STATE_IDLE;
            pid_enabled = 0;

        } break;
            
    }

    if(last_state != state) {
        // Clear screen on state change
        goto_mode = 2;
        ssd1306_clearscreen();
    }

    // Last buttonpress
    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;
}



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