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);

void restore_settings();

void save_settings();

void save_setpoints();

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();

    restore_settings();

    if(boottobrew)

      state = STATE_PREHEAT_BREW; // Go to brew instead of idle if configured thusly

    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

    SPI_I2S_SendData(SPI2, 0xAAAA); // send dummy data

    //SPI_I2S_SendData(SPI2, 0xAA); // send dummy data

    uint16_t temp_pre = SPI_I2S_ReceiveData(SPI2);

    if(temp_pre & 0b0000000000000010) {

        ssd1306_DrawString("Fatal Error", 2, 35);

    }

    else if(temp_pre & 0b0000000000000001) {

        ssd1306_DrawString("Error: No TC", 2, 40);

        temp = 0;

        temp_frac = 0;

    }

    else 

    {

        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 

        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) 

    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)

    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);

            GPIO_SetBits(SSR_PIN);

            last_ssr_on = ticks;

        }

    }

    // Kill SSR after elapsed period less than SSR_PERIOD 

    if(ticks - last_ssr_on > ssr_output || ssr_output == 0)

    {

        GPIO_ResetBits(LED_STAT);

        GPIO_ResetBits(SSR_PIN);

    }

}

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 	0x001C

#define EEPROM_ADDR_BOOTTOBREW		0x0020

#define EEPROM_ADDR_K_P			0x0024

#define EEPROM_ADDR_K_I			0x0028

#define EEPROM_ADDR_K_D			0x002C

#define EEPROM_ADDR_BREWTEMP		0x0030

#define EEPROM_ADDR_STEAMTEMP		0x0034

#define EEPROM_BASE_ADDR    0x08080000    

#define EEPROM_BYTE_SIZE    0x0FFF  

void Minimal_EEPROM_Unlock(void)

{

  if((FLASH->PECR & FLASH_PECR_PELOCK) != RESET)

  {

    /* Unlocking the Data memory and FLASH_PECR register access*/

    FLASH->PEKEYR = FLASH_PEKEY1;

    FLASH->PEKEYR = FLASH_PEKEY2;

  }

}

void Minimal_EEPROM_Lock(void)

{

  /* Set the PELOCK Bit to lock the data memory and FLASH_PECR register access */

  FLASH->PECR |= FLASH_PECR_PELOCK;

}

FLASH_Status Minimal_FLASH_GetStatus(void)

{

  FLASH_Status FLASHstatus = FLASH_COMPLETE;

  if((FLASH->SR & FLASH_FLAG_BSY) == FLASH_FLAG_BSY)

  {

    FLASHstatus = FLASH_BUSY;

  }

  else

  {

    if((FLASH->SR & (uint32_t)FLASH_FLAG_WRPERR)!= (uint32_t)0x00)

    {

      FLASHstatus = FLASH_ERROR_WRP;

    }

    else

    {

      if((FLASH->SR & (uint32_t)0x1E00) != (uint32_t)0x00)

      {

        FLASHstatus = FLASH_ERROR_PROGRAM;

      }

      else

      {

        FLASHstatus = FLASH_COMPLETE;

      }

    }

  }

  /* Return the FLASH Status */

  return FLASHstatus;

}

FLASH_Status Minimal_FLASH_WaitForLastOperation(uint32_t Timeout)

{

  __IO FLASH_Status status = FLASH_COMPLETE;

  /* Check for the FLASH Status */

  status = Minimal_FLASH_GetStatus();

  /* Wait for a FLASH operation to complete or a TIMEOUT to occur */

  while((status == FLASH_BUSY) && (Timeout != 0x00))

  {

    status = Minimal_FLASH_GetStatus();

    Timeout--;

  }

  if(Timeout == 0x00 )

  {

    status = FLASH_TIMEOUT;

  }

  /* Return the operation status */

  return status;

}

void Minimal_EEPROM_ProgramWord(uint32_t Address, uint32_t Data)

{

  // Wait for last operation to be completed 

  FLASH_Status status = FLASH_COMPLETE;

  status = Minimal_FLASH_WaitForLastOperation(FLASH_ER_PRG_TIMEOUT);

  if(status == FLASH_COMPLETE)

  {

    *(__IO uint32_t *)Address = Data;

    // Wait for last operation to be completed 

    status = Minimal_FLASH_WaitForLastOperation(FLASH_ER_PRG_TIMEOUT);

  }

  // Return the Write Status 

  return status;

}

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_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: Save/restore temperature setpoint settings

void restore_settings()

{

    Minimal_EEPROM_Unlock();

    while(Minimal_FLASH_GetStatus()==FLASH_BUSY);

    while(Minimal_FLASH_GetStatus()==FLASH_BUSY);

    while(Minimal_FLASH_GetStatus()==FLASH_BUSY);

    while(Minimal_FLASH_GetStatus()==FLASH_BUSY);

    while(Minimal_FLASH_GetStatus()==FLASH_BUSY);

    while(Minimal_FLASH_GetStatus()==FLASH_BUSY);

    while(Minimal_FLASH_GetStatus()==FLASH_BUSY);

    Minimal_EEPROM_Lock();

}

void user_input(uint16_t* to_modify)

{

    if(CHANGE_ELAPSED) {

        // TODO: Make function that takes reference to a var and increase/decreases it based on buttonpress

        if(!GPIO_ReadInputDataBit(SW_UP) ) {

            CHANGE_RESET;

            (*to_modify)++;

        }

        else if(!GPIO_ReadInputDataBit(SW_DOWN) && (*to_modify) > 0) {

            CHANGE_RESET;

            (*to_modify)--;

        }

    }

}

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);

            ssd1306_DrawString(tempstr, 3, 72);

            ssd1306_drawlogo();

            switch(goto_mode) {

                case 2:

                {

                    ssd1306_DrawString("-> brew     ", 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:

                        state = STATE_IDLE;

                        break;

                    default:

                        state = STATE_PREHEAT_BREW;

                }

            }

            else if(SW_UP_PRESSED && goto_mode < 2) {

                goto_mode++;

            }

            else if(SW_DOWN_PRESSED && k_p > 0 && 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);

            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);

            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);

            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_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) {

                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("Boot to Brew", 0, 40);

            ssd1306_drawlogo();

            ssd1306_DrawString("btb=", 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) {

                save_settings();

                state = STATE_IDLE;

            }

            else if(!GPIO_ReadInputDataBit(SW_UP)) {

                boottobrew = 1;

            }

            else if(!GPIO_ReadInputDataBit(SW_DOWN)) {

                boottobrew = 0;

            }

            // 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;

	    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("Ready to Brew!", 0, 40);

            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, 40);

            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, 40);

            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;

        // 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;

}