#include "main.h"
#include "stm32l100c_discovery.h"
#include "ssd1306.h"

// USB includes
#include "hw_config.h"
#include "usb_lib.h"
#include "usb_desc.h"
#include "usb_pwr.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

// TODO: Grab buttonpresses with interrupts
// TODO: Eliminate screen buffer since we aren't using it...
#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

// 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_PREHEAT_BREW,
    STATE_MAINTAIN_BREW,
    STATE_PREHEAT_STEAM,
    STATE_MAINTAIN_STEAM,
};


char* itoa(int16_t i, char b[]){
    char const digit[] = "0123456789";
    char* p = b;
    if(i<0){
        *p++ = '-';
        i *= -1;
    }
    uint16_t shifter = i;
    do{ //Move to where representation ends
        ++p;
        shifter = shifter/10;
    }while(shifter);
    *p = '\0';
    do{ //Move back, inserting digits as you go
        *--p = digit[i%10];
        i = i/10;
    }while(i);
    return b;
}

char* itoa_fp(int16_t i, uint8_t frac, char b[]){
    char const digit[] = "0123456789";

    // set p to beginning of char array
    char* p = b;

    // If negative, set current char to '-' and inc, unnegate number
    if(i<0){
        *p++ = '-';
        i *= -1;
    }

    // Init shifter to numeric value
    uint16_t shifter = i;
    uint16_t frac_shifter = frac;

    // Iterate through 10s places, incrementing text pointer as we go
    do{ 
        ++p;
        shifter = shifter/10;
    }while(shifter);
    
    ++p; // increment for decimal point

    do{
        ++p;
        frac_shifter = frac_shifter/10;
    }while(frac_shifter);
        

    // Null-terminate the string
    *p = '\0';

    // Go backwards and write out fractional digits 
    do{ 
        *--p = digit[frac%10];
        frac = frac/10;
    }while(frac);

    *--p = '.'; // insert decimal point

    // Go backwards and write out remaining digits 
    do{ 
        *--p = digit[i%10];
        i = i/10;
    }while(i);
    return b;
}


static __IO uint32_t TimingDelay;

// Move to header file
void init_gpio();
void init_spi();
void process();
void machine();

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)
    // TODO: PWM of stat led (TIM3_CH2)

    // 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_block_write();

    // Startup screen 
    ssd1306_DrawString("therm v0.1", 1, 40);
    ssd1306_DrawString("protofusion.org/therm", 3, 0);
    Delay(1500);
    ssd1306_block_write();

    // 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);
}

uint32_t ticks = 0;
uint32_t last_ssr_on = 0;
uint32_t last_led = 0;
int32_t setpoint = 0;
uint16_t k_p = 1;
uint16_t k_i = 1;
uint16_t k_d = 1;
uint8_t ssr_output = 0; // Duty cycle of ssr, 0 to SSR_PERIOD 

// 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
    if(ticks - last_ssr_on > SSR_PERIOD)
    {
        GPIO_SetBits(LED_STAT);
        last_ssr_on = ticks;
    }
    
    // Kill SSR after elapsed period less than SSR_PERIOD 
    if(ticks - last_ssr_on > ssr_output || !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 state = STATE_IDLE;
uint8_t goto_mode = 2;

// State machine
void machine()
{
    uint8_t last_state = state;

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

            char tempstr[6];
            itoa_fp(temp, temp_frac, tempstr);
            ssd1306_DrawString("Temp: ", 3, 40);
            ssd1306_DrawString("    ", 3, 70);
            ssd1306_DrawString(tempstr, 3, 72);

            ssd1306_drawlogo();

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

                case 1:
                {
                    ssd1306_DrawString("-> set P/I/D", 1, 40);
                } break;

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

            // Button handler
            if(!GPIO_ReadInputDataBit(SW_BTN)) {
                switch(goto_mode) {
                    case 2:
                        state = STATE_PREHEAT_BREW;
                        break;
                    case 1:
                        state = STATE_SETP;
                        break;
                    case 0:
                        state = STATE_SETP;
                        break;
                    default:
                        state = STATE_PREHEAT_BREW;
                }
            }
            else if(!GPIO_ReadInputDataBit(SW_UP) && goto_mode < 2) {
                goto_mode++;
            }
            else if(!GPIO_ReadInputDataBit(SW_DOWN) && 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);

            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(!GPIO_ReadInputDataBit(SW_BTN)) {
                state = STATE_SETI;
            }
            else if(!GPIO_ReadInputDataBit(SW_UP)) {
                k_p++;
            }
            else if(!GPIO_ReadInputDataBit(SW_DOWN) && k_p > 0) {
                k_p--;
            }

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

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

            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(!GPIO_ReadInputDataBit(SW_BTN)) {
                state = STATE_SETD;
            }
            else if(!GPIO_ReadInputDataBit(SW_UP)) {
                k_i++;
            }
            else if(!GPIO_ReadInputDataBit(SW_DOWN) && k_i > 0) {
                k_i--;
            }


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

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

            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(!GPIO_ReadInputDataBit(SW_BTN)) {
                state = STATE_IDLE;
            }
            else if(!GPIO_ReadInputDataBit(SW_UP)) {
                k_d++;
            }
            else if(!GPIO_ReadInputDataBit(SW_DOWN) && k_d > 0) {
                k_d--;
            }

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

        case STATE_PREHEAT_BREW:
        {
            // Write text to OLED
            // [ therm : preheating brew ]
            // [ 30 => 120 C             ]
            ssd1306_DrawString("Preheating...", 0, 40);
            draw_setpoint();

            // Button handler
            if(!GPIO_ReadInputDataBit(SW_BTN)) {
                state = STATE_IDLE;
            }

            // 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);
            draw_setpoint();

            // Button handler
            if(!GPIO_ReadInputDataBit(SW_BTN)) {
                state = STATE_IDLE;
            }

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

        case STATE_PREHEAT_STEAM:
        {
            // Write text to OLED
            // [ therm : preheating steam ]
            // [ 30 => 120 C           ]
            ssd1306_DrawString("Preheating...", 0, 40);
            draw_setpoint();

            // Button handler
            if(!GPIO_ReadInputDataBit(SW_BTN)) {
                state = STATE_IDLE;
            }

            // 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);
            draw_setpoint();

            // Button handler
            if(!GPIO_ReadInputDataBit(SW_BTN)) {
                state = STATE_IDLE;
            }

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

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

        } break;
            
    }

    if(last_state != state) {
        // Clear screen on state change
        ssd1306_block_write();
    }
}


/**
  * @brief  Inserts a delay time.
  * @param  nTime: specifies the delay time length, in 1 ms.
  * @retval None
  */
void Delay(__IO uint32_t nTime)
{
  TimingDelay = nTime;
  while(TimingDelay != 0);
}


/**
  * @brief  Decrements the TimingDelay variable.
  * @param  None
  * @retval None
  */
void TimingDelay_Decrement(void)
{
  if (TimingDelay != 0x00)
  { 
    TimingDelay--;
  }
  ticks++;
}


void init_spi(void)
{
    SPI_InitTypeDef  SPI_InitStructure;

    // OLED IC
    SPI_Cmd(SPI1, DISABLE); 
    SPI_InitStructure.SPI_Direction = SPI_Direction_1Line_Tx;
    SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
    SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
    SPI_InitStructure.SPI_CPOL = SPI_CPOL_High;
    SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;
    SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
    SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_4;
    SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
    SPI_InitStructure.SPI_CRCPolynomial = 7;
    SPI_Init(SPI1, &SPI_InitStructure);
    SPI_Cmd(SPI1, ENABLE);           /* Enable the SPI  */   


    // MAX IC
    SPI_Cmd(SPI2, DISABLE); 
    SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
    SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
    SPI_InitStructure.SPI_DataSize = SPI_DataSize_16b; // Andysworkshop
    SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low; // From andysworkshop
    SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge; // same
    SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
    SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_8;
    SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
    SPI_InitStructure.SPI_CRCPolynomial = 7;
    SPI_Init(SPI2, &SPI_InitStructure);
    SPI_Cmd(SPI2, ENABLE);           /* Enable the SPI */
}

void init_gpio(void) {

 GPIO_InitTypeDef GPIO_InitStruct;

  // Enable SPI clocks
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2, ENABLE);

  // Enable GPIO clocks
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOC|RCC_AHBPeriph_GPIOB|RCC_AHBPeriph_GPIOA, ENABLE);

  // Enable DMA clocks (Is AHB even the right thing???)
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE); // EMZ TODO get the right ones

  /*Configure GPIO pin : PC */
  GPIO_InitStruct.GPIO_Pin = GPIO_Pin_13;
  GPIO_InitStruct.GPIO_Mode = GPIO_Mode_OUT;
  GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_InitStruct.GPIO_Speed = GPIO_Speed_400KHz;
  GPIO_Init(GPIOC, &GPIO_InitStruct);

  /*Configure GPIO pin : PB */
  GPIO_InitStruct.GPIO_Pin = GPIO_Pin_1|GPIO_Pin_2|GPIO_Pin_10|GPIO_Pin_12 
                          |GPIO_Pin_9;
  GPIO_InitStruct.GPIO_Mode = GPIO_Mode_OUT;
  GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_InitStruct.GPIO_Speed = GPIO_Speed_400KHz;
  GPIO_Init(GPIOB, &GPIO_InitStruct);

  /*Configure GPIO pin : PA */
  GPIO_InitStruct.GPIO_Pin = GPIO_Pin_15;
  GPIO_InitStruct.GPIO_Mode = GPIO_Mode_OUT;
  GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_InitStruct.GPIO_Speed = GPIO_Speed_400KHz;
  GPIO_Init(GPIOA, &GPIO_InitStruct);

  /*Configure GPIO pin : PB */
  GPIO_InitStruct.GPIO_Pin = GPIO_Pin_3|GPIO_Pin_4|GPIO_Pin_5|GPIO_Pin_6 
                          |GPIO_Pin_7;
  GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN;
  GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_Init(GPIOB, &GPIO_InitStruct);

  /** SPI1 GPIO Configuration  
  PA5   ------> SPI1_SCK
  PA7   ------> SPI1_MOSI
  */

  /*Enable or disable the AHB peripheral clock */
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);

  /*Configure GPIO pin : PA: MOSI,SCK */
  GPIO_InitStruct.GPIO_Pin = GPIO_Pin_5|GPIO_Pin_7;
  GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_InitStruct.GPIO_Speed = GPIO_Speed_10MHz;
  GPIO_Init(GPIOA, &GPIO_InitStruct);

  /*Configure GPIO pin alternate function */
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_SPI1);

  /*Configure GPIO pin alternate function */
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_SPI1);

  /** SPI2 GPIO Configuration  
  PB13   ------> SPI2_SCK
  PB14   ------> SPI2_MISO
  PB15   ------> SPI2_MOSI
  */

  /*Enable or disable the AHB peripheral clock */
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE);

// SPI PINSSS

  /*Configure GPIO pin : PB, MOSI, SCK */
  GPIO_InitStruct.GPIO_Pin = GPIO_Pin_13|GPIO_Pin_15;
  GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_InitStruct.GPIO_Speed = GPIO_Speed_10MHz;
  GPIO_Init(GPIOB, &GPIO_InitStruct);

 GPIO_InitTypeDef GPIO_InitStruct2;
// MISO
  GPIO_InitStruct2.GPIO_Pin = GPIO_Pin_14;
  GPIO_InitStruct2.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStruct2.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_InitStruct2.GPIO_Speed = GPIO_Speed_10MHz;
  GPIO_Init(GPIOB, &GPIO_InitStruct2);


  //Configure GPIO pin alternate function 
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource13, GPIO_AF_SPI2);
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource14, GPIO_AF_SPI2);
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource15, GPIO_AF_SPI2);


  /** USB GPIO Configuration  
  PA11   ------> USB_DM
  PA12   ------> USB_DP
  */

  /*Enable or disable the AHB peripheral clock */
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);

  /*Configure GPIO pin : PA */
  GPIO_InitStruct.GPIO_Pin = GPIO_Pin_11|GPIO_Pin_12;
  GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_InitStruct.GPIO_Speed = GPIO_Speed_400KHz;
  GPIO_Init(GPIOA, &GPIO_InitStruct);
}

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