/*
 * File:   nachtlicht.c
 * Author: joachim
 *
 * Created on 07. November 2025
 */

//This uses PIC12F509
//MPLAB X IDE
//XC8 C compiler (free)

/*------------------------------< Includes >----------------------------------*/
#include <xc.h>
#include <stdint.h>

/*------------------------------< Defines >-----------------------------------*/
#define  _XTAL_FREQ 4000000
#define   LED_HEAD  GPIObits.GP0   //active low
#define   LED_FLOOD GPIObits.GP1   //active low
#define   INP_AMB   GPIObits.GP2   //active high
#define   INP_MAINS GPIObits.GP3   //active low
#define   INP_SW    GPIObits.GP4   //active low
#define   INP_SENS  GPIObits.GP5   //active low

#define   WAITTIME_SW    50    // 0-255
#define   WAITTIME_MOVE  10    // 0-255
#define   WAITTIME_MAINS 100   // 0-255
#define   ONTIME_LED     3000  // 0-65535
#define   ON             1
#define   OFF            0
#define   LED_ON         0
#define   LED_OFF        1     


/*------------------------------< Typedefs >----------------------------------*/


/*------------------------------< Constants >---------------------------------*/


/*------------------------------< Compiler pragmas >--------------------------*/
#pragma config OSC = IntRC      // Oscillator Selection bits (external RC oscillator)
#pragma config WDT = ON         // Watchdog Timer Enable bit (WDT disabled)
#pragma config CP = OFF         // Code Protection bit (Code protection off)
#pragma config MCLRE = OFF       // GPIObits.GP3/MCLR Pin Function Select bit (GPIObits.GP3/MCLR pin function is MCLR)


/*------------------------------< Variables >---------------------------------*/
uint8_t switch_pressed;
uint8_t mains_down;
uint8_t move_detected;
uint8_t switch_state = 1;
uint16_t timer_light;

/*------------------------------< Prototypes >--------------------------------*/


/*------------------------------< Macros >------------------------------------*/


/*------------------------------< Functions >---------------------------------*/

/*-------------------------------------------------------------------------*//*!
  \fn        setLight(uint8_t on_off)

  \brief     sets light on/off depending on current state

  \param     on_off

  \return    -

  \remarks   -
*//*--------------------------------------------------------------------------*/
void setLight(uint8_t on_off) {
    if (on_off) {
        switch (switch_state) {
            case 1:
                LED_HEAD = LED_OFF;
                LED_FLOOD = LED_ON;
                break;

            case 2:
                LED_HEAD = LED_ON;
                LED_FLOOD = LED_OFF;
                break;
                
            case 0:
            default:
                LED_HEAD = LED_OFF;
                LED_FLOOD = LED_OFF;
                break;
        }
    } else {
        LED_HEAD = LED_OFF;
        LED_FLOOD = LED_OFF;
    }
}

/*-------------------------------------------------------------------------*//*!
  \fn        detectSwitch(void)

  \brief     detect pressed switch

  \param     -

  \return    -

  \remarks   -
*//*--------------------------------------------------------------------------*/
void detectSwitch(void) {
    static uint8_t count_sw;
    
    if (INP_SW == 0) {
        if (count_sw > WAITTIME_SW) {
            switch_pressed = 1;
            count_sw = 0;
        } else {
            ++count_sw;
        }
    } else {
        count_sw = 0;
    }

}


/*-------------------------------------------------------------------------*//*!
  \fn        detectMove(void)

  \brief     detect signal from PIR detector

  \param     -

  \return    -

  \remarks   -
*//*--------------------------------------------------------------------------*/
void detectMove(void)
{
    static uint8_t count_led;

    if (INP_AMB == 1 && INP_SENS == 0) {
        if (count_led > WAITTIME_MOVE) {
            move_detected = 1;
        } else {
            ++count_led;
        } 
    }
    else
    {
        count_led     = 0;
        move_detected = 0;
    }
}


/*-------------------------------------------------------------------------*//*!
  \fn        detectMains(void)

  \brief     detect mains off

  \param     -

  \return    -

  \remarks   -
*//*--------------------------------------------------------------------------*/
void detectMains(void) {
    static uint8_t count_mains;;
    
    if (INP_MAINS == 1) {
        if (count_mains > WAITTIME_MAINS) {
            mains_down = 1;
        } else {
            ++count_mains;
        }
    } else {
        count_mains = 0;
        mains_down  = 0;
    }

}


/*-------------------------------------------------------------------------*//*!
  \fn        main(void)

  \brief     main loop

  \param     -

  \return    -

  \remarks   -
*//*--------------------------------------------------------------------------*/
void main(void) {
    /*OPTION
     * bit 7 GPWU: Enable Wake-up on Pin Change bit (GP0, GP1, GP3)
     *      1 = Disabled
     *      0 = Enabled
     * bit 6 GPPU: Enable Weak Pull-ups bit (GP0, GP1, GP3)
     *      1 = Disabled
     *      0 = Enabled
     * bit 5 T0CS: Timer0 Clock Source Select bit
     *      1 = Transition on T0CKI pin (overrides TRIS on the T0CKI pin)
     *      0 = Transition on internal instruction cycle clock, FOSC /4
     * bit 4 T0SE: Timer0 Source Edge Select bit
     *      1 = Increment on high-to-low transition on the T0CKI pin
     *      0 = Increment on low-to-high transition on the T0CKI pin
     * bit 3 PSA: Prescaler Assignment bit
     *      1 = Prescaler assigned to the WDT
     *      0 = Prescaler assigned to Timer0
     * bit 2-0 PS<2:0>: Prescaler Rate Select bits
     *   Bit Value  Timer0 Rate WDT Rate
     *      000     1 : 2       1 : 1
     *      001     1 : 4       1 : 2
     *      010     1 : 8       1 : 4
     *      011     1 : 16      1 : 8
     *      100     1 : 32      1 : 16
     *      101     1 : 64      1 : 32
     *      110     1 : 128     1 : 64
     *      111     1 : 256     1 : 128
    */
    
    OPTION   = 0x87;
    
    /* TRISGPIO = 00111100
     * Configured GP0 and GP1 as output, all others input
     * (GP3 is always input)
    */
    TRISGPIO = 0x3C;
    
    // Set output pins to LED off state
    GPIObits.GP0 = LED_OFF;
    GPIObits.GP1 = LED_OFF;

    while (1) {
        CLRWDT();
        __delay_ms(10);
        
        detectSwitch();

        if (switch_pressed) {
            ++switch_state;
            if (switch_state > 2) {
                switch_state = 0;
            }
            switch_pressed=0;
        }

        detectMains();
                
        if (mains_down) {
            setLight(ON);
        } else {
            detectMove();

            if (move_detected) {
                timer_light =  ONTIME_LED;
            }
            
           if(timer_light > 0){
                --timer_light;
                setLight(ON);
            }else{
                setLight(OFF);
            }
            
        }
    }
}