/*
 * Wemos d1 mini
 * Flash Size: 4M (1M SPIFFS)
 */

//Upload config: platformio run --target uploadfs

#include <Arduino.h>
#include <Homie.h>


#define FW_NAME "kuechenlicht"
#define FW_VERSION "1.0.0"

bool enableHandler(const HomieRange& range, const String& value);
bool fadetimeHandler(const HomieRange& range, const String& value);
bool brightnessHandler(const HomieRange& range, const String& value);
void loopHandler();

//#define DEBUG //turns on continuous serial debug printing


HomieNode lightNode("light", "Light", "light"); //paramters: topic, $name, $type



#define LED_PWM D5

#define BTN_A D7

#define PWM_MAX 1023 //10 bit dac
#define PWM_FREQUENCY 1000 //default: 1000 Hz

boolean enable=false;
float enable_fadevalue=0; //0=off, 1=on
float enable_fadevalue_change_per_loop=0.01; //fixed value. For manual calculatoin: enable_fadevalue_change_per_loop=_difference/fadetime*UPDATETIME;

float set_brightness=2; //0 to 1
#define BRIGHTNESS_MIN 0.0
#define BRIGHTNESS_MAX 2.0 //if temperature is in between both strips brightness of 2 means both are at full power. otherwise brightness will be clipped
#define BRIGHTNESSCURVE 1.4
float brightness=set_brightness;
float brightness_change_per_loop=0; //will be calculated by Handler


uint16_t fadetime=0; //0=instant. value is time in milliseconds
#define FADETIME_MIN 0
#define FADETIME_MAX 60000

long last_updatetime=0;
#define UPDATETIME 10 //after how many ms pwm values will be updated

//Button stuff
#define BUTTONUPDATETIME 20
long last_buttonupdatetime=0;
uint8_t btnAstate=0; //for button state machine
long btnAtime=0;
#define BTNHOLDTIME 1000

boolean holdDirection_brightness=false;

#define HOLDBRIGHTNESSCHANGE_PER_LOOP 0.01 //depends on BUTTONUPDATETIME. BUTTONUPDATETIME/1000/HOLDBRIGHTNESSCHANGE_PER_LOOP=seconds to change a full cycle(0 to 1)

boolean flag_updatePWM=false; //if manually set brightness or temperature, set this flag

//Debug
long last_debugupdatetime=0;
#define DEBUGUPDATETIME 500

//To check if values changed (for mqtt response)
boolean known_enable=!enable; //start with differend known values, actual values will be send first
float known_set_brightness=set_brightness+1;

void setup() {
  Serial.begin(115200);
  Serial.println("Hello");
  pinMode(LED_PWM, OUTPUT);
  analogWriteFreq(PWM_FREQUENCY);
  analogWrite(LED_PWM, PWM_MAX); //high = off

  pinMode(BTN_A, INPUT);

  Homie_setFirmware(FW_NAME, FW_VERSION);
  Homie_setBrand(FW_NAME);
  Homie.setLoopFunction(loopHandler);

  lightNode.advertise("brightness").settable(brightnessHandler);
  lightNode.advertise("fadetime").settable(fadetimeHandler);
  lightNode.advertise("enable").settable(enableHandler);
  

  Homie.setup();
}

void loop() {
  Homie.loop();  
}

void loopHandler() {
  long loopmillis=millis();

  

  if (loopmillis >= last_buttonupdatetime+BUTTONUPDATETIME ) {
    last_buttonupdatetime = loopmillis;


    // #### Button A ####
    boolean flag_btnApress=false; //short press on release
    boolean flag_btnAholdstart=false; //long press on start
    boolean flag_btnAhold=false; //long press after long press time
    boolean flag_btnAholdrelease=false; //long press on release
    
    if (digitalRead(BTN_A)) { //Button State Machine
      switch (btnAstate) {
        case 0: //was not pressed
          btnAstate=1;
          btnAtime=loopmillis; //start timer
        break;
        case 1: //was pressed last time checked
          if (loopmillis>btnAtime+BTNHOLDTIME) {
            btnAstate=2;
            flag_btnAholdstart=true;
          }
        break;
        case 2: //button hold time reached
          flag_btnAhold=true;
        break;
      }
    }else {
      if (btnAstate==1) { //short press
        btnAstate=0; //reset state
        flag_btnApress=true;
      }else if(btnAstate==2) { //long press released
        flag_btnAholdrelease=true;
        btnAstate=0; //reset state
      }
    }
    // #### END Button A Check ####

    

    //Button handling
    if (flag_btnApress){ //short press button
      enable = !enable; //switch on/off
      flag_updatePWM=true; //update pwm values
    }
    if (!enable && flag_btnAholdstart ) { //in not enabled and brightness button held down
      enable=true; //enable light
      set_brightness=0; //reset brightness
      brightness=set_brightness; //immediately
      holdDirection_brightness=true; //increase brightness
    } else if (enable) { //only change values if enabled
      // Button A Longpress Handling
      if (flag_btnAholdstart) {
        /*  //Change only hold direction at extremes
        if (set_brightness>=BRIGHTNESS_MAX) { //if hold started with brightness at one extreme
          holdDirection_brightness=false; //direction decrease
        }
        if (set_brightness<=BRIGHTNESS_MIN) { //if hold started with brightness at one extreme
          holdDirection_brightness=true; //direction increase
        }
        */
        holdDirection_brightness=!holdDirection_brightness; //change direction everytime
        
      }
      if (flag_btnAhold) { //brightness
        if (holdDirection_brightness) {
          set_brightness += HOLDBRIGHTNESSCHANGE_PER_LOOP;
        }else{
          set_brightness -= HOLDBRIGHTNESSCHANGE_PER_LOOP;  
        }
        set_brightness = constrain(set_brightness, BRIGHTNESS_MIN, BRIGHTNESS_MAX);
  
        brightness=set_brightness; //change immediately
        flag_updatePWM=true; //update pwm values
      }
      if (flag_btnAholdrelease) {
        
      }

    }

  }

  if (loopmillis >= last_updatetime+UPDATETIME ) {
    last_updatetime = loopmillis;

    
    float old_brightness = brightness; //store last brightness
    if ( (brightness_change_per_loop<0 && brightness>set_brightness) || (brightness_change_per_loop>0 && brightness<set_brightness)) { //if brightness not reached
      brightness += brightness_change_per_loop;
      if ( ( old_brightness <= set_brightness && set_brightness <= brightness ) || ( old_brightness >= set_brightness && set_brightness >= brightness ) ) { //overshot set value
        brightness = set_brightness;
      }
      flag_updatePWM=true; //force update
    }
    

    //Sleep
    if ( (!enable && enable_fadevalue>0) || (enable && enable_fadevalue<1) ) { //not fully turned off or on
      if (!enable) { //turn off
        enable_fadevalue-=enable_fadevalue_change_per_loop;
      }else{ //turn on
        enable_fadevalue+=enable_fadevalue_change_per_loop;
      }
      if (enable_fadevalue>1) { enable_fadevalue=1; } //limit
      if (enable_fadevalue<0) { enable_fadevalue=0; } //limit
      flag_updatePWM=true; //force update
    }

    //calculate and update pwm
    if (brightness != set_brightness || flag_updatePWM) { //if target not reached
      flag_updatePWM=false; // reset flag
      //calculate pwm values
      uint16_t pwm;
      pwm=pow((brightness*enable_fadevalue)/2.0, BRIGHTNESSCURVE)  *2.0 *PWM_MAX;  //calculate brightness for led stripe, scale to 0-1, ^2, rescale to 0-2, scale for pwm
      

      if (pwm>PWM_MAX) { pwm=PWM_MAX; } //limit

      analogWrite(LED_PWM, PWM_MAX-pwm); //full pwm is led off

    }
  }

  //send new values back to broker
  if (known_enable!=enable) { 
    lightNode.setProperty("enable").send(enable ? "true" : "false");
    known_enable=enable;
  }
  if (known_set_brightness!=set_brightness) { 
    lightNode.setProperty("brightness").send(String(set_brightness));
    known_set_brightness=set_brightness;
  }
  
  

  #ifdef DEBUG
  if (loopmillis >= last_debugupdatetime+DEBUGUPDATETIME ) {
    last_debugupdatetime = loopmillis;

    /*
    if (!enable) { Serial.print("not enable. "); }
    Serial.print("bright=");
    Serial.print(brightness);
    Serial.print(" set=");
    Serial.print(set_brightness);
    Serial.print("| temp=");
    Serial.print(temperature);
    Serial.print(" set=");
    Serial.print(set_temperature);
    Serial.print(" change=");
    Serial.print(brightness_change_per_loop);
    Serial.print(" enable_fadevalue=");
    Serial.println(enable_fadevalue);
    */
    

    
    uint16_t pwmCW;
    uint16_t pwmWW;
    float temp=mapFloat(temperature, TEMPERATURE_MIN, TEMPERATURE_MAX, 0.0,1.0); //0=warmwhite, 1=coldwhite
    pwmCW=pow((brightness*enable_fadevalue)*temp/2.0, 2)  *2.0 *PWM_MAX;  //calculate brightness for led stripe, scale to 0-1, ^2, rescale to 0-2, scale for pwm
    pwmWW=pow((brightness*enable_fadevalue)*(1-temp)/2.0, 2)  *2.0 *PWM_MAX;

    if (pwmCW>PWM_MAX) { pwmCW=PWM_MAX; } //limit
    if (pwmWW>PWM_MAX) { pwmWW=PWM_MAX; } //limit
    
    if (enable) {
      Serial.print("bright=");
      Serial.print(brightness);
      Serial.print(PWM_MAX-pwmWW);
      Serial.print(", ");
      Serial.println(PWM_MAX-pwmCW);
    }else{
      Serial.print("off");
      Serial.print(", ");
      Serial.println("off");
    }
    
    
  }
  #endif

}


bool brightnessHandler(const HomieRange& range, const String& value) {
  if (range.isRange) {
    return false; //if range is given but index is not in allowed range
  }
  Homie.getLogger() << "brightness " << ": " << value << endl;
  //lightNode.setProperty("brightness").send(value); //done in main loop
  if (value.toFloat() >= BRIGHTNESS_MIN && value.toFloat() <= BRIGHTNESS_MAX) {
    set_brightness=value.toFloat(); 
  }else {
    Homie.getLogger() << "Value outside range" << endl;
    return false;  
  }

  float _difference=set_brightness-brightness;
  if (fadetime>0) {
    brightness_change_per_loop = _difference/fadetime*UPDATETIME;
  } else { //special case for instant change
    brightness_change_per_loop = _difference;
  }
  
  return true;
}


bool fadetimeHandler(const HomieRange& range, const String& value) { //fadetime for temperature and brightness in milliseconds
  if (range.isRange) {
    return false; //if range is given but index is not in allowed range
  }
  Homie.getLogger() << "fadetime " << ": " << value << endl;
  lightNode.setProperty("fadetime").send(value);
  
  if (value.toInt() >= FADETIME_MIN && value.toInt() <= FADETIME_MAX) {
    fadetime=value.toInt(); 
  }else {
    Homie.getLogger() << "Value outside range" << endl;
    return false;  
  }
  
  return true;
}

bool enableHandler(const HomieRange& range, const String& value) { //change on off
  if (range.isRange) {
    return false; //if range is given but index is not in allowed range
  }
  Homie.getLogger() << "enable " << ": " << value << endl;
  //lightNode.setProperty("enable").send(value); //done in main loop
  
  if (value=="false") {
    enable=false;
  } else if(value=="true") {
    enable=true;
  } else {
    Homie.getLogger() << "Value outside range" << endl;
    return false;  
  }

  flag_updatePWM=true; //force update
  
  return true;
}

float mapFloat(float x, float in_min, float in_max, float out_min, float out_max) {
  return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}