#include "esphome.h"
    #include "SD.h"
    
    #define LOGFILENAME "plogger.csv"
    
    class powerLogger : public Component, public Sensor {
    public:
        /**
         * The constructor of the powerLogger class receives references for the current
         * and voltage sensors created by the INA219 integration and uses their internal
         * values to efficiently do the calculations
         *
         * @param int_dt    Internal deltaT, The minimum timestep for pooling the measurements
         * @param inaCurr   Current sensor reference, received through the id(SENSOR_ID)
         * @param inaColt   Voltage sensor reference, received through the id(SENSOR_ID)
         * @param ina       Actual Component reference, received through the id(COMPONENT_ID)
         * 
         */
        powerLogger(uint16_t int_dt, Sensor *inaCurr, Sensor *inaVolt, PollingComponent *ina) : 
            int_dt(int_dt), inaCurrent(inaCurr), inaVoltage(inaVolt), inaComp(ina) {}
        
        float get_setup_priority() const override { return esphome::setup_priority::DATA; }
        
        Sensor *capacity = new Sensor();
        Sensor *energy = new Sensor();
        Sensor *sdLog = new Sensor();
    
        uint16_t int_dt;
    
        Sensor *inaCurrent = nullptr;
        Sensor *inaVoltage = nullptr;
        PollingComponent *inaComp = nullptr;
    
        const int chipSelect = D8;  // used for ESP8266
        bool sdCardPresent = true;
    
        unsigned long last_measurement = 0;
        float net_mah = 0.0f;    
        float net_wh = 0.0f;
    
        float last_c = 0.0f;
        float last_v = 0.0f;
    
        void setup() override {
            ESP_LOGD("custom", "Sending hello from plogger");
            inaComp->update();
            last_c = getCurr();
            last_v = getVolt();
    
            if(!SD.begin(chipSelect)){
                sdCardPresent = false;
                ESP_LOGE("custom","SDCARD Initialization failed!");
            } else if (!SD.exists(LOGFILENAME)){
                File dataFile = SD.open(LOGFILENAME, FILE_WRITE);
                if(dataFile){ 
                    //Create the CSV header 
                    dataFile.println("Voltage,Current,Power,mAh,mWh,Dt");
                    dataFile.close();
                }
            }
    
            // Publish the SDCard presence so we can show it on the display
            sdLog->publish_state((int)sdCardPresent);
        }
    
        void loop() override {
            if(millis() > last_measurement + int_dt){
                inaComp->update();
                unsigned long dt = millis() - last_measurement;
                last_measurement += dt;
                float new_c = getCurr();
                float new_v = getVolt();
                
                //Integrate through the midpoint method
                float dmah = (((new_c - last_c)/2.0f)+last_c);
                if(dmah != 0.0f){ //Spare the calculations if value is zero
                    dmah *= ((float)dt/3600.0f); //convert our current uAs to mAh           
                    float dwh = (((new_v - last_v)/2.0f)+last_v)*dmah;
                    
                    net_mah += dmah;
                    net_wh += dwh;
                }
                
                ESP_LOGVV("custom", "mAh: %.5f || mWh: %.5f || Dt: %lu", net_mah, net_wh, dt);
                capacity->publish_state(net_mah);
                energy->publish_state(net_wh);
    
                last_c = new_c;
                last_v = new_v;
    
                if(sdCardPresent){
                    File dataFile = SD.open(LOGFILENAME, FILE_WRITE);
                    if(dataFile){     
                        // Write a new csv line to the sdcard
                        //             Voltage(V),Current(A),Power(W),mAh,mWh,Dt
                        dataFile.printf("%.3f,%.5f,%.4f,%.3f,%.3f,%lu\n",new_v, new_c, new_v*new_c, net_mah, net_wh, dt);
                        dataFile.close();
                    }else{
                        //if the file opening failed, disable sdcard altogether
                        sdCardPresent = false;
                        sdLog->publish_state((int)sdCardPresent);
                    }
                }
            }
        }
    
        //Helper functions to get the raw sensor data and do some filtering beforehand
        float getCurr(){
            float value = inaCurrent->raw_state;
            if(fabs(value) < 0.0002) value = 0.0;
            return value;
        }
    
        float getVolt(){
            float value = inaVoltage->raw_state;
            return value;
        }
    
        // In case we would need to reset the values without reseting the whole node
        void resetCapacity(){
            net_mah = 0.0f;
        }
    
        void resetEnergy(){
            net_wh = 0.0f;
        }
    };