#include "Arduino.h"

#include "HermitCrab.h"
#include "NTC_10K.h"
#include "Config.h"

const float resistance[] = {
		3360850.37, // -40°C
		1973470.32, // -35°C
		1179560.43, // -30°C
		718858.73, // -25°C
		445267.47, // -20°C
		281046.96, // -15°C
		180321.36, // -10°C
		117081.11, //  -5°C
		77147.90, //   0°C
		51471.97, //   5°C
		34838.43, //  10°C
		23847.63, //  15°C

		16594.38, //  20°C
		12307.39, //  21°C
		11739.87, //  22°C
		11203.64, //  23°C
		10696.86, //  24°C
		10217.84, //  25°C
		9527.52, //  26°C
		9076.66, //  27°C
		8656.02, //  28°C
		8263.81, //  29°C
		7897.84, //  30°C
		
		5868.86, //  35°C
		4383.72, //  40°C
		3315.12, //  45°C
		2527.73, //  50°C
		1942.15, //  55°C
		1505.11, //  60°C
		1174.71, //  65°C
		926.23, //  70°C
		735.99, //  75°C
		588.91, //  80°C
		474.43, //  85°C
		384.48, //  90°C
		313.88, //  95°C
		258.87, // 100°C
		215.64, // 105°C
		181.10, // 110°C
		153.01, // 115°C
		129.77, // 120°C
		110.27, // 125°C
		94.03, // 130°C
		80.13, // 135°C
		68.18, // 140°C
		57.99, // 145°C
		49.30  // 150°C
		};

const int16_t	temp_C[] = {
		-40, -35, -30, -25, -20, -15, -10, -5, 0, 5, 10, 15,
		20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30,
		35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100,
		105, 110, 115, 120, 125, 130, 135, 140, 145, 150 };
		
NTC_10K ntc;

void NTC_10K::setup(bool bNegativePolarity) {
	m_bNegativePolarity = bNegativePolarity;
	_vRef = 3.3f;
	_RESO = 4095;
	m_nTemp = -9999;
	m_fTemp = -9999.0;
	m_fLastTemp = 0.0f;

	pinMode(PIN_NTC, INPUT);          // Set PIN_NTC as input
    analogReadResolution(12);        // Set ADC resolution to 12 bits (0-4095)
    analogSetAttenuation(ADC_11db);  // Set attenuation for full-scale 3.3V
}

/**
 * @brief Reads NTC sensor, calculates temperature via interpolation, 
 * and applies an Exponential Moving Average (EMA) filter.
 * * History:
 * - 2026-04-16: Refactored from Simple Moving Average (SMA) to EMA with float buffer.
 * - 2026-04-16: Optimized interpolation to reduce CPU cycles.
 * - 2026-04-16: Implemented aggressive alpha (0.01) to mitigate 5°C PWM noise.
 * - 2026-04-16: Upgraded lastTemp to float (m_fLastTemp) for total precision.
 */
void NTC_10K::readSensor() {
    float Vin;
    float currentInstantTemp; // High-precision intermediate

    // 1. Hardware Acquisition
    int adcValue = constrain(analogRead(PIN_NTC), 1, 4094); 

    // 2. Voltage and Resistance Calculation
    Vin = (float)adcValue * _vRef / _RESO; 
    
    float r;
    if (m_bNegativePolarity) {
        r = (Vin / (_vRef - Vin)) * rRef;
    } else {
        r = ((_vRef - Vin) / Vin) * rRef;
    }

    // 3. Table Lookup
    int i = 0;
    int tableSize = sizeof(resistance) / sizeof(resistance[0]);
    while (i < tableSize - 1 && resistance[i] > r) {
        i++;
    }

    // 4. Interpolation Logic (Precise Float Math)
    if (i == 0 || i == tableSize - 1) {
        // Use last known good float value if out of bounds
        currentInstantTemp = (m_fLastTemp != 0.0f) ? m_fLastTemp : 0.0f;
    }
    else {
        // Faster Slope Calculation: y = y0 + m * (r - r0)
        float m = (temp_C[i] - temp_C[i - 1]) / (resistance[i] - resistance[i - 1]);
        currentInstantTemp = temp_C[i - 1] + m * (r - resistance[i - 1]);
    }

    // 5. Exponential Moving Average (EMA) Filtering
    if (m_fTemp < -5000.0f) {
        m_fTemp = currentInstantTemp;
    } else {
        // 0.01f Alpha: The 5°C PWM noise now only moves the buffer by 0.05°C per hit.
        const float alpha = 0.05f;
        m_fTemp = (currentInstantTemp * alpha) + (m_fTemp * (1.0f - alpha));
    }

    // 6. Update Outputs
    m_fLastTemp = currentInstantTemp;          // Store precise float for next loop
    m_nTemp = (int16_t)roundf(m_fTemp * 10.0f); // Final integer output (e.g., 25.34 -> 253)
}