/**
 * @file inputs.h
 * @brief Input handling for temperature sensors and burner fault detection.
 *
 * This module reads DS18B20 temperature sensors via 1-Wire and monitors
 * the burner fault input. It provides averaged, damped, and predicted
 * temperature values.
 */

#pragma once

#include "sdkconfig.h"

#include "esp_err.h"

#include <stddef.h>

/** @brief Returns the maximum of two values. */
#define MAX(a, b) ((a) > (b) ? (a) : (b))

/** @brief Initial value for measurements before first reading. */
#define INITIALISATION_VALUE 0.0f

/** @brief Sample buffer size for 10-second average. */
#define AVG10S_SAMPLE_SIZE 10U

/** @brief Sample buffer size for 60-second average. */
#define AVG60S_SAMPLE_SIZE 60U

/** @brief Sample buffer size for 24-hour average. */
#define AVG24H_SAMPLE_SIZE 24U

/** @brief Sample buffer size for 60-second prediction. */
#define PRED60S_SAMPLE_SIZE 60U

/** @brief Damping factor for rising temperatures (from Kconfig). */
#define DAMPING_FACTOR_WARMER (CONFIG_DAMPING_FACTOR_WARMER * 0.00001f)

/** @brief Damping factor for falling temperatures (from Kconfig). */
#define DAMPING_FACTOR_COLDER (CONFIG_DAMPING_FACTOR_COLDER * 0.00001f)

/**
 * @brief Burner error state enumeration.
 */
typedef enum _BurnerErrorState
{
    NO_ERROR, /**< No burner fault detected. */
    FAULT     /**< Burner fault signal active. */
} eBurnerErrorState;

/**
 * @brief Measurement error state enumeration.
 */
typedef enum _MeasurementErrorState
{
    MEASUREMENT_NO_ERROR, /**< Measurement valid. */
    MEASUREMENT_FAULT     /**< Measurement failed or sensor not found. */
} eMeasurementErrorState;

/**
 * @brief Circular buffer for averaging temperature values.
 */
typedef struct _Average
{
    float fValue;                                                                        /**< Current average value. */
    float samples[MAX(AVG10S_SAMPLE_SIZE, MAX(AVG60S_SAMPLE_SIZE, AVG24H_SAMPLE_SIZE))]; /**< Sample buffer. */
    size_t bufferIndex;                                                                  /**< Current write index. */
    size_t bufferCount;                                                                  /**< Number of valid samples. */
} sAverage;

/**
 * @brief Circular buffer for temperature prediction.
 */
typedef struct _Predict
{
    float fValue;                       /**< Predicted value. */
    float samples[PRED60S_SAMPLE_SIZE]; /**< Sample buffer. */
    size_t bufferIndex;                 /**< Current write index. */
    size_t bufferCount;                 /**< Number of valid samples. */
} sPredict;

/**
 * @brief Complete measurement data structure.
 */
typedef struct _Measurement
{
    float fCurrentValue;          /**< Current raw temperature value. */
    float fDampedValue;           /**< Damped temperature value. */
    sAverage average10s;          /**< 10-second rolling average. */
    sAverage average60s;          /**< 60-second rolling average. */
    sPredict predict60s;          /**< 60-second prediction. */
    eMeasurementErrorState state; /**< Measurement state. */
} sMeasurement;

/**
 * @brief Initialize the inputs module.
 *
 * Configures GPIO for burner fault input and starts the input task
 * for reading DS18B20 temperature sensors.
 *
 * @return ESP_OK on success, ESP_FAIL on error.
 */
esp_err_t initInputs(void);

/**
 * @brief Get the current chamber temperature measurement.
 * @return sMeasurement structure with current values and state.
 */
sMeasurement getChamberTemperature(void);

/**
 * @brief Get the current outdoor temperature measurement.
 * @return sMeasurement structure with current values and state.
 */
sMeasurement getOutdoorTemperature(void);

/**
 * @brief Get the current inlet flow temperature measurement.
 * @return sMeasurement structure with current values and state.
 */
sMeasurement getInletFlowTemperature(void);

/**
 * @brief Get the current return flow temperature measurement.
 * @return sMeasurement structure with current values and state.
 */
sMeasurement getReturnFlowTemperature(void);

/**
 * @brief Get the current burner error state.
 * @return eBurnerErrorState indicating fault status.
 */
eBurnerErrorState getBurnerError(void);