/**
 * @file safety.h
 * @brief Safety monitoring for temperature sensors.
 *
 * This module performs sanity checks on all temperature sensors and
 * puts the system into a safe state if any sensor fails.
 */

#pragma once

#include "outputs.h"
#include "inputs.h"

#include "sdkconfig.h"
#include "esp_err.h"

#include <stdint.h>

/** @brief Maximum length of sensor name string. */
#define MAX_ERROR_STRING_SIZE 64U

/** @brief Number of sensors to monitor. */
#define NUMBER_OF_SENSOR_SANITY_CHECKS 4U

/** @brief Chamber sensor maximum temperature limit (°C). */
#define SENSOR_LIMIT_CHAMBER_MAX (CONFIG_SENSOR_LIMIT_CHAMBER_MAX / 10.0f)

/** @brief Chamber sensor minimum temperature limit (°C). */
#define SENSOR_LIMIT_CHAMBER_MIN (CONFIG_SENSOR_LIMIT_CHAMBER_MIN / 10.0f)

/** @brief Outdoor sensor maximum temperature limit (°C). */
#define SENSOR_LIMIT_OUTDOOR_MAX (CONFIG_SENSOR_LIMIT_OUTDOOR_MAX / 10.0f)

/** @brief Outdoor sensor minimum temperature limit (°C). */
#define SENSOR_LIMIT_OUTDOOR_MIN (CONFIG_SENSOR_LIMIT_OUTDOOR_MIN / 10.0f)

/** @brief Inlet flow sensor maximum temperature limit (°C). */
#define SENSOR_LIMIT_INLET_MAX (CONFIG_SENSOR_LIMIT_INLET_MAX / 10.0f)

/** @brief Inlet flow sensor minimum temperature limit (°C). */
#define SENSOR_LIMIT_INLET_MIN (CONFIG_SENSOR_LIMIT_INLET_MIN / 10.0f)

/** @brief Return flow sensor maximum temperature limit (°C). */
#define SENSOR_LIMIT_RETURN_MAX (CONFIG_SENSOR_LIMIT_RETURN_MAX / 10.0f)

/** @brief Return flow sensor minimum temperature limit (°C). */
#define SENSOR_LIMIT_RETURN_MIN (CONFIG_SENSOR_LIMIT_RETURN_MIN / 10.0f)

/**
 * @brief Sensor error state enumeration.
 */
typedef enum _SensorErrorState
{
    SENSOR_NO_ERROR,  /**< Sensor operating normally. */
    SENSOR_TOO_HIGH,  /**< Temperature above maximum limit. */
    SENSOR_TOO_LOW,   /**< Temperature below minimum limit. */
    SENSOR_UNCHANGED, /**< Temperature unchanged for too long. */
    SENSOR_NOT_FOUND  /**< Sensor not responding. */
} eSensorErrorState;

/**
 * @brief Overall safety state enumeration.
 */
typedef enum _SafetyState
{
    SAFETY_NO_ERROR,      /**< All sensors OK. */
    SAFETY_SENSOR_ERROR,  /**< At least one sensor failed. */
    SAFETY_INTERNAL_ERROR /**< Internal module error. */
} eSafetyState;

/**
 * @brief Function pointer type for sensor getter functions.
 */
typedef sMeasurement (*GetSensorValue)();

/**
 * @brief Temperature sensor limits.
 */
typedef struct _TemperatureSensorLimit
{
    float max; /**< Maximum temperature limit. */
    float min; /**< Minimum temperature limit. */
} sTemperatureSensorLimit;

/**
 * @brief Sensor sanity check state structure.
 */
typedef struct _SensorSanityCheck
{
    eSensorErrorState state;              /**< Current error state. */
    char name[MAX_ERROR_STRING_SIZE];     /**< Sensor name for logging. */
    sTemperatureSensorLimit sSensorLimit; /**< Temperature limits. */
    float fSensorTemperatureLast;         /**< Last temperature reading. */
    uint32_t uUnchangedCounter;           /**< Counter for unchanged readings. */
    GetSensorValue getSensor;             /**< Function to get sensor value. */
} sSensorSanityCheck;

/**
 * @brief Initialize the safety module.
 *
 * Creates the safety monitoring task and sets initial safe state.
 *
 * @return ESP_OK on success, ESP_FAIL on error.
 */
esp_err_t initSafety(void);

/**
 * @brief Get the current sensor sanity states.
 * @param[out] pSensorSanityChecks Array to receive sensor states.
 */
void getSensorSanityStates(sSensorSanityCheck *pSensorSanityChecks);

/**
 * @brief Get the overall safety state.
 * @return eSafetyState indicating current safety status.
 */
eSafetyState getSafetyState(void);