#pragma once

#include <cstdint>

namespace kvida {

// Fine-grained channel identifiers, one per physical quantity a sensor can
// expose -- mirrors Zephyr's SENSOR_CHAN_* granularity so a single sensor
// (e.g. a BME280) can expose several channels from one fetch().
enum class SensorChannel {
    Contact,
    Motion,
    AmbientTemperature,
    Humidity,
    Pressure,
    AccelX,
    AccelY,
    AccelZ,
    Analog,
    PulseCount,
    Generic,
};

// Fixed-point value: actual value = val1 + val2 * 1e-6 (same convention as
// Zephyr's struct sensor_value). ESP32-C6 has no hardware FPU, so avoiding
// float/double here avoids paying for software-emulated floating point on
// every sample -- relevant given the battery-first design goal.
struct SensorValue {
    int32_t val1;
    int32_t val2;
    const char* unit;
    uint64_t timestamp_ms;
};

enum class SensorTriggerType {
    DataReady,
    Threshold,
};

// Plain function pointer + user_data, not std::function, to avoid heap
// allocation for callback storage on embedded targets.
using SensorTriggerHandler = void (*)(void* user_data);

class Sensor {
public:
    virtual ~Sensor() = default;

    virtual const char* id() const = 0;

    virtual void begin() = 0;

    // True if this sensor exposes the given channel. Lets `profiles`
    // discover capabilities generically instead of hardcoding per
    // concrete sensor.
    virtual bool supports(SensorChannel channel) const = 0;

    // Triggers a hardware read and caches the result internally. A
    // single fetch() may populate several channels at once (e.g. one
    // I2C transaction on a BME280 yields temperature + humidity +
    // pressure), so multi-channel sensors only pay the hardware cost
    // once per fetch(), not once per channel.
    virtual bool fetch() = 0;

    // Reads a previously fetched channel from the internal cache.
    // Returns false if the sensor doesn't support the channel, or if
    // fetch() hasn't been called yet.
    virtual bool get(SensorChannel channel, SensorValue& out) = 0;

    // Registers an interrupt-driven callback (data-ready pin, threshold
    // crossing, edge on a reed switch, ...) for sensors that support it.
    // Default: not supported: polling-only sensors don't override this.
    virtual bool set_trigger(SensorTriggerType type, SensorTriggerHandler handler, void* user_data)
    {
        (void)type;
        (void)handler;
        (void)user_data;
        return false;
    }
};

} // namespace kvida