camera_tuner.hpp

// camera_tuner.hpp
// Created by Greg on 10/10/2025.
// Copyright (C) 2025 Presage Security, Inc.
//
// SPDX-License-Identifier: LGPL-3.0-or-later
 
#pragma once
 
// standard library includes
#include <memory>
#include <cstdint>
 
// third-party includes
#include <absl/status/status.h>
#include <absl/status/statusor.h>
#include <physiology/modules/messages/status.h>
#include <mediapipe/framework/port/opencv_core_inc.h>
 
// local includes
#include "video_source.hpp"
#include "camera_tuner_settings.hpp"
 

 
namespace presage::smartspectra::video_source {

enum class TuningStage {
    NOT_STARTED,
    AUTO_WHITE_BALANCE,
    EXPOSURE_SEARCH,
    GAIN_SEARCH,
    COMPLETE,
    FAILED
};

class CameraTuner {
public:
    explicit CameraTuner(CameraTunerSettings settings = {});

    absl::Status SetVideoSource(std::shared_ptr<VideoSource> source);

    std::shared_ptr<VideoSource> GetVideoSource();

    absl::Status StartTuning();

    bool IsTuning() const;

    TuningStage GetCurrentStage() const;

    absl::Status ProcessFrame(presage::physiology::StatusCode status_code,
                              int64_t frame_timestamp);
 

    absl::StatusOr<double> GetTunedExposure() const;

    absl::StatusOr<double> GetTunedGain() const;

    absl::StatusOr<double> GetTunedWhiteBalance() const;

    cv::Mat ProcessFrameForDisplay(const cv::Mat& frame) const;
 
private:
    CameraTunerSettings settings_;

    std::shared_ptr<VideoSource> video_source_;

    TuningStage stage_;
 
    // White balance state
    bool supports_white_balance_;
    int wb_frame_counter_;
    double locked_white_balance_;
 
    // Exposure reduction state
    double current_exposure_;
    int exposure_iteration_count_;
    int64_t last_frame_timestamp_;
    double current_framerate_;
    int exposure_settle_frame_count_;
 
    // Gain increase state
    double current_gain_;
    int gain_iteration_count_;
    int gain_settle_frame_count_;

    absl::Status ProcessAutoWhiteBalanceStage();

    absl::Status ProcessExposureSearchStage(presage::physiology::StatusCode status_code,
                                             int64_t frame_timestamp);

    absl::Status ProcessGainSearchStage(presage::physiology::StatusCode status_code);

    absl::Status ValidateVideoSourceControls();
};
 
} // namespace presage::smartspectra::video_source