#pragma once

#include "fgc/ExposurePolicy.h"

#include <map>
#include <optional>
#include <string>

namespace fgc {

// Per-angle exposure memory: what settings worked last time the gimbal looked
// this way. This is what lets a triggered capture start from a setting known to
// be roughly right, instead of paying the camera's own auto-exposure several
// frames to re-converge at every waypoint.
//
// Keyed by QUANTISED yaw/pitch rather than waypoint index, so the memory survives
// an edit to the scan grid and also serves ControlCode 1 directed moves, which
// have no waypoint index at all.

struct StoreEntry {
    double    yaw_deg      = 0.0;
    double    pitch_deg    = 0.0;
    double    exposure_us  = 0.0;
    double    gain_db      = 0.0;
    double    sharpness    = 0.0;   // sharpness of the last accepted frame here
    double    mean_luma    = 0.0;
    long long timestamp_ms = 0;     // when this entry was last updated (epoch ms)
    int       attempts     = 0;     // attempts the last visit needed
};

class ExposureStore {
public:
    // quantum_deg: angle bucket size. stale_s: how old an entry may be and still
    // be trusted as this angle's seed.
    explicit ExposureStore(std::string path, double quantum_deg = 1.0, long long stale_s = 1800);

    // Load from / save to the CSV. Both are tolerant: a missing file is simply an
    // empty store, and a malformed row is skipped rather than failing the load, so
    // a corrupt line can never stop a scan from running.
    bool load();
    bool save() const;

    // Bucket key for an angle, e.g. "y137_p-5".
    static std::string keyFor(double yaw_deg, double pitch_deg, double quantum_deg);

    std::optional<StoreEntry> find(double yaw_deg, double pitch_deg) const;
    std::size_t               size() const { return entries_.size(); }
    const std::string&        path() const { return path_; }

    // Three-tier seed, in order of how well each predicts the CURRENT light:
    //   1. this angle's own entry, if fresher than stale_s;
    //   2. else the last settings accepted anywhere - light changes affect all
    //      angles together, so a 30 s old reading one heading over beats an
    //      hour-old reading at this exact heading;
    //   3. else the configured defaults.
    CaptureSettings seed(double yaw_deg, double pitch_deg, long long now_ms,
                         const CaptureSettings& defaults) const;

    // This angle's reference sharpness for the relative blur check, or 0 when
    // unknown or too old to compare against.
    double referenceSharpness(double yaw_deg, double pitch_deg, long long now_ms) const;

    // Record an accepted capture.
    void update(double yaw_deg, double pitch_deg, const CaptureSettings& settings,
                const ImageMetrics& metrics, long long now_ms, int attempts);

private:
    bool fresh(const StoreEntry& e, long long now_ms) const;

    std::string                       path_;
    double                            quantum_deg_;
    long long                         stale_s_;
    std::map<std::string, StoreEntry> entries_;
    std::optional<CaptureSettings>    last_accepted_;
    long long                         last_accepted_ms_ = 0;
};

}  // namespace fgc