#pragma once

#include <cstdint>
#include <memory>
#include <optional>

#include "track_core/model.hpp"
#include "track_core/pid_program.hpp"

namespace track_core {

struct TrackPidBandSnapshot {
    std::uint8_t band_id{};
    std::uint8_t heart_rate{};
    std::uint32_t heart_rate_sample_seq{};
    bool has_heart_rate{};
    bool hr_is_fresh{};
    std::uint16_t step_count{};
    bool has_step_count{};
    bool band_is_active{};
};

class PidHrRuntime {
public:
    using time_point = clock::time_point;

    PidHrRuntime();
    explicit PidHrRuntime(TrackPidConfig config);

    void set_pid_config(TrackPidConfig config);
    void update_target_hr_bpm(std::uint8_t target_hr_bpm);

    [[nodiscard]]
    expected<unit, TrackError> apply_pid_runtime_command(
        const TrackPidRuntimeCommand &command,
        const TrackConfig *track_config);

    [[nodiscard]]
    const TrackPidConfig &pid_config() const;

    void start(time_point now);
    void stop();
    void tick(const TrackConfig *track_config, const TrackPidBandSnapshot &band, time_point now);

    [[nodiscard]]
    TrackReport state_report(time_point now) const;

    [[nodiscard]]
    TrackInfo info() const;

    [[nodiscard]]
    TrackPidStatus pid_status(const TrackPidBandSnapshot &band, time_point now) const;

private:
    static constexpr std::uint8_t magic_pid_track_id = 0;

    [[nodiscard]]
    float effective_speed_m_s(float base_speed_m_s, const TrackConfig *track_config) const;

    TrackPidConfig config_{TrackPidConfig::default_config()};
    bool running_{false};
    Color color_{Color::white()};
    time_point start_timestamp_{};
    time_point last_tick_timestamp_{};
    std::optional<std::uint32_t> last_consumed_hr_sample_seq_;
    time_point last_consumed_hr_sample_time_{};
    float mileage_m_{0.0F};
    float base_speed_m_s_{0.0F};
    float effective_speed_m_s_{0.0F};
    std::unique_ptr<TrackPidProgramState> program_state_;
};

} // namespace track_core