#pragma once
#include "DSPConstants.h"
#include <array>
#include <atomic>
#include <vector> // <- 1 row added

namespace FDNReverb {

     // -----------------------------------------------------------------------------
     // AcousticMetrics class
     // -----------------------------------------------------------------------------
     // Computes real-time acoustic metrics (D50, C50, C80, EDT).
    //  
     // Principle:
     // Accumulate the squared energy of the input signal in a ring buffer,
     // then compare it against the energy from 50 ms / 80 ms ago,
     // and compute the D50 / C50 / C80 values.
    //
     // Sample-rate support:
     // times (ms) are converted to sample counts,
     // so 44.1 kHz through 192 kHz are supported automatically.
    //
     // CPU:
     // O(1) per-sample computation (energy accumulation)
     // CPU overhead: below ~0.5%
     // -----------------------------------------------------------------------------
    class AcousticMetrics {
    public:
        AcousticMetrics() = default;

         // -- initialize --
         // sampleRate: sample rate (Hz)
         // analysisWindowMs: analysis window (ms). 2000 ms (2 s)
        void prepare(double sampleRate, float analysisWindowMs = 2000.0f);

         // -- per-sample state update --
         // sample: current Wet signal sample (mono)
        void processSample(float sample) noexcept;

         // -- value getters --
         // ranges:
         // D50: 0.0 ~ 1.0 ( 0.3~0.9)
        //   C50: -10 ~ +30 dB
        //   C80: -10 ~ +30 dB
         // EDT: 0.0 ~ 5.0 (s)
        float getD50() const noexcept { return d50.load(std::memory_order_relaxed); }
        float getC50() const noexcept { return c50.load(std::memory_order_relaxed); }
        float getC80() const noexcept { return c80.load(std::memory_order_relaxed); }
        float getEDT() const noexcept { return edt.load(std::memory_order_relaxed); }

         // --- added: expose energy history for drawing ---
         // get the instantaneous energy (squared) at a time offset in the past
        float getEnergyAtTimeOffset(float secondsAgo) const noexcept;

         // input activity detection (energy over the last 50 ms)
        bool isActive() const noexcept;

         // -- reset --
        void reset() noexcept;

    private:
         // -- compute --
        void updateMetrics() noexcept;

         // -- parameter --
        double sampleRate{ 48000.0 };
        float analysisWindowMs{ 2000.0f };

         // 50ms / 80ms sample count ( sample rate depends on )
        int samples50ms{ 2400 };   // @ 48kHz
        int samples80ms{ 3840 };   // @ 48kHz
        int analysisWindowSamples{ 96000 };  // 2000ms @ 48kHz

         // -- buffer --
         // energy history ( squared value )
        std::vector<float> energyHistory;
        int historyWritePos{ 0 };

         // -- cumulative energy value --
         // 50ms cumulative energy ( time )
        double recent50msEnergy{ 0.0 };
         // 80ms cumulative energy ( time )
        double recent80msEnergy{ 0.0 };
         // entire cumulative energy
        double totalEnergy{ 0.0 };

         // EDT : energy decay tracking
        float energyPeak{ 0.0f };
        int energyPeakPos{ 0 };

         // -- output value (atomic for thread safety) --
        std::atomic<float> d50{ 0.0f };
        std::atomic<float> c50{ 0.0f };
        std::atomic<float> c80{ 0.0f };
        std::atomic<float> edt{ 0.0f };

         // -- update --
         // sample compute ,
         // sample interval update
        int updateCounter{ 0 };
         static constexpr int kUpdateInterval = 1024; // about 21ms @ 48kHz
    };

}  // namespace FDNReverb