#pragma once

#include <JuceHeader.h>
#include "Params.h"

namespace serum
{

// ===========================================================================
// A single wavetable: 256 frames of 2048 samples each. Frames morph smoothly
// from a simple base shape to a complex one. Lookups interpolate bilinearly
// (across frames and within a frame). Tables are RAM-resident and generated
// lazily by the WavetableLibrary.
// ===========================================================================
class Wavetable
{
public:
    static constexpr int kFrames    = 256;
    static constexpr int kTableSize = 2048;

    Wavetable() = default;

    juce::String name;
    std::vector<std::vector<float>> frames;   // [frame][sample]

    bool isValid() const noexcept { return (int) frames.size() == kFrames; }

    void clear();

    // Build a table from a per-frame harmonic amplitude function.
    //   ampFn(frameIndex, harmonicNumber) -> amplitude  (harmonic 1 = fundamental)
    using HarmonicAmpFn = std::function<float (int, int)>;
    void buildHarmonic (const juce::String& name, HarmonicAmpFn ampFn, int numHarmonics = 64);

    // Read the table at a fractional frame position and a phase in [0,1).
    float read (float framePos, float phase) const noexcept;

    // Read with phase wrapped and clamped frame position.
    float readSafe (float framePos, float phase) const noexcept
    {
        phase -= std::floor (phase);
        return read (juce::jlimit (0.0f, (float) kFrames - 1.001f, framePos), phase);
    }

    // Copy raw samples of a frame into a destination buffer (for the GUI).
    void copyFrame (int frameIndex, float* dest, int numSamples) const;

private:
    static float lerp (float a, float b, float t) noexcept { return a + (b - a) * t; }
};

// ===========================================================================
// Lazily-built library of factory wavetables. Indices map to kWavetableNames.
// ===========================================================================
class WavetableLibrary
{
public:
    const Wavetable& getTable (int index) const;
    int size() const noexcept { return kNumWavetables; }

    // Force generation of all tables (used at prepare time).
    void prebuild();

private:
    mutable std::array<Wavetable, kNumWavetables> tables;
    mutable std::array<bool, kNumWavetables>      built { { false } };

    void buildTable (int index) const;
    static Wavetable makeBasic();
    static Wavetable makeSawPwm();
    static Wavetable makeSquareSync();
    static Wavetable makeTriangleFold();
    static Wavetable makeVowel();
    static Wavetable makeOrgan();
    static Wavetable makeWarmSaw();
    static Wavetable makeDigital();
    static Wavetable makeGlass();
    static Wavetable makeBass();
};

} // namespace serum