#pragma once
#include <JuceHeader.h>

enum class BlepWave : int { Sine = 0, Saw, Square, Triangle };

class BlepOsc
{
public:
    void prepare (double sampleRate) { sr = sampleRate; resetPhase(); }
    void setWave (BlepWave w) { wave = w; }
    void setFrequency (float f) { freq = juce::jmax (0.0f, f); inc = freq / (float) sr; }
    void resetPhase (float p = 0.0f) { phase = juce::jlimit (0.0f, 1.0f, p); }

    inline float process()
    {
        // phase in [0..1)
        float out = 0.0f;
        float t = phase;
        phase += inc;
        if (phase >= 1.0f) phase -= 1.0f;

        switch (wave)
        {
            case BlepWave::Sine:    out = std::sin (2.0f * juce::MathConstants<float>::pi * t); break;

            case BlepWave::Saw:
            {
                // naive saw in [-1..1]
                float s = 2.0f * t - 1.0f;
                // apply BLEP at the discontinuity crossing t=0
                s -= polyBlep (t, inc);
                out = s;
            } break;

            case BlepWave::Square:
            {
                float s = (t < 0.5f ? 1.0f : -1.0f);
                // rising edge at 0.0, falling at 0.5
                s += polyBlep (t, inc) - polyBlep (std::fmod (t + 0.5f, 1.0f), inc);
                out = s;
            } break;

            case BlepWave::Triangle:
            {
                // integrate the BLEP square for band-limited tri
                float sq = (t < 0.5f ? 1.0f : -1.0f);
                sq += polyBlep (t, inc) - polyBlep (std::fmod (t + 0.5f, 1.0f), inc);
                // leaky integrator to keep DC under control
                z1 = z1 + (sq - z1) * inc;
                out = 2.0f * z1; // scale
            } break;
        }

        return out;
    }

private:
    // PolyBLEP as in Valimäki/Huovilainen
    static inline float polyBlep (float t, float dt)
    {
        // t in [0..1)
        if (t < dt)
        {
            t /= dt;
            return t + t - t * t - 1.0f;
        }
        else if (t > 1.0f - dt)
        {
            t = (t - 1.0f) / dt;
            return t * t + t + t + 1.0f;
        }
        return 0.0f;
    }

    double sr = 44100.0;
    float  freq = 440.0f, inc = 440.0f / 44100.0f;
    float  phase = 0.0f;
    float  z1 = 0.0f;
    BlepWave wave = BlepWave::Sine;
};