#ifndef COLORSCALE_H
#define COLORSCALE_H

#include <initializer_list>
#include <vector>

class Color
{
public:
    Color();
    Color(int r, int g, int b);
    Color(int r, int g, int b, int a);
    Color(float r, float g, float b);
    Color(float r, float g, float b, float a);

    void getRgbF(float *r, float *g, float *b) const;
    void getRgbF(float *r, float *g, float *b, float *a) const;

    void setRgb(int r, int g, int b);
    void setRgb(int r, int g, int b, int a);

    void setRgbF(float r, float g, float b);
    void setRgbF(float r, float g, float b, float a);

    float r, g, b, a;
};

class ColorScale
{
public:
    ColorScale(const Color &firstColor, const Color &lastColor);
    ColorScale(std::initializer_list<Color> colors);
    ColorScale(const std::vector<Color> &colors);
    virtual ~ColorScale();

    Color operator ()(float t) const { return color(t); }
    virtual Color color(float t) const;

    void setExtents(float min, float max);
    float min() const { return m_min; }
    float max() const { return m_max; }
    int numColors() const { return m_colors.size(); }

    template<typename OutputIterator>
    void sample(std::size_t samples, OutputIterator it) const;

    static Color lerp(const Color &c1, const Color &c2, float _t);

protected:
    float m_min, m_max;
    std::vector<Color> m_colors;
};

template<typename OutputIterator>
void ColorScale::sample(std::size_t samples, OutputIterator it) const
{
    if (samples < 1) {
        return;
    }

    float step = (max() - min()) / samples;
    float r, g, b;
    for (float t = min(); samples-- > 0; t += step) {
        color(t).getRgbF(&r, &g, &b);
        *it++ = r;
        *it++ = g;
        *it++ = b;
    }
}

#endif // COLORSCALE_H