#pragma once

#include <cstdint>
#include <string>


struct Color {
    uint8_t r, g, b;
} __attribute__ ((packed));

typedef uint16_t Fixed;
constexpr int factor = 65536;
constexpr int shift = 16;


struct Gradient {
    Color at(Fixed x) const;

    static Gradient* make(int n) {
        Gradient *gradient = (Gradient*)malloc(
                sizeof(Gradient) + n * sizeof(*colors)
            );
        gradient->n_colors = n;
        return gradient;
    }

    unsigned int n_colors;
    Color colors[];
};

class Pattern {
public:
    virtual ~Pattern() {};

    struct State {};

    virtual State* start(int) const = 0;

    virtual void step(Color[], int, State*) const = 0;
};

class GradientPattern : public Pattern {
public:
    GradientPattern(
                Gradient *_gradient,
                int _cycle_length=20, int _cycle_time_ms=-1,
                bool _reverse=false, bool _march=false
            ) : cycle_length(_cycle_length),
                cycle_time_ms(  _cycle_time_ms < 0 ?
                                _cycle_length * 500 : _cycle_time_ms
                    ),
                reverse(_reverse), march(_march), gradient(_gradient)
            {}

    ~GradientPattern() { free(gradient); }

    State* start(int) const { return new State(); }

    void step(Color[], int, State*) const;

private:
    struct State : Pattern::State {
        State() : last_us(0), offset(0) {}
        int64_t last_us;
        Fixed offset;
    };

    int cycle_length;
    int cycle_time_ms;
    bool reverse;
    bool march;
    Gradient *gradient;
};

class LEDStrip {
public:
    LEDStrip(int length = 0);

    void step();

    virtual void show() = 0;
    virtual void length_changing(int) {};

    void setPattern(const Pattern *_pattern) { pattern = _pattern; update_state(); }
    const Pattern* getPattern() const { return pattern; }

    void setLength(int length);
    int getLength() const { return length; }

protected:
    int length;
    const Pattern *pattern;
    Color *pixels;

private:
    void update_state();

    Pattern::State *state;
};

class TerminalLEDs : public LEDStrip {
public:
    TerminalLEDs(int length = 0) : LEDStrip(length) {}
    void show();
};