#pragma once
#include <FastLED.h>

#include "Geometry.h"

/**
 * Generic interface for converting between virtual and physical coordinates
 */
struct CoordinateMapping {

    /**
     * Maps physical coordinates to virtual coordinates.
     * Virtual coordinates range from 0 to 255. Physical coordinates are
     * hardware-dependent.
     */
    virtual VirtualCoordinates physicalToVirtualCoords(const PhysicalCoordinates localCoords) const = 0;

    /**
     * Maps virtual coordinates to physical (aka, hardware) coordinates.
     * Virtual coordinates range from 0 to 255. Physical coordinates are
     * hardware-dependent.
     */
    virtual PhysicalCoordinates virtualToPhysicalCoords(const VirtualCoordinates virtualCoords) const = 0;

    /**
     * Returns the index of the underlying FastLED array, i.e., the physical
     * hardware pixel.
     */
    virtual int physicalCoordsToIndex(const PhysicalCoordinates localCoords) const = 0;
    virtual unsigned int physicalPixelCount() const = 0;
};

/**
 * Basic mapping for a contiguous 1-d linear display, eg, an LED strip.
 *
 * X value ranges from 0 to 255; all Y values are flattened to Y=0
 */
struct LinearCoordinateMapping: CoordinateMapping {
    unsigned int pixelCount = 1;
    unsigned int startPixel = 0;
    LinearCoordinateMapping() {}
    LinearCoordinateMapping(unsigned int count, unsigned int start) : pixelCount(count), startPixel(start) {}
    VirtualCoordinates physicalToVirtualCoords(const PhysicalCoordinates localCoords) const override {
        return VirtualCoordinates{map8(localCoords.x, 0, pixelCount), 0};
    }

    PhysicalCoordinates virtualToPhysicalCoords(const VirtualCoordinates virtualCoords) const override {
        return PhysicalCoordinates{scale8(pixelCount, virtualCoords.x), 0};
    }

    int physicalCoordsToIndex(const PhysicalCoordinates localCoords) const override {
        return localCoords.x + startPixel;
    }

    unsigned int physicalPixelCount() const override {
        return pixelCount;
    }
};

/**
 * The connection between the rendering engine and the physical hardware.
 * Provides direct access to the underlying FastLED array.
 */
class Display {
  public:

    Display(CRGB* pixels, int pixelCount, const CoordinateMapping* map)
      : m_pixels(pixels), m_pixelCount(pixelCount), m_coordMap(map) {}

    /**
     * Returns the physical pixel at the given physical coordinates
     */
    CRGB& pixelAt(const PhysicalCoordinates coords);

    /**
     * Returns the physical pixel at the given virtual coordinates
     */
    CRGB& pixelAt(const VirtualCoordinates coords);

    /**
     * Returns the physical pixel in the underlying FastLED array
     */
    CRGB& pixelAt(int idx);

    /**
     * Returns how many pixels are in this display
     */
    int pixelCount() const;

    /**
     * Returns the raw underlying FastLED array
     */
    CRGB* pixelBacking() const;
    const CoordinateMapping* coordinateMapping() const;

    /**
     * Sets every pixel to (0, 0, 0)
     */
    void clear();

    /**
     * Sets every pixel to the given display
     */
    void clear(const CRGB& color);

  private:
    CRGB* m_pixels;
    int m_pixelCount;
    const CoordinateMapping* m_coordMap;
};