#pragma once

#include <FastLED.h>
#include "fl/stl/fixed_point/s16x16.h"  // from FastLED (was fl/fixed_point/s16x16.h in older versions)

using coord = fl::s16x16;

// convert integer pixel coordinates to buffer index (row-major, y down)
static inline int pixelIndex(int x, int y) {
    if (kMatrixSerpentine && (y & 1)) {
        // odd rows are reversed
        return y * kMatrixWidth + (kMatrixWidth - 1 - x);
    } else {
        return y * kMatrixWidth + x;
    }
}

// map fixed-point coordinate to integer pixel by truncation
static inline bool coordToPixel(coord x, coord y, int &outX, int &outY) {
    // convert to integer, rounding toward zero (same as >> FRAC_BITS)
    outX = x.to_int();
    outY = y.to_int();
    // unsigned cast: combines < 0 and >= width into a single comparison per axis
    if ((unsigned)outX >= kMatrixWidth || (unsigned)outY >= kMatrixHeight) {
        return false;
    }
    return true;
}

// Write a pixel's color using integer coords (overwrites existing value).
// Avoids fixed-point round-trip in hot loops where coordinates are already integers.
static inline bool setPixelXY(int x, int y, const CRGB &color) {
    if ((unsigned)x >= kMatrixWidth || (unsigned)y >= kMatrixHeight) {
        return false;
    }
    leds[pixelIndex(x, y)] = color;
    return true;
}

// Additively composite a color onto a pixel using integer coords (dst += src).
// Used by AA drawing routines where multiple primitives or sub-pixel contributions
// accumulate on a freshly-cleared frame buffer.
static inline bool addPixelXY(int x, int y, const CRGB &color) {
    if ((unsigned)x >= kMatrixWidth || (unsigned)y >= kMatrixHeight) {
        return false;
    }
    leds[pixelIndex(x, y)] += color;
    return true;
}

// Write a pixel's color using fixed-point coords (overwrites existing value).
static inline bool setPixel(coord x, coord y, const CRGB &color) {
    int ix = x.to_int(), iy = y.to_int();
    if ((unsigned)ix >= kMatrixWidth || (unsigned)iy >= kMatrixHeight) {
        return false;
    }
    leds[pixelIndex(ix, iy)] = color;
    return true;
}

// Additively composite a color onto a pixel using fixed-point coords (dst += src).
static inline bool addPixel(coord x, coord y, const CRGB &color) {
    int ix = x.to_int(), iy = y.to_int();
    if ((unsigned)ix >= kMatrixWidth || (unsigned)iy >= kMatrixHeight) {
        return false;
    }
    leds[pixelIndex(ix, iy)] += color;
    return true;
}