#pragma once

#include <stdint.h>

#include "../datatypes.cpp"
#include "../helpers.cpp"
#include "../buffer.cpp"
#include "../shaders/shaders.h"

namespace UwU {
  // line
  class Line {
    private:
      // plot lines if m <= 1
      template <class ShaderT>
      void lineLow(int16_t ix0, int16_t iy0, int16_t ix1, int16_t iy1, Buffer buffer, ShaderBase<ShaderT>& shader) {
        int16_t dx = ix1 - ix0;
        int16_t dy = iy1 - iy0;
        int16_t yi = 1;
        if (dy < 0) {
          yi = -1;
          dy = -dy;
        }
        int16_t d = (2 * dy) - dx;
        int16_t y = iy0;

        for (int16_t x = ix0; x < ix1; x++) {
          buffer.drawPixel((uint16_t)x, (uint16_t)y, shader.shade(x, y));
          if (d > 0) {
            y += yi;
            d += (2 * (dy - dx));
          } else {
            d += (2 * dy);
          }
        }
        return;
      }

      // plot lines if m >1
      template <class ShaderT>
      void lineHigh(int16_t ix0, int16_t iy0, int16_t ix1, int16_t iy1, Buffer buffer, ShaderBase<ShaderT>& shader) {
        int16_t dx = ix1 - ix0;
        int16_t dy = iy1 - iy0;
        int16_t xi = 1;
        if (dx < 0) {
          xi = -1;
          dx = -dx;
        }
        int16_t d = (2 * dx) - dy;
        int16_t x = ix0;

        for (int16_t y = iy0; y < iy1; y++) {
        buffer.drawPixel((uint16_t)x, (uint16_t)y, shader.shade(x, y));
        if (d > 0) {
          x += xi;
          d += (2 * (dx - dy));
        } else {
          d += (2 * dx);
        }
      }
      return;
      }

    public:
      Line(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1) {
        this->x0 = x0;
        this->y0 = y0;
        this->x1 = x1;
        this->y1 = y1;
      }
      Line() {}
      uint16_t x0;
      uint16_t y0;
      uint16_t x1;
      uint16_t y1;

      // Uses Bresenham's line algorithm to draw line of any slope
      template <class ShaderT>
      void draw (Buffer buffer, ShaderBase<ShaderT>& shader) {
        if (x0 > buffer.width || y0 > buffer.height || x1 > buffer.width || y1 > buffer.height) {return;};
        int16_t ix0 = x0;
        int16_t iy0 = y0;
        int16_t ix1 = x1;
        int16_t iy1 = y1;
        if (abs(iy1 - iy0) < abs(ix1 - ix0)) {
          if (ix0 > ix1) {
            lineLow(ix1, iy1, ix0, iy0, buffer, shader);
          } else {
            lineLow(ix0, iy0, ix1, iy1, buffer, shader);
          }
        } else {
          if (iy0 > iy1) {
            lineHigh(ix1, iy1, ix0, iy0, buffer, shader);
          } else {
            lineHigh(ix0, iy0, ix1, iy1, buffer, shader);
          }
        }
        return;
      }
  };
}