#include "pgm_drawing_context.hpp"
#include <cmath>

PgmDrawingContext::PgmDrawingContext(const std::filesystem::path& path, size_t width, size_t height)
    : m_bitmap(width, height, Color{0xFF})
{
}

void PgmDrawingContext::DrawLine(const math::Vector& p0, const math::Vector& p1)
{
    RasterizeLine(static_cast<int>(p0.x), static_cast<int>(p0.y), static_cast<int>(p1.x), static_cast<int>(p1.y));
}

void PgmDrawingContext::DrawRectangle(const math::Vector& pos, const math::Vector& size, float angle)
{
    const float sina = std::sin(angle);
    const float cosa = std::cos(angle);

    const math::Vector bX{cosa, sina};
    const math::Vector bY{-sina, cosa};

    const auto& pD = pos;
    const auto pA = pD + bY * size.y;
    const auto pB = pA + bX * size.x;
    const auto pC = pD + bX * size.x;

    PgmDrawingContext::DrawLine(pA, pB);
    PgmDrawingContext::DrawLine(pB, pC);
    PgmDrawingContext::DrawLine(pC, pD);
    PgmDrawingContext::DrawLine(pD, pA);
}

void PgmDrawingContext::DrawCircle(const math::Vector& center, float radius)
{
}

void PgmDrawingContext::RasterizeLine(int x0, int y0, int x1, int y1)
{
    int dx = abs(x1 - x0), sx = x0 < x1 ? 1 : -1;
    int dy = -abs(y1 - y0), sy = y0 < y1 ? 1 : -1;
    int err = dx + dy, e2; /* error value e_xy */

    for (;;)
    { /* loop */
        m_bitmap[y0][x0].l = 0x00;
        if (x0 == x1 && y0 == y1)
            break;
        e2 = 2 * err;
        if (e2 >= dy)
        {
            err += dy;
            x0 += sx;
        } /* e_xy+e_x > 0 */
        if (e2 <= dx)
        {
            err += dx;
            y0 += sy;
        } /* e_xy+e_y < 0 */
    }
}