#pragma once

#include <cmath>
#include <glm/vec2.hpp>
#include <glm/vec4.hpp>

struct UVRegion {
    float u1;
    float v1;
    float u2;
    float v2;

    UVRegion(float u1, float v1, float u2, float v2)
        : u1(u1), v1(v1), u2(u2), v2(v2) {
    }

    UVRegion() : u1(0.0f), v1(0.0f), u2(1.0f), v2(1.0f) {
    }

    inline float getWidth() const {
        return fabs(u2 - u1);
    }

    inline float getHeight() const {
        return fabs(v2 - v1);
    }

    void autoSub(float w, float h, float x, float y) {
        x *= 1.0f - w;
        y *= 1.0f - h;
        float uvw = getWidth();
        float uvh = getHeight();
        u1 = u1 + uvw * x;
        v1 = v1 + uvh * y;
        u2 = u1 + uvw * w;
        v2 = v1 + uvh * h;
    }

    inline glm::vec2 apply(const glm::vec2& uv) {
        float w = getWidth();
        float h = getHeight();
        return glm::vec2(u1 + uv.x * w, v1 + uv.y * h);
    }

    void scale(float x, float y) {
        float w = u2 - u1;
        float h = v2 - v1;
        float cx = (u1 + u2) * 0.5f;
        float cy = (v1 + v2) * 0.5f;
        u1 = cx - w * 0.5f * x;
        v1 = cy - h * 0.5f * y;
        u2 = cx + w * 0.5f * x;
        v2 = cy + h * 0.5f * y;
    }

    void scale(const glm::vec2& vec) {
        scale(vec.x, vec.y);
    }

    void set(const glm::vec4& vec) {
        u1 = vec.x;
        v1 = vec.y;
        u2 = vec.z;
        v2 = vec.w;
    }

    UVRegion operator*(const glm::vec2& scale) const {
        auto copy = UVRegion(*this);
        copy.scale(scale);
        return copy;
    }
};