#include "InputSystem.h"

#include <GLFW/glfw3.h>

#include <iostream>

#include <glm/glm.hpp>

#include <glm/ext.hpp>

void InputSystem::ObserveKey(int key) {
	_keyCodeDictionaryObserver.emplace(key, KeyObserver(_window, key));
}

void InputSystem::Update() {
	for(auto& observer : _keyCodeDictionaryObserver) {
		observer.second.Update();
	}
}

void InputSystem::SetWindow(GLFWwindow* window) {
	_window = window;
}

bool InputSystem::IsLeftMouseDown() const
{
	return glfwGetMouseButton(_window, GLFW_MOUSE_BUTTON_LEFT) == GLFW_PRESS;
}

bool InputSystem::IsRightMouseDown() const
{
	return glfwGetMouseButton(_window, GLFW_MOUSE_BUTTON_RIGHT) == GLFW_PRESS;
}

void InputSystem::GetMousePos(glm::vec2& position) const
{
	double x, y;

	glfwGetCursorPos(_window, &x, &y);

	position.x = x;
	position.y = y;
}

void InputSystem::GetPickingRay(const glm::mat4& transform, glm::vec3& startingPoint, glm::vec3& direction) const {
	glm::vec2 screenSpacePosition;
	GetMousePos(screenSpacePosition);

	int screenWidth, screenHeight;
	glfwGetFramebufferSize(_window, &screenWidth, &screenHeight);

	glm::vec2 clipSpacePosition = glm::vec2(
		( screenSpacePosition.x / screenWidth ) * 2.0 - 1.0,
		1.0 - ( screenSpacePosition.y / screenHeight ) * 2.0
	);

	glm::vec4 nearPoint = glm::vec4(clipSpacePosition.x, clipSpacePosition.y, 0.01f, 1.0f);
	glm::vec4 farPoint = nearPoint;
	farPoint.z = 0.99f;

	glm::mat4 inverse = glm::inverse(transform);
	nearPoint = inverse * nearPoint;
	farPoint = inverse * farPoint;

	nearPoint /= nearPoint.w;
	farPoint /= farPoint.w;

	startingPoint = nearPoint;
	direction = farPoint - nearPoint;
}