#include "../../../shared_cpp/OrthographicRenderer.h"
#include "../../../shared_cpp/types.h"
#include "../../../shared_cpp/WebglContext.h"
#include "../../../shared_cpp/mathlib.h"
#include "../../../shared_cpp/MainLoop.h"
#include <cstdio>
#include <cmath>
#include <emscripten/html5.h>
#include <unistd.h>
#include <pthread.h>
#include <cmath>
#include <cfloat>

struct Rigidbody {
	Vector2 linearForce = { 0, 0 };
    Vector2 velocity = { 0, 0 };
    Vector2 position = { 0, 0 };
    float32 mass = 1.f;

	float32 torque = 0.f;
	float32 rotationalVelocity = 0.f;
	float32 rotation = 0.f;
	float32 momentOfInertia = 1.f;

    void reset() {
        linearForce = { 0, 0 };
        velocity = { 0, 0 };
		rotationalVelocity = 0.f;
		rotation = 0.f;
    }

    void applyForce(Vector2 force, Vector2 pointOfApplication) {
        linearForce += force;
	    torque += pointOfApplication.getPerp().dot(force);
    }

    void applyGravity() {
		applyForce(Vector2 { 0.f, -100.f }, Vector2 { 0.f, 0.f });
    }

    void update(float32 deltaTimeSeconds) {
        applyGravity();
        
        Vector2 acceleration = linearForce / mass;
        velocity += (acceleration * deltaTimeSeconds);
        position += (velocity * deltaTimeSeconds);
        linearForce = Vector2 { 0.f, 0.f };

		// New: Update the rotational velocity as well
		float32 rotationalAcceleration = torque / momentOfInertia;
		rotationalVelocity += (rotationalAcceleration * deltaTimeSeconds);
		rotation += (rotationalVelocity * deltaTimeSeconds);
		torque = 0.f;
    }
};

struct Rectangle {
	OrthographicShape shape;
    Rigidbody body;
	Vector2 originalPoints[4];
	Vector2 transformedPoints[4];

	void load(OrthographicRenderer* renderer, Vector4 color, float32 width, float32 height) {
        color = color.toNormalizedColor();

		float32 halfWidth = width / 2.f;
		float32 halfHeight = height / 2.f;

	    OrthographicVertex vertices[6];
		vertices[0].position = Vector2 { -halfWidth, -halfHeight };
		vertices[1].position = Vector2 { -halfWidth, halfHeight };
		vertices[2].position = Vector2 { halfWidth, halfHeight };
		vertices[3].position = Vector2 { -halfWidth, -halfHeight };
		vertices[4].position = Vector2 { halfWidth, -halfHeight };
		vertices[5].position = Vector2 { halfWidth, halfHeight };
		
		for (int32 i = 0; i < 6; i++) {
			vertices[i].color = color;
		}

		originalPoints[0] = vertices[0].position;
		originalPoints[1] = vertices[1].position;
		originalPoints[2] = vertices[2].position;
		originalPoints[3] = vertices[4].position;
		
		shape.load(vertices, 6, renderer);
		body.reset();

		body.momentOfInertia = (width * width + height * height) * (body.mass / 12.f);
	}

	void update(float32 dtSeconds) {
		body.update(dtSeconds);
		shape.model = Mat4x4().translateByVec2(body.position).rotate2D(body.rotation);

		// Note: This helps us check if the cursor is within the bounds of the
		// rectangle later on.
		for (int idx = 0; idx < 4; idx++) {
			transformedPoints[idx] = shape.model * originalPoints[idx];
		}
	}

	void render(OrthographicRenderer* renderer) {
		shape.render(renderer);
	}

	void unload() {
		shape.unload();
	}
};


EM_BOOL onPlayClicked(int eventType, const EmscriptenMouseEvent* mouseEvent, void* userData);
EM_BOOL onStopClicked(int eventType, const EmscriptenMouseEvent* mouseEvent, void* userData);

void load();
void update(float32 time, void* userData);
void unload();

WebglContext context;
OrthographicRenderer renderer;
MainLoop mainLoop;
Rectangle r1;
Rectangle r2;

int main() {
	context.init("#gl_canvas");
    emscripten_set_click_callback("#gl_canvas_play", NULL, false, onPlayClicked);
    emscripten_set_click_callback("#gl_canvas_stop", NULL, false, onStopClicked);
    return 0;
}

void load() {
    renderer.load(&context);

    r1.load(&renderer, Vector4 { 55.f, 235.f, 35.f, 255.f }, 128.f, 64.f);
	r1.body.mass = 3.f;
    r1.body.position = Vector2 { context.width / 4.f, context.height / 4.f };
	r1.body.velocity = Vector2 { 100.f, 250.f };

	r2.load(&renderer, Vector4 { 235.f, 5.f, 35.f, 255.f }, 96.f, 64.f);
	r2.body.mass = 1.f;
    r2.body.position = Vector2 { context.width * (3.f / 4.f), context.height * (3.f / 4.f) };
	r2.body.velocity = Vector2 { -300.f, -150.f };

    mainLoop.run(update);
}

void handleCollisionWithWall(Rectangle* r) {
	if (r->body.position.x <= 0.f) {
        r->body.position.x = 0.f;
        r->body.velocity = r->body.velocity - Vector2 { 1.f, 0.f } * (2 * (r->body.velocity.dot(Vector2 { 1.f, 0.f })));
    }
    if (r->body.position.y <= 0.f) {
        r->body.position.y = 0.f;
        r->body.velocity = r->body.velocity - Vector2 { 0.f, 1.f } * (2 * (r->body.velocity.dot(Vector2 { 0.f, 1.f })));
    } 
    if (r->body.position.x >= 800.f) {
        r->body.position.x = 800.f;
        r->body.velocity = r->body.velocity - Vector2 { -1.f, 0.f } * (2 * (r->body.velocity.dot(Vector2{ -1.f, 0.f })));
    }
    if (r->body.position.y >= 600.f) {
        r->body.position.y = 600.f;
        r->body.velocity = r->body.velocity - Vector2 { 0.f, -1.f } * (2 * (r->body.velocity.dot(Vector2 { 0.f, -1.f }))) ;
    }
}

void update(float32 deltaTimeSeconds, void* userData) {
    r1.update(deltaTimeSeconds);
	r2.update(deltaTimeSeconds);

	handleCollisionWithWall(&r1);
	handleCollisionWithWall(&r2);

	
	// Renderer
	renderer.render();
    r1.render(&renderer);
	r2.render(&renderer);
}

void unload() {
    mainLoop.stop();
    renderer.unload();
    r1.unload();
	r2.unload();
}

//
// Interactions with DOM handled below
//
EM_BOOL onPlayClicked(int eventType, const EmscriptenMouseEvent* mouseEvent, void* userData) {
    printf("Play clicked\n");
    
    load();
    return true;
}

EM_BOOL onStopClicked(int eventType, const EmscriptenMouseEvent* mouseEvent, void* userData) {
    printf("Stop clicked\n");
    unload();
    return true;
}