#ifndef CAMERA_H
#define CAMERA_H

#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>

const float CAMERA_HEIGHT = 1.7f;
const float GRAVITY = 18.6f; // Should be in m/s^2 but it doesn't really work out with 9.8 so we double it

class Camera
{
  public:
    glm::vec3 position;
    glm::vec3 target;
    glm::vec3 direction;
    glm::vec3 up;

    // Movement
    glm::vec3 horizontal_velocity;
    glm::vec3 forward_velocity;
    glm::vec3 vertical_velocity;

    float speed;

    glm::vec3 worldUp;

    Camera(float speed, glm::vec3 pos)
    {
        this->speed = speed;
        this->vertical_velocity = glm::vec3(0.0f);

        this->horizontal_velocity = glm::vec3(0.0f);
        this->forward_velocity = glm::vec3(0.0f);

        this->position = pos;
        this->target = glm::vec3(0.0f, 0.0f, -1.0f);

        this->direction = glm::normalize(this->position);
        this->worldUp = glm::vec3(0.0f, 1.0f, 0.0f);

        glm::vec3 right = glm::normalize(glm::cross(up, this->direction));
        this->up = glm::cross(this->direction, right);
    }

    Camera(glm::vec3 pos, glm::vec3 target, float speed)
    {
        this->speed = speed;
        this->vertical_velocity = glm::vec3(0.0f);

        this->horizontal_velocity = glm::vec3(0.0f);
        this->forward_velocity = glm::vec3(0.0f);

        this->position = pos;
        this->target = target;

        this->direction = glm::normalize(this->position - this->target);
        this->worldUp = glm::vec3(0.0f, 1.0f, 0.0f);

        glm::vec3 right = glm::normalize(glm::cross(up, this->direction));
        this->up = glm::cross(this->direction, right);
    }

    glm::mat4 getView()
    {
        glm::mat4 v = glm::lookAt(this->position,
                           this->target + this->position,
                           this->worldUp);

        v = glm::translate(v, glm::vec3(0.0f, -CAMERA_HEIGHT, 0.0f));

        return v;
    }

    void move(float time) // time passed in seconds since last move
    {
        bool in_air = this->position.y > 0;

        if (this->position.y > 0)
            this->vertical_velocity.y -= (GRAVITY * time); // no way! physics reference?

        glm::vec3 velocity = this->forward_velocity + this->horizontal_velocity + this->vertical_velocity;

        glm::vec3 movement = (velocity * time);
        this->position += movement;

        // Don't want to clip into the ground right
        if (this->position.y <= 0 && in_air)
        {
            this->position.y = 0.0f;
            this->vertical_velocity.y = 0.0f;
        }

    }

};

#endif