using UnityEngine;

public class ShipControls : MonoBehaviour {
    public Camera m_camera;

    Rigidbody m_rigidBody;

    Vector3 m_initialPosition;
    Vector3 m_initialForce;
    Quaternion m_initialCamera;

    Vector3 m_thrust;
    Vector3 m_strafe;

    float   m_strafeMag;
    float   m_thrustMag;
    float   m_stabliseMag;
    ForceMode m_forceMode;

    // Camera Controls
    float m_mouseSenseY = 1.0f;
    float m_mouseSenseX = 1.0f;
    float m_camPitch;
    float m_camYaw;

    void Start() {
        // Cursor.lockState = CursorLockMode.Locked;
        m_rigidBody = GetComponent<Rigidbody>();

        m_initialPosition = m_rigidBody.transform.position;
        m_initialCamera = m_camera.transform.rotation;
        m_initialForce = Vector3.forward;

        m_thrust = Vector3.zero;
        m_strafe = Vector3.zero;

        m_thrustMag = 50.0f;
        m_strafeMag = 25.0f;
        m_stabliseMag = 75.0f;

        m_camPitch = m_initialCamera.eulerAngles.x;
        m_camYaw = m_initialCamera.eulerAngles.y;

        m_forceMode = ForceMode.Acceleration;
    }

    void Update() {
        // update the movement vectors every frame
        m_thrust = getThrust();
        m_strafe = getStrafe();

        // do everything else input related on every frame too
        processInput();
    }

    void FixedUpdate() {
        // the ship being propelled forward
        m_rigidBody.AddForce(m_thrust, m_forceMode);

        // moving side to side
        m_rigidBody.AddRelativeForce(m_strafe, m_forceMode);

        // rotating towards the camera's orientation
        // not being done by a force because of strange behaviour
        // needs investigation
        float step = m_stabliseMag * Time.fixedDeltaTime;
        m_rigidBody.rotation = Quaternion.RotateTowards(transform.rotation, m_camera.transform.rotation, step);
    }

    Vector3 getThrust() {
        // thrust in the direction of the camera
        if (Input.GetMouseButton(0))
            // transform from the camera's forward vector into world space
            return m_camera.transform.TransformDirection(Vector3.forward) * m_thrustMag;

        // brake just decelerates the ship against the direction it is moving
        if (Input.GetMouseButton(1)) {
            // the velocity is already in world space so we just invert it
            return m_rigidBody.velocity.normalized * -1f * m_thrustMag;
        }

        return Vector3.zero;
    }

    // 2D strafing
    // we combine all the vectors so you can move in 2 dimensions at once
    // thrust is added as a relative force so we don't need to convert to worldspace
    Vector3 getStrafe() {
        Vector3 strafe = new Vector3(0.0f, 0.0f, 0.0f);

        if (Input.GetKey(KeyCode.W))
            strafe += m_strafeMag * Vector3.up;
        if (Input.GetKey(KeyCode.S))
            strafe += m_strafeMag * Vector3.down;

        if (Input.GetKey(KeyCode.A))
            strafe += m_strafeMag * Vector3.left;

        if (Input.GetKey(KeyCode.D))
            strafe += m_strafeMag * Vector3.right;

        return strafe;
    }

    void processInput() {
        updateCamera();

        if (Input.GetKey(KeyCode.Space))
            Respawn();

        // if (Input.GetKey(KeyCode.Alpha1))
        //     m_forceMode = ForceMode.Acceleration;
        // if (Input.GetKey(KeyCode.Alpha2))
        //     m_forceMode = ForceMode.Impulse;
        // if (Input.GetKey(KeyCode.Alpha3))
        //     m_forceMode = ForceMode.Force;
        // if (Input.GetKey(KeyCode.Alpha4))
        //     m_forceMode = ForceMode.VelocityChange;

        if (Input.GetKey(KeyCode.F10))
            Application.Quit();
    }

    public void Respawn() {
        m_thrust = new Vector3(0.0f, 0.0f, 0.0f);
        transform.position = m_initialPosition;
        m_rigidBody.transform.forward = m_initialForce;
        m_rigidBody.velocity = new Vector3(0f, 0f, 0f);
        m_rigidBody.angularVelocity = new Vector3(0f, 0f, 0f);
        m_camera.transform.rotation = m_initialCamera;

        m_camPitch = m_initialCamera.eulerAngles.x;
        m_camYaw = m_initialCamera.eulerAngles.y;
    }

    void updateCamera() {
        m_camPitch -= m_mouseSenseY * Input.GetAxis("Mouse Y");
        m_camYaw += m_mouseSenseX * Input.GetAxis("Mouse X");
        m_camera.transform.eulerAngles = new Vector3(m_camPitch, m_camYaw, 0.0f);
    }

    void OnDrawGizmosSelected() {
        if (Application.isPlaying == false)
            return;

        Gizmos.color = Color.red;
        Vector3 right = m_camera.transform.TransformDirection(Vector3.right) * 10;
        Gizmos.DrawRay(transform.position, right);

        Gizmos.color = Color.green;
        Vector3 direction = m_camera.transform.TransformDirection(Vector3.up) * 10;
        Gizmos.DrawRay(transform.position, direction);

        Gizmos.color = Color.blue;
        Vector3 forward = m_camera.transform.TransformDirection(Vector3.forward) * 10;
        Gizmos.DrawRay(transform.position, forward);

        Gizmos.color = Color.yellow;
        Vector3 velocity = m_rigidBody.velocity;
        Gizmos.DrawRay(transform.position, velocity);

        Gizmos.color = Color.cyan;
        Vector3 thrust = m_thrust;
        Gizmos.DrawRay(transform.position, thrust);
    }
}