using UnityEngine;

public class ShipControls : MonoBehaviour {
    public Camera aim;
    public Timing timing;

    Rigidbody rigidBody;

    Vector3 initialPosition;
    Vector3 initialForce;
    Quaternion initialAim;

    Vector3 thrust;
    Vector3 strafe;

    float   strafeMag;
    float   thrustMag;
    float   stabliseMag;
    ForceMode forceMode;

    // Camera Controls
    float mouseSenseY = 1.0f;
    float mouseSenseX = 1.0f;
    float camPitch;
    float camYaw;

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

        // just stop the body from being affected by rotation for now
        // until the 3p camera is in to explain why
        rigidBody.freezeRotation = true;

        initialPosition = rigidBody.transform.position;
        initialAim = aim.transform.rotation;
        initialForce = Vector3.forward;

        thrust = Vector3.zero;
        strafe = Vector3.zero;

        thrustMag = 50.0f;
        strafeMag = 25.0f;
        stabliseMag = 75.0f;

        camPitch = initialAim.eulerAngles.x;
        camYaw = initialAim.eulerAngles.y;
        forceMode = ForceMode.Acceleration;
    }

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

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

    void FixedUpdate() {

        // when you hit the trigger...
        // GO
        // needs to be done here in fixedUpdate because otherwise the input is checked on every frame
        // so they will have already hit the button before this tick
        bool shouldStartTimer = !timing.timerEnabled && (thrust != Vector3.zero || strafe != Vector3.zero);
        if (shouldStartTimer)
            timing.StartTimer();

        // the ship being propelled forward
        rigidBody.AddForce(thrust, forceMode);

        // moving side to side
        rigidBody.AddRelativeForce(strafe, forceMode);

        // rotating towards the camera's orientation
        // not being done by a force because of strange behaviour
        // needs investigation
        float step = stabliseMag * Time.fixedDeltaTime;
        rigidBody.rotation = Quaternion.RotateTowards(transform.rotation, aim.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 aim.transform.TransformDirection(Vector3.forward) * 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 rigidBody.velocity.normalized * -1f * 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 += strafeMag * Vector3.up;
        if (Input.GetKey(KeyCode.S))
            strafe += strafeMag * Vector3.down;

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

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

        return strafe;
    }

    void processInput() {
        updateCamera();

        // don't just spam respawn
        if (Input.GetKeyDown(KeyCode.Space))
            Respawn();

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

    public void Respawn() {
        // IMPORTANT
        // stop the timer before we move the ship or anything
        // otherwise it might generate a checkpoint time
        // for the final sector
        timing.StopTimer();

        thrust = new Vector3(0.0f, 0.0f, 0.0f);
        transform.position = initialPosition;
        rigidBody.transform.forward = initialForce;
        rigidBody.velocity = new Vector3(0f, 0f, 0f);
        rigidBody.angularVelocity = new Vector3(0f, 0f, 0f);
        aim.transform.rotation = initialAim;

        camPitch = initialAim.eulerAngles.x;
        camYaw = initialAim.eulerAngles.y;

    }

    void updateCamera() {
        camPitch -= mouseSenseY * Input.GetAxis("Mouse Y");
        camYaw += mouseSenseX * Input.GetAxis("Mouse X");
        aim.transform.eulerAngles = new Vector3(camPitch, camYaw, 0.0f);
    }

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

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

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

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

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

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

    public float Speed() {
        return rigidBody.velocity.magnitude;
    }
}