using System;

using Framework.Input.States;

using UnityEngine;

namespace Framework.Actors.Shooter {

  /// <summary>Lets the player control a character walking or running on the ground</summary>
  public class GroundMove : PlayerMove {

    /// <summary>Called when the actor has started the move</summary>
    public override void OnStarted() {
      base.OnStarted();

      EnableGravity(true);
    }

    /// <summary>Called once per physics frame</summary>
    /// <remarks>
    ///   Updates the world position of the actor
    /// </remarks>
    public override void FixedUpdate() {
      base.FixedUpdate();

      // Update the grounded state (the actor's physics component will have
      // moved it before or after this code ran, so the isGrounded state is now stale)
      bool isGrounded = RecheckGrounding();

      // If the actor is grounded, reset the jump count
      if(isGrounded) {
        ActorController.ConsecutiveJumpCount = 0;
      } else { // If the actor walks off a cliff, he'll be airborne
        SwitchToAirMove(jumped: false);
        ActorController.ActiveMove.FixedUpdate();
      }

      ShooterInputState inputState = InputManager.GetState<ShooterInputState>();

      // Standard left/right movement of the actor
      handleHorizontalMovement(inputState);

      // If the player pressed the jump key, we'll be airborne with upward velocity
      if(inputState.Jump.WasTriggered) {
        if(ActorController.ConsecutiveJumpCount < Abilities.JumpCount) {
          SwitchToAirMove(jumped: true);
          return;
        }
      }

    }

    /// <summary>
    ///   Switches the presenter to the animation state appropriate for this move
    /// </summary>
    protected override void SetPresenterState() {
      ShooterActorPresenter presenter = ActorPresenter;
      if(presenter != null) {
        presenter.SetGroundedState();
      }
    }

    /// <summary>Returns the speed at which the actor should move</summary>
    /// <param name="inputState">Inputs the player has made this frame</param>
    /// <returns>The speed at which the actor should move</returns>
    protected virtual float GetMovementSpeed(ShooterInputState inputState) {
      if(Abilities.CanSprint && inputState.Sprint.IsActive) {
        return Abilities.RunningSpeed;
      } else {
        return Abilities.WalkingSpeed;
      }
    }

    /// <summary>Movement logic to move the actor to the left and right</summary>
    /// <param name="inputState">Inputs the player has made this frame</param>
    private void handleHorizontalMovement(ShooterInputState inputState) {

      // Determine the speed at which the player wants to move and the highest
      // possible speed the actor could achieve (used to calculate acceleration)
      float fastestSpeed, runningSpeed, strafingSpeed;
      {
        fastestSpeed = GetMovementSpeed(inputState);
        runningSpeed = fastestSpeed * inputState.Running;
        strafingSpeed = Abilities.WalkingSpeed * inputState.Strafing;
      }

      float acceleration = fastestSpeed / Abilities.SecondsToFullSpeed;
      AccelerateToVelocity(runningSpeed, strafingSpeed, acceleration);

      // If the player is moving around, orient the actor towards the direction
      // the player is looking (it would look very silly if the player looked to
      // his left shoulder, pressed forward and ran sideways for longer distances).
      if((Math.Abs(runningSpeed) + Mathf.Abs(strafingSpeed)) > Abilities.WalkingSpeed * 0.1f) {
        ActorController.RotateOnlyBodyOnYTowards(
          ActorController.LookDirection, Abilities.TurnDegreesPerSecond * Time.fixedDeltaTime
        );
      }

    }

  }

} // namespace Framework.Actors.Shooter