using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using KinematicCharacterController;
using System;

namespace KinematicCharacterController.Walkthrough.FramePerfectRotation
{
    public struct PlayerCharacterInputs
    {
        public float MoveAxisForward;
        public float MoveAxisRight;
        public Quaternion CameraRotation;
    }

    public class MyCharacterController : MonoBehaviour, ICharacterController
    {
        public KinematicCharacterMotor Motor;

        [Header("Stable Movement")]
        public float MaxStableMoveSpeed = 10f;
        public float StableMovementSharpness = 15;
        public float OrientationSharpness = 10;

        [Header("Air Movement")]
        public float MaxAirMoveSpeed = 10f;
        public float AirAccelerationSpeed = 5f;
        public float Drag = 0.1f;

        [Header("Misc")]
        public Vector3 Gravity = new Vector3(0, -30f, 0);
        public Transform MeshRoot;
        public bool FramePerfectRotation = true;

        private Vector3 _moveInputVector;
        private Vector3 _lookInputVector;

        private void Start()
        {
            // Assign to motor
            Motor.CharacterController = this;
        }

        /// <summary>
        /// This is called every frame by MyPlayer in order to tell the character what its inputs are
        /// </summary>
        public void SetInputs(ref PlayerCharacterInputs inputs)
        {
            // Clamp input
            Vector3 moveInputVector = Vector3.ClampMagnitude(new Vector3(inputs.MoveAxisRight, 0f, inputs.MoveAxisForward), 1f);

            // Calculate camera direction and rotation on the character plane
            Vector3 cameraPlanarDirection = Vector3.ProjectOnPlane(inputs.CameraRotation * Vector3.forward, Motor.CharacterUp).normalized;
            if (cameraPlanarDirection.sqrMagnitude == 0f)
            {
                cameraPlanarDirection = Vector3.ProjectOnPlane(inputs.CameraRotation * Vector3.up, Motor.CharacterUp).normalized;
            }
            Quaternion cameraPlanarRotation = Quaternion.LookRotation(cameraPlanarDirection, Motor.CharacterUp);

            // Move and look inputs
            _moveInputVector = cameraPlanarRotation * moveInputVector;
            _lookInputVector = cameraPlanarDirection;
        }

        public void PostInputUpdate(float deltaTime, Vector3 cameraForward)
        {
            if (FramePerfectRotation)
            {
                _lookInputVector = Vector3.ProjectOnPlane(cameraForward, Motor.CharacterUp);

                Quaternion newRotation = default;
                HandleRotation(ref newRotation, deltaTime);
                MeshRoot.rotation = newRotation;
            }
        }

        private void HandleRotation(ref Quaternion rot, float deltaTime)
        {
            if (_lookInputVector != Vector3.zero)
            {
                rot = Quaternion.LookRotation(_lookInputVector, Motor.CharacterUp);
            }
        }

        /// <summary>
        /// (Called by KinematicCharacterMotor during its update cycle)
        /// This is called before the character begins its movement update
        /// </summary>
        public void BeforeCharacterUpdate(float deltaTime)
        {
        }

        /// <summary>
        /// (Called by KinematicCharacterMotor during its update cycle)
        /// This is where you tell your character what its rotation should be right now. 
        /// This is the ONLY place where you should set the character's rotation
        /// </summary>
        public void UpdateRotation(ref Quaternion currentRotation, float deltaTime)
        {
            HandleRotation(ref currentRotation, deltaTime);
        }

        /// <summary>
        /// (Called by KinematicCharacterMotor during its update cycle)
        /// This is where you tell your character what its velocity should be right now. 
        /// This is the ONLY place where you can set the character's velocity
        /// </summary>
        public void UpdateVelocity(ref Vector3 currentVelocity, float deltaTime)
        {
            Vector3 targetMovementVelocity = Vector3.zero;
            if (Motor.GroundingStatus.IsStableOnGround)
            {
                // Reorient velocity on slope
                currentVelocity = Motor.GetDirectionTangentToSurface(currentVelocity, Motor.GroundingStatus.GroundNormal) * currentVelocity.magnitude;

                // Calculate target velocity
                Vector3 inputRight = Vector3.Cross(_moveInputVector, Motor.CharacterUp);
                Vector3 reorientedInput = Vector3.Cross(Motor.GroundingStatus.GroundNormal, inputRight).normalized * _moveInputVector.magnitude;
                targetMovementVelocity = reorientedInput * MaxStableMoveSpeed;

                // Smooth movement Velocity
                currentVelocity = Vector3.Lerp(currentVelocity, targetMovementVelocity, 1 - Mathf.Exp(-StableMovementSharpness * deltaTime));
            }
            else
            {
                // Add move input
                if (_moveInputVector.sqrMagnitude > 0f)
                {
                    targetMovementVelocity = _moveInputVector * MaxAirMoveSpeed;

                    // Prevent climbing on un-stable slopes with air movement
                    if (Motor.GroundingStatus.FoundAnyGround)
                    {
                        Vector3 perpenticularObstructionNormal = Vector3.Cross(Vector3.Cross(Motor.CharacterUp, Motor.GroundingStatus.GroundNormal), Motor.CharacterUp).normalized;
                        targetMovementVelocity = Vector3.ProjectOnPlane(targetMovementVelocity, perpenticularObstructionNormal);
                    }

                    Vector3 velocityDiff = Vector3.ProjectOnPlane(targetMovementVelocity - currentVelocity, Gravity);
                    currentVelocity += velocityDiff * AirAccelerationSpeed * deltaTime;
                }

                // Gravity
                currentVelocity += Gravity * deltaTime;

                // Drag
                currentVelocity *= (1f / (1f + (Drag * deltaTime)));
            }
        }

        /// <summary>
        /// (Called by KinematicCharacterMotor during its update cycle)
        /// This is called after the character has finished its movement update
        /// </summary>
        public void AfterCharacterUpdate(float deltaTime)
        {
        }

        public bool IsColliderValidForCollisions(Collider coll)
        {
            return true;
        }

        public void OnGroundHit(Collider hitCollider, Vector3 hitNormal, Vector3 hitPoint, ref HitStabilityReport hitStabilityReport)
        {
        }

        public void OnMovementHit(Collider hitCollider, Vector3 hitNormal, Vector3 hitPoint, ref HitStabilityReport hitStabilityReport)
        {
        }

        public void PostGroundingUpdate(float deltaTime)
        {
        }

        public void AddVelocity(Vector3 velocity)
        {
        }

        public void ProcessHitStabilityReport(Collider hitCollider, Vector3 hitNormal, Vector3 hitPoint, Vector3 atCharacterPosition, Quaternion atCharacterRotation, ref HitStabilityReport hitStabilityReport)
        {
        }

        public void OnDiscreteCollisionDetected(Collider hitCollider)
        {
        }
    }
}