/// <summary>
/// MIT License - Copyright(c) 2019 Ugo Belfiore
/// </summary>

using UnityEngine;
using System;

namespace PerspectiveSwitcher
{
    /// <summary>
    /// this class containt the datas of the projection matrix
    /// </summary>
    [Serializable]
    public class MatrixBlendData
    {
        public enum MatrixType
        {
            PERSPECTIVE = 10,
            ORTHOGRAPHIC = 20
        }

        public MatrixType MatrixCurrentType = MatrixType.PERSPECTIVE;


        public float NearClippingPlane = .3f;
        public float FarClippingPlane = 1000f;
        public float FieldOfView = 60f;
        public float OrthographicSize = 5f;

        private Matrix4x4 _currentCalculatedMatrix;

        public MatrixBlendData(MatrixBlendData.MatrixType matrixType)
        {
            MatrixCurrentType = matrixType;
            Init();
        }

        /// <summary>
        /// construct the current matrix based on the class settings
        /// </summary>
        public void Init()
        {
            float aspectRatio = 16f / 9f;
            switch (MatrixCurrentType)
            {
                case MatrixType.ORTHOGRAPHIC:
                    _currentCalculatedMatrix = ExtMatrix.GetMatrixOrthographic(aspectRatio, OrthographicSize, NearClippingPlane, FarClippingPlane);
                    break;
                case MatrixType.PERSPECTIVE:
                    _currentCalculatedMatrix = ExtMatrix.GetMatrixPerspective(aspectRatio, FieldOfView, NearClippingPlane, FarClippingPlane);
                    break;
            }
        }

        /// <summary>
        /// reset the projection matrix of the camera
        /// </summary>
        /// <param name="camRef">main camera reference</param>
        public void ResetCameraToMatrix(Camera camRef)
        {
            switch (MatrixCurrentType)
            {
                case MatrixType.ORTHOGRAPHIC:
                    camRef.orthographic = true;
                    camRef.orthographicSize = OrthographicSize;
                    camRef.ResetProjectionMatrix();
                    break;
                case MatrixType.PERSPECTIVE:
                    camRef.orthographic = false;
                    camRef.fieldOfView = FieldOfView;
                    camRef.ResetProjectionMatrix();
                    break;
            }
        }

        /// <summary>
        /// get the final matrix corresponding to all the setting.
        /// You NEED to call Init() BEFORE calling this function
        /// </summary>
        /// <returns></returns>
        public Matrix4x4 GetSetuppedMatrix()
        {
            return (_currentCalculatedMatrix);
        }

        /// <summary>
        /// From a previous and a next matrice, get a lerped one by an evaluated time
        /// </summary>
        /// <param name="timeEvaluated">time of the lerp</param>
        /// <param name="prevMatrix">start lerp matrix</param>
        /// <param name="nextMatrix">end lerp matrix</param>
        /// <param name="curve">curve if we want to add an ease to the lerp</param>
        /// <returns>return the current lerped matrix</returns>
        public static Matrix4x4 DoMatrixTransition(float timeEvaluated, Matrix4x4 prevMatrix, Matrix4x4 nextMatrix)
        {
            return (ExtMatrix.MatrixLerp(prevMatrix, nextMatrix, timeEvaluated));
        }
    }
}