using UnityEngine;
using System;
using UnityEditor;
using System.Collections.Generic;
using UnityEngine.Serialization;

namespace Unity.Cinemachine.Editor
{
    /// <summary>
    /// User-definable named presets for physical lenses.  This is a Singleton asset, available in editor only
    /// </summary>
    [Serializable]
    public sealed class CinemachinePhysicalLensPalette : ScriptableObject
    {
        static CinemachinePhysicalLensPalette s_Instance = null;
        static bool s_AlreadySearched = false;

        /// <summary>Get the singleton instance of this object, or null if it doesn't exist</summary>
        public static CinemachinePhysicalLensPalette InstanceIfExists
        {
            get
            {
                if (!s_AlreadySearched)
                {
                    s_AlreadySearched = true;
                    var guids = AssetDatabase.FindAssets("t:CinemachinePhysicalLensPalette");
                    for (int i = 0; i < guids.Length && s_Instance == null; ++i)
                        s_Instance = AssetDatabase.LoadAssetAtPath<CinemachinePhysicalLensPalette>(
                            AssetDatabase.GUIDToAssetPath(guids[i]));
                }
                return s_Instance;
            }
        }

        /// <summary>Get the singleton instance of this object.  Creates asset if nonexistent</summary>
        public static CinemachinePhysicalLensPalette Instance
        {
            get
            {
                if (InstanceIfExists == null)
                {
                    var newAssetPath = EditorUtility.SaveFilePanelInProject(
                            "Create Physical Lens Palette asset", "CinemachinePhysicalLensPalette", "asset",
                            "This editor-only file will contain the physical lens presets for this project");
                    if (!string.IsNullOrEmpty(newAssetPath))
                    {
                        s_Instance = CreateInstance<CinemachinePhysicalLensPalette>();

                        // Create some sample presets
                        var defaultPhysical = LensSettings.Default.PhysicalProperties;
                        s_Instance.Presets = new()
                        {
                            new () { Name = "21mm", FocalLength = 21f, PhysicalProperties = defaultPhysical },
                            new () { Name = "35mm", FocalLength = 35f, PhysicalProperties = defaultPhysical },
                            new () { Name = "58mm", FocalLength = 58f, PhysicalProperties = defaultPhysical },
                            new () { Name = "80mm", FocalLength = 80f, PhysicalProperties = defaultPhysical },
                            new () { Name = "125mm", FocalLength = 125f, PhysicalProperties = defaultPhysical }
                        };
                        AssetDatabase.CreateAsset(s_Instance, newAssetPath);
                        AssetDatabase.SaveAssets();
                        AssetDatabase.Refresh();
                    }
                }
                return s_Instance;
            }
        }

        /// <summary>Physical Lens Preset</summary>
        [Serializable]
        public struct Preset
        {
            /// <summary>The name of the preset</summary>
            [Tooltip("Lens Name")]
            [FormerlySerializedAs("m_Name")]
            public string Name;

            /// <summary>This is the camera focal length in mm</summary>
            [Tooltip("This is the camera focal length in mm")]
            [FormerlySerializedAs("m_FocalLength")]
            public float FocalLength;

            /// <summary>Physical lens settings</summary>
            [Tooltip("Physical lens settings")]
            public LensSettings.PhysicalSettings PhysicalProperties;
        }

        /// <summary>The array containing Preset definitions, for physical cameras</summary>
        [Tooltip("The array containing Preset definitions, for physical cameras")]
        public List<Preset> Presets = new();

        /// <summary>Get the index of the first physical preset that matches the preset name</summary>
        /// <param name="presetName">Name of the preset</param>
        /// <returns>the preset index, or -1 if no matching preset</returns>
        public int GetPresetIndex(string presetName)
            => Presets.FindIndex(x => x.Name == presetName);

        /// <summary>Get the index of the physical preset that matches the template</summary>
        /// <param name="p">Template holding the preset tsettings.  Name is ignored.</param>
        /// <returns>the preset index, or -1 if no matching preset</returns>
        public int GetMatchingPreset(Preset p)
        {
            return Presets.FindIndex(x => 
                Mathf.Approximately(x.FocalLength, p.FocalLength)
                && x.PhysicalProperties.GateFit == p.PhysicalProperties.GateFit
                && Mathf.Approximately(x.PhysicalProperties.LensShift.x, p.PhysicalProperties.LensShift.x)
                && Mathf.Approximately(x.PhysicalProperties.LensShift.y, p.PhysicalProperties.LensShift.y)
                && Mathf.Approximately(x.PhysicalProperties.SensorSize.x, p.PhysicalProperties.SensorSize.x)
                && Mathf.Approximately(x.PhysicalProperties.SensorSize.y, p.PhysicalProperties.SensorSize.y)
                && x.PhysicalProperties.Iso == p.PhysicalProperties.Iso
                && Mathf.Approximately(x.PhysicalProperties.ShutterSpeed, p.PhysicalProperties.ShutterSpeed)
                && Mathf.Approximately(x.PhysicalProperties.Aperture, p.PhysicalProperties.Aperture)
                &&x.PhysicalProperties.BladeCount == p.PhysicalProperties.BladeCount
                && Mathf.Approximately(x.PhysicalProperties.Curvature.x, p.PhysicalProperties.Curvature.x)
                && Mathf.Approximately(x.PhysicalProperties.Curvature.y, p.PhysicalProperties.Curvature.y)
                && Mathf.Approximately(x.PhysicalProperties.BarrelClipping, p.PhysicalProperties.BarrelClipping)
                && Mathf.Approximately(x.PhysicalProperties.Anamorphism, p.PhysicalProperties.Anamorphism));
        }
    }
}