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

namespace Misaki.ShaderGUI
{
    public static class MaterialEditorHelpers
    {
        /// <summary>
        /// Gets all the materials from the material editor.
        /// </summary>
        /// <param name="editor">The material editor.</param>
        /// <returns>All the materials from the material editor.</returns>
        public static IEnumerable<Material> GetMaterials(this MaterialEditor editor)
        {
            foreach (var target in editor.targets)
            {
                if (target is Material material)
                {
                    yield return material;
                }
            }
        }

        /// <summary>
        /// Sets a keyword on all the materials in the material editor.
        /// </summary>
        /// <param name="editor">The material editor.</param>
        /// <param name="keywordName">The name of the keyword</param>
        /// <param name="value">The value of the keyword.</param>
        public static void SetKeyword(this MaterialEditor editor, string keywordName, bool value)
        {
            foreach (var material in editor.GetMaterials())
            {
                material.SetKeyword(new LocalKeyword(material.shader, keywordName), value);
            }
        }

        /// <summary>
        /// Applies a change to all the materials in the material editor.
        /// </summary>
        /// <param name="editor">The material editor.</param>
        /// <param name="predicate">The predicate to determine if the change should be applied to the material.</param>
        /// <param name="changeAction">The action to apply the change.</param>
        public static void ApplyChange(this MaterialEditor editor, Predicate<Material> predicate, Action changeAction)
        {
            foreach (var material in editor.GetMaterials())
            {
                if (!predicate(material))
                {
                    continue;
                }

                changeAction();
                editor.RegisterPropertyChangeUndo(material.name);
            }
        }

        /// <summary>
        /// Applies a change to all the materials in the material editor.
        /// </summary>
        /// <param name="editor">The material editor.</param>
        /// <param name="changeAction">The action to apply the change.</param>
        public static void ApplyChange(this MaterialEditor editor, Action<Material> changeAction)
        {
            foreach (var material in editor.GetMaterials())
            {
                changeAction(material);
                editor.RegisterPropertyChangeUndo(material.name);
            }
        }

        #region GUI

        /// <summary>
        /// Draws a single line texture property with a keyword toggle.
        /// </summary>
        /// <param name="editor">The material editor.</param>
        /// <param name="label">The label of the texture property.</param>
        /// <param name="textureProperty">The texture property to draw.</param>
        /// <returns>True if the texture property is not null. Otherwise, false.</returns>
        public static bool KeywordTexturePropertySingleLine(this MaterialEditor editor, GUIContent label, MaterialProperty textureProperty, string keywordName = null)
        {
            return KeywordTexturePropertySingleLine(editor, label, textureProperty, null, null, keywordName);
        }

        /// <summary>
        /// Draws a single line texture property with a keyword toggle.
        /// </summary>
        /// <param name="editor">The material editor. </param>
        /// <param name="label">The label of the texture property.</param>
        /// <param name="textureProperty">The texture property to draw.</param>
        /// <param name="extraProperty">The first extra property to draw.</param>
        /// <returns>True if the texture property is not null. Otherwise, false.</returns>
        public static bool KeywordTexturePropertySingleLine(this MaterialEditor editor, GUIContent label, MaterialProperty textureProperty, MaterialProperty extraProperty, string keywordName = null)
        {
            return KeywordTexturePropertySingleLine(editor, label, textureProperty, extraProperty, null, keywordName);
        }

        /// <summary>
        /// Draws a single line texture property with a keyword toggle.
        /// </summary>
        /// <param name="editor">The material editor. </param>
        /// <param name="label">The label of the texture property.</param>
        /// <param name="textureProperty">The texture property to draw.</param>
        /// <param name="extraProperty1">The first extra property to draw.</param>
        /// <param name="extraProperty2">The second extra property to draw.</param>
        /// <returns>True if the texture property is not null. Otherwise, false.</returns>
        public static bool KeywordTexturePropertySingleLine(this MaterialEditor editor, GUIContent label, MaterialProperty textureProperty, MaterialProperty extraProperty1, MaterialProperty extraProperty2, string keywordName = null)
        {
            EditorGUI.BeginChangeCheck();
            editor.TexturePropertySingleLine(label, textureProperty, extraProperty1, extraProperty2);
            if (EditorGUI.EndChangeCheck())
            {
                editor.SetKeyword(string.IsNullOrEmpty(keywordName) ? textureProperty.name.ToUpper() : keywordName, textureProperty.textureValue != null);
            }

            return textureProperty.textureValue != null;
        }

        #endregion
    }
}