/* SPDX-License-Identifier: Apache-2.0
*
* The OpenSearch Contributors require contributions made to
* this file be licensed under the Apache-2.0 license or a
* compatible open source license.
*/
/*
* Modifications Copyright OpenSearch Contributors. See
* GitHub history for details.
*
*  Licensed to Elasticsearch B.V. under one or more contributor
*  license agreements. See the NOTICE file distributed with
*  this work for additional information regarding copyright
*  ownership. Elasticsearch B.V. licenses this file to you under
*  the Apache License, Version 2.0 (the "License"); you may
*  not use this file except in compliance with the License.
*  You may obtain a copy of the License at
*
* 	http://www.apache.org/licenses/LICENSE-2.0
*
*  Unless required by applicable law or agreed to in writing,
*  software distributed under the License is distributed on an
*  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
*  KIND, either express or implied.  See the License for the
*  specific language governing permissions and limitations
*  under the License.
*/

using System;
using System.Collections;
using System.Collections.Concurrent;
using System.Reflection;
using OpenSearch.Net;

namespace OpenSearch.Client
{
	public class PropertyWalker
	{
		private readonly int _maxRecursion;
		private readonly ConcurrentDictionary<Type, int> _seenTypes;
		private readonly Type _type;
		private readonly IPropertyVisitor _visitor;

		public PropertyWalker(Type type, IPropertyVisitor visitor, int maxRecursion = 0)
		{
			_type = GetUnderlyingType(type);
			_visitor = visitor ?? new NoopPropertyVisitor();
			_maxRecursion = maxRecursion;
			_seenTypes = new ConcurrentDictionary<Type, int>();
			_seenTypes.TryAdd(_type, 0);
		}

		private PropertyWalker(Type type, IPropertyVisitor visitor, int maxRecursion, ConcurrentDictionary<Type, int> seenTypes)
		{
			_type = type;
			_visitor = visitor;
			_maxRecursion = maxRecursion;
			_seenTypes = seenTypes;
		}

		public IProperties GetProperties(ConcurrentDictionary<Type, int> seenTypes = null, int maxRecursion = 0)
		{
			var properties = new Properties();

			if (seenTypes != null && seenTypes.TryGetValue(_type, out var seen) && seen > maxRecursion)
				return properties;

			foreach (var propertyInfo in _type.GetAllProperties())
			{
				var attribute = OpenSearchPropertyAttributeBase.From(propertyInfo);
				if (attribute != null && attribute.Ignore) continue;
				if (_visitor.SkipProperty(propertyInfo, attribute)) continue;

				var property = GetProperty(propertyInfo, attribute);
				if (property is IPropertyWithClrOrigin withCLrOrigin)
					withCLrOrigin.ClrOrigin = propertyInfo;
				properties.Add(propertyInfo, property);
			}

			return properties;
		}

		private IProperty GetProperty(PropertyInfo propertyInfo, OpenSearchPropertyAttributeBase attribute)
		{
			var property = _visitor.Visit(propertyInfo, attribute);
			if (property != null) return property;

			if (propertyInfo.GetMethod.IsStatic)
				return null;

			property = attribute ?? InferProperty(propertyInfo);

			if (property is IObjectProperty objectProperty)
			{
				var type = GetUnderlyingType(propertyInfo.PropertyType);
				var seenTypes = new ConcurrentDictionary<Type, int>(_seenTypes);
				seenTypes.AddOrUpdate(type, 0, (t, i) => ++i);
				var walker = new PropertyWalker(type, _visitor, _maxRecursion, seenTypes);
				objectProperty.Properties = walker.GetProperties(seenTypes, _maxRecursion);
			}

			_visitor.Visit(property, propertyInfo, attribute);

			return property;
		}

		private static IProperty InferProperty(PropertyInfo propertyInfo)
		{
			var type = GetUnderlyingType(propertyInfo.PropertyType);

			if (type == typeof(string))
				return new TextProperty
				{
					Fields = new Properties
					{
						{
							"keyword", new KeywordProperty
							{
								IgnoreAbove = 256
							}
						}
					}
				};

			if (type.IsEnum)
			{
				if (type.GetCustomAttribute<StringEnumAttribute>() != null
					|| propertyInfo.GetCustomAttribute<StringEnumAttribute>() != null)
					return new KeywordProperty();

				return new NumberProperty(NumberType.Integer);
			}

			if (type.IsValueType)
			{
				switch (type.Name)
				{
					case "Int32":
					case "UInt16":
						return new NumberProperty(NumberType.Integer);
					case "Int16":
					case "Byte":
						return new NumberProperty(NumberType.Short);
					case "SByte":
						return new NumberProperty(NumberType.Byte);
					case "Int64":
					case "UInt32":
					case "TimeSpan":
						return new NumberProperty(NumberType.Long);
					case "Single":
						return new NumberProperty(NumberType.Float);
					case "Decimal":
					case "Double":
					case "UInt64":
						return new NumberProperty(NumberType.Double);
					case "DateTime":
					case "DateTimeOffset":
						return new DateProperty();
					case "Boolean":
						return new BooleanProperty();
					case "Char":
					case "Guid":
						return new KeywordProperty();
				}
			}

			if (type == typeof(GeoLocation))
				return new GeoPointProperty();

			if (type == typeof(CompletionField))
				return new CompletionProperty();

			if (type == typeof(DateRange))
				return new DateRangeProperty();

			if (type == typeof(DoubleRange))
				return new DoubleRangeProperty();

			if (type == typeof(FloatRange))
				return new FloatRangeProperty();

			if (type == typeof(IntegerRange))
				return new IntegerRangeProperty();

			if (type == typeof(LongRange))
				return new LongRangeProperty();

			if (type == typeof(IpAddressRange))
				return new IpRangeProperty();

			if (type == typeof(QueryContainer))
				return new PercolatorProperty();

			if (type == typeof(IGeoShape))
				return new GeoShapeProperty();

			return new ObjectProperty();
		}

		/// <summary>
		/// Gets the underlying type when the type is a generic collection that implements <see cref="IEnumerable"/> or a nullable type
		/// </summary>
		private static Type GetUnderlyingType(Type type)
		{
			if (type.IsArray)
				return type.GetElementType();

			if (type.IsGenericType && type.GetGenericArguments().Length == 1
				&& (type.GetInterfaces().HasAny(t => t == typeof(IEnumerable)) || Nullable.GetUnderlyingType(type) != null))
				return type.GetGenericArguments()[0];

			return type;
		}
	}
}