Masuit.LuceneEFCore.SearchEngine/Masuit.LuceneEFCore.SearchEngine/SearchOptions.cs

using Lucene.Net.Search;
using Masuit.LuceneEFCore.SearchEngine.Extensions;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;

namespace Masuit.LuceneEFCore.SearchEngine
{
    /// <summary>
    /// 搜索选项
    /// </summary>
    public class SearchOptions
    {
        /// <summary>
        /// 关键词
        /// </summary>
        public string Keywords { get; set; }

        /// <summary>
        /// 限定搜索字段
        /// </summary>
        public List<string> Fields { get; set; }

        /// <summary>
        /// 最大检索量
        /// </summary>
        public int MaximumNumberOfHits { get; set; }

        /// <summary>
        /// 多字段搜索时，给字段设定搜索权重
        /// </summary>
        private readonly Dictionary<string, float> _boosts;

        /// <summary>
        /// 多字段搜索时，给字段设定搜索权重
        /// </summary>
        internal Dictionary<string, float> Boosts
        {
            get
            {
                foreach (var field in Fields.Where(field => _boosts.All(x => x.Key.ToUpper() != field.ToUpper())))
                {
                    _boosts.Add(field, 2.0f);
                }

                return _boosts;
            }
        }

        /// <summary>
        /// 排序字段
        /// </summary>
        public List<SortField> OrderBy { get; set; }

        /// <summary>
        /// 跳过多少条
        /// </summary>
        public int? Skip { get; set; }

        /// <summary>
        /// 取多少条
        /// </summary>
        public int? Take { get; set; }

        /// <summary>
        /// 文档类型
        /// </summary>
        public Type Type { get; set; }

        /// <summary>
        /// 匹配度，0-1，数值越大结果越精确
        /// </summary>
        public float Score { get; set; } = 0.5f;

        /// <summary>
        /// 过滤条件
        /// </summary>
        public Filter Filter { get; set; }

        /// <summary>
        /// 搜索选项
        /// </summary>
        /// <param name="keywords">关键词</param>
        /// <param name="fields">限定检索字段</param>
        /// <param name="maximumNumberOfHits">最大检索量</param>
        /// <param name="boosts">多字段搜索时，给字段设定搜索权重</param>
        /// <param name="type">文档类型</param>
        /// <param name="orderBy">排序字段</param>
        /// <param name="skip">跳过多少条</param>
        /// <param name="take">取多少条</param>
        public SearchOptions(string keywords, string fields, int maximumNumberOfHits = 1000, Dictionary<string, float> boosts = null, Type type = null, string orderBy = null, int? skip = null, int? take = null)
        {
            if (string.IsNullOrWhiteSpace(keywords))
            {
                throw new ArgumentException("搜索关键词不能为空！");
            }

            Keywords = keywords;
            MaximumNumberOfHits = maximumNumberOfHits;
            Skip = skip;
            Take = take;
            _boosts = boosts ?? new Dictionary<string, float>();
            Type = type;
            Fields = new List<string>();
            OrderBy = new List<SortField>()
            {
                SortField.FIELD_SCORE
            };

            // 添加被检索字段
            if (!string.IsNullOrEmpty(fields))
            {
                fields = fields.RemoveCharacters(" ");
                Fields.AddRange(fields.Split(',').ToList());
            }

            // 添加排序规则
            if (!string.IsNullOrEmpty(orderBy))
            {
                orderBy = orderBy.RemoveCharacters(" ");
                OrderBy.AddRange(orderBy.Split(',').Select(sortField => new SortField(sortField, SortFieldType.STRING)));
            }
        }

        /// <summary>
        /// 搜索选项
        /// </summary>
        /// <param name="keywords">关键词</param>
        /// <param name="size">页大小</param>
        /// <param name="fields">限定检索字段</param>
        /// <param name="page">第几页</param>
        public SearchOptions(string keywords, int page, int size, string fields) : this(keywords, fields, int.MaxValue, null, null, null, (page - 1) * size, size)
        {
            if (page < 1)
            {
                page = 1;
            }
            if (size < 1)
            {
                size = 1;
            }
            Skip = (page - 1) * size;
            Take = size;
        }

        /// <summary>
        /// 搜索选项
        /// </summary>
        /// <param name="keywords">关键词</param>
        /// <param name="size">页大小</param>
        /// <param name="page">第几页</param>
        /// <param name="t">需要被全文检索的类型</param>
        public SearchOptions(string keywords, int page, int size, Type t) : this(keywords, string.Join(",", t.GetProperties().Where(p => p.GetCustomAttributes<LuceneIndexAttribute>().Any()).Select(p => p.Name)), int.MaxValue, null, null, null, (page - 1) * size, size)
        {
            if (page < 1)
            {
                page = 1;
            }
            if (size < 1)
            {
                size = 1;
            }
            Skip = (page - 1) * size;
            Take = size;
        }

        public void SetBoosts(string field, float boost)
        {
            _boosts[field] = boost;
        }
    }
}