// (c) Copyright Ascensio System SIA 2010-2022
//
// This program is a free software product.
// You can redistribute it and/or modify it under the terms
// of the GNU Affero General Public License (AGPL) version 3 as published by the Free Software
// Foundation. In accordance with Section 7(a) of the GNU AGPL its Section 15 shall be amended
// to the effect that Ascensio System SIA expressly excludes the warranty of non-infringement of
// any third-party rights.
//
// This program is distributed WITHOUT ANY WARRANTY, without even the implied warranty
// of MERCHANTABILITY or FITNESS FOR A PARTICULAR  PURPOSE. For details, see
// the GNU AGPL at: http://www.gnu.org/licenses/agpl-3.0.html
//
// You can contact Ascensio System SIA at Lubanas st. 125a-25, Riga, Latvia, EU, LV-1021.
//
// The  interactive user interfaces in modified source and object code versions of the Program must
// display Appropriate Legal Notices, as required under Section 5 of the GNU AGPL version 3.
//
// Pursuant to Section 7(b) of the License you must retain the original Product logo when
// distributing the program. Pursuant to Section 7(e) we decline to grant you any rights under
// trademark law for use of our trademarks.
//
// All the Product's GUI elements, including illustrations and icon sets, as well as technical writing
// content are licensed under the terms of the Creative Commons Attribution-ShareAlike 4.0
// International. See the License terms at http://creativecommons.org/licenses/by-sa/4.0/legalcode

namespace ASC.ElasticSearch;

[Scope]
public class Selector<T> where T : class, ISearchItem
{
    private readonly IServiceProvider _serviceProvider;
    private readonly QueryContainerDescriptor<T> _queryContainerDescriptor = new QueryContainerDescriptor<T>();
    private SortDescriptor<T> _sortContainerDescriptor = new SortDescriptor<T>();
    private QueryContainer _queryContainer = new QueryContainer();
    private int _limit = 1000, _offset;

    public Selector(IServiceProvider serviceProvider)
    {
        _serviceProvider = serviceProvider;
    }

    public Selector<T> Where<TProperty>(Expression<Func<T, TProperty>> selector, TProperty value)
    {
        _queryContainer = _queryContainer && +Wrap(selector, (w, r) => r.Term(w, value));

        return this;
    }

    public Selector<T> Where(Expression<Func<T, Guid>> selector, Guid value)
    {
        _queryContainer = _queryContainer && +Wrap(selector, (a, w) => w.Match(r => r.Field(a).Query(value.ToString())));

        return this;
    }

    public Selector<T> Gt(Expression<Func<T, object>> selector, double? value)
    {
        _queryContainer = _queryContainer && +Wrap(selector, (w, r) => r.Range(a => a.Field(w).GreaterThan(value)));

        return this;
    }

    public Selector<T> Lt(Expression<Func<T, object>> selector, double? value)
    {
        _queryContainer = _queryContainer && +Wrap(selector, (w, r) => r.Range(a => a.Field(w).LessThan(value)));

        return this;
    }

    public Selector<T> Gt(Expression<Func<T, object>> selector, DateTime? value)
    {
        _queryContainer = _queryContainer && +Wrap(selector, (w, r) => r.DateRange(a => a.Field(w).GreaterThan(value)));

        return this;
    }

    public Selector<T> Ge(Expression<Func<T, object>> selector, DateTime? value)
    {
        _queryContainer = _queryContainer && +Wrap(selector, (w, r) => r.DateRange(a => a.Field(w).GreaterThanOrEquals(value)));

        return this;
    }

    public Selector<T> Lt(Expression<Func<T, object>> selector, DateTime? value)
    {
        _queryContainer = _queryContainer && +Wrap(selector, (w, r) => r.DateRange(a => a.Field(w).LessThan(value)));

        return this;
    }

    public Selector<T> Le(Expression<Func<T, object>> selector, DateTime? value)
    {
        _queryContainer = _queryContainer && +Wrap(selector, (w, r) => r.DateRange(a => a.Field(w).LessThanOrEquals(value)));

        return this;
    }

    public Selector<T> In<TValue>(Expression<Func<T, object>> selector, TValue[] values)
    {
        _queryContainer = _queryContainer && +Wrap(selector, (w, r) => r.Terms(a => a.Field(w).Terms(values)));

        return this;
    }

    public Selector<T> InAll<TValue>(Expression<Func<T, object>> selector, TValue[] values)
    {
        foreach (var v in values)
        {
            var v1 = v;
            _queryContainer = _queryContainer && +Wrap(selector, (w, r) => r.Term(a => a.Field(w).Value(v1)));
        }

        return this;
    }

    public Selector<T> Match(Expression<Func<T, object>> selector, string value)
    {
        value = value.PrepareToSearch();

        if (IsExactlyPhrase(value))
        {
            _queryContainer &= Wrap(selector, (a, w) => w.MatchPhrase(r => r.Field(a).Query(value.TrimQuotes())));
        }
        else if (value.HasOtherLetter() || IsExactly(value))
        {
            _queryContainer &= Wrap(selector, (a, w) => w.Match(r => r.Field(a).Query(value.TrimQuotes())));
        }
        else
        {
            if (IsPhrase(value))
            {
                var phrase = value.Split(' ');
                foreach (var p in phrase)
                {
                    var p1 = p;
                    _queryContainer &= Wrap(selector, (a, w) => w.Wildcard(r => r.Field(a).Value(p1.WrapAsterisk())));
                }
            }
            else
            {
                _queryContainer &= Wrap(selector, (a, w) => w.Wildcard(r => r.Field(a).Value(value.WrapAsterisk())));
            }

        }

        if (IsExactly(value))
        {
            _queryContainer |= Wrap(selector, (a, w) => w.MatchPhrase(r => r.Field(a).Query(value)));
        }

        return this;
    }

    public Selector<T> Match(Expression<Func<T, object[]>> selector, string value)
    {
        Match(() => ((NewArrayExpression)selector.Body).Expressions.ToArray(), value);

        return this;
    }

    public Selector<T> MatchAll(string value)
    {
        Match(() =>
        {
            var t = _serviceProvider.GetService<T>();
            var searchSettingsHelper = _serviceProvider.GetService<SearchSettingsHelper>();

            return ((NewArrayExpression)t.GetSearchContentFields(searchSettingsHelper).Body).Expressions.ToArray();
        },
        value);

        return this;
    }

    public Selector<T> Sort(Expression<Func<T, object>> selector, bool asc)
    {
        _sortContainerDescriptor = _sortContainerDescriptor.Field(selector, asc ? SortOrder.Ascending : SortOrder.Descending);

        return this;
    }

    public Selector<T> Limit(int newOffset = 0, int newLimit = 1000)
    {
        _offset = newOffset;
        _limit = newLimit;

        return this;
    }


    public Selector<T> Or(Expression<Func<Selector<T>, Selector<T>>> selectorLeft, Expression<Func<Selector<T>, Selector<T>>> selectorRight)
    {
        return new Selector<T>(_serviceProvider)
        {
            _queryContainer = _queryContainer &
                (selectorLeft.Compile()(new Selector<T>(_serviceProvider))._queryContainer |
                selectorRight.Compile()(new Selector<T>(_serviceProvider))._queryContainer)
        };
    }

    public static Selector<T> Or(Selector<T> selectorLeft, Selector<T> selectorRight)
    {
        return new Selector<T>(selectorLeft._serviceProvider)
        {
            _queryContainer = selectorLeft._queryContainer | selectorRight._queryContainer
        };
    }

    public Selector<T> Not(Expression<Func<Selector<T>, Selector<T>>> selector)
    {
        return new Selector<T>(_serviceProvider)
        {
            _queryContainer = _queryContainer & !selector.Compile()(new Selector<T>(_serviceProvider))._queryContainer
        };
    }

    public static Selector<T> Not(Selector<T> selector)
    {
        return new Selector<T>(selector._serviceProvider)
        {
            _queryContainer = !selector._queryContainer
        };
    }

    public static Selector<T> operator &(Selector<T> selectorLeft, Selector<T> selectorRight)
    {
        return new Selector<T>(selectorLeft._serviceProvider)
        {
            _queryContainer = selectorLeft._queryContainer & selectorRight._queryContainer
        };
    }

    public static Selector<T> operator |(Selector<T> selectorLeft, Selector<T> selectorRight)
    {
        return Or(selectorLeft, selectorRight);
    }

    public static Selector<T> operator !(Selector<T> selector)
    {
        return Not(selector);
    }

    internal Func<SearchDescriptor<T>, ISearchRequest> GetDescriptor(BaseIndexer<T> indexer, bool onlyId = false)
    {
        return s =>
        {
            var result = s
            .Query(q => _queryContainer)
            .Index(indexer.IndexName)
            .Sort(r => _sortContainerDescriptor)
            .From(_offset)
            .Size(_limit);

            if (onlyId)
            {
                result = result.Source(r => r.Includes(a => a.Field("id")));
            }

            return result;
        };
    }

    internal Func<DeleteByQueryDescriptor<T>, IDeleteByQueryRequest> GetDescriptorForDelete(BaseIndexer<T> indexer, bool immediately = true)
    {
        return s =>
        {
            var result = s
                .Query(q => _queryContainer)
                .Index(indexer.IndexName);
            if (immediately)
            {
                result.Refresh();
            }

            return result;
        };
    }

    internal Func<UpdateByQueryDescriptor<T>, IUpdateByQueryRequest> GetDescriptorForUpdate(BaseIndexer<T> indexer, Func<ScriptDescriptor, IScript> script, bool immediately = true)
    {
        return s =>
        {
            var result = s
                .Query(q => _queryContainer)
                .Index(indexer.IndexName)
                .Script(script);

            if (immediately)
            {
                result.Refresh();
            }

            return result;
        };
    }

    private void Match(Func<Fields> propsFunc, string value)
    {
        if (string.IsNullOrEmpty(value))
        {
            return;
        }

        value = value.PrepareToSearch();

        var props = propsFunc();

        if (IsExactlyPhrase(value))
        {
            _queryContainer = _queryContainer && MultiPhrase(props, value.TrimQuotes());
        }
        else if (value.HasOtherLetter() || IsExactly(value))
        {
            _queryContainer = _queryContainer && MultiMatch(props, value.TrimQuotes());
        }
        else
        {
            if (IsPhrase(value))
            {
                var phrase = value.Split(' ');
                foreach (var p in phrase)
                {
                    _queryContainer = _queryContainer && MultiWildCard(props, p.WrapAsterisk());
                }
            }
            else
            {
                _queryContainer = _queryContainer && MultiWildCard(props, value.WrapAsterisk());
            }
        }

        if (IsExactly(value))
        {
            _queryContainer = _queryContainer || MultiPhrase(props, value);
        }
    }

    private QueryContainer Wrap(Field fieldSelector, Func<Field, QueryContainerDescriptor<T>, QueryContainer> selector)
    {
        var path = IsNested(fieldSelector);

        if (string.IsNullOrEmpty(path) &&
            !string.IsNullOrEmpty(fieldSelector.Name) &&
            fieldSelector.Name.IndexOf('.') > -1)
        {
            var splitted = fieldSelector.Name.Split(':')[1];
            path = splitted.Split('.')[0];
            fieldSelector = new Field(splitted);
        }

        if (!string.IsNullOrEmpty(path))
        {
            return _queryContainerDescriptor.Nested(a => a.Query(b => selector(fieldSelector, b)).Path(path));
        }

        return selector(fieldSelector, _queryContainerDescriptor);
    }

    private string IsNested(Field selector)
    {
        if (selector.Expression is not LambdaExpression lambdaExpression)
        {
            return null;
        }

        if (lambdaExpression.Body is MethodCallExpression methodCallExpression && methodCallExpression.Arguments.Count > 1)
        {
            return methodCallExpression.Arguments[0] is not MemberExpression pathMember
                ? null
                : pathMember.Member.Name.ToLowerCamelCase();
        }

        return null;
    }

    private bool IsPhrase(string searchText)
    {
        return searchText.Contains(' ') || searchText.Contains("\r\n") || searchText.Contains('\n');
    }

    private bool IsExactlyPhrase(string searchText)
    {
        return IsPhrase(searchText) && IsExactly(searchText);
    }

    private bool IsExactly(string searchText)
    {
        return searchText.StartsWith('\"') && searchText.EndsWith('\"');
    }

    private QueryContainer MultiMatch(Fields fields, string value)
    {
        var qcWildCard = new QueryContainer();

        foreach (var field in fields)
        {
            var field1 = field;
            qcWildCard = qcWildCard || Wrap(field1, (a, w) => w.Match(r => r.Field(a).Query(value.ToLower())));
        }

        return qcWildCard;
    }

    private QueryContainer MultiWildCard(Fields fields, string value)
    {
        var qcWildCard = new QueryContainer();

        foreach (var field in fields)
        {
            qcWildCard = qcWildCard || Wrap(field, (a, w) => w.Wildcard(r => r.Field(a).Value(value)));
        }

        return qcWildCard;
    }

    private QueryContainer MultiPhrase(Fields fields, string value)
    {
        var qcWildCard = new QueryContainer();

        foreach (var field in fields)
        {
            qcWildCard = qcWildCard || Wrap(field, (a, w) => w.MatchPhrase(r => r.Field(a).Query(value.ToLower())));
        }

        return qcWildCard;
    }
}

internal static class StringExtension
{
    private static bool Any(this string value, UnicodeCategory category)
    {
        return !string.IsNullOrWhiteSpace(value)
        && value.Any(@char => char.GetUnicodeCategory(@char) == category);
    }

    public static bool HasOtherLetter(this string value)
    {
        return value.Any(UnicodeCategory.OtherLetter);
    }

    public static string WrapAsterisk(this string value)
    {
        var result = value;

        if (!value.Contains('*') && !value.Contains('?'))
        {
            result = "*" + result + "*";
        }

        return result;
    }

    public static string ReplaceBackslash(this string value)
    {
        return value.Replace("\\", "\\\\");
    }

    public static string TrimQuotes(this string value)
    {
        return value.Trim('\"');
    }

    public static string PrepareToSearch(this string value)
    {
        return value.ReplaceBackslash().ToLowerInvariant().Replace('ё', 'е').Replace('Ё', 'Е');
    }
}