using Lucene.Net.Index.Extensions;
using NUnit.Framework;
using System;
using Assert = Lucene.Net.TestFramework.Assert;

namespace Lucene.Net
{
    /*
     * Licensed to the Apache Software Foundation (ASF) under one or more
     * contributor license agreements.  See the NOTICE file distributed with
     * this work for additional information regarding copyright ownership.
     * The ASF 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 MockAnalyzer = Lucene.Net.Analysis.MockAnalyzer;
    using PostingsFormat = Lucene.Net.Codecs.PostingsFormat;
    using Lucene46Codec = Lucene.Net.Codecs.Lucene46.Lucene46Codec;
    using Document = Lucene.Net.Documents.Document;
    using Field = Lucene.Net.Documents.Field;
    using DirectoryReader = Lucene.Net.Index.DirectoryReader;
    using IndexReader = Lucene.Net.Index.IndexReader;
    using IndexWriter = Lucene.Net.Index.IndexWriter;
    using Term = Lucene.Net.Index.Term;
    using IndexSearcher = Lucene.Net.Search.IndexSearcher;
    using TermQuery = Lucene.Net.Search.TermQuery;
    using BaseDirectoryWrapper = Lucene.Net.Store.BaseDirectoryWrapper;
    using LuceneTestCase = Lucene.Net.Util.LuceneTestCase;

    /* Intentionally outside of oal.index to verify fully
       external codecs work fine */
    [TestFixture]
    public class TestExternalCodecs : LuceneTestCase
    {
        private sealed class CustomPerFieldCodec : Lucene46Codec
        {
            private readonly PostingsFormat ramFormat = PostingsFormat.ForName("RAMOnly");
            private readonly PostingsFormat defaultFormat = PostingsFormat.ForName("Lucene41");
            private readonly PostingsFormat pulsingFormat = PostingsFormat.ForName("Pulsing41");

            public override PostingsFormat GetPostingsFormatForField(string field)
            {
                if (field.Equals("field2", StringComparison.Ordinal) || field.Equals("id", StringComparison.Ordinal))
                {
                    return pulsingFormat;
                }
                else if (field.Equals("field1", StringComparison.Ordinal))
                {
                    return defaultFormat;
                }
                else
                {
                    return ramFormat;
                }
            }
        }

        // tests storing "id" and "field2" fields as pulsing codec,
        // whose term sort is backwards unicode code point, and
        // storing "field1" as a custom entirely-in-RAM codec
        [Test]
        public virtual void TestPerFieldCodec()
        {
            int NUM_DOCS = AtLeast(173);
            if (Verbose)
            {
                Console.WriteLine("TEST: NUM_DOCS=" + NUM_DOCS);
            }

            using BaseDirectoryWrapper dir = NewDirectory();
            dir.CheckIndexOnDispose = false; // we use a custom codec provider
            using IndexWriter w = new IndexWriter(
                dir,
                NewIndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(Random))
                    .SetCodec(new CustomPerFieldCodec())
                    .SetMergePolicy(NewLogMergePolicy(3)));
            Document doc = new Document();
            // uses default codec:
            doc.Add(NewTextField("field1", "this field uses the standard codec as the test", Field.Store.NO));
            // uses pulsing codec:
            Field field2 = NewTextField("field2", "this field uses the pulsing codec as the test", Field.Store.NO);
            doc.Add(field2);

            Field idField = NewStringField("id", "", Field.Store.NO);

            doc.Add(idField);
            for (int i = 0; i < NUM_DOCS; i++)
            {
                idField.SetStringValue("" + i);
                w.AddDocument(doc);
                if ((i + 1) % 10 == 0)
                {
                    w.Commit();
                }
            }
            if (Verbose)
            {
                Console.WriteLine("TEST: now delete id=77");
            }
            w.DeleteDocuments(new Term("id", "77"));

            using (IndexReader r = DirectoryReader.Open(w, true))
            {
                Assert.AreEqual(NUM_DOCS - 1, r.NumDocs);
                IndexSearcher s = NewSearcher(r);
                Assert.AreEqual(NUM_DOCS - 1, s.Search(new TermQuery(new Term("field1", "standard")), 1).TotalHits);
                Assert.AreEqual(NUM_DOCS - 1, s.Search(new TermQuery(new Term("field2", "pulsing")), 1).TotalHits);
            }

            if (Verbose)
            {
                Console.WriteLine("\nTEST: now delete 2nd doc");
            }
            w.DeleteDocuments(new Term("id", "44"));

            if (Verbose)
            {
                Console.WriteLine("\nTEST: now force merge");
            }
            w.ForceMerge(1);
            if (Verbose)
            {
                Console.WriteLine("\nTEST: now open reader");
            }
            using (IndexReader r = DirectoryReader.Open(w, true))
            {
                Assert.AreEqual(NUM_DOCS - 2, r.MaxDoc);
                Assert.AreEqual(NUM_DOCS - 2, r.NumDocs);
                IndexSearcher s = NewSearcher(r);
                Assert.AreEqual(NUM_DOCS - 2, s.Search(new TermQuery(new Term("field1", "standard")), 1).TotalHits);
                Assert.AreEqual(NUM_DOCS - 2, s.Search(new TermQuery(new Term("field2", "pulsing")), 1).TotalHits);
                Assert.AreEqual(1, s.Search(new TermQuery(new Term("id", "76")), 1).TotalHits);
                Assert.AreEqual(0, s.Search(new TermQuery(new Term("id", "77")), 1).TotalHits);
                Assert.AreEqual(0, s.Search(new TermQuery(new Term("id", "44")), 1).TotalHits);

                if (Verbose)
                {
                    Console.WriteLine("\nTEST: now close NRT reader");
                }
            }

            // LUCENENET specific - variables disposed above via `using` statements
            // w.Dispose();
            // dir.Dispose();
        }
    }
}