// Copyright (C) 2025, The Duplicati Team
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// 
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// 
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using System.IO;
using NUnit.Framework;
using System.Linq;
using System;
using NUnit.Framework.Internal;
using System.IO.Compression;
using Duplicati.Library.DynamicLoader;

namespace Duplicati.UnitTest
{
    public class Issue6254 : BasicSetupHelper
    {
        [Test]
        [Category("Targeted")]
        public void VerifyCompactKeepsIndexFileBlocklists()
        {
            var testopts = TestOptions.Expand(new
            {
                no_encryption = true,
                number_of_retries = 0,
                keep_versions = 1,
                no_auto_compact = true,
                zip_compression_level = 0,
                asynchronous_upload_limit = 1,
                blocksize = "100kb",
                dblock_size = "4mb"
            });

            var rnd = Random.Shared; //new Random(42);
            var data1 = new byte[1024 * 1024 * 10];
            rnd.NextBytes(data1);
            var data2 = new byte[1024 * 1024 * 10];
            rnd.NextBytes(data2);

            // Create some files
            for (var i = 0; i < 10; i++)
                File.WriteAllBytes(Path.Combine(DATAFOLDER, $"a{i}"), data1.AsSpan().Slice(i, 1024 * 1024 * 2).ToArray());

            // Make a backup
            using (var c = new Library.Main.Controller("file://" + TARGETFOLDER, testopts, null))
                TestUtils.AssertResults(c.Backup(new string[] { DATAFOLDER }));

            // Add some second files
            for (var i = 0; i < 10; i++)
                File.WriteAllBytes(Path.Combine(DATAFOLDER, $"b{i}"), data2.AsSpan().Slice(i, 1024 * 1024 * 2).ToArray());

            // Make a backup
            using (var c = new Library.Main.Controller("file://" + TARGETFOLDER, testopts, null))
                TestUtils.AssertResults(c.Backup(new string[] { DATAFOLDER }));

            // Delete the first files
            for (var i = 0; i < 8; i++)
                File.Delete(Path.Combine(DATAFOLDER, $"a{i}"));

            var indexfiles = Directory.GetFiles(TARGETFOLDER, "*.dindex.*", SearchOption.TopDirectoryOnly).ToHashSet();

            // Make a backup
            using (var c = new Library.Main.Controller("file://" + TARGETFOLDER, testopts, null))
                TestUtils.AssertResults(c.Backup(new string[] { DATAFOLDER }));

            // Now run compact
            using (var c = new Library.Main.Controller("file://" + TARGETFOLDER, testopts, null))
                TestUtils.AssertResults(c.Compact());

            // Find the new index files
            var newIndexFiles = Directory.GetFiles(TARGETFOLDER, "*.dindex.*", SearchOption.TopDirectoryOnly)
                .Where(x => !indexfiles.Contains(x))
                .ToList();

            Assert.That(newIndexFiles.Count, Is.GreaterThan(0), "No new index files found");

            // Check that the new index files contains the list folder
            var matches = 0;
            foreach (var file in newIndexFiles)
            {
                using var zip = new ZipArchive(File.OpenRead(file), ZipArchiveMode.Read);
                if (zip.Entries.Any(x => x.FullName.StartsWith("list/")))
                    matches++;
            }

            // Test is essentially inconclusive here, as the repair does not cover the blocklist hashes
            // but we cannot control it closely enough to make it always work
            //Assert.That(matches, Is.EqualTo(newIndexFiles.Count), "No new index files found with list folder");

            // Check that recreate does not load dblock files
            BackendLoader.AddBackend(new DeterministicErrorBackend());
            File.Delete(DBFILE);

            DeterministicErrorBackend.ErrorGenerator = (action, remotename) =>
            {
                if (action.IsGetOperation && remotename.Contains(".dblock."))
                    return true;
                return false;
            };

            using (var c = new Library.Main.Controller(new DeterministicErrorBackend().ProtocolKey + "://" + TARGETFOLDER, testopts, null))
                TestUtils.AssertResults(c.Repair());
        }
    }
}