using System.Net.Http.Json;
using ItWorx.KnowledgeHub.Application.Operations;
using ItWorx.KnowledgeHub.Contracts.Knowledge;
using ItWorx.KnowledgeHub.Infrastructure.Operations;
using ItWorx.KnowledgeHub.Infrastructure.Persistence;
using ItWorx.KnowledgeHub.IntegrationTests.Infrastructure;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;

namespace ItWorx.KnowledgeHub.IntegrationTests.Operations;

/// <summary>Proves M7-A03 ("A full backup captures database, attachments, manifest and
/// integrity hashes") against a real running application and real PostgreSQL, not a
/// mock.</summary>
[Collection(PostgresTestGroup.Name)]
public sealed class BackupServiceTests : OwnerSetupTestBase
{
    private readonly PostgresContainerFixture _postgres;

    public BackupServiceTests(PostgresContainerFixture postgres)
        : base(postgres, new Dictionary<string, string?> { ["KnowledgeHub:Backup:RetainedCount"] = "2" })
    {
        _postgres = postgres;
    }

    [Fact]
    public async Task A_backup_captures_every_table_and_verifies_its_own_hashes()
    {
        using var client = Factory.CreateClient();
        await SetupHelper.LoginAsync(client, OwnerEmail, OwnerPassword);
        await SetupHelper.PostWithCsrfAsync(
            client, "/api/v1/pages", new CreatePageRequest(null, "Back-uptestpagina", "WikiPage", "Inhoud.", null));

        using var scope = Factory.Services.CreateScope();
        var backups = scope.ServiceProvider.GetRequiredService<IBackupService>();
        var database = scope.ServiceProvider.GetRequiredService<KnowledgeHubDbContext>();
        var appliedMigrations = await database.Database.GetAppliedMigrationsAsync();
        Assert.NotEmpty(appliedMigrations);
        var latestAppliedMigration = appliedMigrations.Last();

        var summary = await backups.CreateBackupAsync(CancellationToken.None);

        Assert.True(summary.TableCount > 0);
        Assert.True(summary.TotalRowCount > 0);

        var manifest = await backups.GetManifestAsync(summary.BackupId, CancellationToken.None);
        Assert.NotNull(manifest);
        Assert.Equal(latestAppliedMigration, manifest.SchemaVersion);
        var pagesTable = Assert.Single(manifest.Tables, table => table.TableName == "pages");
        Assert.True(pagesTable.RowCount >= 1);
        Assert.False(string.IsNullOrWhiteSpace(pagesTable.Sha256));
        // Never a migration-bookkeeping table — that is recreated by the target's own
        // startup migration, not restored as user data (ADR-016 decision 2).
        Assert.DoesNotContain(manifest.Tables, table => table.TableName == "__EFMigrationsHistory");
        var receipt = await scope.ServiceProvider.GetRequiredService<IBackupEvidenceStore>().GetAsync(summary.BackupId, CancellationToken.None);
        Assert.NotNull(receipt!.IntegrityVerifiedAt);
        Assert.Null(receipt.RestoreVerifiedAt);
        AssertBackupFilesArePrivate(
            scope.ServiceProvider.GetRequiredService<BackupPaths>(), summary.BackupId);

        // Restore the binary dump into a separate migrated database and verify every
        // manifest row count against the rows actually written by PostgreSQL COPY.
        await using var target = await RestoreTargetDatabase.CreateAsync(_postgres);
        var restore = scope.ServiceProvider.GetRequiredService<IRestoreService>();
        var report = await restore.RestoreAsync(
            summary.BackupId,
            new RestoreTarget(target.ConnectionString, target.AttachmentsDirectory),
            CancellationToken.None);
        Assert.True(report.Success, string.Join("; ", report.Warnings));
        Assert.All(report.Tables, table => Assert.True(
            table.Matches,
            $"{table.TableName}: restored {table.RestoredRowCount}, manifest expected {table.ExpectedRowCount}"));
    }

    [Fact]
    public async Task A_backup_includes_uploaded_attachments_with_verified_hashes()
    {
        using var client = Factory.CreateClient();
        await SetupHelper.LoginAsync(client, OwnerEmail, OwnerPassword);
        var pageResponse = await SetupHelper.PostWithCsrfAsync(
            client, "/api/v1/pages", new CreatePageRequest(null, "Pagina met bijlage", "WikiPage", "Inhoud.", null));
        var page = await pageResponse.Content.ReadFromJsonAsync<PageDetail>();
        Assert.NotNull(page);

        var uploadResponse = await SetupHelper.PostMultipartWithCsrfAsync(
            client,
            $"/api/v1/pages/{page.Id}/attachments",
            "Testbestand voor back-up."u8.ToArray(),
            "backup-test.txt",
            "text/plain");
        Assert.True(uploadResponse.IsSuccessStatusCode);

        using var scope = Factory.Services.CreateScope();
        var backups = scope.ServiceProvider.GetRequiredService<IBackupService>();
        var summary = await backups.CreateBackupAsync(CancellationToken.None);

        Assert.Equal(1, summary.AttachmentCount);
        var manifest = await backups.GetManifestAsync(summary.BackupId, CancellationToken.None);
        Assert.NotNull(manifest);
        Assert.Single(manifest.Attachments);
    }

    [Fact]
    public async Task Listing_backups_returns_newest_first_and_retention_prunes_older_ones()
    {
        using var scope = Factory.Services.CreateScope();
        var backups = scope.ServiceProvider.GetRequiredService<IBackupService>();

        var first = await backups.CreateBackupAsync(CancellationToken.None);
        var second = await backups.CreateBackupAsync(CancellationToken.None);
        var third = await backups.CreateBackupAsync(CancellationToken.None);

        var list = await backups.ListBackupsAsync(CancellationToken.None);

        // Configured KnowledgeHub:Backup:RetainedCount = 2 for this test class.
        Assert.Equal(2, list.Count);
        Assert.Equal(third.BackupId, list[0].BackupId);
        Assert.Equal(second.BackupId, list[1].BackupId);
        Assert.DoesNotContain(list, entry => entry.BackupId == first.BackupId);
    }

    [Fact]
    public async Task Protected_backup_survives_retention_of_newer_unprotected_copies()
    {
        using var scope = Factory.Services.CreateScope();
        var backups = scope.ServiceProvider.GetRequiredService<IBackupService>();
        var evidence = scope.ServiceProvider.GetRequiredService<IBackupEvidenceStore>();
        var protectedBackup = await backups.CreateBackupAsync(CancellationToken.None);
        Assert.Equal(BackupProtectionResult.Updated,
            await evidence.SetProtectionAsync(protectedBackup.BackupId, true, 0, Guid.NewGuid(), CancellationToken.None));
        await backups.CreateBackupAsync(CancellationToken.None);
        await backups.CreateBackupAsync(CancellationToken.None);
        var latest = await backups.CreateBackupAsync(CancellationToken.None);
        var list = await backups.ListBackupsAsync(CancellationToken.None);
        Assert.Contains(list, backup => backup.BackupId == protectedBackup.BackupId);
        Assert.Contains(list, backup => backup.BackupId == latest.BackupId);
        Assert.Equal(3, list.Count);
    }

    private static void AssertBackupFilesArePrivate(BackupPaths paths, string backupId)
    {
        if (OperatingSystem.IsWindows()) return;

        var backupDirectory = Path.Combine(paths.BackupsRoot, backupId);
        Assert.Equal(
            UnixFileMode.UserRead | UnixFileMode.UserWrite | UnixFileMode.UserExecute,
            File.GetUnixFileMode(paths.BackupsRoot));
        var directories = Directory.EnumerateDirectories(backupDirectory, "*", SearchOption.AllDirectories)
            .Prepend(backupDirectory);
        foreach (var directory in directories)
        {
            Assert.Equal(
                UnixFileMode.UserRead | UnixFileMode.UserWrite | UnixFileMode.UserExecute,
                File.GetUnixFileMode(directory));
        }

        foreach (var file in Directory.EnumerateFiles(backupDirectory, "*", SearchOption.AllDirectories))
        {
            Assert.Equal(UnixFileMode.UserRead | UnixFileMode.UserWrite, File.GetUnixFileMode(file));
        }

        Assert.Equal(
            UnixFileMode.UserRead | UnixFileMode.UserWrite,
            File.GetUnixFileMode(Path.Combine(paths.BackupsRoot, ".backup.lock")));
    }
}