using System.Text.Json;
using ClawdDotNet.Core.Backup;
using ClawdDotNet.Core.Config;
using ClawdDotNet.Core.Instances;
using Microsoft.Extensions.Logging.Abstractions;
using Shouldly;

namespace ClawdDotNet.Manager.Tests;

/// <summary>
/// #764: A backup uploaded in the WebUI becomes a new instance — the move to a fresh machine,
/// which only the desktop restore window could do before.
/// </summary>
public sealed class BackupImportTests : IAsyncDisposable
{
    private const string License = "CLAWD-TEST-0000-1111-2222";
    private const string ForeignLicense = "CLAWD-TEST-9999-8888-7777";

    private readonly string _root = Path.Combine(
        Path.GetTempPath(), "clawd-tests", "mimp-" + Guid.NewGuid().ToString("N")[..8]);

    private readonly InstanceDirectoryManager _directories;
    private readonly ManagerSettingsStore _settings;

    public BackupImportTests()
    {
        Directory.CreateDirectory(_root);
        _directories = new InstanceDirectoryManager(Path.Combine(_root, "Instances"));
        _settings = new ManagerSettingsStore(_root);
        _settings.Settings.LicenseKey = License;
    }

    public async ValueTask DisposeAsync()
    {
        await Task.CompletedTask;
        ClawdDotNet.Core.Storage.SqliteStorage.ReleasePooledConnections(_root);
        try { Directory.Delete(_root, recursive: true); }
        catch { /* A leftover test folder does not turn a run red. */ }
    }

    private async Task<(ManagerBackups Backups, InstanceRegistry Registry)> ServiceAsync()
    {
        var registry = new InstanceRegistry(
            _directories, new FakeLauncher(), new FakeChannel(), NullLoggerFactory.Instance,
            SupervisionOptions.Default);
        await registry.RefreshAsync();
        return (new ManagerBackups(_settings, registry, null, NullLogger.Instance), registry);
    }

    /// <summary>An instance with paths of "another machine" and autostart on, backed up and then removed.</summary>
    private async Task<(string Archive, string InstanceId)> BackupOfAnInstanceAsync(string name, bool removeOriginal = true)
    {
        var path = _directories.CreateInstance(name);
        var file = Path.Combine(path, "InstanceSettings.json");
        var config = JsonSerializer.Deserialize<InstanceConfig>(File.ReadAllText(file))!;
        config.AutostartByManager = true;
        config.LogDirectory = Path.Combine(_root, "elsewhere", "logs");
        config.BackupDirectory = Path.Combine(_root, "elsewhere", "backups");
        File.WriteAllText(file, JsonSerializer.Serialize(config));

        var (backups, registry) = await ServiceAsync();
        await using (backups)
        await using (registry)
        {
            var instance = registry.Instances.Single(i => PathEquals(i.Directory, path));
            var outcome = await backups.CreateAsync(instance, false, true, CancellationToken.None);

            var archive = Path.Combine(_root, "upload-" + Guid.NewGuid().ToString("N") + ".bak");
            File.Copy(outcome.Path, archive);

            if (removeOriginal)
            {
                await registry.DisposeAsync();
                ClawdDotNet.Core.Storage.SqliteStorage.ReleasePooledConnections(_root);
                Directory.Delete(path, recursive: true);
            }

            return (archive, config.InstanceId);
        }
    }

    private static bool PathEquals(string a, string b)
        => ClawdDotNet.Core.Storage.PathBoundary.Comparer.Equals(Path.GetFullPath(a), Path.GetFullPath(b));

    [Fact]
    public async Task A_backup_becomes_a_new_instance_with_its_own_paths()
    {
        var (archive, id) = await BackupOfAnInstanceAsync("Alpha");

        var (backups, registry) = await ServiceAsync();
        await using var _ = backups;
        await using var __ = registry;

        var result = await backups.ImportAsNewInstanceAsync(archive, "Moved", null, null);

        result.Ok.ShouldBeTrue(result.Message);
        var config = _directories.LoadInstanceConfig(result.Directory!);
        config.InstanceName.ShouldBe("Moved");
        config.InstanceId.ShouldBe(id);                 // a move keeps its identity
        PathEquals(config.WorkingDirectory, result.Directory!).ShouldBeTrue();
        config.LogDirectory.ShouldBeEmpty();
        config.BackupDirectory.ShouldBeEmpty();
        config.AutostartByManager.ShouldBeFalse();
        registry.Instances.ShouldContain(i => PathEquals(i.Directory, result.Directory!));
    }

    [Fact]
    public async Task A_copy_next_to_its_original_gets_a_new_id()
    {
        // Two instances with one id would report as one and share one reporting token.
        var (archive, id) = await BackupOfAnInstanceAsync("Alpha", removeOriginal: false);

        var (backups, registry) = await ServiceAsync();
        await using var _ = backups;
        await using var __ = registry;

        var result = await backups.ImportAsNewInstanceAsync(archive, "Alpha-Copy", null, null);

        result.Ok.ShouldBeTrue(result.Message);
        var config = _directories.LoadInstanceConfig(result.Directory!);
        config.InstanceId.ShouldNotBe(id);
        config.Watchdog.AgentToken.ShouldBeEmpty();
    }

    [Fact]
    public async Task An_existing_instance_is_never_overwritten()
    {
        var (archive, _) = await BackupOfAnInstanceAsync("Alpha");
        _directories.CreateInstance("Taken");

        var (backups, registry) = await ServiceAsync();
        await using var a = backups;
        await using var b = registry;

        (await backups.ImportAsNewInstanceAsync(archive, "Taken", null, null)).Ok.ShouldBeFalse();
    }

    [Fact]
    public async Task A_foreign_backup_asks_for_its_key_and_leaves_nothing_behind()
    {
        var (archive, _) = await BackupOfAnInstanceAsync("Alpha");
        _settings.Settings.LicenseKey = ForeignLicense;   // now this is "another installation"

        var (backups, registry) = await ServiceAsync();
        await using var a = backups;
        await using var b = registry;

        var refused = await backups.ImportAsNewInstanceAsync(archive, "Moved", null, null);
        refused.KeyNeeded.ShouldBeTrue();
        Directory.Exists(_directories.GetInstancePath("Moved")).ShouldBeFalse();

        var accepted = await backups.ImportAsNewInstanceAsync(archive, "Moved", License, null);
        accepted.Ok.ShouldBeTrue(accepted.Message);
    }

    [Fact]
    public async Task A_broken_file_leaves_no_half_instance()
    {
        var junk = Path.Combine(_root, "junk.bak");
        await File.WriteAllBytesAsync(junk, [1, 2, 3, 4, 5]);

        var (backups, registry) = await ServiceAsync();
        await using var a = backups;
        await using var b = registry;

        (await backups.ImportAsNewInstanceAsync(junk, "Broken", null, null)).Ok.ShouldBeFalse();
        Directory.Exists(_directories.GetInstancePath("Broken")).ShouldBeFalse();
    }
}