using Microsoft.EntityFrameworkCore;
using ScadaLink.Commons.Entities.Templates;
using ScadaLink.ConfigurationDatabase;
using ScadaLink.ConfigurationDatabase.Repositories;

namespace ScadaLink.ConfigurationDatabase.Tests;

public class TemplateEngineRepositoryTests : IDisposable
{
    private readonly ScadaLinkDbContext _context;
    private readonly TemplateEngineRepository _repository;

    public TemplateEngineRepositoryTests()
    {
        var options = new DbContextOptionsBuilder<ScadaLinkDbContext>()
            .UseSqlite("DataSource=:memory:")
            .Options;

        _context = new ScadaLinkDbContext(options);
        _context.Database.OpenConnection();
        _context.Database.EnsureCreated();
        _repository = new TemplateEngineRepository(_context);
    }

    public void Dispose()
    {
        _context.Database.CloseConnection();
        _context.Dispose();
    }

    [Fact]
    public async Task GetTemplateWithChildrenAsync_ReturnsTemplateWithAllMemberCollectionsPopulated()
    {
        // Arrange: a template with one attribute, one alarm, one script and one composition.
        var composed = new Template("ComposedTemplate");
        _context.Templates.Add(composed);
        await _context.SaveChangesAsync();

        var template = new Template("ParentTemplate");
        template.Attributes.Add(new TemplateAttribute("Attr1"));
        template.Alarms.Add(new TemplateAlarm("Alarm1"));
        template.Scripts.Add(new TemplateScript("Script1", "return 1;"));
        template.Compositions.Add(new TemplateComposition("Slot1") { ComposedTemplateId = composed.Id });
        _context.Templates.Add(template);
        await _context.SaveChangesAsync();

        // Act
        var loaded = await _repository.GetTemplateWithChildrenAsync(template.Id);

        // Assert: the method must deliver the template's child members to the caller,
        // not silently drop them. Regression guard for ConfigurationDatabase-001.
        Assert.NotNull(loaded);
        Assert.Equal(template.Id, loaded!.Id);
        Assert.Single(loaded.Attributes);
        Assert.Equal("Attr1", loaded.Attributes.First().Name);
        Assert.Single(loaded.Alarms);
        Assert.Equal("Alarm1", loaded.Alarms.First().Name);
        Assert.Single(loaded.Scripts);
        Assert.Equal("Script1", loaded.Scripts.First().Name);
        Assert.Single(loaded.Compositions);
        Assert.Equal("Slot1", loaded.Compositions.First().InstanceName);
    }

    [Fact]
    public async Task GetTemplateWithChildrenAsync_ReturnsNull_WhenTemplateDoesNotExist()
    {
        var loaded = await _repository.GetTemplateWithChildrenAsync(9999);

        Assert.Null(loaded);
    }

    [Fact]
    public async Task GetTemplatesWithChildrenAsync_BulkVariant_FetchesEveryMatchingNameInOneQuery()
    {
        // Transport-008 regression: BundleImporter.PreviewAsync previously
        // called GetTemplateWithChildrenAsync(stub.Id) per matching template
        // name. The bulk variant returns every match in a single query.
        var a = new Template("Alpha");
        a.Attributes.Add(new TemplateAttribute("A1"));
        a.Scripts.Add(new TemplateScript("AS1", "return 1;"));
        var b = new Template("Beta");
        b.Alarms.Add(new TemplateAlarm("BAlarm"));
        var c = new Template("Gamma");
        _context.Templates.AddRange(a, b, c);
        await _context.SaveChangesAsync();

        var result = await _repository.GetTemplatesWithChildrenAsync(new[] { "Alpha", "Beta", "DoesNotExist" });

        Assert.Equal(2, result.Count);
        var loadedA = Assert.Single(result, t => t.Name == "Alpha");
        var loadedB = Assert.Single(result, t => t.Name == "Beta");
        Assert.Single(loadedA.Attributes);
        Assert.Equal("A1", loadedA.Attributes.First().Name);
        Assert.Single(loadedA.Scripts);
        Assert.Single(loadedB.Alarms);
        Assert.Equal("BAlarm", loadedB.Alarms.First().Name);
        Assert.DoesNotContain(result, t => t.Name == "Gamma");
    }

    [Fact]
    public async Task GetTemplatesWithChildrenAsync_EmptyNames_ReturnsEmpty()
    {
        var result = await _repository.GetTemplatesWithChildrenAsync(Array.Empty<string>());

        Assert.Empty(result);
    }

    [Fact]
    public async Task GetTemplatesWithChildrenAsync_NullEnumerable_ReturnsEmpty()
    {
        var result = await _repository.GetTemplatesWithChildrenAsync(null!);

        Assert.Empty(result);
    }

    [Fact]
    public async Task GetTemplatesWithChildrenAsync_FiltersOutDuplicatesAndEmptyStrings()
    {
        var a = new Template("Alpha");
        _context.Templates.Add(a);
        await _context.SaveChangesAsync();

        // Duplicate names + empty / null entries should not throw; the helper
        // deduplicates and filters them out before the SQL IN clause.
        var result = await _repository.GetTemplatesWithChildrenAsync(
            new[] { "Alpha", "Alpha", "", null!, "Alpha" });

        Assert.Single(result);
        Assert.Equal("Alpha", result[0].Name);
    }

    [Fact]
    public async Task GetTemplateWithChildrenAsync_PreservesParentTemplateId_ForInheritanceChainWalk()
    {
        // FlatteningPipeline.BuildTemplateChainAsync walks ParentTemplateId upward.
        // The result of GetTemplateWithChildrenAsync must carry that link intact.
        var baseTemplate = new Template("BaseTemplate");
        _context.Templates.Add(baseTemplate);
        await _context.SaveChangesAsync();

        var derived = new Template("DerivedTemplate") { ParentTemplateId = baseTemplate.Id };
        _context.Templates.Add(derived);
        await _context.SaveChangesAsync();

        var loaded = await _repository.GetTemplateWithChildrenAsync(derived.Id);

        Assert.NotNull(loaded);
        Assert.Equal(baseTemplate.Id, loaded!.ParentTemplateId);
    }
}