using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;
using ZB.MOM.WW.ScadaBridge.Commons.Entities.Audit;
using ZB.MOM.WW.ScadaBridge.ConfigurationDatabase.Maintenance;

namespace ZB.MOM.WW.ScadaBridge.ConfigurationDatabase.Tests.Maintenance;

/// <summary>Tests for the opt-in config-audit retention purge (review 2026-10-21 08/G1).</summary>
public class ConfigAuditPurgeServiceTests : IDisposable
{
    private readonly ScadaBridgeDbContext _context = SqliteTestHelper.CreateInMemoryContext();

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

    private ConfigAuditPurgeService Create(ConfigAuditOptions opts)
    {
        var services = new ServiceCollection();
        services.AddSingleton(_context);
        return new ConfigAuditPurgeService(
            services.BuildServiceProvider().GetRequiredService<IServiceScopeFactory>(),
            Options.Create(opts),
            TimeProvider.System,
            NullLogger<ConfigAuditPurgeService>.Instance);
    }

    private async Task SeedAsync(int oldCount, int recentCount)
    {
        var now = DateTimeOffset.UtcNow;
        for (var i = 0; i < oldCount; i++)
            _context.AuditLogEntries.Add(new AuditLogEntry("u", "Create", "Template", $"o{i}", $"Old{i}") { Timestamp = now.AddDays(-100).AddMinutes(i) });
        for (var i = 0; i < recentCount; i++)
            _context.AuditLogEntries.Add(new AuditLogEntry("u", "Create", "Template", $"r{i}", $"New{i}") { Timestamp = now.AddDays(-1) });
        await _context.SaveChangesAsync();
    }

    [Fact]
    public async Task RetentionZero_DeletesNothing()
    {
        await SeedAsync(5, 2);
        var deleted = await Create(new ConfigAuditOptions { RetentionDays = 0 }).PurgeOnceAsync();
        Assert.Equal(0, deleted);
        Assert.Equal(7, _context.AuditLogEntries.Count());
    }

    [Fact]
    public async Task Retention_DeletesOnlyOlderThanWindow_AcrossBatches()
    {
        await SeedAsync(25, 3);
        var deleted = await Create(new ConfigAuditOptions { RetentionDays = 30, PurgeBatchSize = 10 }).PurgeOnceAsync();
        Assert.Equal(25, deleted);
        Assert.Equal(3, _context.AuditLogEntries.Count());
    }

    [Fact]
    public async Task Retention_MaxBatchesPerTick_TimeSlicesTheBacklog()
    {
        await SeedAsync(25, 0);
        var svc = Create(new ConfigAuditOptions { RetentionDays = 30, PurgeBatchSize = 10, MaxBatchesPerTick = 2 });
        Assert.Equal(20, await svc.PurgeOnceAsync());
        Assert.Equal(5, await svc.PurgeOnceAsync());
    }

    [Fact]
    public void Validator_RejectsNegativeRetention_AcceptsZero()
    {
        var v = new ConfigAuditOptionsValidator();
        Assert.True(v.Validate(null, new ConfigAuditOptions { RetentionDays = 0 }).Succeeded);
        Assert.True(v.Validate(null, new ConfigAuditOptions { RetentionDays = 90 }).Succeeded);
        Assert.False(v.Validate(null, new ConfigAuditOptions { RetentionDays = -1 }).Succeeded);
        Assert.False(v.Validate(null, new ConfigAuditOptions { PurgeBatchSize = 0 }).Succeeded);
    }
}