using FluentAssertions;
using InboxIntel.Application.Abstractions;
using InboxIntel.Domain.Entities;
using InboxIntel.Infrastructure.Configuration;
using InboxIntel.Infrastructure.Persistence;
using InboxIntel.Infrastructure.Retention;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;
using Xunit;

namespace InboxIntel.IntegrationTests;

/// <summary>
/// AUDIT H-3 (retention): the purge removes only what the configuration targets and is a
/// no-op while disabled — locking the "no behaviour change until opted in" guarantee.
/// </summary>
public class RetentionServiceTests
{
    private sealed class FakeCurrentUser : ICurrentUser
    {
        public Guid UserId => Guid.Empty; // worker scope
        public bool IsAuthenticated => false;
    }

    private static AppDbContext NewDb(string name) =>
        new(new DbContextOptionsBuilder<AppDbContext>().UseInMemoryDatabase(name).Options, new FakeCurrentUser());

    private static async Task SeedAsync(AppDbContext db)
    {
        var user = Guid.NewGuid();
        db.Emails.AddRange(
            new Email { UserId = user, GmailMessageId = "old-trashed", IsTrashed = true, SentAtUtc = DateTimeOffset.UtcNow.AddDays(-100) },
            new Email { UserId = user, GmailMessageId = "new-trashed", IsTrashed = true, SentAtUtc = DateTimeOffset.UtcNow.AddDays(-5) },
            new Email { UserId = user, GmailMessageId = "old-kept", IsTrashed = false, SentAtUtc = DateTimeOffset.UtcNow.AddDays(-100) });
        await db.SaveChangesAsync();
    }

    private static RetentionService Sut(AppDbContext db, int trashedDays = 0, int allDays = 0) =>
        new(db, Options.Create(new DataRetentionOptions
        {
            PurgeTrashedAfterDays = trashedDays,
            PurgeAllAfterDays = allDays
        }), NullLogger<RetentionService>.Instance);

    [Fact]
    public async Task Disabled_retention_purges_nothing()
    {
        using var db = NewDb(nameof(Disabled_retention_purges_nothing));
        await SeedAsync(db);
        (await Sut(db).PurgeAsync()).Should().Be(0);
        (await db.Emails.CountAsync()).Should().Be(3);
    }

    [Fact]
    public async Task Trashed_purge_removes_only_old_trashed_emails()
    {
        using var db = NewDb(nameof(Trashed_purge_removes_only_old_trashed_emails));
        await SeedAsync(db);
        (await Sut(db, trashedDays: 30).PurgeAsync()).Should().Be(1);
        var remaining = await db.Emails.Select(e => e.GmailMessageId).ToListAsync();
        remaining.Should().BeEquivalentTo(new[] { "new-trashed", "old-kept" });
    }

    [Fact]
    public async Task Age_purge_removes_everything_past_the_cutoff()
    {
        using var db = NewDb(nameof(Age_purge_removes_everything_past_the_cutoff));
        await SeedAsync(db);
        (await Sut(db, allDays: 30).PurgeAsync()).Should().Be(2); // both 100-day-old emails
        (await db.Emails.SingleAsync()).GmailMessageId.Should().Be("new-trashed");
    }
}