using FluentAssertions;
using Microsoft.Extensions.Time.Testing;
using NSubstitute;
using NSubstitute.ExceptionExtensions;
using SIGCM2.Application.Abstractions.Persistence;
using SIGCM2.Application.Audit;
using SIGCM2.Application.Pricing.ChargeableChars.SchedulePrice;
using SIGCM2.Domain.Pricing.ChargeableChars;
using SIGCM2.Domain.Pricing.Exceptions;

namespace SIGCM2.Application.Tests.Pricing.ChargeableChars;

/// <summary>
/// PRC-001 — SchedulePriceChangeCommandHandler tests.
/// Covers: happy path, forward-only validation, audit emit, audit fail → rollback.
/// </summary>
public class SchedulePriceChangeHandlerTests
{
    private readonly FakeTimeProvider _time = new(new DateTimeOffset(2026, 4, 20, 12, 0, 0, TimeSpan.Zero));
    private readonly IChargeableCharConfigRepository _repo = Substitute.For<IChargeableCharConfigRepository>();
    private readonly IAuditLogger _audit = Substitute.For<IAuditLogger>();
    private readonly SchedulePriceChangeCommandHandler _handler;

    private static readonly DateOnly Today = new(2026, 4, 20);
    private static readonly DateOnly NextMonth = new(2026, 5, 1);

    private static ChargeableCharConfig ExistingConfig(DateOnly validFrom) =>
        ChargeableCharConfig.Rehydrate(1L, null, "$", ChargeableCharCategories.Currency, 1.0m, validFrom, null, true);

    public SchedulePriceChangeHandlerTests()
    {
        _repo.GetByIdAsync(1L, Arg.Any<CancellationToken>())
            .Returns(ExistingConfig(Today));

        _repo.InsertWithCloseAsync(
                Arg.Any<long?>(), Arg.Any<string>(), Arg.Any<string>(),
                Arg.Any<decimal>(), Arg.Any<DateOnly>(), Arg.Any<CancellationToken>())
            .Returns(99L);

        _handler = new SchedulePriceChangeCommandHandler(_repo, _audit, _time);
    }

    private static SchedulePriceChangeCommand ValidCmd() => new(
        Id: 1L,
        PricePerUnit: 2.5m,
        ValidFrom: NextMonth);

    // ── Happy path ──────────────────────────────────────────────────────────────

    [Fact]
    public async Task Handle_HappyPath_ReturnsScheduleResponse()
    {
        var result = await _handler.Handle(ValidCmd());

        result.Should().NotBeNull();
        result.NewId.Should().Be(99L);
        result.PreviousValidFrom.Should().Be(Today);
        result.NewValidFrom.Should().Be(NextMonth);
    }

    [Fact]
    public async Task Handle_HappyPath_CallsInsertWithCloseAsync()
    {
        await _handler.Handle(ValidCmd());

        await _repo.Received(1).InsertWithCloseAsync(
            null, "$", ChargeableCharCategories.Currency, 2.5m, NextMonth, Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task Handle_HappyPath_EmitsAuditPriceChange()
    {
        await _handler.Handle(ValidCmd());

        await _audit.Received(1).LogAsync(
            action: "tasacion.chargeable_char.price_change",
            targetType: "ChargeableCharConfig",
            targetId: "99",
            metadata: Arg.Any<object?>(),
            ct: Arg.Any<CancellationToken>());
    }

    // ── Not found ───────────────────────────────────────────────────────────────

    [Fact]
    public async Task Handle_ConfigNotFound_ThrowsKeyNotFoundException()
    {
        _repo.GetByIdAsync(99L, Arg.Any<CancellationToken>())
            .Returns((ChargeableCharConfig?)null);

        var act = async () => await _handler.Handle(ValidCmd() with { Id = 99L });

        await act.Should().ThrowAsync<KeyNotFoundException>();
    }

    // ── Forward-only enforcement ─────────────────────────────────────────────────

    [Fact]
    public async Task Handle_ValidFromNotGreaterThanCurrent_ThrowsForwardOnlyException()
    {
        // The existing config has ValidFrom = Today; scheduling for Today is not > Today
        var cmd = ValidCmd() with { ValidFrom = Today };

        var act = async () => await _handler.Handle(cmd);

        await act.Should().ThrowAsync<ChargeableCharConfigForwardOnlyException>();
    }

    // ── Audit fail → rollback ───────────────────────────────────────────────────

    [Fact]
    public async Task Handle_AuditThrows_ExceptionPropagates()
    {
        _audit.LogAsync(
                Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(),
                Arg.Any<object?>(), Arg.Any<CancellationToken>())
            .ThrowsAsync(new InvalidOperationException("Audit error"));

        var act = async () => await _handler.Handle(ValidCmd());

        await act.Should().ThrowAsync<InvalidOperationException>()
            .WithMessage("Audit error");
    }
}