using Distribution.Features.Region;
using Distribution.Infra.Authorization;
using Distribution.Infra.UoW;
using Distribution.Models;
using Moq;
using Xunit;

namespace Distribution.Tests.Services;

public class RegionServiceTests
{
    private readonly Mock<IRegionRepository> _repo = new();
    private readonly Mock<IUnitOfWork> _uow = new();
    private readonly Mock<ICurrentUserService> _currentUser = new();
    private readonly Mock<IScopeAccessService> _scopeAccess = new();
    private readonly RegionService _sut;

    public RegionServiceTests()
    {
        _currentUser.Setup(u => u.RoleLevel).Returns(60);
        _repo.Setup(r => r.GetAllCodesAsync()).ReturnsAsync([]);
        _sut = new RegionService(_repo.Object, _uow.Object, _currentUser.Object, _scopeAccess.Object);
    }

    private static Region ActiveRegion(string name = "North") =>
        new() { Id = Guid.NewGuid(), Name = name, IsActive = true };

    private static Region InactiveRegion() =>
        new() { Id = Guid.NewGuid(), Name = "Old", IsActive = false };

    // GetAllAsync

    [Fact]
    public async Task GetAllAsync_ReturnsOnlyActiveRegions()
    {
        _repo.Setup(r => r.GetAllAsync()).ReturnsAsync([ActiveRegion(), InactiveRegion()]);

        var result = await _sut.GetAllAsync();

        Assert.Single(result);
        Assert.True(result[0].IsActive);
    }

    [Fact]
    public async Task GetAllAsync_ReturnsEmpty_WhenNoneActive()
    {
        _repo.Setup(r => r.GetAllAsync()).ReturnsAsync([InactiveRegion()]);

        var result = await _sut.GetAllAsync();

        Assert.Empty(result);
    }

    // GetByIdAsync

    [Fact]
    public async Task GetByIdAsync_ReturnsNull_WhenNotFound()
    {
        _repo.Setup(r => r.GetByIdAsync(It.IsAny<Guid>())).ReturnsAsync((Region?)null);

        var result = await _sut.GetByIdAsync(Guid.NewGuid());

        Assert.Null(result);
    }

    [Fact]
    public async Task GetByIdAsync_ReturnsNull_WhenInactive()
    {
        _repo.Setup(r => r.GetByIdAsync(It.IsAny<Guid>())).ReturnsAsync(InactiveRegion());

        var result = await _sut.GetByIdAsync(Guid.NewGuid());

        Assert.Null(result);
    }

    [Fact]
    public async Task GetByIdAsync_ReturnsResponse_WhenActiveRegionFound()
    {
        var region = ActiveRegion("South");
        _repo.Setup(r => r.GetByIdAsync(region.Id)).ReturnsAsync(region);

        var result = await _sut.GetByIdAsync(region.Id);

        Assert.NotNull(result);
        Assert.Equal("South", result.Name);
        Assert.Equal(region.Id, result.Id);
    }

    // CreateAsync

    [Fact]
    public async Task CreateAsync_AddsRegion_AndCommits()
    {
        var request = new CreateRegionRequest("East");

        var result = await _sut.CreateAsync(request);

        _uow.Verify(u => u.BeginAsync(default), Times.Once);
        _repo.Verify(r => r.AddAsync(It.Is<Region>(x => x.Name == "East")), Times.Once);
        _uow.Verify(u => u.CommitAsync(default), Times.Once);
        Assert.Equal("East", result.Name);
    }

    [Fact]
    public async Task CreateAsync_Rollbacks_WhenAddThrows()
    {
        _repo.Setup(r => r.AddAsync(It.IsAny<Region>())).ThrowsAsync(new Exception("db error"));

        await Assert.ThrowsAsync<Exception>(() => _sut.CreateAsync(new CreateRegionRequest("X")));

        _uow.Verify(u => u.RollbackAsync(default), Times.Once);
        _uow.Verify(u => u.CommitAsync(default), Times.Never);
    }

    // UpdateAsync

    [Fact]
    public async Task UpdateAsync_ReturnsNull_WhenNotFound()
    {
        _repo.Setup(r => r.GetByIdAsync(It.IsAny<Guid>())).ReturnsAsync((Region?)null);

        var result = await _sut.UpdateAsync(Guid.NewGuid(), new UpdateRegionRequest("New"));

        Assert.Null(result);
        _uow.Verify(u => u.BeginAsync(default), Times.Never);
    }

    [Fact]
    public async Task UpdateAsync_ReturnsNull_WhenInactive()
    {
        _repo.Setup(r => r.GetByIdAsync(It.IsAny<Guid>())).ReturnsAsync(InactiveRegion());

        var result = await _sut.UpdateAsync(Guid.NewGuid(), new UpdateRegionRequest("New"));

        Assert.Null(result);
    }

    [Fact]
    public async Task UpdateAsync_UpdatesName_AndCommits()
    {
        var region = ActiveRegion("Old Name");
        _repo.Setup(r => r.GetByIdAsync(region.Id)).ReturnsAsync(region);

        var result = await _sut.UpdateAsync(region.Id, new UpdateRegionRequest("New Name"));

        Assert.NotNull(result);
        Assert.Equal("New Name", result.Name);
        _uow.Verify(u => u.BeginAsync(default), Times.Once);
        _uow.Verify(u => u.CommitAsync(default), Times.Once);
    }

    // Region code

    [Fact]
    public async Task CreateAsync_GeneratesFirstCode_WhenNoRegionsExist()
    {
        _repo.Setup(r => r.GetAllCodesAsync()).ReturnsAsync([]);

        var result = await _sut.CreateAsync(new CreateRegionRequest("North"));

        Assert.Equal("REG-0001", result.Code);
    }

    [Fact]
    public async Task CreateAsync_GeneratesNextCode_FromHighestExisting_IgnoringNonMatching()
    {
        _repo.Setup(r => r.GetAllCodesAsync()).ReturnsAsync(["REG-0002", "REG-0009", "CUSTOM", "REG-abc", ""]);

        var result = await _sut.CreateAsync(new CreateRegionRequest("North"));

        Assert.Equal("REG-0010", result.Code);
    }

    [Fact]
    public async Task CreateAsync_StoresProvidedCode_AsEntered()
    {
        var result = await _sut.CreateAsync(new CreateRegionRequest("North", " nth-1 "));

        Assert.Equal("nth-1", result.Code);
        _repo.Verify(r => r.GetAllCodesAsync(), Times.Never);
    }

    [Fact]
    public async Task CreateAsync_Throws_WhenProvidedCodeInUse()
    {
        _repo.Setup(r => r.CodeExistsAsync("NTH-1", null)).ReturnsAsync(true);

        await Assert.ThrowsAsync<InvalidOperationException>(() =>
            _sut.CreateAsync(new CreateRegionRequest("North", "NTH-1")));

        _uow.Verify(u => u.CommitAsync(default), Times.Never);
    }

    [Fact]
    public async Task GetNextCodeAsync_ReturnsSuggestion()
    {
        _repo.Setup(r => r.GetAllCodesAsync()).ReturnsAsync(["REG-0003"]);

        var result = await _sut.GetNextCodeAsync();

        Assert.Equal("REG-0004", result.Code);
    }

    [Fact]
    public async Task UpdateAsync_ChangesCode_StoredAsEntered()
    {
        var region = ActiveRegion();
        region.Code = "REG-0001";
        _repo.Setup(r => r.GetByIdAsync(region.Id)).ReturnsAsync(region);
        _repo.Setup(r => r.CodeExistsAsync("north-1", region.Id)).ReturnsAsync(false);

        var result = await _sut.UpdateAsync(region.Id, new UpdateRegionRequest("North", " north-1 "));

        Assert.Equal("north-1", result!.Code);
        _uow.Verify(u => u.CommitAsync(default), Times.Once);
    }

    [Fact]
    public async Task UpdateAsync_KeepsCode_WhenCodeBlank()
    {
        var region = ActiveRegion();
        region.Code = "REG-0001";
        _repo.Setup(r => r.GetByIdAsync(region.Id)).ReturnsAsync(region);

        var result = await _sut.UpdateAsync(region.Id, new UpdateRegionRequest("North", "  "));

        Assert.Equal("REG-0001", result!.Code);
        _repo.Verify(r => r.CodeExistsAsync(It.IsAny<string>(), It.IsAny<Guid?>()), Times.Never);
    }

    [Fact]
    public async Task UpdateAsync_Throws_WhenCodeUsedByAnotherRegion()
    {
        var region = ActiveRegion();
        region.Code = "REG-0001";
        _repo.Setup(r => r.GetByIdAsync(region.Id)).ReturnsAsync(region);
        _repo.Setup(r => r.CodeExistsAsync("REG-0002", region.Id)).ReturnsAsync(true);

        await Assert.ThrowsAsync<InvalidOperationException>(() =>
            _sut.UpdateAsync(region.Id, new UpdateRegionRequest("North", "REG-0002")));

        _uow.Verify(u => u.CommitAsync(default), Times.Never);
    }

    [Fact]
    public async Task UpdateAsync_AllowsResubmittingOwnCode()
    {
        var region = ActiveRegion();
        region.Code = "REG-0001";
        _repo.Setup(r => r.GetByIdAsync(region.Id)).ReturnsAsync(region);

        var result = await _sut.UpdateAsync(region.Id, new UpdateRegionRequest("North", "REG-0001"));

        Assert.Equal("REG-0001", result!.Code);
    }

    [Fact]
    public async Task GetByIdAsync_ReturnsCode()
    {
        var region = ActiveRegion();
        region.Code = "REG-0007";
        _repo.Setup(r => r.GetByIdAsync(region.Id)).ReturnsAsync(region);

        var result = await _sut.GetByIdAsync(region.Id);

        Assert.Equal("REG-0007", result!.Code);
    }

    // DeleteAsync

    [Fact]
    public async Task DeleteAsync_ReturnsFalse_WhenNotFound()
    {
        _repo.Setup(r => r.GetByIdAsync(It.IsAny<Guid>())).ReturnsAsync((Region?)null);

        var result = await _sut.DeleteAsync(Guid.NewGuid());

        Assert.False(result);
        _uow.Verify(u => u.BeginAsync(default), Times.Never);
    }

    [Fact]
    public async Task DeleteAsync_ReturnsFalse_WhenInactive()
    {
        _repo.Setup(r => r.GetByIdAsync(It.IsAny<Guid>())).ReturnsAsync(InactiveRegion());

        var result = await _sut.DeleteAsync(Guid.NewGuid());

        Assert.False(result);
    }

    [Fact]
    public async Task DeleteAsync_CallsRemove_AndCommits()
    {
        var region = ActiveRegion();
        _repo.Setup(r => r.GetByIdAsync(region.Id)).ReturnsAsync(region);

        var result = await _sut.DeleteAsync(region.Id);

        Assert.True(result);
        _repo.Verify(r => r.Remove(region), Times.Once);
        _uow.Verify(u => u.CommitAsync(default), Times.Once);
    }

    [Fact]
    public async Task DeleteAsync_Rollbacks_WhenRemoveThrows()
    {
        var region = ActiveRegion();
        _repo.Setup(r => r.GetByIdAsync(region.Id)).ReturnsAsync(region);
        _repo.Setup(r => r.Remove(It.IsAny<Region>())).Throws(new Exception("db error"));

        await Assert.ThrowsAsync<Exception>(() => _sut.DeleteAsync(region.Id));

        _uow.Verify(u => u.RollbackAsync(default), Times.Once);
    }
}