using BuildingBlock.Identity.Contracts.Conventions;
using BuildingBlock.Identity.Contracts.Requests;
using BuildingBlock.Identity.Contracts.Responses;
using Thalos.Service.Application.Oidc;
using Thalos.Service.Application.Sessions;
using Thalos.Service.Application.UseCases;
using Thalos.Service.Identity.Abstractions.Contracts;
using ExchangeRequest = BuildingBlock.Identity.Contracts.Requests.ExchangeIdentityProviderTokenRequest;
using ExchangeResponse = BuildingBlock.Identity.Contracts.Responses.ExchangeIdentityProviderTokenResponse;
using IdentityIssueRequest = BuildingBlock.Identity.Contracts.Requests.IssueIdentityTokenRequest;
using IdentityIssueResponse = BuildingBlock.Identity.Contracts.Responses.IssueIdentityTokenResponse;

namespace Thalos.Service.Application.UnitTests;

public class StartIdentitySessionUseCaseTests
{
    [Fact]
    public async Task HandleAsync_WhenCalled_IssuesTokenAndRefreshToken()
    {
        var issueUseCase = new FakeIssueUseCase();
        var useCase = new StartIdentitySessionUseCase(
            issueUseCase,
            new FakeExchangeService(),
            new FakeSessionTokenCodec());

        var response = await useCase.HandleAsync(new StartIdentitySessionRequest("user-1", "tenant-1", IdentityAuthProvider.InternalJwt));

        Assert.Equal("token-abc", response.AccessToken);
        Assert.Equal(1800, response.ExpiresInSeconds);
        Assert.Equal("user-1", response.SubjectId);
        Assert.Equal("tenant-1", response.TenantId);
        Assert.Equal("refresh-user-1-tenant-1", response.RefreshToken);
        Assert.NotNull(issueUseCase.LastRequest);
        Assert.Equal("user-1", issueUseCase.LastRequest!.SubjectId);
    }

    [Fact]
    public async Task HandleAsync_WhenGoogleProviderAndExchangeSucceeds_UsesExchangedSubject()
    {
        var issueUseCase = new FakeIssueUseCase();
        var exchangeService = new FakeExchangeService
        {
            NextResponse = new ExchangeResponse(
                "google-sub-123",
                "tenant-1",
                IdentityAuthProvider.Google,
                true)
        };

        var useCase = new StartIdentitySessionUseCase(
            issueUseCase,
            exchangeService,
            new FakeSessionTokenCodec());

        var response = await useCase.HandleAsync(new StartIdentitySessionRequest(
            string.Empty,
            "tenant-1",
            IdentityAuthProvider.Google,
            "google-id-token",
            "corr-1"));

        Assert.Equal("token-abc", response.AccessToken);
        Assert.Equal("google-sub-123", response.SubjectId);
        Assert.Equal(IdentityAuthProvider.Google, response.Provider);
        Assert.NotNull(issueUseCase.LastRequest);
        Assert.Equal("google-sub-123", issueUseCase.LastRequest!.SubjectId);
        Assert.Equal("google-id-token", issueUseCase.LastRequest.ExternalToken);
    }

    [Fact]
    public async Task HandleAsync_WhenGoogleExchangeFails_ReturnsFailedSession()
    {
        var issueUseCase = new FakeIssueUseCase();
        var exchangeService = new FakeExchangeService
        {
            NextResponse = new ExchangeResponse(
                string.Empty,
                "tenant-1",
                IdentityAuthProvider.Google,
                false)
        };
        var useCase = new StartIdentitySessionUseCase(
            issueUseCase,
            exchangeService,
            new FakeSessionTokenCodec());

        var response = await useCase.HandleAsync(new StartIdentitySessionRequest(
            string.Empty,
            "tenant-1",
            IdentityAuthProvider.Google,
            "invalid-token",
            "corr-2"));

        Assert.Equal(string.Empty, response.AccessToken);
        Assert.Equal(string.Empty, response.RefreshToken);
        Assert.Equal(0, response.ExpiresInSeconds);
        Assert.Null(issueUseCase.LastRequest);
    }

    private sealed class FakeIssueUseCase : IIssueIdentityTokenUseCase
    {
        public IdentityIssueRequest? LastRequest { get; private set; }

        public Task<IdentityIssueResponse> HandleAsync(IdentityIssueRequest request)
        {
            LastRequest = request;
            return Task.FromResult(new IdentityIssueResponse("token-abc", 1800));
        }
    }

    private sealed class FakeExchangeService : IIdentityProviderTokenExchangeService
    {
        public ExchangeResponse NextResponse { get; set; } = new(
            string.Empty,
            string.Empty,
            IdentityAuthProvider.Google,
            false);

        public Task<ExchangeResponse> ExchangeAsync(ExchangeRequest request, CancellationToken cancellationToken = default)
        {
            return Task.FromResult(NextResponse);
        }
    }

    private sealed class FakeSessionTokenCodec : IIdentitySessionTokenCodec
    {
        public string Encode(IdentitySessionDescriptor descriptor)
        {
            return $"refresh-{descriptor.SubjectId}-{descriptor.TenantId}";
        }

        public bool TryDecode(string token, out IdentitySessionDescriptor descriptor)
        {
            descriptor = new IdentitySessionDescriptor(string.Empty, string.Empty, IdentityAuthProvider.InternalJwt, DateTimeOffset.UtcNow);
            return false;
        }
    }
}