using System.Security.Claims;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging.Abstractions;
using Nexus.Api.Controllers;
using Nexus.Api.Data;
using Nexus.Api.Models;
using Nexus.Api.Repositories;
using Nexus.Api.Services;
using Xunit;

namespace Nexus.Api.Tests;

public sealed class TaskWorkflowTests
{
    [Fact]
    public async Task CreateAgentTaskAsync_PreservesConfiguredAssigneeAndBacklogState_WhenPlannedChildTask()
    {
        await using var fixture = await TaskWorkflowFixture.CreateAsync();

        var parent = await fixture.TaskService.CreateDashboardTaskAsync(
            "Parent", "Coordination", "iris", "High", "iris", null, CancellationToken.None);

        var child = await fixture.TaskService.CreateAgentTaskAsync(
            "PO spec",
            "Prepare specification",
            "iris",
            "Medium",
            "product-owner",
            "programmer-fast",
            parent.Id,
            startsInProgress: false,
            initialState: null,
            ct: CancellationToken.None);

        Assert.Equal("Backlog", child.State);
        Assert.Equal("product-owner", child.AssignedTo);
        Assert.Equal("programmer-fast", child.ExpectedFrom);
        Assert.True(child.IsAgentTask);
    }

    [Fact]
    public async Task GetDashboardTaskByIdAsync_MapsChildDelegationAndActivity()
    {
        await using var fixture = await TaskWorkflowFixture.CreateAsync();

        var parent = await fixture.TaskService.CreateDashboardTaskAsync(
            "Parent", null, "iris", "High", "iris", null, CancellationToken.None);

        var child = await fixture.TaskService.CreateAgentTaskAsync(
            "Implement",
            "Code changes",
            "iris",
            "High",
            "programmer-fast",
            "programmer-fast",
            parent.Id,
            startsInProgress: false,
            initialState: null,
            ct: CancellationToken.None);

        var dto = await fixture.TaskService.GetDashboardTaskByIdAsync(child.Id, CancellationToken.None);

        Assert.NotNull(dto);
        Assert.True(dto!.HasVisibleDelegation);
        Assert.NotNull(dto.LastActivityMessage);
        Assert.Equal("programmer-fast", dto.AssignedTo);
        Assert.Equal("programmer-fast", dto.ExpectedFrom);
    }

    [Fact]
    public async Task BridgeGetChildTasksAsync_ReturnsMappedActivityAndVisibleDelegation()
    {
        await using var fixture = await TaskWorkflowFixture.CreateAsync();

        var parent = await fixture.TaskService.CreateDashboardTaskAsync(
            "Parent", null, "iris", "High", "iris", null, CancellationToken.None);

        await fixture.TaskBridgeService.CreateChildTaskAsync(
            parent.Id,
            "Review",
            "Review implementation",
            "iris",
            "Medium",
            "reviewer",
            "reviewer",
            startsInProgress: false,
            ct: CancellationToken.None);

        var children = await fixture.TaskBridgeService.GetChildTasksAsync(parent.Id, CancellationToken.None);
        var child = Assert.Single(children);

        Assert.True(child.HasVisibleDelegation);
        Assert.NotNull(child.LastActivityMessage);
        Assert.Equal("reviewer", child.AssignedTo);
    }

    [Fact]
    public async Task GatewayBridgeController_GetBoard_AcceptsProgrammerFastHeader()
    {
        await using var fixture = await TaskWorkflowFixture.CreateAsync();

        var controller = new GatewayBridgeController(
            fixture.TaskBridgeService,
            fixture.AgentService,
            fixture.Configuration,
            NullLogger<GatewayBridgeController>.Instance)
        {
            ControllerContext = new ControllerContext
            {
                HttpContext = TaskWorkflowFixture.CreateHttpContext(headers: new Dictionary<string, string>
                {
                    ["X-Agent-Id"] = "programmer-fast"
                })
            }
        };

        var result = await controller.GetBoard(CancellationToken.None);
        Assert.IsType<OkObjectResult>(result.Result);
    }

    [Fact]
    public async Task GatewayBridgeController_GetBoard_AcceptsServiceKeyWithoutConfiguredNexusSystemAgent()
    {
        await using var fixture = await TaskWorkflowFixture.CreateAsync();

        var controller = new GatewayBridgeController(
            fixture.TaskBridgeService,
            fixture.AgentService,
            fixture.Configuration,
            NullLogger<GatewayBridgeController>.Instance)
        {
            ControllerContext = new ControllerContext
            {
                HttpContext = TaskWorkflowFixture.CreateHttpContext(headers: new Dictionary<string, string>
                {
                    ["X-Nexus-Api-Key"] = "test-service-key"
                })
            }
        };

        var result = await controller.GetBoard(CancellationToken.None);
        Assert.IsType<OkObjectResult>(result.Result);
    }

    [Fact]
    public async Task DashboardController_GetBoard_AcceptsServiceKeyWithoutJwt()
    {
        await using var fixture = await TaskWorkflowFixture.CreateAsync();

        var controller = new DashboardController(
            new FakeDashboardService(),
            fixture.TaskService,
            fixture.ActivityRepository,
            new HttpContextAccessor(),
            fixture.AgentService,
            fixture.Configuration,
            fixture.NotificationService,
            fixture.LiveUpdateService)
        {
            ControllerContext = new ControllerContext
            {
                HttpContext = TaskWorkflowFixture.CreateHttpContext(headers: new Dictionary<string, string>
                {
                    ["X-Nexus-Api-Key"] = "test-service-key"
                })
            }
        };

        var result = await controller.GetBoard(CancellationToken.None);
        Assert.IsType<OkObjectResult>(result.Result);
    }

    [Fact]
    public async Task TasksController_GetBoard_AcceptsProgrammerFastHeader()
    {
        await using var fixture = await TaskWorkflowFixture.CreateAsync();

        var controller = new TasksController(fixture.TaskService, fixture.AgentService, fixture.Configuration)
        {
            ControllerContext = new ControllerContext
            {
                HttpContext = TaskWorkflowFixture.CreateHttpContext(headers: new Dictionary<string, string>
                {
                    ["X-Agent-Id"] = "programmer-fast"
                })
            }
        };

        var result = await controller.GetBoard(CancellationToken.None);

        AssertStatusCode(result, StatusCodes.Status200OK);
    }

    [Fact]
    public async Task TasksController_ResetStale_Anonymous_IsUnauthorized()
    {
        await using var fixture = await TaskWorkflowFixture.CreateAsync();

        var controller = new TasksController(fixture.TaskService, fixture.AgentService, fixture.Configuration)
        {
            ControllerContext = new ControllerContext
            {
                HttpContext = TaskWorkflowFixture.CreateHttpContext()
            }
        };

        var result = await controller.ResetStale(new ResetStaleRequest(2), CancellationToken.None);

        AssertStatusCode(result, StatusCodes.Status401Unauthorized);
    }

    [Fact]
    public async Task TasksController_ResetStale_UnknownAgentHeader_IsForbidden()
    {
        await using var fixture = await TaskWorkflowFixture.CreateAsync();

        var controller = new TasksController(fixture.TaskService, fixture.AgentService, fixture.Configuration)
        {
            ControllerContext = new ControllerContext
            {
                HttpContext = TaskWorkflowFixture.CreateHttpContext(headers: new Dictionary<string, string>
                {
                    ["X-Agent-Id"] = "unknown-agent"
                })
            }
        };

        var result = await controller.ResetStale(new ResetStaleRequest(2), CancellationToken.None);

        AssertStatusCode(result, StatusCodes.Status403Forbidden);
    }

    [Fact]
    public async Task TasksController_ResetStale_OrdinaryJwtUser_IsForbidden()
    {
        await using var fixture = await TaskWorkflowFixture.CreateAsync();

        var controller = new TasksController(fixture.TaskService, fixture.AgentService, fixture.Configuration)
        {
            ControllerContext = new ControllerContext
            {
                HttpContext = TaskWorkflowFixture.CreateHttpContext(user: TaskWorkflowFixture.CreateUser("user-1", "user"))
            }
        };

        var result = await controller.ResetStale(new ResetStaleRequest(2), CancellationToken.None);

        AssertStatusCode(result, StatusCodes.Status403Forbidden);
    }

    [Fact]
    public async Task TasksController_ResetStale_ServiceKey_IsAllowed()
    {
        await using var fixture = await TaskWorkflowFixture.CreateAsync();

        var controller = new TasksController(fixture.TaskService, fixture.AgentService, fixture.Configuration)
        {
            ControllerContext = new ControllerContext
            {
                HttpContext = TaskWorkflowFixture.CreateHttpContext(headers: new Dictionary<string, string>
                {
                    ["X-Nexus-Api-Key"] = "test-service-key"
                })
            }
        };

        var result = await controller.ResetStale(new ResetStaleRequest(2), CancellationToken.None);

        AssertStatusCode(result, StatusCodes.Status200OK);
    }

    [Fact]
    public async Task TasksController_ResetStale_IrisHeader_IsAllowed()
    {
        await using var fixture = await TaskWorkflowFixture.CreateAsync();

        var controller = new TasksController(fixture.TaskService, fixture.AgentService, fixture.Configuration)
        {
            ControllerContext = new ControllerContext
            {
                HttpContext = TaskWorkflowFixture.CreateHttpContext(agentId: "iris")
            }
        };

        var result = await controller.ResetStale(new ResetStaleRequest(2), CancellationToken.None);

        AssertStatusCode(result, StatusCodes.Status200OK);
    }

    [Fact]
    public async Task GatewayBridgeController_GetBoard_OrdinaryJwtUser_IsUnauthorized()
    {
        await using var fixture = await TaskWorkflowFixture.CreateAsync();

        var controller = new GatewayBridgeController(
            fixture.TaskBridgeService,
            fixture.AgentService,
            fixture.Configuration,
            NullLogger<GatewayBridgeController>.Instance)
        {
            ControllerContext = new ControllerContext
            {
                HttpContext = TaskWorkflowFixture.CreateHttpContext(user: TaskWorkflowFixture.CreateUser("user-1", "user"))
            }
        };

        var result = await controller.GetBoard(CancellationToken.None);
        Assert.IsType<UnauthorizedObjectResult>(result.Result);
    }

    [Fact]
    public async Task GatewayBridgeController_GetBoard_AdminJwt_IsAllowed()
    {
        await using var fixture = await TaskWorkflowFixture.CreateAsync();

        var controller = new GatewayBridgeController(
            fixture.TaskBridgeService,
            fixture.AgentService,
            fixture.Configuration,
            NullLogger<GatewayBridgeController>.Instance)
        {
            ControllerContext = new ControllerContext
            {
                HttpContext = TaskWorkflowFixture.CreateHttpContext(user: TaskWorkflowFixture.CreateUser("bao", "admin"))
            }
        };

        var result = await controller.GetBoard(CancellationToken.None);
        Assert.IsType<OkObjectResult>(result.Result);
    }

    [Fact]
    public async Task CreateChildTaskAsync_TransitionsBacklogParent_WhenCallerIsProgrammerFast()
    {
        await using var fixture = await TaskWorkflowFixture.CreateAsync();
        fixture.SetCallerAgent("programmer-fast");

        var parent = await fixture.TaskService.CreateDashboardTaskAsync(
            "Parent", "Coordination", "iris", "High", "iris", null, CancellationToken.None);

        var result = await fixture.TaskBridgeService.CreateChildTaskAsync(
            parent.Id,
            "Implement",
            "Ship the change",
            "programmer-fast",
            "Medium",
            "programmer-fast",
            "programmer-fast",
            startsInProgress: false,
            ct: CancellationToken.None);

        var updatedParent = await fixture.TaskService.GetByIdAsync(parent.Id, CancellationToken.None);

        Assert.Equal(TaskBridgeOutcome.Success, result.Outcome);
        Assert.NotNull(updatedParent);
        Assert.Equal("In progress", updatedParent!.State);
    }

    private static void AssertStatusCode(IResult result, int expectedStatusCode)
    {
        var statusResult = Assert.IsAssignableFrom<IStatusCodeHttpResult>(result);
        Assert.Equal(expectedStatusCode, statusResult.StatusCode);
    }
}

file sealed class TaskWorkflowFixture : IAsyncDisposable
{
    private readonly NexusDbContext _db;

    private TaskWorkflowFixture(
        NexusDbContext db,
        IConfiguration configuration,
        ITaskRepository taskRepository,
        IActivityRepository activityRepository,
        INotificationService notificationService,
        ILiveUpdateService liveUpdateService,
        ITaskService taskService,
        ITaskBridgeService taskBridgeService,
        IAgentService agentService,
        HttpContextAccessor httpContextAccessor)
    {
        _db = db;
        Configuration = configuration;
        TaskRepository = taskRepository;
        ActivityRepository = activityRepository;
        NotificationService = notificationService;
        LiveUpdateService = liveUpdateService;
        TaskService = taskService;
        TaskBridgeService = taskBridgeService;
        AgentService = agentService;
        HttpContextAccessor = httpContextAccessor;
    }

    public IConfiguration Configuration { get; }
    public ITaskRepository TaskRepository { get; }
    public IActivityRepository ActivityRepository { get; }
    public INotificationService NotificationService { get; }
    public ILiveUpdateService LiveUpdateService { get; }
    public ITaskService TaskService { get; }
    public ITaskBridgeService TaskBridgeService { get; }
    public IAgentService AgentService { get; }
    public HttpContextAccessor HttpContextAccessor { get; }

    public static async Task<TaskWorkflowFixture> CreateAsync()
    {
        var options = new DbContextOptionsBuilder<NexusDbContext>()
            .UseInMemoryDatabase(Guid.NewGuid().ToString())
            .Options;

        var db = new NexusDbContext(options);
        await db.Database.EnsureCreatedAsync();

        var configPath = CreateAgentConfigFile();
        var configuration = new ConfigurationBuilder()
            .AddInMemoryCollection(new Dictionary<string, string?>
            {
                ["AgentConfigPath"] = configPath,
                ["NexusApiKey"] = "test-service-key"
            })
            .Build();

        var agentService = new AgentService(configuration, new FakeRuntime());
        var liveUpdateService = new LiveUpdateService();
        var activityRepository = new ActivityRepository(db);
        var taskRepository = new TaskRepository(db);
        var notificationService = new NotificationService(db, liveUpdateService);
        var httpContextAccessor = new HttpContextAccessor { HttpContext = CreateHttpContext(agentId: "iris") };

        var taskService = new TaskService(
            taskRepository,
            activityRepository,
            notificationService,
            agentService,
            httpContextAccessor,
            liveUpdateService);

        var taskBridgeService = new TaskBridgeService(
            taskService,
            agentService,
            activityRepository,
            notificationService,
            liveUpdateService);

        return new TaskWorkflowFixture(
            db,
            configuration,
            taskRepository,
            activityRepository,
            notificationService,
            liveUpdateService,
            taskService,
            taskBridgeService,
            agentService,
            httpContextAccessor);
    }

    public static DefaultHttpContext CreateHttpContext(
        string? agentId = null,
        Dictionary<string, string>? headers = null,
        ClaimsPrincipal? user = null)
    {
        var httpContext = new DefaultHttpContext();
        if (!string.IsNullOrWhiteSpace(agentId))
            httpContext.Request.Headers["X-Agent-Id"] = agentId;

        if (headers is not null)
        {
            foreach (var (key, value) in headers)
                httpContext.Request.Headers[key] = value;
        }

        httpContext.User = user ?? new ClaimsPrincipal(new ClaimsIdentity());
        return httpContext;
    }

    public static ClaimsPrincipal CreateUser(string userId, string role)
    {
        var claims = new[]
        {
            new Claim(ClaimTypes.NameIdentifier, userId),
            new Claim(ClaimTypes.Role, role)
        };

        return new ClaimsPrincipal(new ClaimsIdentity(claims, "TestAuth"));
    }

    public void SetCallerAgent(string agentId)
    {
        HttpContextAccessor.HttpContext = CreateHttpContext(agentId: agentId);
    }

    public async ValueTask DisposeAsync()
    {
        await _db.DisposeAsync();
    }

    private static string CreateAgentConfigFile()
    {
        var path = Path.Combine(Path.GetTempPath(), $"agent-config-{Guid.NewGuid():N}.json");
        File.WriteAllText(path,
            """
            {
              "agents": {
                "defaults": {
                  "workspace": "/workspace/default",
                  "model": {
                    "primary": "deepseek/deepseek-v4-flash"
                  }
                },
                "list": [
                  { "id": "iris", "name": "iris", "model": { "primary": "openai/gpt-5.5" } },
                  { "id": "product-owner", "name": "product-owner", "model": { "primary": "openai/gpt-5.5" } },
                  { "id": "programmer", "name": "programmer", "model": { "primary": "openai/gpt-5.4" } },
                  { "id": "programmer-fast", "name": "programmer-fast", "model": { "primary": "openai/gpt-5.3-codex-spark" } },
                  { "id": "reviewer", "name": "reviewer", "model": { "primary": "openai/gpt-5.5" } }
                ]
              }
            }
            """);

        return path;
    }
}

file sealed class FakeDashboardService : IDashboardService
{
    public Task<DashboardStatus> GetStatusAsync() => Task.FromResult(new DashboardStatus(true, "online", 1, 0));
    public Task<List<DashboardAgentInfo>> GetAgentsAsync() => Task.FromResult(new List<DashboardAgentInfo>());
    public Task<List<FeedEntry>> GetOperationsAsync(int limit, string? agentFilter) => Task.FromResult(new List<FeedEntry>());
    public Task<ChatResponse> SendChatAsync(string agentId, string message) => Task.FromResult(new ChatResponse(true, "", null));
    public Task<List<MessageEntry>> GetMessagesAsync(string? sessionKey, int limit, int offset) => Task.FromResult(new List<MessageEntry>());
    public Task<List<QueueItem>> GetQueueAsync(CancellationToken ct) => Task.FromResult(new List<QueueItem>());
    public Task<QueueDeleteResult> DeleteQueueItemAsync(string id, string? source, CancellationToken ct) => Task.FromResult(new QueueDeleteResult(QueueDeleteOutcome.Ignored));
    public Task<QueuePriorityResult> CycleQueuePriorityAsync(string id, CancellationToken ct) => Task.FromResult(new QueuePriorityResult(QueuePriorityOutcome.Ignored));
    public Task<AgentModelInfo?> GetAgentModelAsync(string agentId) => Task.FromResult<AgentModelInfo?>(null);
    public Task<bool> SetAgentModelAsync(string agentId, string model) => Task.FromResult(false);
    public Task<List<AgentActivityEntry>> GetAgentActivityAsync(string agentId, int limit) => Task.FromResult(new List<AgentActivityEntry>());
    public List<ModelOption> GetAvailableModels() => [];
}