using Xunit;
using FluentAssertions;
using NSubstitute;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using FreeCode.Core.Models;
using FreeCode.Core.Enums;
using CoreTaskStatus = FreeCode.Core.Enums.TaskStatus;

namespace FreeCode.Tests.Unit.Models;

public sealed class BackgroundTaskTests
{
    [Fact]
    public void LocalShellTask_ExposesLocalShellTypeAndCommand()
    {
        var task = new LocalShellTask { TaskId = "task-1", Command = "pwd" };

        task.TaskType.Should().Be(BackgroundTaskType.LocalShell);
        task.Command.Should().Be("pwd");
    }

    [Fact]
    public void LocalShellTask_AllowsProcessAndOutputMutation()
    {
        var startInfo = new ProcessStartInfo("bash", "-lc pwd");
        var task = new LocalShellTask { TaskId = "task-1", Command = "pwd", ProcessStartInfo = startInfo };

        task.Stdout = "output";
        task.Stderr = "error";
        task.ExitCode = 0;

        task.ProcessStartInfo.Should().BeSameAs(startInfo);
        task.Stdout.Should().Be("output");
        task.Stderr.Should().Be("error");
        task.ExitCode.Should().Be(0);
    }

    [Fact]
    public void LocalAgentTask_ExposesLocalAgentTypeAndMetadata()
    {
        var task = new LocalAgentTask
        {
            TaskId = "task-1",
            Prompt = "analyze",
            Model = "gpt-5.4",
            AgentType = "explore",
            WorkingDirectory = "/repo"
        };

        task.TaskType.Should().Be(BackgroundTaskType.LocalAgent);
        task.Prompt.Should().Be("analyze");
        task.Model.Should().Be("gpt-5.4");
        task.AgentType.Should().Be("explore");
        task.WorkingDirectory.Should().Be("/repo");
    }

    [Fact]
    public void LocalAgentTask_StartsWithEmptyMessagesCollection()
    {
        var task = new LocalAgentTask { TaskId = "task-1", Prompt = "analyze" };

        task.Messages.Should().BeEmpty();
    }

    [Fact]
    public void LocalAgentTask_MessagesCollectionIsMutable()
    {
        var task = new LocalAgentTask { TaskId = "task-1", Prompt = "analyze" };
        var message = new Message
        {
            MessageId = "msg-1",
            Role = MessageRole.User,
            Content = new object(),
            Timestamp = new DateTime(2026, 4, 6, 10, 0, 0, DateTimeKind.Utc)
        };

        task.Messages.Add(message);

        task.Messages.Should().ContainSingle().Which.Should().BeSameAs(message);
    }

    [Fact]
    public void RemoteAgentTask_ExposesRemoteAgentTypeAndSessionUrl()
    {
        var task = new RemoteAgentTask { TaskId = "task-1", SessionUrl = "https://example.test/session/1" };

        task.TaskType.Should().Be(BackgroundTaskType.RemoteAgent);
        task.SessionUrl.Should().Be("https://example.test/session/1");
    }

    [Fact]
    public void RemoteAgentTask_UsesShadowedStringStatusAlongsideBaseEnumStatus()
    {
        var task = new RemoteAgentTask { TaskId = "task-1", SessionUrl = "https://example.test/session/1" };

        task.Status = "waiting";
        ((BackgroundTask)task).Status = CoreTaskStatus.Running;

        task.Status.Should().Be("waiting");
        ((BackgroundTask)task).Status.Should().Be(CoreTaskStatus.Running);
    }

    [Fact]
    public void InProcessTeammateTask_ExposesTeammateTypeAndProperties()
    {
        var task = new InProcessTeammateTask
        {
            TaskId = "task-1",
            AgentName = "Ada",
            AgentType = "reviewer",
            Color = "blue",
            WorkingDirectory = "/repo"
        };

        task.TaskType.Should().Be(BackgroundTaskType.InProcessTeammate);
        task.AgentName.Should().Be("Ada");
        task.AgentType.Should().Be("reviewer");
        task.Color.Should().Be("blue");
        task.WorkingDirectory.Should().Be("/repo");
    }

    [Fact]
    public void LocalWorkflowTask_ExposesWorkflowTypeAndSteps()
    {
        var steps = new List<object> { "step-1", 2 };
        var task = new LocalWorkflowTask { TaskId = "task-1", WorkflowName = "Build", Steps = steps };

        task.TaskType.Should().Be(BackgroundTaskType.LocalWorkflow);
        task.WorkflowName.Should().Be("Build");
        task.Steps.Should().BeSameAs(steps);
        task.CurrentStepIndex.Should().Be(0);
    }

    [Fact]
    public void LocalWorkflowTask_CurrentStepIndexIsMutable()
    {
        var task = new LocalWorkflowTask { TaskId = "task-1", WorkflowName = "Build", Steps = [] };

        task.CurrentStepIndex = 2;

        task.CurrentStepIndex.Should().Be(2);
    }

    [Fact]
    public void MonitorMcpTask_ExposesMonitorTypeAndReconnectAttempt()
    {
        var task = new MonitorMcpTask { TaskId = "task-1", ServerName = "filesystem" };

        task.TaskType.Should().Be(BackgroundTaskType.MonitorMcp);
        task.ServerName.Should().Be("filesystem");
        task.ReconnectAttempt.Should().Be(0);
    }

    [Fact]
    public void DreamTask_ExposesDreamTypeAndReason()
    {
        var task = new DreamTask { TaskId = "task-1", TriggerReason = "idle-compaction" };

        task.TaskType.Should().Be(BackgroundTaskType.Dream);
        task.TriggerReason.Should().Be("idle-compaction");
    }

    [Fact]
    public void BackgroundTask_CommonStateIsMutable()
    {
        var task = new LocalShellTask { TaskId = "task-1", Command = "pwd" };
        var startedAt = new DateTime(2026, 4, 6, 10, 0, 0, DateTimeKind.Utc);
        var completedAt = startedAt.AddMinutes(1);

        task.Status = CoreTaskStatus.Completed;
        task.StartedAt = startedAt;
        task.CompletedAt = completedAt;
        task.ErrorMessage = "none";
        task.IsBackgrounded = false;

        task.Status.Should().Be(CoreTaskStatus.Completed);
        task.StartedAt.Should().Be(startedAt);
        task.CompletedAt.Should().Be(completedAt);
        task.ErrorMessage.Should().Be("none");
        task.IsBackgrounded.Should().BeFalse();
    }

    [Theory]
    [MemberData(nameof(AllTasks))]
    public void BackgroundTask_DefaultStatusIsPending(BackgroundTask task)
    {
        task.Status.Should().Be(CoreTaskStatus.Pending);
    }

    [Theory]
    [MemberData(nameof(AllTasks))]
    public void BackgroundTask_DefaultIsBackgroundedIsTrue(BackgroundTask task)
    {
        task.IsBackgrounded.Should().BeTrue();
    }

    [Theory]
    [MemberData(nameof(AllTasks))]
    public void BackgroundTask_DefaultStartedAtIsNull(BackgroundTask task)
    {
        task.StartedAt.Should().BeNull();
    }

    [Theory]
    [MemberData(nameof(AllTasks))]
    public void BackgroundTask_DefaultCompletedAtIsNull(BackgroundTask task)
    {
        task.CompletedAt.Should().BeNull();
    }

    [Theory]
    [MemberData(nameof(AllTasks))]
    public void BackgroundTask_DefaultErrorMessageIsNull(BackgroundTask task)
    {
        task.ErrorMessage.Should().BeNull();
    }

    [Theory]
    [MemberData(nameof(AllTasks))]
    public void BackgroundTask_PreservesTaskId(BackgroundTask task)
    {
        task.TaskId.Should().NotBeNullOrEmpty();
    }

    [Theory]
    [MemberData(nameof(AllTasks))]
    public void BackgroundTask_ExposesExpectedTaskType(BackgroundTask task)
    {
        task.TaskType.Should().BeOneOf(
            BackgroundTaskType.LocalShell,
            BackgroundTaskType.LocalAgent,
            BackgroundTaskType.RemoteAgent,
            BackgroundTaskType.InProcessTeammate,
            BackgroundTaskType.LocalWorkflow,
            BackgroundTaskType.MonitorMcp,
            BackgroundTaskType.Dream);
    }

    public static IEnumerable<object[]> AllTasks()
    {
        yield return [new LocalShellTask { TaskId = "shell-1", Command = "pwd" }];
        yield return [new LocalAgentTask { TaskId = "agent-1", Prompt = "analyze" }];
        yield return [new RemoteAgentTask { TaskId = "remote-1", SessionUrl = "https://example.test/session/1" }];
        yield return [new InProcessTeammateTask { TaskId = "mate-1", AgentName = "Ada", WorkingDirectory = "/repo" }];
        yield return [new LocalWorkflowTask { TaskId = "workflow-1", WorkflowName = "Build", Steps = [] }];
        yield return [new MonitorMcpTask { TaskId = "mcp-1", ServerName = "filesystem" }];
        yield return [new DreamTask { TaskId = "dream-1", TriggerReason = "idle-compaction" }];
    }
}