using System.Collections.ObjectModel;
using Avalonia.Threading;
using ClaudeDo.Data.Models;
using ClaudeDo.Data.Repositories;
using CommunityToolkit.Mvvm.ComponentModel;
using Microsoft.AspNetCore.SignalR;
using Microsoft.AspNetCore.SignalR.Client;
using Microsoft.Extensions.DependencyInjection;

namespace ClaudeDo.Ui.Services;

public record ActiveTask(string Slot, string TaskId, DateTime StartedAt);
public sealed record WorkerLogEntry(string Message, WorkerLogLevel Level, DateTime TimestampUtc);

sealed class IndefiniteRetryPolicy : IRetryPolicy
{
    private static readonly TimeSpan[] _delays =
    [
        TimeSpan.Zero,
        TimeSpan.FromSeconds(2),
        TimeSpan.FromSeconds(5),
        TimeSpan.FromSeconds(10),
        TimeSpan.FromSeconds(30),
    ];

    public TimeSpan? NextRetryDelay(RetryContext retryContext) =>
        _delays[Math.Min(retryContext.PreviousRetryCount, _delays.Length - 1)];
}

public partial class WorkerClient : ObservableObject, IAsyncDisposable, IWorkerClient
{
    private readonly HubConnection _hub;
    private CancellationTokenSource? _startCts;
    private Task _retryLoopTask = Task.CompletedTask;
    private readonly object _startLock = new();

    [ObservableProperty]
    private bool _isConnected;

    [ObservableProperty]
    private bool _isReconnecting;

    public ObservableCollection<ActiveTask> ActiveTasks { get; } = new();

    public event Action<string, string, DateTime>? TaskStartedEvent;
    public event Action<string, string, string, DateTime>? TaskFinishedEvent;
    public event Action<string, string>? TaskMessageEvent;
    public event Action<string>? TaskUpdatedEvent;
    public event Action? ConnectionRestoredEvent;
    public event Action<string>? WorktreeUpdatedEvent;
    public event Action<string>? ListUpdatedEvent;
    public event Action<WorkerLogEntry>? WorkerLogReceivedEvent;

    public event Action? PrepStartedEvent;
    public event Action<string>? PrepLineEvent;
    public event Action<bool>? PrepFinishedEvent;

    public event Action<string, string>? PlanningMergeStartedEvent;
    public event Action<string, string>? PlanningSubtaskMergedEvent;
    public event Action<string, string, IReadOnlyList<string>>? PlanningMergeConflictEvent;
    public event Action<string>? PlanningMergeAbortedEvent;
    public event Action<string>? PlanningCompletedEvent;

    public event Action<PrimeFiredEvent>? PrimeFired;

    public string? LastMergeAllTarget { get; private set; }

    public WorkerClient(string signalRUrl)
    {
        _hub = new HubConnectionBuilder()
            .WithUrl(signalRUrl)
            .WithAutomaticReconnect(new IndefiniteRetryPolicy())
            .AddJsonProtocol(options =>
            {
                options.PayloadSerializerOptions.Converters.Add(new System.Text.Json.Serialization.JsonStringEnumConverter());
            })
            .Build();

        _hub.Reconnected += async _ =>
        {
            Dispatcher.UIThread.Post(() => { IsConnected = true; IsReconnecting = false; });
            await SeedActiveTasksAsync();
            Dispatcher.UIThread.Post(() => ConnectionRestoredEvent?.Invoke());
        };

        _hub.Reconnecting += _ =>
        {
            Dispatcher.UIThread.Post(() => { IsConnected = false; IsReconnecting = true; });
            return Task.CompletedTask;
        };

        _hub.Closed += _ =>
        {
            Dispatcher.UIThread.Post(() =>
            {
                IsConnected = false;
                IsReconnecting = false;
                ActiveTasks.Clear();
            });
            return Task.CompletedTask;
        };

        _hub.On<string, string, DateTime>("TaskStarted", (slot, taskId, startedAt) =>
        {
            Dispatcher.UIThread.Post(() =>
            {
                ActiveTasks.Add(new ActiveTask(slot, taskId, startedAt));
                TaskStartedEvent?.Invoke(slot, taskId, startedAt);
            });
        });

        _hub.On<string, string, string, DateTime>("TaskFinished", (slot, taskId, status, finishedAt) =>
        {
            Dispatcher.UIThread.Post(() =>
            {
                var existing = ActiveTasks.FirstOrDefault(t => t.TaskId == taskId);
                if (existing is not null)
                    ActiveTasks.Remove(existing);
                TaskFinishedEvent?.Invoke(slot, taskId, status, finishedAt);
            });
        });

        _hub.On<string, string>("TaskMessage", (taskId, line) =>
        {
            Dispatcher.UIThread.Post(() => TaskMessageEvent?.Invoke(taskId, line));
        });

        _hub.On<string>("TaskUpdated", taskId =>
        {
            Dispatcher.UIThread.Post(() => TaskUpdatedEvent?.Invoke(taskId));
        });

        _hub.On<string>("WorktreeUpdated", taskId =>
        {
            Dispatcher.UIThread.Post(() => WorktreeUpdatedEvent?.Invoke(taskId));
        });

        _hub.On<string>("ListUpdated", listId =>
        {
            Dispatcher.UIThread.Post(() => ListUpdatedEvent?.Invoke(listId));
        });

        _hub.On<string, WorkerLogLevel, DateTime>("WorkerLog", (message, level, timestampUtc) =>
        {
            Dispatcher.UIThread.Post(() =>
                WorkerLogReceivedEvent?.Invoke(new WorkerLogEntry(message, level, timestampUtc)));
        });

        _hub.On<string, string>("PlanningMergeStarted", (planningTaskId, targetBranch) =>
        {
            Dispatcher.UIThread.Post(() => PlanningMergeStartedEvent?.Invoke(planningTaskId, targetBranch));
        });

        _hub.On<string, string>("PlanningSubtaskMerged", (planningTaskId, subtaskId) =>
        {
            Dispatcher.UIThread.Post(() => PlanningSubtaskMergedEvent?.Invoke(planningTaskId, subtaskId));
        });

        _hub.On<string, string, IReadOnlyList<string>>("PlanningMergeConflict", (planningTaskId, subtaskId, conflictedFiles) =>
        {
            Dispatcher.UIThread.Post(() => PlanningMergeConflictEvent?.Invoke(planningTaskId, subtaskId, conflictedFiles));
        });

        _hub.On<string>("PlanningMergeAborted", planningTaskId =>
        {
            Dispatcher.UIThread.Post(() => PlanningMergeAbortedEvent?.Invoke(planningTaskId));
        });

        _hub.On<string>("PlanningCompleted", planningTaskId =>
        {
            Dispatcher.UIThread.Post(() => PlanningCompletedEvent?.Invoke(planningTaskId));
        });

        _hub.On<Guid, bool, string, DateTimeOffset>("PrimeFired", (id, ok, msg, when) =>
        {
            Dispatcher.UIThread.Post(() => PrimeFired?.Invoke(new PrimeFiredEvent(id, ok, msg, when)));
        });

        _hub.On("PrepStarted", () => Dispatcher.UIThread.Post(() => PrepStartedEvent?.Invoke()));
        _hub.On<string>("PrepLine", line => Dispatcher.UIThread.Post(() => PrepLineEvent?.Invoke(line)));
        _hub.On<bool>("PrepFinished", ok => Dispatcher.UIThread.Post(() => PrepFinishedEvent?.Invoke(ok)));
    }

    public Task StartAsync()
    {
        lock (_startLock)
        {
            if (!_retryLoopTask.IsCompleted)
                return Task.CompletedTask;

            var old = _startCts;
            _startCts = new CancellationTokenSource();
            old?.Cancel();
            old?.Dispose();

            _retryLoopTask = ConnectWithRetryAsync(_startCts.Token);
        }
        return Task.CompletedTask;
    }

    private async Task ConnectWithRetryAsync(CancellationToken ct)
    {
        var delays = new[] { 0, 2, 5, 10, 30 };
        int attempt = 0;
        Dispatcher.UIThread.Post(() => IsReconnecting = true);
        while (!ct.IsCancellationRequested)
        {
            try
            {
                await _hub.StartAsync(ct);
                Dispatcher.UIThread.Post(() => { IsConnected = true; IsReconnecting = false; });
                await SeedActiveTasksAsync();
                Dispatcher.UIThread.Post(() => ConnectionRestoredEvent?.Invoke());
                return;
            }
            catch (OperationCanceledException)
            {
                return;
            }
            catch
            {
                var delay = delays[Math.Min(attempt++, delays.Length - 1)];
                try { await Task.Delay(TimeSpan.FromSeconds(delay), ct); }
                catch (OperationCanceledException) { return; }
            }
        }
    }

    public async Task StopAsync()
    {
        _startCts?.Cancel();
        try { await _retryLoopTask; } catch (OperationCanceledException) { } catch { /* swallow */ }
        try { await _hub.StopAsync(); } catch { /* swallow */ }
    }

    /// <summary>Invoke a hub method, returning default (null) when the worker is offline or errors.</summary>
    private async Task<T?> TryInvokeAsync<T>(string method, params object?[] args)
    {
        try { return await _hub.InvokeCoreAsync<T>(method, args); }
        catch { return default; }
    }

    public async Task RunNowAsync(string taskId)
    {
        await _hub.InvokeAsync("RunNow", taskId);
    }

    public async Task ContinueTaskAsync(string taskId, string followUpPrompt)
    {
        await _hub.InvokeAsync("ContinueTask", taskId, followUpPrompt);
    }

    public async Task ResetTaskAsync(string taskId)
    {
        await _hub.InvokeAsync("ResetTask", taskId);
    }

    public async Task<MergeResultDto> MergeTaskAsync(string taskId, string targetBranch, bool removeWorktree, string commitMessage)
    {
        return await _hub.InvokeAsync<MergeResultDto>(
            "MergeTask", taskId, targetBranch, removeWorktree, commitMessage);
    }

    public Task<MergeTargetsDto?> GetMergeTargetsAsync(string taskId)
        => TryInvokeAsync<MergeTargetsDto>("GetMergeTargets", taskId);

    public async Task CancelTaskAsync(string taskId)
    {
        await _hub.InvokeAsync("CancelTask", taskId);
    }

    public async Task WakeQueueAsync()
    {
        await _hub.InvokeAsync("WakeQueue");
    }

    public async Task<List<AgentInfo>> GetAgentsAsync()
        => await TryInvokeAsync<List<AgentInfo>>("GetAgents") ?? [];

    public async Task RefreshAgentsAsync()
    {
        await _hub.InvokeAsync("RefreshAgents");
    }

    public Task<SeedResultDto?> RestoreDefaultAgentsAsync()
        => TryInvokeAsync<SeedResultDto>("RestoreDefaultAgents");

    private async Task SeedActiveTasksAsync()
    {
        try
        {
            var active = await _hub.InvokeAsync<List<ActiveTaskDto>>("GetActive");
            Dispatcher.UIThread.Post(() =>
            {
                ActiveTasks.Clear();
                foreach (var a in active)
                    ActiveTasks.Add(new ActiveTask(a.Slot, a.TaskId, a.StartedAt));
            });
        }
        catch (HubException)
        {
            // Expected: worker doesn't support GetActive yet
        }
        catch (Exception ex)
        {
            System.Diagnostics.Debug.WriteLine($"SeedActiveTasksAsync failed: {ex}");
        }
    }

    public async ValueTask DisposeAsync()
    {
        _startCts?.Cancel();
        try { await _retryLoopTask; } catch (OperationCanceledException) { } catch { /* swallow */ }
        await _hub.DisposeAsync();
    }

    public Task<AppSettingsDto?> GetAppSettingsAsync()
        => TryInvokeAsync<AppSettingsDto>("GetAppSettings");

    public async Task UpdateAppSettingsAsync(AppSettingsDto dto)
    {
        await _hub.InvokeAsync("UpdateAppSettings", dto);
    }

    public async Task<List<PrimeScheduleDto>> GetPrimeSchedulesAsync()
        => await TryInvokeAsync<List<PrimeScheduleDto>>("ListPrimeSchedules") ?? new List<PrimeScheduleDto>();

    public Task<PrimeScheduleDto?> UpsertPrimeScheduleAsync(PrimeScheduleDto dto)
        => TryInvokeAsync<PrimeScheduleDto>("UpsertPrimeSchedule", dto);

    public async Task DeletePrimeScheduleAsync(Guid id)
    {
        try { await _hub.InvokeAsync("DeletePrimeSchedule", id); }
        catch { /* offline */ }
    }

    private static string IsoDay(DateOnly d) => d.ToString("yyyy-MM-dd");

    public Task<string?> GetWeekReportAsync(DateOnly start, DateOnly end)
        => TryInvokeAsync<string>("GetWeekReport", IsoDay(start), IsoDay(end));

    public Task<string> GenerateWeekReportAsync(DateOnly start, DateOnly end)
        => _hub.InvokeAsync<string>("GenerateWeekReport", IsoDay(start), IsoDay(end));

    public Task<bool> RunDailyPrepNowAsync()
        => _hub.InvokeAsync<bool>("RunDailyPrepNow");

    public Task ClearMyDayAsync()
        => _hub.InvokeAsync("ClearMyDay");

    public async Task<List<DailyNoteDto>> GetDailyNotesAsync(DateOnly day)
        => await TryInvokeAsync<List<DailyNoteDto>>("GetDailyNotes", IsoDay(day)) ?? new List<DailyNoteDto>();

    public Task<DailyNoteDto?> AddDailyNoteAsync(DateOnly day, string text)
        => TryInvokeAsync<DailyNoteDto>("AddDailyNote", IsoDay(day), text);

    public async Task UpdateDailyNoteAsync(string id, string text)
        => await _hub.InvokeAsync("UpdateDailyNote", id, text);

    public async Task DeleteDailyNoteAsync(string id)
        => await _hub.InvokeAsync("DeleteDailyNote", id);

    public async Task<string> GetLastPrepLogAsync()
        => await TryInvokeAsync<string>("GetLastPrepLog") ?? string.Empty;

    public async Task UpdateListAsync(UpdateListDto dto)
    {
        await _hub.InvokeAsync("UpdateList", dto);
    }

    public async Task UpdateListConfigAsync(UpdateListConfigDto dto)
    {
        await _hub.InvokeAsync("UpdateListConfig", dto);
    }

    public Task<ListConfigDto?> GetListConfigAsync(string listId)
        => TryInvokeAsync<ListConfigDto>("GetListConfig", listId);

    public async Task UpdateTaskAgentSettingsAsync(UpdateTaskAgentSettingsDto dto)
    {
        await _hub.InvokeAsync("UpdateTaskAgentSettings", dto);
    }

    public async Task SetTaskStatusAsync(string taskId, ClaudeDo.Data.Models.TaskStatus status)
    {
        await _hub.InvokeAsync("SetTaskStatus", taskId, status.ToString());
    }

    public async Task ApproveReviewAsync(string taskId)
    {
        await _hub.InvokeAsync("ApproveReview", taskId);
    }

    public async Task RejectReviewToQueueAsync(string taskId, string feedback)
    {
        await _hub.InvokeAsync("RejectReviewToQueue", taskId, feedback);
    }

    public async Task RejectReviewToIdleAsync(string taskId)
    {
        await _hub.InvokeAsync("RejectReviewToIdle", taskId);
    }

    public async Task CancelReviewAsync(string taskId)
    {
        await _hub.InvokeAsync("CancelReview", taskId);
    }

    public Task<WorktreeCleanupDto?> CleanupFinishedWorktreesAsync(string? listId = null)
        => TryInvokeAsync<WorktreeCleanupDto>("CleanupFinishedWorktrees", listId);

    public Task<WorktreeResetDto?> ResetAllWorktreesAsync()
        => TryInvokeAsync<WorktreeResetDto>("ResetAllWorktrees");

    public async Task<List<WorktreeOverviewDto>> GetWorktreesOverviewAsync(string? listId)
        => await TryInvokeAsync<List<WorktreeOverviewDto>>("GetWorktreesOverview", listId)
           ?? new List<WorktreeOverviewDto>();

    public async Task<(bool Ok, string? Error)> SetWorktreeStateAsync(string taskId, WorktreeState newState)
    {
        try
        {
            var ok = await _hub.InvokeAsync<bool>("SetWorktreeState", taskId, newState);
            return (ok, null);
        }
        catch (HubException ex)
        {
            return (false, ex.Message);
        }
        catch (Exception)
        {
            return (false, "Worker offline.");
        }
    }

    public Task<ForceRemoveResultDto?> ForceRemoveWorktreeAsync(string taskId)
        => TryInvokeAsync<ForceRemoveResultDto>("ForceRemoveWorktree", taskId);

    public async Task<PlanningSessionStartInfo> StartPlanningSessionAsync(string taskId, CancellationToken ct = default)
        => await _hub.InvokeAsync<PlanningSessionStartInfo>("StartPlanningSessionAsync", taskId, ct);

    public async Task<PlanningSessionResumeInfo> ResumePlanningSessionAsync(string taskId, CancellationToken ct = default)
        => await _hub.InvokeAsync<PlanningSessionResumeInfo>("ResumePlanningSessionAsync", taskId, ct);

    public async Task OpenInteractiveTerminalAsync(string taskId, CancellationToken ct = default)
        => await _hub.InvokeAsync("OpenInteractiveTerminalAsync", taskId, ct);

    public async Task<DiscardPlanningOutcome> DiscardPlanningSessionAsync(string taskId, bool dequeueQueuedChildren = false, CancellationToken ct = default)
        => await _hub.InvokeAsync<DiscardPlanningOutcome>("DiscardPlanningSessionAsync", taskId, dequeueQueuedChildren, ct);

    public async Task<int> FinalizePlanningSessionAsync(string taskId, bool queueAgentTasks = true, CancellationToken ct = default)
        => await _hub.InvokeAsync<int>("FinalizePlanningSessionAsync", taskId, queueAgentTasks, ct);

    public async Task<int> GetPendingDraftCountAsync(string taskId, CancellationToken ct = default)
        => await _hub.InvokeAsync<int>("GetPendingDraftCountAsync", taskId, ct);

    public async Task<IReadOnlyList<SubtaskDiffDto>> GetPlanningAggregateAsync(string planningTaskId)
        => await TryInvokeAsync<List<SubtaskDiffDto>>("GetPlanningAggregate", planningTaskId) ?? [];

    public Task<CombinedDiffResultDto?> BuildPlanningIntegrationBranchAsync(string planningTaskId, string targetBranch)
        => TryInvokeAsync<CombinedDiffResultDto>("BuildPlanningIntegrationBranch", planningTaskId, targetBranch);

    public async Task MergeAllPlanningAsync(string planningTaskId, string targetBranch)
    {
        LastMergeAllTarget = targetBranch;
        await _hub.InvokeAsync("MergeAllPlanning", planningTaskId, targetBranch);
    }

    public async Task ContinuePlanningMergeAsync(string planningTaskId)
    {
        await _hub.InvokeAsync("ContinuePlanningMerge", planningTaskId);
    }

    public async Task AbortPlanningMergeAsync(string planningTaskId)
    {
        await _hub.InvokeAsync("AbortPlanningMerge", planningTaskId);
    }

    public async Task QueuePlanningSubtasksAsync(string parentTaskId, CancellationToken ct = default)
    {
        await _hub.InvokeAsync("QueuePlanningSubtasksAsync", parentTaskId, ct);
    }

    // IWorkerClient explicit implementations (drop typed return values)
    async Task IWorkerClient.StartPlanningSessionAsync(string taskId, CancellationToken ct)
        => await StartPlanningSessionAsync(taskId, ct);
    async Task IWorkerClient.ResumePlanningSessionAsync(string taskId, CancellationToken ct)
        => await ResumePlanningSessionAsync(taskId, ct);
    async Task<DiscardPlanningOutcome> IWorkerClient.DiscardPlanningSessionAsync(string taskId, bool dequeueQueuedChildren, CancellationToken ct)
        => await DiscardPlanningSessionAsync(taskId, dequeueQueuedChildren, ct);
    async Task IWorkerClient.FinalizePlanningSessionAsync(string taskId, bool queueAgentTasks, CancellationToken ct)
        => await FinalizePlanningSessionAsync(taskId, queueAgentTasks, ct);
    async Task<int> IWorkerClient.GetPendingDraftCountAsync(string taskId, CancellationToken ct)
        => await GetPendingDraftCountAsync(taskId, ct);

    // DTOs for deserializing hub responses
    private sealed class ActiveTaskDto
    {
        public string Slot { get; set; } = "";
        public string TaskId { get; set; } = "";
        public DateTime StartedAt { get; set; }
    }
}

public sealed record AppSettingsDto(
    string DefaultClaudeInstructions,
    string DefaultModel,
    int DefaultMaxTurns,
    string DefaultPermissionMode,
    int MaxParallelExecutions,
    string WorktreeStrategy,
    string? CentralWorktreeRoot,
    bool WorktreeAutoCleanupEnabled,
    int WorktreeAutoCleanupDays,
    string? ReportExcludedPaths,
    int StandupWeekday,
    int DailyPrepMaxTasks);

public sealed record WorktreeCleanupDto(int Removed);
public sealed record WorktreeResetDto(int Removed, int TasksAffected, bool Blocked, int RunningTasks);
public record MergeResultDto(string Status, IReadOnlyList<string> ConflictFiles, string? ErrorMessage);
public record MergeTargetsDto(string DefaultBranch, IReadOnlyList<string> LocalBranches);
public sealed record UpdateListDto(string Id, string Name, string? WorkingDir, string DefaultCommitType);
public sealed record UpdateListConfigDto(string ListId, string? Model, string? SystemPrompt, string? AgentPath, int? MaxTurns = null);
public sealed record UpdateTaskAgentSettingsDto(string TaskId, string? Model, string? SystemPrompt, string? AgentPath, int? MaxTurns = null);
public sealed record ListConfigDto(string? Model, string? SystemPrompt, string? AgentPath, int? MaxTurns = null);
public sealed record SeedResultDto(int Copied, int Skipped);

public sealed record WorktreeOverviewDto(
    string TaskId,
    string TaskTitle,
    ClaudeDo.Data.Models.TaskStatus TaskStatus,
    string ListId,
    string ListName,
    string Path,
    string BranchName,
    string BaseCommit,
    WorktreeState State,
    string? DiffStat,
    DateTime CreatedAt,
    bool PathExistsOnDisk);

public sealed record ForceRemoveResultDto(bool Removed, string? Reason);