using System.Security.Claims;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.SignalR;
using PlotLine.Data;
using PlotLine.Models;
using PlotLine.Services;
using PlotLine.ViewModels;

namespace PlotLine.Hubs;

[Authorize]
public sealed class StoryIntelligenceHub(
    IStoryIntelligenceService storyIntelligence,
    IStoryIntelligenceResultRepository persistedRuns,
    IOnboardingStoryIntelligenceService onboardingStoryIntelligence) : Hub
{
    public override async Task OnConnectedAsync()
    {
        if (TryGetUserId(out var userId))
        {
            await Groups.AddToGroupAsync(Context.ConnectionId, UserGroup(userId));
        }

        await base.OnConnectedAsync();
    }

    public async Task<StoryIntelligenceJobProgress?> WatchStoryIntelligenceJob(Guid jobId)
    {
        var userId = RequireUserId();
        await Groups.AddToGroupAsync(Context.ConnectionId, UserGroup(userId));
        return await storyIntelligence.GetProgressForUserAsync(userId, jobId);
    }

    public async Task<StoryIntelligenceRunProgressEvent?> WatchStoryIntelligenceRun(int runId)
    {
        var userId = RequireUserId();
        await Groups.AddToGroupAsync(Context.ConnectionId, UserGroup(userId));

        var run = await persistedRuns.GetRunAsync(runId);
        return run is null || run.UserID != userId
            ? null
            : ToRunProgress(run, "Current status");
    }

    public async Task<StoryIntelligenceProgressViewModel?> WatchOnboardingStoryIntelligenceBatch(Guid batchId)
    {
        var userId = RequireUserId();
        await Groups.AddToGroupAsync(Context.ConnectionId, UserGroup(userId));
        return await onboardingStoryIntelligence.GetProgressAsync(batchId);
    }

    public static string UserGroup(int userId) => $"story-intelligence:{userId}";

    private static StoryIntelligenceRunProgressEvent ToRunProgress(StoryIntelligenceSavedRun run, string eventType)
    {
        var completedScenes = run.CompletedScenes ?? 0;
        var totalScenes = run.TotalDetectedScenes ?? 0;
        var elapsedMs = run.TotalDurationMs ?? Math.Max(0, Convert.ToInt64((DateTime.UtcNow - run.StartedUtc).TotalMilliseconds));

        return new StoryIntelligenceRunProgressEvent
        {
            RunID = run.StoryIntelligenceRunID,
            UserID = run.UserID,
            ProjectID = run.ProjectID,
            BookID = run.BookID,
            ChapterID = run.ChapterID,
            ChapterNumber = run.ChapterNumber,
            Status = run.Status,
            CurrentStage = run.CurrentStage ?? string.Empty,
            CurrentMessage = run.CurrentMessage ?? string.Empty,
            EventType = eventType,
            TotalDetectedScenes = run.TotalDetectedScenes,
            CompletedScenes = run.CompletedScenes,
            FailedScenes = run.FailedScenes,
            TotalTokens = run.TotalTokens,
            TotalDurationMs = elapsedMs,
            ElapsedTime = FormatDuration(elapsedMs),
            EstimatedRemaining = EstimateRemaining(elapsedMs, completedScenes, totalScenes),
            ErrorMessage = run.ErrorMessage,
            UpdatedUtc = run.UpdatedUtc,
            IsActive = run.Status is StoryIntelligenceRunStatuses.Pending or StoryIntelligenceRunStatuses.Running,
            IsCompleted = run.Status is StoryIntelligenceRunStatuses.Completed or StoryIntelligenceRunStatuses.CompletedWithWarnings
        };
    }

    private static string FormatDuration(long? milliseconds)
    {
        var elapsed = TimeSpan.FromMilliseconds(Math.Max(0, milliseconds ?? 0));
        if (elapsed.TotalMinutes >= 1)
        {
            return $"{Math.Max(1, (int)Math.Round(elapsed.TotalMinutes)):N0} min";
        }

        return $"{Math.Max(0, (int)Math.Round(elapsed.TotalSeconds)):N0} sec";
    }

    private static string? EstimateRemaining(long elapsedMs, int completedScenes, int totalScenes)
    {
        if (completedScenes <= 0 || totalScenes <= completedScenes)
        {
            return totalScenes > 0 && totalScenes == completedScenes ? "Nearly finished" : "Calculating";
        }

        var averageSceneMs = elapsedMs / Math.Max(1, completedScenes);
        return FormatDuration(averageSceneMs * (totalScenes - completedScenes));
    }

    private int RequireUserId()
        => TryGetUserId(out var userId) ? userId : throw new HubException("Sign in to use Story Intelligence.");

    private bool TryGetUserId(out int userId)
        => int.TryParse(Context.User?.FindFirstValue(ClaimTypes.NameIdentifier), out userId);
}