using System;
using System.Collections.Generic;
using System.Linq;
using Jellyfin.Data.Enums;
using Jellyfin.Plugin.JRay.Models;
using Jellyfin.Plugin.JRay.Services.Interfaces;
using MediaBrowser.Controller.Entities;
using MediaBrowser.Controller.Library;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;

namespace Jellyfin.Plugin.JRay.Controllers;

/// <summary>
/// Lets a remote extraction worker discover which library items still need
/// to be processed.
/// </summary>
[ApiController]
[Route("Plugins/JRay/Tasks")]
[Authorize(Roles = "Administrator")]
public class TasksController : ControllerBase
{
    private const int DefaultLimit = 10;
    private const int MaxLimit = 100;

    private readonly ILibraryManager _libraryManager;
    private readonly ITruthDataService _truthDataService;

    /// <summary>
    /// Initializes a new instance of the <see cref="TasksController"/> class.
    /// </summary>
    /// <param name="libraryManager">The Jellyfin library manager.</param>
    /// <param name="truthDataService">The truth data service.</param>
    public TasksController(ILibraryManager libraryManager, ITruthDataService truthDataService)
    {
        _libraryManager = libraryManager;
        _truthDataService = truthDataService;
    }

    /// <summary>
    /// Gets a random sample of movies/episodes that have no truth data yet.
    /// </summary>
    /// <param name="limit">The maximum number of items to return (default 10, max 100).</param>
    /// <returns>Up to <paramref name="limit"/> items with no truth data, in random order.</returns>
    [HttpGet("Pending")]
    [ProducesResponseType(StatusCodes.Status200OK)]
    public ActionResult<IEnumerable<PendingExtractionItem>> GetPending([FromQuery] int limit = DefaultLimit)
    {
        var effectiveLimit = Math.Clamp(limit, 1, MaxLimit);

        var items = _libraryManager.GetItemList(new InternalItemsQuery
        {
            IncludeItemTypes = new[] { BaseItemKind.Movie, BaseItemKind.Episode },
            IsVirtualItem = false,
            Recursive = true,
        });

        var pending = items
            .Where(item => !string.IsNullOrEmpty(item.Path) && !_truthDataService.HasTruth(item.Id, item.Path))
            .OrderBy(_ => Random.Shared.Next())
            .Take(effectiveLimit)
            .Select(item => new PendingExtractionItem
            {
                ItemId = item.Id,
                Path = item.Path,
                Name = item.Name
            });

        return Ok(pending);
    }
}