using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using API.Constants;
using API.Data;
using API.Data.Repositories;
using API.DTOs.SeriesDetail;
using API.Extensions;
using API.Helpers.Builders;
using API.Services;
using API.Services.Plus;
using AutoMapper;
using EasyCaching.Core;
using Hangfire;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;

namespace API.Controllers;

public class ReviewController : BaseApiController
{
    private readonly ILogger<ReviewController> _logger;
    private readonly IUnitOfWork _unitOfWork;
    private readonly ILicenseService _licenseService;
    private readonly IMapper _mapper;
    private readonly IReviewService _reviewService;
    private readonly IScrobblingService _scrobblingService;
    private readonly IEasyCachingProvider _cacheProvider;
    public const string CacheKey = "review_";

    public ReviewController(ILogger<ReviewController> logger, IUnitOfWork unitOfWork, ILicenseService licenseService,
        IMapper mapper, IReviewService reviewService, IScrobblingService scrobblingService,
        IEasyCachingProviderFactory cachingProviderFactory)
    {
        _logger = logger;
        _unitOfWork = unitOfWork;
        _licenseService = licenseService;
        _mapper = mapper;
        _reviewService = reviewService;
        _scrobblingService = scrobblingService;

        _cacheProvider = cachingProviderFactory.GetCachingProvider(EasyCacheProfiles.KavitaPlusReviews);
    }


    /// <summary>
    /// Fetches reviews from the server for a given series
    /// </summary>
    /// <param name="seriesId"></param>
    [HttpGet]
    [ResponseCache(CacheProfileName = ResponseCacheProfiles.KavitaPlus, VaryByQueryKeys = new []{"seriesId"})]
    public async Task<ActionResult<IEnumerable<UserReviewDto>>> GetReviews(int seriesId)
    {
        var userId = User.GetUserId();
        var userRatings = (await _unitOfWork.UserRepository.GetUserRatingDtosForSeriesAsync(seriesId, userId))
            .Where(r => !string.IsNullOrEmpty(r.Body) && !string.IsNullOrEmpty(r.Tagline))
            .ToList();
        if (!await _licenseService.HasActiveLicense())
        {
            return Ok(userRatings);
        }

        var cacheKey = CacheKey + seriesId;
        IList<UserReviewDto> externalReviews;

        var result = await _cacheProvider.GetAsync<IEnumerable<UserReviewDto>>(cacheKey);
        if (result.HasValue)
        {
            externalReviews = result.Value.ToList();
        }
        else
        {
            var reviews = (await _reviewService.GetReviewsForSeries(userId, seriesId)).ToList();
            externalReviews = SelectSpectrumOfReviews(reviews);

            await _cacheProvider.SetAsync(cacheKey, externalReviews, TimeSpan.FromHours(10));
            _logger.LogDebug("Caching external reviews for {Key}", cacheKey);
        }


        // Fetch external reviews and splice them in
        userRatings.AddRange(externalReviews);


        return Ok(userRatings);
    }

    private static IList<UserReviewDto> SelectSpectrumOfReviews(IList<UserReviewDto> reviews)
    {
        IList<UserReviewDto> externalReviews;
        var totalReviews = reviews.Count;

        if (totalReviews > 10)
        {
            var stepSize = Math.Max((totalReviews - 4) / 8, 1);

            var selectedReviews = new List<UserReviewDto>()
            {
                reviews[0],
                reviews[1],
            };
            for (var i = 2; i < totalReviews - 2; i += stepSize)
            {
                selectedReviews.Add(reviews[i]);

                if (selectedReviews.Count >= 8)
                    break;
            }

            selectedReviews.Add(reviews[totalReviews - 2]);
            selectedReviews.Add(reviews[totalReviews - 1]);

            externalReviews = selectedReviews;
        }
        else
        {
            externalReviews = reviews;
        }

        return externalReviews;
    }

    /// <summary>
    /// Updates the review for a given series
    /// </summary>
    /// <param name="dto"></param>
    /// <returns></returns>
    [HttpPost]
    public async Task<ActionResult<UserReviewDto>> UpdateReview(UpdateUserReviewDto dto)
    {
        var user = await _unitOfWork.UserRepository.GetUserByIdAsync(User.GetUserId(), AppUserIncludes.Ratings);
        if (user == null) return Unauthorized();

        var ratingBuilder = new RatingBuilder(user.Ratings.FirstOrDefault(r => r.SeriesId == dto.SeriesId));

        var rating = ratingBuilder
            .WithBody(dto.Body)
            .WithSeriesId(dto.SeriesId)
            .WithTagline(dto.Tagline)
            .Build();

        if (rating.Id == 0)
        {
            user.Ratings.Add(rating);
        }
        _unitOfWork.UserRepository.Update(user);

        await _unitOfWork.CommitAsync();


        BackgroundJob.Enqueue(() =>
            _scrobblingService.ScrobbleReviewUpdate(user.Id, dto.SeriesId, dto.Tagline, dto.Body));
        return Ok(_mapper.Map<UserReviewDto>(rating));
    }
}