using System;
using System.Collections.Generic;
using System.Linq;
using JetBrains.Annotations;
using Portoa.Persistence;
using VideoGameQuotes.Api;

namespace VideoGameQuotes.Web.Services {
	public interface IQuoteService {
		Game GetGame(int id);
		IEnumerable<Game> GetAllGames();
		IEnumerable<GamingSystem> GetAllSystems();
		IEnumerable<Publisher> GetAllPublishers();
		IEnumerable<Category> GetAllCategories();
		Quote SaveQuote(Quote quote);
		Quote GetQuote(int id);
		Publisher GetPublisher(int id);
		GamingSystem GetSystem(int systemId);
		Category GetCategory(int categoryId);
		Category SaveCategory(Category category);
		IEnumerable<Quote> GetMostRecentQuotes(int limit);
		[CanBeNull]
		Quote GetRandomQuote();
		IEnumerable<Quote> GetBestQuotes(int start, int end);
		Vote SaveVote(Vote vote);
		Vote GetVoteOrCreateNew(Quote quote, User voter);
	}

	public class QuoteService : IQuoteService {
		private readonly IRepository<Quote> quoteRepository;
		private readonly IRepository<Game> gameRepository;
		private readonly IRepository<GamingSystem> systemRepository;
		private readonly IRepository<Publisher> publisherRepository;
		private readonly IRepository<Category> categoryRepository;
		private readonly IRepository<Vote> voteRepository;

		public QuoteService(
			IRepository<Quote> quoteRepository,
			IRepository<Game> gameRepository,
			IRepository<GamingSystem> systemRepository,
			IRepository<Publisher> publisherRepository, 
			IRepository<Category> categoryRepository,
			IRepository<Vote> voteRepository
		) {
			this.quoteRepository = quoteRepository;
			this.categoryRepository = categoryRepository;
			this.voteRepository = voteRepository;
			this.gameRepository = gameRepository;
			this.systemRepository = systemRepository;
			this.publisherRepository = publisherRepository;
		}

		[UnitOfWork]
		public Game GetGame(int id) {
			return gameRepository.FindById(id);
		}

		[UnitOfWork]
		public IEnumerable<Game> GetAllGames() {
			return gameRepository.Records;
		}

		[UnitOfWork]
		public IEnumerable<GamingSystem> GetAllSystems() {
			return systemRepository.Records;
		}

		[UnitOfWork]
		public IEnumerable<Publisher> GetAllPublishers() {
			return publisherRepository.Records;
		}

		[UnitOfWork]
		public IEnumerable<Category> GetAllCategories() {
			return categoryRepository.Records;
		}

		[UnitOfWork]
		public Quote SaveQuote(Quote quote) {
			return quoteRepository.Save(quote);
		}

		[UnitOfWork]
		public Quote GetQuote(int id) {
			return quoteRepository.FindById(id);
		}

		[UnitOfWork]
		public Publisher GetPublisher(int id) {
			return publisherRepository.FindById(id);
		}

		[UnitOfWork]
		public GamingSystem GetSystem(int systemId) {
			return systemRepository.FindById(systemId);
		}

		[UnitOfWork]
		public Category GetCategory(int categoryId) {
			return categoryRepository.FindById(categoryId);
		}

		[UnitOfWork]
		public Category SaveCategory(Category category) {
			return categoryRepository.Save(category);
		}

		[UnitOfWork]
		public IEnumerable<Quote> GetMostRecentQuotes(int limit) {
			return quoteRepository
				.Records
				.OrderByDescending(quote => quote.Created)
				.Take(limit);
		}

		[UnitOfWork]
		public Quote GetRandomQuote() {
			var quotes = quoteRepository.Records.ToArray();
			if (quotes.Length == 0) {
				return null;
			}

			return quotes[new Random().Next(quotes.Length)];
		}

		[UnitOfWork]
		public IEnumerable<Quote> GetBestQuotes(int start, int end) {
			var records = quoteRepository.Records.ToArray();

			return records
				.OrderByDescending(quote => quote.NetVotes)
				.ThenByDescending(quote => quote.UpVotes)
				.Skip(start)
				.Take(end - start + 1);
		}

		[UnitOfWork]
		public Vote SaveVote(Vote vote) {
			return voteRepository.Save(vote);
		}

		[UnitOfWork]
		public Vote GetVoteOrCreateNew(Quote quote, User voter) {
			var vote = voteRepository.Records.SingleOrDefault(v => v.Quote == quote && v.Voter == voter);
			return vote ?? new Vote {
				Quote = quote,
				Voter = voter
			};
		}
	}
}