using System;
using System.Collections.Generic;
using System.Text;

using GoMovies2020.Shared.Models;
using GoMovies2020.Shared.ViewModels;
using GoMovies2020.Shared.Enums;
using System.Linq;


namespace GoMovies2020.Shared.Queryables
{
    public static class FilmFilterQueries
    {
        public static IQueryable<Film> ApplyQueryFilter(IQueryable<Film> films, FilmsFilterViewModel filmsFilter)
        {
            // Check if a FilterField has been specified (i.e. not set to No Filter - Show All)
            // Check if a FilterSearchString, i.e. something to search for, has been specified

            if (filmsFilter.FilterField != FilmFilterColumns.NoFilter && !string.IsNullOrEmpty(filmsFilter.FilterSearchString))
            {
                // What filter field has been selected by the user?
                switch (filmsFilter.FilterField)
                {
                    case FilmFilterColumns.ByTitle: // Search the title
                        return films.Where(f => f.Title.Contains(filmsFilter.FilterSearchString));

                    case FilmFilterColumns.ByGenre: // Search the genre
                        return films.Where(f => f.Genre.Contains(filmsFilter.FilterSearchString));

                    case FilmFilterColumns.ByCast: // Search the cast
                        return films.Where(f => f.Cast.Contains(filmsFilter.FilterSearchString));

                    case FilmFilterColumns.ByTitleGenreCast: // Search the title, genre, or cast
                        return films.Where(f => f.Title.Contains(filmsFilter.FilterSearchString) 
                                                || f.Genre.Contains(filmsFilter.FilterSearchString) 
                                                || f.Cast.Contains(filmsFilter.FilterSearchString));

                    case FilmFilterColumns.ByReviewRating: // Search the review rating
                        decimal reviewRatingFilter = 0;
                        decimal.TryParse(filmsFilter.FilterSearchString, out reviewRatingFilter);
                        return films.Where(f => f.ReviewRating >= reviewRatingFilter);

                    case FilmFilterColumns.ByReleaseYear: // Search the release year
                        int releaseYear = 0;
                        int.TryParse(filmsFilter.FilterSearchString, out releaseYear);

                        if (releaseYear > 0)
                        {
                            return films.Where(f => f.CinemaReleaseDate.Year == releaseYear);
                        }

                        return films;

                        // TODO: complete the rest (Cast, Review Rating, Release Year)
                }
            }

            return films;
        }

        public static IQueryable<Film> ApplyQuerySort(IQueryable<Film> films, FilmsFilterViewModel filmsFilter)
        {
            // What column to sort the results by has been select by the user?
            switch (filmsFilter.SortBy)
            {
                case FilmSortOptions.ByTitle: // Sort by Title ASC
                    return films.OrderBy(f => f.Title);

                case FilmSortOptions.ByReleaseDate: // Sort by Cinema Release Date ASC
                    return films.OrderBy(f => f.CinemaReleaseDate);

                case FilmSortOptions.ByReleaseDateDesc: // Sort by Cinema Release Date DESC
                    return films.OrderByDescending(f => f.CinemaReleaseDate);

                case FilmSortOptions.ByReviewRating: // Sort by Review Rating ASC
                    return films.OrderBy(f => f.ReviewRating);

                case FilmSortOptions.ByReviewRatingDesc: // Sort by Review Rating DESC
                    return films.OrderByDescending(f => f.ReviewRating);


                    // TODO: complete the rest (Release Date DESC, Review Rating, Review Rating DESC)
            }

            return films;
        }

        public static IQueryable<Film> ApplyQueryFetchRange(IQueryable<Film> films, FilmsFilterViewModel filmsFilter)
        {
            return films.Skip(filmsFilter.SkipCount).Take(filmsFilter.PageSize);
        }
    }
}