using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
using Orchard.Core.Common.Models;

namespace Orchard.Core.Common.Services {
    public class RoutableService : IRoutableService {
        public void FillSlug<TModel>(TModel model) where TModel : RoutableAspect {
            if (!string.IsNullOrEmpty(model.Slug) || string.IsNullOrEmpty(model.Title))
                return;

            var slug = model.Title;
            var dissallowed = new Regex(@"[/:?#\[\]@!$&'()*+,;=\s]+");

            slug = dissallowed.Replace(slug, "-");
            slug = slug.Trim('-');

            if (slug.Length > 1000)
                slug = slug.Substring(0, 1000);

            model.Slug = slug;
        }

        public void FillSlug<TModel>(TModel model, Func<string, string> generateSlug) where TModel : RoutableAspect {
            if (!string.IsNullOrEmpty(model.Slug) || string.IsNullOrEmpty(model.Title))
                return;

            model.Slug = generateSlug(model.Title);
        }



        public string GenerateUniqueSlug(string slugCandidate, IEnumerable<string> existingSlugs) {
            int? version = existingSlugs
                .Select(s => {
                            int v;
                            string[] slugParts = s.Split(new[] { slugCandidate }, StringSplitOptions.RemoveEmptyEntries);
                            if (slugParts.Length == 0) {
                                return 2;
                            }

                            return int.TryParse(slugParts[0].TrimStart('-'), out v)
                                       ? (int?) ++v
                                       : null;
                        })
                .OrderBy(i => i)
                .LastOrDefault();

            return version != null
                       ? string.Format("{0}-{1}", slugCandidate, version)
                       : slugCandidate;
        }
    }
}