using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Routing;
using JetBrains.Annotations;
using Orchard.Environment.Extensions;
using Orchard.Logging;
using Orchard.ContentManagement;
using Orchard.Settings;
using Orchard.Themes.Models;

namespace Orchard.Themes.Services {
    [UsedImplicitly]
    public class ThemeService : IThemeService {
        private readonly IExtensionManager _extensionManager;
        private readonly IEnumerable<IThemeSelector> _themeSelectors;

        public ThemeService(
            IExtensionManager extensionManager,
            IEnumerable<IThemeSelector> themeSelectors) {
            _extensionManager = extensionManager;
            _themeSelectors = themeSelectors;
            Logger = NullLogger.Instance;
        }

        public ILogger Logger { get; set; }
        protected virtual ISite CurrentSite { get; [UsedImplicitly] private set; }

        public ITheme GetSiteTheme() {
            string currentThemeName = CurrentSite.As<ThemeSiteSettingsPart>().Record.CurrentThemeName;

            if (String.IsNullOrEmpty(currentThemeName)) {
                return null;
            }

            return GetThemeByName(currentThemeName);
        }

        public void SetSiteTheme(string themeName) {
            if (GetThemeByName(themeName) != null) {
                CurrentSite.As<ThemeSiteSettingsPart>().Record.CurrentThemeName = themeName;
            }
        }

        public ITheme GetRequestTheme(RequestContext requestContext) {

            var requestTheme = _themeSelectors
                .Select(x => x.GetTheme(requestContext))
                .Where(x => x != null)
                .OrderByDescending(x => x.Priority);

            if (requestTheme.Count() < 1)
                return null;

            foreach (var theme in requestTheme) {
                var t = GetThemeByName(theme.ThemeName);
                if (t != null)
                    return t;
            }

            return null;
        }

        public ITheme GetThemeByName(string name) {
            foreach (var descriptor in _extensionManager.AvailableExtensions()) {
                if (String.Equals(descriptor.Name, name, StringComparison.OrdinalIgnoreCase)) {
                    return new Theme {
                                         Author = descriptor.Author ?? String.Empty,
                                         Description = descriptor.Description ?? String.Empty,
                                         DisplayName = descriptor.DisplayName ?? String.Empty,
                                         HomePage = descriptor.WebSite ?? String.Empty,
                                         ThemeName = descriptor.Name,
                                         Version = descriptor.Version ?? String.Empty,
                                         Tags = descriptor.Tags ?? String.Empty,
                                         Zones = descriptor.Zones ?? String.Empty,
                                     };
                }
            }
            return null;
        }

        public IEnumerable<ITheme> GetInstalledThemes() {
            List<ITheme> themes = new List<ITheme>();
            foreach (var descriptor in _extensionManager.AvailableExtensions()) {
                if (String.Equals(descriptor.ExtensionType, "Theme", StringComparison.OrdinalIgnoreCase)) {
                    Theme theme = new Theme {
                                                Author = descriptor.Author ?? String.Empty,
                                                Description = descriptor.Description ?? String.Empty,
                                                DisplayName = descriptor.DisplayName ?? String.Empty,
                                                HomePage = descriptor.WebSite ?? String.Empty,
                                                ThemeName = descriptor.Name,
                                                Version = descriptor.Version ?? String.Empty,
                                                Tags = descriptor.Tags ?? String.Empty,
                                                Zones = descriptor.Zones ?? String.Empty,
                                            };
                    if (!theme.Tags.Contains("hidden")) {
                        themes.Add(theme);
                    }
                }
            }
            return themes;
        }

        public void InstallTheme(HttpPostedFileBase file) {
            _extensionManager.InstallExtension("Theme", file);
        }

        public void UninstallTheme(string themeName) {
            _extensionManager.UninstallExtension("Theme", themeName);
        }
    }
}