using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using System.Xml.XPath;
using Umbraco.Core;
using Umbraco.Core.Dictionary;
using Umbraco.Core.Models.PublishedContent;
using Umbraco.Core.Strings;
using Umbraco.Core.Templates;
using Umbraco.Core.Xml;

namespace Umbraco.Web.Website
{
    /// <summary>
    /// A helper class that provides many useful methods and functionality for using Umbraco in templates
    /// </summary>
    /// <remarks>
    /// This object is a request based lifetime
    /// </remarks>
    public class UmbracoHelper
    {
        private readonly IPublishedContentQuery _publishedContentQuery;
        private readonly IUmbracoComponentRenderer _componentRenderer;
        private readonly ICultureDictionaryFactory _cultureDictionaryFactory;

        private IPublishedContent _currentPage;
        private ICultureDictionary _cultureDictionary;

        #region Constructors

        /// <summary>
        /// Initializes a new instance of <see cref="UmbracoHelper"/>.
        /// </summary>
        /// <param name="currentPage">The <see cref="IPublishedContent"/> item assigned to the helper.</param>
        /// <param name="cultureDictionary"></param>
        /// <param name="componentRenderer"></param>
        /// <param name="publishedContentQuery"></param>
        /// <remarks>Sets the current page to the context's published content request's content item.</remarks>
        public UmbracoHelper(ICultureDictionaryFactory cultureDictionary,
            IUmbracoComponentRenderer componentRenderer,
            IPublishedContentQuery publishedContentQuery)
        {
            _cultureDictionaryFactory = cultureDictionary ?? throw new ArgumentNullException(nameof(cultureDictionary));
            _componentRenderer = componentRenderer ?? throw new ArgumentNullException(nameof(componentRenderer));
            _publishedContentQuery = publishedContentQuery ?? throw new ArgumentNullException(nameof(publishedContentQuery));
        }

        /// <summary>
        /// Initializes a new empty instance of <see cref="UmbracoHelper"/>.
        /// </summary>
        /// <remarks>For tests - nothing is initialized.</remarks>
        internal UmbracoHelper()
        { }

        #endregion


        /// <summary>
        /// Gets (or sets) the current <see cref="IPublishedContent"/> item assigned to the UmbracoHelper.
        /// </summary>
        /// <remarks>
        /// <para>
        /// Note that this is the assigned IPublishedContent item to the
        /// UmbracoHelper, this is not necessarily the Current IPublishedContent
        /// item being rendered that is assigned to the UmbracoContext.
        /// This IPublishedContent object is contextual to the current UmbracoHelper instance.
        /// </para>
        ///<para>
        /// In some cases accessing this property will throw an exception if
        /// there is not IPublishedContent assigned to the Helper this will
        /// only ever happen if the Helper is constructed via DI during a non front-end request.
        /// </para>
        /// </remarks>
        /// <exception cref="InvalidOperationException">Thrown if the
        /// UmbracoHelper is constructed with an UmbracoContext and it is not a
        /// front-end request.</exception>
        public IPublishedContent AssignedContentItem
        {
            get
            {
                if (_currentPage != null)
                {
                    return _currentPage;
                }

                throw new InvalidOperationException(
                    $"Cannot return the {nameof(IPublishedContent)} because the {nameof(UmbracoHelper)} was not constructed with an {nameof(IPublishedContent)}."
                    );

            }
            set => _currentPage = value;
        }

        /// <summary>
        /// Renders the template for the specified pageId and an optional altTemplateId
        /// </summary>
        /// <param name="contentId">The content id</param>
        /// <param name="altTemplateId">If not specified, will use the template assigned to the node</param>
        public async Task<IHtmlEncodedString> RenderTemplateAsync(int contentId, int? altTemplateId = null)
            => await _componentRenderer.RenderTemplateAsync(contentId, altTemplateId);

        #region RenderMacro

        /// <summary>
        /// Renders the macro with the specified alias.
        /// </summary>
        /// <param name="alias">The alias.</param>
        /// <returns></returns>
        public IHtmlEncodedString RenderMacro(string alias)
        {
            return _componentRenderer.RenderMacro(AssignedContentItem?.Id ?? 0, alias, null);
        }

        /// <summary>
        /// Renders the macro with the specified alias, passing in the specified parameters.
        /// </summary>
        /// <param name="alias">The alias.</param>
        /// <param name="parameters">The parameters.</param>
        /// <returns></returns>
        public IHtmlEncodedString RenderMacro(string alias, object parameters)
        {
            return _componentRenderer.RenderMacro(AssignedContentItem?.Id ?? 0, alias, parameters?.ToDictionary<object>());
        }

        /// <summary>
        /// Renders the macro with the specified alias, passing in the specified parameters.
        /// </summary>
        /// <param name="alias">The alias.</param>
        /// <param name="parameters">The parameters.</param>
        /// <returns></returns>
        public IHtmlEncodedString RenderMacro(string alias, IDictionary<string, object> parameters)
        {
            return _componentRenderer.RenderMacro(AssignedContentItem?.Id ?? 0, alias, parameters);
        }

        #endregion

        #region Dictionary

        /// <summary>
        /// Returns the dictionary value for the key specified
        /// </summary>
        /// <param name="key"></param>
        /// <returns></returns>
        public string GetDictionaryValue(string key)
        {
            return CultureDictionary[key];
        }

        /// <summary>
        /// Returns the dictionary value for the key specified, and if empty returns the specified default fall back value
        /// </summary>
        /// <param name="key">key of dictionary item</param>
        /// <param name="altText">fall back text if dictionary item is empty - Name altText to match Umbraco.Field</param>
        /// <returns></returns>
        public string GetDictionaryValue(string key, string altText)
        {
            var dictionaryValue = GetDictionaryValue(key);
            if (String.IsNullOrWhiteSpace(dictionaryValue))
            {
                dictionaryValue = altText;
            }
            return dictionaryValue;
        }

        /// <summary>
        /// Returns the ICultureDictionary for access to dictionary items
        /// </summary>
        public ICultureDictionary CultureDictionary => _cultureDictionary ??= _cultureDictionaryFactory.CreateDictionary();

        #endregion



        #region Content

        /// <summary>
        /// Gets a content item from the cache.
        /// </summary>
        /// <param name="id">The unique identifier, or the key, of the content item.</param>
        /// <returns>The content, or null of the content item is not in the cache.</returns>
        public IPublishedContent Content(object id)
        {
            return ContentForObject(id);
        }

        private IPublishedContent ContentForObject(object id) => _publishedContentQuery.Content(id);

        public IPublishedContent ContentSingleAtXPath(string xpath, params XPathVariable[] vars)
        {
            return _publishedContentQuery.ContentSingleAtXPath(xpath, vars);
        }

        /// <summary>
        /// Gets a content item from the cache.
        /// </summary>
        /// <param name="id">The unique identifier of the content item.</param>
        /// <returns>The content, or null of the content item is not in the cache.</returns>
        public IPublishedContent Content(int id) => _publishedContentQuery.Content(id);

        /// <summary>
        /// Gets a content item from the cache.
        /// </summary>
        /// <param name="id">The key of the content item.</param>
        /// <returns>The content, or null of the content item is not in the cache.</returns>
        public IPublishedContent Content(Guid id) => _publishedContentQuery.Content(id);

        /// <summary>
        /// Gets a content item from the cache.
        /// </summary>
        /// <param name="id">The unique identifier, or the key, of the content item.</param>
        /// <returns>The content, or null of the content item is not in the cache.</returns>
        public IPublishedContent Content(string id) => _publishedContentQuery.Content(id);

        public IPublishedContent Content(Udi id) => _publishedContentQuery.Content(id);

        /// <summary>
        /// Gets content items from the cache.
        /// </summary>
        /// <param name="ids">The unique identifiers, or the keys, of the content items.</param>
        /// <returns>The content items that were found in the cache.</returns>
        /// <remarks>Does not support mixing identifiers and keys.</remarks>
        public IEnumerable<IPublishedContent> Content(params object[] ids) => _publishedContentQuery.Content(ids);

        /// <summary>
        /// Gets the contents corresponding to the identifiers.
        /// </summary>
        /// <param name="ids">The content identifiers.</param>
        /// <returns>The existing contents corresponding to the identifiers.</returns>
        /// <remarks>If an identifier does not match an existing content, it will be missing in the returned value.</remarks>
        public IEnumerable<IPublishedContent> Content(params Udi[] ids) => _publishedContentQuery.Content(ids);

        /// <summary>
        /// Gets the contents corresponding to the identifiers.
        /// </summary>
        /// <param name="ids">The content identifiers.</param>
        /// <returns>The existing contents corresponding to the identifiers.</returns>
        /// <remarks>If an identifier does not match an existing content, it will be missing in the returned value.</remarks>
        public IEnumerable<IPublishedContent> Content(params GuidUdi[] ids) => _publishedContentQuery.Content(ids);

        private IEnumerable<IPublishedContent> ContentForObjects(IEnumerable<object> ids) => _publishedContentQuery.Content(ids);

        /// <summary>
        /// Gets content items from the cache.
        /// </summary>
        /// <param name="ids">The unique identifiers of the content items.</param>
        /// <returns>The content items that were found in the cache.</returns>
        public IEnumerable<IPublishedContent> Content(params int[] ids) => _publishedContentQuery.Content(ids);

        /// <summary>
        /// Gets content items from the cache.
        /// </summary>
        /// <param name="ids">The keys of the content items.</param>
        /// <returns>The content items that were found in the cache.</returns>
        public IEnumerable<IPublishedContent> Content(params Guid[] ids) => _publishedContentQuery.Content(ids);

        /// <summary>
        /// Gets content items from the cache.
        /// </summary>
        /// <param name="ids">The unique identifiers, or the keys, of the content items.</param>
        /// <returns>The content items that were found in the cache.</returns>
        /// <remarks>Does not support mixing identifiers and keys.</remarks>
        public IEnumerable<IPublishedContent> Content(params string[] ids) => _publishedContentQuery.Content(ids);

        /// <summary>
        /// Gets the contents corresponding to the identifiers.
        /// </summary>
        /// <param name="ids">The content identifiers.</param>
        /// <returns>The existing contents corresponding to the identifiers.</returns>
        /// <remarks>If an identifier does not match an existing content, it will be missing in the returned value.</remarks>
        public IEnumerable<IPublishedContent> Content(IEnumerable<object> ids) => _publishedContentQuery.Content(ids);

        /// <summary>
        /// Gets the contents corresponding to the identifiers.
        /// </summary>
        /// <param name="ids">The content identifiers.</param>
        /// <returns>The existing contents corresponding to the identifiers.</returns>
        /// <remarks>If an identifier does not match an existing content, it will be missing in the returned value.</remarks>
        public IEnumerable<IPublishedContent> Content(IEnumerable<Udi> ids) => _publishedContentQuery.Content(ids);

        /// <summary>
        /// Gets the contents corresponding to the identifiers.
        /// </summary>
        /// <param name="ids">The content identifiers.</param>
        /// <returns>The existing contents corresponding to the identifiers.</returns>
        /// <remarks>If an identifier does not match an existing content, it will be missing in the returned value.</remarks>
        public IEnumerable<IPublishedContent> Content(IEnumerable<GuidUdi> ids) => _publishedContentQuery.Content(ids);

        /// <summary>
        /// Gets the contents corresponding to the identifiers.
        /// </summary>
        /// <param name="ids">The content identifiers.</param>
        /// <returns>The existing contents corresponding to the identifiers.</returns>
        /// <remarks>If an identifier does not match an existing content, it will be missing in the returned value.</remarks>
        public IEnumerable<IPublishedContent> Content(IEnumerable<string> ids) => _publishedContentQuery.Content(ids);

        /// <summary>
        /// Gets the contents corresponding to the identifiers.
        /// </summary>
        /// <param name="ids">The content identifiers.</param>
        /// <returns>The existing contents corresponding to the identifiers.</returns>
        /// <remarks>If an identifier does not match an existing content, it will be missing in the returned value.</remarks>
        public IEnumerable<IPublishedContent> Content(IEnumerable<int> ids) => _publishedContentQuery.Content(ids);

        public IEnumerable<IPublishedContent> ContentAtXPath(string xpath, params XPathVariable[] vars)
        {
            return _publishedContentQuery.ContentAtXPath(xpath, vars);
        }

        public IEnumerable<IPublishedContent> ContentAtXPath(XPathExpression xpath, params XPathVariable[] vars)
        {
            return _publishedContentQuery.ContentAtXPath(xpath, vars);
        }

        public IEnumerable<IPublishedContent> ContentAtRoot()
        {
            return _publishedContentQuery.ContentAtRoot();
        }




        #endregion
        #region Media

        public IPublishedContent Media(Udi id) => _publishedContentQuery.Media(id);

        public IPublishedContent Media(Guid id) => _publishedContentQuery.Media(id);

        /// <summary>
        /// Overloaded method accepting an 'object' type
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        /// <remarks>
        /// We accept an object type because GetPropertyValue now returns an 'object', we still want to allow people to pass
        /// this result in to this method.
        /// This method will throw an exception if the value is not of type int or string.
        /// </remarks>
        public IPublishedContent Media(object id)
        {
            return MediaForObject(id);
        }

        private IPublishedContent MediaForObject(object id) => _publishedContentQuery.Media(id);

        public IPublishedContent Media(int id) => _publishedContentQuery.Media(id);

        public IPublishedContent Media(string id) => _publishedContentQuery.Media(id);

        /// <summary>
        /// Gets the medias corresponding to the identifiers.
        /// </summary>
        /// <param name="ids">The media identifiers.</param>
        /// <returns>The existing medias corresponding to the identifiers.</returns>
        /// <remarks>If an identifier does not match an existing media, it will be missing in the returned value.</remarks>
        public IEnumerable<IPublishedContent> Media(params object[] ids) => _publishedContentQuery.Media(ids);

        private IEnumerable<IPublishedContent> MediaForObjects(IEnumerable<object> ids) => _publishedContentQuery.Media(ids);

        /// <summary>
        /// Gets the medias corresponding to the identifiers.
        /// </summary>
        /// <param name="ids">The media identifiers.</param>
        /// <returns>The existing medias corresponding to the identifiers.</returns>
        /// <remarks>If an identifier does not match an existing media, it will be missing in the returned value.</remarks>
        public IEnumerable<IPublishedContent> Media(params int[] ids) => _publishedContentQuery.Media(ids);

        /// <summary>
        /// Gets the medias corresponding to the identifiers.
        /// </summary>
        /// <param name="ids">The media identifiers.</param>
        /// <returns>The existing medias corresponding to the identifiers.</returns>
        /// <remarks>If an identifier does not match an existing media, it will be missing in the returned value.</remarks>
        public IEnumerable<IPublishedContent> Media(params string[] ids) => _publishedContentQuery.Media(ids);


        /// <summary>
        /// Gets the medias corresponding to the identifiers.
        /// </summary>
        /// <param name="ids">The media identifiers.</param>
        /// <returns>The existing medias corresponding to the identifiers.</returns>
        /// <remarks>If an identifier does not match an existing media, it will be missing in the returned value.</remarks>
        public IEnumerable<IPublishedContent> Media(params Udi[] ids) => _publishedContentQuery.Media(ids);

        /// <summary>
        /// Gets the medias corresponding to the identifiers.
        /// </summary>
        /// <param name="ids">The media identifiers.</param>
        /// <returns>The existing medias corresponding to the identifiers.</returns>
        /// <remarks>If an identifier does not match an existing media, it will be missing in the returned value.</remarks>
        public IEnumerable<IPublishedContent> Media(params GuidUdi[] ids) => _publishedContentQuery.Media(ids);

        /// <summary>
        /// Gets the medias corresponding to the identifiers.
        /// </summary>
        /// <param name="ids">The media identifiers.</param>
        /// <returns>The existing medias corresponding to the identifiers.</returns>
        /// <remarks>If an identifier does not match an existing media, it will be missing in the returned value.</remarks>
        public IEnumerable<IPublishedContent> Media(IEnumerable<object> ids) => _publishedContentQuery.Media(ids);

        /// <summary>
        /// Gets the medias corresponding to the identifiers.
        /// </summary>
        /// <param name="ids">The media identifiers.</param>
        /// <returns>The existing medias corresponding to the identifiers.</returns>
        /// <remarks>If an identifier does not match an existing media, it will be missing in the returned value.</remarks>
        public IEnumerable<IPublishedContent> Media(IEnumerable<int> ids) => _publishedContentQuery.Media(ids);

        /// <summary>
        /// Gets the medias corresponding to the identifiers.
        /// </summary>
        /// <param name="ids">The media identifiers.</param>
        /// <returns>The existing medias corresponding to the identifiers.</returns>
        /// <remarks>If an identifier does not match an existing media, it will be missing in the returned value.</remarks>
        public IEnumerable<IPublishedContent> Media(IEnumerable<Udi> ids) => _publishedContentQuery.Media(ids);

        /// <summary>
        /// Gets the medias corresponding to the identifiers.
        /// </summary>
        /// <param name="ids">The media identifiers.</param>
        /// <returns>The existing medias corresponding to the identifiers.</returns>
        /// <remarks>If an identifier does not match an existing media, it will be missing in the returned value.</remarks>
        public IEnumerable<IPublishedContent> Media(IEnumerable<GuidUdi> ids) => _publishedContentQuery.Media(ids);

        /// <summary>
        /// Gets the medias corresponding to the identifiers.
        /// </summary>
        /// <param name="ids">The media identifiers.</param>
        /// <returns>The existing medias corresponding to the identifiers.</returns>
        /// <remarks>If an identifier does not match an existing media, it will be missing in the returned value.</remarks>
        public IEnumerable<IPublishedContent> Media(IEnumerable<string> ids) => _publishedContentQuery.Media(ids);

        public IEnumerable<IPublishedContent> MediaAtRoot()
        {
            return _publishedContentQuery.MediaAtRoot();
        }

        #endregion
    }
}