using System;
using System.Collections.Generic;
using System.Diagnostics;
using Umbraco.Core;
using Umbraco.Core.Models.PublishedContent;
using Umbraco.Core.PropertyEditors.ValueConverters;

namespace Umbraco.Web.Models
{
    /// <summary>
    /// Provide an abstract base class for <c>IPublishedContent</c> implementations.
    /// </summary>
    /// <remarks>This base class does which (a) consistently resolves and caches the Url, (b) provides an implementation
    /// for this[alias], and (c) provides basic content set management.</remarks>
    [DebuggerDisplay("Content Id: {Id}, Name: {Name}")]
    public abstract class PublishedContentBase : IPublishedContent
    {
        protected PublishedContentBase(IUmbracoContextAccessor umbracoContextAccessor)
        {
            UmbracoContextAccessor = umbracoContextAccessor ?? throw new ArgumentNullException(nameof(umbracoContextAccessor));
        }

        protected IUmbracoContextAccessor UmbracoContextAccessor { get; }

        #region ContentType

        public abstract IPublishedContentType ContentType { get; }

        #endregion

        #region PublishedElement

        /// <inheritdoc />
        public abstract Guid Key { get; }

        #endregion

        #region PublishedContent

        /// <inheritdoc />
        public abstract int Id { get; }

        /// <inheritdoc />
        public abstract string Name(string culture = null);

        /// <inheritdoc />
        public abstract string UrlSegment(string culture = null);

        /// <inheritdoc />
        public abstract int SortOrder { get; }

        /// <inheritdoc />
        public abstract int Level { get; }

        /// <inheritdoc />
        public abstract string Path { get; }

        /// <inheritdoc />
        public abstract int? TemplateId { get; }

        /// <inheritdoc />
        public abstract int CreatorId { get; }

        /// <inheritdoc />
        public abstract string CreatorName { get; }

        /// <inheritdoc />
        public abstract DateTime CreateDate { get; }

        /// <inheritdoc />
        public abstract int WriterId { get; }

        /// <inheritdoc />
        public abstract string WriterName { get; }

        /// <inheritdoc />
        public abstract DateTime UpdateDate { get; }

        /// <inheritdoc />
        /// <remarks>
        /// The url of documents are computed by the document url providers. The url of medias are, at the moment,
        /// computed here from the 'umbracoFile' property -- but we should move to media url providers at some point.
        /// </remarks>
        public virtual string Url(string culture = null, UrlMode mode = UrlMode.Auto)
        {
            switch (ContentType.ItemType)
            {
                case PublishedItemType.Content:
                    var umbracoContext = UmbracoContextAccessor.UmbracoContext;

                    if (umbracoContext == null)
                        throw new InvalidOperationException("Cannot compute Url for a content item when UmbracoContext is null.");
                    if (umbracoContext.UrlProvider == null)
                        throw new InvalidOperationException("Cannot compute Url for a content item when UmbracoContext.UrlProvider is null.");

                    return umbracoContext.UrlProvider.GetUrl(this, mode, culture);

                case PublishedItemType.Media:
                    if (mode == UrlMode.Absolute)
                        throw new NotSupportedException("Absolute urls are not supported for media items.");

                    var prop = GetProperty(Constants.Conventions.Media.File);
                    if (prop?.GetValue() == null)
                    {
                        return string.Empty;
                    }

                    var propType = ContentType.GetPropertyType(Constants.Conventions.Media.File);

                    // TODO: consider implementing media url providers
                    // note: that one does not support variations
                    //This is a hack - since we now have 2 properties that support a URL: upload and cropper, we need to detect this since we always
                    // want to return the normal URL and the cropper stores data as json
                    switch (propType.EditorAlias)
                    {
                        case Constants.PropertyEditors.Aliases.UploadField:

                            return prop.GetValue().ToString();
                        case Constants.PropertyEditors.Aliases.ImageCropper:
                            //get the url from the json format

                            var stronglyTyped = prop.GetValue() as ImageCropperValue;
                            if (stronglyTyped != null)
                            {
                                return stronglyTyped.Src;
                            }
                            return prop.GetValue()?.ToString();
                    }

                    return string.Empty;

                default:
                    throw new NotSupportedException();
            }
        }

        /// <inheritdoc />
        public abstract DateTime CultureDate(string culture = null);

        /// <inheritdoc />
        public abstract IReadOnlyList<string> Cultures { get; }

        /// <inheritdoc />
        public abstract bool IsDraft(string culture = null);

        /// <inheritdoc />
        public abstract bool IsPublished(string culture = null);

        #endregion

        #region Tree

        /// <inheritdoc />
        public abstract IPublishedContent Parent();

        /// <inheritdoc />
        public abstract IEnumerable<IPublishedContent> Children { get; }

        #endregion

        #region Properties

        /// <inheritdoc cref="IPublishedElement.Properties"/>
        public abstract IEnumerable<IPublishedProperty> Properties { get; }

        /// <inheritdoc cref="IPublishedElement.GetProperty(string)"/>
        public abstract IPublishedProperty GetProperty(string alias);

        #endregion
    }
}