using System;
using System.Linq;
using Microsoft.Extensions.Logging;
using Umbraco.Cms.Core.Mapping;
using Umbraco.Cms.Core.Models.ContentEditing;
using Umbraco.Cms.Core.PropertyEditors;
using Umbraco.Cms.Core.Services;
using Umbraco.Extensions;

namespace Umbraco.Cms.Core.Models.Mapping
{
    /// <summary>
    /// Creates a base generic ContentPropertyBasic from a Property
    /// </summary>
    internal class ContentPropertyBasicMapper<TDestination>
        where TDestination : ContentPropertyBasic, new()
    {
        private readonly IEntityService _entityService;
        private readonly ILogger<ContentPropertyBasicMapper<TDestination>> _logger;
        private readonly PropertyEditorCollection _propertyEditors;
        protected IDataTypeService DataTypeService { get; }

        public ContentPropertyBasicMapper(IDataTypeService dataTypeService, IEntityService entityService, ILogger<ContentPropertyBasicMapper<TDestination>> logger, PropertyEditorCollection propertyEditors)
        {
            _logger = logger;
            _propertyEditors = propertyEditors;
            DataTypeService = dataTypeService;
            _entityService = entityService;
        }

        /// <summary>
        /// Assigns the PropertyEditor, Id, Alias and Value to the property
        /// </summary>
        /// <returns></returns>
        public virtual void Map(IProperty property, TDestination dest, MapperContext context)
        {
            var editor = _propertyEditors[property.PropertyType.PropertyEditorAlias];
            if (editor == null)
            {
                _logger.LogError(
                    new NullReferenceException("The property editor with alias " + property.PropertyType.PropertyEditorAlias + " does not exist"),
                    "No property editor '{PropertyEditorAlias}' found, converting to a Label",
                    property.PropertyType.PropertyEditorAlias);

                editor = _propertyEditors[Constants.PropertyEditors.Aliases.Label];

                if (editor == null)
                    throw new InvalidOperationException($"Could not resolve the property editor {Constants.PropertyEditors.Aliases.Label}");
            }

            dest.Id = property.Id;
            dest.Alias = property.Alias;
            dest.PropertyEditor = editor;
            dest.Editor = editor.Alias;
            dest.DataTypeKey = property.PropertyType.DataTypeKey;

            // if there's a set of property aliases specified, we will check if the current property's value should be mapped.
            // if it isn't one of the ones specified in 'includeProperties', we will just return the result without mapping the Value.
            var includedProperties = context.GetIncludedProperties();
            if (includedProperties != null && !includedProperties.Contains(property.Alias))
                return;

            //Get the culture from the context which will be set during the mapping operation for each property
            var culture = context.GetCulture();

            //a culture needs to be in the context for a property type that can vary
            if (culture == null && property.PropertyType.VariesByCulture())
                throw new InvalidOperationException($"No culture found in mapping operation when one is required for the culture variant property type {property.PropertyType.Alias}");

            //set the culture to null if it's an invariant property type
            culture = !property.PropertyType.VariesByCulture() ? null : culture;

            dest.Culture = culture;

            // Get the segment, which is always allowed to be null even if the propertyType *can* be varied by segment.
            // There is therefore no need to perform the null check like with culture above.
            var segment = !property.PropertyType.VariesBySegment() ? null : context.GetSegment();
            dest.Segment = segment;

            // if no 'IncludeProperties' were specified or this property is set to be included - we will map the value and return.
            dest.Value = editor.GetValueEditor().ToEditor(property, culture, segment);

        }
    }
}