using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
using System.Threading;
using System.Xml.Linq;
using Umbraco.Core.IO;
using Umbraco.Core.Logging;
using Umbraco.Core.Models;
using Umbraco.Core.Persistence;
using Umbraco.Core.Persistence.Querying;
using Umbraco.Core.Persistence.UnitOfWork;

namespace Umbraco.Core.Services
{
    /// <summary>
    /// Represents the Packaging Service, which provides import/export functionality for the Core models of the API
    /// using xml representation. This is primarily used by the Package functionality.
    /// </summary>
    public class PackagingService : IService
    {
        private readonly IContentService _contentService;
        private readonly IContentTypeService _contentTypeService;
        private readonly IMediaService _mediaService;
        private readonly IDataTypeService _dataTypeService;
        private readonly IFileService _fileService;
        private readonly RepositoryFactory _repositoryFactory;
        private readonly IDatabaseUnitOfWorkProvider _uowProvider;
        private Dictionary<string, IContentType> _importedContentTypes;

        //Support recursive locks because some of the methods that require locking call other methods that require locking. 
        //for example, the Move method needs to be locked but this calls the Save method which also needs to be locked.
        private static readonly ReaderWriterLockSlim Locker = new ReaderWriterLockSlim(LockRecursionPolicy.SupportsRecursion);

        public PackagingService(IContentService contentService, IContentTypeService contentTypeService, IMediaService mediaService, IDataTypeService dataTypeService, IFileService fileService, RepositoryFactory repositoryFactory, IDatabaseUnitOfWorkProvider uowProvider)
        {
            _contentService = contentService;
            _contentTypeService = contentTypeService;
            _mediaService = mediaService;
            _dataTypeService = dataTypeService;
            _fileService = fileService;
            _repositoryFactory = repositoryFactory;
            _uowProvider = uowProvider;

            _importedContentTypes = new Dictionary<string, IContentType>();
        }

        #region Content

        /// <summary>
        /// Imports and saves package xml as <see cref="IContent"/>
        /// </summary>
        /// <param name="element">Xml to import</param>
        /// <param name="parentId">Optional parent Id for the content being imported</param>
        /// <param name="userId">Optional Id of the user performing the import</param>
        /// <returns>An enumrable list of generated content</returns>
        public IEnumerable<IContent> ImportContent(XElement element, int parentId = -1, int userId = 0)
        {
            var name = element.Name.LocalName;
            if (name.Equals("DocumentSet"))
            {
                //This is a regular deep-structured import
                var roots = from doc in element.Elements()
                            where (string)doc.Attribute("isDoc") == ""
                            select doc;

                var contents = ParseDocumentRootXml(roots, parentId);
                if(contents.Any())
                    _contentService.Save(contents, userId);

                return contents;
            }

            var attribute = element.Attribute("isDoc");
            if (attribute != null)
            {
                //This is a single doc import
                var elements = new List<XElement> { element };
                var contents = ParseDocumentRootXml(elements, parentId);
                if (contents.Any())
                    _contentService.Save(contents, userId);

                return contents;
            }

            throw new ArgumentException(
                "The passed in XElement is not valid! It does not contain a root element called " +
                "'DocumentSet' (for structured imports) nor is the first element a Document (for single document import).");
        }

        private IEnumerable<IContent> ParseDocumentRootXml(IEnumerable<XElement> roots, int parentId)
        {
            var contents = new List<IContent>();
            foreach (var root in roots)
            {
                bool isLegacySchema = root.Name.LocalName.ToLowerInvariant().Equals("node");
                string contentTypeAlias = isLegacySchema
                                              ? root.Attribute("nodeTypeAlias").Value
                                              : root.Name.LocalName;

                if (_importedContentTypes.ContainsKey(contentTypeAlias) == false)
                {
                    var contentType = FindContentTypeByAlias(contentTypeAlias);
                    _importedContentTypes.Add(contentTypeAlias, contentType);
                }

                var content = CreateContentFromXml(root, _importedContentTypes[contentTypeAlias], null, parentId, isLegacySchema);
                contents.Add(content);

                var children = from child in root.Elements()
                               where (string)child.Attribute("isDoc") == ""
                               select child;
                if (children.Any())
                    contents.AddRange(CreateContentFromXml(children, content, isLegacySchema));
            }
            return contents;
        }

        private IEnumerable<IContent> CreateContentFromXml(IEnumerable<XElement> children, IContent parent, bool isLegacySchema)
        {
            var list = new List<IContent>();
            foreach (var child in children)
            {
                string contentTypeAlias = isLegacySchema
                                              ? child.Attribute("nodeTypeAlias").Value
                                              : child.Name.LocalName;

                if (_importedContentTypes.ContainsKey(contentTypeAlias) == false)
                {
                    var contentType = FindContentTypeByAlias(contentTypeAlias);
                    _importedContentTypes.Add(contentTypeAlias, contentType);
                }

                //Create and add the child to the list
                var content = CreateContentFromXml(child, _importedContentTypes[contentTypeAlias], parent, default(int), isLegacySchema);
                list.Add(content);

                //Recursive call
                XElement child1 = child;
                var grandChildren = from grand in child1.Elements()
                                    where (string)grand.Attribute("isDoc") == ""
                                    select grand;

                if (grandChildren.Any())
                    list.AddRange(CreateContentFromXml(grandChildren, content, isLegacySchema));
            }

            return list;
        }

        private IContent CreateContentFromXml(XElement element, IContentType contentType, IContent parent, int parentId, bool isLegacySchema)
        {
            var id = element.Attribute("id").Value;
            var level = element.Attribute("level").Value;
            var sortOrder = element.Attribute("sortOrder").Value;
            var nodeName = element.Attribute("nodeName").Value;
            var path = element.Attribute("path").Value;
            var template = element.Attribute("template").Value;

            var properties = from property in element.Elements()
                             where property.Attribute("isDoc") == null
                             select property;

            IContent content = parent == null
                                   ? new Content(nodeName, parentId, contentType)
                                   {
                                       Level = int.Parse(level),
                                       SortOrder = int.Parse(sortOrder)
                                   }
                                   : new Content(nodeName, parent, contentType)
                                   {
                                       Level = int.Parse(level),
                                       SortOrder = int.Parse(sortOrder)
                                   };

            foreach (var property in properties)
            {
                string propertyTypeAlias = isLegacySchema ? property.Attribute("alias").Value : property.Name.LocalName;
                if (content.HasProperty(propertyTypeAlias))
                    content.SetValue(propertyTypeAlias, property.Value);
            }

            return content;
        }

        internal XElement Export(IContent content, bool deep = false)
        {
            throw new NotImplementedException();
        }

        #endregion

        #region ContentTypes

        /// <summary>
        /// Imports and saves package xml as <see cref="IContentType"/>
        /// </summary>
        /// <param name="element">Xml to import</param>
        /// <param name="userId">Optional id of the User performing the operation. Default is zero (admin).</param>
        /// <returns>An enumrable list of generated ContentTypes</returns>
        public IEnumerable<IContentType> ImportContentTypes(XElement element, int userId = 0)
        {
            return ImportContentTypes(element, true, userId);
        }

        /// <summary>
        /// Imports and saves package xml as <see cref="IContentType"/>
        /// </summary>
        /// <param name="element">Xml to import</param>
        /// <param name="importStructure">Boolean indicating whether or not to import the </param>
        /// <param name="userId">Optional id of the User performing the operation. Default is zero (admin).</param>
        /// <returns>An enumrable list of generated ContentTypes</returns>
        public IEnumerable<IContentType> ImportContentTypes(XElement element, bool importStructure, int userId = 0)
        {
            var name = element.Name.LocalName;
            if (name.Equals("DocumentTypes") == false && name.Equals("DocumentType") == false)
            {
                throw new ArgumentException("The passed in XElement is not valid! It does not contain a root element called 'DocumentTypes' for multiple imports or 'DocumentType' for a single import.");
            }

            _importedContentTypes = new Dictionary<string, IContentType>();
            var documentTypes = name.Equals("DocumentTypes")
                                    ? (from doc in element.Elements("DocumentType") select doc).ToList()
                                    : new List<XElement> {element};
            //NOTE it might be an idea to sort the doctype XElements based on dependencies
            //before creating the doc types - should also allow for a better structure/inheritance support.
            foreach (var documentType in documentTypes)
            {
                var alias = documentType.Element("Info").Element("Alias").Value;
                if (_importedContentTypes.ContainsKey(alias) == false)
                {
                    var contentType = _contentTypeService.GetContentType(alias);
                    _importedContentTypes.Add(alias, contentType == null
                                                         ? CreateContentTypeFromXml(documentType)
                                                         : UpdateContentTypeFromXml(documentType, contentType));
                }
            }

            var list = _importedContentTypes.Select(x => x.Value).ToList();
            _contentTypeService.Save(list, userId);

            if (importStructure)
            {
                var updatedContentTypes = new List<IContentType>();
                //Update the structure here - we can't do it untill all DocTypes have been created
                foreach (var documentType in documentTypes)
                {
                    var alias = documentType.Element("Info").Element("Alias").Value;
                    var structureElement = documentType.Element("Structure");
                    //Ensure that we only update ContentTypes which has actual structure-elements
                    if (structureElement == null || structureElement.Elements("DocumentType").Any() == false) continue;

                    var updated = UpdateContentTypesStructure(_importedContentTypes[alias], structureElement);
                    updatedContentTypes.Add(updated);
                }
                //Update ContentTypes with a newly added structure/list of allowed children
                if (updatedContentTypes.Any())
                    _contentTypeService.Save(updatedContentTypes, userId);
            }

            return list;
        }

        private IContentType CreateContentTypeFromXml(XElement documentType)
        {
            var infoElement = documentType.Element("Info");

            //Name of the master corresponds to the parent
            var masterElement = infoElement.Element("Master");
            IContentType parent = null;
            if (masterElement != null)
            {
                var masterAlias = masterElement.Value;
                parent = _importedContentTypes.ContainsKey(masterAlias)
                             ? _importedContentTypes[masterAlias]
                             : _contentTypeService.GetContentType(masterAlias);
            }

            var contentType = parent == null
                                  ? new ContentType(-1)
                                        {
                                            Alias = infoElement.Element("Alias").Value
                                        }
                                  : new ContentType(parent)
                                        {
                                            Alias = infoElement.Element("Alias").Value
                                        };

            if (parent != null)
                contentType.AddContentType(parent);

            return UpdateContentTypeFromXml(documentType, contentType);
        }

        private IContentType UpdateContentTypeFromXml(XElement documentType, IContentType contentType)
        {
            var infoElement = documentType.Element("Info");
            var defaultTemplateElement = infoElement.Element("DefaultTemplate");

            contentType.Name = infoElement.Element("Name").Value;
            contentType.Icon = infoElement.Element("Icon").Value;
            contentType.Thumbnail = infoElement.Element("Thumbnail").Value;
            contentType.Description = infoElement.Element("Description").Value;
            //NOTE AllowAtRoot is a new property in the package xml so we need to verify it exists before using it.
            if (infoElement.Element("AllowAtRoot") != null)
                contentType.AllowedAsRoot = infoElement.Element("AllowAtRoot").Value.ToLowerInvariant().Equals("true");

            UpdateContentTypesAllowedTemplates(contentType, infoElement.Element("AllowedTemplates"), defaultTemplateElement);
            UpdateContentTypesTabs(contentType, documentType.Element("Tabs"));
            UpdateContentTypesProperties(contentType, documentType.Element("GenericProperties"));

            return contentType;
        }

        private void UpdateContentTypesAllowedTemplates(IContentType contentType,
                                                        XElement allowedTemplatesElement, XElement defaultTemplateElement)
        {
            if (allowedTemplatesElement != null && allowedTemplatesElement.Elements("Template").Any())
            {
                var allowedTemplates = contentType.AllowedTemplates.ToList();
                foreach (var templateElement in allowedTemplatesElement.Elements("Template"))
                {
                    var alias = templateElement.Value;
                    var template = _fileService.GetTemplate(alias);
                    if (template != null)
                    {
                        allowedTemplates.Add(template);
                    }
                    else
                    {
                        LogHelper.Warn<PackagingService>(
                            string.Format(
                                "Packager: Error handling allowed templates. Template with alias '{0}' could not be found.",
                                alias));
                    }
                }

                contentType.AllowedTemplates = allowedTemplates;
            }

            if (string.IsNullOrEmpty(defaultTemplateElement.Value) == false)
            {
                var defaultTemplate = _fileService.GetTemplate(defaultTemplateElement.Value);
                if (defaultTemplate != null)
                {
                    contentType.SetDefaultTemplate(defaultTemplate);
                }
                else
                {
                    LogHelper.Warn<PackagingService>(
                        string.Format(
                            "Packager: Error handling default template. Default template with alias '{0}' could not be found.",
                            defaultTemplateElement.Value));
                }
            }
        }

        private void UpdateContentTypesTabs(IContentType contentType, XElement tabElement)
        {
            if(tabElement == null)
                return;

            var tabs = tabElement.Elements("Tab");
            foreach (var tab in tabs)
            {
                var id = tab.Element("Id").Value;//Do we need to use this for tracking?
                var caption = tab.Element("Caption").Value;
                if (contentType.PropertyGroups.Contains(caption) == false)
                {
                    contentType.AddPropertyGroup(caption);
                }
            }
        }

        private void UpdateContentTypesProperties(IContentType contentType, XElement genericPropertiesElement)
        {
            var properties = genericPropertiesElement.Elements("GenericProperty");
            foreach (var property in properties)
            {
                var dataTypeId = new Guid(property.Element("Type").Value);//The DataType's Control Id
                var dataTypeDefinitionId = new Guid(property.Element("Definition").Value);//Unique Id for a DataTypeDefinition

                var dataTypeDefinition = _dataTypeService.GetDataTypeDefinitionById(dataTypeDefinitionId);
                //If no DataTypeDefinition with the guid from the xml wasn't found OR the ControlId on the DataTypeDefinition didn't match the DataType Id
                //We look up a DataTypeDefinition that matches
                if (dataTypeDefinition == null || dataTypeDefinition.ControlId != dataTypeId)
                {
                    var dataTypeDefinitions = _dataTypeService.GetDataTypeDefinitionByControlId(dataTypeId);
                    if (dataTypeDefinitions != null && dataTypeDefinitions.Any())
                    {
                        dataTypeDefinition = dataTypeDefinitions.First();
                    }
                }
                
                // For backwards compatibility, if no datatype with that ID can be found, we're letting this fail silently.
                // This means that the property will not be created.
                if(dataTypeDefinition == null)
                {
                    LogHelper.Warn<PackagingService>(string.Format("Packager: Error handling creation of PropertyType '{0}'. Could not find DataTypeDefintion with unique id '{1}' nor one referencing the DataType with control id '{2}'. Did the package creator forget to package up custom datatypes?",
                                                        property.Element("Name").Value, dataTypeDefinitionId, dataTypeId));
                    continue;
                }

                var propertyType = new PropertyType(dataTypeDefinition)
                                       {
                                           Alias = property.Element("Alias").Value, 
                                           Name = property.Element("Name").Value,
                                           Description = property.Element("Description").Value,
                                           Mandatory = property.Element("Mandatory").Value.ToLowerInvariant().Equals("true"),
                                           ValidationRegExp = property.Element("Validation").Value
                                       };

                var helpTextElement = property.Element("HelpText");
                if (helpTextElement != null)
                {
                    propertyType.HelpText = helpTextElement.Value;
                }

                var tab = property.Element("Tab").Value;
                if (string.IsNullOrEmpty(tab))
                {
                    contentType.AddPropertyType(propertyType);
                }
                else
                {
                    contentType.AddPropertyType(propertyType, tab);
                }
            }
        }

        private IContentType UpdateContentTypesStructure(IContentType contentType, XElement structureElement)
        {
            var allowedChildren = contentType.AllowedContentTypes.ToList();
            int sortOrder = allowedChildren.Any() ? allowedChildren.Last().SortOrder : 0;
            foreach (var element in structureElement.Elements("DocumentType"))
            {
                var alias = element.Value;
                if (_importedContentTypes.ContainsKey(alias))
                {
                    var allowedChild = _importedContentTypes[alias];
                    if (allowedChild == null || allowedChildren.Any(x => x.Id.IsValueCreated && x.Id.Value == allowedChild.Id)) continue;

                    allowedChildren.Add(new ContentTypeSort(new Lazy<int>(() => allowedChild.Id), sortOrder, allowedChild.Alias));
                    sortOrder++;
                }
                else
                {
                    LogHelper.Warn<PackagingService>(
                    string.Format(
                        "Packager: Error handling DocumentType structure. DocumentType with alias '{0}' could not be found and was not added to the structure for '{1}'.",
                        alias, contentType.Alias));
                }
            }

            contentType.AllowedContentTypes = allowedChildren;
            return contentType;
        }

        private IContentType FindContentTypeByAlias(string contentTypeAlias)
        {
            using (var repository = _repositoryFactory.CreateContentTypeRepository(_uowProvider.GetUnitOfWork()))
            {
                var query = Query<IContentType>.Builder.Where(x => x.Alias == contentTypeAlias);
                var types = repository.GetByQuery(query);

                if (!types.Any())
                    throw new Exception(
                        string.Format("No ContentType matching the passed in Alias: '{0}' was found",
                                      contentTypeAlias));

                var contentType = types.First();

                if (contentType == null)
                    throw new Exception(string.Format("ContentType matching the passed in Alias: '{0}' was null",
                                                      contentTypeAlias));

                return contentType;
            }
        }

        #endregion

        #region DataTypes

        /// <summary>
        /// Imports and saves package xml as <see cref="IDataTypeDefinition"/>
        /// </summary>
        /// <param name="element">Xml to import</param>
        /// <param name="userId"></param>
        /// <returns>An enumrable list of generated DataTypeDefinitions</returns>
        public IEnumerable<IDataTypeDefinition> ImportDataTypeDefinitions(XElement element, int userId = 0)
        {
            var name = element.Name.LocalName;
            if (name.Equals("DataTypes") == false && name.Equals("DataType") == false)
            {
                throw new ArgumentException("The passed in XElement is not valid! It does not contain a root element called 'DataTypes' for multiple imports or 'DataType' for a single import.");
            }

            var dataTypes = new Dictionary<string, IDataTypeDefinition>();
            var dataTypeElements = name.Equals("DataTypes")
                                       ? (from doc in element.Elements("DataType") select doc).ToList()
                                       : new List<XElement> {element.Element("DataType")};

            foreach (var dataTypeElement in dataTypeElements)
            {
                var dataTypeDefinitionName = dataTypeElement.Attribute("Name").Value;
                var dataTypeId = new Guid(dataTypeElement.Attribute("Id").Value);
                var dataTypeDefinitionId = new Guid(dataTypeElement.Attribute("Definition").Value);
                var databaseTypeAttribute = dataTypeElement.Attribute("DatabaseType");

                var definition = _dataTypeService.GetDataTypeDefinitionById(dataTypeDefinitionId);
                //If the datatypedefinition doesn't already exist we create a new new according to the one in the package xml
                if (definition == null)
                {
                    var databaseType = databaseTypeAttribute != null
                                           ? databaseTypeAttribute.Value.EnumParse<DataTypeDatabaseType>(true)
                                           : DataTypeDatabaseType.Ntext;
                    var dataTypeDefinition = new DataTypeDefinition(-1, dataTypeId)
                                                 {
                                                     Key = dataTypeDefinitionId,
                                                     Name = dataTypeDefinitionName,
                                                     DatabaseType = databaseType
                                                 };
                    dataTypes.Add(dataTypeDefinitionName, dataTypeDefinition);
                }
            }

            var list = dataTypes.Select(x => x.Value).ToList();
            if (list.Any())
            {
                _dataTypeService.Save(list, userId);

                SavePrevaluesFromXml(list, dataTypeElements);
            }
            return list;
        }

        private void SavePrevaluesFromXml(List<IDataTypeDefinition> dataTypes, IEnumerable<XElement> dataTypeElements)
        {
            foreach (var dataTypeElement in dataTypeElements)
            {
                var prevaluesElement = dataTypeElement.Element("PreValues");
                if (prevaluesElement == null) continue;

                var dataTypeDefinitionName = dataTypeElement.Attribute("Name").Value;
                var dataTypeDefinition = dataTypes.First(x => x.Name == dataTypeDefinitionName);

                var values = prevaluesElement.Elements("PreValue").Select(prevalue => prevalue.Attribute("Value").Value).ToList();
                _dataTypeService.SavePreValues(dataTypeDefinition.Id, values);
            }
        }
        #endregion

        #region Dictionary Items
        #endregion

        #region Files
        #endregion

        #region Languages
        #endregion

        #region Macros
        #endregion

        #region Media
        #endregion

        #region MediaTypes
        #endregion

        #region Package Manifest
        #endregion

        #region Templates

        /// <summary>
        /// Imports and saves package xml as <see cref="ITemplate"/>
        /// </summary>
        /// <param name="element">Xml to import</param>
        /// <param name="userId">Optional user id</param>
        /// <returns>An enumrable list of generated Templates</returns>
        public IEnumerable<ITemplate> ImportTemplates(XElement element, int userId = 0)
        {
            var name = element.Name.LocalName;
            if (name.Equals("Templates") == false && name.Equals("Template") == false)
            {
                throw new ArgumentException("The passed in XElement is not valid! It does not contain a root element called 'Templates' for multiple imports or 'Template' for a single import.");
            }

            var templates = new List<ITemplate>();
            var templateElements = name.Equals("Templates")
                                       ? (from doc in element.Elements("Template") select doc).ToList()
                                       : new List<XElement> { element.Element("Template") };

            var fields = new List<TopologicalSorter.DependencyField<XElement>>();
            foreach (XElement tempElement in templateElements)
            {
                var dependencies = new List<string>();
                var elementCopy = tempElement;

                if (elementCopy.Element("Master") != null &&
                    string.IsNullOrEmpty(elementCopy.Element("Master").Value) == false &&
                    templateElements.Any(x => x.Element("Alias").Value == elementCopy.Element("Master").Value))
                {
                    dependencies.Add(elementCopy.Element("Master").Value);
                }
                else if (elementCopy.Element("Master") != null &&
                         string.IsNullOrEmpty(elementCopy.Element("Master").Value) == false &&
                         templateElements.Any(x => x.Element("Alias").Value == elementCopy.Element("Master").Value) ==
                         false)
                {
                    LogHelper.Info<PackagingService>(string.Format("Template '{0}' has an invalid Master '{1}', so the reference has been ignored.", elementCopy.Element("Alias").Value, elementCopy.Element("Master").Value));
                }

                var field = new TopologicalSorter.DependencyField<XElement>
                                {
                                    Alias = elementCopy.Element("Alias").Value,
                                    Item = new Lazy<XElement>(() => elementCopy),
                                    DependsOn = dependencies.ToArray()
                                };

                fields.Add(field);
            }
            //Sort templates by dependencies to a potential master template
            var sortedElements = TopologicalSorter.GetSortedItems(fields);
            foreach (var templateElement in sortedElements)
            {
                var templateName = templateElement.Element("Name").Value;
                var alias = templateElement.Element("Alias").Value;
                var design = templateElement.Element("Design").Value;
                var masterElement = templateElement.Element("Master");

                var isMasterPage = IsMasterPageSyntax(design);
                var path = isMasterPage ? MasterpagePath(alias) : ViewPath(alias);

                var template = new Template(path, templateName, alias) { Content = design };
                if (masterElement != null && string.IsNullOrEmpty(masterElement.Value) == false)
                {
                    template.MasterTemplateAlias = masterElement.Value;
                    var masterTemplate = templates.FirstOrDefault(x => x.Alias == masterElement.Value);
                    if(masterTemplate != null)
                        template.MasterTemplateId = new Lazy<int>(() => masterTemplate.Id);
                }
                templates.Add(template);
            }

            if(templates.Any())
                _fileService.SaveTemplate(templates, userId);

            return templates;
        }

        private bool IsMasterPageSyntax(string code)
        {
            return Regex.IsMatch(code, @"<%@\s*Master", RegexOptions.IgnoreCase) ||
                code.InvariantContains("<umbraco:Item") || code.InvariantContains("<asp:") || code.InvariantContains("<umbraco:Macro");
        }

        private string ViewPath(string alias)
        {
            return SystemDirectories.MvcViews + "/" + alias.Replace(" ", "") + ".cshtml";
        }

        private string MasterpagePath(string alias)
        {
            return IOHelper.MapPath(SystemDirectories.Masterpages + "/" + alias.Replace(" ", "") + ".master");
        }

        #endregion
    }
}