using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using Umbraco.Core;
using Umbraco.Core.Models.PublishedContent;
using Umbraco.Core.Services;
using Umbraco.Web.BackOffice.Filters;
using Umbraco.Web.Common.Attributes;
using Umbraco.Web.Models.TemplateQuery;

namespace Umbraco.Web.BackOffice.Controllers
{
    /// <summary>
    /// The API controller used for building content queries within the template
    /// </summary>
    [PluginController(Constants.Web.Mvc.BackOfficeApiArea)]
    [JsonCamelCaseFormatter]
    public class TemplateQueryController : UmbracoAuthorizedJsonController
    {
        private readonly IVariationContextAccessor _variationContextAccessor;
        private readonly IPublishedContentQuery _publishedContentQuery;
        private readonly ILocalizedTextService _localizedTextService;
        private readonly IPublishedValueFallback _publishedValueFallback;
        private readonly IContentTypeService _contentTypeService;

        public TemplateQueryController(
            IVariationContextAccessor variationContextAccessor,
            IPublishedContentQuery publishedContentQuery,
            ILocalizedTextService localizedTextService,
            IPublishedValueFallback publishedValueFallback,
            IContentTypeService contentTypeService)
        {
            _variationContextAccessor = variationContextAccessor ??
                                        throw new ArgumentNullException(nameof(variationContextAccessor));
            _publishedContentQuery =
                publishedContentQuery ?? throw new ArgumentNullException(nameof(publishedContentQuery));
            _localizedTextService =
                localizedTextService ?? throw new ArgumentNullException(nameof(localizedTextService));
            _publishedValueFallback =
                publishedValueFallback ?? throw new ArgumentNullException(nameof(publishedValueFallback));
            _contentTypeService = contentTypeService ?? throw new ArgumentNullException(nameof(contentTypeService));
        }

        private IEnumerable<OperatorTerm> Terms => new List<OperatorTerm>
        {
                new OperatorTerm(_localizedTextService.Localize("template/is"), Operator.Equals, new [] {"string"}),
                new OperatorTerm(_localizedTextService.Localize("template/isNot"), Operator.NotEquals, new [] {"string"}),
                new OperatorTerm(_localizedTextService.Localize("template/before"), Operator.LessThan, new [] {"datetime"}),
                new OperatorTerm(_localizedTextService.Localize("template/beforeIncDate"), Operator.LessThanEqualTo, new [] {"datetime"}),
                new OperatorTerm(_localizedTextService.Localize("template/after"), Operator.GreaterThan, new [] {"datetime"}),
                new OperatorTerm(_localizedTextService.Localize("template/afterIncDate"), Operator.GreaterThanEqualTo, new [] {"datetime"}),
                new OperatorTerm(_localizedTextService.Localize("template/equals"), Operator.Equals, new [] {"int"}),
                new OperatorTerm(_localizedTextService.Localize("template/doesNotEqual"), Operator.NotEquals, new [] {"int"}),
                new OperatorTerm(_localizedTextService.Localize("template/contains"), Operator.Contains, new [] {"string"}),
                new OperatorTerm(_localizedTextService.Localize("template/doesNotContain"), Operator.NotContains, new [] {"string"}),
                new OperatorTerm(_localizedTextService.Localize("template/greaterThan"), Operator.GreaterThan, new [] {"int"}),
                new OperatorTerm(_localizedTextService.Localize("template/greaterThanEqual"), Operator.GreaterThanEqualTo, new [] {"int"}),
                new OperatorTerm(_localizedTextService.Localize("template/lessThan"), Operator.LessThan, new [] {"int"}),
                new OperatorTerm(_localizedTextService.Localize("template/lessThanEqual"), Operator.LessThanEqualTo, new [] {"int"})
            };

        private IEnumerable<PropertyModel> Properties => new List<PropertyModel>
            {
                new PropertyModel { Name = _localizedTextService.Localize("template/id"), Alias = "Id", Type = "int" },
                new PropertyModel { Name = _localizedTextService.Localize("template/name"), Alias = "Name", Type = "string" },
                new PropertyModel { Name = _localizedTextService.Localize("template/createdDate"), Alias = "CreateDate", Type = "datetime" },
                new PropertyModel { Name = _localizedTextService.Localize("template/lastUpdatedDate"), Alias = "UpdateDate", Type = "datetime" }
            };

        public QueryResultModel PostTemplateQuery(QueryModel model)
        {
            var queryExpression = new StringBuilder();
            IEnumerable<IPublishedContent> contents;

            if (model == null)
            {
                contents = _publishedContentQuery.ContentAtRoot().FirstOrDefault().Children(_variationContextAccessor);
                queryExpression.Append("Umbraco.ContentAtRoot().FirstOrDefault().Children()");
            }
            else
            {
                contents = PostTemplateValue(model, queryExpression);
            }

            // timing should be fairly correct, due to the fact that all the linq statements are yield returned.
            var timer = new Stopwatch();
            timer.Start();
            var results = contents.ToList();
            timer.Stop();

            return new QueryResultModel
            {
                QueryExpression = queryExpression.ToString(),
                ResultCount = results.Count,
                ExecutionTime = timer.ElapsedMilliseconds,
                SampleResults = results.Take(20).Select(x => new TemplateQueryResult
                {
                    Icon = "icon-document",
                    Name = x.Name
                })
            };
        }

        private IEnumerable<IPublishedContent> PostTemplateValue(QueryModel model, StringBuilder queryExpression)
        {
            var indent = Environment.NewLine + "    ";

            // set the source
            IPublishedContent sourceDocument;
            if (model.Source != null && model.Source.Id > 0)
            {
                sourceDocument = _publishedContentQuery.Content(model.Source.Id);

                if (sourceDocument == null)
                    queryExpression.AppendFormat("Umbraco.Content({0})", model.Source.Id);
                else
                    queryExpression.AppendFormat("Umbraco.Content(Guid.Parse(\"{0}\"))", sourceDocument.Key);
            }
            else
            {
                sourceDocument = _publishedContentQuery.ContentAtRoot().FirstOrDefault();
                queryExpression.Append("Umbraco.ContentAtRoot().FirstOrDefault()");
            }

            // get children, optionally filtered by type
            IEnumerable<IPublishedContent> contents;
            queryExpression.Append(indent);
            if (model.ContentType != null && !model.ContentType.Alias.IsNullOrWhiteSpace())
            {
                contents = sourceDocument == null
                    ? Enumerable.Empty<IPublishedContent>()
                    : sourceDocument.ChildrenOfType(_variationContextAccessor, model.ContentType.Alias);
                queryExpression.AppendFormat(".ChildrenOfType(\"{0}\")", model.ContentType.Alias);
            }
            else
            {
                contents = sourceDocument == null
                    ? Enumerable.Empty<IPublishedContent>()
                    : sourceDocument.Children(_variationContextAccessor);
                queryExpression.Append(".Children()");
            }

            // apply filters
            foreach (var condition in model.Filters.Where(x => !x.ConstraintValue.IsNullOrWhiteSpace()))
            {
                //x is passed in as the parameter alias for the linq where statement clause
                var operation = condition.BuildCondition<IPublishedContent>("x");

                    //for review - this uses a tonized query rather then the normal linq query.
                contents = contents.Where(operation.Compile());
                queryExpression.Append(indent);
                queryExpression.AppendFormat(".Where({0})", operation);
            }

            // always add IsVisible() to the query
            contents = contents.Where(x => x.IsVisible(_publishedValueFallback));
            queryExpression.Append(indent);
            queryExpression.Append(".Where(x => x.IsVisible())");

            // apply sort
            if (model.Sort != null && !model.Sort.Property.Alias.IsNullOrWhiteSpace())
            {
                contents = SortByDefaultPropertyValue(contents, model.Sort);

                queryExpression.Append(indent);
                queryExpression.AppendFormat(model.Sort.Direction == "ascending"
                    ? ".OrderBy(x => x.{0})"
                    : ".OrderByDescending(x => x.{0})"
                    , model.Sort.Property.Alias);
            }

            // take
            if (model.Take > 0)
            {
                contents = contents.Take(model.Take);
                queryExpression.Append(indent);
                queryExpression.AppendFormat(".Take({0})", model.Take);
            }

            return contents;
        }

        private object GetConstraintValue(QueryCondition condition)
        {
            switch (condition.Property.Type)
            {
                case "int":
                    return int.Parse(condition.ConstraintValue);
                case "datetime":
                    DateTime dt;
                    return DateTime.TryParse(condition.ConstraintValue, out dt) ? dt : DateTime.Today;
                default:
                    return condition.ConstraintValue;
            }
        }

        private IEnumerable<IPublishedContent> SortByDefaultPropertyValue(IEnumerable<IPublishedContent> contents, SortExpression sortExpression)
        {
            switch (sortExpression.Property.Alias)
            {
                case "id":
                    return sortExpression.Direction == "ascending"
                        ? contents.OrderBy(x => x.Id)
                        : contents.OrderByDescending(x => x.Id);
                case "createDate":
                    return sortExpression.Direction == "ascending"
                        ? contents.OrderBy(x => x.CreateDate)
                        : contents.OrderByDescending(x => x.CreateDate);
                case "publishDate":
                    return sortExpression.Direction == "ascending"
                        ? contents.OrderBy(x => x.UpdateDate)
                        : contents.OrderByDescending(x => x.UpdateDate);
                case "name":
                    return sortExpression.Direction == "ascending"
                        ? contents.OrderBy(x => x.Name)
                        : contents.OrderByDescending(x => x.Name);
                default:
                    return sortExpression.Direction == "ascending"
                        ? contents.OrderBy(x => x.Name)
                        : contents.OrderByDescending(x => x.Name);
            }
        }

        /// <summary>
        /// Gets a list of all content types
        /// </summary>
        /// <returns></returns>
        public IEnumerable<ContentTypeModel> GetContentTypes()
        {
            var contentTypes = _contentTypeService.GetAll()
                .Select(x => new ContentTypeModel { Alias = x.Alias, Name = _localizedTextService.Localize("template/contentOfType", tokens: new string[] { x.Name }) })
                .OrderBy(x => x.Name).ToList();

            contentTypes.Insert(0, new ContentTypeModel { Alias = string.Empty, Name = _localizedTextService.Localize("template/allContent") });

            return contentTypes;
        }

        /// <summary>
        /// Returns a collection of allowed properties.
        /// </summary>
        public IEnumerable<PropertyModel> GetAllowedProperties()
        {
            return Properties.OrderBy(x => x.Name);
        }

        /// <summary>
        /// Returns a collection of constraint conditions that can be used in the query
        /// </summary>
        public IEnumerable<object> GetFilterConditions()
        {
            return Terms;
        }
    }
}