using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Web.Util;

namespace System.Web.UI.WebControls {
    public class DetailsViewRowsGenerator : AutoFieldsGenerator {

        public override List<AutoGeneratedField> CreateAutoGeneratedFields(object dataItem, Control control) {
            if (!(control is DetailsView)) {
                throw new ArgumentException(SR.GetString(SR.InvalidDefaultAutoFieldGenerator, GetType().FullName, typeof(DetailsView).FullName));
            }

            DetailsView detailsView = control as DetailsView;

            if (dataItem == null) {
                // note that we're not throwing an exception in this case, and the calling
                // code should be able to handle a null arraylist being returned
                return null;
            }

            List<AutoGeneratedField> generatedFields = new List<AutoGeneratedField>();
            PropertyDescriptorCollection propDescs = null;
            bool throwException = true;
            Type dataItemType = null;

            //The base class ensures that the AutoGeneratedFieldProperties collection is reset before this method is called.
            //However we are doing this again in here because we have another caller DetailsView.CreateAutoGeneratedRows which is
            //not being used anywhere today but kept for backward compatibility.
            if (AutoGeneratedFieldProperties.Count > 0) {
                AutoGeneratedFieldProperties.Clear();
            }

            if (dataItem != null)
                dataItemType = dataItem.GetType();

            if ((dataItem != null) && (dataItem is ICustomTypeDescriptor)) {
                // Get the custom properties of the object
                propDescs = TypeDescriptor.GetProperties(dataItem);
            }
            else if (dataItemType != null) {
                // directly bindable types: strings, ints etc. get treated specially, since we
                // don't care about their properties, but rather we care about them directly
                if (ShouldGenerateField(dataItemType, detailsView)) {
                    AutoGeneratedFieldProperties fieldProps = new AutoGeneratedFieldProperties();
                    ((IStateManager)fieldProps).TrackViewState();

                    fieldProps.Name = "Item";
                    fieldProps.DataField = AutoGeneratedField.ThisExpression;
                    fieldProps.Type = dataItemType;

                    AutoGeneratedField field = CreateAutoGeneratedFieldFromFieldProperties(fieldProps);
                    if (field != null) {
                        generatedFields.Add(field);
                        AutoGeneratedFieldProperties.Add(fieldProps);
                    }

                }
                else {
                    // complex type... we get its properties
                    propDescs = TypeDescriptor.GetProperties(dataItemType);
                }
            }

            if ((propDescs != null) && (propDescs.Count != 0)) {
                string[] dataKeyNames = detailsView.DataKeyNames;
                int keyNamesLength = dataKeyNames.Length;
                string[] dataKeyNamesCaseInsensitive = new string[keyNamesLength];
                for (int i = 0; i < keyNamesLength; i++) {
                    dataKeyNamesCaseInsensitive[i] = dataKeyNames[i].ToLowerInvariant();
                }
                foreach (PropertyDescriptor pd in propDescs) {
                    Type propertyType = pd.PropertyType;
                    if (ShouldGenerateField(propertyType, detailsView)) {
                        string name = pd.Name;
                        bool isKey = ((IList)dataKeyNamesCaseInsensitive).Contains(name.ToLowerInvariant());
                        AutoGeneratedFieldProperties fieldProps = new AutoGeneratedFieldProperties();
                        ((IStateManager)fieldProps).TrackViewState();

                        fieldProps.Name = name;
                        fieldProps.IsReadOnly = isKey;
                        fieldProps.Type = propertyType;
                        fieldProps.DataField = name;

                        AutoGeneratedField field = CreateAutoGeneratedFieldFromFieldProperties(fieldProps);
                        if (field != null) {
                            generatedFields.Add(field);
                            AutoGeneratedFieldProperties.Add(fieldProps);
                        }
                    }
                }
            }

            if ((generatedFields.Count == 0) && throwException) {
                // this handles the case where we got back something that either had no
                // properties, or all properties were not bindable.
                throw new InvalidOperationException(SR.GetString(SR.DetailsView_NoAutoGenFields, detailsView.ID));
            }

            return generatedFields;
        }

        private bool ShouldGenerateField(Type propertyType, DetailsView detailsView) {
            if (detailsView.RenderingCompatibility < VersionUtil.Framework45 && AutoGenerateEnumFields == null) {
                //This is for backward compatibility. Before 4.5, auto generating fields used to call into this method
                //and if someone has overriden this method to force generation of columns, the scenario should still
                //work.
                return detailsView.IsBindableType(propertyType);
            }
            else {
                //If AutoGenerateEnumFileds is null here, the rendering compatibility must be 4.5
                return DataBoundControlHelper.IsBindableType(propertyType, enableEnums: AutoGenerateEnumFields ?? true);
            }
        }

    }
}