using System;
using System.Collections.Generic;
using System.Xml.Linq;
using System.Xml.XPath;

namespace Neo.Afx.ComponentModel
{
    public static partial class Extensions
    {
        #region Child

        /// <summary>
        /// Gets the child element with the given local name ignoring namespaces that may exist.
        /// </summary>
        /// <param name="e">The container to be queried.</param>
        /// <param name="localName">The local name of the child to be retrieved.</param>
        /// <returns>The child element with the given local name</returns>
        public static XElement Child(this XContainer e, string localName)
        {
            return e.XPathSelectElement(string.Format("./*[local-name()='{0}']", localName));
        }

        #endregion

        #region Children

        /// <summary>
        /// Gets the children with the given local name ignoring namespaces that may exist.
        /// </summary>
        /// <param name="e">The container to be queried.</param>
        /// <param name="localName">The local name of the children to be retrieved.</param>
        /// <returns>The children with the given local name</returns>
        public static IEnumerable<XElement> Children(this XContainer e, string localName)
        {
            return e.XPathSelectElements(string.Format("//*[local-name()='{0}']", localName));
        }

        #endregion

        #region ToBoolean

        /// <summary>
        /// Returns the element value as a boolean.
        /// </summary>
        /// <param name="e">The element to be queried.</param>
        /// <param name="defaultValue">The default value if the attribute is not found.</param>
        /// <returns>The string representation of the element value as a boolean.</returns>
        public static bool ToBoolean(this XElement e, bool defaultValue)
        {
            return ToBoolean(e, string.Empty, false);
        }

        /// <summary>
        /// Returns the attribute value if <paramref name="attributeName"/> is given otherwise the element value as a boolean.
        /// </summary>
        /// <param name="e">The element to be queried.</param>
        /// <param name="attributeName">The name of the attribute to be retrieved.</param>
        /// <param name="defaultValue">The default value if the attribute is not found.</param>
        /// <returns>The string representation of the attribute value if <paramref name="attributeName"/> is given 
        /// otherwise the element value as a boolean.</returns>
        public static bool ToBoolean(this XElement e, string attributeName, bool defaultValue)
        {
            if(e == null)
            {
                return defaultValue;
            }

            var value = string.Empty;
            if(string.IsNullOrEmpty(attributeName))
            {
                value = e.Value;
            }

            var attr = e.Attribute(attributeName);
            if(attr != null)
            {
                value = attr.Value;
            }

            bool result;
            return bool.TryParse(value, out result) ? result : defaultValue;
        }

        #endregion

        #region ToString

        /// <summary>
        /// Returns the element value.
        /// </summary>
        /// <param name="e">The element to be queried.</param>
        /// <param name="defaultValue">The default value if the attribute is not found.</param>
        /// <returns>The string representation of the element value.</returns>
        public static string ToString(this XElement e, string defaultValue)
        {
            return ToString(e, null, defaultValue);
        }


        /// <summary>
        /// Returns the attribute value if <paramref name="attributeName"/> is given otherwise the element value.
        /// </summary>
        /// <param name="e">The element to be queried.</param>
        /// <param name="attributeName">The name of the attribute to be retrieved.</param>
        /// <param name="defaultValue">The default value if the attribute is not found.</param>
        /// <returns>The string representation of the attribute value if <paramref name="attributeName"/> is given 
        /// otherwise the element value.</returns>
        public static string ToString(this XElement e, string attributeName, string defaultValue)
        {
            if(e == null)
            {
                return defaultValue;
            }
            if(string.IsNullOrEmpty(attributeName))
            {
                return e.Value;
            }
            var attr = e.Attribute(attributeName);
            return attr != null ? attr.Value : defaultValue;
        }

        #endregion
    }
}