C.B.R.

using System;
using System.Globalization;
using System.Windows.Markup;

namespace CBR.Core.Helpers.Localization
{
    /// <summary>
    /// Defines the handling method for the <see cref="ResxExtension.GetResource"/> event
    /// </summary>
    /// <param name="resxName">The name of the resx file</param>
    /// <param name="key">The resource key within the file</param>
    /// <param name="culture">The culture to get the resource for</param>
    /// <returns>The resource</returns>
    public delegate object GetResourceHandler(string resxName, string key, CultureInfo culture);

    /// <summary>
    /// A markup extension to allow resources for WPF Windows and controls to be retrieved
    /// from a resource file associated with the window or control
    /// </summary>
    [MarkupExtensionReturnType(typeof(object))]
    public class LocalizationExtension : ManagedMarkupExtension
    {
        #region ----------------PROPERTIES----------------

        /// <summary>
        /// The type name that the resource is associated with
        /// </summary>
        private string _resModul;

        /// <summary>
        /// The fully qualified name of the embedded resx (without .resources) to get the resource from
        /// </summary>
        public string ResModul
        {
            get { return _resModul; }
            set { _resModul = value; }
        }

        /// <summary>
        /// The key used to retrieve the resource
        /// </summary>
        private string _key;

        /// <summary>
        /// The name of the resource key
        /// </summary>
        public string Key
        {
            get { return _key; }
            set { _key = value; }
        }

        /// <summary>
        /// The default value for the property
        /// </summary>
        private string _defaultValue;

        /// <summary>
        /// The default value to use if the resource can't be found
        /// </summary>
        /// <remarks>
        /// This particularly useful for properties which require non-null
        /// values because it allows the page to be displayed even if the resource can't be loaded
        /// </remarks>
        public string DefaultValue
        {
            get { return _defaultValue; }
            set { _defaultValue = value; }
        }

        #endregion

        #region ----------------EVENTS----------------

        /// <summary>
        /// This event allows a designer or preview application (such as Globalizer.NET) to
        /// intercept calls to get resources and provide the values instead dynamically
        /// </summary>
        public static event GetResourceHandler GetResource;

        #endregion

        #region ----------------CONSTRUCTORS----------------

        /// <summary>
        /// Create a new instance of the markup extension
        /// </summary>
        public LocalizationExtension() : base()
        {
        }

        /// <summary>
        /// Create a new instance of the markup extension
        /// </summary>
        /// <param name="resxName">The fully qualified name of the embedded resx (without .resources)</param>
        /// <param name="key">The key used to get the value from the resources</param>
        /// <param name="defaultValue">
        /// The default value for the property (can be null).  This is useful for non-string
        /// that properties that may otherwise cause page load errors if the resource is not
        /// present for some reason (eg at design time before the assembly has been compiled)
        /// </param>
        public LocalizationExtension(string key, string defaultValue)
            : base()
        {
            this._key = key;
            if (!string.IsNullOrEmpty(defaultValue))
            {
                this._defaultValue = defaultValue;
            }
        }

        #endregion

        #region ----------------MARKUP EXTENSION OVERRIDE----------------

        /// <summary>
        /// Return the value associated with the key from the resource manager
        /// </summary>
        /// <returns>The value from the resources if possible otherwise the default value</returns>
        protected override object GetValue()
        {
            if (string.IsNullOrEmpty(Key))
                throw new ArgumentException("Key cannot be null");

            object result = null;
            IResourceProvider provider = null;

            try
            {
                object resource = null;

                //allow resource trapping by calling the handler
                if (GetResource != null)
                    resource = GetResource(ResModul, Key, CultureManager.Instance.UICulture);

                if (resource == null)
                {
                    //get the provider
                    if (provider == null)
                        provider = CultureManager.Instance.Provider;

                    //get the localized resource
                    if (provider != null)
                        resource = provider.GetObject(this, CultureManager.Instance.UICulture);
                }

                //and then convert it to desired type
                result = provider.ConvertValue(this, resource);
            }
            catch (Exception err)
            {
            }
            try
            {
                // if it does not work, we ask the default value
                if (result == null)
                    result = provider.GetDefaultValue(this, CultureManager.Instance.UICulture);
            }
            catch (Exception err)
            {
            }

            return result;
        }

        #endregion
    }
}