using Microsoft.Extensions.Localization;

namespace Volo.Abp.Localization
{
    /// <summary>
    /// This class is designed to be used internal by the framework.
    /// </summary>
    public static class AbpInternalLocalizationHelper
    {
        /// <summary>
        /// Searches an array of keys in an array of localizers.
        /// </summary>
        /// <param name="localizers">
        /// An array of localizers. Search the keys on the localizers.
        /// Can contain null items in the array.
        /// </param>
        /// <param name="keys">
        /// An array of keys. Search the keys on the localizers.
        /// Should not contain null items in the array.
        /// </param>
        /// <param name="defaultValue">
        /// Return value if none of the localizers has none of the keys.
        /// </param>
        /// <returns></returns>
        public static string LocalizeWithFallback(
            IStringLocalizer[] localizers,
            string[] keys,
            string defaultValue)
        {
            foreach (var key in keys)
            {
                foreach (var localizer in localizers)
                {
                    if (localizer == null)
                    {
                        continue;
                    }

                    var localizedString = localizer[key];
                    if (!localizedString.ResourceNotFound)
                    {
                        return localizedString.Value;
                    }
                }
            }

            return defaultValue;
        }
    }
}