// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Collections.Generic;
using System.Globalization;
using Microsoft.Extensions.Localization;

namespace Microsoft.AspNet.Mvc.Localization
{
    /// <summary>
    /// An <see cref="IHtmlLocalizer"/> that uses the provided <see cref="IStringLocalizer"/> to do HTML-aware
    /// localization of content.
    /// </summary>
    public class HtmlLocalizer : IHtmlLocalizer
    {
        private readonly IStringLocalizer _localizer;

        /// <summary>
        /// Creates a new <see cref="HtmlLocalizer"/>.
        /// </summary>
        /// <param name="localizer">The <see cref="IStringLocalizer"/> to read strings from.</param>
        public HtmlLocalizer(IStringLocalizer localizer)
        {
            if (localizer == null)
            {
                throw new ArgumentNullException(nameof(localizer));
            }

            _localizer = localizer;
        }

        /// <inheritdoc />
        public virtual LocalizedHtmlString this[string name]
        {
            get
            {
                if (name == null)
                {
                    throw new ArgumentNullException(nameof(name));
                }

                return ToHtmlString(_localizer[name]);
            }
        }

        /// <inheritdoc />
        public virtual LocalizedHtmlString this[string name, params object[] arguments]
        {
            get
            {
                if (name == null)
                {
                    throw new ArgumentNullException(nameof(name));
                }

                return ToHtmlString(_localizer[name], arguments);
            }
        }

        /// <inheritdoc />
        public virtual LocalizedString GetString(string name)
        {
            if (name == null)
            {
                throw new ArgumentNullException(nameof(name));
            }

            return _localizer[name];
        }

        /// <inheritdoc />
        public virtual LocalizedString GetString(string name, params object[] arguments)
        {
            if (name == null)
            {
                throw new ArgumentNullException(nameof(name));
            }

            return _localizer[name, arguments];
        }

        /// <inheritdoc />
        public virtual IEnumerable<LocalizedString> GetAllStrings(bool includeParentCultures) =>
            _localizer.GetAllStrings(includeParentCultures);

        /// <inheritdoc />
        public virtual IHtmlLocalizer WithCulture(CultureInfo culture)
        {
            if (culture == null)
            {
                throw new ArgumentNullException(nameof(culture));
            }

            return new HtmlLocalizer(_localizer.WithCulture(culture));
        }

        /// <summary>
        /// Creates a new <see cref="LocalizedHtmlString"/> for a <see cref="LocalizedString"/>.
        /// </summary>
        /// <param name="result">The <see cref="LocalizedString"/>.</param>
        protected virtual LocalizedHtmlString ToHtmlString(LocalizedString result) =>
            new LocalizedHtmlString(result.Name, result.Value, result.ResourceNotFound);

        protected virtual LocalizedHtmlString ToHtmlString(LocalizedString result, object[] arguments) =>
            new LocalizedHtmlString(result.Name, result.Value, result.ResourceNotFound, arguments);
    }
}