// 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.Linq;
using Microsoft.AspNetCore.Mvc.Abstractions;
using Microsoft.AspNetCore.Routing;

namespace Microsoft.AspNetCore.Mvc.ApplicationModels
{
    /// <summary>
    /// A model component for routing RazorPages.
    /// </summary>
    public class PageRouteModel
    {
        /// <summary>
        /// Initializes a new instance of <see cref="PageRouteModel"/>.
        /// </summary>
        /// <param name="relativePath">The application relative path of the page.</param>
        /// <param name="viewEnginePath">The path relative to the base path for page discovery.</param>
        public PageRouteModel(string relativePath, string viewEnginePath)
            : this(relativePath, viewEnginePath, areaName: null)
        {
        }

        /// <summary>
        /// Initializes a new instance of <see cref="PageRouteModel"/>.
        /// </summary>
        /// <param name="relativePath">The application relative path of the page.</param>
        /// <param name="viewEnginePath">The path relative to the base path for page discovery.</param>
        /// <param name="areaName">The area name.</param>
        public PageRouteModel(string relativePath, string viewEnginePath, string areaName)
        {
            RelativePath = relativePath ?? throw new ArgumentNullException(nameof(relativePath));
            ViewEnginePath = viewEnginePath ?? throw new ArgumentNullException(nameof(viewEnginePath));
            AreaName = areaName;

            Properties = new Dictionary<object, object>();
            Selectors = new List<SelectorModel>();
            RouteValues = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
        }

        /// <summary>
        /// A copy constructor for <see cref="PageRouteModel"/>.
        /// </summary>
        /// <param name="other">The <see cref="PageRouteModel"/> to copy from.</param>
        public PageRouteModel(PageRouteModel other)
        {
            if (other == null)
            {
                throw new ArgumentNullException(nameof(other));
            }

            RelativePath = other.RelativePath;
            ViewEnginePath = other.ViewEnginePath;
            AreaName = other.AreaName;

            Properties = new Dictionary<object, object>(other.Properties);
            Selectors = new List<SelectorModel>(other.Selectors.Select(m => new SelectorModel(m)));
            RouteValues = new Dictionary<string, string>(other.RouteValues, StringComparer.OrdinalIgnoreCase);
        }

        /// <summary>
        /// Gets the application root relative path for the page.
        /// </summary>
        public string RelativePath { get; }

        /// <summary>
        /// Gets the path relative to the base path for page discovery.
        /// <para>
        /// This value is the path of the file without extension, relative to the pages root directory.
        /// e.g. the <see cref="ViewEnginePath"/> for the file /Pages/Catalog/Antiques.cshtml is <c>/Catalog/Antiques</c>
        /// </para>
        /// <para>
        /// In an area, this value is the path of the file without extension, relative to the pages root directory for the specified area.
        /// e.g. the <see cref="ViewEnginePath"/>  for the file Areas/Identity/Pages/Manage/Accounts.cshtml, is <c>/Manage/Accounts</c>.
        /// </para>
        /// </summary>
        public string ViewEnginePath { get; }

        /// <summary>
        /// Gets the area name. Will be <c>null</c> for non-area pages.
        /// </summary>
        public string AreaName { get; }

        /// <summary>
        /// Stores arbitrary metadata properties associated with the <see cref="PageRouteModel"/>.
        /// </summary>
        public IDictionary<object, object> Properties { get; }

        /// <summary>
        /// Gets the <see cref="SelectorModel"/> instances.
        /// </summary>
        public IList<SelectorModel> Selectors { get; }

        /// <summary>
        /// Gets a collection of route values that must be present in the <see cref="RouteData.Values"/>
        /// for the corresponding page to be selected.
        /// </summary>
        /// <remarks>
        /// <para>
        /// The value of <see cref="ViewEnginePath"/> is considered an implicit route value corresponding
        /// to the key <c>page</c>.
        /// </para>
        /// <para>
        /// The value of <see cref="AreaName"/> is considered an implicit route value corresponding
        /// to the key <c>area</c> when <see cref="AreaName"/> is not <c>null</c>.
        /// </para>
        /// <para>
        /// These entries will be implicitly added to <see cref="ActionDescriptor.RouteValues"/>
        /// when the action descriptor is created, but will not be visible in <see cref="RouteValues"/>.
        /// </para>
        /// </remarks>
        public IDictionary<string, string> RouteValues { get; }
    }
}