// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System;
using Microsoft.Shared.Diagnostics;
 
namespace Microsoft.AspNetCore.HeaderParsing;
 
/// <summary>
/// Stores all setup information for a header.
/// </summary>
/// <typeparam name="THeader">The type of the header value.</typeparam>
public class HeaderSetup<THeader>
    where THeader : notnull
{
    /// <summary>
    /// Gets the name of the header.
    /// </summary>
    public string HeaderName { get; }
 
    /// <summary>
    /// Gets the type of the parser to parse header values.
    /// </summary>
    /// <remarks>Not <see langword="null"/> when <see cref="ParserInstance" /> is <see langword="null"/> and vice versa.</remarks>
    public Type? ParserType { get; }
 
    /// <summary>
    /// Gets the parser to parse header values.
    /// </summary>
    /// <remarks>Not <see langword="null"/> when <see cref="ParserType" /> is <see langword="null"/> and vice versa.</remarks>
    public HeaderParser<THeader>? ParserInstance { get; }
 
    /// <summary>
    /// Gets a value indicating whether this header's parsed values can and/or should be cached.
    /// </summary>
    public bool Cacheable { get; }
 
    /// <summary>
    /// Initializes a new instance of the <see cref="HeaderSetup{THeader}"/> class.
    /// </summary>
    /// <param name="headerName">The name of the header.</param>
    /// <param name="parserType">The type of the parser to parse header values.</param>
    /// <param name="cacheable">Indicates whether the header's values can be cached.</param>
    public HeaderSetup(string headerName, Type parserType, bool cacheable = false)
    {
        HeaderName = Throw.IfNullOrWhitespace(headerName);
        ParserType = Throw.IfNull(parserType);
        Cacheable = cacheable;
    }
 
    /// <summary>
    /// Initializes a new instance of the <see cref="HeaderSetup{THeader}"/> class.
    /// </summary>
    /// <param name="headerName">The name of the header.</param>
    /// <param name="instance">The parser to parse header values.</param>
    /// <param name="cacheable">Indicates whether the header's values can be cached.</param>
    public HeaderSetup(string headerName, HeaderParser<THeader> instance, bool cacheable = false)
    {
        HeaderName = Throw.IfNullOrWhitespace(headerName);
        ParserInstance = Throw.IfNull(instance);
        Cacheable = cacheable;
    }
}