// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Diagnostics;
using Microsoft.AspNetCore.Routing.Patterns;
 
namespace Microsoft.AspNetCore.Routing;
 
/// <summary>
/// Defines an abstraction for resolving inline parameter policies as instances of <see cref="IParameterPolicy"/>.
/// </summary>
public abstract class ParameterPolicyFactory
{
    /// <summary>
    /// Creates a parameter policy.
    /// </summary>
    /// <param name="parameter">The parameter the parameter policy is being created for.</param>
    /// <param name="inlineText">The inline text to resolve.</param>
    /// <returns>The <see cref="IParameterPolicy"/> for the parameter.</returns>
    public abstract IParameterPolicy Create(RoutePatternParameterPart? parameter, string inlineText);
 
    /// <summary>
    /// Creates a parameter policy.
    /// </summary>
    /// <param name="parameter">The parameter the parameter policy is being created for.</param>
    /// <param name="parameterPolicy">An existing parameter policy.</param>
    /// <returns>The <see cref="IParameterPolicy"/> for the parameter.</returns>
    public abstract IParameterPolicy Create(RoutePatternParameterPart? parameter, IParameterPolicy parameterPolicy);
 
    /// <summary>
    /// Creates a parameter policy.
    /// </summary>
    /// <param name="parameter">The parameter the parameter policy is being created for.</param>
    /// <param name="reference">The reference to resolve.</param>
    /// <returns>The <see cref="IParameterPolicy"/> for the parameter.</returns>
    public IParameterPolicy Create(RoutePatternParameterPart? parameter, RoutePatternParameterPolicyReference reference)
    {
        ArgumentNullException.ThrowIfNull(reference);
 
        Debug.Assert(reference.ParameterPolicy != null || reference.Content != null);
 
        if (reference.ParameterPolicy != null)
        {
            return Create(parameter, reference.ParameterPolicy);
        }
 
        if (reference.Content != null)
        {
            return Create(parameter, reference.Content);
        }
 
        // Unreachable
        throw new NotSupportedException();
    }
}