// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using Microsoft.AspNetCore.Routing.Constraints;
using Microsoft.AspNetCore.Routing.Patterns;
using Microsoft.Extensions.Options;
 
namespace Microsoft.AspNetCore.Routing;
 
internal sealed class DefaultParameterPolicyFactory : ParameterPolicyFactory
{
    private readonly RouteOptions _options;
    private readonly IServiceProvider _serviceProvider;
 
    public DefaultParameterPolicyFactory(
        IOptions<RouteOptions> options,
        IServiceProvider serviceProvider)
    {
        _options = options.Value;
        _serviceProvider = serviceProvider;
    }
 
    public override IParameterPolicy Create(RoutePatternParameterPart? parameter, IParameterPolicy parameterPolicy)
    {
        ArgumentNullException.ThrowIfNull(parameterPolicy);
 
        if (parameterPolicy is IRouteConstraint routeConstraint)
        {
            return InitializeRouteConstraint(parameter?.IsOptional ?? false, routeConstraint);
        }
 
        return parameterPolicy;
    }
 
    public override IParameterPolicy Create(RoutePatternParameterPart? parameter, string inlineText)
    {
        ArgumentNullException.ThrowIfNull(inlineText);
 
        var parameterPolicy = ParameterPolicyActivator.ResolveParameterPolicy<IParameterPolicy>(
            _options.TrimmerSafeConstraintMap,
            _serviceProvider,
            inlineText,
            out var parameterPolicyKey);
 
        if (parameterPolicy == null)
        {
            throw new InvalidOperationException(Resources.FormatRoutePattern_ConstraintReferenceNotFound(
                parameterPolicyKey,
                typeof(RouteOptions),
                nameof(RouteOptions.ConstraintMap)));
        }
 
        if (parameterPolicy is IRouteConstraint constraint)
        {
            return InitializeRouteConstraint(parameter?.IsOptional ?? false, constraint);
        }
 
        return parameterPolicy;
    }
 
    private static IParameterPolicy InitializeRouteConstraint(
        bool optional,
        IRouteConstraint routeConstraint)
    {
        if (optional)
        {
            routeConstraint = new OptionalRouteConstraint(routeConstraint);
        }
 
        return routeConstraint;
    }
}