using Microsoft.AspNetCore.Authorization;
using Microsoft.Extensions.Options;

namespace LCU.API.Internal.Operations.IncentiveApi.Authorization;

public class PermissionPolicyProvider : IAuthorizationPolicyProvider
{
    const string POLICY_PREFIX = "Permission";
    public DefaultAuthorizationPolicyProvider FallbackPolicyProvider { get; }

    public PermissionPolicyProvider(IOptions<AuthorizationOptions> options)
    {
        FallbackPolicyProvider = new DefaultAuthorizationPolicyProvider(options);
    }

    public Task<AuthorizationPolicy> GetDefaultPolicyAsync() => FallbackPolicyProvider.GetDefaultPolicyAsync();

    public Task<AuthorizationPolicy> GetFallbackPolicyAsync() => FallbackPolicyProvider.GetFallbackPolicyAsync();

    public Task<AuthorizationPolicy> GetPolicyAsync(string policyName)
    {
        if (policyName.StartsWith(POLICY_PREFIX, StringComparison.OrdinalIgnoreCase))
        {
            var allowedPermissions = policyName.Substring(POLICY_PREFIX.Length);
            var policy = new AuthorizationPolicyBuilder();
            policy.AddRequirements(new PermissionRequirement(allowedPermissions));
            return Task.FromResult(policy.Build());
        }

        return FallbackPolicyProvider.GetPolicyAsync(policyName);
    }
}