#if UNITY_IOS || UNITY_TVOS

using System;
using System.Reflection;
using UnityEditor.iOS.Xcode;

namespace AppleAuth.Editor
{
    public static class ProjectCapabilityManagerExtension
    {
        private const string EntitlementsArrayKey = "com.apple.developer.applesignin";
        private const string DefaultAccessLevel = "Default";
        private const string AuthenticationServicesFramework = "AuthenticationServices.framework";
        private const BindingFlags NonPublicInstanceBinding = BindingFlags.NonPublic | BindingFlags.Instance;
        private const BindingFlags PublicInstanceBinding = BindingFlags.Public | BindingFlags.Instance;

        /// <summary>
        /// Extension method for ProjectCapabilityManager to add the Sign In With Apple capability in compatibility mode.
        /// In particular, adds the AuthenticationServices.framework as an Optional framework, preventing crashes in
        /// iOS versions previous to 13.0
        /// </summary>
        /// <param name="manager">The manager for the main target to use when adding the Sign In With Apple capability.</param>
        /// <param name="unityFrameworkTargetGuid">The GUID for the UnityFramework target. If null, it will use the main target GUID.</param>
        public static void AddSignInWithAppleWithCompatibility(this ProjectCapabilityManager manager, string unityFrameworkTargetGuid = null)
        {
            var managerType = typeof(ProjectCapabilityManager);
            
            var projectField = managerType.GetField("project", NonPublicInstanceBinding);
            var targetGuidField = managerType.GetField("m_TargetGuid", NonPublicInstanceBinding);
            var entitlementFilePathField = managerType.GetField("m_EntitlementFilePath", NonPublicInstanceBinding);
            var getOrCreateEntitlementDocMethod = managerType.GetMethod("GetOrCreateEntitlementDoc", NonPublicInstanceBinding);

            // in old unity versions PBXCapabilityType had internal ctor; that was changed to public afterwards - try both
            var constructorInfo = GetPBXCapabilityTypeConstructor(PublicInstanceBinding) ??
                                  GetPBXCapabilityTypeConstructor(NonPublicInstanceBinding);
            
            if (projectField == null || targetGuidField == null  || entitlementFilePathField == null ||
                getOrCreateEntitlementDocMethod == null || constructorInfo == null)
                throw new Exception("Can't Add Sign In With Apple programatically in this Unity version");
            
            var entitlementFilePath = entitlementFilePathField.GetValue(manager) as string;
            var entitlementDoc = getOrCreateEntitlementDocMethod.Invoke(manager, new object[] { }) as PlistDocument;
            if (entitlementDoc != null)
            {
                var plistArray = new PlistElementArray();
                plistArray.AddString(DefaultAccessLevel);
                entitlementDoc.root[EntitlementsArrayKey] = plistArray;
            }

            var project = projectField.GetValue(manager) as PBXProject;
            if (project != null)
            {
                var mainTargetGuid = targetGuidField.GetValue(manager) as string;
                var capabilityType = constructorInfo.Invoke(new object[] { "com.apple.developer.applesignin.custom", true, string.Empty, true }) as PBXCapabilityType;

                var targetGuidToAddFramework = unityFrameworkTargetGuid;
                if (targetGuidToAddFramework == null)
                {
                    targetGuidToAddFramework = mainTargetGuid;
                }

                project.AddFrameworkToProject(targetGuidToAddFramework, AuthenticationServicesFramework, true);
                project.AddCapability(mainTargetGuid, capabilityType, entitlementFilePath, false);
            }
        }
        
        private static ConstructorInfo GetPBXCapabilityTypeConstructor(BindingFlags flags)
        {
            return typeof(PBXCapabilityType).GetConstructor(
                flags,
                null,
                new[] {typeof(string), typeof(bool), typeof(string), typeof(bool)},
                null);
        }
    }
}

#endif