source: TFP-WebServer/WebServer/src/WebAPI/APIs/Permissions/WebModules.cs@ 487

using System;
using System.Collections.Generic;
using System.Net;
using JetBrains.Annotations;
using Utf8Json;
using Webserver.Permissions;

namespace Webserver.WebAPI.APIs.Permissions {
        [UsedImplicitly]
        public class WebModules : AbsRestApi {
                private const string propertyModule = "module";
                private const string propertyPermissionLevelGlobal = "permissionLevelGlobal";
                private const string propertyPermissionLevelPerMethod = "permissionLevelPerMethod";
                private const string propertyIsDefault = "isDefault";
                

                private static readonly byte[] jsonKeyModule = JsonWriter.GetEncodedPropertyNameWithBeginObject (propertyModule);
                private static readonly byte[] jsonKeyPermissionLevelGlobal = JsonWriter.GetEncodedPropertyNameWithPrefixValueSeparator (propertyPermissionLevelGlobal);
                private static readonly byte[] jsonKeyPermissionLevelPerMethod = JsonWriter.GetEncodedPropertyNameWithPrefixValueSeparator (propertyPermissionLevelPerMethod);
                private static readonly byte[] jsonKeyIsDefault = JsonWriter.GetEncodedPropertyNameWithPrefixValueSeparator (propertyIsDefault);

                private static readonly byte[][] jsonMethodNameKeys;

                static WebModules () {
                        jsonMethodNameKeys = new byte[(int)ERequestMethod.Count][];
                        for (int i = 0; i < jsonMethodNameKeys.Length; i++) {
                                ERequestMethod method = (ERequestMethod)i;
                                jsonMethodNameKeys [i] = JsonWriter.GetEncodedPropertyName (method.ToStringCached ());
                        }
                }

                private static AdminWebModules ModulesInstance => AdminWebModules.Instance;

                protected override void HandleRestGet (RequestContext _context) {
                        string id = _context.RequestPath;

                        PrepareEnvelopedResult (out JsonWriter writer);
                        
                        if (string.IsNullOrEmpty (id)) {
                                
                                writer.WriteBeginArray ();
                        
                                bool first = true;
                                foreach (AdminWebModules.WebModule module in ModulesInstance.GetModules ()) {
                                        if (!first) {
                                                writer.WriteValueSeparator ();
                                        }

                                        first = false;

                                        writeModuleJson (ref writer, module);
                                }

                                writer.WriteEndArray ();
                                
                                SendEnvelopedResult (_context, ref writer);
                                return;
                        }

                        writer.WriteRaw (WebUtils.JsonEmptyData);
                        SendEnvelopedResult (_context, ref writer, HttpStatusCode.BadRequest);
                }

                private void writeModuleJson (ref JsonWriter _writer, AdminWebModules.WebModule _module) {
                        _writer.WriteRaw (jsonKeyModule);
                        _writer.WriteString (_module.Name);
                        _writer.WriteRaw (jsonKeyPermissionLevelGlobal);
                        _writer.WriteInt32 (_module.LevelGlobal);
                        _writer.WriteRaw (jsonKeyPermissionLevelPerMethod);

                        _writer.WriteBeginObject ();

                        if (_module.LevelPerMethod != null) {
                                bool first = true;
                                for (int iMethod = 0; iMethod < _module.LevelPerMethod.Length; iMethod++) {
                                        int methodLevel = _module.LevelPerMethod [iMethod];

                                        if (methodLevel == AdminWebModules.MethodLevelNotSupported) {
                                                continue;
                                        }

                                        if (!first) {
                                                _writer.WriteValueSeparator ();
                                        }

                                        first = false;

                                        _writer.WriteRaw (jsonMethodNameKeys [iMethod]);
                                        if (methodLevel == AdminWebModules.MethodLevelInheritGlobal) {
                                                _writer.WriteString (AdminWebModules.MethodLevelInheritKeyword);
                                        } else {
                                                _writer.WriteInt32 (methodLevel);
                                        }
                                }
                        }

                        _writer.WriteEndObject ();

                        _writer.WriteRaw (jsonKeyIsDefault);
                        _writer.WriteBoolean (_module.IsDefault);

                        _writer.WriteEndObject ();
                }

                protected override void HandleRestPost (RequestContext _context, IDictionary<string, object> _jsonInput, byte[] _jsonInputData) {
                        string id = _context.RequestPath;

                        if (string.IsNullOrEmpty (id)) {
                                SendEmptyResponse (_context, HttpStatusCode.BadRequest, _jsonInputData, EApiErrorCode.NO_MODULE);
                                return;
                        }

                        if (!AdminWebModules.Instance.IsKnownModule (id)) {
                                SendEmptyResponse (_context, HttpStatusCode.BadRequest, _jsonInputData, EApiErrorCode.INVALID_MODULE);
                                return;
                        }

                        AdminWebModules.WebModule module = AdminWebModules.Instance.GetModule (id);

                        if (_jsonInput.ContainsKey (propertyPermissionLevelGlobal)) {
                                if (!JsonCommons.TryGetJsonField (_jsonInput, propertyPermissionLevelGlobal, out int permissionLevelGlobal)) {
                                        SendEmptyResponse (_context, HttpStatusCode.BadRequest, _jsonInputData, EApiErrorCode.INVALID_PERMISSION_LEVEL_GLOBAL);
                                        return;
                                }

                                module = module.SetLevelGlobal (permissionLevelGlobal);
                        }

                        if (_jsonInput.TryGetValue (propertyPermissionLevelPerMethod, out object perLevelField)) {
                                if (perLevelField is not IDictionary<string, object> perLevelObj) {
                                        SendEmptyResponse (_context, HttpStatusCode.BadRequest, _jsonInputData, EApiErrorCode.INVALID_PERMISSION_LEVEL_PER_METHOD_PROPERTY);
                                        return;
                                }

                                foreach ((string property, object valueObj) in perLevelObj) {
                                        if (!EnumUtils.TryParse (property, out ERequestMethod method, true)) {
                                                SendEmptyResponse (_context, HttpStatusCode.BadRequest, _jsonInputData, EApiErrorCode.INVALID_METHOD_NAME);
                                                return;
                                        }

                                        if (module.LevelPerMethod == null || module.LevelPerMethod [(int)method] == AdminWebModules.MethodLevelNotSupported) {
                                                SendEmptyResponse (_context, HttpStatusCode.BadRequest, _jsonInputData, EApiErrorCode.UNSUPPORTED_METHOD);
                                                return;
                                        }

                                        int permissionLevel;

                                        if (valueObj is string valueString) {
                                                if (!valueString.EqualsCaseInsensitive (AdminWebModules.MethodLevelInheritKeyword)) {
                                                        SendEmptyResponse (_context, HttpStatusCode.BadRequest, _jsonInputData, EApiErrorCode.INVALID_PERMISSION_STRING);
                                                        return;
                                                }                                               

                                                permissionLevel = AdminWebModules.MethodLevelInheritGlobal;
                                        } else if (valueObj is double valueDbl) {
                                                try {
                                                        permissionLevel = (int)valueDbl;
                                                } catch (Exception) {
                                                        SendEmptyResponse (_context, HttpStatusCode.BadRequest, _jsonInputData, EApiErrorCode.INVALID_PERMISSION_VALUE);
                                                        return;
                                                }
                                        } else {
                                                SendEmptyResponse (_context, HttpStatusCode.BadRequest, _jsonInputData, EApiErrorCode.INVALID_PERMISSION_VALUE_TYPE);
                                                return;
                                        }

                                        module = module.SetLevelForMethod (method, permissionLevel);
                                }
                        }

                        ModulesInstance.AddModule (module);

                        SendEmptyResponse (_context, HttpStatusCode.Created);
                }

                protected override void HandleRestDelete (RequestContext _context) {
                        string id = _context.RequestPath;

                        bool removed = ModulesInstance.RemoveModule (id);

                        SendEmptyResponse (_context, removed ? HttpStatusCode.NoContent : HttpStatusCode.NotFound);
                }

                protected override bool AllowPostWithId => true;

                public override int[] DefaultMethodPermissionLevels () => new[] {
                        AdminWebModules.MethodLevelNotSupported,
                        AdminWebModules.MethodLevelInheritGlobal,
                        AdminWebModules.MethodLevelInheritGlobal,
                        AdminWebModules.MethodLevelNotSupported,
                        AdminWebModules.MethodLevelInheritGlobal
                };
        }
}