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using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Reflection;
using XenAdmin.ServerDBs;

namespace XenAdmin.Core
{
    public static class SimpleProxyMethodParser
    {
        public static ProxyMethodInfo ParseTypeAndNameOnly(string proxyMethodName)
        {
            string typeName = GetTypeName(proxyMethodName);
            MethodType fakeMethodType = proxyMethodName.StartsWith(String.Format("{0}_", typeName)) ? MethodType.Sync : MethodType.Async;
            string methodName = fakeMethodType == MethodType.Sync ? proxyMethodName.Substring(typeName.Length + 1) : proxyMethodName.Substring(7 + typeName.Length);
            return new ProxyMethodInfo(methodName, typeName);
        }

        private static string GetTypeName(string proxyMethodName)
        {
            // This only works because DbProxy.AllTypes has longest names first,
            // so we never accidentally match a substring.
            foreach (string type in AllTypes)
            {
                if (proxyMethodName.StartsWith(string.Format("{0}_", type)) || proxyMethodName.StartsWith(string.Format("async_{0}_", type)))
                {
                    return type;
                }
            }
            return null;
        }
        // Find all XenObject types. Actually the ones we want are those with
        // associated Proxy_ types (basically, the ones in the public API).
        private static readonly object XenApiTypesLock = new object();
        private static ReadOnlyCollection<string> _xenApiTypeNames;
        public static ReadOnlyCollection<string> AllTypes
        {
            get
            {
                lock (XenApiTypesLock)
                {
                    if (_xenApiTypeNames == null)
                    {
                        List<string> names = new List<string>();

                        foreach (Type type in Assembly.Load(new AssemblyName("XenModel")).GetTypes())
                        {
                            if (type.Namespace == "XenAPI" && type.Name.StartsWith("Proxy_"))
                                names.Add(type.Name.Substring(6).ToLower());
                        }

                        // We sort the names in reverse alphabetical order, so that later in
                        // ProxyMethodNameParser.GetTypeName(), we find the longest matching name.
                        names.Sort((x, y) => -x.CompareTo(y));
                        _xenApiTypeNames = new ReadOnlyCollection<string>(names);
                    }
                    return _xenApiTypeNames;
                }
            }
        }
    }
}