/* ****************************************************************************

 *

 * Copyright (c) Microsoft Corporation. 

 *

 * This source code is subject to terms and conditions of the Microsoft Public License. A 

 * copy of the license can be found in the License.html file at the root of this distribution. If 

 * you cannot locate the  Microsoft Public License, please send an email to 

 * dlr@microsoft.com. By using this source code in any fashion, you are agreeing to be bound 

 * by the terms of the Microsoft Public License.

 *

 * You must not remove this notice, or any other, from this software.

 *

 *

 * ***************************************************************************/



using System;

using System.Collections.Generic;

using System.Reflection;

using System.Threading;



using Microsoft.Scripting;

using Microsoft.Scripting.Math;

using Microsoft.Scripting.Runtime;

using Microsoft.Scripting.Utils;



using IronPython.Runtime.Types;



#if CLR2

using Complex = Microsoft.Scripting.Math.Complex64;

#else

using System.Numerics;

#endif



namespace IronPython.Runtime.Operations {



    /// <summary>

    /// Contains Python extension methods that are added to object

    /// </summary>

    public static class ObjectOps {

        /// <summary> Types for which the pickle module has built-in support (from PEP 307 case 2)  </summary>

        [MultiRuntimeAware]

        private static Dictionary<PythonType, object> _nativelyPickleableTypes;



        /// <summary>

        /// __class__, a custom slot so that it works for both objects and types.

        /// </summary>

        [SlotField]

        public static PythonTypeSlot __class__ = new PythonTypeTypeSlot();



        /// <summary>

        /// Removes an attribute from the provided member

        /// </summary>

        public static void __delattr__(CodeContext/*!*/ context, object self, string name) {

            if (self is PythonType) {

                throw PythonOps.TypeError("can't apply this __delattr__ to type object");

            }



            PythonOps.ObjectDeleteAttribute(context, self, name);

        }



        /// <summary>

        /// Returns the hash code of the given object

        /// </summary>

        public static int __hash__(object self) {

            if (self == null) return NoneTypeOps.NoneHashCode;

            return self.GetHashCode();

        }



        /// <summary>

        /// Gets the specified attribute from the object without running any custom lookup behavior

        /// (__getattr__ and __getattribute__)

        /// </summary>

        public static object __getattribute__(CodeContext/*!*/ context, object self, string name) {

            return PythonOps.ObjectGetAttribute(context, self, name);

        }



        /// <summary>

        /// Initializes the object.  The base class does nothing.

        /// </summary>

        public static void __init__(CodeContext/*!*/ context, object self) {

        }



        /// <summary>

        /// Initializes the object.  The base class does nothing.

        /// </summary>

        public static void __init__(CodeContext/*!*/ context, object self, [NotNull]params object[] args\u00F8) {

            InstanceOps.CheckInitArgs(context, null, args\u00F8, self);

        }



        /// <summary>

        /// Initializes the object.  The base class does nothing.

        /// </summary>

        public static void __init__(CodeContext/*!*/ context, object self, [ParamDictionary]IDictionary<object, object> kwargs, params object[] args\u00F8) {

            InstanceOps.CheckInitArgs(context, kwargs, args\u00F8, self);

        }



        /// <summary>

        /// Creates a new instance of the type

        /// </summary>

        [StaticExtensionMethod]

        public static object __new__(CodeContext/*!*/ context, PythonType cls) {

            if (cls == null) {

                throw PythonOps.TypeError("__new__ expected type object, got {0}", PythonOps.Repr(context, DynamicHelpers.GetPythonType(cls)));

            }



            return cls.CreateInstance(context);

        }



        /// <summary>

        /// Creates a new instance of the type

        /// </summary>

        [StaticExtensionMethod]

        public static object __new__(CodeContext/*!*/ context, PythonType cls, [NotNull]params object[] args\u00F8) {

            if (cls == null) {

                throw PythonOps.TypeError("__new__ expected type object, got {0}", PythonOps.Repr(context, DynamicHelpers.GetPythonType(cls)));

            }



            InstanceOps.CheckNewArgs(context, null, args\u00F8, cls);



            return cls.CreateInstance(context);

        }



        /// <summary>

        /// Creates a new instance of the type

        /// </summary>

        [StaticExtensionMethod]

        public static object __new__(CodeContext/*!*/ context, PythonType cls, [ParamDictionary]IDictionary<object, object> kwargs\u00F8, [NotNull]params object[] args\u00F8) {

            if (cls == null) {

                throw PythonOps.TypeError("__new__ expected type object, got {0}", PythonOps.Repr(context, DynamicHelpers.GetPythonType(cls)));

            }



            InstanceOps.CheckNewArgs(context, kwargs\u00F8, args\u00F8, cls);



            return cls.CreateInstance(context);

        }



        /// <summary>

        /// Runs the pickle protocol

        /// </summary>

        public static object __reduce__(CodeContext/*!*/ context, object self) {

            return __reduce_ex__(context, self, 0);

        }



        /// <summary>

        /// Runs the pickle protocol

        /// </summary>

        public static object __reduce_ex__(CodeContext/*!*/ context, object self) {

            return __reduce_ex__(context, self, 0);

        }



        /// <summary>

        /// Runs the pickle protocol

        /// </summary>

        public static object __reduce_ex__(CodeContext/*!*/ context, object self, object protocol) {

            object objectReduce = PythonOps.GetBoundAttr(context, DynamicHelpers.GetPythonTypeFromType(typeof(object)), "__reduce__");

            object myReduce;

            if (PythonOps.TryGetBoundAttr(context, DynamicHelpers.GetPythonType(self), "__reduce__", out myReduce)) {

                if (!PythonOps.IsRetBool(myReduce, objectReduce)) {

                    // A derived class overrode __reduce__ but not __reduce_ex__, so call

                    // specialized __reduce__ instead of generic __reduce_ex__.

                    // (see the "The __reduce_ex__ API" section of PEP 307)

                    return PythonOps.CallWithContext(context, myReduce, self);

                }

            }



            if (PythonContext.GetContext(context).ConvertToInt32(protocol) < 2) {

                return ReduceProtocol0(context, self);

            } else {

                return ReduceProtocol2(context, self);

            }

        }



        /// <summary>

        /// Returns the code representation of the object.  The default implementation returns

        /// a string which consists of the type and a unique numerical identifier.

        /// </summary>

        public static string __repr__(object self) {

            return String.Format("<{0} object at {1}>",

                DynamicHelpers.GetPythonType(self).Name,

                PythonOps.HexId(self));

        }



        /// <summary>

        /// Sets an attribute on the object without running any custom object defined behavior.

        /// </summary>

        public static void __setattr__(CodeContext/*!*/ context, object self, string name, object value) {

            if (self is PythonType) {

                throw PythonOps.TypeError("can't apply this __setattr__ to type object");

            }



            PythonOps.ObjectSetAttribute(context, self, name, value);

        }



        private static int AdjustPointerSize(int size) {

            if (IntPtr.Size == 4) {

                return size;

            }



            return size * 2;

        }



        /// <summary>

        /// Returns the number of bytes of memory required to allocate the object.

        /// </summary>

        public static int __sizeof__(object self) {

            IPythonObject ipo = self as IPythonObject;

            int res = AdjustPointerSize(8); // vtable, sync blk

            if (ipo != null) {

                res += AdjustPointerSize(12); // class, dict, slots 

            }



            Type t = PythonTypeOps.GetFinalSystemType(DynamicHelpers.GetPythonType(self));

            res += GetTypeSize(t);



            return res;

        }



        private static int GetTypeSize(Type t) {

            FieldInfo[] fields = t.GetFields(System.Reflection.BindingFlags.FlattenHierarchy | System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Public);

            int res = 0;

            foreach (FieldInfo fi in fields) {

                if (fi.FieldType.IsClass || fi.FieldType.IsInterface) {

                    res += AdjustPointerSize(4);

                } else if (fi.FieldType.IsPrimitive) {

                    return System.Runtime.InteropServices.Marshal.SizeOf(fi.FieldType);

                } else {

                    res += GetTypeSize(fi.FieldType);

                }

            }



            return res;

        }



        /// <summary>

        /// Returns a friendly string representation of the object. 

        /// </summary>

        public static string __str__(CodeContext/*!*/ context, object o) {

            return PythonOps.Repr(context, o);

        }



        public static NotImplementedType __subclasshook__(params object[] args) {

            return NotImplementedType.Value;

        }



        public static string __format__(CodeContext/*!*/ context, object self, [NotNull]string/*!*/ formatSpec) {

            string text = PythonOps.ToString(context, self);



            StringFormatSpec spec = StringFormatSpec.FromString(formatSpec);



            if (spec.Type != null && spec.Type != 's') {

                throw PythonOps.ValueError("Unknown format code '{0}' for object of type 'str'", spec.Type.Value.ToString());

            } else if (spec.Sign != null) {

                throw PythonOps.ValueError("Sign not allowed in string format specifier");

            } else if (spec.Alignment == '=') {

                throw PythonOps.ValueError("'=' alignment not allowed in string format specifier");

            }



            // apply precision to shorten the string first

            if (spec.Precision != null) {

                int precision = spec.Precision.Value;

                if (text.Length > precision) {

                    text = text.Substring(0, precision);

                }

            }



            // then apply the minimum width & padding

            text = spec.AlignText(text);



            // finally return the text

            return text;

        }



        #region Pickle helpers



        // This is a dynamically-initialized property rather than a statically-initialized field

        // to avoid a bootstrapping dependency loop

        private static Dictionary<PythonType, object> NativelyPickleableTypes {

            get {

                if (_nativelyPickleableTypes == null) {

                    Dictionary<PythonType, object> typeDict = new Dictionary<PythonType, object>();

                    typeDict.Add(TypeCache.Null, null);

                    typeDict.Add(DynamicHelpers.GetPythonTypeFromType(typeof(bool)), null);

                    typeDict.Add(DynamicHelpers.GetPythonTypeFromType(typeof(int)), null);

                    typeDict.Add(DynamicHelpers.GetPythonTypeFromType(typeof(double)), null);

                    typeDict.Add(DynamicHelpers.GetPythonTypeFromType(typeof(Complex)), null);

                    typeDict.Add(DynamicHelpers.GetPythonTypeFromType(typeof(string)), null);

                    typeDict.Add(DynamicHelpers.GetPythonTypeFromType(typeof(PythonTuple)), null);

                    typeDict.Add(DynamicHelpers.GetPythonTypeFromType(typeof(List)), null);

                    typeDict.Add(DynamicHelpers.GetPythonTypeFromType(typeof(PythonDictionary)), null);

                    typeDict.Add(DynamicHelpers.GetPythonTypeFromType(typeof(OldInstance)), null);

                    typeDict.Add(DynamicHelpers.GetPythonTypeFromType(typeof(OldClass)), null);

                    typeDict.Add(DynamicHelpers.GetPythonTypeFromType(typeof(PythonFunction)), null);

                    typeDict.Add(DynamicHelpers.GetPythonTypeFromType(typeof(BuiltinFunction)), null);



                    // type dict needs to be ensured to be fully initialized before assigning back

                    Thread.MemoryBarrier();

                    _nativelyPickleableTypes = typeDict;

                }

                return _nativelyPickleableTypes;

            }

        }



        /// <summary>

        /// Return a dict that maps slot names to slot values, but only include slots that have been assigned to.

        /// Looks up slots in base types as well as the current type.

        /// 

        /// Sort-of Python equivalent (doesn't look up base slots, while the real code does):

        ///   return dict([(slot, getattr(self, slot)) for slot in type(self).__slots__ if hasattr(self, slot)])

        /// 

        /// Return null if the object has no __slots__, or empty dict if it has __slots__ but none are initialized.

        /// </summary>

        private static PythonDictionary GetInitializedSlotValues(object obj) {

            PythonDictionary initializedSlotValues = new PythonDictionary();

            IList<PythonType> mro = DynamicHelpers.GetPythonType(obj).ResolutionOrder;

            object slots;

            object slotValue;

            foreach (object type in mro) {

                if (PythonOps.TryGetBoundAttr(type, "__slots__", out slots)) {

                    List<string> slotNames = PythonType.SlotsToList(slots);

                    foreach (string slotName in slotNames) {

                        if (slotName == "__dict__") continue;

                        // don't reassign same-named slots from types earlier in the MRO

                        if (initializedSlotValues.__contains__(slotName)) continue;

                        if (PythonOps.TryGetBoundAttr(obj, slotName, out slotValue)) {

                            initializedSlotValues[slotName] = slotValue;

                        }

                    }

                }

            }

            if (initializedSlotValues.Count == 0) return null;

            return initializedSlotValues;

        }



        /// <summary>

        /// Implements the default __reduce_ex__ method as specified by PEP 307 case 2 (new-style instance, protocol 0 or 1)

        /// </summary>

        internal static PythonTuple ReduceProtocol0(CodeContext/*!*/ context, object self) {

            // CPython implements this in copy_reg._reduce_ex



            PythonType myType = DynamicHelpers.GetPythonType(self); // PEP 307 calls this "D"

            ThrowIfNativelyPickable(myType);



            object getState;

            bool hasGetState = PythonOps.TryGetBoundAttr(context, self, "__getstate__", out getState);



            object slots;

            if (PythonOps.TryGetBoundAttr(context, myType, "__slots__", out slots) && PythonOps.Length(slots) > 0 && !hasGetState) {

                // ??? does this work with superclass slots?

                throw PythonOps.TypeError("a class that defines __slots__ without defining __getstate__ cannot be pickled with protocols 0 or 1");

            }



            PythonType closestNonPythonBase = FindClosestNonPythonBase(myType); // PEP 307 calls this "B"



            object func = PythonContext.GetContext(context).PythonReconstructor;



            object funcArgs = PythonTuple.MakeTuple(

                myType,

                closestNonPythonBase,

                TypeCache.Object == closestNonPythonBase ? null : PythonCalls.Call(context, closestNonPythonBase, self)

            );



            object state;

            if (hasGetState) {

                state = PythonOps.CallWithContext(context, getState);

            } else {

                IPythonObject ipo = self as IPythonObject;

                if (ipo != null) {

                    state = ipo.Dict;

                } else if (!PythonOps.TryGetBoundAttr(context, self, "__dict__", out state)) {

                    state = null;

                }

            }

            if (!PythonOps.IsTrue(state)) state = null;



            return PythonTuple.MakeTuple(func, funcArgs, state);

        }



        private static void ThrowIfNativelyPickable(PythonType type) {

            if (NativelyPickleableTypes.ContainsKey(type)) {

                throw PythonOps.TypeError("can't pickle {0} objects", type.Name);

            }

        }



        /// <summary>

        /// Returns the closest base class (in terms of MRO) that isn't defined in Python code

        /// </summary>

        private static PythonType FindClosestNonPythonBase(PythonType type) {

            foreach (PythonType pythonBase in type.ResolutionOrder) {

                if (pythonBase.IsSystemType) {

                    return pythonBase;

                }

            }

            throw PythonOps.TypeError("can't pickle {0} instance: no non-Python bases found", type.Name);

        }



        /// <summary>

        /// Implements the default __reduce_ex__ method as specified by PEP 307 case 3 (new-style instance, protocol 2)

        /// </summary>

        private static PythonTuple ReduceProtocol2(CodeContext/*!*/ context, object self) {

            PythonType myType = DynamicHelpers.GetPythonType(self);



            object func, state, listIterator, dictIterator;

            object[] funcArgs;



            func = PythonContext.GetContext(context).NewObject;



            object getNewArgsCallable;

            if (PythonOps.TryGetBoundAttr(context, myType, "__getnewargs__", out getNewArgsCallable)) {

                // TypeError will bubble up if __getnewargs__ isn't callable

                PythonTuple newArgs = PythonOps.CallWithContext(context, getNewArgsCallable, self) as PythonTuple;

                if (newArgs == null) {

                    throw PythonOps.TypeError("__getnewargs__ should return a tuple");

                }

                funcArgs = new object[1 + newArgs.Count];

                funcArgs[0] = myType;

                for (int i = 0; i < newArgs.Count; i++) funcArgs[i + 1] = newArgs[i];

            } else {

                funcArgs = new object[] { myType };

            }



            if (!PythonTypeOps.TryInvokeUnaryOperator(context,

                    self,

                    "__getstate__",

                    out state)) {

                object dict;

                IPythonObject ipo = self as IPythonObject;

                if (ipo != null) {

                    dict = ipo.Dict;

                } else if (!PythonOps.TryGetBoundAttr(context, self, "__dict__", out dict)) {

                    dict = null;

                }



                PythonDictionary initializedSlotValues = GetInitializedSlotValues(self);

                if (initializedSlotValues != null && initializedSlotValues.Count == 0) {

                    initializedSlotValues = null;

                }



                if (dict == null && initializedSlotValues == null) state = null;

                else if (dict != null && initializedSlotValues == null) state = dict;

                else if (dict != null && initializedSlotValues != null) state = PythonTuple.MakeTuple(dict, initializedSlotValues);

                else   /*dict == null && initializedSlotValues != null*/ state = PythonTuple.MakeTuple(null, initializedSlotValues);

            }



            listIterator = null;

            if (self is List) {

                listIterator = PythonOps.GetEnumerator(self);

            }



            dictIterator = null;

            if (self is PythonDictionary || self is PythonDictionary) {

                dictIterator = PythonOps.Invoke(context, self, "iteritems", ArrayUtils.EmptyObjects);

            }



            return PythonTuple.MakeTuple(func, PythonTuple.MakeTuple(funcArgs), state, listIterator, dictIterator);

        }



        #endregion        

    }

}