using System;

using System.Collections.Generic;

using System.Reflection;

namespace Python.Runtime

{

/// <summary>

/// Implements a Python binding type for CLR methods. These work much like

/// standard Python method bindings, but the same type is used to bind

/// both static and instance methods.

/// </summary>

internal class MethodBinding : ExtensionType

{

internal MethodInfo info;

internal MethodObject m;

internal IntPtr target;

internal IntPtr targetType;

public MethodBinding(MethodObject m, IntPtr target, IntPtr targetType)

{

Runtime.XIncref(target);

this.target = target;

Runtime.XIncref(targetType);

if (targetType == IntPtr.Zero)

{

targetType = Runtime.PyObject_Type(target);

}

this.targetType = targetType;

this.info = null;

this.m = m;

}

public MethodBinding(MethodObject m, IntPtr target) : this(m, target, IntPtr.Zero)

{

}

/// <summary>

/// Implement binding of generic methods using the subscript syntax [].

/// </summary>

public static IntPtr mp_subscript(IntPtr tp, IntPtr idx)

{

var self = (MethodBinding)GetManagedObject(tp);

Type[] types = Runtime.PythonArgsToTypeArray(idx);

if (types == null)

{

return Exceptions.RaiseTypeError("type(s) expected");

}

MethodInfo mi = MethodBinder.MatchParameters(self.m.info, types);

if (mi == null)

{

return Exceptions.RaiseTypeError("No match found for given type params");

}

var mb = new MethodBinding(self.m, self.target) { info = mi };

return mb.pyHandle;

}

/// <summary>

/// MethodBinding __getattribute__ implementation.

/// </summary>

public static IntPtr tp_getattro(IntPtr ob, IntPtr key)

{

var self = (MethodBinding)GetManagedObject(ob);

if (!Runtime.PyString_Check(key))

{

Exceptions.SetError(Exceptions.TypeError, "string expected");

return IntPtr.Zero;

}

string name = Runtime.GetManagedString(key);

switch (name)

{

case "__doc__":

IntPtr doc = self.m.GetDocString();

Runtime.XIncref(doc);

return doc;

// FIXME: deprecate __overloads__ soon...

case "__overloads__":

case "Overloads":

var om = new OverloadMapper(self.m, self.target);

return om.pyHandle;

default:

return Runtime.PyObject_GenericGetAttr(ob, key);

}

}

/// <summary>

/// MethodBinding __call__ implementation.

/// </summary>

public static IntPtr tp_call(IntPtr ob, IntPtr args, IntPtr kw)

{

var self = (MethodBinding)GetManagedObject(ob);

// This works around a situation where the wrong generic method is picked,

// for example this method in the tests: string Overloaded<T>(int arg1, int arg2, string arg3)

if (self.info != null)

{

if (self.info.IsGenericMethod)

{

var len = Runtime.PyTuple_Size(args); //FIXME: Never used

Type[] sigTp = Runtime.PythonArgsToTypeArray(args, true);

if (sigTp != null)

{

Type[] genericTp = self.info.GetGenericArguments();

MethodInfo betterMatch = MethodBinder.MatchSignatureAndParameters(self.m.info, genericTp, sigTp);

if (betterMatch != null)

{

self.info = betterMatch;

}

}

}

}

// This supports calling a method 'unbound', passing the instance

// as the first argument. Note that this is not supported if any

// of the overloads are static since we can't know if the intent

// was to call the static method or the unbound instance method.

var disposeList = new List<IntPtr>();

try

{

IntPtr target = self.target;

if (target == IntPtr.Zero && !self.m.IsStatic())

{

var len = Runtime.PyTuple_Size(args);

if (len < 1)

{

Exceptions.SetError(Exceptions.TypeError, "not enough arguments");

return IntPtr.Zero;

}

target = Runtime.PyTuple_GetItem(args, 0);

Runtime.XIncref(target);

disposeList.Add(target);

args = Runtime.PyTuple_GetSlice(args, 1, len);

disposeList.Add(args);

}

// if the class is a IPythonDerivedClass and target is not the same as self.targetType

// (eg if calling the base class method) then call the original base class method instead

// of the target method.

IntPtr superType = IntPtr.Zero;

if (Runtime.PyObject_TYPE(target) != self.targetType)

{

var inst = GetManagedObject(target) as CLRObject;

if (inst?.inst is IPythonDerivedType)

{

var baseType = GetManagedObject(self.targetType) as ClassBase;

if (baseType != null)

{

string baseMethodName = "_" + baseType.type.Name + "__" + self.m.name;

IntPtr baseMethod = Runtime.PyObject_GetAttrString(target, baseMethodName);

if (baseMethod != IntPtr.Zero)

{

var baseSelf = GetManagedObject(baseMethod) as MethodBinding;

if (baseSelf != null)

{

self = baseSelf;

}

Runtime.XDecref(baseMethod);

}

else

{

Runtime.PyErr_Clear();

}

}

}

}

return self.m.Invoke(target, args, kw, self.info);

}

finally

{

foreach (IntPtr ptr in disposeList)

{

Runtime.XDecref(ptr);

}

}

}

/// <summary>

/// MethodBinding __hash__ implementation.

/// </summary>

public static IntPtr tp_hash(IntPtr ob)

{

var self = (MethodBinding)GetManagedObject(ob);

long x = 0;

long y = 0;

if (self.target != IntPtr.Zero)

{

x = Runtime.PyObject_Hash(self.target).ToInt64();

if (x == -1)

{

return new IntPtr(-1);

}

}

y = Runtime.PyObject_Hash(self.m.pyHandle).ToInt64();

if (y == -1)

{

return new IntPtr(-1);

}

x ^= y;

if (x == -1)

{

x = -1;

}

return new IntPtr(x);

}

/// <summary>

/// MethodBinding __repr__ implementation.

/// </summary>

public static IntPtr tp_repr(IntPtr ob)

{

var self = (MethodBinding)GetManagedObject(ob);

string type = self.target == IntPtr.Zero ? "unbound" : "bound";

string name = self.m.name;

return Runtime.PyString_FromString($"<{type} method '{name}'>");

}

/// <summary>

/// MethodBinding dealloc implementation.

/// </summary>

public new static void tp_dealloc(IntPtr ob)

{

var self = (MethodBinding)GetManagedObject(ob);

Runtime.XDecref(self.target);

Runtime.XDecref(self.targetType);

FinalizeObject(self);

}

}

}