import types
import time
import numpy as np
from functools import wraps


class SimPEGMetaClass(type):
    def __new__(cls, name, bases, attrs):
        return super(SimPEGMetaClass, cls).__new__(cls, name, bases, attrs)


def hook(obj, method, name=None, overwrite=False, silent=False):
    """
        This dynamically binds a method to the instance of the class.

        If name is None, the name of the method is used.
    """
    if name is None:
        name = method.__name__
        if name == '<lambda>':
            raise Exception('Must provide name to hook lambda functions.')
    if not hasattr(obj,name) or overwrite:
        setattr(obj, name, types.MethodType( method, obj ))
        if getattr(obj,'debug',False):
            print 'Method '+name+' was added to class.'
    elif not silent or getattr(obj,'debug',False):
        print 'Method '+name+' was not overwritten.'


def setKwargs(obj, **kwargs):
    """Sets key word arguments (kwargs) that are present in the object, throw an error if they don't exist."""
    for attr in kwargs:
        if hasattr(obj, attr):
            setattr(obj, attr, kwargs[attr])
        else:
            raise Exception('%s attr is not recognized' % attr)

    hook(obj,hook, silent=True)
    hook(obj,setKwargs, silent=True)

def printTitles(obj, printers, name='Print Titles', pad=''):
    titles = ''
    widths = 0
    for printer in printers:
        titles += ('{:^%i}'%printer['width']).format(printer['title']) + ''
        widths += printer['width']
    print pad + "{0} {1} {0}".format('='*((widths-1-len(name))/2), name)
    print pad + titles
    print pad + "%s" % '-'*widths

def printLine(obj, printers, pad=''):
    values = ''
    for printer in printers:
        values += ('{:^%i}'%printer['width']).format(printer['format'] % printer['value'](obj))
    print pad + values

def checkStoppers(obj, stoppers):
    # check stopping rules
    optimal = []
    critical = []
    for stopper in stoppers:
        l = stopper['left'](obj)
        r = stopper['right'](obj)
        if stopper['stopType'] == 'optimal':
            optimal.append(l <= r)
        if stopper['stopType'] == 'critical':
            critical.append(l <= r)

    if obj.debug: print 'checkStoppers.optimal: ', optimal
    if obj.debug: print 'checkStoppers.critical: ', critical

    return (len(optimal)>0 and all(optimal)) | (len(critical)>0 and any(critical))

def printStoppers(obj, stoppers, pad='', stop='STOP!', done='DONE!'):
    print pad + "%s%s%s" % ('-'*25,stop,'-'*25)
    for stopper in stoppers:
        l = stopper['left'](obj)
        r = stopper['right'](obj)
        print pad + stopper['str'] % (l<=r,l,r)
    print pad + "%s%s%s" % ('-'*25,done,'-'*25)

def callHooks(match, mainFirst=False):
    """
    Use this to wrap a funciton::

        @callHooks('doEndIteration')
        def doEndIteration(self):
            pass

    This will call everything named _doEndIteration* at the beginning of the function call.
    By default the master method (doEndIteration) is run after all of the sub methods (_doEndIteration*).
    This can be reversed by adding the mainFirst=True kwarg.
    """
    def callHooksWrap(f):
        @wraps(f)
        def wrapper(self,*args,**kwargs):

            if not mainFirst:
                for method in [posible for posible in dir(self) if ('_'+match) in posible]:
                    if getattr(self,'debug',False): print (match+' is calling self.'+method)
                    getattr(self,method)(*args, **kwargs)

                return f(self,*args,**kwargs)
            else:
                out = f(self,*args,**kwargs)

                for method in [posible for posible in dir(self) if ('_'+match) in posible]:
                    if getattr(self,'debug',False): print (match+' is calling self.'+method)
                    getattr(self,method)(*args, **kwargs)

                return out


        extra = """
            If you have things that also need to run in the method %s, you can create a method::

                def _%s*(self, ... ):
                    pass

            Where the * can be any string. If present, _%s* will be called at the start of the default %s call.
            You may also completely overwrite this function.
        """ % (match, match, match, match)
        doc = wrapper.__doc__
        wrapper.__doc__ = ('' if doc is None else doc) + extra
        return wrapper
    return callHooksWrap

def dependentProperty(name, value, children, doc):
    def fget(self): return getattr(self,name,value)
    def fset(self, val):
        if isScalar(val) and getattr(self,name,value) == val:
            return # it is the same!
        for child in children:
            if hasattr(self, child):
                delattr(self, child)
        setattr(self, name, val)
    return property(fget=fget, fset=fset, doc=doc)

def isScalar(f):
    scalarTypes = [float, int, long, np.float_, np.int_]
    if type(f) in scalarTypes:
        return True
    elif type(f) == np.ndarray and f.size == 1 and type(f[0]) in scalarTypes:
        return True
    return False

def asArray_N_x_Dim(pts, dim):
        if type(pts) == list:
            pts = np.array(pts)
        assert type(pts) == np.ndarray, "pts must be a numpy array"

        if dim > 1:
            pts = np.atleast_2d(pts)
        elif len(pts.shape) == 1:
            pts = pts[:,np.newaxis]

        assert pts.shape[1] == dim, "pts must be a column vector of shape (nPts, %d) not (%d, %d)" % ((dim,)+pts.shape)

        return pts

def requires(var):
    """
        Use this to wrap a funciton::

            @requires('prob')
            def dpred(self):
                pass

        This wrapper will ensure that a problem has been bound to the data.
        If a problem is not bound an Exception will be raised, and an nice error message printed.
    """
    def requiresVar(f):
        if var is 'prob':
            extra = """

        .. note::

            To use survey.%s(), SimPEG requires that a problem be bound to the survey.
            If a problem has not been bound, an Exception will be raised.
            To bind a problem to the Data object::

                survey.pair(myProblem)

            """ % f.__name__
        else:
            extra = """
                To use *%s* method, SimPEG requires that the %s be specified.
            """ % (f.__name__, var)
        @wraps(f)
        def requiresVarWrapper(self,*args,**kwargs):
            if getattr(self, var, None) is None:
                raise Exception(extra)
            return f(self,*args,**kwargs)

        doc = requiresVarWrapper.__doc__
        requiresVarWrapper.__doc__ = ('' if doc is None else doc) + extra

        return requiresVarWrapper
    return requiresVar