import __builtin__
import sys

__all__ = ['describeException', 'pdir']

# class 'decorator' that records the stack at the time of creation
# be careful with this, it creates a StackTrace, and that can take a
# lot of CPU
def recordCreationStack(cls):
    if not hasattr(cls, '__init__'):
        raise 'recordCreationStack: class \'%s\' must define __init__' % cls.__name__
    cls.__moved_init__ = cls.__init__
    def __recordCreationStack_init__(self, *args, **kArgs):
        self._creationStackTrace = StackTrace(start=1)
        return self.__moved_init__(*args, **kArgs)
    def getCreationStackTrace(self):
        return self._creationStackTrace
    def getCreationStackTraceCompactStr(self):
        return self._creationStackTrace.compact()
    def printCreationStackTrace(self):
        print self._creationStackTrace
    cls.__init__ = __recordCreationStack_init__
    cls.getCreationStackTrace = getCreationStackTrace
    cls.getCreationStackTraceCompactStr = getCreationStackTraceCompactStr
    cls.printCreationStackTrace = printCreationStackTrace
    return cls

def describeException(backTrace = 4):
    # When called in an exception handler, returns a string describing
    # the current exception.

    def byteOffsetToLineno(code, byte):
        # Returns the source line number corresponding to the given byte
        # offset into the indicated Python code module.

        import array
        lnotab = array.array('B', code.co_lnotab)

        line   = code.co_firstlineno
        for i in range(0, len(lnotab), 2):
            byte -= lnotab[i]
            if byte <= 0:
                return line
            line += lnotab[i+1]

        return line

    infoArr = sys.exc_info()
    exception = infoArr[0]
    exceptionName = getattr(exception, '__name__', None)
    extraInfo = infoArr[1]
    trace = infoArr[2]

    stack = []
    while trace.tb_next:
        # We need to call byteOffsetToLineno to determine the true
        # line number at which the exception occurred, even though we
        # have both trace.tb_lineno and frame.f_lineno, which return
        # the correct line number only in non-optimized mode.
        frame = trace.tb_frame
        module = frame.f_globals.get('__name__', None)
        lineno = byteOffsetToLineno(frame.f_code, frame.f_lasti)
        stack.append("%s:%s, " % (module, lineno))
        trace = trace.tb_next

    frame = trace.tb_frame
    module = frame.f_globals.get('__name__', None)
    lineno = byteOffsetToLineno(frame.f_code, frame.f_lasti)
    stack.append("%s:%s, " % (module, lineno))

    description = ""
    for i in range(len(stack) - 1, max(len(stack) - backTrace, 0) - 1, -1):
        description += stack[i]

    description += "%s: %s" % (exceptionName, extraInfo)
    return description

def pdir(obj, str = None, width = None,
            fTruncate = 1, lineWidth = 75, wantPrivate = 0):
    # Remove redundant class entries
    uniqueLineage = []
    for l in getClassLineage(obj):
        if type(l) == types.ClassType:
            if l in uniqueLineage:
                break
        uniqueLineage.append(l)
    # Pretty print out directory info
    uniqueLineage.reverse()
    for obj in uniqueLineage:
        _pdir(obj, str, width, fTruncate, lineWidth, wantPrivate)
        print

def quantize(value, divisor):
    # returns new value that is multiple of (1. / divisor)
    return float(int(value * int(divisor))) / int(divisor)

def quantizeVec(vec, divisor):
    # in-place
    vec[0] = quantize(vec[0], divisor)
    vec[1] = quantize(vec[1], divisor)
    vec[2] = quantize(vec[2], divisor)

def isClient():
    if hasattr(__builtin__, 'simbase') and not hasattr(__builtin__, 'base'):
        return False
    return True


__builtin__.pdir = pdir
__builtin__.isClient = isClient