"""
basic logging functionality based on a producer/consumer scheme. 

XXX implement this API: (maybe put it into slogger.py?)

        log = Logger(
                    info=py.log.STDOUT, 
                    debug=py.log.STDOUT, 
                    command=None)
        log.info("hello", "world")
        log.command("hello", "world")

        log = Logger(info=Logger(something=...), 
                     debug=py.log.STDOUT, 
                     command=None)
"""
import py, sys

class Message(object): 
    def __init__(self, keywords, args): 
        self.keywords = keywords 
        self.args = args 

    def content(self): 
        return " ".join(map(str, self.args))

    def prefix(self): 
        return "[%s] " % (":".join(self.keywords))

    def __str__(self): 
        return self.prefix() + self.content() 


class Producer(object):
    """ (deprecated) Log producer API which sends messages to be logged
        to a 'consumer' object, which then prints them to stdout,
        stderr, files, etc. Used extensively by PyPy-1.1.
    """
    
    Message = Message  # to allow later customization 
    keywords2consumer = {}

    def __init__(self, keywords, keywordmapper=None, **kw): 
        if hasattr(keywords, 'split'):
            keywords = tuple(keywords.split())
        self._keywords = keywords
        if keywordmapper is None:
            keywordmapper = default_keywordmapper
        self._keywordmapper = keywordmapper

    def __repr__(self):
        return "<py.log.Producer %s>" % ":".join(self._keywords) 

    def __getattr__(self, name):
        if '_' in name: 
            raise AttributeError(name)
        producer = self.__class__(self._keywords + (name,))
        setattr(self, name, producer)
        return producer 
    
    def __call__(self, *args):
        """ write a message to the appropriate consumer(s) """
        func = self._keywordmapper.getconsumer(self._keywords)
        if func is not None: 
            func(self.Message(self._keywords, args))

class KeywordMapper: 
    def __init__(self):
        self.keywords2consumer = {}

    def getstate(self):
        return self.keywords2consumer.copy()
    def setstate(self, state):
        self.keywords2consumer.clear()
        self.keywords2consumer.update(state)

    def getconsumer(self, keywords):
        """ return a consumer matching the given keywords. 
        
            tries to find the most suitable consumer by walking, starting from
            the back, the list of keywords, the first consumer matching a
            keyword is returned (falling back to py.log.default)
        """
        for i in range(len(keywords), 0, -1): 
            try: 
                return self.keywords2consumer[keywords[:i]]
            except KeyError: 
                continue
        return self.keywords2consumer.get('default', default_consumer)

    def setconsumer(self, keywords, consumer): 
        """ set a consumer for a set of keywords. """ 
        # normalize to tuples 
        if isinstance(keywords, str): 
            keywords = tuple(map(None, keywords.split()))
        elif hasattr(keywords, '_keywords'): 
            keywords = keywords._keywords 
        elif not isinstance(keywords, tuple): 
            raise TypeError("key %r is not a string or tuple" % (keywords,))
        if consumer is not None and not callable(consumer): 
            if not hasattr(consumer, 'write'): 
                raise TypeError(
                    "%r should be None, callable or file-like" % (consumer,))
            consumer = File(consumer)
        self.keywords2consumer[keywords] = consumer 

def default_consumer(msg): 
    """ the default consumer, prints the message to stdout (using 'print') """
    sys.stderr.write(str(msg)+"\n")

default_keywordmapper = KeywordMapper()

def setconsumer(keywords, consumer):
    default_keywordmapper.setconsumer(keywords, consumer)

def setstate(state):
    default_keywordmapper.setstate(state)
def getstate():
    return default_keywordmapper.getstate()

#
# Consumers
#

class File(object): 
    """ log consumer wrapping a file(-like) object
    """
    def __init__(self, f): 
        assert hasattr(f, 'write')
        assert isinstance(f, file) or not hasattr(f, 'open') 
        self._file = f 

    def __call__(self, msg): 
        """ write a message to the log """
        self._file.write(str(msg) + "\n")

class Path(object): 
    """ log consumer able to write log messages into
    """
    def __init__(self, filename, append=False, delayed_create=False,
            buffering=1): 
        self._append = append
        self._filename = filename
        self._buffering = buffering
        if not delayed_create:
            self._openfile()

    def _openfile(self):
        mode = self._append and 'a' or 'w'
        f = open(str(self._filename), mode, buffering=self._buffering)
        self._file = f

    def __call__(self, msg):
        """ write a message to the log """
        if not hasattr(self, "_file"):
            self._openfile()
        self._file.write(str(msg) + "\n")

def STDOUT(msg): 
    """ consumer that writes to sys.stdout """
    sys.stdout.write(str(msg)+"\n")

def STDERR(msg): 
    """ consumer that writes to sys.stderr """
    sys.stderr.write(str(msg)+"\n")

class Syslog:
    """ consumer that writes to the syslog daemon """

    for priority in "LOG_EMERG LOG_ALERT LOG_CRIT LOG_ERR LOG_WARNING LOG_NOTICE LOG_INFO LOG_DEBUG".split():
        try:
            exec("%s = py.std.syslog.%s" % (priority, priority))
        except AttributeError:
            pass
    
    def __init__(self, priority = None):
        if priority is None:
            priority = self.LOG_INFO
        self.priority = priority

    def __call__(self, msg):
        """ write a message to the log """
        py.std.syslog.syslog(self.priority, str(msg))