#!/usr/bin/env python
"""
Kernel adapted from kernel.py to use ZMQ Streams
"""

#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------

# Standard library imports.
from __future__ import print_function
import __builtin__

import logging
import os
import sys
import time
import traceback

from code import CommandCompiler
from datetime import datetime
from pprint import pprint
from signal import SIGTERM, SIGKILL

# System library imports.
import zmq
from zmq.eventloop import ioloop, zmqstream

# Local imports.
from IPython.core import ultratb
from IPython.utils.traitlets import HasTraits, Instance, List, Int, Dict, Set, Str
from IPython.zmq.completer import KernelCompleter
from IPython.zmq.iostream import OutStream
from IPython.zmq.displayhook import DisplayHook

import heartmonitor
from client import Client
from factory import SessionFactory
from streamsession import StreamSession, Message, extract_header, serialize_object,\
                unpack_apply_message, ISO8601, wrap_exception

def printer(*args):
    pprint(args, stream=sys.__stdout__)


class _Passer:
    """Empty class that implements `send()` that does nothing."""
    def send(self, *args, **kwargs):
        pass
    send_multipart = send
    

#-----------------------------------------------------------------------------
# Main kernel class
#-----------------------------------------------------------------------------

class Kernel(SessionFactory):

    #---------------------------------------------------------------------------
    # Kernel interface
    #---------------------------------------------------------------------------
    
    # kwargs:
    int_id = Int(-1, config=True)
    user_ns = Dict(config=True)
    exec_lines = List(config=True)
    
    control_stream = Instance(zmqstream.ZMQStream)
    task_stream = Instance(zmqstream.ZMQStream)
    iopub_stream = Instance(zmqstream.ZMQStream)
    client = Instance('IPython.zmq.parallel.client.Client')
    
    # internals
    shell_streams = List()
    compiler = Instance(CommandCompiler, (), {})
    completer = Instance(KernelCompleter)
    
    aborted = Set()
    shell_handlers = Dict()
    control_handlers = Dict()
    
    def _set_prefix(self):
        self.prefix = "engine.%s"%self.int_id
    
    def _connect_completer(self):
        self.completer = KernelCompleter(self.user_ns)
    
    def __init__(self, **kwargs):
        super(Kernel, self).__init__(**kwargs)
        self._set_prefix()
        self._connect_completer()
        
        self.on_trait_change(self._set_prefix, 'id')
        self.on_trait_change(self._connect_completer, 'user_ns')
        
        # Build dict of handlers for message types
        for msg_type in ['execute_request', 'complete_request', 'apply_request', 
                'clear_request']:
            self.shell_handlers[msg_type] = getattr(self, msg_type)
        
        for msg_type in ['shutdown_request', 'abort_request']+self.shell_handlers.keys():
            self.control_handlers[msg_type] = getattr(self, msg_type)
        
        self._initial_exec_lines()
    
    def _wrap_exception(self, method=None):
        e_info = dict(engineid=self.ident, method=method)
        content=wrap_exception(e_info)
        return content
    
    def _initial_exec_lines(self):
        s = _Passer()
        content = dict(silent=True, user_variable=[],user_expressions=[])
        for line in self.exec_lines:
            self.log.debug("executing initialization: %s"%line)
            content.update({'code':line})
            msg = self.session.msg('execute_request', content)
            self.execute_request(s, [], msg)
        
        
    #-------------------- control handlers -----------------------------
    def abort_queues(self):
        for stream in self.shell_streams:
            if stream:
                self.abort_queue(stream)
    
    def abort_queue(self, stream):
        while True:
            try:
                msg = self.session.recv(stream, zmq.NOBLOCK,content=True)
            except zmq.ZMQError as e:
                if e.errno == zmq.EAGAIN:
                    break
                else:
                    return
            else:
                if msg is None:
                    return
                else:
                    idents,msg = msg
                
                # assert self.reply_socketly_socket.rcvmore(), "Unexpected missing message part."
                # msg = self.reply_socket.recv_json()
            self.log.info("Aborting:")
            self.log.info(str(msg))
            msg_type = msg['msg_type']
            reply_type = msg_type.split('_')[0] + '_reply'
            # reply_msg = self.session.msg(reply_type, {'status' : 'aborted'}, msg)
            # self.reply_socket.send(ident,zmq.SNDMORE)
            # self.reply_socket.send_json(reply_msg)
            reply_msg = self.session.send(stream, reply_type, 
                        content={'status' : 'aborted'}, parent=msg, ident=idents)[0]
            self.log.debug(str(reply_msg))
            # We need to wait a bit for requests to come in. This can probably
            # be set shorter for true asynchronous clients.
            time.sleep(0.05)
    
    def abort_request(self, stream, ident, parent):
        """abort a specifig msg by id"""
        msg_ids = parent['content'].get('msg_ids', None)
        if isinstance(msg_ids, basestring):
            msg_ids = [msg_ids]
        if not msg_ids:
            self.abort_queues()
        for mid in msg_ids:
            self.aborted.add(str(mid))
        
        content = dict(status='ok')
        reply_msg = self.session.send(stream, 'abort_reply', content=content, 
                parent=parent, ident=ident)[0]
        self.log.debug(str(reply_msg))
    
    def shutdown_request(self, stream, ident, parent):
        """kill ourself.  This should really be handled in an external process"""
        try:
            self.abort_queues()
        except:
            content = self._wrap_exception('shutdown')
        else:
            content = dict(parent['content'])
            content['status'] = 'ok'
        msg = self.session.send(stream, 'shutdown_reply',
                                content=content, parent=parent, ident=ident)
        # msg = self.session.send(self.pub_socket, 'shutdown_reply',
        #                         content, parent, ident)
        # print >> sys.__stdout__, msg
        # time.sleep(0.2)
        dc = ioloop.DelayedCallback(lambda : sys.exit(0), 1000, self.loop)
        dc.start()
    
    def dispatch_control(self, msg):
        idents,msg = self.session.feed_identities(msg, copy=False)
        try:
            msg = self.session.unpack_message(msg, content=True, copy=False)
        except:
            self.log.error("Invalid Message", exc_info=True)
            return
        
        header = msg['header']
        msg_id = header['msg_id']
        
        handler = self.control_handlers.get(msg['msg_type'], None)
        if handler is None:
            self.log.error("UNKNOWN CONTROL MESSAGE TYPE: %r"%msg['msg_type'])
        else:
            handler(self.control_stream, idents, msg)
    

    #-------------------- queue helpers ------------------------------
    
    def check_dependencies(self, dependencies):
        if not dependencies:
            return True
        if len(dependencies) == 2 and dependencies[0] in 'any all'.split():
            anyorall = dependencies[0]
            dependencies = dependencies[1]
        else:
            anyorall = 'all'
        results = self.client.get_results(dependencies,status_only=True)
        if results['status'] != 'ok':
            return False
        
        if anyorall == 'any':
            if not results['completed']:
                return False
        else:
            if results['pending']:
                return False
        
        return True
    
    def check_aborted(self, msg_id):
        return msg_id in self.aborted
    
    #-------------------- queue handlers -----------------------------
    
    def clear_request(self, stream, idents, parent):
        """Clear our namespace."""
        self.user_ns = {}
        msg = self.session.send(stream, 'clear_reply', ident=idents, parent=parent, 
                content = dict(status='ok'))
        self._initial_exec_lines()
    
    def execute_request(self, stream, ident, parent):
        self.log.debug('execute request %s'%parent)
        try:
            code = parent[u'content'][u'code']
        except:
            self.log.error("Got bad msg: %s"%parent, exc_info=True)
            return
        self.session.send(self.iopub_stream, u'pyin', {u'code':code},parent=parent,
                            ident='%s.pyin'%self.prefix)
        started = datetime.now().strftime(ISO8601)
        try:
            comp_code = self.compiler(code, '<zmq-kernel>')
            # allow for not overriding displayhook
            if hasattr(sys.displayhook, 'set_parent'):
                sys.displayhook.set_parent(parent)
                sys.stdout.set_parent(parent)
                sys.stderr.set_parent(parent)
            exec comp_code in self.user_ns, self.user_ns
        except:
            exc_content = self._wrap_exception('execute')
            # exc_msg = self.session.msg(u'pyerr', exc_content, parent)
            self.session.send(self.iopub_stream, u'pyerr', exc_content, parent=parent,
                            ident='%s.pyerr'%self.prefix)
            reply_content = exc_content
        else:
            reply_content = {'status' : 'ok'}
        
        reply_msg = self.session.send(stream, u'execute_reply', reply_content, parent=parent, 
                    ident=ident, subheader = dict(started=started))
        self.log.debug(str(reply_msg))
        if reply_msg['content']['status'] == u'error':
            self.abort_queues()

    def complete_request(self, stream, ident, parent):
        matches = {'matches' : self.complete(parent),
                   'status' : 'ok'}
        completion_msg = self.session.send(stream, 'complete_reply',
                                           matches, parent, ident)
        # print >> sys.__stdout__, completion_msg

    def complete(self, msg):
        return self.completer.complete(msg.content.line, msg.content.text)
    
    def apply_request(self, stream, ident, parent):
        # flush previous reply, so this request won't block it
        stream.flush(zmq.POLLOUT)
        
        try:
            content = parent[u'content']
            bufs = parent[u'buffers']
            msg_id = parent['header']['msg_id']
            bound = content.get('bound', False)
        except:
            self.log.error("Got bad msg: %s"%parent, exc_info=True)
            return
        # pyin_msg = self.session.msg(u'pyin',{u'code':code}, parent=parent)
        # self.iopub_stream.send(pyin_msg)
        # self.session.send(self.iopub_stream, u'pyin', {u'code':code},parent=parent)
        sub = {'dependencies_met' : True, 'engine' : self.ident,
                'started': datetime.now().strftime(ISO8601)}
        try:
            # allow for not overriding displayhook
            if hasattr(sys.displayhook, 'set_parent'):
                sys.displayhook.set_parent(parent)
                sys.stdout.set_parent(parent)
                sys.stderr.set_parent(parent)
            # exec "f(*args,**kwargs)" in self.user_ns, self.user_ns
            if bound:
                working = self.user_ns
                suffix = str(msg_id).replace("-","")
                prefix = "_"
                
            else:
                working = dict()
                suffix = prefix = "_" # prevent keyword collisions with lambda
            f,args,kwargs = unpack_apply_message(bufs, working, copy=False)
            # if f.fun
            fname = getattr(f, '__name__', 'f')
            
            fname = prefix+fname.strip('<>')+suffix
            argname = prefix+"args"+suffix
            kwargname = prefix+"kwargs"+suffix
            resultname = prefix+"result"+suffix
            
            ns = { fname : f, argname : args, kwargname : kwargs }
            # print ns
            working.update(ns)
            code = "%s=%s(*%s,**%s)"%(resultname, fname, argname, kwargname)
            exec code in working, working
            result = working.get(resultname)
            # clear the namespace
            if bound:
                for key in ns.iterkeys():
                    self.user_ns.pop(key)
            else:
                del working
            
            packed_result,buf = serialize_object(result)
            result_buf = [packed_result]+buf
        except:
            exc_content = self._wrap_exception('apply')
            # exc_msg = self.session.msg(u'pyerr', exc_content, parent)
            self.session.send(self.iopub_stream, u'pyerr', exc_content, parent=parent,
                                ident='%s.pyerr'%self.prefix)
            reply_content = exc_content
            result_buf = []
            
            if exc_content['ename'] == 'UnmetDependency':
                sub['dependencies_met'] = False
        else:
            reply_content = {'status' : 'ok'}
        
        # put 'ok'/'error' status in header, for scheduler introspection:
        sub['status'] = reply_content['status']
        
        reply_msg = self.session.send(stream, u'apply_reply', reply_content, 
                    parent=parent, ident=ident,buffers=result_buf, subheader=sub)

        # if reply_msg['content']['status'] == u'error':
        #     self.abort_queues()
    
    def dispatch_queue(self, stream, msg):
        self.control_stream.flush()
        idents,msg = self.session.feed_identities(msg, copy=False)
        try:
            msg = self.session.unpack_message(msg, content=True, copy=False)
        except:
            self.log.error("Invalid Message", exc_info=True)
            return
            
        
        header = msg['header']
        msg_id = header['msg_id']
        if self.check_aborted(msg_id):
            self.aborted.remove(msg_id)
            # is it safe to assume a msg_id will not be resubmitted?
            reply_type = msg['msg_type'].split('_')[0] + '_reply'
            reply_msg = self.session.send(stream, reply_type, 
                        content={'status' : 'aborted'}, parent=msg, ident=idents)
            return
        handler = self.shell_handlers.get(msg['msg_type'], None)
        if handler is None:
            self.log.error("UNKNOWN MESSAGE TYPE: %r"%msg['msg_type'])
        else:
            handler(stream, idents, msg)
    
    def start(self):
        #### stream mode:
        if self.control_stream:
            self.control_stream.on_recv(self.dispatch_control, copy=False)
            self.control_stream.on_err(printer)
        
        def make_dispatcher(stream):
            def dispatcher(msg):
                return self.dispatch_queue(stream, msg)
            return dispatcher
        
        for s in self.shell_streams:
            s.on_recv(make_dispatcher(s), copy=False)
            s.on_err(printer)
        
        if self.iopub_stream:
            self.iopub_stream.on_err(printer)
        
        #### while True mode:
        # while True:
        #     idle = True
        #     try:
        #         msg = self.shell_stream.socket.recv_multipart(
        #                     zmq.NOBLOCK, copy=False)
        #     except zmq.ZMQError, e:
        #         if e.errno != zmq.EAGAIN:
        #             raise e
        #     else:
        #         idle=False
        #         self.dispatch_queue(self.shell_stream, msg)
        #             
        #     if not self.task_stream.empty():
        #         idle=False
        #         msg = self.task_stream.recv_multipart()
        #         self.dispatch_queue(self.task_stream, msg)
        #     if idle:
        #         # don't busywait
        #         time.sleep(1e-3)

def make_kernel(int_id, identity, control_addr, shell_addrs, iopub_addr, hb_addrs, 
                client_addr=None, loop=None, context=None, key=None,
                out_stream_factory=OutStream, display_hook_factory=DisplayHook):
    """NO LONGER IN USE"""
    # create loop, context, and session:
    if loop is None:
        loop = ioloop.IOLoop.instance()
    if context is None:
        context = zmq.Context()
    c = context
    session = StreamSession(key=key)
    # print (session.key)
    # print (control_addr, shell_addrs, iopub_addr, hb_addrs)
    
    # create Control Stream
    control_stream = zmqstream.ZMQStream(c.socket(zmq.PAIR), loop)
    control_stream.setsockopt(zmq.IDENTITY, identity)
    control_stream.connect(control_addr)
    
    # create Shell Streams (MUX, Task, etc.):
    shell_streams = []
    for addr in shell_addrs:
        stream = zmqstream.ZMQStream(c.socket(zmq.PAIR), loop)
        stream.setsockopt(zmq.IDENTITY, identity)
        stream.connect(addr)
        shell_streams.append(stream)
    
    # create iopub stream:
    iopub_stream = zmqstream.ZMQStream(c.socket(zmq.PUB), loop)
    iopub_stream.setsockopt(zmq.IDENTITY, identity)
    iopub_stream.connect(iopub_addr)
    
    # Redirect input streams and set a display hook.
    if out_stream_factory:
        sys.stdout = out_stream_factory(session, iopub_stream, u'stdout')
        sys.stdout.topic = 'engine.%i.stdout'%int_id
        sys.stderr = out_stream_factory(session, iopub_stream, u'stderr')
        sys.stderr.topic = 'engine.%i.stderr'%int_id
    if display_hook_factory:
        sys.displayhook = display_hook_factory(session, iopub_stream)
        sys.displayhook.topic = 'engine.%i.pyout'%int_id
    
    
    # launch heartbeat
    heart = heartmonitor.Heart(*map(str, hb_addrs), heart_id=identity)
    heart.start()
    
    # create (optional) Client
    if client_addr:
        client = Client(client_addr, username=identity)
    else:
        client = None
    
    kernel = Kernel(id=int_id, session=session, control_stream=control_stream,
            shell_streams=shell_streams, iopub_stream=iopub_stream, 
            client=client, loop=loop)
    kernel.start()
    return loop, c, kernel