# -*- coding: utf-8 -*-
"""terminal client to the IPython kernel"""

# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.

from __future__ import print_function

import base64
import bdb
import errno
import signal
import os
import sys
import time
import subprocess
from getpass import getpass
from io import BytesIO

try:
    from queue import Empty  # Py 3
except ImportError:
    from Queue import Empty  # Py 2

from zmq import ZMQError

from IPython.core import page
from jupyter_console.zmqhistory import ZMQHistoryManager
from IPython.utils.warn import warn, error
from IPython.utils import io
from ipython_genutils.py3compat import string_types, input
from traitlets import List, Enum, Any, Instance, Unicode, Float, Bool
from ipython_genutils.tempdir import NamedFileInTemporaryDirectory

from IPython.terminal.interactiveshell import TerminalInteractiveShell
from jupyter_console.completer import ZMQCompleter
from jupyter_console import __version__

class ZMQTerminalInteractiveShell(TerminalInteractiveShell):
    """A subclass of TerminalInteractiveShell that uses the 0MQ kernel"""
    _executing = False
    _execution_state = Unicode('')
    _pending_clearoutput = False
    kernel_banner = Unicode('')
    kernel_timeout = Float(60, config=True,
        help="""Timeout for giving up on a kernel (in seconds).

        On first connect and restart, the console tests whether the
        kernel is running and responsive by sending kernel_info_requests.
        This sets the timeout in seconds for how long the kernel can take
        before being presumed dead.
        """
    )

    image_handler = Enum(('PIL', 'stream', 'tempfile', 'callable'),
                         config=True, allow_none=True, help=
        """
        Handler for image type output.  This is useful, for example,
        when connecting to the kernel in which pylab inline backend is
        activated.  There are four handlers defined.  'PIL': Use
        Python Imaging Library to popup image; 'stream': Use an
        external program to show the image.  Image will be fed into
        the STDIN of the program.  You will need to configure
        `stream_image_handler`; 'tempfile': Use an external program to
        show the image.  Image will be saved in a temporally file and
        the program is called with the temporally file.  You will need
        to configure `tempfile_image_handler`; 'callable': You can set
        any Python callable which is called with the image data.  You
        will need to configure `callable_image_handler`.
        """
    )

    stream_image_handler = List(config=True, help=
        """
        Command to invoke an image viewer program when you are using
        'stream' image handler.  This option is a list of string where
        the first element is the command itself and reminders are the
        options for the command.  Raw image data is given as STDIN to
        the program.
        """
    )

    tempfile_image_handler = List(config=True, help=
        """
        Command to invoke an image viewer program when you are using
        'tempfile' image handler.  This option is a list of string
        where the first element is the command itself and reminders
        are the options for the command.  You can use {file} and
        {format} in the string to represent the location of the
        generated image file and image format.
        """
    )

    callable_image_handler = Any(config=True, help=
        """
        Callable object called via 'callable' image handler with one
        argument, `data`, which is `msg["content"]["data"]` where
        `msg` is the message from iopub channel.  For exmaple, you can
        find base64 encoded PNG data as `data['image/png']`.
        """
    )

    mime_preference = List(
        default_value=['image/png', 'image/jpeg', 'image/svg+xml'],
        config=True, help=
        """
        Preferred object representation MIME type in order.  First
        matched MIME type will be used.
        """
    )

    use_kernel_is_complete = Bool(True, config=True,
        help="""Whether to use the kernel's is_complete message
        handling. If False, then the frontend will use its
        own is_complete handler.
        """
    )
    kernel_is_complete_timeout = Float(1, config=True,
        help="""Timeout (in seconds) for giving up on a kernel's is_complete
        response.

        If the kernel does not respond at any point within this time,
        the kernel will no longer be asked if code is complete, and the
        console will default to the built-in is_complete test.
        """
    )

    manager = Instance('jupyter_client.KernelManager', allow_none=True)
    client = Instance('jupyter_client.KernelClient', allow_none=True)
    def _client_changed(self, name, old, new):
        self.session_id = new.session.session
    session_id = Unicode()

    def __init__(self, *args, **kwargs):
        super(ZMQTerminalInteractiveShell, self).__init__(*args, **kwargs)
        self._source_lines_buffered = []

    def init_completer(self):
        """Initialize the completion machinery.

        This creates completion machinery that can be used by client code,
        either interactively in-process (typically triggered by the readline
        library), programmatically (such as in test suites) or out-of-process
        (typically over the network by remote frontends).
        """
        from IPython.core.completerlib import (module_completer,
                                               magic_run_completer, cd_completer)

        self.Completer = ZMQCompleter(self, self.client, config=self.config)


        self.set_hook('complete_command', module_completer, str_key = 'import')
        self.set_hook('complete_command', module_completer, str_key = 'from')
        self.set_hook('complete_command', magic_run_completer, str_key = '%run')
        self.set_hook('complete_command', cd_completer, str_key = '%cd')

        # Only configure readline if we truly are using readline.  IPython can
        # do tab-completion over the network, in GUIs, etc, where readline
        # itself may be absent
        if self.has_readline:
            self.set_readline_completer()

    def run_cell(self, cell, store_history=True):
        """Run a complete IPython cell.

        Parameters
        ----------
        cell : str
          The code (including IPython code such as %magic functions) to run.
        store_history : bool
          If True, the raw and translated cell will be stored in IPython's
          history. For user code calling back into IPython's machinery, this
          should be set to False.
        """
        if (not cell) or cell.isspace():
            # pressing enter flushes any pending display
            self.handle_iopub()
            return

        # flush stale replies, which could have been ignored, due to missed heartbeats
        while self.client.shell_channel.msg_ready():
            self.client.shell_channel.get_msg()
        # execute takes 'hidden', which is the inverse of store_hist
        msg_id = self.client.execute(cell, not store_history)

        # first thing is wait for any side effects (output, stdin, etc.)
        self._executing = True
        self._execution_state = "busy"
        while self._execution_state != 'idle' and self.client.is_alive():
            try:
                self.handle_input_request(msg_id, timeout=0.05)
            except Empty:
                # display intermediate print statements, etc.
                self.handle_iopub(msg_id)
            except ZMQError as e:
                # Carry on if polling was interrupted by a signal
                if e.errno != errno.EINTR:
                    raise

        # after all of that is done, wait for the execute reply
        while self.client.is_alive():
            try:
                self.handle_execute_reply(msg_id, timeout=0.05)
            except Empty:
                pass
            else:
                break
        self._executing = False

    #-----------------
    # message handlers
    #-----------------

    def handle_execute_reply(self, msg_id, timeout=None):
        msg = self.client.shell_channel.get_msg(block=False, timeout=timeout)
        if msg["parent_header"].get("msg_id", None) == msg_id:

            self.handle_iopub(msg_id)

            content = msg["content"]
            status = content['status']

            if status == 'aborted':
                self.write('Aborted\n')
                return
            elif status == 'ok':
                # handle payloads
                for item in content.get("payload", []):
                    source = item['source']
                    if source == 'page':
                        page.page(item['data']['text/plain'])
                    elif source == 'set_next_input':
                        self.set_next_input(item['text'])
                    elif source == 'ask_exit':
                        self.keepkernel = item.get('keepkernel', False)
                        self.ask_exit()

            elif status == 'error':
                pass

            self.execution_count = int(content["execution_count"] + 1)

    def handle_is_complete_reply(self, msg_id, timeout=None):
        """
        Wait for a repsonse from the kernel, and return two values:
            more? - (boolean) should the frontend ask for more input
            indent - an indent string to prefix the input
        Overloaded methods may want to examine the comeplete source. Its is
        in the self._source_lines_buffered list.
        """
        ## Get the is_complete response:
        msg = None
        try:
            msg = self.client.shell_channel.get_msg(block=True, timeout=timeout)
        except Empty:
            warn('The kernel did not respond to an is_complete_request. '
                 'Setting `use_kernel_is_complete` to False.')
            self.use_kernel_is_complete = False
            return False, ""
        ## Handle response:
        if msg["parent_header"].get("msg_id", None) != msg_id:
            warn('The kernel did not respond properly to an is_complete_request: %s.' % str(msg))
            return False, ""
        else:
            status = msg["content"].get("status", None)
            indent = msg["content"].get("indent", "")
        ## Return more? and indent string
        if status == "complete":
            return False, indent
        elif status == "incomplete":
            return True, indent
        elif status == "invalid":
            raise SyntaxError()
        elif status == "unknown":
            return False, indent
        else:
            warn('The kernel sent an invalid is_complete_reply status: "%s".' % status)
            return False, indent

    include_other_output = Bool(False, config=True,
        help="""Whether to include output from clients
        other than this one sharing the same kernel.

        Outputs are not displayed until enter is pressed.
        """
    )
    other_output_prefix = Unicode("[remote] ", config=True,
        help="""Prefix to add to outputs coming from clients other than this one.

        Only relevant if include_other_output is True.
        """
    )

    def from_here(self, msg):
        """Return whether a message is from this session"""
        return msg['parent_header'].get("session", self.session_id) == self.session_id

    def include_output(self, msg):
        """Return whether we should include a given output message"""
        from_here = self.from_here(msg)
        if msg['msg_type'] == 'execute_input':
            # only echo inputs not from here
            return self.include_other_output and not from_here

        if self.include_other_output:
            return True
        else:
            return from_here

    def handle_iopub(self, msg_id=''):
        """Process messages on the IOPub channel

           This method consumes and processes messages on the IOPub channel,
           such as stdout, stderr, execute_result and status.

           It only displays output that is caused by this session.
        """
        while self.client.iopub_channel.msg_ready():
            sub_msg = self.client.iopub_channel.get_msg()
            msg_type = sub_msg['header']['msg_type']
            parent = sub_msg["parent_header"]

            if self.include_output(sub_msg):
                if msg_type == 'status':
                    self._execution_state = sub_msg["content"]["execution_state"]
                elif msg_type == 'stream':
                    if sub_msg["content"]["name"] == "stdout":
                        if self._pending_clearoutput:
                            print("\r", file=io.stdout, end="")
                            self._pending_clearoutput = False
                        print(sub_msg["content"]["text"], file=io.stdout, end="")
                        io.stdout.flush()
                    elif sub_msg["content"]["name"] == "stderr":
                        if self._pending_clearoutput:
                            print("\r", file=io.stderr, end="")
                            self._pending_clearoutput = False
                        print(sub_msg["content"]["text"], file=io.stderr, end="")
                        io.stderr.flush()

                elif msg_type == 'execute_result':
                    if self._pending_clearoutput:
                        print("\r", file=io.stdout, end="")
                        self._pending_clearoutput = False
                    self.execution_count = int(sub_msg["content"]["execution_count"])
                    if not self.from_here(sub_msg):
                        sys.stdout.write(self.other_output_prefix)
                    format_dict = sub_msg["content"]["data"]
                    self.handle_rich_data(format_dict)

                    # taken from DisplayHook.__call__:
                    hook = self.displayhook
                    hook.start_displayhook()
                    hook.write_output_prompt()
                    hook.write_format_data(format_dict)
                    hook.log_output(format_dict)
                    hook.finish_displayhook()

                elif msg_type == 'display_data':
                    data = sub_msg["content"]["data"]
                    handled = self.handle_rich_data(data)
                    if not handled:
                        if not self.from_here(sub_msg):
                            sys.stdout.write(self.other_output_prefix)
                        # if it was an image, we handled it by now
                        if 'text/plain' in data:
                            print(data['text/plain'])

                elif msg_type == 'execute_input':
                    content = sub_msg['content']
                    self.execution_count = content['execution_count']
                    if not self.from_here(sub_msg):
                        sys.stdout.write(self.other_output_prefix)
                    sys.stdout.write(self.prompt_manager.render('in'))
                    sys.stdout.write(content['code'])

                elif msg_type == 'clear_output':
                    if sub_msg["content"]["wait"]:
                        self._pending_clearoutput = True
                    else:
                        print("\r", file=io.stdout, end="")

                elif msg_type == 'error':
                    for frame in sub_msg["content"]["traceback"]:
                        print(frame, file=io.stderr)


    _imagemime = {
        'image/png': 'png',
        'image/jpeg': 'jpeg',
        'image/svg+xml': 'svg',
    }

    def handle_rich_data(self, data):
        for mime in self.mime_preference:
            if mime in data and mime in self._imagemime:
                self.handle_image(data, mime)
                return True

    def handle_image(self, data, mime):
        handler = getattr(
            self, 'handle_image_{0}'.format(self.image_handler), None)
        if handler:
            handler(data, mime)

    def handle_image_PIL(self, data, mime):
        if mime not in ('image/png', 'image/jpeg'):
            return
        import PIL.Image
        raw = base64.decodestring(data[mime].encode('ascii'))
        img = PIL.Image.open(BytesIO(raw))
        img.show()

    def handle_image_stream(self, data, mime):
        raw = base64.decodestring(data[mime].encode('ascii'))
        imageformat = self._imagemime[mime]
        fmt = dict(format=imageformat)
        args = [s.format(**fmt) for s in self.stream_image_handler]
        with open(os.devnull, 'w') as devnull:
            proc = subprocess.Popen(
                args, stdin=subprocess.PIPE,
                stdout=devnull, stderr=devnull)
            proc.communicate(raw)

    def handle_image_tempfile(self, data, mime):
        raw = base64.decodestring(data[mime].encode('ascii'))
        imageformat = self._imagemime[mime]
        filename = 'tmp.{0}'.format(imageformat)
        with NamedFileInTemporaryDirectory(filename) as f, \
                    open(os.devnull, 'w') as devnull:
            f.write(raw)
            f.flush()
            fmt = dict(file=f.name, format=imageformat)
            args = [s.format(**fmt) for s in self.tempfile_image_handler]
            subprocess.call(args, stdout=devnull, stderr=devnull)

    def handle_image_callable(self, data, mime):
        self.callable_image_handler(data)

    def handle_input_request(self, msg_id, timeout=0.1):
        """ Method to capture raw_input
        """
        req = self.client.stdin_channel.get_msg(timeout=timeout)
        # in case any iopub came while we were waiting:
        self.handle_iopub(msg_id)
        if msg_id == req["parent_header"].get("msg_id"):
            # wrap SIGINT handler
            real_handler = signal.getsignal(signal.SIGINT)
            def double_int(sig,frame):
                # call real handler (forwards sigint to kernel),
                # then raise local interrupt, stopping local raw_input
                real_handler(sig,frame)
                raise KeyboardInterrupt
            signal.signal(signal.SIGINT, double_int)
            content = req['content']
            read = getpass if content.get('password', False) else input
            if self.has_readline:
                # Disable tab completion while we prompt for arbitrary input
                self.readline.set_completer(None)
            try:
                raw_data = read(content["prompt"])
            except EOFError:
                # turn EOFError into EOF character
                raw_data = '\x04'
            except KeyboardInterrupt:
                sys.stdout.write('\n')
                return
            finally:
                # restore SIGINT handler
                signal.signal(signal.SIGINT, real_handler)
                # Restore tab completion ready for our next input prompt
                if self.has_readline:
                    self.set_readline_completer()

            # only send stdin reply if there *was not* another request
            # or execution finished while we were reading.
            if not (self.client.stdin_channel.msg_ready() or self.client.shell_channel.msg_ready()):
                self.client.input(raw_data)

    def mainloop(self, display_banner=False):
        self.keepkernel = False
        while True:
            try:
                self.interact(display_banner=display_banner)
                #self.interact_with_readline()
                # XXX for testing of a readline-decoupled repl loop, call
                # interact_with_readline above
                break
            except KeyboardInterrupt:
                # this should not be necessary, but KeyboardInterrupt
                # handling seems rather unpredictable...
                self.write("\nKeyboardInterrupt in interact()\n")

        if self.keepkernel and not self.own_kernel:
            print('keeping kernel alive')
        elif self.keepkernel and self.own_kernel :
            print("owning kernel, cannot keep it alive")
            self.client.shutdown()
        else :
            print("Shutting down kernel")
            self.client.shutdown()

    def _banner1_default(self):
        return "Jupyter Console {version}\n".format(version=__version__)

    def compute_banner(self):
        super(ZMQTerminalInteractiveShell, self).compute_banner()
        if self.client and not self.kernel_banner:
            msg_id = self.client.kernel_info()
            while True:
                try:
                    reply = self.client.get_shell_msg(timeout=1)
                except Empty:
                    break
                else:
                    if reply['parent_header'].get('msg_id') == msg_id:
                        self.kernel_banner = reply['content'].get('banner', '')
                        break
        self.banner += self.kernel_banner

    def wait_for_kernel(self, timeout=None):
        """method to wait for a kernel to be ready"""
        tic = time.time()
        self.client.hb_channel.unpause()
        while True:
            msg_id = self.client.kernel_info()
            reply = None
            while True:
                try:
                    reply = self.client.get_shell_msg(timeout=1)
                except Empty:
                    break
                else:
                    if reply['parent_header'].get('msg_id') == msg_id:
                        return True
            if timeout is not None \
                and (time.time() - tic) > timeout \
                and not self.client.hb_channel.is_beating():
                # heart failed
                return False
        return True

    _next_line_indent = ''

    def _indent_current_str(self):
        return self._next_line_indent

    def interact(self, display_banner=None):
        """Closely emulate the interactive Python console."""

        # batch run -> do not interact
        if self.exit_now:
            return

        if display_banner is None:
            display_banner = self.display_banner

        if isinstance(display_banner, string_types):
            self.show_banner(display_banner)
        elif display_banner:
            self.show_banner()

        more = False

        # run a non-empty no-op, so that we don't get a prompt until
        # we know the kernel is ready. This keeps the connection
        # message above the first prompt.
        if not self.wait_for_kernel(self.kernel_timeout):
            error("Kernel did not respond\n")
            return

        if self.has_readline:
            self.readline_startup_hook(self.pre_readline)
            hlen_b4_cell = self.readline.get_current_history_length()
            self.refill_readline_hist()
        else:
            hlen_b4_cell = 0
        # exit_now is set by a call to %Exit or %Quit, through the
        # ask_exit callback.

        while not self.exit_now:
            if not self.client.is_alive():
                # kernel died, prompt for action or exit

                action = "restart" if self.manager else "wait for restart"
                ans = self.ask_yes_no("kernel died, %s ([y]/n)?" % action, default='y')
                if ans:
                    if self.manager:
                        self.manager.restart_kernel(True)
                    self.wait_for_kernel(self.kernel_timeout)
                else:
                    self.exit_now = True
                continue
            try:
                # protect prompt block from KeyboardInterrupt
                # when sitting on ctrl-C
                self.hooks.pre_prompt_hook()
                if more:
                    try:
                        prompt = self.prompt_manager.render('in2')
                    except Exception:
                        self.showtraceback()
                    if self.autoindent:
                        self.rl_do_indent = True

                else:
                    self._next_line_indent = ''
                    try:
                        prompt = self.separate_in + self.prompt_manager.render('in')
                    except Exception:
                        self.showtraceback()

                line = self.raw_input(prompt)
                if self.exit_now:
                    # quick exit on sys.std[in|out] close
                    break
                if self.autoindent:
                    self.rl_do_indent = False

            except KeyboardInterrupt:
                #double-guard against keyboardinterrupts during kbdint handling
                try:
                    self.write('\n' + self.get_exception_only())
                    source_raw = self.get_source_and_reset()
                    hlen_b4_cell = self._replace_rlhist_multiline(source_raw, hlen_b4_cell)
                    more = False
                except KeyboardInterrupt:
                    pass
            except EOFError:
                if self.autoindent:
                    self.rl_do_indent = False
                    if self.has_readline:
                        self.readline_startup_hook(None)
                self.write('\n')
                self.exit()
            except bdb.BdbQuit:
                warn('The Python debugger has exited with a BdbQuit exception.\n'
                     'Because of how pdb handles the stack, it is impossible\n'
                     'for IPython to properly format this particular exception.\n'
                     'IPython will resume normal operation.')
            except:
                # exceptions here are VERY RARE, but they can be triggered
                # asynchronously by signal handlers, for example.
                self.showtraceback()
            else:
                try:
                    more, indent = self.handle_source(line)
                except SyntaxError:
                    # Run the code directly - run_cell takes care of displaying
                    # the exception.
                    more = False
                if (self.SyntaxTB.last_syntax_error and
                    self.autoedit_syntax):
                    self.edit_syntax_error()
                if more:
                    self._next_line_indent = indent
                if not more:
                    source_raw = self.get_source_and_reset()
                    hlen_b4_cell = self._replace_rlhist_multiline(source_raw, hlen_b4_cell)
                    self.run_cell(source_raw)


        # Turn off the exit flag, so the mainloop can be restarted if desired
        self.exit_now = False

    def init_history(self):
        """Sets up the command history. """
        self.history_manager = ZMQHistoryManager(client=self.client)
        self.configurables.append(self.history_manager)

    def get_source_and_reset(self):
        """
        Get the source code entered so far, and reset source input line(s).
        """
        source, self._source_lines_buffered = self._source_lines_buffered, []
        return "\n".join(source)

    def handle_source(self, line):
        """
        Save the line with previous source lines, and see if more
        input is needed. Returns more? and indent_string.
        """
        self._source_lines_buffered.append(line)
        ## Ask client if line is complete; get indent for next line:
        if self.use_kernel_is_complete:
            msg_id = self.client.is_complete("\n".join(self._source_lines_buffered))
            return self.handle_is_complete_reply(msg_id, timeout=self.kernel_is_complete_timeout)
        else:
            more = (line != "")
            return more, ""
