###
# Copyright (c) 2020, Valentin Lorentz
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
#   * Redistributions of source code must retain the above copyright notice,
#     this list of conditions, and the following disclaimer.
#   * Redistributions in binary form must reproduce the above copyright notice,
#     this list of conditions, and the following disclaimer in the
#     documentation and/or other materials provided with the distribution.
#   * Neither the name of the author of this software nor the name of
#     contributors to this software may be used to endorse or promote products
#     derived from this software without specific prior written consent.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.

###

from supybot import conf, utils, plugins, ircutils, ircmsgs, callbacks
from supybot.commands import *

try:
    from supybot.i18n import PluginInternationalization

    _ = PluginInternationalization("Autocomplete")
except ImportError:
    # Placeholder that allows to run the plugin on a bot
    # without the i18n module
    _ = lambda x: x


REQUEST_TAG = "+draft/autocomplete-request"
RESPONSE_TAG = "+draft/autocomplete-response"


def _getAutocompleteResponse(irc, msg, payload):
    """Returns the value of the +draft/autocomplete-response tag for the given
    +draft/autocomplete-request payload."""
    tokens = callbacks.tokenize(payload, channel=msg.channel, network=irc.network)
    normalized_payload = " ".join(tokens)

    candidates = _getCandidates(irc, normalized_payload)

    if not candidates:
        return ""

    # strip what the user already typed
    assert all(candidate.startswith(normalized_payload) for candidate in candidates)
    normalized_payload_length = len(normalized_payload)
    candidate_commands = [
        candidate[normalized_payload_length:] for candidate in candidates
    ]

    tokenized_candidates = [
        callbacks.tokenize(c, channel=msg.channel, network=irc.network)
        for c in candidate_commands
    ]

    response_items = {candidate[0] for candidate in tokenized_candidates}

    return "\t".join(sorted(response_items))


def _getCandidates(irc, normalized_payload):
    """Returns a list of commands starting with the normalized_payload."""
    candidates = set()
    for cb in irc.callbacks:
        cb_commands = cb.listCommands()

        # copy them with the plugin name (optional when calling a command)
        # at the beginning
        plugin_name = cb.canonicalName()
        cb_commands += [plugin_name + " " + command for command in cb_commands]

        candidates |= {
            command for command in cb_commands if command.startswith(normalized_payload)
        }

    return candidates


class Autocomplete(callbacks.Plugin):
    """Provides command completion for IRC clients that support it."""

    def _enabled(self, irc, msg):
        return conf.supybot.protocols.irc.experimentalExtensions() and self.registryValue(
            "enabled", msg.channel, irc.network
        )

    def doTagmsg(self, irc, msg):
        if REQUEST_TAG not in msg.server_tags:
            return
        if not "msgid" in msg.server_tags:
            return
        if not self._enabled(irc, msg):
            return

        msgid = msg.server_tags["msgid"]

        text = msg.server_tags[REQUEST_TAG]

        # using callbacks._addressed instead of callbacks.addressed, as
        # callbacks.addressed would tag the m
        payload = callbacks._addressed(irc, msg, payload=text)

        if not payload:
            # not addressed
            return

        # marks used by '_addressed' are usually prefixes (char, string,
        # nick), but may also be suffixes (with
        # supybot.reply.whenAddressedBy.nick.atEnd); but there is no way to
        # have it in the middle of the message AFAIK.
        assert payload in text

        if not text.endswith(payload):
            # If there is a suffix, it means the end of the text is used to
            # address the bot, so it can't be a method to be completed.
            return

        autocomplete_response = _getAutocompleteResponse(irc, msg, payload)
        if not autocomplete_response:
            return

        target = msg.channel or ircutils.nickFromHostmask(msg.prefix)
        irc.queueMsg(
            ircmsgs.IrcMsg(
                server_tags={
                    "+draft/reply": msgid,
                    RESPONSE_TAG: autocomplete_response,
                },
                command="TAGMSG",
                args=[target],
            )
        )


Class = Autocomplete


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