# Zulip trac plugin -- sends zulips when tickets change.
#
# Install by copying this file and zulip_trac_config.py to the trac
# plugins/ subdirectory, customizing the constants in
# zulip_trac_config.py, and then adding "zulip_trac" to the
# components section of the conf/trac.ini file, like so:
#
# [components]
# zulip_trac = enabled
#
# You may then need to restart trac (or restart Apache) for the bot
# (or changes to the bot) to actually be loaded by trac.

from trac.core import Component, implements
from trac.ticket import ITicketChangeListener
import sys
import os.path
sys.path.insert(0, os.path.dirname(__file__))
import zulip_trac_config as config
VERSION = "0.9"

from typing import Any, Dict

if config.ZULIP_API_PATH is not None:
    sys.path.append(config.ZULIP_API_PATH)

import zulip
client = zulip.Client(
    email=config.ZULIP_USER,
    site=config.ZULIP_SITE,
    api_key=config.ZULIP_API_KEY,
    client="ZulipTrac/" + VERSION)

def markdown_ticket_url(ticket, heading="ticket"):
    # type: (Any, str) -> str
    return "[%s #%s](%s/%s)" % (heading, ticket.id, config.TRAC_BASE_TICKET_URL, ticket.id)

def markdown_block(desc):
    # type: (str) -> str
    return "\n\n>" + "\n> ".join(desc.split("\n")) + "\n"

def truncate(string, length):
    # type: (str, int) -> str
    if len(string) <= length:
        return string
    return string[:length - 3] + "..."

def trac_subject(ticket):
    # type: (Any) -> str
    return truncate("#%s: %s" % (ticket.id, ticket.values.get("summary")), 60)

def send_update(ticket, content):
    # type: (Any, str) -> None
    client.send_message({
        "type": "stream",
        "to": config.STREAM_FOR_NOTIFICATIONS,
        "content": content,
        "subject": trac_subject(ticket)
    })

class ZulipPlugin(Component):
    implements(ITicketChangeListener)

    def ticket_created(self, ticket):
        # type: (Any) -> None
        """Called when a ticket is created."""
        content = "%s created %s in component **%s**, priority **%s**:\n" % \
            (ticket.values.get("reporter"), markdown_ticket_url(ticket),
             ticket.values.get("component"), ticket.values.get("priority"))
        # Include the full subject if it will be truncated
        if len(ticket.values.get("summary")) > 60:
            content += "**%s**\n" % (ticket.values.get("summary"),)
        if ticket.values.get("description") != "":
            content += "%s" % (markdown_block(ticket.values.get("description")),)
        send_update(ticket, content)

    def ticket_changed(self, ticket, comment, author, old_values):
        # type: (Any, str, str, Dict[str, Any]) -> None
        """Called when a ticket is modified.

        `old_values` is a dictionary containing the previous values of the
        fields that have changed.
        """
        if not (set(old_values.keys()).intersection(set(config.TRAC_NOTIFY_FIELDS)) or
                (comment and "comment" in set(config.TRAC_NOTIFY_FIELDS))):
            return

        content = "%s updated %s" % (author, markdown_ticket_url(ticket))
        if comment:
            content += ' with comment: %s\n\n' % (markdown_block(comment),)
        else:
            content += ":\n\n"
        field_changes = []
        for key, value in old_values.items():
            if key == "description":
                content += '- Changed %s from %s\n\nto %s' % (key, markdown_block(value),
                                                              markdown_block(ticket.values.get(key)))
            elif old_values.get(key) == "":
                field_changes.append('%s: => **%s**' % (key, ticket.values.get(key)))
            elif ticket.values.get(key) == "":
                field_changes.append('%s: **%s** => ""' % (key, old_values.get(key)))
            else:
                field_changes.append('%s: **%s** => **%s**' % (key, old_values.get(key),
                                                               ticket.values.get(key)))
        content += ", ".join(field_changes)

        send_update(ticket, content)

    def ticket_deleted(self, ticket):
        # type: (Any) -> None
        """Called when a ticket is deleted."""
        content = "%s was deleted." % markdown_ticket_url(ticket, heading="Ticket")
        send_update(ticket, content)