#!/usr/bin/env python

import socket
import time
import os
import base64
from subprocess import check_call

from trac.core import *
from trac import util
from trac.ticket.query import Query
from trac.ticket.model import Ticket
from trac.env import IEnvironmentSetupParticipant
from trac.perm import IPermissionRequestor
from trac.web.main import IRequestHandler
from trac.web.chrome import INavigationContributor, ITemplateProvider, add_warning

from action_logic import is_branchable, is_rebranchable, is_mergeable, is_checkmergeable

class MergeBotModule(Component):
    implements(INavigationContributor, IPermissionRequestor, IRequestHandler, ITemplateProvider, IEnvironmentSetupParticipant)

    # IEnvironmentSetupParticipant
    def environment_created(self):
        self._setup_config()

    def environment_needs_upgrade(self, db):
        return not list(self.config.options('mergebot'))

    def upgrade_environment(self, db):
        self._setup_config()

    def _setup_config(self):
        self.config.set('mergebot', 'work_dir', 'mergebot')
        self.config.set('mergebot', 'repository_url', 'http://FIXME/svn')
        self.config.set('mergebot', 'listen.ip', 'localhost')
        self.config.set('mergebot', 'listen.port', '12345')
        self.config.set('mergebot', 'worker_count', '2')
        # Set up the needed custom field for the bot
        self.config.set('ticket-custom', 'mergebotstate', 'select')
        self.config.set('ticket-custom', 'mergebotstate.label', 'MergeBotState')
        self.config.set('ticket-custom', 'mergebotstate.options', '| merged | branched | conflicts')
        self.config.set('ticket-custom', 'mergebotstate.value', '')
        self.config.save()

    # INavigationContributor
    # so it shows up in the main nav bar
    def get_active_navigation_item(self, req):
        return 'mergebot'

    def get_navigation_items(self, req):
        """Generator that yields the MergeBot tab, but only if the user has
        MERGEBOT_VIEW privs."""
        if req.perm.has_permission("MERGEBOT_VIEW"):
            label = util.Markup('<a href="%s">MergeBot</a>' % \
                req.href.mergebot())
            yield ('mainnav', 'mergebot', label)

    # IPermissionRequestor methods
    # So we can control access to this functionality
    def get_permission_actions(self):
        """Returns a permission structure."""
        actions = ["MERGEBOT_VIEW", "MERGEBOT_BRANCH", "MERGEBOT_MERGE_TICKET",
            "MERGEBOT_MERGE_RELEASE"]
        # MERGEBOT_ADMIN implies all of the above permissions
        allactions = actions + [
            ("MERGEBOT_ADMIN", actions),
            ("MERGEBOT_BRANCH", ["MERGEBOT_VIEW"]),
            ("MERGEBOT_MERGE_TICKET", ["MERGEBOT_VIEW"]),
            ("MERGEBOT_MERGE_RELEASE", ["MERGEBOT_VIEW"])
            ]
        return allactions

    # IRequestHandler
    def match_request(self, req):
        """Returns true, if the given request path is handled by this module"""
        # For now, we don't recognize any arguments...
        return req.path_info == "/mergebot" or req.path_info.startswith("/mergebot/")

    def _get_ticket_info(self, ticketid):
        # grab the ticket info we care about
        fields = ['summary', 'component', 'version', 'status']
        info = {}
        if ticketid:
            ticket = Ticket(self.env, ticketid)
            for field in fields:
                info[field] = ticket[field]
            info['href'] = self.env.href.ticket(ticketid)
            self.log.debug("id=%s, info=%r" % (ticketid, info))
        return info

    def daemon_address(self):
        host = self.env.config.get('mergebot', 'listen.ip')
        port = int(self.env.config.get('mergebot', 'listen.port'))
        return (host, port)

    def start_daemon(self):
        check_call(['mergebotdaemon', self.env.path])
        time.sleep(1) # bleh

    def _daemon_cmd(self, cmd):
        self.log.debug('Sending mergebotdaemon: %r' % cmd)
        try:
            info_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            info_socket.connect(self.daemon_address())
        except socket.error, e:
            # if we're refused, try starting the daemon and re-try
            if e and e[0] == 111:
                self.log.debug('connection to mergebotdaemon refused, trying to start mergebotdaemon')
                self.start_daemon()
            self.log.debug('Resending mergebotdaemon: %r' % cmd)
            info_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            info_socket.connect(self.daemon_address())
        info_socket.sendall(cmd)
        self.log.debug('Reading mergebotdaemon response')
        raw = info_socket.recv(4096)
        info_socket.close()
        self.log.debug('Reading mergebotdaemon response was %r' % raw)
        return raw

    def process_request(self, req):
        """This is the function called when a user requests a mergebot page."""
        req.perm.assert_permission("MERGEBOT_VIEW")

        # 2nd redirect back to the real mergebot page to address POST and
        # browser refresh
        if req.path_info == "/mergebot/redir":
            req.redirect(req.href.mergebot())

        data = {}

        if req.method == "POST": # The user hit a button
            if req.args['action'] in ['Branch', 'Rebranch', 'CheckMerge', 'Merge']:
                ticketnum = req.args['ticket']
                component = req.args['component']
                version = req.args['version']
                requestor = req.authname or 'anonymous'
                ticket = Ticket(self.env, int(ticketnum))
                # FIXME: check for 'todo' key?
                # If the request is not valid, just ignore it.
                action = None
                if req.args['action'] == "Branch":
                    req.perm.assert_permission("MERGEBOT_BRANCH")
                    if is_branchable(ticket):
                        action = 'branch'
                elif req.args['action'] == "Rebranch":
                    req.perm.assert_permission("MERGEBOT_BRANCH")
                    if is_rebranchable(ticket):
                        action = 'rebranch'
                elif req.args['action'] == "CheckMerge":
                    req.perm.assert_permission("MERGEBOT_VIEW")
                    if is_checkmergeable(ticket):
                        action = 'checkmerge'
                elif req.args['action'] == "Merge":
                    if version.startswith("#"):
                        req.perm.assert_permission("MERGEBOT_MERGE_TICKET")
                    else:
                        req.perm.assert_permission("MERGEBOT_MERGE_RELEASE")
                    if is_mergeable(ticket):
                        action = 'merge'
                if action:
                    command = 'ADD %s %s %s %s %s\nQUIT\n' % (ticketnum, action, component, version, requestor)
                    result = self._daemon_cmd(command)
                    if 'OK' not in result:
                        add_warning(req, result)
            if req.args['action'] == "Cancel":
                command = 'CANCEL %s\nQUIT\n' % req.args['task']
                result = self._daemon_cmd(command)
                if 'OK' not in result:
                    add_warning(req, result)
            # First half of a double-redirect to make a refresh not re-send the
            # POST data.
            req.redirect(req.href.mergebot("redir"))

        # We want to fill out the information for the page unconditionally.

        # Connect to the daemon and read the current queue information
        raw_queue_info = self._daemon_cmd('LIST\nQUIT\n')
        # Parse the queue information into something we can display
        queue_info = [x.split(',') for x in raw_queue_info.split('\n') if ',' in x]
        status_map = {
            'Z':'Zombie',
            'R':'Running',
            'Q':'Queued',
            'W':'Waiting',
            'P':'Pending',
        }
        for row in queue_info:
            status = row[1]
            row[1] = status_map[status]
            summary = row[7]
            row[7] = base64.b64decode(summary)

        data['queue'] = queue_info

        queued_tickets = set([int(q[2]) for q in queue_info])

        # Provide the list of tickets at the bottom of the page, along with
        # flags for which buttons should be enabled for each ticket.
        # I need to get a list of tickets.  For non-admins, restrict the list
        # to the tickets owned by that user.
        querystring = "status!=closed&version!="
        required_columns = ["component", "version", "mergebotstate"]
        if req.perm.has_permission("MERGEBOT_ADMIN"):
            required_columns.append("owner")
        else:
            querystring += "&owner=%s" % (req.authname,)
        query = Query.from_string(self.env, querystring, order="id")
        columns = query.get_columns()
        for name in required_columns:
            if name not in columns:
                columns.append(name)
        db = self.env.get_db_cnx()
        tickets = query.execute(req, db)
        data['unqueued'] = []
        for ticket in tickets:
            ticketnum = ticket['id']
            if ticketnum in queued_tickets:
                # Don't allow more actions to be taken on a ticket that is
                # currently queued for something.  In the future, we may want
                # to support a 'Cancel' button, though.  Or present actions
                # based upon the expected state of the ticket
                continue

            ticket_info = {'info': ticket}
            data['unqueued'].append(ticket_info)

            # Select what actions this user may make on this ticket based on
            # its current state.

            # MERGE
            ticket_info['merge'] = False
            if ticket['version'].startswith('#'):
                if req.perm.has_permission("MERGEBOT_MERGE_TICKET"):
                    ticket_info['merge'] = is_mergeable(ticket)
            else:
                if req.perm.has_permission("MERGEBOT_MERGE_RELEASE"):
                    ticket_info['merge'] = is_mergeable(ticket)
            # CHECK-MERGE
            if req.perm.has_permission("MERGEBOT_VIEW"):
                ticket_info['checkmerge'] = is_checkmergeable(ticket)
            else:
                ticket_info['checkmerge'] = False
            # BRANCH, REBRANCH
            if req.perm.has_permission("MERGEBOT_BRANCH"):
                ticket_info['branch'] = is_branchable(ticket)
                ticket_info['rebranch'] = is_rebranchable(ticket)
            else:
                ticket_info['branch'] = False
                ticket_info['rebranch'] = False

        # proactive warnings
        work_dir = self.env.config.get('mergebot', 'work_dir')
        if not os.path.isabs(work_dir):
            work_dir = os.path.join(self.env.path, work_dir)
        if not os.path.isdir(work_dir):
            add_warning(req, 'The Mergebot work directory "%s" does not exist.' % work_dir)

        return "mergebot.html", data, None

    # ITemplateProvider
    def get_htdocs_dirs(self):
        return []

    def get_templates_dirs(self):
        # It appears that everyone does this import here instead of at the top
        # level... I'm not sure I understand why...
        from pkg_resources import resource_filename
        return [resource_filename(__name__, 'templates')]

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