# This file is part of Buildbot.  Buildbot is free software: you can
# redistribute it and/or modify it under the terms of the GNU General Public
# License as published by the Free Software Foundation, version 2.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc., 51
# Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
# Portions Copyright Buildbot Team Members
# Portions Copyright 2011 National Instruments


# Many thanks to Dave Peticolas for contributing this module

import re
import time
import os

from twisted.python import log
from twisted.internet import defer, utils

from buildbot import util
from buildbot.changes import base

class P4PollerError(Exception):
    """Something went wrong with the poll. This is used as a distinctive
    exception type so that unit tests can detect and ignore it."""

def get_simple_split(branchfile):
    """Splits the branchfile argument and assuming branch is 
       the first path component in branchfile, will return
       branch and file else None."""

    index = branchfile.find('/')
    if index == -1: return None, None
    branch, file = branchfile.split('/', 1)
    return branch, file

class P4Source(base.PollingChangeSource, util.ComparableMixin):
    """This source will poll a perforce repository for changes and submit
    them to the change master."""

    compare_attrs = ["p4port", "p4user", "p4passwd", "p4base",
                     "p4bin", "pollInterval"]

    env_vars = ["P4CLIENT", "P4PORT", "P4PASSWD", "P4USER",
                "P4CHARSET"]

    changes_line_re = re.compile(
            r"Change (?P<num>\d+) on \S+ by \S+@\S+ '.*'$")
    describe_header_re = re.compile(
            r"Change \d+ by (?P<who>\S+)@\S+ on (?P<when>.+)$")
    file_re = re.compile(r"^\.\.\. (?P<path>[^#]+)#\d+ [/\w]+$")
    datefmt = '%Y/%m/%d %H:%M:%S'

    parent = None # filled in when we're added
    last_change = None
    loop = None

    def __init__(self, p4port=None, p4user=None, p4passwd=None,
                 p4base='//', p4bin='p4',
                 split_file=lambda branchfile: (None, branchfile),
                 pollInterval=60 * 10, histmax=None, pollinterval=-2,
                 encoding='utf8', project=None, name=None):

        # for backward compatibility; the parameter used to be spelled with 'i'
        if pollinterval != -2:
            pollInterval = pollinterval

        base.PollingChangeSource.__init__(self, name=name, pollInterval=pollInterval)

        if project is None:
            project = ''

        self.p4port = p4port
        self.p4user = p4user
        self.p4passwd = p4passwd
        self.p4base = p4base
        self.p4bin = p4bin
        self.split_file = split_file
        self.encoding = encoding
        self.project = project

    def describe(self):
        return "p4source %s %s" % (self.p4port, self.p4base)

    def poll(self):
        d = self._poll()
        d.addErrback(log.err, 'P4 poll failed')
        return d

    def _get_process_output(self, args):
        env = dict([(e, os.environ.get(e)) for e in self.env_vars if os.environ.get(e)])
        d = utils.getProcessOutput(self.p4bin, args, env)
        return d

    @defer.inlineCallbacks
    def _poll(self):
        args = []
        if self.p4port:
            args.extend(['-p', self.p4port])
        if self.p4user:
            args.extend(['-u', self.p4user])
        if self.p4passwd:
            args.extend(['-P', self.p4passwd])
        args.extend(['changes'])
        if self.last_change is not None:
            args.extend(['%s...@%d,now' % (self.p4base, self.last_change+1)])
        else:
            args.extend(['-m', '1', '%s...' % (self.p4base,)])

        result = yield self._get_process_output(args)

        last_change = self.last_change
        changelists = []
        for line in result.split('\n'):
            line = line.strip()
            if not line: continue
            m = self.changes_line_re.match(line)
            if not m:
                raise P4PollerError("Unexpected 'p4 changes' output: %r" % result)
            num = int(m.group('num'))
            if last_change is None:
                # first time through, the poller just gets a "baseline" for where to
                # start on the next poll
                log.msg('P4Poller: starting at change %d' % num)
                self.last_change = num
                return
            changelists.append(num)
        changelists.reverse() # oldest first

        # Retrieve each sequentially.
        for num in changelists:
            args = []
            if self.p4port:
                args.extend(['-p', self.p4port])
            if self.p4user:
                args.extend(['-u', self.p4user])
            if self.p4passwd:
                args.extend(['-P', self.p4passwd])
            args.extend(['describe', '-s', str(num)])
            result = yield self._get_process_output(args)

            # decode the result from its designated encoding
            result = result.decode(self.encoding)

            lines = result.split('\n')
            # SF#1555985: Wade Brainerd reports a stray ^M at the end of the date
            # field. The rstrip() is intended to remove that.
            lines[0] = lines[0].rstrip()
            m = self.describe_header_re.match(lines[0])
            if not m:
                raise P4PollerError("Unexpected 'p4 describe -s' result: %r" % result)
            who = m.group('who')
            when = time.mktime(time.strptime(m.group('when'), self.datefmt))
            comments = ''
            while not lines[0].startswith('Affected files'):
                comments += lines.pop(0) + '\n'
            lines.pop(0) # affected files

            branch_files = {} # dict for branch mapped to file(s)
            while lines:
                line = lines.pop(0).strip()
                if not line: continue
                m = self.file_re.match(line)
                if not m:
                    raise P4PollerError("Invalid file line: %r" % line)
                path = m.group('path')
                if path.startswith(self.p4base):
                    branch, file = self.split_file(path[len(self.p4base):])
                    if (branch == None and file == None): continue
                    if branch_files.has_key(branch):
                        branch_files[branch].append(file)
                    else:
                        branch_files[branch] = [file]

            for branch in branch_files:
                yield self.master.addChange(
                       author=who,
                       files=branch_files[branch],
                       comments=comments,
                       revision=str(num),
                       when_timestamp=util.epoch2datetime(when),
                       branch=branch,
                       project=self.project)

            self.last_change = num
