#!/usr/bin/python3

from lxml import etree as ET
import cmdln
import datetime
import logging
import signal
import sys
import time

from urllib.error import HTTPError, URLError

import osc.conf
import osc.core

from osclib.memoize import memoize

logger = logging.getLogger()

http_GET = osc.core.http_GET
http_DELETE = osc.core.http_DELETE
http_POST = osc.core.http_POST


def chunks(line, n):
    """ Yield successive n-sized chunks from l.
    """
    # http://stackoverflow.com/questions/312443/how-do-you-split-a-list-into-evenly-sized-chunks-in-python
    for i in range(0, len(line), n):
        yield line[i:i + n]


class ToolBase(object):
    def __init__(self):
        self.apiurl = osc.conf.config['apiurl']
        self.debug = osc.conf.config['debug']
        self.caching = False
        self.dryrun = False

    @memoize(add_invalidate=True)
    def _cached_GET(self, url):
        return self.retried_GET(url).read()

    def cached_GET(self, url):
        if self.caching:
            return self._cached_GET(url)
        return self.retried_GET(url).read()

    def retried_GET(self, url):
        try:
            return http_GET(url)
        except HTTPError as e:
            if 500 <= e.code <= 599:
                print('Retrying {}'.format(url))
                time.sleep(1)
                return self.retried_GET(url)
            logging.error('%s: %s', e, url)
            raise e
        except URLError as e:
            logging.error('%s: "%s - %s" %s', e, e.reason, type(e.reason), url)
            # connection timeout
            if isinstance(e.reason, TimeoutError):
                print('Retrying {}'.format(url))
                time.sleep(1)
                return self.retried_GET(url)
            raise e

    def http_PUT(self, *args, **kwargs):
        if self.dryrun:
            logging.debug("dryrun PUT %s %s", args, str(kwargs)[:200])
        else:
            osc.core.http_PUT(*args, **kwargs)

    def http_POST(self, *args, **kwargs):
        if self.dryrun:
            logging.debug("dryrun POST %s %s", args, str(kwargs)[:200])
        else:
            osc.core.http_POST(*args, **kwargs)

    def get_project_meta(self, prj):
        url = self.makeurl(['source', prj, '_meta'])
        return self.cached_GET(url)

    def _meta_get_packagelist(self, prj, deleted=None, expand=False):

        query = {}
        if deleted:
            query['deleted'] = 1
        if expand:
            query['expand'] = 1

        u = self.makeurl(['source', prj], query)
        return self.cached_GET(u)

    def meta_get_packagelist(self, prj, deleted=None, expand=False):
        root = ET.fromstring(self._meta_get_packagelist(prj, deleted, expand))
        res = list()
        for node in root.findall('entry'):
            name = node.get('name')
            if not (name == '000product' or name.startswith('patchinfo.')):
                res.push(name)
        return res

    def latest_packages(self, project):
        data = self.cached_GET(self.makeurl(['project', 'latest_commits', project]))
        lc = ET.fromstring(data)
        packages = set()
        for entry in lc.findall('{http://www.w3.org/2005/Atom}entry'):
            title = entry.find('{http://www.w3.org/2005/Atom}title').text
            if title.startswith('In '):
                packages.add(title[3:].split(' ')[0])
        return sorted(packages)

    def makeurl(self, paths, query=None):
        """
        Wrapper around osc's makeurl passing our apiurl
        :return url made for l and query
        """
        query = [] if not query else query
        return osc.core.makeurl(self.apiurl, paths, query)

    def process(self, packages):
        """ reimplement this """
        True


class CommandLineInterface(cmdln.Cmdln):
    def __init__(self, *args, **kwargs):
        cmdln.Cmdln.__init__(self, *args, **kwargs)

    def get_optparser(self):
        parser = cmdln.Cmdln.get_optparser(self)
        parser.add_option("--apiurl", '-A', metavar="URL", help="api url")
        parser.add_option("--dry", action="store_true", help="dry run")
        parser.add_option("-d", "--debug", action="store_true", help="debug output")
        parser.add_option("--osc-debug", action="store_true", help="osc debug output")
        parser.add_option("--verbose", action="store_true", help="verbose")
        parser.add_option("--http-debug", action="store_true", help="osc http debug output")
        parser.add_option('--http-full-debug', action='store_true',
                          help='debug HTTP traffic (filters no headers)')
        parser.add_option('--cache-requests', action='store_true', default=False,
                          help='cache GET requests. Not recommended for daily use.')

        return parser

    def postoptparse(self):
        level = None
        if (self.options.debug):
            level = logging.DEBUG
        elif (self.options.verbose):
            level = logging.INFO

        logging.basicConfig(level=level)

        osc.conf.get_config(override_apiurl=self.options.apiurl,
                            override_debug=self.options.osc_debug,
                            override_http_debug=self.options.http_debug,
                            override_http_full_debug=self.options.http_full_debug)

        self.tool = self.setup_tool()
        self.tool.dryrun = self.options.dry
        self.tool.caching = self.options.cache_requests

    def setup_tool(self, toolclass=ToolBase):
        """ reimplement this """

        tool = toolclass()

        return tool

# example
#    @cmdln.option('-n', '--interval', metavar="minutes", type="int", help="periodic interval in minutes")
#    def do_process(self, subcmd, opts, project):
#        def work():
#            self.tool.process()
#
#        self.runner(work, opts.interval)

    def runner(self, workfunc, interval):
        """ runs the specified callback every <interval> minutes or
        once if interval is None or 0
        """
        class ExTimeout(Exception):
            """raised on timeout"""

        if interval:
            def alarm_called(nr, frame):
                raise ExTimeout()
            signal.signal(signal.SIGALRM, alarm_called)

        while True:
            try:
                workfunc()
            except Exception as e:
                logger.exception(e)

            if interval:
                logger.info("sleeping %d minutes. Press enter to check now ..." % interval)
                signal.alarm(interval * 60)
                try:
                    input()
                except ExTimeout:
                    pass
                signal.alarm(0)
                logger.info("recheck at %s" % datetime.datetime.now().isoformat())
                continue
            break


if __name__ == "__main__":
    app = CommandLineInterface()
    sys.exit(app.main())