# vi: ts=4 expandtab
#
#    Copyright (C) 2009-2010 Canonical Ltd.
#    Copyright (C) 2012 Hewlett-Packard Development Company, L.P.
#
#    Author: Scott Moser <scott.moser@canonical.com>
#    Author: Juerg Hafliger <juerg.haefliger@hp.com>
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License version 3, as
#    published by the Free Software Foundation.
#
#    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, see <http://www.gnu.org/licenses/>.

import cloudinit.DataSource as DataSource

from cloudinit import seeddir as base_seeddir
from cloudinit import log
import cloudinit.util as util
import socket
import time
import boto.utils as boto_utils
import os.path


class DataSourceEc2(DataSource.DataSource):
    api_ver = '2009-04-04'
    seeddir = base_seeddir + '/ec2'
    metadata_address = "http://169.254.169.254"

    def __str__(self):
        return("DataSourceEc2")

    def get_data(self):
        seedret = {}
        if util.read_optional_seed(seedret, base=self.seeddir + "/"):
            self.userdata_raw = seedret['user-data']
            self.metadata = seedret['meta-data']
            log.debug("using seeded ec2 data in %s" % self.seeddir)
            return True

        try:
            if not self.wait_for_metadata_service():
                return False
            start = time.time()
            self.userdata_raw = boto_utils.get_instance_userdata(self.api_ver,
                None, self.metadata_address)
            self.metadata = boto_utils.get_instance_metadata(self.api_ver,
                self.metadata_address)
            log.debug("crawl of metadata service took %ds" % (time.time() -
                                                              start))
            return True
        except Exception as e:
            print e
            return False

    def get_instance_id(self):
        return(self.metadata['instance-id'])

    def get_availability_zone(self):
        return(self.metadata['placement']['availability-zone'])

    def get_local_mirror(self):
        return(self.get_mirror_from_availability_zone())

    def get_mirror_from_availability_zone(self, availability_zone=None):
        # availability is like 'us-west-1b' or 'eu-west-1a'
        if availability_zone == None:
            availability_zone = self.get_availability_zone()

        fallback = None

        if self.is_vpc():
            return fallback

        try:
            host = "%s.ec2.archive.ubuntu.com" % availability_zone[:-1]
            socket.getaddrinfo(host, None, 0, socket.SOCK_STREAM)
            return 'http://%s/ubuntu/' % host
        except:
            return fallback

    def wait_for_metadata_service(self):
        mcfg = self.ds_cfg

        if not hasattr(mcfg, "get"):
            mcfg = {}

        max_wait = 120
        try:
            max_wait = int(mcfg.get("max_wait", max_wait))
        except Exception:
            util.logexc(log)
            log.warn("Failed to get max wait. using %s" % max_wait)

        if max_wait == 0:
            return False

        timeout = 50
        try:
            timeout = int(mcfg.get("timeout", timeout))
        except Exception:
            util.logexc(log)
            log.warn("Failed to get timeout, using %s" % timeout)

        def_mdurls = ["http://169.254.169.254", "http://instance-data:8773"]
        mdurls = mcfg.get("metadata_urls", def_mdurls)

        # Remove addresses from the list that wont resolve.
        filtered = [x for x in mdurls if util.is_resolvable_url(x)]

        if set(filtered) != set(mdurls):
            log.debug("removed the following from metadata urls: %s" %
                list((set(mdurls) - set(filtered))))

        if len(filtered):
            mdurls = filtered
        else:
            log.warn("Empty metadata url list! using default list")
            mdurls = def_mdurls

        urls = []
        url2base = {False: False}
        for url in mdurls:
            cur = "%s/%s/meta-data/instance-id" % (url, self.api_ver)
            urls.append(cur)
            url2base[cur] = url

        starttime = time.time()
        url = util.wait_for_url(urls=urls, max_wait=max_wait,
                                timeout=timeout, status_cb=log.warn)

        if url:
            log.debug("Using metadata source: '%s'" % url2base[url])
        else:
            log.critical("giving up on md after %i seconds\n" %
                         int(time.time() - starttime))

        self.metadata_address = url2base[url]
        return (bool(url))

    def device_name_to_device(self, name):
        # consult metadata service, that has
        #  ephemeral0: sdb
        # and return 'sdb' for input 'ephemeral0'
        if 'block-device-mapping' not in self.metadata:
            return(None)

        found = None
        for entname, device in self.metadata['block-device-mapping'].items():
            if entname == name:
                found = device
                break
            # LP: #513842 mapping in Euca has 'ephemeral' not 'ephemeral0'
            if entname == "ephemeral" and name == "ephemeral0":
                found = device
        if found == None:
            log.debug("unable to convert %s to a device" % name)
            return None

        # LP: #611137
        # the metadata service may believe that devices are named 'sda'
        # when the kernel named them 'vda' or 'xvda'
        # we want to return the correct value for what will actually
        # exist in this instance
        mappings = {"sd": ("vd", "xvd")}
        ofound = found
        short = os.path.basename(found)

        if not found.startswith("/"):
            found = "/dev/%s" % found

        if os.path.exists(found):
            return(found)

        for nfrom, tlist in mappings.items():
            if not short.startswith(nfrom):
                continue
            for nto in tlist:
                cand = "/dev/%s%s" % (nto, short[len(nfrom):])
                if os.path.exists(cand):
                    log.debug("remapped device name %s => %s" % (found, cand))
                    return(cand)

        # on t1.micro, ephemeral0 will appear in block-device-mapping from
        # metadata, but it will not exist on disk (and never will)
        # at this pint, we've verified that the path did not exist
        # in the special case of 'ephemeral0' return None to avoid bogus
        # fstab entry (LP: #744019)
        if name == "ephemeral0":
            return None
        return ofound

    def is_vpc(self):
        # per comment in LP: #615545
        ph = "public-hostname"
        p4 = "public-ipv4"
        if ((ph not in self.metadata or self.metadata[ph] == "") and
            (p4 not in self.metadata or self.metadata[p4] == "")):
            return True
        return False


datasources = [
  (DataSourceEc2, (DataSource.DEP_FILESYSTEM, DataSource.DEP_NETWORK)),
]


# return a list of data sources that match this set of dependencies
def get_datasource_list(depends):
    return(DataSource.list_from_depends(depends, datasources))