# vi: ts=4 expandtab
#
#    Copyright (C) 2012 Canonical Ltd.
#    Copyright (C) 2012 Hewlett-Packard Development Company, L.P.
#    Copyright (C) 2012 Yahoo! Inc.
#
#    Author: Scott Moser <scott.moser@canonical.com>
#    Author: Juerg Haefliger <juerg.haefliger@hp.com>
#    Author: Joshua Harlow <harlowja@yahoo-inc.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 cPickle as pickle

import copy
import os
import sys

try:
    from configobj import ConfigObj
except ImportError:
    ConfigObj = None

from cloudinit.settings import (OLD_CLOUD_CONFIG)
from cloudinit.settings import (PER_INSTANCE, FREQUENCIES)

from cloudinit.handlers import boot_hook as bh_part
from cloudinit.handlers import cloud_config as cc_part
from cloudinit.handlers import shell_script as ss_part
from cloudinit.handlers import upstart_job as up_part

from cloudinit import cloud
from cloudinit import distros
from cloudinit import helpers
from cloudinit import importer
from cloudinit import log as logging
from cloudinit import sources
from cloudinit import transforms
from cloudinit import user_data as ud
from cloudinit import util

LOG = logging.getLogger(__name__)


class Init(object):
    def __init__(self, ds_deps=None):
        if ds_deps:
            self.ds_deps = ds_deps
        else:
            self.ds_deps = [sources.DEP_FILESYSTEM, sources.DEP_NETWORK]
        # Created on first use
        self._cfg = None
        self._paths = None
        self._distro = None
        # Created only when a fetch occurs
        self.datasource = None

    def _read_cfg_old(self):
        # Support reading the old ConfigObj format file and merging
        # it into the yaml dictionary
        if not ConfigObj:
            return {}
        old_cfg = ConfigObj(OLD_CLOUD_CONFIG)
        return dict(old_cfg)

    @property
    def distro(self):
        if not self._distro:
            # Try to find the right class to use
            d_cfg = self._extract_cfg('system')
            distro_name = d_cfg.pop('distro', 'ubuntu')
            distro_cls = distros.fetch(distro_name)
            LOG.debug("Using distro class %s", distro_cls)
            distro = distro_cls(distro_name, d_cfg,
                                helpers.Runners(self.paths))
            self._distro = distro
        return self._distro

    @property
    def cfg(self):
        return self._extract_cfg('restricted')

    def _extract_cfg(self, restriction):
        # None check so that we don't keep on re-loading if empty
        if self._cfg is None:
            self._cfg = self._read_cfg()
            LOG.debug("Loading init config %s", self._cfg)
        # Nobody gets the real config
        ocfg = copy.deepcopy(self._cfg)
        if restriction == 'restricted':
            ocfg.pop('system_info', None)
        elif restriction == 'system':
            ocfg = util.get_cfg_by_path(ocfg, ('system_info',), {})
        elif restriction == 'paths':
            ocfg = util.get_cfg_by_path(ocfg, ('system_info', 'paths'), {})
        if not isinstance(ocfg, (dict)):
            ocfg = {}
        return ocfg

    @property
    def paths(self):
        if not self._paths:
            path_info = self._extract_cfg('paths')
            self._paths = helpers.Paths(path_info, self.datasource)
        return self._paths

    def _initial_subdirs(self):
        c_dir = self.paths.cloud_dir
        initial_dirs = [
            c_dir,
            os.path.join(c_dir, 'scripts'),
            os.path.join(c_dir, 'scripts', 'per-instance'),
            os.path.join(c_dir, 'scripts', 'per-once'),
            os.path.join(c_dir, 'scripts', 'per-boot'),
            os.path.join(c_dir, 'seed'),
            os.path.join(c_dir, 'instances'),
            os.path.join(c_dir, 'handlers'),
            os.path.join(c_dir, 'sem'),
            os.path.join(c_dir, 'data'),
        ]
        return initial_dirs

    def purge_cache(self, rmcur=True):
        rmlist = []
        rmlist.append(self.paths.boot_finished)
        if rmcur:
            rmlist.append(self.paths.instance_link)
        for f in rmlist:
            util.del_file(f)
        return len(rmlist)

    def initialize(self):
        self._initialize_filesystem()

    def _initialize_filesystem(self):
        util.ensure_dirs(self._initial_subdirs())
        log_file = util.get_cfg_option_str(self.cfg, 'def_log_file')
        perms = util.get_cfg_option_str(self.cfg, 'syslog_fix_perms')
        if log_file:
            util.ensure_file(log_file)
            if perms:
                (u, g) = perms.split(':', 1)
                if u == "-1" or u == "None":
                    u = None
                if g == "-1" or g == "None":
                    g = None
                util.chownbyname(log_file, u, g)

    def _read_cfg(self):
        b_config = util.get_builtin_cfg()
        try:
            conf = util.get_base_cfg()
        except Exception:
            conf = b_config
        return util.mergedict(conf, self._read_cfg_old())

    def _restore_from_cache(self):
        pickled_fn = self.paths.get_ipath_cur('obj_pkl')
        try:
            # we try to restore from a current link and static path
            # by using the instance link, if purge_cache was called
            # the file wont exist
            return pickle.loads(util.load_file(pickled_fn))
        except Exception:
            util.logexc(LOG, "Failed loading pickled datasource from %s",
                        pickled_fn)
            return None

    def _write_to_cache(self):
        pickled_fn = self.paths.get_ipath_cur("obj_pkl")
        try:
            contents = pickle.dumps(self.datasource)
            util.write_file(pickled_fn, contents, mode=0400)
        except Exception:
            util.logexc(LOG, "Failed pickling datasource to %s", pickled_fn)
            return False

    def _get_datasources(self):
        # Any config provided???
        pkg_list = self.cfg.get('datasource_pkg_list') or []
        # Add the defaults at the end
        for n in [util.obj_name(sources), '']:
            if n not in pkg_list:
                pkg_list.append(n)
        cfg_list = self.cfg.get('datasource_list') or []
        return (cfg_list, pkg_list)

    def _get_data_source(self):
        if self.datasource:
            return self.datasource
        ds = self._restore_from_cache()
        if ds:
            LOG.debug("Restored from cache datasource: %s" % ds)
        else:
            (cfg_list, pkg_list) = self._get_datasources()
            # Deep copy so that user-data handlers can not modify
            # (which will affect user-data handlers down the line...)
            sys_cfg = copy.deepcopy(self.cfg)
            ds_deps = copy.deepcopy(self.ds_deps)
            (ds, dsname) = sources.find_source(sys_cfg, self.distro,
                                               self.paths,
                                               ds_deps, cfg_list, pkg_list)
            LOG.debug("Loaded datasource %s - %s", dsname, ds)
        self.datasource = ds
        # Ensure we adjust our path members datasource
        # now that we have one (thus allowing ipath to be used)
        self.paths.datasource = ds
        return ds

    def _reflect_cur_instance(self):
        # Ensure we are hooked into the right symlink for the current instance
        idir = self.paths.get_ipath()
        util.del_file(self.paths.instance_link)
        util.sym_link(idir, self.paths.instance_link)

        # Ensures these dirs exist
        dir_list = []
        for d in ["handlers", "scripts", "sem"]:
            dir_list.append(os.path.join(idir, d))
        util.ensure_dirs(dir_list)

        # Write out information on what is being used for the current instance
        # and what may have been used for a previous instance...
        dp = self.paths.get_cpath('data')

        # Write what the datasource was and is..
        ds = "%s: %s" % (util.obj_name(self.datasource), self.datasource)
        previous_ds = ''
        ds_fn = os.path.join(idir, 'datasource')
        try:
            previous_ds = util.load_file(ds_fn).strip()
        except Exception:
            pass
        if not previous_ds:
            # TODO: ?? is this right
            previous_ds = ds
        util.write_file(ds_fn, "%s\n" % ds)
        util.write_file(os.path.join(dp, 'previous-datasource'),
                        "%s\n" % (previous_ds))

        # What the instance id was and is...
        iid = self.datasource.get_instance_id()
        previous_iid = ''
        p_iid_fn = os.path.join(dp, 'previous-instance-id')
        c_iid_fn = os.path.join(dp, 'instance-id')
        try:
            previous_iid = util.load_file(p_iid_fn).strip()
        except Exception:
            pass
        if not previous_iid:
            # TODO: ?? is this right
            previous_iid = iid
        util.write_file(c_iid_fn, "%s\n" % iid)
        util.write_file(p_iid_fn, "%s\n" % previous_iid)
        return iid

    def fetch(self):
        return self._get_data_source()

    def instancify(self):
        return self._reflect_cur_instance()

    def cloudify(self):
        # Form the needed options to cloudify our members
        return cloud.Cloud(self.datasource, 
                           self.paths, self.cfg,
                           self.distro, helpers.Runners(self.paths))

    def update(self):
        self._write_to_cache()
        self._store_userdata()

    def _store_userdata(self):
        raw_ud = "%s" % (self.datasource.get_userdata_raw())
        util.write_file(self.paths.get_ipath('userdata_raw'), raw_ud, 0600)
        processed_ud = "%s" % (self.datasource.get_userdata())
        util.write_file(self.paths.get_ipath('userdata'), processed_ud, 0600)

    def _default_userdata_handlers(self):
        opts = {
            'paths': self.paths,
            'instance_id': self.datasource.get_instance_id(),
        }
        # TODO Hmmm, should we dynamically import these??
        def_handlers = [
            cc_part.CloudConfigPartHandler(**opts),
            ss_part.ShellScriptPartHandler(**opts),
            bh_part.BootHookPartHandler(**opts),
            up_part.UpstartJobPartHandler(**opts),
        ]
        return def_handlers

    def consume(self, frequency=PER_INSTANCE):
        cdir = self.paths.get_cpath("handlers")
        idir = self.paths.get_ipath("handlers")
    
        # Add the path to the plugins dir to the top of our list for import
        # instance dir should be read before cloud-dir
        sys.path.insert(0, cdir)
        sys.path.insert(0, idir)

        # Ensure datasource fetched before activation (just incase)
        ud_obj = self.datasource.get_userdata()

        # This keeps track of all the active handlers
        c_handlers = helpers.ContentHandlers(paths=self.paths)

        # Add handlers in cdir
        potential_handlers = util.find_modules(cdir)
        for (fname, modname) in potential_handlers.iteritems():
            try:
                mod = ud.fixup_handler(importer.import_module(modname))
                types = c_handlers.register(mod)
                LOG.debug("Added handler for %s from %s", types, fname)
            except:
                util.logexc(LOG, "Failed to register handler from %s", fname)

        def_handlers = self._default_userdata_handlers()
        applied_def_handlers = c_handlers.register_defaults(def_handlers)
        if applied_def_handlers:
            LOG.debug("Registered default handlers: %s", applied_def_handlers)

        # Form our cloud interface
        data = self.cloudify()

        # Init the handlers first
        called = []
        for (_ctype, mod) in c_handlers.iteritems():
            if mod in called:
                continue
            ud.call_begin(mod, data, frequency)
            called.append(mod)

        # Walk the user data
        part_data = {
            'handlers': c_handlers,
            'handlerdir': idir,
            'data': data, 
            'frequency': frequency,
            # This will be used when new handlers are found
            # to help write there contents to files with numbered
            # names...
            'handlercount': 0,
        }
        ud.walk(ud_obj, ud.walker_callback, data=part_data)

        # Give callbacks opportunity to finalize
        called = []
        for (_ctype, mod) in c_handlers.iteritems():
            if mod in called:
                continue
            ud.call_end(mod, data, frequency)
            called.append(mod)


class Transforms(object):
    def __init__(self, init, cfgfile=None):
        self.datasource = init.fetch()
        self.cfgfile = cfgfile
        self.basecfg = copy.deepcopy(init.cfg)
        self.init = init
        # Created on first use
        self._cachedcfg = None

    @property
    def cfg(self):
        if self._cachedcfg is None:
            self._cachedcfg = self._get_config(self.cfgfile)
            LOG.debug("Loading module config %s", self._cachedcfg)
        return self._cachedcfg

    def _get_config(self, cfgfile):
        mcfg = None

        if self.cfgfile:
            try:
                mcfg = util.read_conf(cfgfile)
            except:
                util.logexc(LOG, ("Failed loading of cloud config '%s'. "
                                  "Continuing with an empty config."), cfgfile)
        if not mcfg:
            mcfg = {}

        ds_cfg = None
        try:
            ds_cfg = self.datasource.get_config_obj()
        except:
            util.logexc(LOG, "Failed loading of datasource config object.")
        if not ds_cfg:
            ds_cfg = {}

        mcfg = util.mergedict(mcfg, ds_cfg)
        if self.basecfg:
            return util.mergedict(mcfg, self.basecfg)
        else:
            return mcfg


    def _read_transforms(self, name):
        module_list = []
        if name not in self.cfg:
            return module_list
        cfg_mods = self.cfg[name]
        # Create 'module_list', an array of hashes
        # Where hash['mod'] = module name
        #       hash['freq'] = frequency
        #       hash['args'] = arguments
        for item in cfg_mods:
            if not item:
                continue
            if isinstance(item, (str, basestring)):
                module_list.append({
                    'mod': item.strip(),
                })
            elif isinstance(item, (list)):
                contents = {}
                # Meant to fall through...
                if len(item) >= 1:
                    contents['mod'] = item[0].strip()
                if len(item) >= 2:
                    contents['freq'] = item[1].strip()
                if len(item) >= 3:
                    contents['args'] = item[2:]
                if contents:
                    module_list.append(contents)
            else:
                raise TypeError(("Failed to read '%s' item in config,"
                                 " unknown type %s") %
                                 (item, util.obj_name(item)))
        return module_list

    def _fixup_transforms(self, raw_mods):
        mostly_mods = []
        for raw_mod in raw_mods:
            raw_name = raw_mod['mod']
            freq = raw_mod.get('freq')
            run_args = raw_mod.get('args') or []
            mod_name = transforms.form_transform_name(raw_name)
            if not mod_name:
                continue
            if freq and freq not in FREQUENCIES:
                LOG.warn(("Config specified transform %s"
                          " has an unknown frequency %s"), raw_name, freq)
                # Reset it so when ran it will get set to a known value
                freq = None
            mod = transforms.fixup_transform(importer.import_module(mod_name))
            mostly_mods.append([mod, raw_name, freq, run_args])
        return mostly_mods

    def _run_transforms(self, mostly_mods):
        failures = []
        d_name = self.init.distro.name
        c_cloud = self.init.cloudify()
        for (mod, name, freq, args) in mostly_mods:
            try:
                # Try the modules frequency, otherwise fallback to a known one
                if not freq:
                    freq = mod.frequency
                if not freq in FREQUENCIES:
                    freq = PER_INSTANCE
                worked_distros = mod.distros
                if (worked_distros and d_name not in worked_distros):
                    LOG.warn(("Transform %s is verified on %s distros"
                              " but not on %s distro. It may or may not work"
                              " correctly."), name, worked_distros, d_name)
                # Deep copy the config so that modules can't alter it
                # Use the transforms logger and not our own
                func_args = [name, copy.deepcopy(self.cfg),
                             c_cloud, transforms.LOG, args]
                # This name will affect the semaphore name created
                run_name = "config-%s" % (name)
                c_cloud.run(run_name, mod.handle, func_args, freq=freq)
            except Exception as e:
                util.logexc(LOG, "Running %s failed", mod)
                failures.append((name, e))
        return failures

    def run(self, name):
        raw_mods = self._read_transforms(name)
        mostly_mods = self._fixup_transforms(raw_mods)
        return self._run_transforms(mostly_mods)