from __future__ import absolute_import
from __future__ import unicode_literals

import logging

from docker.errors import NotFound
from docker.utils import version_lt

from .config import ConfigurationError
from .config.types import VolumeSpec
from .const import LABEL_PROJECT
from .const import LABEL_VOLUME

log = logging.getLogger(__name__)


class Volume(object):
    def __init__(self, client, project, name, driver=None, driver_opts=None,
                 external=False, labels=None, custom_name=False):
        self.client = client
        self.project = project
        self.name = name
        self.driver = driver
        self.driver_opts = driver_opts
        self.external = external
        self.labels = labels
        self.custom_name = custom_name

    def create(self):
        return self.client.create_volume(
            self.full_name, self.driver, self.driver_opts, labels=self._labels
        )

    def remove(self):
        if self.external:
            log.info("Volume %s is external, skipping", self.full_name)
            return
        log.info("Removing volume %s", self.full_name)
        return self.client.remove_volume(self.full_name)

    def inspect(self):
        return self.client.inspect_volume(self.full_name)

    def exists(self):
        try:
            self.inspect()
        except NotFound:
            return False
        return True

    @property
    def full_name(self):
        if self.custom_name:
            return self.name
        return '{0}_{1}'.format(self.project, self.name)

    @property
    def _labels(self):
        if version_lt(self.client._version, '1.23'):
            return None
        labels = self.labels.copy() if self.labels else {}
        labels.update({
            LABEL_PROJECT: self.project,
            LABEL_VOLUME: self.name,
        })
        return labels


class ProjectVolumes(object):

    def __init__(self, volumes):
        self.volumes = volumes

    @classmethod
    def from_config(cls, name, config_data, client):
        config_volumes = config_data.volumes or {}
        volumes = {
            vol_name: Volume(
                client=client,
                project=name,
                name=data.get('name', vol_name),
                driver=data.get('driver'),
                driver_opts=data.get('driver_opts'),
                custom_name=data.get('name') is not None,
                labels=data.get('labels'),
                external=bool(data.get('external', False))
            )
            for vol_name, data in config_volumes.items()
        }
        return cls(volumes)

    def remove(self):
        for volume in self.volumes.values():
            try:
                volume.remove()
            except NotFound:
                log.warn("Volume %s not found.", volume.full_name)

    def initialize(self):
        try:
            for volume in self.volumes.values():
                volume_exists = volume.exists()
                if volume.external:
                    log.debug(
                        'Volume {0} declared as external. No new '
                        'volume will be created.'.format(volume.name)
                    )
                    if not volume_exists:
                        raise ConfigurationError(
                            'Volume {name} declared as external, but could'
                            ' not be found. Please create the volume manually'
                            ' using `{command}{name}` and try again.'.format(
                                name=volume.full_name,
                                command='docker volume create --name='
                            )
                        )
                    continue

                if not volume_exists:
                    log.info(
                        'Creating volume "{0}" with {1} driver'.format(
                            volume.full_name, volume.driver or 'default'
                        )
                    )
                    volume.create()
                else:
                    check_remote_volume_config(volume.inspect(), volume)
        except NotFound:
            raise ConfigurationError(
                'Volume %s specifies nonexistent driver %s' % (volume.name, volume.driver)
            )

    def namespace_spec(self, volume_spec):
        if not volume_spec.is_named_volume:
            return volume_spec

        if isinstance(volume_spec, VolumeSpec):
            volume = self.volumes[volume_spec.external]
            return volume_spec._replace(external=volume.full_name)
        else:
            volume_spec.source = self.volumes[volume_spec.source].full_name
            return volume_spec


class VolumeConfigChangedError(ConfigurationError):
    def __init__(self, local, property_name, local_value, remote_value):
        super(VolumeConfigChangedError, self).__init__(
            'Configuration for volume {vol_name} specifies {property_name} '
            '{local_value}, but a volume with the same name uses a different '
            '{property_name} ({remote_value}). If you wish to use the new '
            'configuration, please remove the existing volume "{full_name}" '
            'first:\n$ docker volume rm {full_name}'.format(
                vol_name=local.name, property_name=property_name,
                local_value=local_value, remote_value=remote_value,
                full_name=local.full_name
            )
        )


def check_remote_volume_config(remote, local):
    if local.driver and remote.get('Driver') != local.driver:
        raise VolumeConfigChangedError(local, 'driver', local.driver, remote.get('Driver'))
    local_opts = local.driver_opts or {}
    remote_opts = remote.get('Options') or {}
    for k in set.union(set(remote_opts.keys()), set(local_opts.keys())):
        if k.startswith('com.docker.'):  # These options are set internally
            continue
        if remote_opts.get(k) != local_opts.get(k):
            raise VolumeConfigChangedError(
                local, '"{}" driver_opt'.format(k), local_opts.get(k), remote_opts.get(k),
            )

    local_labels = local.labels or {}
    remote_labels = remote.get('Labels') or {}
    for k in set.union(set(remote_labels.keys()), set(local_labels.keys())):
        if k.startswith('com.docker.'):  # We are only interested in user-specified labels
            continue
        if remote_labels.get(k) != local_labels.get(k):
            log.warn(
                'Volume {}: label "{}" has changed. It may need to be'
                ' recreated.'.format(local.name, k)
            )