# Copyright 2017  Lars Wirzenius
#
# This program 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, either version 3 of the License, or
# (at your option) any later version.
#
# 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/>.
#
# =*= License: GPL-3+ =*=

import logging
import os
import tempfile

import vmdb


class MountPlugin(vmdb.Plugin):
    def enable(self):
        self.app.step_runners.add(MountStepRunner())


class MountStepRunner(vmdb.StepRunnerInterface):
    def get_key_spec(self):
        return {"mount": str, "dirname": "", "mount-on": "", "zerofree": True, "keep_resolvconf": False}

    def run(self, values, settings, state):
        self.mount_rootfs(values, settings, state)

    def teardown(self, values, settings, state):
        self.unmount_rootfs(values, settings, state)
        tag = values["mount"]
        run_zerofree = values.get("zerofree", True)
        if run_zerofree:
            fstype = state.tags.get_fstype(tag)
            if fstype.startswith("ext"):
                dev = state.tags.get_dev(tag)
                vmdb.runcmd(["zerofree", dev])
                vmdb.runcmd(["sync"])
            else:
                logging.info(f"not running zerofree on {tag} with {fstype} filesystem")

    def mount_rootfs(self, values, settings, state):
        tag = values["mount"]
        dirname = values["dirname"] or None
        mount_on = values["mount-on"] or None

        device = state.tags.get_dev(tag)

        if dirname:
            if not mount_on:
                raise Exception("no mount-on tag given")

            if not state.tags.has_tag(mount_on):
                raise Exception("cannot find tag {}".format(mount_on))

            mount_point = os.path.normpath(
                os.path.join(
                    state.tags.get_builder_mount_point(mount_on), "./" + dirname
                )
            )

            if not os.path.exists(mount_point):
                os.makedirs(mount_point)
        else:
            dirname = "/"
            mount_point = tempfile.mkdtemp()

        vmdb.runcmd(["mount", device, mount_point])
        state.tags.set_builder_mount_point(tag, mount_point, cached=True)
        state.tags.set_target_mount_point(tag, dirname)

        # detect the filesystem and uuid if they are not already known. This
        # will be the case if the tags were defined via the kpartx plugin,
        # rather than by the mkfs plugin
        if not state.tags.get_fstype(tag):
            fstype = (
                vmdb.runcmd(["blkid", "-c/dev/null", "-ovalue", "-sTYPE", device])
                .decode()
                .strip()
            )
            state.tags.set_fstype(tag, fstype)
            uuid = state.tags.get_fsuuid(tag)
            if not uuid:
                uuid = (
                    vmdb.runcmd(["blkid", "-c/dev/null", "-ovalue", "-sUUID", device])
                    .decode()
                    .strip()
                )
                state.tags.set_fsuuid(tag, uuid)

        return mount_point

    def unmount_rootfs(self, values, settings, state):
        tag = values["mount"]
        mount_point = state.tags.get_builder_mount_point(tag)
        if mount_point is None:
            return

        keep_resolvconf = values.get("keep_resolvconf", False)

        resolv_conf = os.path.join(mount_point, "etc/resolv.conf")
        if os.path.exists(resolv_conf) and not keep_resolvconf:
            os.remove(resolv_conf)

        try:
            vmdb.unmount(mount_point)
        except vmdb.NotMounted as e:
            logging.warning(str(e))

        if not values["mount-on"]:
            os.rmdir(mount_point)
