# Copyright 2019 Antonio Terceiro
#
# 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 os

import vmdb


class FstabPlugin(vmdb.Plugin):
    def enable(self):
        self.app.step_runners.add(FstabStepRunner())


class FstabStepRunner(vmdb.StepRunnerInterface):
    def get_key_spec(self):
        return {"fstab": str}

    def run(self, values, setting, state):
        tag = values["fstab"]
        chroot = state.tags.get_builder_mount_point(tag)

        filesystems = []

        for tag in state.tags.get_tags():
            device = state.tags.get_dev(tag)
            mount_point = state.tags.get_target_mount_point(tag)
            if mount_point is not None:
                fstype = state.tags.get_fstype(tag)
                output = vmdb.runcmd(
                    ["blkid", "-c", "/dev/null", "-o", "value", "-s", "UUID", device]
                )
                if output:
                    uuid = output.decode().strip()
                    filesystems.append(
                        {"uuid": uuid, "mount_point": mount_point, "fstype": fstype}
                    )
                else:
                    raise Exception(
                        "Unknown UUID for device {} (to be mounted on {})".format(
                            device, mount_point
                        )
                    )

        fstab_path = os.path.join(chroot, "etc/fstab")
        line = "UUID={uuid} {mount_point} {fstype} errors=remount-ro 0 1\n"
        with open(fstab_path, "w") as fstab:
            for entry in filesystems:
                fstab.write(line.format(**entry))