# Copyright © 2022 Aravinth Manivannan <realaravinth@batsense.net>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
import os
import shutil
from pathlib import Path

from django.utils.crypto import get_random_string
from django.template.loader import render_to_string
from django.conf import settings
from git import Repo
from git.exc import InvalidGitRepositoryError

from dash.models import Instance

from .models import InstanceCreated


def create_vm_if_not_exists(instance: Instance):
    infra = Infra()
    if not InstanceCreated.objects.filter(instance=instance).exists():
        gitea_password = infra.add_vm(instance=instance)
        instance = InstanceCreated.objects.create(
            instance=instance, gitea_password=gitea_password, created=True
        )
        instance.save()


def delete_vm(instance: Instance, owner: str):
    infra = Infra()
    infra.remove_vm(instance=instance)
    if InstanceCreated.objects.filter(instance=instance).exists():
        InstanceCreated.objects.get(instance=instance).delete()
    instance.delete()


class Infra:
    """
    Utility function to manage infrastructure repository
    """

    def __init__(self):
        conf = settings.HOSTEA["INFRA"]["HOSTEA_REPO"]
        self.repo_path = Path(conf["PATH"])
        if not self.repo_path.exists():
            os.makedirs(self.repo_path)

        ssh_cmd = f"/usr/bin/ssh -oStrictHostKeyChecking=no -i {conf['SSH_KEY']}"
        self.env = {"GIT_SSH_COMMAND": ssh_cmd}
        try:
            self.repo = Repo(path=self.repo_path)
        except InvalidGitRepositoryError:
            self.repo = Repo.clone_from(conf["REMOTE"], self.repo_path, env=self.env)

    def _host_vars_dir(self, subdomain: str) -> Path:
        """
        utility method: get host_vars directory for a subdomain
        """
        return self.repo_path.joinpath(f"inventory/host_vars/{subdomain}-host/")

    def _provision_path(self, subdomain: str) -> Path:
        """
        utility method: get provision file pay for a subdomain
        """

        return self._host_vars_dir(subdomain=subdomain).joinpath("provision.yml")

    def _gitea_path(self, subdomain: str) -> Path:
        """
        utility method: get gitea file for a subdomain
        """

        return self._host_vars_dir(subdomain=subdomain).joinpath("gitea.yml")

    def _backup_path(self, subdomain: str) -> Path:
        """
        utility method: get backup file for a subdomain
        """

        return self.repo_path.joinpath(f"inventory/{subdomain}-backup.yml")

    def _service_path(self, subdomain: str) -> Path:
        """
        utility method: get service file for a subdomain
        """

        return self.repo_path.joinpath(f"inventory/{subdomain}-service.yml")

    def _hostscript_path(self, subdomain: str) -> Path:
        """
        utility method: hostscript file for a subdomain
        """
        path = self.repo_path.joinpath(f"hosts-scripts/{subdomain}-host.sh")
        return path

    def write_hostscript(self, subdomain: str, content: str):
        """
        Write contents to hostscript.
        Hostscript will contain the history of all actions that have been
        ordered on a particular VM. So content needs to be appended to it,
        rather than overwritten.
        """
        hostscript = self._hostscript_path(subdomain)
        with open(hostscript, "a", encoding="utf-8") as f:
            f.write(content)
            f.write("\n")

    def _add_files(self, subdomain: str):
        """
        Add all relevant files of a VM
        """
        self.repo.git.add(str(self._host_vars_dir(subdomain=subdomain)))
        self.repo.git.add(str(self._backup_path(subdomain=subdomain)))
        self.repo.git.add(str(self._service_path(subdomain=subdomain)))
        self.repo.git.add(str(self._hostscript_path(subdomain=subdomain)))

    def _commit(self, action: str, subdomain: str):
        """
        Commit changes to a VM configuration
        """

        self._add_files(subdomain=subdomain)
        self.repo.git.commit(
            message=f"{action} VM {subdomain}",
            author="Dashboard Bot <bot@dashboard.hostea.org>",
        )

    def _pull(self):
        self.repo.git.pull(env=self.env, rebase="true")

    def add_vm(self, instance: Instance) -> str:
        """
        Add new VM to infrastructure repository

        The gitea user password is returned
        """
        self._pull()

        subdomain = instance.name
        host_vars_dir = self._host_vars_dir(subdomain)

        if not host_vars_dir.exists():
            os.makedirs(host_vars_dir)

        hostscript_path = self.repo_path.joinpath("hosts-scripts/")
        if not hostscript_path.exists():
            os.makedirs(hostscript_path)

        woodpecker_agent_secret = get_random_string(64)
        gitea_password = get_random_string(20)

        ctx = {
            "woodpecker_agent_secret": woodpecker_agent_secret,
            "woodpecker_hostname": f"{subdomain}-ci",
            "woodpecker_admins": f"{instance.owned_by.username}",
            "gitea_email": instance.owned_by.email,
            "gitea_password": gitea_password,
            "subdomain": subdomain,
        }

        gitea = self._gitea_path(subdomain)
        with open(gitea, "w", encoding="utf-8") as f:
            f.write(
                render_to_string(
                    "infrastructure/yml/gitea.yml",
                    context=ctx,
                )
            )

        # provision_template = "./templates/infrastructure/yml/provision.yml"
        provision = self._provision_path(subdomain)
        # TODO: instance config names are different the flavours expected:
        # ```
        # openstack_flavor: ‘{{ openstack_flavor_medium }}’ * openstack_flavor: ‘{{ openstack_flavor_large }}’
        # ```
        # check with @dachary about this

        size = None
        if instance.configuration_id.name == "s1-2":
            size = "openstack_flavor_small"
        elif instance.configuration_id.name == "s1-4":
            size = "openstack_flavor_medium"
        elif instance.configuration_id.name == "s1-8":
            size = "openstack_flavor_large"
        else:
            size = instance.configuration_id.name

        with open(provision, "w", encoding="utf-8") as f:
            f.write(
                render_to_string(
                    "infrastructure/yml/provision.yml", context={"vm_size": size}
                )
            )

        # backup = self.repo_path.joinpath(f"inventory/{instance.name}-backup.yml")
        backup = self._backup_path(subdomain)
        #        backup_template = "./templates/infrastructure/yml/provision.yml"
        with open(backup, "w", encoding="utf-8") as f:
            f.write(
                render_to_string(
                    "infrastructure/yml/backups.yml", context={"subdomain": subdomain}
                )
            )

        service = self._service_path(subdomain)
        with open(service, "w", encoding="utf-8") as f:
            f.write(
                render_to_string(
                    "infrastructure/yml/service.yml", context={"subdomain": subdomain}
                )
            )

        # hostscript = self.repo_path.join("inventory/hosts-scripts/{instance.name}-host.sh")

        hostscript = self._hostscript_path(subdomain)
        with open(hostscript, "w", encoding="utf-8") as f:
            f.write("\n")

        self.write_hostscript(
            subdomain=subdomain,
            content=render_to_string(
                "infrastructure/sh/hostscripts/create.sh",
                context={"subdomain": subdomain},
            ),
        )

        self._commit(action="add", subdomain=subdomain)
        self.repo.git.push(env=self.env)
        return gitea_password

    def remove_vm(self, instance: Instance):
        """
        Remove a VM from infrastructure repository
        """
        self._pull()
        subdomain = instance.name

        host_vars_dir = self._host_vars_dir(subdomain)
        shutil.rmtree(host_vars_dir)

        backup = self._backup_path(subdomain)
        os.remove(backup)

        service = self._service_path(subdomain)
        os.remove(service)

        hostscript = self._hostscript_path(subdomain)
        with open(hostscript, "w", encoding="utf-8") as f:
            f.write("\n")

        self.write_hostscript(
            subdomain=subdomain,
            content=render_to_string(
                "infrastructure/sh/hostscripts/rm.sh",
                context={"subdomain": subdomain},
            ),
        )
        self._commit(action="rm", subdomain=subdomain)
        self.repo.git.push(env=self.env)