# Copyright (C) 2018  Lars Wirzenius
# 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 base64
import json
import logging
import os
import tempfile


import ick2


class UnknownStepError(Exception):

    pass


class ActionFactory:

    _classes = {
        'host': ick2.HostEnvironment,
        'chroot': ick2.ChrootEnvironment,
        'container': ick2.ContainerEnvironment,
    }

    def __init__(self, systree, workspace_area, reporter):
        self._systree = systree
        self._workspace_area = workspace_area
        self._reporter = reporter
        self._token = None
        self._blob_url = None
        self._extra_env = {}

    def add_env_var(self, name, value):  # pragma: no cover
        self._extra_env[name] = value

    def set_token(self, token):
        self._token = token

    def get_token(self):
        return self._token

    def set_blob_url_func(self, func):
        self._blob_url = func

    def get_blob_url_func(self):
        return self._blob_url

    def get_allowed_environments(self):
        return list(self._classes.keys())

    def get_workspace_area(self):
        area = ick2.WorkspaceArea()
        area.set_root(self._workspace_area)
        return area

    def create_environment(self, spec, project_name):
        env = spec.get('where', 'host')
        assert env in self.get_allowed_environments()
        env_class = self._classes[env]
        area = self.get_workspace_area()
        ws = area.create_workspace(project_name)
        env = env_class(self._systree, ws.get_directory(), self._reporter)
        env.set_extra_env(self._extra_env)
        return env

    def create_action(self, spec, project_name):
        env = self.create_environment(spec, project_name)
        action = self._create_action_object(env, spec)
        action.set_token(self.get_token())
        action.set_blob_url_func(self.get_blob_url_func())
        return action

    def _create_action_object(self, env, spec):
        if 'shell' in spec:
            return ShellAction(env)
        if 'python' in spec:
            return PythonAction(env)
        if 'debootstrap' in spec:
            return DebootstrapAction(env)
        if 'archive' in spec:
            return ArchiveWorkspaceAction(env)
        if spec.get('action') == 'populate_systree':
            return PopulateSystreeAction(env)
        if spec.get('action') == 'create_workspace':
            return CreateWorkspaceAction(env)
        raise UnknownStepError('Unknown action %r' % spec)


class Action:  # pragma: no cover

    def __init__(self, env):
        self._env = env
        self._token = None
        self._blob_url = None

    def set_token(self, token):
        self._token = token

    def get_token(self):
        return self._token

    def set_blob_url_func(self, func):
        self._blob_url = func

    def get_blob_upload_url(self, blob_name):
        return self._blob_url(blob_name)

    def get_env(self):
        return self._env

    def get_workspace_area(self):
        env = self.get_env()
        area = ick2.WorkspaceArea()
        area.set_root(env.get_workspace_directory())
        return area

    def encode_parameters(self, parsms):
        raise NotImplementedError()

    def encode64(self, params):
        assert isinstance(params, dict)
        as_text = json.dumps(params)
        as_bytes = as_text.encode('UTF-8')
        as_base64 = base64.b64encode(as_bytes)
        return as_base64.decode('UTF-8')

    def decode64(self, encoded):
        as_base64 = encoded.encode('UTF-8')
        as_bytes = base64.b64decode(as_base64)
        as_text = as_bytes.decode('UTF-8')
        return json.loads(as_text)

    def get_authz_headers(self):
        token = self.get_token()
        return {
            'Authorization': 'Bearer {}'.format(token),
        }

    def execute(self, params, step):
        raise NotImplementedError()


class ShellAction(Action):

    def encode_parameters(self, params):  # pragma: no cover
        encoded = self.encode64(params)
        return 'params() { echo -n "%s" | base64 -d; }\n' % encoded

    def execute(self, params, step):
        prefix = self.encode_parameters(params)
        snippet = step['shell']
        argv = ['bash', '-exuc', prefix + snippet]
        exit_code = self._env.runcmd(argv)
        self._env.report(exit_code, 'action finished\n')
        return exit_code


class PythonAction(Action):

    def encode_parameters(self, params):  # pragma: no cover
        encoded = self.encode64(params)
        prefix = (
            'import base64, json\n'
            'params = json.loads(base64.b64decode(\n'
            '  "{}").decode("utf8"))\n'
        ).format(encoded)
        return prefix

    def execute(self, params, step):
        prefix = self.encode_parameters(params)
        snippet = step['python']
        argv = ['python3', '-c', prefix + '\n' + snippet]
        exit_code = self._env.runcmd(argv)
        self._env.report(exit_code, 'action finished\n')
        return exit_code


class DebootstrapAction(Action):

    default_mirror = 'http://deb.debian.org/debian'

    def encode_parameters(self, params):  # pragma: no cover
        pass

    def execute(self, params, step):
        suite = step.get('debootstrap')
        if suite is None or suite == 'auto':
            suite = params['debian_codename']
        mirror = step.get('mirror', self.default_mirror)

        env = self.get_env()
        workspace = env.get_workspace_directory()
        argv = ['sudo', 'debootstrap', suite, '.', mirror]
        exit_code = self._env.host_runcmd(argv, cwd=workspace)
        self._env.report(exit_code, 'action finished\n')
        return exit_code


class CreateWorkspaceAction(Action):

    def encode_parameters(self, params):  # pragma: no cover
        pass

    def execute(self, params, step):
        env = self.get_env()
        dirname = env.get_workspace_directory()
        make_directory_empty(env, dirname)
        self._env.report(0, 'Created or emptied workspace %s\n' % dirname)
        return 0


class ArchiveWorkspaceAction(Action):  # pragma: no cover

    def encode_parameters(self, params):
        pass

    def execute(self, params, step):
        blob_name = params.get('systree_name', 'noname')

        env = self.get_env()
        dirname = env.get_workspace_directory()

        url = self.get_blob_upload_url(blob_name)
        headers = self.get_authz_headers()

        fd, tarball = tempfile.mkstemp()
        os.close(fd)
        tar = ['sudo', 'tar', '-zcf', tarball, '-C', dirname, '.']
        exit_code = self._env.host_runcmd(tar)
        if exit_code != 0:
            self._env.report(exit_code, 'tarball generation finished\n')
            os.remove(tarball)
            return exit_code
        self._env.report(None, 'tarball generation finished\n')

        curl = ['curl', '-sk', '-T', tarball] + [
            '-H{}:{}'.format(name, value)
            for name, value in headers.items()
        ] + [url]
        exit_code = self._env.host_runcmd(curl)
        self._env.report(
            exit_code, 'curl upload finished (exit code %s)\n' % exit_code)
        os.remove(tarball)
        return exit_code


class PopulateSystreeAction(Action):  # pragma: no cover

    def encode_parameters(self, params):
        pass

    def execute(self, params, step):
        systree_name = step.get('systree_name')
        if not systree_name or systree_name == 'auto':
            systree_name = params['systree_name']
            logging.info(
                'No systree name or it is "auto", using %s', systree_name)

        env = self.get_env()
        systree_dir = env.get_systree_directory()
        make_directory_empty(env, systree_dir)
        return self.download_and_unpack_systree(systree_name, systree_dir)

    def download_and_unpack_systree(self, systree_name, dirname):
        url = self.get_blob_upload_url(systree_name)
        headers = self.get_authz_headers()
        curl = ['curl', '-sk'] + [
            '-H{}:{}'.format(name, value)
            for name, value in headers.items()
        ] + [url]

        untar = ['sudo', 'tar', '-zxf', '-', '-C', dirname]

        exit_code = self._env.host_runcmd(curl, untar)
        self._env.report(exit_code, 'action finished\n')
        return exit_code


def make_directory_empty(env, dirname):
    return env.runcmd(
        ['sudo', 'find', dirname, '-mindepth', '1', '-delete'])