# 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 email
import imaplib
import os
import subprocess
import sys
import urlparse

import cliapp
import requests
import yaml


variables_filename = os.environ.get('VARIABLES', 'vars.yaml')


class YarnHelper(object):

    def __init__(self):
        self._env = dict(os.environ)
        self._next_match = 1
        self._variables = None  # None means not loaded, otherwise dict

    def set_environment(self, env):
        self._env = dict(env)

    def get_next_match(self):
        name = 'MATCH_{}'.format(self._next_match)
        if name not in self._env:
            raise Error('no next match')
        self._next_match += 1
        return self._env[name]

    def get_variable(self, name, default=None):
        if self._variables is None:
            self._variables = self._load_variables()
        return self._variables.get(name, default)

    def _load_variables(self):
        if os.path.exists(variables_filename):
            with open(variables_filename, 'r') as f:
                return yaml.safe_load(f)
        return {}

    def set_variable(self, name, value):
        if self._variables is None:
            self._variables = {}
        self._variables[name] = value
        self._save_variables(self._variables)

    def _save_variables(self, variables):
        with open(variables_filename, 'w') as f:
            yaml.safe_dump(variables, f)

    def append_to_list(self, list_name, value):
        if self._variables is None:
            self._variables = self._load_variables()
        items = self._variables.get(list_name, [])
        items.append(value)
        self.set_variable(list_name, items)

    def construct_aliased_http_request(
            self, address, method, url, data=None, headers=None):

        if headers is None:
            headers = {}

        parts = list(urlparse.urlparse(url))
        headers['Host'] = parts[1]
        parts[1] = address
        aliased_url = urlparse.urlunparse(parts)

        r = requests.Request(method, aliased_url, data=data, headers=headers)
        return r.prepare()

    def http_get(self, address, url):  # pragma: no cover
        r = self.construct_aliased_http_request(address, 'GET', url)
        s = requests.Session()
        resp = s.send(r)
        return resp.status_code, resp.content

    def assertEqual(self, a, b):
        if a != b:
            raise Error('assertion {!r} == {!r} failed'.format(a, b))

    def assertNotEqual(self, a, b):
        if a == b:
            raise Error('assertion {!r} != {!r} failed'.format(a, b))

    def assertGreaterThan(self, a, b):
        if a <= b:
            raise Error('assertion {!r} > {!r} failed'.format(a, b))

    def assertIn(self, a, b):
        if a not in b:
            raise Error('assertion {!r} in {!r} failed'.format(a, b))

    def get_password_with_pass(self, pass_home, pass_name):  # pragma: no cover
        p = subprocess.Popen(
            ['env', 'HOME={}'.format(pass_home), 'pass', 'show', pass_name],
            stdout=subprocess.PIPE)
        stdout, stderr = p.communicate()
        password = stdout.rstrip()
        return password

    def iterate_mails_in_imap_mailbox(
            self, address, user, password, callback, exp):  # pragma: no cover
        m = imaplib.IMAP4_SSL(address)
        m.login(user, password)
        m.select('INBOX', False)
        typ, data = m.search(None, 'ALL')
        for num in data[0].split():
            typ, data = m.fetch(num, '(RFC822)')
            typ, text = data[0]
            msg = email.message_from_string(text)
            callback(m, num, msg)
        if exp:
            m.expunge()
        m.close()
        m.logout()

    def ssh_keygen(self, user):  # pragma: no cover
        filename = self.ssh_key_file_for_user(user)
        cliapp.runcmd(['ssh-keygen', '-f', filename, '-N', '', '-C', user])
        with open(filename + '.pub') as f:
            return f.read()

    def ssh_key_file_for_user(self, user):  # pragma: no cover
        return os.path.abspath('{}.key'.format(user))

    def repo_ssh_url(self, repo):  # pragma: no cover
        return 'ssh://git@{}/{}'.format(os.environ['GITANO_SERVER'], repo)

    def local_checkout_dirname(self, user, repo):  # pragma: no cover
        return '{}_{}'.format(user, repo)

    def git_as(self, user, args, **kwargs):  # pragma: no cover
        server = os.environ['GITANO_SERVER']
        env = dict(os.environ)
        env['GIT_SSH_COMMAND'] = self.env_ssh_command(user)
        sys.stdout.write('env:\n')
        for key in env:
            sys.stdout.write('  {}={}\n'.format(key, env[key]))
        sys.stdout.write('git args: {}\n'.format(args))
        return cliapp.runcmd_unchecked(
            ['git'] + args,
            stderr=subprocess.STDOUT,
            env=env,
            **kwargs)

    def git_as_checked(self, user, args, **kwargs):  # pragma: no cover
        exit, out, err = self.git_as(user, args, **kwargs)
        sys.stdout.write('STDOUT from git:\n{}'.format(out))
        sys.stderr.write('STDERR from git:\n{}'.format(err))
        self.assertEqual(exit, 0)
    
    def env_ssh_command(self, user):  # pragma: no cover
        argv = [
            'ssh',
            '-o', 'PasswordAuthentication=no',
            '-o', 'IdentitiesOnly=yes',
            '-i', self.get_user_ssh_key(user),
        ]
        return ' '.join(argv)

    def get_admin_ssh_key(self):  # pragma: no cover
        return os.environ['ADMIN_SSH_KEY']

    def get_user_ssh_key(self, user):  # pragma: no cover
        if user is None:
            return self.get_admin_ssh_key()
        else:
            return self.ssh_key_file_for_user(user)

    def gitano(self, user, args, stdin=None):  # pragma: no cover
        server = os.environ['GITANO_SERVER']
        kwargs = {
            'stderr': subprocess.STDOUT,
            'ssh_options': [
                '-oPasswordAuthentication=no',
                '-oIdentitiesOnly=yes',
                '-i', self.get_user_ssh_key(user),
            ],
        }
        if stdin is not None:
            kwargs['feed_stdin'] = stdin
        return cliapp.ssh_runcmd(
            'git@{}'.format(server),
            args.split(),
            **kwargs)

    def gitano_confirm_with_token(self, prefix, which):  # pragma: no cover
        try:
            output = self.gitano(None, '{} {}'.format(prefix, which))
        except cliapp.AppException:
            pass
        else:
            last_line = output.splitlines()[-1]
            token = last_line.split()[-1]
            self.gitano(None, '{} {} {}'.format(prefix, which, token))


class Error(Exception):

    pass