from __future__ import print_function

import os
import sys
from os.path import dirname, abspath
import subprocess
from scripts.lib.zulip_tools import run

ZULIP_PATH = dirname(dirname(dirname(abspath(__file__))))
VENV_CACHE_PATH = "/srv/zulip-venv-cache"

if 'TRAVIS' in os.environ:
    # In Travis CI, we don't have root access
    VENV_CACHE_PATH = "/home/travis/zulip-venv-cache"

if False:
    # Don't add a runtime dependency on typing
    from typing import List, Optional

VENV_DEPENDENCIES = [
    "build-essential",
    "libffi-dev",
    "libfreetype6-dev",     # Needed for image types with Pillow
    "libz-dev",             # Needed to handle compressed PNGs with Pillow
    "libjpeg-dev",          # Needed to handle JPEGs with Pillow
    "libldap2-dev",
    "libmemcached-dev",
    "python3-dev",          # Needed to install typed-ast dependency of mypy
    "python-dev",
    "python-pip",
    "python-virtualenv",
    "libxml2-dev",          # Used for installing talon
    "libxslt1-dev",         # Used for installing talon
    "libpq-dev",            # Needed by psycopg2
]

def do_patch_activate_script(venv_path):
    # type: (str) -> None
    """
    Patches the bin/activate script so that the value of the environment variable VIRTUAL_ENV
    is set to venv_path during the script's execution whenever it is sourced.
    """
    # venv_path should be what we want to have in VIRTUAL_ENV after patching
    script_path = os.path.join(venv_path, "bin", "activate")

    file_obj = open(script_path)
    lines = file_obj.readlines()
    for i, line in enumerate(lines):
        if line.startswith('VIRTUAL_ENV='):
            lines[i] = 'VIRTUAL_ENV="%s"\n' % (venv_path,)
    file_obj.close()

    file_obj = open(script_path, 'w')
    file_obj.write("".join(lines))
    file_obj.close()

def setup_virtualenv(target_venv_path, requirements_file, virtualenv_args=None, patch_activate_script=False):
    # type: (Optional[str], str, Optional[List[str]], bool) -> str

    # Check if a cached version already exists
    path = os.path.join(ZULIP_PATH, 'scripts', 'lib', 'hash_reqs.py')
    output = subprocess.check_output([path, requirements_file], universal_newlines=True)
    sha1sum = output.split()[0]
    if target_venv_path is None:
        cached_venv_path = os.path.join(VENV_CACHE_PATH, sha1sum, 'venv')
    else:
        cached_venv_path = os.path.join(VENV_CACHE_PATH, sha1sum, os.path.basename(target_venv_path))
    success_stamp = os.path.join(cached_venv_path, "success-stamp")
    if not os.path.exists(success_stamp):
        do_setup_virtualenv(cached_venv_path, requirements_file, virtualenv_args or [])
        run(["touch", success_stamp])

    print("Using cached Python venv from %s" % (cached_venv_path,))
    if target_venv_path is not None:
        run(["sudo", "ln", "-nsf", cached_venv_path, target_venv_path])
        if patch_activate_script:
            do_patch_activate_script(target_venv_path)
    activate_this = os.path.join(cached_venv_path, "bin", "activate_this.py")
    exec(open(activate_this).read(), {}, dict(__file__=activate_this)) # type: ignore # https://github.com/python/mypy/issues/1577
    return cached_venv_path

def do_setup_virtualenv(venv_path, requirements_file, virtualenv_args):
    # type: (str, str, List[str]) -> None

    # Setup Python virtualenv
    run(["sudo", "rm", "-rf", venv_path])
    run(["sudo", "mkdir", "-p", venv_path])
    run(["sudo", "chown", "{}:{}".format(os.getuid(), os.getgid()), venv_path])
    run(["virtualenv"] + virtualenv_args + [venv_path])

    # Switch current Python context to the virtualenv.
    activate_this = os.path.join(venv_path, "bin", "activate_this.py")
    exec(open(activate_this).read(), {}, dict(__file__=activate_this)) # type: ignore # https://github.com/python/mypy/issues/1577

    run(["pip", "install", "-U", "setuptools"])
    run(["pip", "install", "--upgrade", "pip", "wheel"])
    run(["pip", "install", "--no-deps", "--requirement", requirements_file])
    run(["sudo", "chmod", "-R", "a+rX", venv_path])