import os
import hashlib

if False:
    from typing import Optional, List, IO, Tuple, Any

from scripts.lib.zulip_tools import subprocess_text_output, run

ZULIP_PATH = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
ZULIP_SRV_PATH = "/srv"

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


NODE_MODULES_CACHE_PATH = os.path.join(ZULIP_SRV_PATH, 'zulip-npm-cache')
YARN_BIN = os.path.join(ZULIP_SRV_PATH, 'zulip-yarn/bin/yarn')

DEFAULT_PRODUCTION = False

def get_yarn_args(production):
    # type: (bool) -> List[str]
    if production:
        yarn_args = ["--prod"]
    else:
        yarn_args = []
    return yarn_args

def generate_sha1sum_node_modules(setup_dir=None, production=DEFAULT_PRODUCTION):
    # type: (Optional[str], bool) -> str
    if setup_dir is None:
        setup_dir = os.path.realpath(os.getcwd())
    PACKAGE_JSON_FILE_PATH = os.path.join(setup_dir, 'package.json')
    YARN_LOCK_FILE_PATH = os.path.join(setup_dir, 'yarn.lock')
    sha1sum = hashlib.sha1()
    sha1sum.update(subprocess_text_output(['cat', PACKAGE_JSON_FILE_PATH]).encode('utf8'))
    if os.path.exists(YARN_LOCK_FILE_PATH):
        # For backwards compatibility, we can't assume yarn.lock exists
        sha1sum.update(subprocess_text_output(['cat', YARN_LOCK_FILE_PATH]).encode('utf8'))
    sha1sum.update(subprocess_text_output([YARN_BIN, '--version']).encode('utf8'))
    sha1sum.update(subprocess_text_output(['node', '--version']).encode('utf8'))
    yarn_args = get_yarn_args(production=production)
    sha1sum.update(''.join(sorted(yarn_args)).encode('utf8'))
    return sha1sum.hexdigest()

def setup_node_modules(production=DEFAULT_PRODUCTION, stdout=None, stderr=None, copy_modules=False,
                       prefer_offline=False):
    # type: (bool, Optional[IO[Any]], Optional[IO[Any]], bool, bool) -> None
    yarn_args = get_yarn_args(production=production)
    if prefer_offline:
        yarn_args.append("--prefer-offline")
    sha1sum = generate_sha1sum_node_modules(production=production)
    target_path = os.path.join(NODE_MODULES_CACHE_PATH, sha1sum)
    cached_node_modules = os.path.join(target_path, 'node_modules')
    success_stamp = os.path.join(target_path, '.success-stamp')
    # Check if a cached version already exists
    if not os.path.exists(success_stamp):
        do_yarn_install(target_path,
                        yarn_args,
                        success_stamp,
                        stdout=stdout,
                        stderr=stderr,
                        copy_modules=copy_modules)

    print("Using cached node modules from %s" % (cached_node_modules,))
    cmds = [
        ['rm', '-rf', 'node_modules'],
        ["ln", "-nsf", cached_node_modules, 'node_modules'],
    ]
    for cmd in cmds:
        run(cmd, stdout=stdout, stderr=stderr)

def do_yarn_install(target_path, yarn_args, success_stamp, stdout=None, stderr=None,
                    copy_modules=False):
    # type: (str, List[str], str, Optional[IO[Any]], Optional[IO[Any]], bool) -> None
    cmds = [
        ['mkdir', '-p', target_path],
        ['cp', 'package.json', "yarn.lock", target_path],
    ]
    cached_node_modules = os.path.join(target_path, 'node_modules')
    if copy_modules:
        print("Cached version not found! Copying node modules.")
        cmds.append(["cp", "-rT", "prod-static/serve/node_modules", cached_node_modules])
    else:
        print("Cached version not found! Installing node modules.")

        # Copy the existing node_modules to speed up install
        if os.path.exists("node_modules"):
            cmds.append(["cp", "-R", "node_modules/", cached_node_modules])
        cd_exec = os.path.join(ZULIP_PATH, "scripts/lib/cd_exec")
        cmds.append([cd_exec, target_path, YARN_BIN, "install", "--non-interactive"] +
                    yarn_args)
    cmds.append(['touch', success_stamp])

    for cmd in cmds:
        run(cmd, stdout=stdout, stderr=stderr)