import os
import json
import logging
import subprocess
from pipes import quote
from collections import namedtuple

logger = logging.getLogger(__name__)


# success: True or False whether call was successful
# tags: list of tags or empty list
# stdout: stdout from skopeo subprocess
# stderr: stderr from skopeo subprocess
SkopeoResults = namedtuple("SkopeoCopyResults", "success tags stdout stderr")


class SkopeoMirror(object):

  # No DB calls here: This will be called from a separate worker that has no connection except
  # to/from the mirror worker
  def copy(self, src_image, dest_image,
           src_tls_verify=True, dest_tls_verify=True,
           src_username=None, src_password=None,
           dest_username=None, dest_password=None,
           proxy=None, verbose_logs=False):

    args = ["/usr/bin/skopeo"]
    if verbose_logs:
      args = args + ["--debug"]
    args = args + ["copy",
            "--src-tls-verify=%s" % src_tls_verify,
            "--dest-tls-verify=%s" % dest_tls_verify
    ]
    args = args + self.external_registry_credentials("--dest-creds", dest_username, dest_password)
    args = args + self.external_registry_credentials("--src-creds", src_username, src_password)
    args = args + [quote(src_image), quote(dest_image)]

    return self.run_skopeo(args, proxy)


  def tags(self, repository, rule_value, username=None, password=None, tls_verify=True, proxy=None, verbose_logs=False):
    """
    Unless a specific tag is known, 'skopeo inspect' won't work. Here first 'latest' is checked
    and then the tag expression, split at commas, is each checked until one works.
    """

    args = ["/usr/bin/skopeo"]
    if verbose_logs:
      args = args + ["--debug"]
    args = args + ["inspect", "--tls-verify=%s" % tls_verify]
    args = args + self.external_registry_credentials("--creds", username, password)

    if not rule_value:
      rule_value = []

    all_tags = []
    for tag in rule_value + ["latest"]:
      result = self.run_skopeo(args + [quote("%s:%s" % (repository, tag))], proxy)

      if result.success:
        all_tags = json.loads(result.stdout)['RepoTags']
        if all_tags is not []:
          break

    return SkopeoResults(result.success, all_tags, result.stdout, result.stderr)


  def external_registry_credentials(self, arg, username, password):
    credentials = []
    if username is not None and username != '':
      if password is not None and password != '':
        creds = "%s:%s" % (username, password)
      else:
        creds = "%s" % username
      credentials = [arg, creds]

    return credentials


  def setup_env(self, proxy):
    env = os.environ.copy()

    if proxy.get("http_proxy"):
      env["HTTP_PROXY"] = proxy.get("http_proxy")
    if proxy.get("https_proxy"):
      env["HTTPS_PROXY"] = proxy.get("https_proxy")
    if proxy.get("no_proxy"):
      env["NO_PROXY"] = proxy.get("no_proxy")

    return env


  def run_skopeo(self, args, proxy):
    job = subprocess.Popen(args, shell=False, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                           env=self.setup_env(proxy), close_fds=True)

    # Poll process for new output until finished
    stdout = ""
    stderr = ""
    while True:
      stdout_nextline = job.stdout.readline()
      stdout = stdout + stdout_nextline
      stderr_nextline = job.stderr.readline()
      stderr = stderr + stderr_nextline
      if stdout_nextline == "" and stderr_nextline == "" and job.poll() is not None:
        break
      logger.debug("Skopeo [STDERR]: %s" % stderr_nextline)
      logger.debug("Skopeo [STDOUT]: %s" % stdout_nextline)

    job.communicate()

    return SkopeoResults(job.returncode == 0, [], stdout, stderr)