import logging
import sys
import threading

import cwltool.docker
from cwltool.errors import WorkflowException
import arvados.commands.keepdocker

logger = logging.getLogger('arvados.cwl-runner')

cached_lookups = {}
cached_lookups_lock = threading.Lock()

def arv_docker_get_image(api_client, dockerRequirement, pull_image, project_uuid):
    """Check if a Docker image is available in Keep, if not, upload it using arv-keepdocker."""

    if "dockerImageId" not in dockerRequirement and "dockerPull" in dockerRequirement:
        dockerRequirement["dockerImageId"] = dockerRequirement["dockerPull"]

    global cached_lookups
    global cached_lookups_lock
    with cached_lookups_lock:
        if dockerRequirement["dockerImageId"] in cached_lookups:
            return cached_lookups[dockerRequirement["dockerImageId"]]

    sp = dockerRequirement["dockerImageId"].split(":")
    image_name = sp[0]
    image_tag = sp[1] if len(sp) > 1 else None

    images = arvados.commands.keepdocker.list_images_in_arv(api_client, 3,
                                                            image_name=image_name,
                                                            image_tag=image_tag)

    if not images:
        # Fetch Docker image if necessary.
        cwltool.docker.get_image(dockerRequirement, pull_image)

        # Upload image to Arvados
        args = []
        if project_uuid:
            args.append("--project-uuid="+project_uuid)
        args.append(image_name)
        if image_tag:
            args.append(image_tag)
        logger.info("Uploading Docker image %s", ":".join(args[1:]))
        try:
            arvados.commands.keepdocker.main(args, stdout=sys.stderr)
        except SystemExit as e:
            if e.code:
                raise WorkflowException("keepdocker exited with code %s" % e.code)

        images = arvados.commands.keepdocker.list_images_in_arv(api_client, 3,
                                                                image_name=image_name,
                                                                image_tag=image_tag)

    if not images:
        raise WorkflowException("Could not find Docker image %s:%s" % (image_name, image_tag))

    pdh = api_client.collections().get(uuid=images[0][0]).execute()["portable_data_hash"]

    with cached_lookups_lock:
        cached_lookups[dockerRequirement["dockerImageId"]] = pdh

    return pdh

def arv_docker_clear_cache():
    global cached_lookups
    global cached_lookups_lock
    with cached_lookups_lock:
        cached_lookups = {}