import json
import os
import subprocess

from os.path import join as join_path
from ucloud.config import etcd_client, config, image_storage_handler
from ucloud.imagescanner import logger


def qemu_img_type(path):
    qemu_img_info_command = ["qemu-img", "info", "--output", "json", path]
    try:
        qemu_img_info = subprocess.check_output(qemu_img_info_command)
    except Exception as e:
        logger.exception(e)
        return None
    else:
        qemu_img_info = json.loads(qemu_img_info.decode("utf-8"))
        return qemu_img_info["format"]

def check():
    """ check whether settings are sane, refuse to start if they aren't """
    if config['etcd']['STORAGE_BACKEND'] == 'filesystem' and not isdir(config['etcd']['IMAGE_DIR']):
        print("You have set STORAGE_BACKEND to filesystem, but "
              "{} does not exist. Refusing to start".format(config['etcd']['IMAGE_DIR']))
        sys.exit(1)

    try:
        subprocess.check_output(['which', 'qemu-img'])
    except Exception:
        print("qemu-img missing")
        sys.exit(1)


def main():
    # We want to get images entries that requests images to be created
    images = etcd_client.get_prefix(config['etcd']['IMAGE_PREFIX'], value_in_json=True)
    images_to_be_created = list(filter(lambda im: im.value['status'] == 'TO_BE_CREATED', images))

    for image in images_to_be_created:
        try:
            image_uuid = image.key.split('/')[-1]
            image_owner = image.value['owner']
            image_filename = image.value['filename']
            image_store_name = image.value['store_name']
            image_full_path = join_path(config['etcd']['BASE_DIR'], image_owner, image_filename)

            image_stores = etcd_client.get_prefix(config['etcd']['IMAGE_STORE_PREFIX'], value_in_json=True)
            user_image_store = next(filter(
                lambda s, store_name=image_store_name: s.value["name"] == store_name,
                image_stores
            ))

            image_store_pool = user_image_store.value['attributes']['pool']

        except Exception as e:
            logger.exception(e)
        else:
            # At least our basic data is available
            qemu_img_convert_command = ["qemu-img", "convert", "-f", "qcow2",
                                        "-O", "raw", image_full_path, "image.raw"]

            if qemu_img_type(image_full_path) == "qcow2":
                try:
                    # Convert .qcow2 to .raw
                    subprocess.check_output(qemu_img_convert_command)
                except Exception as e:
                    logger.exception(e)
                else:
                    # Import and Protect
                    r_status = image_storage_handler.import_image(src="image.raw",
                                                                  dest=image_uuid,
                                                                  protect=True)
                    if r_status:
                        # Everything is successfully done
                        image.value["status"] = "CREATED"
                        etcd_client.put(image.key, json.dumps(image.value))

            else:
                # The user provided image is either not found or of invalid format
                image.value["status"] = "INVALID_IMAGE"
                etcd_client.put(image.key, json.dumps(image.value))

        try:
            os.remove("image.raw")
        except Exception:
            pass


if __name__ == "__main__":
    main()