import json
import os
import subprocess as sp
import sys

from os.path import isdir
from os.path import join as join_path
from ucloud.settings import settings
from ucloud.shared import shared
from ucloud.imagescanner import logger


def qemu_img_type(path):
    qemu_img_info_command = ["qemu-img", "info", "--output", "json", path]
    try:
        qemu_img_info = sp.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 settings['storage']['storage_backend'] == 'filesystem' and not isdir(settings['storage']['image_dir']):
        sys.exit("You have set STORAGE_BACKEND to filesystem, but "
                 "{} does not exist. Refusing to start".format(settings['storage']['image_dir'])
        )

    try:
        sp.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 = shared.etcd_client.get_prefix(settings['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(settings['storage']['file_dir'], image_owner, image_filename)

            image_stores = shared.etcd_client.get_prefix(settings['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
                    sp.check_output(qemu_img_convert_command,)

                except sp.CalledProcessError:
                    logger.exception('Image convertion from .qcow2 to .raw failed.')
                else:
                    # Import and Protect
                    r_status = shared.storage_handler.import_image(src="image.raw",
                                                                   dest=image_uuid,
                                                                   protect=True)
                    if r_status:
                        # Everything is successfully done
                        image.value["status"] = "CREATED"
                        shared.etcd_client.put(image.key, json.dumps(image.value))
                finally:
                    try:
                        os.remove("image.raw")
                    except Exception:
                        pass

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


if __name__ == "__main__":
    main()