import os

import blivet
from blivet.size import Size
from blivet.util import set_up_logging, create_sparse_tempfile


set_up_logging()
b = blivet.Blivet()   # create an instance of Blivet (don't add system devices)

# create a disk image file on which to create new devices
disk1_file = create_sparse_tempfile("disk1", Size("100GiB"))
b.disk_images["disk1"] = disk1_file
disk2_file = create_sparse_tempfile("disk2", Size("100GiB"))
b.disk_images["disk2"] = disk2_file

b.reset()

try:
    disk1 = b.devicetree.get_device_by_name("disk1")
    disk2 = b.devicetree.get_device_by_name("disk2")

    b.initialize_disk(disk1)
    b.initialize_disk(disk2)

    pv = b.new_partition(size=Size("50GiB"), fmt_type="lvmpv", parents=[disk1])
    b.create_device(pv)
    pv2 = b.new_partition(size=Size("50GiB"), fmt_type="lvmpv", parents=[disk2])
    b.create_device(pv2)

    # allocate the partitions (decide where and on which disks they'll reside)
    blivet.partitioning.do_partitioning(b)

    vg = b.new_vg(parents=[pv, pv2])
    b.create_device(vg)

    # new lv with base size 5GiB and growth up to 15GiB and an ext4 filesystem
    lv = b.new_lv(fmt_type="ext4", size=Size("5GiB"), parents=[vg], name="cached")
    b.create_device(lv)

    # new cache pool
    cpool = b.new_lv(size=Size("1 GiB"), parents=[vg], pvs=[pv2], cache_pool=True, name="fastlv")
    b.create_device(cpool)

    # write the new partitions to disk and format them as specified
    b.do_it()
    print(b.devicetree)

    # attach the newly created cache pool to the "slow" LV
    lv.attach_cache(cpool)

    b.reset()
    print(b.devicetree)

    input("Check the state and hit ENTER to trigger cleanup")
finally:
    b.devicetree.teardown_disk_images()
    os.unlink(disk1_file)
    os.unlink(disk2_file)