import os
import pytest

from buildstream import _yaml
from buildstream._artifactcache import CACHE_SIZE_FILE

from tests.testutils import cli, create_element_size

# XXX: Currently lacking:
#      * A way to check whether it's faster to read cache size on
#        successive invocations.
#      * A way to check whether the cache size file has been read.


def create_project(project_dir):
    project_file = os.path.join(project_dir, "project.conf")
    project_conf = {
        "name": "test"
    }
    _yaml.dump(project_conf, project_file)
    element_name = "test.bst"
    create_element_size(element_name, project_dir, ".", [], 1024)


def test_cache_size_roundtrip(cli, tmpdir):
    # Builds (to put files in the cache), then invokes buildstream again
    # to check nothing breaks

    # Create project
    project_dir = str(tmpdir)
    create_project(project_dir)

    # Build, to populate the cache
    res = cli.run(project=project_dir, args=["build", "test.bst"])
    res.assert_success()

    # Show, to check that nothing breaks while reading cache size
    res = cli.run(project=project_dir, args=["show", "test.bst"])
    res.assert_success()


def test_cache_size_write(cli, tmpdir):
    # Builds (to put files in the cache), then checks a number is
    # written to the cache size file.

    project_dir = str(tmpdir)
    create_project(project_dir)

    # Artifact cache must be in a known place
    artifactdir = os.path.join(project_dir, "artifacts")
    cli.configure({"artifactdir": artifactdir})

    # Build, to populate the cache
    res = cli.run(project=project_dir, args=["build", "test.bst"])
    res.assert_success()

    # Inspect the artifact cache
    sizefile = os.path.join(artifactdir, CACHE_SIZE_FILE)
    assert os.path.isfile(sizefile)
    with open(sizefile, "r") as f:
        size_data = f.read()
    size = int(size_data)