from pathlib import Path
import subprocess
from tempfile import TemporaryDirectory

import pytest

from repo2docker.contentproviders import Mercurial
from repo2docker.contentproviders.mercurial import (
    HG_REQUIRED,
    HG_EVOLVE_REQUIRED,
    is_mercurial_available,
)

skip_if_no_hg = pytest.mark.skipif(
    not HG_REQUIRED and not is_mercurial_available(),
    reason="not HG_REQUIRED and Mercurial not available",
)


def is_evolve_available():
    if not is_mercurial_available():
        return False
    output = subprocess.getoutput("hg version -v")
    return " evolve " in output


EVOLVE_AVAILABLE = is_evolve_available()

if HG_EVOLVE_REQUIRED and not EVOLVE_AVAILABLE:
    raise RuntimeError("HG_EVOLVE_REQUIRED and not EVOLVE_AVAILABLE")


def _add_content_to_hg(repo_dir):
    """Add content to file 'test' in hg repository and commit."""
    # use append mode so this can be called multiple times
    with open(Path(repo_dir) / "test", "a") as f:
        f.write("Hello")

    subprocess.check_call(["hg", "add", "test"], cwd=repo_dir)
    subprocess.check_call(["hg", "commit", "-m", "Test commit"], cwd=repo_dir)

    if EVOLVE_AVAILABLE:
        subprocess.check_call(["hg", "topic", "test-topic"], cwd=repo_dir)
        subprocess.check_call(
            ["hg", "commit", "-m", "Test commit in topic test-topic"],
            cwd=repo_dir,
        )
        subprocess.check_call(["hg", "up", "default"], cwd=repo_dir)


def _get_node_id(repo_dir):
    """Get repository's current commit node ID (currently SHA1)."""
    node_id = subprocess.Popen(
        ["hg", "identify", "-i"], stdout=subprocess.PIPE, cwd=repo_dir
    )
    return node_id.stdout.read().decode().strip()


@pytest.fixture()
def hg_repo():
    """
    Make a dummy hg repo in which user can perform hg operations

    Should be used as a contextmanager, it will delete directory when done
    """
    with TemporaryDirectory() as hgdir:
        subprocess.check_call(["hg", "init"], cwd=hgdir)
        yield hgdir


@pytest.fixture()
def hg_repo_with_content(hg_repo):
    """Create a hg repository with content"""
    _add_content_to_hg(hg_repo)
    node_id = _get_node_id(hg_repo)

    yield hg_repo, node_id


@skip_if_no_hg
def test_detect_mercurial(hg_repo_with_content, repo_with_content):
    mercurial = Mercurial()
    assert mercurial.detect("this-is-not-a-directory") is None
    assert mercurial.detect("https://github.com/jupyterhub/repo2docker") is None

    git_repo = repo_with_content[0]
    assert mercurial.detect(git_repo) is None

    hg_repo = hg_repo_with_content[0]
    assert mercurial.detect(hg_repo) == {"repo": hg_repo, "ref": None}


@skip_if_no_hg
def test_clone(hg_repo_with_content):
    """Test simple hg clone to a target dir"""
    upstream, node_id = hg_repo_with_content

    with TemporaryDirectory() as clone_dir:
        spec = {"repo": upstream}
        mercurial = Mercurial()
        for _ in mercurial.fetch(spec, clone_dir):
            pass
        assert (Path(clone_dir) / "test").exists()

        assert mercurial.content_id == node_id


@skip_if_no_hg
def test_bad_ref(hg_repo_with_content):
    """
    Test trying to update to a ref that doesn't exist
    """
    upstream, node_id = hg_repo_with_content
    with TemporaryDirectory() as clone_dir:
        spec = {"repo": upstream, "ref": "does-not-exist"}
        with pytest.raises(ValueError):
            for _ in Mercurial().fetch(spec, clone_dir):
                pass


@pytest.mark.skipif(
    not HG_EVOLVE_REQUIRED and not EVOLVE_AVAILABLE,
    reason="not HG_EVOLVE_REQUIRED and hg-evolve not available",
)
@skip_if_no_hg
def test_ref_topic(hg_repo_with_content):
    """
    Test trying to update to a topic
    """
    upstream, node_id = hg_repo_with_content
    node_id = subprocess.Popen(
        ["hg", "identify", "-i", "-r", "topic(test-topic)"],
        stdout=subprocess.PIPE,
        cwd=upstream,
    )
    node_id = node_id.stdout.read().decode().strip()

    with TemporaryDirectory() as clone_dir:
        spec = {"repo": upstream, "ref": "test-topic"}
        mercurial = Mercurial()
        for _ in mercurial.fetch(spec, clone_dir):
            pass
        assert (Path(clone_dir) / "test").exists()

        assert mercurial.content_id == node_id