# Copyright (C) 2018-2020  The Software Heritage developers
# See the AUTHORS file at the top-level directory of this distribution
# License: GNU General Public License version 3, or any later version
# See top-level LICENSE file for more information

import copy
import datetime
import os.path

import dulwich.repo
import pytest

from unittest import TestCase

from swh.model.model import Snapshot, SnapshotBranch, TargetType
from swh.model.hashutil import hash_to_bytes
from swh.loader.git.from_disk import GitLoaderFromDisk, GitLoaderFromArchive

from swh.loader.tests import (
    assert_last_visit_matches,
    check_snapshot,
    get_stats,
    prepare_repository_from_archive,
)


SNAPSHOT_ID = "a23699280a82a043f8c0994cf1631b568f716f95"

SNAPSHOT1 = {
    "id": SNAPSHOT_ID,
    "branches": {
        "HEAD": {"target": "refs/heads/master", "target_type": "alias",},
        "refs/heads/master": {
            "target": "2f01f5ca7e391a2f08905990277faf81e709a649",
            "target_type": "revision",
        },
        "refs/heads/branch1": {
            "target": "b0a77609903f767a2fd3d769904ef9ef68468b87",
            "target_type": "revision",
        },
        "refs/heads/branch2": {
            "target": "bd746cd1913721b269b395a56a97baf6755151c2",
            "target_type": "revision",
        },
        "refs/tags/branch2-after-delete": {
            "target": "bd746cd1913721b269b395a56a97baf6755151c2",
            "target_type": "revision",
        },
        "refs/tags/branch2-before-delete": {
            "target": "1135e94ccf73b5f9bd6ef07b3fa2c5cc60bba69b",
            "target_type": "revision",
        },
    },
}

# directory hashes obtained with:
# gco b6f40292c4e94a8f7e7b4aff50e6c7429ab98e2a
# swh-hashtree --ignore '.git' --path .
# gco 2f01f5ca7e391a2f08905990277faf81e709a649
# swh-hashtree --ignore '.git' --path .
# gco bcdc5ebfde1a3cd6c96e0c2ea4eed19c13208777
# swh-hashtree --ignore '.git' --path .
# gco 1135e94ccf73b5f9bd6ef07b3fa2c5cc60bba69b
# swh-hashtree --ignore '.git' --path .
# gco 79f65ac75f79dda6ff03d66e1242702ab67fb51c
# swh-hashtree --ignore '.git' --path .
# gco b0a77609903f767a2fd3d769904ef9ef68468b87
# swh-hashtree --ignore '.git' --path .
# gco bd746cd1913721b269b395a56a97baf6755151c2
# swh-hashtree --ignore '.git' --path .
REVISIONS1 = {
    "b6f40292c4e94a8f7e7b4aff50e6c7429ab98e2a": (
        "40dbdf55dfd4065422462cc74a949254aefa972e"
    ),
    "2f01f5ca7e391a2f08905990277faf81e709a649": (
        "e1d0d894835f91a0f887a4bc8b16f81feefdfbd5"
    ),
    "bcdc5ebfde1a3cd6c96e0c2ea4eed19c13208777": (
        "b43724545b4759244bb54be053c690649161411c"
    ),
    "1135e94ccf73b5f9bd6ef07b3fa2c5cc60bba69b": (
        "fbf70528223d263661b5ad4b80f26caf3860eb8e"
    ),
    "79f65ac75f79dda6ff03d66e1242702ab67fb51c": (
        "5df34ec74d6f69072d9a0a6677d8efbed9b12e60"
    ),
    "b0a77609903f767a2fd3d769904ef9ef68468b87": (
        "9ca0c7d6ffa3f9f0de59fd7912e08f11308a1338"
    ),
    "bd746cd1913721b269b395a56a97baf6755151c2": (
        "e1d0d894835f91a0f887a4bc8b16f81feefdfbd5"
    ),
}


class CommonGitLoaderTests:
    """Common tests for all git loaders."""

    def test_load(self):
        """Loads a simple repository (made available by `setUp()`),
        and checks everything was added in the storage."""
        res = self.loader.load()

        assert res == {"status": "eventful"}

        assert_last_visit_matches(
            self.loader.storage,
            self.repo_url,
            status="full",
            type="git",
            snapshot=hash_to_bytes(SNAPSHOT1["id"]),
        )

        stats = get_stats(self.loader.storage)
        assert stats == {
            "content": 4,
            "directory": 7,
            "origin": 1,
            "origin_visit": 1,
            "person": 1,
            "release": 0,
            "revision": 7,
            "skipped_content": 0,
            "snapshot": 1,
        }

        check_snapshot(SNAPSHOT1, self.loader.storage)

    def test_load_unchanged(self):
        """Checks loading a repository a second time does not add
        any extra data."""
        res = self.loader.load()
        assert res == {"status": "eventful"}

        assert_last_visit_matches(
            self.loader.storage,
            self.repo_url,
            status="full",
            type="git",
            snapshot=hash_to_bytes(SNAPSHOT1["id"]),
        )

        stats0 = get_stats(self.loader.storage)
        assert stats0 == {
            "content": 4,
            "directory": 7,
            "origin": 1,
            "origin_visit": 1,
            "person": 1,
            "release": 0,
            "revision": 7,
            "skipped_content": 0,
            "snapshot": 1,
        }

        res = self.loader.load()
        assert res == {"status": "uneventful"}
        stats1 = get_stats(self.loader.storage)
        expected_stats = copy.deepcopy(stats0)
        expected_stats["origin_visit"] += 1
        assert stats1 == expected_stats

        check_snapshot(SNAPSHOT1, self.loader.storage)

        assert_last_visit_matches(
            self.loader.storage,
            self.repo_url,
            status="full",
            type="git",
            snapshot=hash_to_bytes(SNAPSHOT1["id"]),
        )


class FullGitLoaderTests(CommonGitLoaderTests):
    """Tests for GitLoader (from disk or not). Includes the common ones, and
       add others that only work with a local dir.

    """

    def test_load_changed(self):
        """Loads a repository, makes some changes by adding files, commits,
        and merges, load it again, and check the storage contains everything
        it should."""
        # Initial load
        res = self.loader.load()
        assert res == {"status": "eventful"}

        stats0 = get_stats(self.loader.storage)
        assert stats0 == {
            "content": 4,
            "directory": 7,
            "origin": 1,
            "origin_visit": 1,
            "person": 1,
            "release": 0,
            "revision": 7,
            "skipped_content": 0,
            "snapshot": 1,
        }

        # Load with a new file + revision
        with open(os.path.join(self.destination_path, "hello.py"), "a") as fd:
            fd.write("print('Hello world')\n")

        self.repo.stage([b"hello.py"])
        new_revision = self.repo.do_commit(b"Hello world\n").decode()
        new_dir = "85dae072a5aa9923ffa7a7568f819ff21bf49858"

        assert self.repo[new_revision.encode()].tree == new_dir.encode()

        revisions = REVISIONS1.copy()
        assert new_revision not in revisions
        revisions[new_revision] = new_dir

        res = self.loader.load()
        assert res == {"status": "eventful"}

        stats1 = get_stats(self.loader.storage)
        expected_stats = copy.deepcopy(stats0)
        # did one new visit
        expected_stats["origin_visit"] += 1
        # with one more of the following objects
        expected_stats["person"] += 1
        expected_stats["content"] += 1
        expected_stats["directory"] += 1
        expected_stats["revision"] += 1
        # concluding into 1 new snapshot
        expected_stats["snapshot"] += 1

        assert stats1 == expected_stats

        visit_status = assert_last_visit_matches(
            self.loader.storage, self.repo_url, status="full", type="git"
        )
        assert visit_status.snapshot is not None

        snapshot_id = visit_status.snapshot
        snapshot = self.loader.storage.snapshot_get(snapshot_id)
        branches = snapshot["branches"]
        assert branches[b"HEAD"] == {
            "target": b"refs/heads/master",
            "target_type": "alias",
        }
        assert branches[b"refs/heads/master"] == {
            "target": hash_to_bytes(new_revision),
            "target_type": "revision",
        }

        # Merge branch1 into HEAD.

        current = self.repo[b"HEAD"]
        branch1 = self.repo[b"refs/heads/branch1"]

        merged_tree = dulwich.objects.Tree()
        for item in self.repo[current.tree].items():
            merged_tree.add(*item)
        for item in self.repo[branch1.tree].items():
            merged_tree.add(*item)

        merged_dir_id = "dab8a37df8db8666d4e277bef9a546f585b5bedd"
        assert merged_tree.id.decode() == merged_dir_id
        self.repo.object_store.add_object(merged_tree)

        merge_commit = self.repo.do_commit(
            b"merge.\n", tree=merged_tree.id, merge_heads=[branch1.id]
        )

        assert merge_commit.decode() not in revisions
        revisions[merge_commit.decode()] = merged_tree.id.decode()

        res = self.loader.load()
        assert res == {"status": "eventful"}

        stats2 = get_stats(self.loader.storage)
        expected_stats = copy.deepcopy(stats1)
        # one more visit
        expected_stats["origin_visit"] += 1
        # with 1 new directory and revision
        expected_stats["directory"] += 1
        expected_stats["revision"] += 1
        # concluding into 1 new snapshot
        expected_stats["snapshot"] += 1

        assert stats2 == expected_stats

        visit_status = assert_last_visit_matches(
            self.loader.storage, self.repo_url, status="full", type="git"
        )
        assert visit_status.snapshot is not None

        merge_snapshot_id = visit_status.snapshot
        assert merge_snapshot_id != snapshot_id

        merge_snapshot = self.loader.storage.snapshot_get(merge_snapshot_id)
        merge_branches = merge_snapshot["branches"]
        assert merge_branches[b"HEAD"] == {
            "target": b"refs/heads/master",
            "target_type": "alias",
        }
        assert merge_branches[b"refs/heads/master"] == {
            "target": hash_to_bytes(merge_commit.decode()),
            "target_type": "revision",
        }

    def test_load_filter_branches(self):
        filtered_branches = {b"refs/pull/42/merge"}
        unfiltered_branches = {b"refs/pull/42/head"}

        # Add branches to the repository on disk; some should be filtered by
        # the loader, some should not.
        for branch_name in filtered_branches | unfiltered_branches:
            self.repo[branch_name] = self.repo[b"refs/heads/master"]

        # Generate the expected snapshot from SNAPSHOT1 (which is the original
        # state of the git repo)...
        branches = {}

        for branch_name, branch_dict in SNAPSHOT1["branches"].items():
            target_type_name = branch_dict["target_type"]
            target_obj = branch_dict["target"]

            if target_type_name != "alias":
                target = bytes.fromhex(target_obj)
            else:
                target = target_obj.encode()

            branch = SnapshotBranch(
                target=target, target_type=TargetType(target_type_name)
            )
            branches[branch_name.encode()] = branch

        # ... and the unfiltered_branches, which are all pointing to the same
        # commit as "refs/heads/master".
        for branch_name in unfiltered_branches:
            branches[branch_name] = branches[b"refs/heads/master"]

        expected_snapshot = Snapshot(branches=branches)

        # Load the modified repository
        res = self.loader.load()
        assert res == {"status": "eventful"}

        assert_last_visit_matches(
            self.loader.storage,
            self.repo_url,
            status="full",
            type="git",
            snapshot=expected_snapshot.id,
        )

    def test_load_dangling_symref(self):
        with open(os.path.join(self.destination_path, ".git/HEAD"), "wb") as f:
            f.write(b"ref: refs/heads/dangling-branch\n")

        res = self.loader.load()
        assert res == {"status": "eventful"}

        visit_status = assert_last_visit_matches(
            self.loader.storage, self.repo_url, status="full", type="git"
        )
        snapshot_id = visit_status.snapshot
        assert snapshot_id is not None

        snapshot = self.loader.storage.snapshot_get(snapshot_id)
        branches = snapshot["branches"]

        assert branches[b"HEAD"] == {
            "target": b"refs/heads/dangling-branch",
            "target_type": "alias",
        }
        assert branches[b"refs/heads/dangling-branch"] is None

        stats = get_stats(self.loader.storage)
        assert stats == {
            "content": 4,
            "directory": 7,
            "origin": 1,
            "origin_visit": 1,
            "person": 1,
            "release": 0,
            "revision": 7,
            "skipped_content": 0,
            "snapshot": 1,
        }


class GitLoaderFromDiskTest(TestCase, FullGitLoaderTests):
    """Prepare a git directory repository to be loaded through a GitLoaderFromDisk.
    This tests all git loader scenario.

    """

    @pytest.fixture(autouse=True)
    def init(self, swh_config, datadir, tmp_path):
        archive_name = "testrepo"
        archive_path = os.path.join(datadir, f"{archive_name}.tgz")
        tmp_path = str(tmp_path)
        self.repo_url = prepare_repository_from_archive(
            archive_path, archive_name, tmp_path=tmp_path
        )
        self.destination_path = os.path.join(tmp_path, archive_name)
        self.loader = GitLoaderFromDisk(
            url=self.repo_url,
            visit_date=datetime.datetime(
                2016, 5, 3, 15, 16, 32, tzinfo=datetime.timezone.utc
            ),
            directory=self.destination_path,
        )
        self.repo = dulwich.repo.Repo(self.destination_path)


class GitLoaderFromArchiveTest(TestCase, CommonGitLoaderTests):
    """Tests for GitLoaderFromArchive. Only tests common scenario."""

    @pytest.fixture(autouse=True)
    def init(self, swh_config, datadir, tmp_path):
        archive_name = "testrepo"
        archive_path = os.path.join(datadir, f"{archive_name}.tgz")
        self.repo_url = archive_path
        self.loader = GitLoaderFromArchive(
            url=self.repo_url,
            archive_path=archive_path,
            visit_date=datetime.datetime(
                2016, 5, 3, 15, 16, 32, tzinfo=datetime.timezone.utc
            ),
        )