# Source code for renku.core.management.git

    # -*- coding: utf-8 -*-
    #
    # Copyright 2018-2021 - Swiss Data Science Center (SDSC)
    # A partnership between École Polytechnique Fédérale de Lausanne (EPFL) and
    # Eidgenössische Technische Hochschule Zürich (ETHZ).
    #
    # Licensed under the Apache License, Version 2.0 (the "License");
    # you may not use this file except in compliance with the License.
    # You may obtain a copy of the License at
    #
    #     http://www.apache.org/licenses/LICENSE-2.0
    #
    # Unless required by applicable law or agreed to in writing, software
    # distributed under the License is distributed on an "AS IS" BASIS,
    # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    # See the License for the specific language governing permissions and
    # limitations under the License.
    """Wrap Git client."""

    import glob
    import itertools
    import os
    import sys
    import tempfile
    import time
    import uuid
    from collections import defaultdict
    from contextlib import contextmanager
    from itertools import zip_longest
    from pathlib import Path

    import attr
    import git

    from renku.core import errors
    from renku.core.utils.git import split_paths
    from renku.core.utils.scm import git_unicode_unescape, shorten_message
    from renku.core.utils.urls import remove_credentials

    COMMIT_DIFF_STRATEGY = "DIFF"
    STARTED_AT = int(time.time() * 1e3)

    def prepare_commit(
        client,
        commit_only=None,
        skip_dirty_checks=False,
    ):
        """Gather information about repo needed for committing later on."""
        diff_before = set()

        if commit_only == COMMIT_DIFF_STRATEGY:
            staged = {git_unicode_unescape(item.a_path) for item in client.repo.index.diff(None)}

            modified = {git_unicode_unescape(item.a_path) for item in client.repo.index.diff("HEAD")}

            if staged or modified:
                client.repo.git.reset()

            # Exclude files created by pipes.
            diff_before = {
                file_ for file_ in client.repo.untracked_files if STARTED_AT - int(Path(file_).stat().st_ctime * 1e3) >= 1e3
            }

        if isinstance(commit_only, list) and not skip_dirty_checks:
            for path_ in commit_only:
                client.ensure_untracked(str(path_))
                client.ensure_unstaged(str(path_))

        project_metadata_path = str(client.renku_metadata_path)

        return project_metadata_path, diff_before

    def finalize_commit(
        client,
        project_metadata_path,
        diff_before,
        commit_only=None,
        commit_empty=True,
        raise_if_empty=False,
        commit_message=None,
        abbreviate_message=True,
    ):
        """Commit modified/added paths."""
        from git import Actor

        from renku.version import __version__, version_url

        committer = Actor("renku {0}".format(__version__), version_url)

        change_types = {git_unicode_unescape(item.a_path): item.change_type for item in client.repo.index.diff(None)}

        if commit_only == COMMIT_DIFF_STRATEGY:
            # Get diff generated in command.
            staged_after = set(change_types.keys())

            modified_after_change_types = {
                git_unicode_unescape(item.a_path): item.change_type for item in client.repo.index.diff("HEAD")
            }

            modified_after = set(modified_after_change_types.keys())

            change_types.update(modified_after_change_types)

            diff_after = set(client.repo.untracked_files).union(staged_after).union(modified_after)

            # Remove files not touched in command.
            commit_only = list(diff_after - diff_before)

        if isinstance(commit_only, list):
            for path_ in commit_only:
                p = client.path / path_
                if p.exists() or change_types.get(str(path_)) == "D":
                    client.repo.git.add(path_)

        if not commit_only:
            client.repo.git.add("--all")

        diffs = []
        try:
            diffs = [git_unicode_unescape(d.a_path) for d in client.repo.index.diff("HEAD")]
            if project_metadata_path in diffs:
                diffs.remove(project_metadata_path)
        except git.exc.BadName:
            pass

        if not commit_empty and not diffs:
            if raise_if_empty:
                raise errors.NothingToCommit()
            return

        if commit_message and not isinstance(commit_message, str):
            raise errors.CommitMessageEmpty()

        elif not commit_message:
            argv = [os.path.basename(sys.argv[0])] + [remove_credentials(arg) for arg in sys.argv[1:]]

            commit_message = " ".join(argv)

        if abbreviate_message:
            commit_message = shorten_message(commit_message)

        try:
            project = client.project
            if project:
                project.to_yaml()
                client.repo.index.add(project_metadata_path)
        except ValueError:
            pass

        # Ignore pre-commit hooks since we have already done everything.
        client.repo.index.commit(commit_message, committer=committer, skip_hooks=True)

    def get_mapped_std_streams(lookup_paths, streams=("stdin", "stdout", "stderr")):
        """Get a mapping of standard streams to given paths."""
        # FIXME add device number too
        standard_inos = {}
        for stream in streams:
            try:
                stream_stat = os.fstat(getattr(sys, stream).fileno())
                key = stream_stat.st_dev, stream_stat.st_ino
                standard_inos[key] = stream
            except Exception:  # FIXME UnsupportedOperation
                pass
            # FIXME if not getattr(sys, stream).istty()

        def stream_inos(paths):
            """Yield tuples with stats and path."""
            for path in paths:
                try:
                    stat = os.stat(path)
                    key = (stat.st_dev, stat.st_ino)
                    if key in standard_inos:
                        yield standard_inos[key], path
                except FileNotFoundError:  # pragma: no cover
                    pass

            return []

        return dict(stream_inos(lookup_paths)) if standard_inos else {}

    def _clean_streams(repo, mapped_streams):
        """Clean mapped standard streams."""
        for stream_name in ("stdout", "stderr"):
            stream = mapped_streams.get(stream_name)
            if not stream:
                continue

            path = os.path.relpath(stream, start=repo.working_dir)
            if (path, 0) not in repo.index.entries:
                os.remove(stream)
            else:
                blob = repo.index.entries[(path, 0)].to_blob(repo)
                with open(path, "wb") as fp:
                    fp.write(blob.data_stream.read())

    def _expand_directories(paths):
        """Expand directory with all files it contains."""
        processed_paths = set()
        for path in paths:
            for matched_path in glob.iglob(str(path), recursive=True):
                if matched_path in processed_paths:
                    continue
                path_ = Path(matched_path)
                if path_.is_dir():
                    for expanded in path_.rglob("*"):
                        processed_paths.add(str(expanded))
                        yield str(expanded)
                else:
                    processed_paths.add(matched_path)
                    yield matched_path

    @attr.s
    class GitCore:
        """Wrap Git client."""

        repo = attr.ib(init=False)
        """Store an instance of the Git repository."""

        def __attrs_post_init__(self):
            """Initialize computed attributes."""
            from git import InvalidGitRepositoryError, Repo

            #: Create an instance of a Git repository for the given path.
            try:
                self.repo = Repo(str(self.path))
            except InvalidGitRepositoryError:
                self.repo = None

        @property
        def modified_paths(self):
            """Return paths of modified files."""
            return [item.b_path for item in self.repo.index.diff(None) if item.b_path]

        @property
        def dirty_paths(self):
            """Get paths of dirty files in the repository."""
            repo_path = self.repo.working_dir
            staged_files = (
                [git_unicode_unescape(d.a_path) for d in self.repo.index.diff("HEAD")] if self.repo.head.is_valid() else []
            )
            return {os.path.join(repo_path, p) for p in self.repo.untracked_files + self.modified_paths + staged_files}

        @property
        def candidate_paths(self):
            """Return all paths in the index and untracked files."""
            repo_path = self.repo.working_dir
            return [
                os.path.join(repo_path, path)
                for path in itertools.chain((x[0] for x in self.repo.index.entries), self.repo.untracked_files)
            ]

        def find_ignored_paths(self, *paths):
            """Return ignored paths matching ``.gitignore`` file."""
            from git.exc import GitCommandError

            ignored = []
            for batch in split_paths(*paths):
                try:
                    ignored.extend(self.repo.git.check_ignore(*batch).split(os.linesep))
                except GitCommandError:
                    pass

            return ignored

        def find_attr(self, *paths):
            """Return map with path and its attributes."""
            from git.exc import GitCommandError

            attrs = defaultdict(dict)

            for batch in split_paths(*paths):
                try:
                    data = self.repo.git.check_attr("-z", "-a", "--", *batch)
                    for file, name, value in zip_longest(*[iter(data.strip("\0").split("\0"))] * 3):
                        if file:
                            attrs[file][name] = value
                except GitCommandError:
                    pass

            return attrs

        def remove_unmodified(self, paths, autocommit=True):
            """Remove unmodified paths and return their names."""
            tested_paths = set(_expand_directories(paths))

            # Keep only unchanged files in the output paths.
            tracked_paths = {
                diff.b_path
                for diff in self.repo.index.diff(None)
                if diff.change_type in {"A", "R", "M", "T"} and diff.b_path in tested_paths
            }
            unchanged_paths = tested_paths - tracked_paths

            # Fix tracking of unchanged files by removing them first.
            if autocommit and unchanged_paths:
                self.repo.index.remove(unchanged_paths, cached=True, r=True, ignore_unmatch=True)
                self.repo.index.commit("renku: automatic removal of unchanged files")
                self.repo.index.add(unchanged_paths)

            return unchanged_paths

        def ensure_clean(self, ignore_std_streams=False):
            """Make sure the repository is clean."""
            dirty_paths = self.dirty_paths
            mapped_streams = get_mapped_std_streams(dirty_paths)

            if ignore_std_streams:
                if dirty_paths - set(mapped_streams.values()):
                    _clean_streams(self.repo, mapped_streams)
                    raise errors.DirtyRepository(self.repo)

            elif self.repo.is_dirty(untracked_files=True):
                _clean_streams(self.repo, mapped_streams)
                raise errors.DirtyRepository(self.repo)

        def ensure_untracked(self, path):
            """Ensure that path is not part of git untracked files."""
            untracked = self.repo.untracked_files

            for file_path in untracked:
                is_parent = (self.path / file_path).parent == (self.path / path)
                is_equal = path == file_path

                if is_parent or is_equal:
                    raise errors.DirtyRenkuDirectory(self.repo)

        def ensure_unstaged(self, path):
            """Ensure that path is not part of git staged files."""
            try:
                staged = self.repo.index.diff("HEAD")

                for file_path in staged:
                    unescaped_path = git_unicode_unescape(file_path.a_path)
                    is_parent = str(unescaped_path).startswith(path)
                    is_equal = path == unescaped_path

                    if is_parent or is_equal:
                        raise errors.DirtyRenkuDirectory(self.repo)

            except git.exc.BadName:
                pass

        def setup_credential_helper(self):
            """Setup git credential helper to ``cache`` if not set already."""
            credential_helper = self.repo.config_reader().get_value("credential", "helper", "")

            if not credential_helper:
                with self.repo.config_writer() as w:
                    w.set_value("credential", "helper", "cache")

        @contextmanager
        def commit(
            self,
            commit_only=None,
            commit_empty=True,
            raise_if_empty=False,
            commit_message=None,
            abbreviate_message=True,
            skip_dirty_checks=False,
        ):
            """Automatic commit."""

            project_metadata_path, diff_before = prepare_commit(
                self, commit_only=commit_only, skip_dirty_checks=skip_dirty_checks
            )

            yield

            finalize_commit(
                self,
                project_metadata_path,
                diff_before,
                commit_only=commit_only,
                commit_empty=commit_empty,
                raise_if_empty=raise_if_empty,
                commit_message=commit_message,
                abbreviate_message=abbreviate_message,
            )

        @contextmanager
        def worktree(self, path=None, branch_name=None, commit=None, merge_args=("--ff-only",)):
            """Create new worktree."""
            from git import NULL_TREE, GitCommandError

            from renku.core.utils.contexts import Isolation

            delete = path is None
            path = path or tempfile.mkdtemp()
            branch_name = branch_name or "renku/run/isolation/" + uuid.uuid4().hex

            # TODO sys.argv

            new_branch = False

            if commit is NULL_TREE:
                args = ["add", "--detach", path]
                self.repo.git.worktree(*args)
                client = attr.evolve(self, path=path)
                client.repo.git.checkout("--orphan", branch_name)
                client.repo.git.rm("-rf", "*")
            else:
                args = ["add", "-b", branch_name, path]
                if commit:
                    args.append(commit)
                self.repo.git.worktree(*args)
                client = attr.evolve(self, path=path)
                new_branch = True

            client.repo.config_reader = self.repo.config_reader

            # Keep current directory relative to repository root.
            relative = Path(os.path.relpath(Path(".").resolve(), self.path))

            # Reroute standard streams
            original_mapped_std = get_mapped_std_streams(self.candidate_paths)
            mapped_std = {}
            for name, stream in original_mapped_std.items():
                stream_path = Path(path) / (Path(stream).relative_to(self.path))
                stream_path = stream_path.absolute()

                if not stream_path.exists():
                    stream_path.parent.mkdir(parents=True, exist_ok=True)
                    stream_path.touch()

                mapped_std[name] = stream_path

            _clean_streams(self.repo, original_mapped_std)

            new_cwd = Path(path) / relative
            new_cwd.mkdir(parents=True, exist_ok=True)

            with Isolation(cwd=str(new_cwd), **mapped_std):
                yield client

            try:
                self.repo.git.merge(branch_name, *merge_args)
            except GitCommandError:
                raise errors.FailedMerge(self.repo, branch_name, merge_args)

            if delete:
                self.repo.git.worktree("remove", path)

                if new_branch:
                    # delete the created temporary branch
                    self.repo.git.branch("-d", branch_name)
            if self.external_storage_requested:
                self.checkout_paths_from_storage()