from __future__ import annotations

import typing

from typing import (

    Any,

    Collection,

    Iterable,

    Iterator,

    Set,

)

from mercurial.node import sha1nodeconstants

from mercurial.interfaces.types import MatcherT

from mercurial import (

    match as matchmod,

    pathutil,

    pycompat,

    util,

)

from mercurial.interfaces import (

    repository,

)

from . import gitutil

if typing.TYPE_CHECKING:

    from typing import (

        ByteString,  # TODO: change to Buffer for 3.14

    )

pygit2 = gitutil.get_pygit2()

class gittreemanifest(repository.imanifestdict):

    """Expose git trees (and optionally a builder's overlay) as a manifestdict.

    Very similar to mercurial.manifest.treemanifest.

    """

    def __init__(self, git_repo, root_tree, pending_changes):

        """Initializer.

        Args:

          git_repo: The git_repo we're walking (required to look up child

              trees).

          root_tree: The root Git tree object for this manifest.

          pending_changes: A dict in which pending changes will be

              tracked. The enclosing memgittreemanifestctx will use this to

              construct any required Tree objects in Git during it's

              `write()` method.

        """

        self._git_repo = git_repo

        self._tree = root_tree

        if pending_changes is None:

            pending_changes = {}

        # dict of path: Optional[Tuple(node, flags)]

        self._pending_changes = pending_changes

    def _resolve_entry(self, path) -> tuple[bytes, bytes]:

        """Given a path, load its node and flags, or raise KeyError if missing.

        This takes into account any pending writes in the builder.

        """

        upath = pycompat.fsdecode(path)

        ent = None

        if path in self._pending_changes:

            val = self._pending_changes[path]

            if val is None:

                raise KeyError

            return val

        t = self._tree

        comps = upath.split('/')

        te = self._tree

        for comp in comps[:-1]:

            te = te[comp]

            t = self._git_repo[te.id]

        ent = t[comps[-1]]

        if ent.filemode == pygit2.GIT_FILEMODE_BLOB:

            flags = b''

        elif ent.filemode == pygit2.GIT_FILEMODE_BLOB_EXECUTABLE:

            flags = b'x'

        elif ent.filemode == pygit2.GIT_FILEMODE_LINK:

            flags = b'l'

        else:

            raise ValueError('unsupported mode %s' % oct(ent.filemode))

        return ent.id.raw, flags

    def __getitem__(self, path: bytes) -> bytes:

        return self._resolve_entry(path)[0]

    def find(self, path: bytes) -> tuple[bytes, bytes]:

        return self._resolve_entry(path)

    def __len__(self) -> int:

        return len(list(self.walk(matchmod.always())))

    def __nonzero__(self) -> bool:

        try:

            next(iter(self))

            return True

        except StopIteration:

            return False

    __bool__ = __nonzero__

    def __contains__(self, path: bytes) -> bool:

        try:

            self._resolve_entry(path)

            return True

        except KeyError:

            return False

    def iterkeys(self) -> Iterator[bytes]:

        return self.walk(matchmod.always())

    def keys(self) -> list[bytes]:

        return list(self.iterkeys())

    def __iter__(self) -> Iterator[bytes]:

        return self.iterkeys()

    def set(self, path: bytes, node: bytes, flags: bytes) -> None:

        raise NotImplementedError  # TODO: implement this

    def __setitem__(self, path: bytes, node: bytes) -> None:

        self._pending_changes[path] = node, self.flags(path)

    def __delitem__(self, path: bytes) -> None:

        # TODO: should probably KeyError for already-deleted  files?

        self._pending_changes[path] = None

    def filesnotin(self, other, match=None) -> Set[bytes]:

        if match is not None:

            match = matchmod.badmatch(match, lambda path, msg: None)

            sm2 = set(other.walk(match))

            return {f for f in self.walk(match) if f not in sm2}

        return {f for f in self if f not in other}

    @util.propertycache

    def _dirs(self):

        return pathutil.dirs(self)

    def dirs(self) -> pathutil.dirs:

        return self._dirs  # TODO: why is there a prpoertycache?

    def hasdir(self, dir: bytes) -> bool:

        return dir in self._dirs

    def diff(

        self,

        other: Any,  # TODO: 'manifestdict' or (better) equivalent interface

        match: Any = lambda x: True,  # TODO: Optional[matchmod.basematcher] = None,

        clean: bool = False,

    ) -> dict[

        bytes,

        tuple[tuple[bytes | None, bytes], tuple[bytes | None, bytes]] | None,

    ]:

        """Finds changes between the current manifest and m2.

        The result is returned as a dict with filename as key and

        values of the form ((n1,fl1),(n2,fl2)), where n1/n2 is the

        nodeid in the current/other manifest and fl1/fl2 is the flag

        in the current/other manifest. Where the file does not exist,

        the nodeid will be None and the flags will be the empty

        string.

        """

        result = {}

        def _iterativediff(t1, t2, subdir):

            """compares two trees and appends new tree nodes to examine to

            the stack"""

            if t1 == t2:

                # If the trees are the same (git) object, then there are no

                # differences in this tree or any of its children.

                return

            if t1 is None:

                t1 = {}

            if t2 is None:

                t2 = {}

            for e1 in t1:

                realname = subdir + pycompat.fsencode(e1.name)

                if e1.type == pygit2.GIT_OBJ_TREE:

                    try:

                        e2 = t2[e1.name]

                        if e2.type != pygit2.GIT_OBJ_TREE:

                            e2 = None

                    except KeyError:

                        e2 = None

                    stack.append((realname + b'/', e1, e2))

                else:

                    n1, fl1 = self.find(realname)

                    try:

                        e2 = t2[e1.name]

                        n2, fl2 = other.find(realname)

                    except KeyError:

                        e2 = None

                        n2, fl2 = (None, b'')

                    if e2 is not None and e2.type == pygit2.GIT_OBJ_TREE:

                        stack.append((realname + b'/', None, e2))

                    if not match(realname):

                        continue

                    if n1 != n2 or fl1 != fl2:

                        result[realname] = ((n1, fl1), (n2, fl2))

                    elif clean:

                        result[realname] = None

            for e2 in t2:

                if e2.name in t1:

                    continue

                realname = subdir + pycompat.fsencode(e2.name)

                if e2.type == pygit2.GIT_OBJ_TREE:

                    stack.append((realname + b'/', None, e2))

                elif match(realname):

                    n2, fl2 = other.find(realname)

                    result[realname] = ((None, b''), (n2, fl2))

        stack = []

        _iterativediff(self._tree, other._tree, b'')

        while stack:

            subdir, t1, t2 = stack.pop()

            # stack is populated in the function call

            _iterativediff(t1, t2, subdir)

        return result

    def setflag(self, path: bytes, flag: bytes) -> None:

        node, unused_flag = self._resolve_entry(path)

        self._pending_changes[path] = node, flag

    def get(self, path: bytes, default=None) -> bytes | None:

        try:

            return self._resolve_entry(path)[0]

        except KeyError:

            return default

    def flags(self, path: bytes) -> bytes:

        try:

            return self._resolve_entry(path)[1]

        except KeyError:

            return b''

    def copy(self) -> gittreemanifest:

        return gittreemanifest(

            self._git_repo, self._tree, dict(self._pending_changes)

        )

    def items(self) -> Iterator[tuple[bytes, bytes]]:

        for f in self:

            # TODO: build a proper iterator version of this

            yield f, self[f]

    def iteritems(self) -> Iterator[tuple[bytes, bytes]]:

        return self.items()

    def iterentries(self) -> Iterator[tuple[bytes, bytes, bytes]]:

        for f in self:

            # TODO: build a proper iterator version of this

            yield f, *self._resolve_entry(f)

    def text(self) -> ByteString:

        # TODO can this method move out of the manifest iface?

        raise NotImplementedError

    def fastdelta(

        self, base: ByteString, changes: Iterable[tuple[bytes, bool]]

    ) -> tuple[ByteString, ByteString]:

        raise NotImplementedError  # TODO: implement this

    def _walkonetree(self, tree, match, subdir) -> Iterator[bytes]:

        for te in tree:

            # TODO: can we prune dir walks with the matcher?

            realname = subdir + pycompat.fsencode(te.name)

            if te.type == pygit2.GIT_OBJ_TREE:

                yield from self._walkonetree(

                    self._git_repo[te.id], match, realname + b'/'

                )

            elif match(realname):

                yield pycompat.fsencode(realname)

    def walk(self, match: MatcherT) -> Iterator[bytes]:

        # TODO: this is a very lazy way to merge in the pending

        # changes. There is absolutely room for optimization here by

        # being clever about walking over the sets...

        baseline = set(self._walkonetree(self._tree, match, b''))

        deleted = {p for p, v in self._pending_changes.items() if v is None}

        pend = {p for p in self._pending_changes if match(p)}

        return iter(sorted((baseline | pend) - deleted))

class gittreemanifestctx(repository.imanifestrevisionstored):

    def __init__(self, repo, gittree):

        self._repo = repo

        self._tree = gittree

    def read(self):

        return gittreemanifest(self._repo, self._tree, None)

    def readfast(self, shallow: bool = False):

        return self.read()

    def copy(self):

        # NB: it's important that we return a memgittreemanifestctx

        # because the caller expects a mutable manifest.

        return memgittreemanifestctx(self._repo, self._tree)

    def find(self, path: bytes) -> tuple[bytes, bytes]:

        return self.read().find(path)

    def node(self) -> bytes:

        raise NotImplementedError

    def readdelta(self, shallow: bool = False):

        raise NotImplementedError

    def read_any_fast_delta(

        self,

        valid_bases: Collection[int] | None = None,

        *,

        shallow: bool = False,

    ):

        raise NotImplementedError

    def read_delta_parents(self, *, shallow: bool = False, exact: bool = True):

        raise NotImplementedError

    def read_delta_new_entries(self, *, shallow: bool = False):

        raise NotImplementedError

    @property

    def parents(self):

        # FIXME: the 2 parent nodes

        return sha1nodeconstants.nullid, sha1nodeconstants.nullid

class memgittreemanifestctx(repository.imanifestrevisionwritable):

    def __init__(self, repo, tree):

        self._repo = repo

        self._tree = tree

        # dict of path: Optional[Tuple(node, flags)]

        self._pending_changes = {}

    def read(self):

        return gittreemanifest(self._repo, self._tree, self._pending_changes)

    def copy(self):

        # TODO: if we have a builder in play, what should happen here?

        # Maybe we can shuffle copy() into the immutable interface.

        return memgittreemanifestctx(self._repo, self._tree)

    def write(self, transaction, link, p1, p2, added, removed, match=None):

        # We're not (for now, anyway) going to audit filenames, so we

        # can ignore added and removed.

        # TODO what does this match argument get used for? hopefully

        # just narrow?

        assert not match or isinstance(match, matchmod.alwaysmatcher)

        touched_dirs = pathutil.dirs(list(self._pending_changes))

        trees = {

            b'': self._tree,

        }

        # path: treebuilder

        builders = {

            b'': self._repo.TreeBuilder(self._tree),

        }

        # get a TreeBuilder for every tree in the touched_dirs set

        for d in sorted(touched_dirs, key=lambda x: (len(x), x)):

            if d == b'':

                # loaded root tree above

                continue

            comps = d.split(b'/')

            full = b''

            for part in comps:

                parent = trees[full]

                try:

                    parent_tree_id = parent[pycompat.fsdecode(part)].id

                    new = self._repo[parent_tree_id]

                except KeyError:

                    # new directory

                    new = None

                full += b'/' + part

                if new is not None:

                    # existing directory

                    trees[full] = new

                    builders[full] = self._repo.TreeBuilder(new)

                else:

                    # new directory, use an empty dict to easily

                    # generate KeyError as any nested new dirs get

                    # created.

                    trees[full] = {}

                    builders[full] = self._repo.TreeBuilder()

        for f, info in self._pending_changes.items():

            if b'/' not in f:

                dirname = b''

                basename = f

            else:

                dirname, basename = f.rsplit(b'/', 1)

                dirname = b'/' + dirname

            if info is None:

                builders[dirname].remove(pycompat.fsdecode(basename))

            else:

                n, fl = info

                mode = {

                    b'': pygit2.GIT_FILEMODE_BLOB,

                    b'x': pygit2.GIT_FILEMODE_BLOB_EXECUTABLE,

                    b'l': pygit2.GIT_FILEMODE_LINK,

                }[fl]

                builders[dirname].insert(

                    pycompat.fsdecode(basename), gitutil.togitnode(n), mode

                )

        # This visits the buffered TreeBuilders in deepest-first

        # order, bubbling up the edits.

        for b in sorted(builders, key=len, reverse=True):

            if b == b'':

                break

            cb = builders[b]

            dn, bn = b.rsplit(b'/', 1)

            builders[dn].insert(

                pycompat.fsdecode(bn), cb.write(), pygit2.GIT_FILEMODE_TREE

            )

        return builders[b''].write().raw