from __future__ import absolute_import

import pygit2

from mercurial.i18n import _

from mercurial import (
    ancestor,
    changelog as hgchangelog,
    dagop,
    encoding,
    error,
    manifest,
    node as nodemod,
    pycompat,
)
from mercurial.interfaces import (
    repository,
    util as interfaceutil,
)
from mercurial.utils import stringutil
from . import (
    gitutil,
    index,
    manifest as gitmanifest,
)


class baselog(object):  # revlog.revlog):
    """Common implementations between changelog and manifestlog."""

    def __init__(self, gr, db):
        self.gitrepo = gr
        self._db = db

    def __len__(self):
        return int(
            self._db.execute('SELECT COUNT(*) FROM changelog').fetchone()[0]
        )

    def rev(self, n):
        if n == nodemod.nullid:
            return -1
        t = self._db.execute(
            'SELECT rev FROM changelog WHERE node = ?', (gitutil.togitnode(n),)
        ).fetchone()
        if t is None:
            raise error.LookupError(n, b'00changelog.i', _(b'no node %d'))
        return t[0]

    def node(self, r):
        if r == nodemod.nullrev:
            return nodemod.nullid
        t = self._db.execute(
            'SELECT node FROM changelog WHERE rev = ?', (r,)
        ).fetchone()
        if t is None:
            raise error.LookupError(r, b'00changelog.i', _(b'no node'))
        return nodemod.bin(t[0])

    def hasnode(self, n):
        t = self._db.execute(
            'SELECT node FROM changelog WHERE node = ?', (n,)
        ).fetchone()
        return t is not None


class baselogindex(object):
    def __init__(self, log):
        self._log = log

    def has_node(self, n):
        return self._log.rev(n) != -1

    def __len__(self):
        return len(self._log)

    def __getitem__(self, idx):
        p1rev, p2rev = self._log.parentrevs(idx)
        # TODO: it's messy that the index leaks so far out of the
        # storage layer that we have to implement things like reading
        # this raw tuple, which exposes revlog internals.
        return (
            # Pretend offset is just the index, since we don't really care.
            idx,
            # Same with lengths
            idx,  # length
            idx,  # rawsize
            -1,  # delta base
            idx,  # linkrev TODO is this right?
            p1rev,
            p2rev,
            self._log.node(idx),
        )


# TODO: an interface for the changelog type?
class changelog(baselog):
    def __contains__(self, rev):
        try:
            self.node(rev)
            return True
        except error.LookupError:
            return False

    @property
    def filteredrevs(self):
        # TODO: we should probably add a refs/hg/ namespace for hidden
        # heads etc, but that's an idea for later.
        return set()

    @property
    def index(self):
        return baselogindex(self)

    @property
    def nodemap(self):
        r = {
            nodemod.bin(v[0]): v[1]
            for v in self._db.execute('SELECT node, rev FROM changelog')
        }
        r[nodemod.nullid] = nodemod.nullrev
        return r

    def tip(self):
        t = self._db.execute(
            'SELECT node FROM changelog ORDER BY rev DESC LIMIT 1'
        ).fetchone()
        if t:
            return nodemod.bin(t[0])
        return nodemod.nullid

    def revs(self, start=0, stop=None):
        if stop is None:
            stop = self.tip()
        t = self._db.execute(
            'SELECT rev FROM changelog '
            'WHERE rev >= ? AND rev <= ? '
            'ORDER BY REV ASC',
            (start, stop),
        )
        return (int(r[0]) for r in t)

    def _partialmatch(self, id):
        if nodemod.wdirhex.startswith(id):
            raise error.WdirUnsupported
        candidates = [
            nodemod.bin(x[0])
            for x in self._db.execute(
                'SELECT node FROM changelog WHERE node LIKE ?', (id + b'%',)
            )
        ]
        if nodemod.nullhex.startswith(id):
            candidates.append(nodemod.nullid)
        if len(candidates) > 1:
            raise error.AmbiguousPrefixLookupError(
                id, b'00changelog.i', _(b'ambiguous identifier')
            )
        if candidates:
            return candidates[0]
        return None

    def flags(self, rev):
        return 0

    def shortest(self, node, minlength=1):
        nodehex = nodemod.hex(node)
        for attempt in pycompat.xrange(minlength, len(nodehex) + 1):
            candidate = nodehex[:attempt]
            matches = int(
                self._db.execute(
                    'SELECT COUNT(*) FROM changelog WHERE node LIKE ?',
                    (pycompat.sysstr(nodehex + b'%'),),
                ).fetchone()[0]
            )
            if matches == 1:
                return candidate
        return nodehex

    def headrevs(self, revs=None):
        realheads = [
            int(x[0])
            for x in self._db.execute(
                'SELECT rev FROM changelog '
                'INNER JOIN heads ON changelog.node = heads.node'
            )
        ]
        if revs:
            return sorted([r for r in revs if r in realheads])
        return sorted(realheads)

    def changelogrevision(self, nodeorrev):
        # Ensure we have a node id
        if isinstance(nodeorrev, int):
            n = self.node(nodeorrev)
        else:
            n = nodeorrev
        # handle looking up nullid
        if n == nodemod.nullid:
            return hgchangelog._changelogrevision(extra={})
        hn = gitutil.togitnode(n)
        # We've got a real commit!
        files = [
            r[0]
            for r in self._db.execute(
                'SELECT filename FROM changedfiles '
                'WHERE node = ? and filenode != ?',
                (hn, gitutil.nullgit),
            )
        ]
        filesremoved = [
            r[0]
            for r in self._db.execute(
                'SELECT filename FROM changedfiles '
                'WHERE node = ? and filenode = ?',
                (hn, nodemod.nullhex),
            )
        ]
        c = self.gitrepo[hn]
        return hgchangelog._changelogrevision(
            manifest=n,  # pretend manifest the same as the commit node
            user=b'%s <%s>'
            % (c.author.name.encode('utf8'), c.author.email.encode('utf8')),
            date=(c.author.time, -c.author.offset * 60),
            files=files,
            # TODO filesadded in the index
            filesremoved=filesremoved,
            description=c.message.encode('utf8'),
            # TODO do we want to handle extra? how?
            extra={b'branch': b'default'},
        )

    def ancestors(self, revs, stoprev=0, inclusive=False):
        revs = list(revs)
        tip = self.rev(self.tip())
        for r in revs:
            if r > tip:
                raise IndexError(b'Invalid rev %r' % r)
        return ancestor.lazyancestors(
            self.parentrevs, revs, stoprev=stoprev, inclusive=inclusive
        )

    # Cleanup opportunity: this is *identical* to the revlog.py version
    def descendants(self, revs):
        return dagop.descendantrevs(revs, self.revs, self.parentrevs)

    def reachableroots(self, minroot, heads, roots, includepath=False):
        return dagop._reachablerootspure(
            self.parentrevs, minroot, roots, heads, includepath
        )

    # Cleanup opportunity: this is *identical* to the revlog.py version
    def isancestor(self, a, b):
        a, b = self.rev(a), self.rev(b)
        return self.isancestorrev(a, b)

    # Cleanup opportunity: this is *identical* to the revlog.py version
    def isancestorrev(self, a, b):
        if a == nodemod.nullrev:
            return True
        elif a == b:
            return True
        elif a > b:
            return False
        return bool(self.reachableroots(a, [b], [a], includepath=False))

    def parentrevs(self, rev):
        n = self.node(rev)
        hn = gitutil.togitnode(n)
        c = self.gitrepo[hn]
        p1 = p2 = nodemod.nullrev
        if c.parents:
            p1 = self.rev(c.parents[0].id.raw)
            if len(c.parents) > 2:
                raise error.Abort(b'TODO octopus merge handling')
            if len(c.parents) == 2:
                p2 = self.rev(c.parents[0].id.raw)
        return p1, p2

    # Private method is used at least by the tags code.
    _uncheckedparentrevs = parentrevs

    def commonancestorsheads(self, a, b):
        # TODO the revlog verson of this has a C path, so we probably
        # need to optimize this...
        a, b = self.rev(a), self.rev(b)
        return [
            self.node(n)
            for n in ancestor.commonancestorsheads(self.parentrevs, a, b)
        ]

    def branchinfo(self, rev):
        """Git doesn't do named branches, so just put everything on default."""
        return b'default', False

    def delayupdate(self, tr):
        # TODO: I think we can elide this because we're just dropping
        # an object in the git repo?
        pass

    def add(
        self,
        manifest,
        files,
        desc,
        transaction,
        p1,
        p2,
        user,
        date=None,
        extra=None,
        p1copies=None,
        p2copies=None,
        filesadded=None,
        filesremoved=None,
    ):
        parents = []
        hp1, hp2 = gitutil.togitnode(p1), gitutil.togitnode(p2)
        if p1 != nodemod.nullid:
            parents.append(hp1)
        if p2 and p2 != nodemod.nullid:
            parents.append(hp2)
        assert date is not None
        timestamp, tz = date
        sig = pygit2.Signature(
            encoding.unifromlocal(stringutil.person(user)),
            encoding.unifromlocal(stringutil.email(user)),
            timestamp,
            -(tz // 60),
        )
        oid = self.gitrepo.create_commit(
            None, sig, sig, desc, gitutil.togitnode(manifest), parents
        )
        # Set up an internal reference to force the commit into the
        # changelog. Hypothetically, we could even use this refs/hg/
        # namespace to allow for anonymous heads on git repos, which
        # would be neat.
        self.gitrepo.references.create(
            'refs/hg/internal/latest-commit', oid, force=True
        )
        # Reindex now to pick up changes. We omit the progress
        # callback because this will be very quick.
        index._index_repo(self.gitrepo, self._db)
        return oid.raw


class manifestlog(baselog):
    def __getitem__(self, node):
        return self.get(b'', node)

    def get(self, relpath, node):
        if node == nodemod.nullid:
            # TODO: this should almost certainly be a memgittreemanifestctx
            return manifest.memtreemanifestctx(self, relpath)
        commit = self.gitrepo[gitutil.togitnode(node)]
        t = commit.tree
        if relpath:
            parts = relpath.split(b'/')
            for p in parts:
                te = t[p]
                t = self.gitrepo[te.id]
        return gitmanifest.gittreemanifestctx(self.gitrepo, t)


@interfaceutil.implementer(repository.ifilestorage)
class filelog(baselog):
    def __init__(self, gr, db, path):
        super(filelog, self).__init__(gr, db)
        assert isinstance(path, bytes)
        self.path = path

    def read(self, node):
        if node == nodemod.nullid:
            return b''
        return self.gitrepo[gitutil.togitnode(node)].data

    def lookup(self, node):
        if len(node) not in (20, 40):
            node = int(node)
        if isinstance(node, int):
            assert False, b'todo revnums for nodes'
        if len(node) == 40:
            node = nodemod.bin(node)
        hnode = gitutil.togitnode(node)
        if hnode in self.gitrepo:
            return node
        raise error.LookupError(self.path, node, _(b'no match found'))

    def cmp(self, node, text):
        """Returns True if text is different than content at `node`."""
        return self.read(node) != text

    def add(self, text, meta, transaction, link, p1=None, p2=None):
        assert not meta  # Should we even try to handle this?
        return self.gitrepo.create_blob(text).raw

    def __iter__(self):
        for clrev in self._db.execute(
            '''
SELECT rev FROM changelog
INNER JOIN changedfiles ON changelog.node = changedfiles.node
WHERE changedfiles.filename = ? AND changedfiles.filenode != ?
        ''',
            (pycompat.fsdecode(self.path), gitutil.nullgit),
        ):
            yield clrev[0]

    def linkrev(self, fr):
        return fr

    def rev(self, node):
        row = self._db.execute(
            '''
SELECT rev FROM changelog
INNER JOIN changedfiles ON changelog.node = changedfiles.node
WHERE changedfiles.filename = ? AND changedfiles.filenode = ?''',
            (pycompat.fsdecode(self.path), gitutil.togitnode(node)),
        ).fetchone()
        if row is None:
            raise error.LookupError(self.path, node, _(b'no such node'))
        return int(row[0])

    def node(self, rev):
        maybe = self._db.execute(
            '''SELECT filenode FROM changedfiles
INNER JOIN changelog ON changelog.node = changedfiles.node
WHERE changelog.rev = ? AND filename = ?
''',
            (rev, pycompat.fsdecode(self.path)),
        ).fetchone()
        if maybe is None:
            raise IndexError('gitlog %r out of range %d' % (self.path, rev))
        return nodemod.bin(maybe[0])

    def parents(self, node):
        gn = gitutil.togitnode(node)
        gp = pycompat.fsdecode(self.path)
        ps = []
        for p in self._db.execute(
            '''SELECT p1filenode, p2filenode FROM changedfiles
WHERE filenode = ? AND filename = ?
''',
            (gn, gp),
        ).fetchone():
            if p is None:
                commit = self._db.execute(
                    "SELECT node FROM changedfiles "
                    "WHERE filenode = ? AND filename = ?",
                    (gn, gp),
                ).fetchone()[0]
                # This filelog is missing some data. Build the
                # filelog, then recurse (which will always find data).
                if pycompat.ispy3:
                    commit = commit.decode('ascii')
                index.fill_in_filelog(self.gitrepo, self._db, commit, gp, gn)
                return self.parents(node)
            else:
                ps.append(nodemod.bin(p))
        return ps

    def renamed(self, node):
        # TODO: renames/copies
        return False