from __future__ import absolute_import

import threading

from mercurial.node import hex, nullid

from mercurial import (

    mdiff,

    pycompat,

    revlog,

)

from . import (

    basestore,

    constants,

    shallowutil,

)

class ChainIndicies(object):

    """A static class for easy reference to the delta chain indicies.

    """

    # The filename of this revision delta

    NAME = 0

    # The mercurial file node for this revision delta

    NODE = 1

    # The filename of the delta base's revision. This is useful when delta

    # between different files (like in the case of a move or copy, we can delta

    # against the original file content).

    BASENAME = 2

    # The mercurial file node for the delta base revision. This is the nullid if

    # this delta is a full text.

    BASENODE = 3

    # The actual delta or full text data.

    DATA = 4

class unioncontentstore(basestore.baseunionstore):

    def __init__(self, *args, **kwargs):

        super(unioncontentstore, self).__init__(*args, **kwargs)

        self.stores = args

        self.writestore = kwargs.get('writestore')

        # If allowincomplete==True then the union store can return partial

        # delta chains, otherwise it will throw a KeyError if a full

        # deltachain can't be found.

        self.allowincomplete = kwargs.get('allowincomplete', False)

    def get(self, name, node):

        """Fetches the full text revision contents of the given name+node pair.

        If the full text doesn't exist, throws a KeyError.

        Under the hood, this uses getdeltachain() across all the stores to build

        up a full chain to produce the full text.

        """

        chain = self.getdeltachain(name, node)

        if chain[-1][ChainIndicies.BASENODE] != nullid:

            # If we didn't receive a full chain, throw

            raise KeyError((name, hex(node)))

        # The last entry in the chain is a full text, so we start our delta

        # applies with that.

        fulltext = chain.pop()[ChainIndicies.DATA]

        text = fulltext

        while chain:

            delta = chain.pop()[ChainIndicies.DATA]

            text = mdiff.patches(text, [delta])

        return text

    @basestore.baseunionstore.retriable

    def getdelta(self, name, node):

        """Return the single delta entry for the given name/node pair.

        """

        for store in self.stores:

            try:

                return store.getdelta(name, node)

            except KeyError:

                pass

        raise KeyError((name, hex(node)))

    def getdeltachain(self, name, node):

        """Returns the deltachain for the given name/node pair.

        Returns an ordered list of:

          [(name, node, deltabasename, deltabasenode, deltacontent),...]

        where the chain is terminated by a full text entry with a nullid

        deltabasenode.

        """

        chain = self._getpartialchain(name, node)

        while chain[-1][ChainIndicies.BASENODE] != nullid:

            x, x, deltabasename, deltabasenode, x = chain[-1]

            try:

                morechain = self._getpartialchain(deltabasename, deltabasenode)

                chain.extend(morechain)

            except KeyError:

                # If we allow incomplete chains, don't throw.

                if not self.allowincomplete:

                    raise

                break

        return chain

    @basestore.baseunionstore.retriable

    def getmeta(self, name, node):

        """Returns the metadata dict for given node."""

        for store in self.stores:

            try:

                return store.getmeta(name, node)

            except KeyError:

                pass

        raise KeyError((name, hex(node)))

    def getmetrics(self):

        metrics = [s.getmetrics() for s in self.stores]

        return shallowutil.sumdicts(*metrics)

    @basestore.baseunionstore.retriable

    def _getpartialchain(self, name, node):

        """Returns a partial delta chain for the given name/node pair.

        A partial chain is a chain that may not be terminated in a full-text.

        """

        for store in self.stores:

            try:

                return store.getdeltachain(name, node)

            except KeyError:

                pass

        raise KeyError((name, hex(node)))

    def add(self, name, node, data):

        raise RuntimeError("cannot add content only to remotefilelog "

                           "contentstore")

    def getmissing(self, keys):

        missing = keys

        for store in self.stores:

            if missing:

                missing = store.getmissing(missing)

        return missing

    def addremotefilelognode(self, name, node, data):

        if self.writestore:

            self.writestore.addremotefilelognode(name, node, data)

        else:

            raise RuntimeError("no writable store configured")

    def markledger(self, ledger, options=None):

        for store in self.stores:

            store.markledger(ledger, options)

class remotefilelogcontentstore(basestore.basestore):

    def __init__(self, *args, **kwargs):

        super(remotefilelogcontentstore, self).__init__(*args, **kwargs)

        self._threaddata = threading.local()

    def get(self, name, node):

        # return raw revision text

        data = self._getdata(name, node)

        offset, size, flags = shallowutil.parsesizeflags(data)

        content = data[offset:offset + size]

        ancestormap = shallowutil.ancestormap(data)

        p1, p2, linknode, copyfrom = ancestormap[node]

        copyrev = None

        if copyfrom:

            copyrev = hex(p1)

        self._updatemetacache(node, size, flags)

        # lfs tracks renames in its own metadata, remove hg copy metadata,

        # because copy metadata will be re-added by lfs flag processor.

        if flags & revlog.REVIDX_EXTSTORED:

            copyrev = copyfrom = None

        revision = shallowutil.createrevlogtext(content, copyfrom, copyrev)

        return revision

    def getdelta(self, name, node):

        # Since remotefilelog content stores only contain full texts, just

        # return that.

        revision = self.get(name, node)

        return revision, name, nullid, self.getmeta(name, node)

    def getdeltachain(self, name, node):

        # Since remotefilelog content stores just contain full texts, we return

        # a fake delta chain that just consists of a single full text revision.

        # The nullid in the deltabasenode slot indicates that the revision is a

        # fulltext.

        revision = self.get(name, node)

        return [(name, node, None, nullid, revision)]

    def getmeta(self, name, node):

        self._sanitizemetacache()

        if node != self._threaddata.metacache[0]:

            data = self._getdata(name, node)

            offset, size, flags = shallowutil.parsesizeflags(data)

            self._updatemetacache(node, size, flags)

        return self._threaddata.metacache[1]

    def add(self, name, node, data):

        raise RuntimeError("cannot add content only to remotefilelog "

                           "contentstore")

    def _sanitizemetacache(self):

        metacache = getattr(self._threaddata, 'metacache', None)

        if metacache is None:

            self._threaddata.metacache = (None, None) # (node, meta)

    def _updatemetacache(self, node, size, flags):

        self._sanitizemetacache()

        if node == self._threaddata.metacache[0]:

            return

        meta = {constants.METAKEYFLAG: flags,

                constants.METAKEYSIZE: size}

        self._threaddata.metacache = (node, meta)

class remotecontentstore(object):

    def __init__(self, ui, fileservice, shared):

        self._fileservice = fileservice

        # type(shared) is usually remotefilelogcontentstore

        self._shared = shared

    def get(self, name, node):

        self._fileservice.prefetch([(name, hex(node))], force=True,

                                   fetchdata=True)

        return self._shared.get(name, node)

    def getdelta(self, name, node):

        revision = self.get(name, node)

        return revision, name, nullid, self._shared.getmeta(name, node)

    def getdeltachain(self, name, node):

        # Since our remote content stores just contain full texts, we return a

        # fake delta chain that just consists of a single full text revision.

        # The nullid in the deltabasenode slot indicates that the revision is a

        # fulltext.

        revision = self.get(name, node)

        return [(name, node, None, nullid, revision)]

    def getmeta(self, name, node):

        self._fileservice.prefetch([(name, hex(node))], force=True,

                                   fetchdata=True)

        return self._shared.getmeta(name, node)

    def add(self, name, node, data):

        raise RuntimeError("cannot add to a remote store")

    def getmissing(self, keys):

        return keys

    def markledger(self, ledger, options=None):

        pass

class manifestrevlogstore(object):

    def __init__(self, repo):

        self._store = repo.store

        self._svfs = repo.svfs

        self._revlogs = dict()

        self._cl = revlog.revlog(self._svfs, '00changelog.i')

        self._repackstartlinkrev = 0

    def get(self, name, node):

        return self._revlog(name).revision(node, raw=True)

    def getdelta(self, name, node):

        revision = self.get(name, node)

        return revision, name, nullid, self.getmeta(name, node)

    def getdeltachain(self, name, node):

        revision = self.get(name, node)

        return [(name, node, None, nullid, revision)]

    def getmeta(self, name, node):

        rl = self._revlog(name)

        rev = rl.rev(node)

        return {constants.METAKEYFLAG: rl.flags(rev),

                constants.METAKEYSIZE: rl.rawsize(rev)}

    def getancestors(self, name, node, known=None):

        if known is None:

            known = set()

        if node in known:

            return []

        rl = self._revlog(name)

        ancestors = {}

        missing = set((node,))

        for ancrev in rl.ancestors([rl.rev(node)], inclusive=True):

            ancnode = rl.node(ancrev)

            missing.discard(ancnode)

            p1, p2 = rl.parents(ancnode)

            if p1 != nullid and p1 not in known:

                missing.add(p1)

            if p2 != nullid and p2 not in known:

                missing.add(p2)

            linknode = self._cl.node(rl.linkrev(ancrev))

            ancestors[rl.node(ancrev)] = (p1, p2, linknode, '')

            if not missing:

                break

        return ancestors

    def getnodeinfo(self, name, node):

        cl = self._cl

        rl = self._revlog(name)

        parents = rl.parents(node)

        linkrev = rl.linkrev(rl.rev(node))

        return (parents[0], parents[1], cl.node(linkrev), None)

    def add(self, *args):

        raise RuntimeError("cannot add to a revlog store")

    def _revlog(self, name):

        rl = self._revlogs.get(name)

        if rl is None:

            revlogname = '00manifesttree.i'

            if name != '':

                revlogname = 'meta/%s/00manifest.i' % name

            rl = revlog.revlog(self._svfs, revlogname)

            self._revlogs[name] = rl

        return rl

    def getmissing(self, keys):

        missing = []

        for name, node in keys:

            mfrevlog = self._revlog(name)

            if node not in mfrevlog.nodemap:

                missing.append((name, node))

        return missing

    def setrepacklinkrevrange(self, startrev, endrev):

        self._repackstartlinkrev = startrev

        self._repackendlinkrev = endrev

    def markledger(self, ledger, options=None):

        if options and options.get(constants.OPTION_PACKSONLY):

            return

        treename = ''

        rl = revlog.revlog(self._svfs, '00manifesttree.i')

        startlinkrev = self._repackstartlinkrev

        endlinkrev = self._repackendlinkrev

        for rev in pycompat.xrange(len(rl) - 1, -1, -1):

            linkrev = rl.linkrev(rev)

            if linkrev < startlinkrev:

                break

            if linkrev > endlinkrev:

                continue

            node = rl.node(rev)

            ledger.markdataentry(self, treename, node)

            ledger.markhistoryentry(self, treename, node)

        for path, encoded, size in self._store.datafiles():

            if path[:5] != 'meta/' or path[-2:] != '.i':

                continue

            treename = path[5:-len('/00manifest.i')]

            rl = revlog.revlog(self._svfs, path)

            for rev in pycompat.xrange(len(rl) - 1, -1, -1):

                linkrev = rl.linkrev(rev)

                if linkrev < startlinkrev:

                    break

                if linkrev > endlinkrev:

                    continue

                node = rl.node(rev)

                ledger.markdataentry(self, treename, node)

                ledger.markhistoryentry(self, treename, node)

    def cleanup(self, ledger):

        pass