# Copyright 2018 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

# Standard Library
import hashlib
import json

from mercurial.i18n import _

from . import commitcloudcommon, commitcloudutil
from .. import shareutil


class SyncState(object):
    """
    Stores the local record of what state was stored in the cloud at the
    last sync.
    """

    @staticmethod
    def _filename(workspace):
        # make a unique valid filename
        return (
            "commitcloudstate."
            + "".join(x for x in workspace if x.isalnum())
            + ".%s" % (hashlib.sha256(workspace).hexdigest()[0:5])
        )

    @staticmethod
    def erasestate(repo):
        # get current workspace
        workspace = commitcloudutil.getworkspacename(repo)
        if not workspace:
            raise commitcloudcommon.WorkspaceError(repo.ui, _("undefined workspace"))

        filename = SyncState._filename(workspace)
        # clean up the current state in force recover mode
        if repo.svfs.exists(filename):
            with repo.wlock(), repo.lock():
                repo.svfs.unlink(filename)

    def __init__(self, repo):
        # get current workspace
        workspace = commitcloudutil.getworkspacename(repo)
        if not workspace:
            raise commitcloudcommon.WorkspaceError(repo.ui, _("undefined workspace"))

        self.filename = SyncState._filename(workspace)
        repo = shareutil.getsrcrepo(repo)
        self.repo = repo
        if repo.svfs.exists(self.filename):
            with repo.svfs.open(self.filename, "r") as f:
                try:
                    data = json.load(f)
                except Exception:
                    raise commitcloudcommon.InvalidWorkspaceDataError(
                        repo.ui, _("failed to parse %s") % self.filename
                    )

                self.version = data["version"]
                self.heads = [h.encode() for h in data["heads"]]
                self.bookmarks = {
                    n.encode("utf-8"): v.encode() for n, v in data["bookmarks"].items()
                }
        else:
            self.version = 0
            self.heads = []
            self.bookmarks = {}

    def update(self, newversion, newheads, newbookmarks):
        data = {"version": newversion, "heads": newheads, "bookmarks": newbookmarks}
        with self.repo.wlock(), self.repo.lock():
            with self.repo.svfs.open(self.filename, "w", atomictemp=True) as f:
                json.dump(data, f)
        self.version = newversion
        self.heads = newheads
        self.bookmarks = newbookmarks