# -*- coding: utf-8
#
# manage journaldb.json which is a table of vmid's as indexes update on vmcreate and
# values of region_id and slave_id. should support deletion of unused id's and be
# properly updated on vm migrations

#site
import json

#local
import ioconfig
import utils

def createjnode(vmid, regionid, slaveid):
    """ create new record into the journal. invoked on vm creation """
    journaldb = readjournal()
    if str(vmid) in journaldb:
        ioconfig.logger.warning('journal> overwriting id[{}] !'.format(vmid))
    else:
        jnode = { str(vmid):{} }
        journaldb.update(jnode)

    ioconfig.logger.info ('journal> r[{}] s[{}] -> id[{}]'.format(regionid, slaveid, vmid))
    jdata = { 'vmid':str(vmid), 'slaveid':str(slaveid), 'regionid':str(regionid) }
    journaldb[str(vmid)] = jdata
    writedb(journaldb)


def getjnode(vmid):
    """ query the database for records with requested vmid. invoked on user commands """
    journaldb = readjournal()
    try:
        regionid = journaldb[str(vmid)]['regionid']
        slaveid = journaldb[str(vmid)]['slaveid']
        ioconfig.logger.info('journal> read: id[{}] -> r[{}] s[{}]'.format(vmid, regionid, slaveid))
    except:
        ioconfig.logger.error('journal> invalid id[{}] !'.format(vmid))
    else:
        return regionid, slaveid 


def readjournal():
    """ read journal """
    try:
        with open('journal.json') as dbr:
            journaldb = json.load(dbr)
        dbr.close()
    except:
        journaldb = {}
        ioconfig.logger.warning('journal> initializing...')
    return journaldb


def writedb(journaldb):
    """ write journal """
    with open('journal.json', 'w') as dbw:
        json.dump(journaldb, dbw)
    dbw.close()