#!/usr/bin/env python
#
#    Copyright (c) 2009, 2010, 2011, 2012 Tom Keffer <tkeffer@gmail.com>
#
#    See the file LICENSE.txt for your full rights.
#
#    $Revision$
#    $Author$
#    $Date$
#
"""Configure the databases used by weewx"""
from __future__ import with_statement

import optparse
import sys
import syslog

import configobj

import user.extensions      #@UnusedImport
import weedb
import weewx.archive
import weewx.stats
import weewx.units
import weeutil.weeutil
import user.schemas

description="""Configures the weewx databases. Most of these functions are handled automatically
by weewx, but they may be useful as a utility in special cases. In particular, 
the 'reconfigure' option can be useful if you decide to add or drop data types
from the database schema or change unit systems."""
 
usage="""%prog: config_path [--help] [--create-database] 
                            [--create-stats] [--reconfigure] [--backfill-stats] """

epilog="""If you are using the MySQL database it is assumed that you have the appropriate
permissions for the requested operation."""

def main():

    # Set defaults for the system logger:
    syslog.openlog('config_database', syslog.LOG_PID|syslog.LOG_CONS)

    # Create a command line parser:
    parser = optparse.OptionParser(description=description, usage=usage, epilog=epilog)
    
    # Add the various options:
    parser.add_option("--create-archive", dest="create_archive", action='store_true',
                        help="Create the archive database.")
    parser.add_option("--create-stats", dest="create_stats", action='store_true',
                        help="Create the statistical database.")
    parser.add_option("--reconfigure", action='store_true',
                        help="""Create a new archive database using configuration information found """\
                        """in the configuration file. In particular, the new database will use the """\
                        """unit system found in option [StdConvert][target_unit]. It will use """\
                        """the schema found in './bin/user/schemas.py'. """\
                        """The new database will have the same name as the old database, with a '_new' on the end.""")
    parser.add_option("--backfill-stats", dest="backfill_stats", action='store_true',
                        help="Backfill the statistical database using the archive database")
    # Now we are ready to parse the command line:
    (options, args) = parser.parse_args()

    if not args:
        parser.error("Missing configuration file.")

    config_path = args[0]
    
    # Try to open up the configuration file. Declare an error if unable to.
    try :
        config_dict = configobj.ConfigObj(config_path, file_error=True)
    except IOError:
        print >>sys.stderr, "Unable to open configuration file ", config_path
        syslog.syslog(syslog.LOG_CRIT, "Unable to open configuration file %s" % config_path)
        exit(1)
    except configobj.ConfigObjError:
        print >>sys.stderr, "Error wile parsing configuration file %s" % config_path
        syslog.syslog(syslog.LOG_CRIT, "Error while parsing configuration file %s" % config_path)
        exit(1)

    syslog.syslog(syslog.LOG_INFO, "Using configuration file %s." % config_path)

    if options.create_archive:
        createMainDatabase(config_dict)
    
    if options.create_stats:
        createStatsDatabase(config_dict)
        
    if options.reconfigure:
        reconfigMainDatabase(config_dict)

    if options.backfill_stats:
        backfillStatsDatabase(config_dict)

def createMainDatabase(config_dict):
    """Create the main weewx archive database"""
    archive_db = config_dict['StdArchive']['archive_database']
    archive_db_dict = config_dict['Databases'][archive_db]
    
    # Try a simple open. If it succeeds, that means the database
    # exists and is initialized. Otherwise, an exception will be thrown.
    try:
        archive = weewx.archive.Archive.open(archive_db_dict)
        archive.close()
    except weedb.OperationalError:
        # Database does not exist. Do an open_with_create:
        archive = weewx.archive.Archive.open_with_create(archive_db_dict, user.schemas.defaultArchiveSchema)
        archive.close()
        print "Created database '%s'" % (archive_db,)
    else:
        print "Database '%s' already exists. Nothing done." % (archive_db,)

def createStatsDatabase(config_dict):
    """Create the weewx statistical database"""
    stats_db = config_dict['StdArchive']['stats_database']
    stats_db_dict = config_dict['Databases'][stats_db]
    try:
        stats = weewx.stats.StatsDb.open(stats_db_dict)
        stats.close()
    except weedb.OperationalError:
        stats_schema_str = config_dict['StdArchive'].get('stats_schema', 'user.schemas.defaultStatsSchema')
        stats_schema = weeutil.weeutil._get_object(stats_schema_str)
        stats = weewx.stats.StatsDb.open_with_create(stats_db_dict, stats_schema)
        stats.close()
        print "Created database '%s'" % (stats_db,)
    else:
        print "Database '%s' already exists. Nothing done." % (stats_db,)

def reconfigMainDatabase(config_dict):
    """Create a new database, then populate it with the contents of an old database"""

    archive_db = config_dict['StdArchive']['archive_database']
    old_archive_db_dict = config_dict['Databases'][archive_db]
    
    # For the new database, make a copy of the old database dictionary
    new_archive_db_dict = old_archive_db_dict.dict()
    # Now modify the database name
    new_archive_db_dict['database'] = new_archive_db_dict['database']+'_new'

    # First check and see if the new database already exists. If it does, check
    # with the user whether it's ok to delete it.
    try:
        weedb.create(new_archive_db_dict)
    except weedb.DatabaseExists:
        ans = None
        while ans not in ['y', 'n']:
            ans = raw_input("New database '%s' already exists. Delete it first (y/n)? " % (new_archive_db_dict['database'],))
            if ans == 'y':
                weedb.drop(new_archive_db_dict)
            elif ans == 'n':
                print "Nothing done."
                return

    # Get the unit system of the old archive:
    with weewx.archive.Archive.open(old_archive_db_dict) as old_archive:
        old_unit_system = old_archive.std_unit_system
    
    # Get the unit system of the new archive:
    try:
        target_unit_nickname = config_dict['StdConvert']['target_unit']
    except KeyError:
        target_unit_system = None
    else:
        target_unit_system = weewx.units.unit_constants[target_unit_nickname.upper()]
        
        
    ans = None
    while ans not in ['y', 'n']:
        print "Copying archive database '%s' to '%s'" % (old_archive_db_dict['database'], new_archive_db_dict['database'])
        if target_unit_system is None or old_unit_system==target_unit_system:
            print "The new archive will use the same unit system as the old ('%s')." % (weewx.units.unit_nicknames[old_unit_system],)
        else:
            print "Units will be converted from the '%s' system to the '%s' system." % (weewx.units.unit_nicknames[old_unit_system],
                                                                                        weewx.units.unit_nicknames[target_unit_system])
        ans = raw_input("Are you sure you wish to proceed (y/n)? ")
        if ans == 'y':
            weewx.archive.reconfig(old_archive_db_dict, new_archive_db_dict, target_unit_system)
        elif ans == 'n':
            print "Nothing done."
    
def backfillStatsDatabase(config_dict):
    """Use the main archive database to backfill the stats database."""

    archive_db = config_dict['StdArchive']['archive_database']
    archive_db_dict = config_dict['Databases'][archive_db]
    stats_db = config_dict['StdArchive']['stats_database']
    stats_db_dict = config_dict['Databases'][stats_db]
    stats_schema_str = config_dict['StdArchive'].get('stats_schema', 'user.schemas.defaultStatsSchema')
    stats_schema = weeutil.weeutil._get_object(stats_schema_str)

    # Open up the main database archive
    with weewx.archive.Archive.open(archive_db_dict) as archive:

        # Open up the Stats database. This will create it if it doesn't already exist.
        with weewx.stats.StatsDb.open_with_create(stats_db_dict, stats_schema) as statsDb:
            # Now backfill
            nrecs = statsDb.backfillFrom(archive)

    print "Backfilled %d records from the archive database '%s' into the statistical database '%s'" % (nrecs, archive.database, statsDb.database)
    
if __name__=="__main__" :
    main()