#!/usr/bin/env python

# -*- coding: utf-8 -*-
#
# Copyright (C) 2008 John Hampton <pacopablo@pacopablo.com>
# All rights reserved.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at http://trac.edgewall.com/license.html.
#
# This software consists of voluntary contributions made by many
# individuals. For the exact contribution history, see the revision
# history and logs, available at:
# http://trac-hacks.org/wiki/SqliteToPgScript
#
# Basically, it boils down to: feel free to use/modify/distribute/etc.
# However, give me credit where due.  Also, if you like the script and
# find it useful, buy me a soda or candy bar or something if ever we
# meet. Thanks and enjoy.
#
# Author: John Hampton <pacopablo@pacopablo.com>


import os, os.path, sys
from trac.env import Environment, EnvironmentSetup, IEnvironmentSetupParticipant
from trac.core import ComponentMeta
from trac.db import DatabaseManager
from optparse import OptionParser
from psycopg2 import ProgrammingError, IntegrityError
from psycopg2.extensions import ISOLATION_LEVEL_AUTOCOMMIT

VERSION='0.10'

class TableMigration(object):
    """
        Class to conatin all table migration functions
    """
    def __init__(self, sqlenv, pgenv, opts):
        """ Create a TableMigration instance.  Required are SQLite and
            PostgreSQL environment objects
        """
        self.sqlenv = sqlenv
        self.pgenv = pgenv
        self.opts = opts
        self.sdb = self.sqlenv.get_db_cnx()
        self.pgdb = self.pgenv.get_db_cnx()
        self.pgdb_schema = self.pgdb.schema
        pass

    def lookupMethod(self, table):
        """ Get a reference to the function that handles migration for the
            specified table
        """
        m = getattr(self, ''.join(['migrate_', table.upper()]), None)
        if not m:
            m = self.default_copy 
        return m

    def cleanTable(self, table):
        """ Clear the contents of the table """
        cur = self.pgdb.cursor()
        delete_from = "DELETE FROM %s" % table
        cur.execute(delete_from)

    def migrateTable(self, table):
        """ Migrate the table specified. """
        if not self.opts.noclean:
            self.cleanTable(table)
        m = getattr(self, ''.join(['migrate_', table.upper()]), None)
        if not m:
            rc = self.default_copy(table)
        else:
            rc = m()
        return rc

    def default_copy(self, table):
        """ Copy the table from the sqlite db to the postgresql db """
        select_all = "SELECT * FROM %s" % table
        scur = self.sdb.cursor()
        pgcur = self.pgdb.cursor()
        scur.execute(select_all)
        cols = scur.description
        if not cols:
            return True
        subs = ["%s" for x in range(len(cols))]
        insert_into = ''.join([ "INSERT INTO ", table, " VALUES (",
                                ','.join(subs), ")"])
        rows = row_exists = 0
        for row in scur:
            rows += 1
            try:
                pgcur.execute(insert_into, row)
            except (ProgrammingError, IntegrityError):
                row_exists += 1
            continue
        if row_exists:
            print "%s of %s rows already existed in the %s table" % \
                  (str(row_exists), str(rows), table)
        self.pgdb.commit()
        return row_exists > 0

    def migrate_TICKET(self):
        """ Migrate the ticket table and adjust the sequences properly """
        self.default_copy('ticket')
        select_maxticket = "SELECT max(id) FROM ticket"
        pgcur = self.pgdb.cursor()
        pgcur.execute(select_maxticket)
        r = pgcur.fetchone()
        if r:
            pgcur.execute("SELECT setval('ticket_id_seq', %s)", r)
        self.pgdb.commit()
        
    def migrate_REPORT(self):
        """ Migrate the report table and adjust the sequences properly """
        self.default_copy('report')
        select_maxreport = "SELECT max(id) FROM report"
        pgcur = self.pgdb.cursor()
        pgcur.execute(select_maxreport)
        r = pgcur.fetchone()
        if r:
            pgcur.execute("SELECT setval('report_id_seq', %s)", r)
        self.pgdb.commit()
    
    def migrate_PERMISSION(self):
        """
            Migrate permission table
        """
        scur = self.sdb.cursor()
        pgcur = self.pgdb.cursor()
        rows = row_exists = 0
        if not self.opts.plist:
            sql_select = "SELECT * FROM permission"
        else:
            subs = []
            for x in range(len(self.opts.plist)):
                subs.append("%s")
                continue
            sql_select = ''.join([  "SELECT * FROM permission ",
                                    "WHERE username NOT IN (",
                                    ','.join(subs),
                                    ")",
                                 ])
        
        scur.execute(sql_select, self.opts.plist)
        sql_insert = "INSERT INTO permission VALUES (%s, %s)"
        for row in scur:
            rows += 1
            try:
                pgcur.execute(sql_insert, row)
            except (ProgrammingError, IntegrityError):
                row_exists += 1
            continue
        if row_exists:
            print "%s of %s rows already existed in the permission table" % (str(row_exists), str(rows))
        self.pgdb.commit()
        return row_exists > 0

    def migrate_WIKI(self):
        """
            Migrate wiki table
        """
        scur = self.sdb.cursor()
        pgcur = self.pgdb.cursor()
        rows = row_exists = 0
        if not self.opts.wlist:
            sql_select = "SELECT * FROM wiki"
        else:
            subs = []
            for x in range(len(self.opts.wlist)):
                subs.append("%s")
                continue
            sql_select = ''.join([  "SELECT * FROM wiki ",
                                    "WHERE name NOT IN (",
                                    ','.join(subs),
                                    ")",
                                 ])
        
        scur.execute(sql_select, self.opts.wlist)
        sql_insert = "INSERT INTO wiki VALUES (%s, %s, %s, %s, %s, %s, %s, %s)"
        for row in scur:
            rows += 1
            try:
                pgcur.execute(sql_insert, row)
            except (ProgrammingError, IntegrityError):
                row_exists += 1
            continue
        if row_exists:
            print "%s of %s rows already existed in the wiki table" % (str(row_exists), str(rows))
        self.pgdb.commit()
        return row_exists > 0


def getSQLiteEnvironment(opts): 
    """ Create an Environment connected to the SQLite database """

    dburi = opts.sqlite_uri
    env = Environment(opts.tracenv)
    env.config.set('trac', 'database', dburi)
    return env

def getPostgreSQLEnvironment(opts):
    """ Create an Environment connected to the PostgreSQL database """

    dburi = opts.pg_uri
    env = Environment(opts.tracenv)
    env.config.set('trac', 'database', dburi)
    try:
        cnx = env.get_db_cnx()
        cur = cnx.cursor()
        cur.execute("select value from system where name = 'database_version'");
    except ProgrammingError:
        cnx.rollback()
        DatabaseManager(env).init_db()
        DatabaseManager(env).shutdown()
        for x in filter(None, [env.compmgr[cls] for cls in 
                        ComponentMeta._registry.get(
                        IEnvironmentSetupParticipant, [])]):
            if isinstance(x, EnvironmentSetup):
                x.environment_created()        
    if env.needs_upgrade():
        env.upgrade()
    return env

def getAllTables(env):
    """ Queries the PostgreSQL database for a list of tables """
    cnx = env.get_db_cnx()
    schema = cnx.schema or u'public'
    cur = cnx.cursor()
    select_tables = """SELECT tablename 
                         FROM pg_catalog.pg_tables 
                        WHERE schemaname = %s"""
    cur.execute(select_tables, (schema,))
    cnx.commit()
    return [table[0] for table in cur]

def Main(opts):
    """
        Migrate data from SQLite to PostgreSQL
    """
    rc = 0

    sqlenv = getSQLiteEnvironment(opts)
    pgenv = getPostgreSQLEnvironment(opts)
    tmigration = TableMigration(sqlenv, pgenv, opts)
    if not opts.tlist:
        opts.tlist = getAllTables(pgenv)
    for tname in opts.tlist:
        try:
            rc = tmigration.migrateTable(tname) or rc
        except AttributeError:
            print "Migration of %s has not been implemented" % tname
            pass
        continue
   
    return rc

def doArgs(argv):
    """ Look if you can't guess what this function does, just give up now. """
    global VERSION
   
    version = "%%prog %s" % VERSION
    usage ="usage: %prog [options] [site]"
    description="%prog is used to migrate data from SQLite to PostgreSQL."
   
    parser = OptionParser(usage=usage, version=version, description=description)
   
    parser.add_option("-t", "--tracbase", dest="tracbase", type="string",
                        help="Parent path for trac sites",
                        metavar="<path>")
    parser.add_option("-e", "--tracenv", dest="tracenv", type="string",
                        help="Path to trac environment",
                        metavar="<path>")
    parser.add_option("-m", "--migrate", dest="migrate", type="string",
                        help="Comma separated list of tables to migrate",
                        metavar="<list>", default=None)
    parser.add_option("", "--exclude_perms", dest="perms_exclude", 
                        type="string", help="Comma separated list of users to "
                        "exclude from permission migration", metavar="<list>")
    parser.add_option("-w", "--wikipages", dest="wikipages", type="string",
                        help="Comma separated list of wiki page names to "
                        "ommit from the migration", metavar="<list>")
    parser.add_option("-p", "--pg_uri", dest="pg_uri", type="string",
                        help="DB URI for PostgreSQL database",
                        metavar="<uri>")
    parser.add_option("-s", "--sqlite_uri", dest="sqlite_uri", type="string",
                        help="DB URI for SQLite database",
                        metavar="<uri>", default="sqlite:db/trac.db")
    parser.add_option("", "--noclean", dest="noclean", action="store_true",
                        help="Do not clear PostgreSQL tables before transfer",
                        default=False)
   
    (options, args) = parser.parse_args(argv)
    if not options.tracenv:
        if  not options.tracbase:
            print ("You must specify the --tracenv or the --tracbase option")
            sys.exit(1)
        else:
            if len(args) < 1:
                print ("You must specify a project name\n")
                sys.exit(1)
            options.project = args[0]
            options.tracenv = os.path.join(options.tracbase, args[0])

    if not options.pg_uri or not options.pg_uri.startswith('postgres://'):
        print ("You must specify a valid URI for the PostgreSQL database.")
        print ("  eg. postgres://user:password@localhost/dbname")
        sys.exit(1)
 
    if not options.sqlite_uri or not options.sqlite_uri.startswith('sqlite:'):
        print ("You must specify a valid URI for the SQLite database.")
        print ("  eg. sqlite:db/trac.db")
        sys.exit(1)


    options.args = args
    options.tlist = options.migrate and \
                    [t.strip() for t in options.migrate.strip().split(',')]
    options.wlist = options.wikipages and \
                    [w.strip() for w in options.wikipages.strip().split(',')] \
                    or []
    options.plist = options.perms_exclude and \
                    [p.strip() for p in options.perms_exclude.strip().split(',')] \
                    or []

    return options


def main(argv):
    opts = doArgs(argv)
    Main(opts)
    return 0

if __name__ == '__main__':
    sys.exit(main(sys.argv[1:]))