#
# Copyright (c) 2003 Martynas Sklyzmantas, Andrey Lebedev <andrey@micro.lt>
#
# This module is free software, and you may redistribute it and/or modify
# under the same terms as Python, so long as this copyright message and
# disclaimer are retained in their original form.
#
'''Postgresql backend via psycopg for Roundup.'''
__docformat__ = 'restructuredtext'

import os, shutil, popen2, time
import psycopg

from roundup import hyperdb, date
from roundup.backends import rdbms_common

def db_create(config):
    """Clear all database contents and drop database itself"""
    if __debug__:
        print >> hyperdb.DEBUG, '+++ create database +++'
    command = 'CREATE DATABASE %s'%config.POSTGRESQL_DATABASE['database']
    db_command(config, command)

def db_nuke(config, fail_ok=0):
    """Clear all database contents and drop database itself"""
    if __debug__:
        print >> hyperdb.DEBUG, '+++ nuke database +++'
    command = 'DROP DATABASE %s'% config.POSTGRESQL_DATABASE['database']
    db_command(config, command)

    if os.path.exists(config.DATABASE):
        shutil.rmtree(config.DATABASE)

def db_command(config, command):
    '''Perform some sort of database-level command. Retry 10 times if we
    fail by conflicting with another user.
    '''
    template1 = config.POSTGRESQL_DATABASE.copy()
    template1['database'] = 'template1'
    
    try:
        conn = psycopg.connect(**template1)
    except psycopg.OperationalError, message:
        raise hyperdb.DatabaseError, message
    
    conn.set_isolation_level(0)
    cursor = conn.cursor()
    try:
        for n in range(10):
            if pg_command(cursor, command):
                return
    finally:
        conn.close()
    raise RuntimeError, '10 attempts to create database failed'

def pg_command(cursor, command):
    '''Execute the postgresql command, which may be blocked by some other
    user connecting to the database, and return a true value if it succeeds.
    '''
    try:
        cursor.execute(command)
    except psycopg.ProgrammingError, err:
        response = str(err).split('\n')[0]
        if response.find('FATAL') != -1:
            raise RuntimeError, response
        elif response.find('ERROR') != -1:
            if response.find('is being accessed by other users') == -1:
                raise RuntimeError, response
            if __debug__:
                print >> hyperdb.DEBUG, '+++ SLEEPING +++'
            time.sleep(1)
            return 0
    return 1

def db_exists(config):
    """Check if database already exists"""
    db = getattr(config, 'POSTGRESQL_DATABASE')
    try:
        conn = psycopg.connect(**db)
        conn.close()
        if __debug__:
            print >> hyperdb.DEBUG, '+++ database exists +++'
        return 1
    except:
        if __debug__:
            print >> hyperdb.DEBUG, '+++ no database +++'
        return 0

class Database(rdbms_common.Database):
    arg = '%s'

    def sql_open_connection(self):
        db = getattr(self.config, 'POSTGRESQL_DATABASE')
        try:
            conn = psycopg.connect(**db)
        except psycopg.OperationalError, message:
            raise hyperdb.DatabaseError, message

        cursor = conn.cursor()

        return (conn, cursor)

    def open_connection(self):
        if not db_exists(self.config):
            db_create(self.config)

        if __debug__:
            print >>hyperdb.DEBUG, '+++ open database connection +++'

        self.conn, self.cursor = self.sql_open_connection()

        try:
            self.load_dbschema()
        except:
            self.rollback()
            self.init_dbschema()
            self.sql("CREATE TABLE schema (schema TEXT)")
            self.sql("CREATE TABLE dual (dummy integer)")
            self.sql("insert into dual values (1)")
            self.create_version_2_tables()

    def create_version_2_tables(self):
        # OTK store
        self.cursor.execute('''CREATE TABLE otks (otk_key VARCHAR(255),
            otk_value VARCHAR(255), otk_time REAL)''')
        self.cursor.execute('CREATE INDEX otks_key_idx ON otks(otk_key)')

        # Sessions store
        self.cursor.execute('''CREATE TABLE sessions (
            session_key VARCHAR(255), session_time REAL,
            session_value VARCHAR(255))''')
        self.cursor.execute('''CREATE INDEX sessions_key_idx ON
            sessions(session_key)''')

        # full-text indexing store
        self.cursor.execute('CREATE SEQUENCE ___textids_ids')
        self.cursor.execute('''CREATE TABLE __textids (
            _textid integer primary key, _class VARCHAR(255),
            _itemid VARCHAR(255), _prop VARCHAR(255))''')
        self.cursor.execute('''CREATE TABLE __words (_word VARCHAR(30), 
            _textid integer)''')
        self.cursor.execute('CREATE INDEX words_word_idx ON __words(_word)')

    def fix_version_2_tables(self):
        # Convert journal date column to TIMESTAMP, params column to TEXT
        self._convert_journal_tables()

        # Convert all String properties to TEXT
        self._convert_string_properties()

        # convert session / OTK *_time columns to REAL
        c = self.cursor
        for name in ('otk', 'session'):
            c.execute('drop index %ss_key_idx'%name)
            c.execute('drop table %ss'%name)
            c.execute('''CREATE TABLE %ss (%s_key VARCHAR(255),
                %s_value VARCHAR(255), %s_time REAL)'''%(name, name, name,
                name))
            c.execute('CREATE INDEX %ss_key_idx ON %ss(%s_key)'%(name, name,
                name))

    def add_actor_column(self):
        # update existing tables to have the new actor column
        tables = self.database_schema['tables']
        for name in tables.keys():
            self.cursor.execute('ALTER TABLE _%s add __actor '
                'VARCHAR(255)'%name)

    def __repr__(self):
        return '<roundpsycopgsql 0x%x>' % id(self)

    def sql_stringquote(self, value):
        ''' psycopg.QuotedString returns a "buffer" object with the
            single-quotes around it... '''
        return str(psycopg.QuotedString(str(value)))[1:-1]

    def sql_index_exists(self, table_name, index_name):
        sql = 'select count(*) from pg_indexes where ' \
            'tablename=%s and indexname=%s'%(self.arg, self.arg)
        self.cursor.execute(sql, (table_name, index_name))
        return self.cursor.fetchone()[0]

    def create_class_table(self, spec, create_sequence=1):
        if create_sequence:
            sql = 'CREATE SEQUENCE _%s_ids'%spec.classname
            if __debug__:
                print >>hyperdb.DEBUG, 'create_class_table', (self, sql)
            self.cursor.execute(sql)

        return rdbms_common.Database.create_class_table(self, spec)

    def drop_class_table(self, cn):
        sql = 'drop table _%s'%cn
        if __debug__:
            print >>hyperdb.DEBUG, 'drop_class', (self, sql)
        self.cursor.execute(sql)

        sql = 'drop sequence _%s_ids'%cn
        if __debug__:
            print >>hyperdb.DEBUG, 'drop_class', (self, sql)
        self.cursor.execute(sql)

    def newid(self, classname):
        sql = "select nextval('_%s_ids') from dual"%classname
        if __debug__:
            print >>hyperdb.DEBUG, 'setid', (self, sql)
        self.cursor.execute(sql)
        return self.cursor.fetchone()[0]

    def setid(self, classname, setid):
        sql = "select setval('_%s_ids', %s) from dual"%(classname, int(setid))
        if __debug__:
            print >>hyperdb.DEBUG, 'setid', (self, sql)
        self.cursor.execute(sql)


class Class(rdbms_common.Class):
    pass
class IssueClass(rdbms_common.IssueClass):
    pass
class FileClass(rdbms_common.FileClass):
    pass