# This file is part of Tryton.  The COPYRIGHT file at the top level of
# this repository contains the full copyright notices and license terms.
import time
import logging
import re
import os
import urllib
import json
from decimal import Decimal
from threading import RLock

try:
    from psycopg2cffi import compat
    compat.register()
except ImportError:
    pass
from psycopg2 import connect, Binary
from psycopg2.pool import ThreadedConnectionPool, PoolError
from psycopg2.extensions import cursor
from psycopg2.extensions import ISOLATION_LEVEL_REPEATABLE_READ
from psycopg2.extensions import ISOLATION_LEVEL_AUTOCOMMIT
from psycopg2.extensions import register_type, register_adapter
from psycopg2.extensions import UNICODE, AsIs
try:
    from psycopg2.extensions import PYDATE, PYDATETIME, PYTIME, PYINTERVAL
except ImportError:
    PYDATE, PYDATETIME, PYTIME, PYINTERVAL = None, None, None, None
from psycopg2 import IntegrityError as DatabaseIntegrityError
from psycopg2 import OperationalError as DatabaseOperationalError
from psycopg2.extras import register_default_json, register_default_jsonb

from sql import Flavor

from trytond.backend.database import DatabaseInterface, SQLType
from trytond.config import config, parse_uri
from trytond.protocols.jsonrpc import JSONDecoder

__all__ = ['Database', 'DatabaseIntegrityError', 'DatabaseOperationalError']

logger = logging.getLogger(__name__)

RE_VERSION = re.compile(r'\S+ (\d+)\.(\d+)')

os.environ['PGTZ'] = os.environ.get('TZ', '')


def unescape_quote(s):
    if s.startswith('"') and s.endswith('"'):
        return s.strip('"').replace('""', '"')
    return s


def replace_special_values(s, **mapping):
    for name, value in mapping.iteritems():
        s = s.replace('$' + name, value)
    return s


class LoggingCursor(cursor):
    def execute(self, sql, args=None):
        if logger.isEnabledFor(logging.DEBUG):
            logger.debug(self.mogrify(sql, args))
        cursor.execute(self, sql, args)


class Database(DatabaseInterface):

    _lock = RLock()
    _databases = {}
    _connpool = None
    _list_cache = None
    _list_cache_timestamp = None
    _version_cache = {}
    _search_path = None
    _current_user = None
    _has_returning = None
    flavor = Flavor(ilike=True)

    TYPES_MAPPING = {
        'INTEGER': SQLType('INT4', 'INT4'),
        'BIGINT': SQLType('INT8', 'INT8'),
        'FLOAT': SQLType('FLOAT8', 'FLOAT8'),
        'BLOB': SQLType('BYTEA', 'BYTEA'),
        'DATETIME': SQLType('TIMESTAMP', 'TIMESTAMP(0)'),
        'TIMESTAMP': SQLType('TIMESTAMP', 'TIMESTAMP(6)'),
        }

    def __new__(cls, name='template1'):
        with cls._lock:
            if name in cls._databases:
                return cls._databases[name]
            inst = DatabaseInterface.__new__(cls, name=name)
            cls._databases[name] = inst

            logger.info('connect to "%s"', name)
            minconn = config.getint('database', 'minconn', default=1)
            maxconn = config.getint('database', 'maxconn', default=64)
            inst._connpool = ThreadedConnectionPool(
                minconn, maxconn, cls.dsn(name),
                cursor_factory=LoggingCursor)

            return inst

    @classmethod
    def dsn(cls, name):
        uri = parse_uri(config.get('database', 'uri'))
        host = uri.hostname and "host=%s" % uri.hostname or ''
        port = uri.port and "port=%s" % uri.port or ''
        name = "dbname=%s" % name
        user = uri.username and "user=%s" % uri.username or ''
        password = ("password=%s" % urllib.unquote_plus(uri.password)
            if uri.password else '')
        return '%s %s %s %s %s' % (host, port, name, user, password)

    def connect(self):
        return self

    def get_connection(self, autocommit=False, readonly=False):
        for count in range(config.getint('database', 'retry'), -1, -1):
            try:
                conn = self._connpool.getconn()
                break
            except PoolError:
                if count and not self._connpool.closed:
                    logger.info('waiting a connection')
                    time.sleep(1)
                    continue
                raise
        if autocommit:
            conn.set_isolation_level(ISOLATION_LEVEL_AUTOCOMMIT)
        else:
            conn.set_isolation_level(ISOLATION_LEVEL_REPEATABLE_READ)
        if readonly:
            cursor = conn.cursor()
            cursor.execute('SET TRANSACTION READ ONLY')
        return conn

    def put_connection(self, connection, close=False):
        self._connpool.putconn(connection, close=close)

    def close(self):
        with self._lock:
            self._connpool.closeall()
            self._databases.pop(self.name)

    @classmethod
    def create(cls, connection, database_name):
        cursor = connection.cursor()
        cursor.execute('CREATE DATABASE "' + database_name + '" '
            'TEMPLATE template0 ENCODING \'unicode\'')
        connection.commit()
        cls._list_cache = None

    def drop(self, connection, database_name):
        cursor = connection.cursor()
        cursor.execute('DROP DATABASE "' + database_name + '"')
        self.__class__._list_cache = None

    def get_version(self, connection):
        if self.name not in self._version_cache:
            cursor = connection.cursor()
            cursor.execute('SELECT version()')
            version, = cursor.fetchone()
            self._version_cache[self.name] = tuple(map(int,
                RE_VERSION.search(version).groups()))
        return self._version_cache[self.name]

    def list(self):
        now = time.time()
        timeout = config.getint('session', 'timeout')
        res = self.__class__._list_cache
        if res and abs(self.__class__._list_cache_timestamp - now) < timeout:
            return res

        connection = self.get_connection()
        cursor = connection.cursor()
        cursor.execute('SELECT datname FROM pg_database '
            'WHERE datistemplate = false ORDER BY datname')
        res = []
        for db_name, in cursor:
            try:
                with connect(self.dsn(db_name)) as conn:
                    if self._test(conn):
                        res.append(db_name)
            except Exception:
                continue
        self.put_connection(connection)

        self.__class__._list_cache = res
        self.__class__._list_cache_timestamp = now
        return res

    def init(self):
        from trytond.modules import get_module_info

        connection = self.get_connection()
        cursor = connection.cursor()
        sql_file = os.path.join(os.path.dirname(__file__), 'init.sql')
        with open(sql_file) as fp:
            for line in fp.read().split(';'):
                if (len(line) > 0) and (not line.isspace()):
                    cursor.execute(line)

        for module in ('ir', 'res'):
            state = 'not activated'
            if module in ('ir', 'res'):
                state = 'to activate'
            info = get_module_info(module)
            cursor.execute('SELECT NEXTVAL(\'ir_module_id_seq\')')
            module_id = cursor.fetchone()[0]
            cursor.execute('INSERT INTO ir_module '
                '(id, create_uid, create_date, name, state) '
                'VALUES (%s, %s, now(), %s, %s)',
                (module_id, 0, module, state))
            for dependency in info.get('depends', []):
                cursor.execute('INSERT INTO ir_module_dependency '
                    '(create_uid, create_date, module, name) '
                    'VALUES (%s, now(), %s, %s)',
                    (0, module_id, dependency))

        connection.commit()
        self.put_connection(connection)

    def test(self):
        connection = self.get_connection()
        is_tryton_database = self._test(connection)
        self.put_connection(connection)
        return is_tryton_database

    @classmethod
    def _test(cls, connection):
        cursor = connection.cursor()
        cursor.execute('SELECT 1 FROM information_schema.tables '
            'WHERE table_name IN %s',
            (('ir_model', 'ir_model_field', 'ir_ui_view', 'ir_ui_menu',
                    'res_user', 'res_group', 'ir_module',
                    'ir_module_dependency', 'ir_translation',
                    'ir_lang'),))
        return len(cursor.fetchall()) != 0

    def nextid(self, connection, table):
        cursor = connection.cursor()
        cursor.execute("SELECT NEXTVAL('" + table + "_id_seq')")
        return cursor.fetchone()[0]

    def setnextid(self, connection, table, value):
        cursor = connection.cursor()
        cursor.execute("SELECT SETVAL('" + table + "_id_seq', %d)" % value)

    def currid(self, connection, table):
        cursor = connection.cursor()
        cursor.execute('SELECT last_value FROM "' + table + '_id_seq"')
        return cursor.fetchone()[0]

    def lock(self, connection, table):
        cursor = connection.cursor()
        cursor.execute('LOCK "%s" IN EXCLUSIVE MODE NOWAIT' % table)

    def has_constraint(self):
        return True

    def has_multirow_insert(self):
        return True

    def get_table_schema(self, connection, table_name):
        cursor = connection.cursor()
        for schema in self.search_path:
            cursor.execute('SELECT 1 '
                'FROM information_schema.tables '
                'WHERE table_name = %s AND table_schema = %s',
                (table_name, schema))
            if cursor.rowcount:
                return schema

    @property
    def current_user(self):
        if self._current_user is None:
            connection = self.get_connection()
            try:
                cursor = connection.cursor()
                cursor.execute('SELECT current_user')
                self._current_user = cursor.fetchone()[0]
            finally:
                self.put_connection(connection)
        return self._current_user

    @property
    def search_path(self):
        if self._search_path is None:
            connection = self.get_connection()
            try:
                cursor = connection.cursor()
                cursor.execute('SHOW search_path')
                path, = cursor.fetchone()
                special_values = {
                    'user': self.current_user,
                }
                self._search_path = [
                    unescape_quote(replace_special_values(
                            p.strip(), **special_values))
                    for p in path.split(',')]
            finally:
                self.put_connection(connection)
        return self._search_path

    def has_returning(self):
        if self._has_returning is None:
            connection = self.get_connection()
            try:
                # RETURNING clause is available since PostgreSQL 8.2
                self._has_returning = self.get_version(connection) >= (8, 2)
            finally:
                self.put_connection(connection)
        return self._has_returning

    def has_select_for(self):
        return True

    def has_window_functions(self):
        return True

    def sql_type(self, type_):
        if type_ in self.TYPES_MAPPING:
            return self.TYPES_MAPPING[type_]
        if type_.startswith('VARCHAR'):
            return SQLType('VARCHAR', type_)
        return SQLType(type_, type_)

    def sql_format(self, type_, value):
        if type_ == 'BLOB':
            if value is not None:
                return Binary(value)
        return value

register_type(UNICODE)
if PYDATE:
    register_type(PYDATE)
if PYDATETIME:
    register_type(PYDATETIME)
if PYTIME:
    register_type(PYTIME)
if PYINTERVAL:
    register_type(PYINTERVAL)
register_adapter(float, lambda value: AsIs(repr(value)))
register_adapter(Decimal, lambda value: AsIs(str(value)))


def convert_json(value):
    return json.loads(value, object_hook=JSONDecoder())
register_default_json(loads=convert_json)
register_default_jsonb(loads=convert_json)