"""SQL utilities functions and classes.

:organization: Logilab
:copyright: 2001-2008 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
"""
__docformat__ = "restructuredtext en"

from logilab.common.shellutils import ProgressBar
from logilab.common.db import get_dbapi_compliant_module
from logilab.common.adbh import get_adv_func_helper
from logilab.common.sqlgen import SQLGenerator

from indexer import get_indexer

from cubicweb import Binary, ConfigurationError
from cubicweb.common.uilib import remove_html_tags
from cubicweb.server import SQL_CONNECT_HOOKS
from cubicweb.server.utils import crypt_password, cartesian_product


def sqlexec(sqlstmts, cursor_or_execute, withpb=True, delimiter=';'):
    """execute sql statements ignoring DROP/ CREATE GROUP or USER statements
    error. If a cnx is given, commit at each statement
    """
    if hasattr(cursor_or_execute, 'execute'):
        execute = cursor_or_execute.execute
    else:
        execute = cursor_or_execute
    sqlstmts = sqlstmts.split(delimiter)
    if withpb:
        pb = ProgressBar(len(sqlstmts))
    for sql in sqlstmts:
        sql = sql.strip()
        if withpb:
            pb.update()
        if not sql:
            continue
        # some dbapi modules doesn't accept unicode for sql string
        execute(str(sql))
    if withpb:
        print


def sqlgrants(schema, driver, user,
              text_index=True, set_owner=True,
              skip_relations=(), skip_entities=()):
    """return sql to give all access privileges to the given user on the system
    schema
    """
    from yams.schema2sql import grant_schema
    from cubicweb.server.sources import native
    output = []
    w = output.append
    w(native.grant_schema(user, set_owner))
    w('')
    if text_index:
        indexer = get_indexer(driver)
        w(indexer.sql_grant_user(user))
        w('')
    w(grant_schema(schema, user, set_owner, skip_entities=skip_entities))
    return '\n'.join(output)

                  
def sqlschema(schema, driver, text_index=True, 
              user=None, set_owner=False,
              skip_relations=('has_text', 'identity'), skip_entities=()):
    """return the system sql schema, according to the given parameters"""
    from yams.schema2sql import schema2sql
    from cubicweb.server.sources import native
    if set_owner:
        assert user, 'user is argument required when set_owner is true'
    output = []
    w = output.append
    w(native.sql_schema(driver))
    w('')
    if text_index:
        indexer = get_indexer(driver)
        w(indexer.sql_init_fti())
        w('')
    dbhelper = get_adv_func_helper(driver)
    w(schema2sql(dbhelper, schema, 
                 skip_entities=skip_entities, skip_relations=skip_relations))
    if dbhelper.users_support and user:
        w('')
        w(sqlgrants(schema, driver, user, text_index, set_owner,
                    skip_relations, skip_entities))
    return '\n'.join(output)

                  
def sqldropschema(schema, driver, text_index=True, 
                  skip_relations=('has_text', 'identity'), skip_entities=()):
    """return the sql to drop the schema, according to the given parameters"""
    from yams.schema2sql import dropschema2sql
    from cubicweb.server.sources import native
    output = []
    w = output.append
    w(native.sql_drop_schema(driver))
    w('')
    if text_index:
        indexer = get_indexer(driver)
        w(indexer.sql_drop_fti())
        w('')
    w(dropschema2sql(schema,
                     skip_entities=skip_entities, skip_relations=skip_relations))
    return '\n'.join(output)



class SQLAdapterMixIn(object):
    """Mixin for SQL data sources, getting a connection from a configuration
    dictionary and handling connection locking
    """
    
    def __init__(self, source_config):
        try:
            self.dbdriver = source_config['db-driver'].lower()
            self.dbname = source_config['db-name']
        except KeyError:
            raise ConfigurationError('missing some expected entries in sources file')
        self.dbhost = source_config.get('db-host')
        port = source_config.get('db-port')
        self.dbport = port and int(port) or None
        self.dbuser = source_config.get('db-user')
        self.dbpasswd = source_config.get('db-password')
        self.encoding = source_config.get('db-encoding', 'UTF-8')
        self.dbapi_module = get_dbapi_compliant_module(self.dbdriver)
        self.binary = self.dbapi_module.Binary
        self.dbhelper = self.dbapi_module.adv_func_helper
        self.sqlgen = SQLGenerator()
        
    def get_connection(self, user=None, password=None):
        """open and return a connection to the database"""
        if user or self.dbuser:
            self.info('connecting to %s@%s for user %s', self.dbname,
                      self.dbhost or 'localhost', user or self.dbuser)
        else:
            self.info('connecting to %s@%s', self.dbname,
                      self.dbhost or 'localhost')
        cnx = self.dbapi_module.connect(self.dbhost, self.dbname,
                                        user or self.dbuser,
                                        password or self.dbpasswd,
                                        port=self.dbport)
        init_cnx(self.dbdriver, cnx)
        #self.dbapi_module.type_code_test(cnx.cursor())
        return cnx

    def merge_args(self, args, query_args):
        if args is not None:
            args = dict(args)
            for key, val in args.items():
                # convert cubicweb binary into db binary
                if isinstance(val, Binary):
                    val = self.binary(val.getvalue())
                args[key] = val
            # should not collide
            args.update(query_args)
            return args
        return query_args

    def process_result(self, cursor):
        """return a list of CubicWeb compliant values from data in the given cursor
        """
        descr = cursor.description
        encoding = self.encoding
        process_value = self.dbapi_module.process_value
        binary = Binary
        results = cursor.fetchall()
        for i, line in enumerate(results):
            result = []
            for col, value in enumerate(line):
                if value is None:
                    result.append(value)
                    continue
                result.append(process_value(value, descr[col], encoding, binary))
            results[i] = result
        return results


    def preprocess_entity(self, entity):
        """return a dictionary to use as extra argument to cursor.execute
        to insert/update an entity
        """
        attrs = {}
        eschema = entity.e_schema
        for attr, value in entity.items():
            rschema = eschema.subject_relation(attr)
            if rschema.is_final():
                atype = str(entity.e_schema.destination(attr))
                if atype == 'Boolean':
                    value = self.dbhelper.boolean_value(value)
                elif atype == 'Password':
                    # if value is a Binary instance, this mean we got it
                    # from a query result and so it is already encrypted
                    if isinstance(value, Binary):
                        value = value.getvalue()
                    else:
                        value = crypt_password(value)
                elif isinstance(value, Binary):
                    value = self.binary(value.getvalue())
            attrs[str(attr)] = value
        return attrs


from logging import getLogger
from cubicweb import set_log_methods
set_log_methods(SQLAdapterMixIn, getLogger('cubicweb.sqladapter'))

def init_sqlite_connexion(cnx):
    # XXX should not be publicly exposed
    #def comma_join(strings):
    #    return ', '.join(strings)
    #cnx.create_function("COMMA_JOIN", 1, comma_join)

    class concat_strings(object):
        def __init__(self):
            self.values = []
        def step(self, value):
            if value is not None:
                self.values.append(value)
        def finalize(self):
            return ', '.join(self.values)
    # renamed to GROUP_CONCAT in cubicweb 2.45, keep old name for bw compat for
    # some time
    cnx.create_aggregate("CONCAT_STRINGS", 1, concat_strings)
    cnx.create_aggregate("GROUP_CONCAT", 1, concat_strings)
    
    def _limit_size(text, maxsize, format='text/plain'):
        if len(text) < maxsize:
            return text
        if format in ('text/html', 'text/xhtml', 'text/xml'):
            text = remove_html_tags(text)
        if len(text) > maxsize:
            text = text[:maxsize] + '...'
        return text

    def limit_size3(text, format, maxsize):
        return _limit_size(text, maxsize, format)
    cnx.create_function("LIMIT_SIZE", 3, limit_size3)

    def limit_size2(text, maxsize):
        return _limit_size(text, maxsize)
    cnx.create_function("TEXT_LIMIT_SIZE", 2, limit_size2)
    import yams.constraints
    if hasattr(yams.constraints, 'patch_sqlite_decimal'):
        yams.constraints.patch_sqlite_decimal()


sqlite_hooks = SQL_CONNECT_HOOKS.setdefault('sqlite', [])
sqlite_hooks.append(init_sqlite_connexion)

def init_cnx(driver, cnx):
    for hook in SQL_CONNECT_HOOKS.get(driver, ()):
        hook(cnx)