CREATE TYPE cdb_dataservices_client.ds_fdw_metadata as (schemaname text, tabname text, servername text);
CREATE TYPE cdb_dataservices_client.ds_return_metadata as (colnames text[], coltypes text[]);

CREATE OR REPLACE FUNCTION cdb_dataservices_client._OBS_GetTable(table_name text, output_table_name text, function_name text, params json)
RETURNS boolean AS $$
DECLARE
  username text;
  user_db_role text;
  orgname text;
  dbname text;
  user_schema text;
  result boolean;
BEGIN
  IF session_user = 'publicuser' OR session_user ~ 'cartodb_publicuser_*' THEN
    RAISE EXCEPTION 'The api_key must be provided';
  END IF;

  SELECT session_user INTO user_db_role;

  SELECT u, o INTO username, orgname FROM cdb_dataservices_client._cdb_entity_config() AS (u text, o text);
  -- JSON value stored "" is taken as literal
  IF username IS NULL OR username = '' OR username = '""' THEN
    RAISE EXCEPTION 'Username is a mandatory argument';
  END IF;

  IF orgname IS NULL OR orgname = '' OR orgname = '""' THEN
    user_schema := 'public';
  ELSE
    user_schema := username;
  END IF;

  SELECT current_database() INTO dbname;

  SELECT cdb_dataservices_client.__OBS_GetTable(username, orgname, user_db_role, user_schema, dbname, table_name, output_table_name, function_name, params) INTO result;

  RETURN result;
END;
$$ LANGUAGE 'plpgsql' SECURITY DEFINER;


CREATE OR REPLACE FUNCTION cdb_dataservices_client._OBS_AugmentTable(table_name text, function_name text, params json)
RETURNS boolean AS $$
DECLARE
  username text;
  user_db_role text;
  orgname text;
  dbname text;
  user_schema text;
  result boolean;
BEGIN
  IF session_user = 'publicuser' OR session_user ~ 'cartodb_publicuser_*' THEN
    RAISE EXCEPTION 'The api_key must be provided';
  END IF;

  SELECT session_user INTO user_db_role;

  SELECT u, o INTO username, orgname FROM cdb_dataservices_client._cdb_entity_config() AS (u text, o text);
  -- JSON value stored "" is taken as literal
  IF username IS NULL OR username = '' OR username = '""' THEN
    RAISE EXCEPTION 'Username is a mandatory argument';
  END IF;

  IF orgname IS NULL OR orgname = '' OR orgname = '""' THEN
    user_schema := 'public';
  ELSE
    user_schema := username;
  END IF;

  SELECT current_database() INTO dbname;

  SELECT cdb_dataservices_client.__OBS_AugmentTable(username, orgname, user_db_role, user_schema, dbname, table_name, function_name, params) INTO result;

  RETURN result;
END;
$$ LANGUAGE 'plpgsql' SECURITY DEFINER;

CREATE OR REPLACE FUNCTION cdb_dataservices_client.__OBS_AugmentTable(username text, orgname text, user_db_role text, user_schema text, dbname text, table_name text, function_name text, params json)
RETURNS boolean AS $$
    from time import strftime
    try:
        server_table_name = None
        temporary_table_name = 'ds_tmp_' + str(strftime("%s")) + table_name

        # Obtain return types for augmentation procedure
        ds_return_metadata = plpy.execute("SELECT colnames, coltypes "
            "FROM cdb_dataservices_client._OBS_GetReturnMetadata({username}::text, {orgname}::text, {function_name}::text, {params}::json);"
            .format(username=plpy.quote_nullable(username), orgname=plpy.quote_nullable(orgname), function_name=plpy.quote_literal(function_name), params=plpy.quote_literal(params))
            )

        colnames_arr = ds_return_metadata[0]["colnames"]
        coltypes_arr = ds_return_metadata[0]["coltypes"]

        # Prepare column and type strings required in the SQL queries
        colnames = ','.join(colnames_arr)
        columns_with_types_arr = [colnames_arr[i] + ' ' + coltypes_arr[i] for i in range(0,len(colnames_arr))]
        columns_with_types = ','.join(columns_with_types_arr)


        # Instruct the OBS server side to establish a FDW
        # The metadata is obtained as well in order to:
        #   - (a) be able to write the query to grab the actual data to be executed in the remote server via pl/proxy,
        #   - (b) be able to tell OBS to free resources when done.
        ds_fdw_metadata = plpy.execute("SELECT schemaname, tabname, servername "
            "FROM cdb_dataservices_client._OBS_ConnectUserTable({username}::text, {orgname}::text, {user_db_role}::text, {user_schema}::text, {dbname}::text, {table_name}::text);"
            .format(username=plpy.quote_nullable(username), orgname=plpy.quote_nullable(orgname), user_db_role=plpy.quote_literal(user_db_role), user_schema=plpy.quote_literal(user_schema), dbname=plpy.quote_literal(dbname), table_name=plpy.quote_literal(table_name))
            )

        server_schema = ds_fdw_metadata[0]["schemaname"]
        server_table_name = ds_fdw_metadata[0]["tabname"]
        server_name = ds_fdw_metadata[0]["servername"]

        # Create temporary table with the augmented results
        plpy.execute('CREATE UNLOGGED TABLE "{user_schema}".{temp_table_name} AS '
            '(SELECT {columns}, cartodb_id '
            'FROM cdb_dataservices_client._OBS_FetchJoinFdwTableData('
            '{username}::text, {orgname}::text, {schema}::text, {table_name}::text, {function_name}::text, {params}::json) '
            'AS results({columns_with_types}, cartodb_id int) )'
            .format(columns=colnames, username=plpy.quote_nullable(username), orgname=plpy.quote_nullable(orgname),
                user_schema=user_schema, schema=plpy.quote_literal(server_schema), table_name=plpy.quote_literal(server_table_name),
                function_name=plpy.quote_literal(function_name), params=plpy.quote_literal(params), columns_with_types=columns_with_types,
                temp_table_name=temporary_table_name)
            )

        # Wipe user FDW data from the server
        wiped = plpy.execute("SELECT cdb_dataservices_client._OBS_DisconnectUserTable({username}::text, {orgname}::text, {server_schema}::text, {server_table_name}::text, {fdw_server}::text)"
            .format(username=plpy.quote_nullable(username), orgname=plpy.quote_nullable(orgname), server_schema=plpy.quote_literal(server_schema), server_table_name=plpy.quote_literal(server_table_name), fdw_server=plpy.quote_literal(server_name))
            )

        # Prepare table to receive augmented results in new columns
        for idx, column in enumerate(colnames_arr):
            if colnames_arr[idx] is not 'the_geom':
                plpy.execute('ALTER TABLE "{user_schema}".{table_name} ADD COLUMN {column_name} {column_type}'
                    .format(user_schema=user_schema, table_name=table_name, column_name=colnames_arr[idx], column_type=coltypes_arr[idx])
                    )

        # Populate the user table with the augmented results
        plpy.execute('UPDATE "{user_schema}".{table_name} SET {columns} = '
            '(SELECT {columns} FROM "{user_schema}".{temporary_table_name} '
            'WHERE "{user_schema}".{temporary_table_name}.cartodb_id = "{user_schema}".{table_name}.cartodb_id)'
            .format(columns = colnames, username=plpy.quote_nullable(username), orgname=plpy.quote_nullable(orgname),
                user_schema = user_schema, table_name=table_name, function_name=function_name, params=params, columns_with_types=columns_with_types,
                temporary_table_name=temporary_table_name)
            )

        plpy.execute('DROP TABLE IF EXISTS "{user_schema}".{temporary_table_name}'
            .format(user_schema=user_schema, table_name=table_name, temporary_table_name=temporary_table_name)
            )

        return True
    except Exception as e:
        plpy.warning('Error trying to augment table {0}'.format(e))
        # Wipe user FDW data from the server in case of failure if the table was connected
        if server_table_name:
            # Wipe local temporary table
            plpy.execute('DROP TABLE IF EXISTS "{user_schema}".{temporary_table_name}'
                .format(user_schema=user_schema, table_name=table_name, temporary_table_name=temporary_table_name)
                )

            wiped = plpy.execute("SELECT cdb_dataservices_client._OBS_DisconnectUserTable({username}::text, {orgname}::text, {server_schema}::text, {server_table_name}::text, {fdw_server}::text)"
                .format(username=plpy.quote_nullable(username), orgname=plpy.quote_nullable(orgname), server_schema=plpy.quote_literal(server_schema), server_table_name=plpy.quote_literal(server_table_name), fdw_server=plpy.quote_literal(server_name))
                )
        return False
$$ LANGUAGE plpythonu;



CREATE OR REPLACE FUNCTION cdb_dataservices_client.__OBS_GetTable(username text, orgname text, user_db_role text, user_schema text, dbname text, table_name text, output_table_name text, function_name text, params json)
RETURNS boolean AS $$
    try:
        server_table_name = None
        # Obtain return types for augmentation procedure
        ds_return_metadata = plpy.execute("SELECT colnames, coltypes "
            "FROM cdb_dataservices_client._OBS_GetReturnMetadata({username}::text, {orgname}::text, {function_name}::text, {params}::json);"
            .format(username=plpy.quote_nullable(username), orgname=plpy.quote_nullable(orgname), function_name=plpy.quote_literal(function_name), params=plpy.quote_literal(params))
            )

        colnames_arr = ds_return_metadata[0]["colnames"]
        coltypes_arr = ds_return_metadata[0]["coltypes"]

        # Prepare column and type strings required in the SQL queries
        colnames = ','.join(colnames_arr)
        columns_with_types_arr = [colnames_arr[i] + ' ' + coltypes_arr[i] for i in range(0,len(colnames_arr))]
        columns_with_types = ','.join(columns_with_types_arr)


        # Instruct the OBS server side to establish a FDW
        # The metadata is obtained as well in order to:
        #   - (a) be able to write the query to grab the actual data to be executed in the remote server via pl/proxy,
        #   - (b) be able to tell OBS to free resources when done.
        ds_fdw_metadata = plpy.execute("SELECT schemaname, tabname, servername "
            "FROM cdb_dataservices_client._OBS_ConnectUserTable({username}::text, {orgname}::text, {user_db_role}::text, {schema}::text, {dbname}::text, {table_name}::text);"
            .format(username=plpy.quote_nullable(username), orgname=plpy.quote_nullable(orgname), user_db_role=plpy.quote_literal(user_db_role), schema=plpy.quote_literal(user_schema), dbname=plpy.quote_literal(dbname), table_name=plpy.quote_literal(table_name))
            )

        server_schema = ds_fdw_metadata[0]["schemaname"]
        server_table_name = ds_fdw_metadata[0]["tabname"]
        server_name = ds_fdw_metadata[0]["servername"]

        # Get list of user columns to include in the new table
        user_table_columns = ','.join(
            plpy.execute('SELECT array_agg(\'user_table.\' || attname) AS columns '
                'FROM pg_attribute WHERE attrelid = \'"{user_schema}".{table_name}\'::regclass '
                'AND attnum > 0 AND NOT attisdropped AND attname NOT LIKE \'the_geom_webmercator\' '
                'AND NOT attname LIKE ANY(string_to_array(\'{colnames}\',\',\'));'
                .format(user_schema=user_schema, table_name=table_name, colnames=colnames)
                )[0]["columns"]
        )

        # Populate a new table with the augmented results
        plpy.execute('CREATE TABLE "{user_schema}".{output_table_name} AS '
            '(SELECT results.{columns}, {user_table_columns} '
            'FROM {table_name} AS user_table '
            'LEFT JOIN cdb_dataservices_client._OBS_FetchJoinFdwTableData({username}::text, {orgname}::text, {server_schema}::text, {server_table_name}::text, {function_name}::text, {params}::json) as results({columns_with_types}, cartodb_id int) '
            'ON results.cartodb_id = user_table.cartodb_id)'
            .format(output_table_name=output_table_name, columns=colnames, user_table_columns=user_table_columns, username=plpy.quote_nullable(username),
                orgname=plpy.quote_nullable(orgname), user_schema=user_schema, server_schema=plpy.quote_literal(server_schema), server_table_name=plpy.quote_literal(server_table_name),
                table_name=table_name, function_name=plpy.quote_literal(function_name), params=plpy.quote_literal(params), columns_with_types=columns_with_types)
            )

        plpy.execute('ALTER TABLE "{schema}".{table_name} OWNER TO "{user}";'
            .format(schema=user_schema, table_name=output_table_name, user=user_db_role)
            )

        # Wipe user FDW data from the server
        wiped = plpy.execute("SELECT cdb_dataservices_client._OBS_DisconnectUserTable({username}::text, {orgname}::text, {server_schema}::text, {server_table_name}::text, {fdw_server}::text)"
            .format(username=plpy.quote_nullable(username), orgname=plpy.quote_nullable(orgname), server_schema=plpy.quote_literal(server_schema), server_table_name=plpy.quote_literal(server_table_name), fdw_server=plpy.quote_literal(server_name))
            )

        return True
    except Exception as e:
        plpy.warning('Error trying to get table {0}'.format(e))
        # Wipe user FDW data from the server in case of failure if the table was connected
        if server_table_name:
            wiped = plpy.execute("SELECT cdb_dataservices_client._OBS_DisconnectUserTable({username}::text, {orgname}::text, {server_schema}::text, {server_table_name}::text, {fdw_server}::text)"
                .format(username=plpy.quote_nullable(username), orgname=plpy.quote_nullable(orgname), server_schema=plpy.quote_literal(server_schema), server_table_name=plpy.quote_literal(server_table_name), fdw_server=plpy.quote_literal(server_name))
                )
        return False
$$ LANGUAGE plpythonu;


CREATE OR REPLACE FUNCTION cdb_dataservices_client._OBS_ConnectUserTable(username text, orgname text, user_db_role text, user_schema text, dbname text, table_name text)
RETURNS cdb_dataservices_client.ds_fdw_metadata AS $$
    CONNECT _server_conn_str();
    TARGET cdb_dataservices_server._OBS_ConnectUserTable;
$$ LANGUAGE plproxy;

CREATE OR REPLACE FUNCTION cdb_dataservices_client._OBS_GetReturnMetadata(username text, orgname text, function_name text, params json)
RETURNS cdb_dataservices_client.ds_return_metadata AS $$
    CONNECT _server_conn_str();
    TARGET cdb_dataservices_server._OBS_GetReturnMetadata;
$$ LANGUAGE plproxy;

CREATE OR REPLACE FUNCTION cdb_dataservices_client._OBS_FetchJoinFdwTableData(username text, orgname text, table_schema text, table_name text, function_name text, params json)
RETURNS SETOF record AS $$
    CONNECT _server_conn_str();
    TARGET cdb_dataservices_server._OBS_FetchJoinFdwTableData;
$$ LANGUAGE plproxy;

CREATE OR REPLACE FUNCTION cdb_dataservices_client._OBS_DisconnectUserTable(username text, orgname text, table_schema text, table_name text, server_name text)
RETURNS boolean AS $$
    CONNECT _server_conn_str();
    TARGET cdb_dataservices_server._OBS_DisconnectUserTable;
$$ LANGUAGE plproxy;
