/*
Copyright 2012 The Camlistore Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package postgres

const requiredSchemaVersion = 1

func SchemaVersion() int {
	return requiredSchemaVersion
}

// TODO(mpl): use hstore
func SQLCreateTables() []string {
	return []string{
		`CREATE TABLE rows (
 k VARCHAR(255) NOT NULL PRIMARY KEY,
 v VARCHAR(255))`,

		`CREATE TABLE meta (
 metakey VARCHAR(255) NOT NULL PRIMARY KEY,
 value VARCHAR(255) NOT NULL)`,
	}
}

func SQLDefineReplace() []string {
	return []string{
		`CREATE LANGUAGE plpgsql`,

		`CREATE OR REPLACE FUNCTION replaceinto(key TEXT, value TEXT) RETURNS VOID AS
$$
BEGIN
    LOOP
        UPDATE rows SET v = value WHERE k = key;
        IF found THEN
            RETURN;
        END IF;
        BEGIN
            INSERT INTO rows(k,v) VALUES (key, value);
            RETURN;
        EXCEPTION WHEN unique_violation THEN
        END;
    END LOOP;
END;
$$
LANGUAGE plpgsql;`,
		`CREATE OR REPLACE FUNCTION replaceintometa(key TEXT, val TEXT) RETURNS VOID AS
$$
BEGIN
    LOOP
        UPDATE meta SET value = val WHERE metakey = key;
        IF found THEN
            RETURN;
        END IF;
        BEGIN
            INSERT INTO meta(metakey,value) VALUES (key, val);
            RETURN;
        EXCEPTION WHEN unique_violation THEN
        END;
    END LOOP;
END;
$$
LANGUAGE plpgsql;`,
	}
}