import psycopg2
import yaml
import os


def __run__(params):
    conn = None
    try:
        os.environ['PGPASSFILE'] = params.get('pgpassfile')
        thresolds = yaml.load(params.get('thresholds'))
        conn = psycopg2.connect(host=params.get('host'),
                port=int(params.get('port')),
                database=params.get('dbname'),
                user=params.get('user'))
        cursor = conn.cursor()
        # we connected, so posgtres is working, now some additional tests

        # get number of connections
        cursor.execute("select count(1) from pg_stat_activity")
        current_connections = cursor.fetchone()[0]
        cursor.execute("""select name, setting 
                            from pg_settings 
                           where name = 'max_connections'""")

        max_connections = cursor.fetchone()[1]

        percent = float(current_connections) / float(max_connections)
        percent = percent * 100

        if percent > thresolds['critical']:
            return [2, 'CRITICAL: {0}% of connections in use'.format(percent)]
        elif percent > thresolds['warning']:
            return [1, 'WARNING: {0}% of connections in use'.format(percent)]
        else:
            return [0, 'OK: {0}% of connections in use'.format(percent)]
    except Exception, e:
        return [2, 'CRITICAL: {0}'.format(str(e).replace('\n', ' '))]
    finally:
        try:
            if conn:
                conn.close()
        except:
            # finally clause, don't bother about errors here
            pass