import sys
import psycopg2

def setDatabase(db_):
    global db
    db = db_
    assert "db" in globals()

def database():
    global db
    assert "db" in globals()
    return db

# Connects to the database and creates a global cursor:
def connectDatabase():
    assert "db" in globals()

    try:
        # ### hardcode for now:
        conn = psycopg2.connect(
            host="bmc.test.qt.nokia.com",
            port="5432",
            database=db,
            user="bmuser")
    except:
        print "failed to connect to the database:", sys.exc_info()
        sys.exit(1)

    global cursor
    cursor = conn.cursor()

# Executes a query against the database. Returns any result set iff
# fetch_results is true.
def execQuery(query, fetch_results = True):
    if not "cursor" in globals():
        connectDatabase()
    assert "cursor" in globals()

    try:
        cursor.execute(query)
        if fetch_results:
            return cursor.fetchall()
    except psycopg2.Error:
        print "query failed: >" + query + "<"
        print "reason:", str(sys.exc_info())
        sys.exit(1)

# Commits everything that has been written to the database.
def commit():
    if not "cursor" in globals():
        return
    cursor.connection.commit()