/*
 *  Snapshot maker function.
 */
CREATE FUNCTION snapshot_maker(
    p_src_table text
    , p_dblink_id int
    , p_dest_table text DEFAULT NULL
    , p_index boolean DEFAULT true
    , p_filter text[] DEFAULT NULL
    , p_condition text DEFAULT NULL
    , p_pulldata boolean DEFAULT true
    , p_debug boolean DEFAULT false) 
RETURNS void
    LANGUAGE plpgsql
    AS $$
DECLARE

v_data_source               text;
v_insert_refresh_config     text;
v_jobmon                    boolean;

BEGIN

SELECT data_source INTO v_data_source FROM @extschema@.dblink_mapping WHERE data_source_id = p_dblink_id; 
IF NOT FOUND THEN
	RAISE EXCEPTION 'ERROR: Database link ID does not exist in @extschema@.dblink_mapping: %', p_dblink_id; 
END IF;  

IF p_dest_table IS NULL THEN
    p_dest_table := p_src_table;
END IF;

IF position('.' in p_dest_table) = 0 AND position('.' in p_src_table) = 0 THEN
    RAISE EXCEPTION 'Source (and destination) table must be schema qualified';
END IF;

-- Determine if pg_jobmon is installed to set config table option below
SELECT 
    CASE 
        WHEN count(nspname) > 0 THEN true
        ELSE false
    END AS jobmon_schema
INTO v_jobmon 
FROM pg_namespace n, pg_extension e WHERE e.extname = 'pg_jobmon' AND e.extnamespace = n.oid;

v_insert_refresh_config := 'INSERT INTO @extschema@.refresh_config_snap(
        source_table
        , dest_table
        , dblink
        , filter
        , condition
        , jobmon) 
    VALUES('
        ||quote_literal(p_src_table)
        ||', '||quote_literal(p_dest_table)
        ||', '||p_dblink_id
        ||', '||COALESCE(quote_literal(p_filter), 'NULL')
        ||', '||COALESCE(quote_literal(p_condition), 'NULL')
        ||', '||v_jobmon||')';

EXECUTE v_insert_refresh_config;	

RAISE NOTICE 'attempting first snapshot';
EXECUTE 'SELECT @extschema@.refresh_snap('||quote_literal(p_dest_table)||', p_index := '||p_index||', p_pulldata := '||p_pulldata||', p_debug := '||p_debug||')'; 

RAISE NOTICE 'attempting second snapshot';
EXECUTE 'SELECT @extschema@.refresh_snap('||quote_literal(p_dest_table)||', p_index := '||p_index||', p_pulldata := '||p_pulldata||', p_debug := '||p_debug||')';

RAISE NOTICE 'Done';

RETURN;
END
$$;
