/*
 *  Updater maker function.
 */ 
CREATE FUNCTION updater_maker(
    p_src_table text
    , p_control_field text
    , p_dblink_id int
    , p_boundary interval DEFAULT '00:10:00'
    , 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_pk_name text[] DEFAULT NULL
    , p_pk_type text[] DEFAULT NULL
    , p_debug boolean DEFAULT false) 
RETURNS void
    LANGUAGE plpgsql
    AS $$
DECLARE

v_data_source               text;
v_dblink_schema             text;
v_dest_schema_name          text;
v_dest_table_name           text;
v_dst_active                boolean;
v_field                     text;
v_insert_refresh_config     text;
v_jobmon                    boolean;
v_key_type                  text;
v_link_exists               boolean;
v_max_timestamp             timestamptz;
v_old_search_path           text;
v_pk_name                   text[] := p_pk_name;
v_pk_type                   text[] := p_pk_type;
v_remote_key_sql            text;
v_table_exists              boolean;
v_update_refresh_config     text;

BEGIN

SELECT nspname INTO v_dblink_schema FROM pg_namespace n, pg_extension e WHERE e.extname = 'dblink' AND e.extnamespace = n.oid;
SELECT current_setting('search_path') INTO v_old_search_path;
EXECUTE 'SELECT set_config(''search_path'',''@extschema@,'||v_dblink_schema||',public'',''false'')';

IF (p_pk_name IS NULL AND p_pk_type IS NOT NULL) OR (p_pk_name IS NOT NULL AND p_pk_type IS NULL) THEN
    RAISE EXCEPTION 'Cannot manually set primary/unique key field(s) without defining type(s) or vice versa';
END IF;

SELECT data_source INTO v_data_source FROM @extschema@.dblink_mapping_mimeo WHERE data_source_id = p_dblink_id; 
IF NOT FOUND THEN
	RAISE EXCEPTION 'ERROR: database link ID is incorrect %', 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
    v_dest_schema_name := split_part(p_dest_table, '.', 1); 
    v_dest_table_name := split_part(p_dest_table, '.', 2);
ELSE
    RAISE EXCEPTION 'Source (and destination) table must be schema qualified';
END IF;

PERFORM dblink_connect('mimeo_updater', @extschema@.auth(p_dblink_id));

-- Automatically get source primary/unique key if none given
IF p_pk_name IS NULL AND p_pk_type IS NULL THEN
    SELECT v_key_type, indkey_names, indkey_types INTO v_key_type, v_pk_name, v_pk_type FROM fetch_replication_key(p_src_table, 'mimeo_updater');
END IF;

IF v_pk_name IS NULL OR v_pk_type IS NULL THEN
    RAISE EXCEPTION 'Source table has no valid primary key or unique index';
END IF;

IF p_filter IS NOT NULL THEN
    FOREACH v_field IN ARRAY v_pk_name LOOP
        IF v_field = ANY(p_filter) THEN
            CONTINUE;
        ELSE
            RAISE EXCEPTION 'ERROR: filter list did not contain all columns that compose primary/unique key for source table %', p_src_table;
        END IF;
    END LOOP;
END IF;

v_dst_active := @extschema@.dst_utc_check();

-- 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_updater(
        source_table
        , dest_table
        , dblink
        , control
        , boundary
        , pk_name
        , pk_type
        , last_value
        , last_run
        , dst_active
        , filter
        , condition
        , jobmon) 
    VALUES('
        ||quote_literal(p_src_table)
        ||', '||quote_literal(p_dest_table)
        ||', '|| p_dblink_id
        ||', '||quote_literal(p_control_field)
        ||', '||quote_literal(p_boundary)
        ||', '||quote_literal(v_pk_name)
        ||', '||quote_literal(v_pk_type)
        ||', ''0001-01-01''::date ,'
              ||quote_literal(CURRENT_TIMESTAMP)
        ||', '||v_dst_active
        ||', '||COALESCE(quote_literal(p_filter), 'NULL')
        ||', '||COALESCE(quote_literal(p_condition), 'NULL')
        ||', '||v_jobmon||')';
PERFORM gdb(p_debug, 'v_insert_refresh_config: '||v_insert_refresh_config);
EXECUTE v_insert_refresh_config;

SELECT p_table_exists FROM @extschema@.manage_dest_table(p_dest_table, NULL, p_debug) INTO v_table_exists;

IF p_pulldata AND v_table_exists = false THEN
    RAISE NOTICE 'Pulling all data from source...';
    EXECUTE 'SELECT @extschema@.refresh_updater('||quote_literal(p_dest_table)||', p_repull := true, p_debug := '||p_debug||')';
END IF;

IF p_index AND v_table_exists = false THEN
    PERFORM create_index(p_dest_table, NULL, p_debug);
ELSIF v_table_exists = false THEN
-- Ensure destination indexes that are needed for efficient replication are created even if p_index is set false
    PERFORM gdb(p_debug, 'Creating indexes needed for replication');
    IF v_key_type = 'primary' THEN
        EXECUTE 'ALTER TABLE '||p_dest_table||' ADD PRIMARY KEY('||array_to_string(v_pk_name, ',')||')';
    ELSE
        EXECUTE 'CREATE UNIQUE INDEX ON '||p_dest_table||' ('||array_to_string(v_pk_name, ',')||')';
    END IF;
END IF;

IF v_table_exists THEN
    RAISE NOTICE 'Destination table % already exists. No data or indexes was pulled from source', p_dest_table;
END IF;

PERFORM dblink_disconnect('mimeo_updater');

RAISE NOTICE 'Getting the maximum destination timestamp...';
EXECUTE 'SELECT max('||p_control_field||') FROM '||p_dest_table||';' INTO v_max_timestamp;
EXECUTE 'UPDATE @extschema@.refresh_config_updater SET last_value = '||quote_literal(COALESCE(v_max_timestamp, CURRENT_TIMESTAMP))||' WHERE dest_table = '||quote_literal(p_dest_table);

EXECUTE 'SELECT set_config(''search_path'','''||v_old_search_path||''',''false'')';

RAISE NOTICE 'Done';

RETURN;

EXCEPTION
    WHEN QUERY_CANCELED OR OTHERS THEN
        EXECUTE 'SELECT '||v_dblink_schema||'.dblink_get_connections() @> ARRAY['||quote_literal(v_dblink_name)||']' INTO v_link_exists;
        IF v_link_exists THEN
            EXECUTE 'SELECT '||v_dblink_schema||'.dblink_disconnect('||quote_literal(v_dblink_name)||')';
        END IF;
        EXECUTE 'SELECT set_config(''search_path'','''||v_old_search_path||''',''false'')';
        RAISE EXCEPTION '%', SQLERRM;   
END  
$$;

