-- Allow inserter, updater, dml & logdel maker functions to handle the destination table already existing. In that case, the destination table will not be touched and no data will be pulled from the source. For inserter & updater, the last_value function will either be given the max value of the current destination data or the timestamp at the time the maker function runs.
-- Updated documentation
-- Some code cleanup for simplification & clarity


/*
 *  DML maker function.
 */
CREATE OR REPLACE FUNCTION dml_maker(p_src_table text, p_dblink_id int, p_pk_field text[], p_pk_type text[], p_dest_table text DEFAULT NULL) RETURNS void
    LANGUAGE plpgsql
    AS $$
DECLARE

v_conns                     text[];
v_create_trig               text;
v_dblink_schema             text;
v_dest_check                text;
v_dest_schema_name          text;
v_dest_table_name           text;
v_insert_refresh_config     text;
v_old_search_path           text;
v_pk_counter                int := 1;
v_pk_field_csv              text := '';
v_pk_field_type_csv         text := '';
v_remote_q_index            text;
v_remote_q_table            text;
v_src_table_name            text;
v_trigger_func              text;


BEGIN

SELECT nspname INTO v_dblink_schema FROM pg_namespace n, pg_extension e WHERE e.extname = 'dblink' AND e.extnamespace = n.oid;

-- Set custom search path to allow easier calls to other functions
SELECT current_setting('search_path') INTO v_old_search_path;
EXECUTE 'SELECT set_config(''search_path'',''@extschema@,'||v_dblink_schema||',public'',''false'')';

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

IF position('.' in p_src_table) > 0 THEN
    v_src_table_name := split_part(p_src_table, '.', 2);
END IF;

IF position('.' in p_dest_table) > 0 THEN
    v_dest_schema_name := split_part(p_dest_table, '.', 1); 
    v_dest_table_name := split_part(p_dest_table, '.', 2);
END IF;

v_remote_q_table := 'CREATE TABLE @extschema@.'||v_src_table_name||'_pgq (';

v_pk_field_csv := array_to_string(p_pk_field, ',');
WHILE v_pk_counter <= array_length(p_pk_field,1) LOOP
    IF v_pk_counter > 1 THEN
        v_pk_field_type_csv := v_pk_field_type_csv || ', ';
    END IF;
    v_pk_field_type_csv := v_pk_field_type_csv ||p_pk_field[v_pk_counter]||' '||p_pk_type[v_pk_counter];
    v_pk_counter := v_pk_counter + 1;
END LOOP;

v_remote_q_table := v_remote_q_table || v_pk_field_type_csv || ', processed boolean)';

v_remote_q_index := 'CREATE INDEX ON @extschema@.'||v_src_table_name||'_pgq ('||v_pk_field_csv||')';

v_pk_counter := 1;
v_trigger_func := 'CREATE FUNCTION @extschema@.'||v_src_table_name||'_mimeo_queue() RETURNS trigger LANGUAGE plpgsql AS $_$ DECLARE ';
    WHILE v_pk_counter <= array_length(p_pk_field,1) LOOP
        v_trigger_func := v_trigger_func||'v_'||p_pk_field[v_pk_counter]||' '||p_pk_type[v_pk_counter]||'; ';
        v_pk_counter := v_pk_counter + 1;
    END LOOP;
    v_pk_counter := 1;
    v_trigger_func := v_trigger_func || ' BEGIN IF TG_OP = ''INSERT'' THEN ';
    WHILE v_pk_counter <= array_length(p_pk_field,1) LOOP
        v_trigger_func := v_trigger_func||' v_'||p_pk_field[v_pk_counter]||' := NEW.'||p_pk_field[v_pk_counter]||'; ';
        v_pk_counter := v_pk_counter + 1;
    END LOOP;
    v_pk_counter := 1;
    v_trigger_func := v_trigger_func || ' ELSE ';
    WHILE v_pk_counter <= array_length(p_pk_field,1) LOOP
        v_trigger_func := v_trigger_func||' v_'||p_pk_field[v_pk_counter]||' := OLD.'||p_pk_field[v_pk_counter]||'; ';
        v_pk_counter := v_pk_counter + 1;
    END LOOP;
    v_pk_counter := 1;
    v_trigger_func := v_trigger_func || ' END IF; INSERT INTO @extschema@.'||v_src_table_name||'_pgq ('||v_pk_field_csv||') ';
    v_trigger_func := v_trigger_func || ' VALUES (';
    WHILE v_pk_counter <= array_length(p_pk_field,1) LOOP
        IF v_pk_counter > 1 THEN
            v_trigger_func := v_trigger_func || ', ';
        END IF;
        v_trigger_func := v_trigger_func||'v_'||p_pk_field[v_pk_counter];
        v_pk_counter := v_pk_counter + 1;
    END LOOP;
    v_trigger_func := v_trigger_func || '); RETURN NULL; END $_$;';

v_create_trig := 'CREATE TRIGGER '||v_src_table_name||'_mimeo_trig AFTER INSERT OR UPDATE OR DELETE ON '||p_src_table||
    ' FOR EACH ROW EXECUTE PROCEDURE @extschema@.'||v_src_table_name||'_mimeo_queue()';

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

RAISE NOTICE 'Creating objects on source database (function, trigger & queue table)...';
PERFORM dblink_exec('mimeo_dml', v_remote_q_table);
PERFORM dblink_exec('mimeo_dml', v_remote_q_index);
PERFORM dblink_exec('mimeo_dml', v_trigger_func);
PERFORM dblink_exec('mimeo_dml', v_create_trig);

PERFORM dblink_disconnect('mimeo_dml');

-- Only create destination table if it doesn't already exist
SELECT schemaname||'.'||tablename INTO v_dest_check FROM pg_tables WHERE schemaname = v_dest_schema_name AND tablename = v_dest_table_name;
IF v_dest_check IS NULL THEN
    RAISE NOTICE 'Snapshotting source table to pull all current source data...';
    -- Snapshot the table after triggers have been created to ensure all new data after setup is replicated
    v_insert_refresh_config := 'INSERT INTO @extschema@.refresh_config_snap(source_table, dest_table, dblink) VALUES('
        ||quote_literal(p_src_table)||', '||quote_literal(p_dest_table)||', '|| p_dblink_id||')';
    EXECUTE v_insert_refresh_config;

    PERFORM @extschema@.refresh_snap(p_dest_table);
    PERFORM @extschema@.snapshot_destroyer(p_dest_table, 'ARCHIVE');
ELSE
    RAISE NOTICE 'Destination table % already exists. No data was pulled from source', p_dest_table;
END IF;

v_insert_refresh_config := 'INSERT INTO @extschema@.refresh_config_dml(source_table, dest_table, dblink, control, pk_field, pk_type, last_value) VALUES('
    ||quote_literal(p_src_table)||', '||quote_literal(p_dest_table)||', '|| p_dblink_id||', '||quote_literal('@extschema@.'||v_src_table_name||'_pgq')||', '
    ||quote_literal(p_pk_field)||', '||quote_literal(p_pk_type)||', '||quote_literal(clock_timestamp())||')';
RAISE NOTICE 'Inserting data into config table';
EXECUTE v_insert_refresh_config;

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

RAISE NOTICE 'Done';

EXCEPTION
    WHEN OTHERS THEN
        EXECUTE 'SELECT set_config(''search_path'',''@extschema@,'||v_dblink_schema||''',''false'')';
        v_conns := dblink_get_connections();
        IF dblink_get_connections() @> '{mimeo_dml}' THEN
            PERFORM dblink_disconnect('mimeo_dml');
        END IF;
        EXECUTE 'SELECT set_config(''search_path'','''||v_old_search_path||''',''false'')';
        RAISE EXCEPTION '%', SQLERRM;    
END
$$;

/*
 *  Logdel maker function.
 */
CREATE OR REPLACE FUNCTION logdel_maker(p_src_table text, p_dblink_id int, p_pk_field text[], p_pk_type text[], p_dest_table text DEFAULT NULL) RETURNS void
    LANGUAGE plpgsql
    AS $$
DECLARE

v_col_exists                int;
v_cols                      text[];
v_cols_csv                  text;
v_cols_n_types              text[];
v_cols_n_types_csv          text;
v_conns                     text[];
v_create_trig               text;
v_dblink_schema             text;
v_dest_check                text;
v_dest_schema_name          text;
v_dest_table_name           text;
v_insert_refresh_config     text;
v_old_search_path           text;
v_counter                   int := 1;
v_pk_field_csv              text := '';
v_pk_field_type_csv         text := '';
v_remote_sql                text;
v_remote_q_index            text;
v_remote_q_table            text;
v_src_table_name            text;
v_trigger_func              text;
v_types                     text[];


BEGIN

SELECT nspname INTO v_dblink_schema FROM pg_namespace n, pg_extension e WHERE e.extname = 'dblink' AND e.extnamespace = n.oid;

-- Set custom search path to allow easier calls to other functions
SELECT current_setting('search_path') INTO v_old_search_path;
EXECUTE 'SELECT set_config(''search_path'',''@extschema@,'||v_dblink_schema||',public'',''false'')';

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

IF position('.' in p_src_table) > 0 THEN
    v_src_table_name := split_part(p_src_table, '.', 2);
END IF;

IF position('.' in p_dest_table) > 0 THEN
    v_dest_schema_name := split_part(p_dest_table, '.', 1); 
    v_dest_table_name := split_part(p_dest_table, '.', 2);
END IF;

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

v_remote_sql := 'SELECT array_agg(attname) as cols, array_agg(atttypid::regtype::text) as types, array_agg(attname||'' ''||atttypid::regtype::text) as cols_n_types FROM pg_attribute WHERE attnum > 0 AND attisdropped is false AND attrelid = ' || quote_literal(p_src_table) || '::regclass';
v_remote_sql := 'SELECT cols, types, cols_n_types FROM dblink(''mimeo_logdel'', ' || quote_literal(v_remote_sql) || ') t (cols text[], types text[], cols_n_types text[])';
EXECUTE v_remote_sql INTO v_cols, v_types, v_cols_n_types;

v_cols_csv := array_to_string(v_cols, ',');
v_cols_n_types_csv := array_to_string(v_cols_n_types, ',');

v_remote_q_table := 'CREATE TABLE @extschema@.'||v_src_table_name||'_pgq ('||v_cols_n_types_csv||', mimeo_source_deleted timestamptz, processed boolean)';

v_pk_field_csv := array_to_string(p_pk_field, ',');
WHILE v_counter <= array_length(p_pk_field,1) LOOP
    IF v_counter > 1 THEN
        v_pk_field_type_csv := v_pk_field_type_csv || ', ';
    END IF;
    v_pk_field_type_csv := v_pk_field_type_csv ||p_pk_field[v_counter]||' '||p_pk_type[v_counter];
    v_counter := v_counter + 1;
END LOOP;

v_remote_q_index := 'CREATE INDEX ON @extschema@.'||v_src_table_name||'_pgq ('||v_pk_field_csv||')';

v_counter := 1;
v_trigger_func := 'CREATE FUNCTION @extschema@.'||v_src_table_name||'_mimeo_queue() RETURNS trigger LANGUAGE plpgsql AS $_$ DECLARE ';
    WHILE v_counter <= array_length(v_cols,1) LOOP
        v_trigger_func := v_trigger_func||'v_'||v_cols[v_counter]||' '||v_types[v_counter]||'; ';
        v_counter := v_counter + 1;
    END LOOP;
    v_trigger_func := v_trigger_func || 'v_del_time timestamptz; ';
    v_counter := 1;
    v_trigger_func := v_trigger_func || ' BEGIN IF TG_OP = ''INSERT'' THEN ';
    WHILE v_counter <= array_length(p_pk_field,1) LOOP
        v_trigger_func := v_trigger_func||' v_'||p_pk_field[v_counter]||' := NEW.'||p_pk_field[v_counter]||'; ';
        v_counter := v_counter + 1;
    END LOOP;
    v_counter := 1;
    v_trigger_func := v_trigger_func || ' ELSIF TG_OP = ''UPDATE'' THEN  ';
    WHILE v_counter <= array_length(p_pk_field,1) LOOP
        v_trigger_func := v_trigger_func||' v_'||p_pk_field[v_counter]||' := OLD.'||p_pk_field[v_counter]||'; ';
        v_counter := v_counter + 1;
    END LOOP;
    v_counter := 1;
    v_trigger_func := v_trigger_func || ' ELSIF TG_OP = ''DELETE'' THEN  ';
    WHILE v_counter <= array_length(v_cols,1) LOOP
        v_trigger_func := v_trigger_func||' v_'||v_cols[v_counter]||' := OLD.'||v_cols[v_counter]||'; ';
        v_counter := v_counter + 1;
    END LOOP;
    v_trigger_func := v_trigger_func || 'v_del_time := clock_timestamp(); ';
    v_counter := 1;
    v_trigger_func := v_trigger_func || ' END IF; INSERT INTO @extschema@.'||v_src_table_name||'_pgq ('||v_cols_csv||', mimeo_source_deleted) ';
    v_trigger_func := v_trigger_func || ' VALUES (';
    WHILE v_counter <= array_length(v_cols,1) LOOP
        IF v_counter > 1 THEN
            v_trigger_func := v_trigger_func || ', ';
        END IF;
        v_trigger_func := v_trigger_func||'v_'||v_cols[v_counter];
        v_counter := v_counter + 1;
    END LOOP;
    v_trigger_func := v_trigger_func ||', v_del_time); RETURN NULL; END $_$;';

v_create_trig := 'CREATE TRIGGER '||v_src_table_name||'_mimeo_trig AFTER INSERT OR UPDATE OR DELETE ON '||p_src_table||
    ' FOR EACH ROW EXECUTE PROCEDURE @extschema@.'||v_src_table_name||'_mimeo_queue()';

RAISE NOTICE 'Creating objects on source database (function, trigger & queue table)...';
PERFORM dblink_exec('mimeo_logdel', v_remote_q_table);
PERFORM dblink_exec('mimeo_logdel', v_remote_q_index);
PERFORM dblink_exec('mimeo_logdel', v_trigger_func);
PERFORM dblink_exec('mimeo_logdel', v_create_trig);

PERFORM dblink_disconnect('mimeo_logdel');

-- Only create destination table if it doesn't already exist
SELECT schemaname||'.'||tablename INTO v_dest_check FROM pg_tables WHERE schemaname = v_dest_schema_name AND tablename = v_dest_table_name;
IF v_dest_check IS NULL THEN
    RAISE NOTICE 'Snapshotting source table to pull all current source data...';
    -- Snapshot the table after triggers have been created to ensure all new data after setup is replicated
    v_insert_refresh_config := 'INSERT INTO @extschema@.refresh_config_snap(source_table, dest_table, dblink) VALUES('
        ||quote_literal(p_src_table)||', '||quote_literal(p_dest_table)||', '|| p_dblink_id||')';

    EXECUTE v_insert_refresh_config;

    PERFORM @extschema@.refresh_snap(p_dest_table);
    PERFORM @extschema@.snapshot_destroyer(p_dest_table, 'ARCHIVE');
ELSE
    RAISE NOTICE 'Destination table % already exists. No data was pulled from source', p_dest_table;
END IF;

SELECT count(*) INTO v_col_exists FROM pg_attribute 
    WHERE attrelid = p_dest_table::regclass AND attname = 'mimeo_source_deleted' AND attisdropped = false;
IF v_col_exists < 1 THEN
    EXECUTE 'ALTER TABLE '||p_dest_table||' ADD COLUMN mimeo_source_deleted timestamptz';
ELSE
    RAISE WARNING 'Special column (mimeo_source_deleted) already exists on destination table (%)', p_dest_table;
END IF;

v_insert_refresh_config := 'INSERT INTO @extschema@.refresh_config_logdel(source_table, dest_table, dblink, control, pk_field, pk_type, last_value) VALUES('
    ||quote_literal(p_src_table)||', '||quote_literal(p_dest_table)||', '|| p_dblink_id||', '||quote_literal('@extschema@.'||v_src_table_name||'_pgq')||', '
    ||quote_literal(p_pk_field)||', '||quote_literal(p_pk_type)||', '||quote_literal(clock_timestamp())||')';
RAISE NOTICE 'Inserting data into config table';

EXECUTE v_insert_refresh_config;

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

RAISE NOTICE 'Done';

EXCEPTION
    WHEN OTHERS THEN
        EXECUTE 'SELECT set_config(''search_path'',''@extschema@,'||v_dblink_schema||''',''false'')';
        v_conns := dblink_get_connections();
        IF dblink_get_connections() @> '{mimeo_logdel}' THEN
            PERFORM dblink_disconnect('mimeo_logdel');
        END IF;
        EXECUTE 'SELECT set_config(''search_path'','''||v_old_search_path||''',''false'')';
        RAISE EXCEPTION '%', SQLERRM;    
END
$$;

/*
 *  Inserter maker function. 
 */
CREATE OR REPLACE FUNCTION inserter_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) RETURNS void
    LANGUAGE plpgsql
    AS $$
DECLARE

v_data_source               text;
v_dest_check                text;
v_dest_schema_name          text;
v_dest_table_name           text;
v_dst_active                boolean;
v_exists                    int;
v_insert_refresh_config     text;
v_max_timestamp             timestamptz;
v_snap_suffix               text;
v_view_definition           text;

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 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 THEN
    v_dest_schema_name := split_part(p_dest_table, '.', 1); 
    v_dest_table_name := split_part(p_dest_table, '.', 2);
END IF;

-- Only create destination table if it doesn't already exist
SELECT schemaname||'.'||tablename INTO v_dest_check FROM pg_tables WHERE schemaname = v_dest_schema_name AND tablename = v_dest_table_name;
IF v_dest_check IS NULL THEN
    v_insert_refresh_config := 'INSERT INTO @extschema@.refresh_config_snap(source_table, dest_table, dblink) VALUES('
        ||quote_literal(p_src_table)||', '||quote_literal(p_dest_table)||', '|| p_dblink_id||')';

    RAISE NOTICE 'Snapshotting source table to pull all current source data...';
    EXECUTE v_insert_refresh_config;	

    PERFORM @extschema@.refresh_snap(p_dest_table);
    PERFORM @extschema@.snapshot_destroyer(p_dest_table, 'ARCHIVE');
	
    RAISE NOTICE 'Snapshot complete.';
ELSE
    RAISE NOTICE 'Destination table % already exists. No data was pulled from source', p_dest_table;
END IF;

RAISE NOTICE 'Getting the maximum destination timestamp...';
EXECUTE 'SELECT max('||p_control_field||') FROM '||p_dest_table||';' INTO v_max_timestamp;

v_dst_active := @extschema@.dst_utc_check();

v_insert_refresh_config := 'INSERT INTO @extschema@.refresh_config_inserter(source_table, dest_table, dblink, control, boundary, last_value, dst_active) 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(COALESCE(v_max_timestamp, CURRENT_TIMESTAMP))||', '||v_dst_active||');';

RAISE NOTICE 'Inserting data into config table';
EXECUTE v_insert_refresh_config;

-- Remove temp snap from config
EXECUTE 'DELETE FROM @extschema@.refresh_config_snap WHERE source_table = '||quote_literal(p_src_table)||' AND dest_table = '||quote_literal(p_dest_table);

RAISE NOTICE 'Done';

RETURN;

END
$$;

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

v_alter_table               text;
v_data_source               text;
v_dest_check                text;
v_dest_schema_name          text;
v_dest_table_name           text;
v_dst_active                boolean;
v_exists                    int;
v_insert_refresh_config     text;
v_max_timestamp             timestamptz;
v_pk_field_csv              text;
v_pk_type_csv               text;
v_snap_suffix               text;
v_update_refresh_config     text;
v_view_definition           text;

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 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 THEN
    v_dest_schema_name := split_part(p_dest_table, '.', 1); 
    v_dest_table_name := split_part(p_dest_table, '.', 2);
END IF;

v_pk_field_csv := array_to_string(p_pk_field,',');
v_pk_type_csv := array_to_string(p_pk_type,',');

-- Only create destination table if it doesn't already exist
SELECT schemaname||'.'||tablename INTO v_dest_check FROM pg_tables WHERE schemaname = v_dest_schema_name AND tablename = v_dest_table_name;
IF v_dest_check IS NULL THEN
    v_insert_refresh_config := 'INSERT INTO @extschema@.refresh_config_snap(source_table, dest_table, dblink) VALUES('
        ||quote_literal(p_src_table)||', '||quote_literal(p_dest_table)||', '|| p_dblink_id||')';

    RAISE NOTICE 'Snapshotting source table to pull all current source data...';
    EXECUTE v_insert_refresh_config;	

    PERFORM @extschema@.refresh_snap(p_dest_table);
    PERFORM @extschema@.snapshot_destroyer(p_dest_table, 'ARCHIVE');

    v_alter_table := 'ALTER TABLE '||p_dest_table||' ADD PRIMARY KEY('||v_pk_field_csv||');';

    RAISE NOTICE 'Snapshot complete. Adding primary key constraint to table..';
    EXECUTE v_alter_table;
    RAISE NOTICE 'Added successfully';
ELSE
    RAISE NOTICE 'Destination table % already exists. No data was pulled from source', p_dest_table;
END IF;

RAISE NOTICE 'Getting the maximum destination timestamp...';
EXECUTE 'SELECT max('||p_control_field||') FROM '||p_dest_table||';' INTO v_max_timestamp;

v_dst_active := @extschema@.dst_utc_check();

v_insert_refresh_config := 'INSERT INTO @extschema@.refresh_config_updater(source_table, dest_table, dblink, control, boundary, pk_field, pk_type, last_value, dst_active) VALUES('
    ||quote_literal(p_src_table)||', '||quote_literal(p_dest_table)||', '|| p_dblink_id||', '||quote_literal(p_control_field)||', '''
    ||p_boundary||'''::interval, '||quote_literal(p_pk_field)||', '||quote_literal(p_pk_type)||', '||quote_literal(COALESCE(v_max_timestamp, CURRENT_TIMESTAMP))||', '||v_dst_active||')';

RAISE NOTICE 'Inserting data into config table';
EXECUTE v_insert_refresh_config;

-- Remove temp snap from config
EXECUTE 'DELETE FROM @extschema@.refresh_config_snap WHERE source_table = '||quote_literal(p_src_table)||' AND dest_table = '||quote_literal(p_dest_table);

RAISE NOTICE 'Done';

RETURN;

END
$$;