CREATE OR REPLACE FUNCTION {{function_name}}() RETURNS trigger LANGUAGE plpgsql AS $$
  DECLARE r {{table_name}}%ROWTYPE;
  DECLARE conflict_clause jsonb;
  DECLARE action text;
  DECLARE constraint_name text;
  DECLARE set_expression text;
  BEGIN
    conflict_clause = current_setting('hasura.conflict_clause')::jsonb;
    IF ({{check_expression}}) THEN
      CASE
        WHEN conflict_clause = 'null'::jsonb THEN INSERT INTO {{table_name}} VALUES (NEW.*) RETURNING * INTO r;
        ELSE
          action = conflict_clause ->> 'action';
          constraint_name = quote_ident(conflict_clause ->> 'constraint');
          set_expression = conflict_clause ->> 'set_expression';
          IF action is NOT NULL THEN
            CASE
              WHEN action = 'ignore'::text AND constraint_name IS NULL THEN
                INSERT INTO {{table_name}} VALUES (NEW.*) ON CONFLICT DO NOTHING RETURNING * INTO r;
              WHEN action = 'ignore'::text AND constraint_name is NOT NULL THEN
                EXECUTE 'INSERT INTO {{table_name}} VALUES ($1.*) ON CONFLICT ON CONSTRAINT ' || constraint_name ||
                           ' DO NOTHING RETURNING *' INTO r USING NEW;
              ELSE
                EXECUTE 'INSERT INTO {{table_name}} VALUES ($1.*) ON CONFLICT ON CONSTRAINT ' || constraint_name ||
                           ' DO UPDATE ' || set_expression || ' RETURNING *' INTO r USING NEW;
            END CASE;
            ELSE
              RAISE internal_error using message = 'action is not found'; RETURN NULL;
          END IF;
      END CASE;
      IF r IS NULL THEN RETURN null; ELSE RETURN r; END IF;
     ELSE RAISE check_violation using message = 'insert check constraint failed'; RETURN NULL;
     END IF;
  END $$;