CREATE FUNCTION @extschema@.inherit_template_properties(
    p_parent_table text
    , p_child_schema text
    , p_child_tablename text
)
    RETURNS boolean
    LANGUAGE plpgsql
    AS $$
DECLARE

v_child_relkind         char;
v_child_schema          text;
v_child_tablename       text;
v_child_unlogged        char;
v_dupe_found            boolean := false;
v_index_list            record;
v_parent_index_list     record;
v_parent_oid            oid;
v_parent_table          text;
v_relopt                record;
v_sql                   text;
v_template_oid          oid;
v_template_schemaname   text;
v_template_table        text;
v_template_tablename    name;
v_template_unlogged     char;

BEGIN
/*
 * Function to inherit the properties of the template table to newly created child tables.
 * For PG14+, used to inherit non-partition-key unique indexes & primary keys, unlogged status, and relation options
 */

SELECT parent_table, template_table
INTO v_parent_table, v_template_table
FROM @extschema@.part_config
WHERE parent_table = p_parent_table;
IF v_parent_table IS NULL THEN
    RAISE EXCEPTION 'Given parent table has no configuration in pg_partman: %', p_parent_table;
ELSIF v_template_table IS NULL THEN
    RAISE EXCEPTION 'No template table set in configuration for given parent table: %', p_parent_table;
END IF;

SELECT c.oid INTO v_parent_oid
FROM pg_catalog.pg_class c
JOIN pg_catalog.pg_namespace n ON c.relnamespace = n.oid
WHERE n.nspname = split_part(p_parent_table, '.', 1)::name
AND c.relname = split_part(p_parent_table, '.', 2)::name;
    IF v_parent_oid IS NULL THEN
        RAISE EXCEPTION 'Unable to find given parent table in system catalogs: %', p_parent_table;
    END IF;

SELECT n.nspname, c.relname, c.relkind INTO v_child_schema, v_child_tablename, v_child_relkind
FROM pg_catalog.pg_class c
JOIN pg_catalog.pg_namespace n ON c.relnamespace = n.oid
WHERE n.nspname = p_child_schema::name
AND c.relname = p_child_tablename::name;
    IF v_child_tablename IS NULL THEN
        RAISE EXCEPTION 'Unable to find given child table in system catalogs: %.%', v_child_schema, v_child_tablename;
    END IF;

IF v_child_relkind = 'p' THEN
    -- Subpartitioned parent, do not apply properties
    RAISE DEBUG 'inherit_template_properties: found given child is subpartition parent, so properties not inherited';
    RETURN false;
END IF;

v_template_schemaname := split_part(v_template_table, '.', 1)::name;
v_template_tablename :=  split_part(v_template_table, '.', 2)::name;

SELECT c.oid INTO v_template_oid
FROM pg_catalog.pg_class c
JOIN pg_catalog.pg_namespace n ON c.relnamespace = n.oid
LEFT OUTER JOIN pg_catalog.pg_tablespace ts ON c.reltablespace = ts.oid
WHERE n.nspname = v_template_schemaname
AND c.relname = v_template_tablename;
    IF v_template_oid IS NULL THEN
        RAISE EXCEPTION 'Unable to find configured template table in system catalogs: %', v_template_table;
    END IF;

-- Index creation (Only for unique, non-partition key indexes)
FOR v_index_list IN
    SELECT
    array_to_string(regexp_matches(pg_get_indexdef(indexrelid), ' USING .*'),',') AS statement
    , i.indisprimary
    , i.indisunique
    , ( SELECT array_agg( a.attname ORDER by x.r )
        FROM pg_catalog.pg_attribute a
        JOIN ( SELECT k, row_number() over () as r
                FROM unnest(i.indkey) k ) as x
        ON a.attnum = x.k AND a.attrelid = i.indrelid
    ) AS indkey_names
    , c.relname AS index_name
    , ts.spcname AS tablespace_name
    FROM pg_catalog.pg_index i
    JOIN pg_catalog.pg_class c ON i.indexrelid = c.oid
    LEFT OUTER JOIN pg_catalog.pg_tablespace ts ON c.reltablespace = ts.oid
    WHERE i.indrelid = v_template_oid
    AND i.indisvalid
    AND (i.indisprimary OR i.indisunique)
    ORDER BY 1
LOOP
    v_dupe_found := false;

    FOR v_parent_index_list IN
        SELECT
        array_to_string(regexp_matches(pg_get_indexdef(indexrelid), ' USING .*'),',') AS statement
        , i.indisprimary
        , ( SELECT array_agg( a.attname ORDER by x.r )
            FROM pg_catalog.pg_attribute a
            JOIN ( SELECT k, row_number() over () as r
                    FROM unnest(i.indkey) k ) as x
            ON a.attnum = x.k AND a.attrelid = i.indrelid
        ) AS indkey_names
        FROM pg_catalog.pg_index i
        WHERE i.indrelid = v_parent_oid
        AND i.indisvalid
        ORDER BY 1
    LOOP

        IF v_parent_index_list.indisprimary AND v_index_list.indisprimary THEN
            IF v_parent_index_list.indkey_names = v_index_list.indkey_names THEN
                RAISE DEBUG 'inherit_template_properties: Ignoring duplicate primary key on template table: % ', v_index_list.indkey_names;
                v_dupe_found := true;
                CONTINUE; -- only continue within this nested loop
            END IF;
        END IF;

        IF v_parent_index_list.statement = v_index_list.statement THEN
            RAISE DEBUG 'inherit_template_properties: Ignoring duplicate unique index on template table: %', v_index_list.statement;
            v_dupe_found := true;
            CONTINUE; -- only continue within this nested loop
        END IF;

    END LOOP; -- end parent index loop

    IF v_dupe_found = true THEN
        CONTINUE;
    END IF;

    IF v_index_list.indisprimary THEN
        v_sql := format('ALTER TABLE %I.%I ADD PRIMARY KEY (%s)'
                        , v_child_schema
                        , v_child_tablename
                        , '"' || array_to_string(v_index_list.indkey_names, '","') || '"');
        IF v_index_list.tablespace_name IS NOT NULL THEN
            v_sql := v_sql || format(' USING INDEX TABLESPACE %I', v_index_list.tablespace_name);
        END IF;
        RAISE DEBUG 'inherit_template_properties: Create pk: %', v_sql;
        EXECUTE v_sql;
    ELSIF v_index_list.indisunique THEN
        -- statement column should be just the portion of the index definition that defines what it actually is
        v_sql := format('CREATE UNIQUE INDEX ON %I.%I %s', v_child_schema, v_child_tablename, v_index_list.statement);
        IF v_index_list.tablespace_name IS NOT NULL THEN
            IF (ARRAY_length(regexp_matches(v_sql, ' WHERE ', 'i'), 1) > 0) THEN
                v_sql := regexp_replace(v_sql, ' WHERE ', format(' TABLESPACE %I WHERE ', v_index_list.tablespace_name), 'i');
            ELSE
                v_sql := v_sql || format(' TABLESPACE %I', v_index_list.tablespace_name);
            END IF;
        END IF;

        RAISE DEBUG 'inherit_template_properties: Create index: %', v_sql;
        EXECUTE v_sql;
    ELSE
        RAISE EXCEPTION 'inherit_template_properties: Unexpected code path in unique index creation. Please report the steps that lead to this error to extension maintainers.';
    END IF;

END LOOP;
-- End index creation

/*
UNLOGGED status.
    As of PG12, the unlogged/logged status of a parent table cannot be changed via an ALTER TABLE in order to affect its children.
    As of partman v4.2x, the unlogged state will be managed via the template table. See 4.2.0 release notes.
    As of PG18, the unlogged flag cannot be set on the parent table. But it can be set on the child tables. So it can continue to be supported
      in pg_partman via the template table for now.
*/

SELECT relpersistence INTO v_template_unlogged
FROM pg_catalog.pg_class c
JOIN pg_catalog.pg_namespace n ON c.relnamespace = n.oid
WHERE n.nspname = v_template_schemaname
AND c.relname = v_template_tablename;

SELECT relpersistence INTO v_child_unlogged
FROM pg_catalog.pg_class c
JOIN pg_catalog.pg_namespace n ON c.relnamespace = n.oid
WHERE n.nspname = v_child_schema::name
AND c.relname = v_child_tablename::name;

IF v_template_unlogged = 'u' AND v_child_unlogged = 'p'  THEN
    v_sql := format ('ALTER TABLE %I.%I SET UNLOGGED', v_child_schema, v_child_tablename);
    RAISE DEBUG 'inherit_template_properties: Alter UNLOGGED: %', v_sql;
    EXECUTE v_sql;
ELSIF v_template_unlogged = 'p' AND v_child_unlogged = 'u'  THEN
    v_sql := format ('ALTER TABLE %I.%I SET LOGGED', v_child_schema, v_child_tablename);
    RAISE DEBUG 'inherit_template_properties: Alter UNLOGGED: %', v_sql;
    EXECUTE v_sql;
END IF;

-- Relation options are not either not being inherited or not supported (autovac tuning) on <= PG15
FOR v_relopt IN
    SELECT unnest(reloptions) as value
    FROM pg_catalog.pg_class
    WHERE oid = v_template_oid
LOOP
    v_sql := format('ALTER TABLE %I.%I SET (%s)'
                    , v_child_schema
                    , v_child_tablename
                    , v_relopt.value);
    RAISE DEBUG 'inherit_template_properties: Set relopts: %', v_sql;
    EXECUTE v_sql;
END LOOP;
RETURN true;

END
$$;
