/*
 * Create the trigger function for the parent table of a time-based partition set
 */
CREATE FUNCTION create_time_function(p_parent_table text) RETURNS void
    LANGUAGE plpgsql SECURITY DEFINER
    AS $$
DECLARE

v_control                       text;
v_current_partition_name        text;
v_current_partition_timestamp   timestamptz;
v_datetime_string               text;
v_final_partition_timestamp     timestamptz;
v_job_id                        bigint;
v_jobmon_schema                 text;
v_old_search_path               text;
v_next_partition_name           text;
v_next_partition_timestamp      timestamptz;
v_part_interval                 interval;
v_premake                       int;
v_prev_partition_name           text;
v_prev_partition_timestamp      timestamptz;
v_step_id                       bigint;
v_trig_func                     text;
v_type                          text;

BEGIN

SELECT nspname INTO v_jobmon_schema FROM pg_namespace n, pg_extension e WHERE e.extname = 'pg_jobmon' AND e.extnamespace = n.oid;
IF v_jobmon_schema IS NOT NULL THEN
    SELECT current_setting('search_path') INTO v_old_search_path;
    EXECUTE 'SELECT set_config(''search_path'',''@extschema@,'||v_jobmon_schema||''',''false'')';
END IF;

IF v_jobmon_schema IS NOT NULL THEN
    v_job_id := add_job('PARTMAN CREATE FUNCTION: '||p_parent_table);
    v_step_id := add_step(v_job_id, 'Creating partition function for table '||p_parent_table);
END IF;

SELECT type
    , part_interval::interval
    , control
    , premake
    , datetime_string
INTO v_type
    , v_part_interval
    , v_control
    , v_premake
    , v_datetime_string
FROM @extschema@.part_config 
WHERE parent_table = p_parent_table
AND (type = 'time-static' OR type = 'time-dynamic');

IF NOT FOUND THEN
    RAISE EXCEPTION 'ERROR: no config found for %', p_parent_table;
END IF;

IF v_type = 'time-static' THEN

    CASE
        WHEN v_part_interval = '15 mins' THEN
            v_current_partition_timestamp := date_trunc('hour', CURRENT_TIMESTAMP) + 
                '15min'::interval * floor(date_part('minute', CURRENT_TIMESTAMP) / 15.0);
        WHEN v_part_interval = '30 mins' THEN
            v_current_partition_timestamp := date_trunc('hour', CURRENT_TIMESTAMP) + 
                '30min'::interval * floor(date_part('minute', CURRENT_TIMESTAMP) / 30.0);
        WHEN v_part_interval = '1 hour' THEN
            v_current_partition_timestamp := date_trunc('hour', CURRENT_TIMESTAMP);
         WHEN v_part_interval = '1 day' THEN
            v_current_partition_timestamp := date_trunc('day', CURRENT_TIMESTAMP);
        WHEN v_part_interval = '1 week' THEN
            v_current_partition_timestamp := date_trunc('week', CURRENT_TIMESTAMP);
        WHEN v_part_interval = '1 month' THEN
            v_current_partition_timestamp := date_trunc('month', CURRENT_TIMESTAMP);
        WHEN v_part_interval = '3 months' THEN
            v_current_partition_timestamp := date_trunc('quarter', CURRENT_TIMESTAMP);
        WHEN v_part_interval = '1 year' THEN
            v_current_partition_timestamp := date_trunc('year', CURRENT_TIMESTAMP);
    END CASE;
    
    v_current_partition_name := p_parent_table || '_p' || to_char(v_current_partition_timestamp, v_datetime_string);
    v_next_partition_timestamp := v_current_partition_timestamp + v_part_interval::interval;

    v_trig_func := 'CREATE OR REPLACE FUNCTION '||p_parent_table||'_part_trig_func() RETURNS trigger LANGUAGE plpgsql AS $t$ 
        BEGIN 
        IF TG_OP = ''INSERT'' THEN 
            IF NEW.'||v_control||' >= '||quote_literal(v_current_partition_timestamp)||' AND NEW.'||v_control||' < '||quote_literal(v_next_partition_timestamp)|| ' THEN 
                INSERT INTO '||v_current_partition_name||' VALUES (NEW.*); ';
    FOR i IN 1..v_premake LOOP
        v_prev_partition_timestamp := v_current_partition_timestamp - (v_part_interval::interval * i);
        v_next_partition_timestamp := v_current_partition_timestamp + (v_part_interval::interval * i);
        v_final_partition_timestamp := v_next_partition_timestamp + (v_part_interval::interval);
        v_prev_partition_name := p_parent_table || '_p' || to_char(v_prev_partition_timestamp, v_datetime_string);
        v_next_partition_name := p_parent_table || '_p' || to_char(v_next_partition_timestamp, v_datetime_string);

        v_trig_func := v_trig_func ||'
            ELSIF NEW.'||v_control||' >= '||quote_literal(v_prev_partition_timestamp)||' AND NEW.'||v_control||' < '||
                    quote_literal(v_prev_partition_timestamp + v_part_interval::interval)|| ' THEN 
                INSERT INTO '||v_prev_partition_name||' VALUES (NEW.*); 
            ELSIF NEW.'||v_control||' >= '||quote_literal(v_next_partition_timestamp)||' AND NEW.'||v_control||' < '||
                    quote_literal(v_final_partition_timestamp)|| ' THEN 
                INSERT INTO '||v_next_partition_name||' VALUES (NEW.*); ';
    END LOOP;
    v_trig_func := v_trig_func ||' 
            ELSE 
                RETURN NEW; 
            END IF; 
        END IF; 
        RETURN NULL; 
        END $t$;';

    EXECUTE v_trig_func;

    IF v_jobmon_schema IS NOT NULL THEN
        PERFORM update_step(v_step_id, 'OK', 'Added function for current time interval: '||
            v_current_partition_timestamp||' to '||(v_final_partition_timestamp-'1sec'::interval));
    END IF;

ELSIF v_type = 'time-dynamic' THEN

    v_trig_func := 'CREATE OR REPLACE FUNCTION '||p_parent_table||'_part_trig_func() RETURNS trigger LANGUAGE plpgsql AS $t$ 
        DECLARE
            v_count                 int;
            v_partition_name        text;
            v_partition_timestamp   timestamptz;
            v_schemaname            text;
            v_tablename             text;
        BEGIN 
        IF TG_OP = ''INSERT'' THEN 
            ';
        CASE
            WHEN v_part_interval = '15 mins' THEN 
                v_trig_func := v_trig_func||'v_partition_timestamp := date_trunc(''hour'', NEW.'||v_control||') + 
                    ''15min''::interval * floor(date_part(''minute'', NEW.'||v_control||') / 15.0);';
            WHEN v_part_interval = '30 mins' THEN
                v_trig_func := v_trig_func||'v_partition_timestamp := date_trunc(''hour'', NEW.'||v_control||') + 
                    ''30min''::interval * floor(date_part(''minute'', NEW.'||v_control||') / 30.0);';
            WHEN v_part_interval = '1 hour' THEN
                v_trig_func := v_trig_func||'v_partition_timestamp := date_trunc(''hour'', NEW.'||v_control||');';
             WHEN v_part_interval = '1 day' THEN
                v_trig_func := v_trig_func||'v_partition_timestamp := date_trunc(''day'', NEW.'||v_control||');';
            WHEN v_part_interval = '1 week' THEN
                v_trig_func := v_trig_func||'v_partition_timestamp := date_trunc(''week'', NEW.'||v_control||');';
            WHEN v_part_interval = '1 month' THEN
                v_trig_func := v_trig_func||'v_partition_timestamp := date_trunc(''month'', NEW.'||v_control||');';
            WHEN v_part_interval = '3 months' THEN
                v_trig_func := v_trig_func||'v_partition_timestamp := date_trunc(''quarter'', NEW.'||v_control||');';
            WHEN v_part_interval = '1 year' THEN
                v_trig_func := v_trig_func||'v_partition_timestamp := date_trunc(''year'', NEW.'||v_control||');';
        END CASE;

        v_trig_func := v_trig_func||'
            v_partition_name := '''||p_parent_table||'_p''|| to_char(v_partition_timestamp, '||quote_literal(v_datetime_string)||');
            v_schemaname := split_part(v_partition_name, ''.'', 1); 
            v_tablename := split_part(v_partition_name, ''.'', 2);
            SELECT count(*) INTO v_count FROM pg_tables WHERE schemaname = v_schemaname AND tablename = v_tablename;
            IF v_count > 0 THEN 
                EXECUTE ''INSERT INTO ''||v_partition_name||'' VALUES($1.*)'' USING NEW;
            ELSE
                RETURN NEW;
            END IF;
        END IF;
        
        RETURN NULL; 
        END $t$;';

    EXECUTE v_trig_func;

    IF v_jobmon_schema IS NOT NULL THEN
        PERFORM update_step(v_step_id, 'OK', 'Added function for dynamic time table: '||p_parent_table);
    END IF;

ELSE
    RAISE EXCEPTION 'ERROR: Invalid time partitioning type given: %', v_type;
END IF;

IF v_jobmon_schema IS NOT NULL THEN
    PERFORM close_job(v_job_id);
    EXECUTE 'SELECT set_config(''search_path'','''||v_old_search_path||''',''false'')';
END IF;

EXCEPTION
    WHEN OTHERS THEN
        IF v_jobmon_schema IS NOT NULL THEN
            EXECUTE 'SELECT set_config(''search_path'',''@extschema@,'||v_jobmon_schema||''',''false'')';
            IF v_job_id IS NULL THEN
                v_job_id := add_job('PARTMAN CREATE FUNCTION: '||p_parent_table);
                v_step_id := add_step(v_job_id, 'Partition function maintenance for table '||p_parent_table||' failed');
            ELSIF v_step_id IS NULL THEN
                v_step_id := add_step(v_job_id, 'EXCEPTION before first step logged');
            END IF;
            PERFORM update_step(v_step_id, 'CRITICAL', 'ERROR: '||coalesce(SQLERRM,'unknown'));
            PERFORM fail_job(v_job_id);
            EXECUTE 'SELECT set_config(''search_path'','''||v_old_search_path||''',''false'')';
        END IF;
        RAISE EXCEPTION '%', SQLERRM;
END
$$;