-- Upgrade the database from commit 53f71f70 to 4d977848.
--
-- NOTE: This upgrade must be applied to every schema in the database.
-- NOTE: Each application starts a transaction, which must be committed
-- or rolled back.
--
-- This adds:
--
--  * label_in_sequence (_sequence integer, _label text):
--    Returns events containing the specified label.
--  
--  * handle_final_line_events (_seq integer, _label text, _column text):
--    - If _label does not exist in the events for sequence _seq:
--      it adds a new _label label at the shotpoint obtained from
--      final_lines_summary[_column].
--    - If _label does exist (and hasn't been auto-added by this function
--      in a previous run), it will add information about it to the final
--      line's metadata.
--  
--  * final_line_post_import (_seq integer):
--    Calls handle_final_line_events() on the given sequence to check
--    for FSP, FGSP, LGSP and LSP labels.
--  
--  * events_seq_labels_single ():
--    Trigger function to ensure that labels that have the attribute
--    `model.multiple` set to `false` occur at most only once per
--    sequence. If a new instance is added to a sequence, the previous
--    instance is deleted.
--  
--  * Trigger on events_seq_labels that calls events_seq_labels_single().
--  
--  * Trigger on events_timed_labels that calls events_seq_labels_single().
--
-- To apply, run as the dougal user, for every schema in the database:
--
-- psql <<EOF
-- SET search_path TO survey_*,public;
-- \i $THIS_FILE
-- COMMIT;
-- EOF
--
-- NOTE: It will fail harmlessly if applied twice.


BEGIN;

CREATE OR REPLACE FUNCTION label_in_sequence (_sequence integer, _label text)
    RETURNS events
    LANGUAGE sql
AS $$
    SELECT * FROM events WHERE sequence = _sequence AND _label = ANY(labels);
$$;

CREATE OR REPLACE PROCEDURE handle_final_line_events (_seq integer, _label text, _column text)
    LANGUAGE plpgsql
AS $$

DECLARE
_line final_lines_summary%ROWTYPE;
_column_value integer;
_tg_name text := 'final_line';
_event events%ROWTYPE;
event_id integer;
BEGIN

    SELECT * INTO _line FROM final_lines_summary WHERE sequence = _seq;
    _event := label_in_sequence(_seq, _label);
    _column_value := row_to_json(_line)->>_column;
    
    --RAISE NOTICE '% is %', _label, _event;
    --RAISE NOTICE 'Line is %', _line;
    --RAISE NOTICE '% is % (%)', _column, _column_value, _label;
    
    IF _event IS NULL THEN
        --RAISE NOTICE 'We will populate the event log from the sequence data';
        
        SELECT id INTO event_id FROM events_seq WHERE sequence = _seq AND point = _column_value ORDER BY id LIMIT 1;
        IF event_id IS NULL THEN
            --RAISE NOTICE '… but there is no existing event so we create a new one for sequence % and point %', _line.sequence, _column_value;
            INSERT INTO events_seq (sequence, point, remarks)
            VALUES (_line.sequence, _column_value, format('%s %s', _label, (SELECT meta->>'lineName' FROM final_lines WHERE sequence = _seq)))
            RETURNING id INTO event_id;
            --RAISE NOTICE 'Created event_id %', event_id;
        END IF;

        --RAISE NOTICE 'Remove any other auto-inserted % labels in sequence %', _label, _seq;
        DELETE FROM events_seq_labels
        WHERE label = _label AND id = (SELECT id FROM events_seq WHERE sequence = _seq AND meta->'auto' ? _label);
        
        --RAISE NOTICE 'We now add a label to the event (id, label) = (%, %)', event_id, _label;
        INSERT INTO events_seq_labels (id, label) VALUES (event_id, _label) ON CONFLICT ON CONSTRAINT events_seq_labels_pkey DO NOTHING;
        
        --RAISE NOTICE 'And also clear the %: % flag from meta.auto for any existing events for sequence %', _label, _tg_name, _seq;
        UPDATE events_seq
        SET meta = meta #- ARRAY['auto', _label]
        WHERE meta->'auto' ? _label AND sequence = _seq AND id <> event_id;
        
        --RAISE NOTICE 'Finally, flag the event as having been had label % auto-created by %', _label, _tg_name;
        UPDATE events_seq
        SET meta = jsonb_set(jsonb_set(meta, '{auto}', COALESCE(meta->'auto', '{}')), ARRAY['auto', _label], to_jsonb(_tg_name))
        WHERE id = event_id;
        
    ELSE
        --RAISE NOTICE 'We may populate the sequence meta from the event log';
        --RAISE NOTICE 'Unless the event log was populated by us previously';
        --RAISE NOTICE 'Populated by us previously? %', _event.meta->'auto'->>_label = _tg_name;
        
        IF _event.meta->'auto'->>_label IS DISTINCT FROM _tg_name THEN
            --RAISE NOTICE 'Adding % found in events log to final_line meta', _label;
            UPDATE final_lines
            SET meta = jsonb_set(meta, ARRAY[_label], to_jsonb(_event.point))
            WHERE sequence = _seq;
        
            --RAISE NOTICE 'Clearing the %: % flag from meta.auto for any existing events in sequence %', _label, _tg_name, _seq;
            UPDATE events_seq
            SET meta = meta #- ARRAY['auto', _label]
            WHERE sequence = _seq AND meta->'auto'->>_label = _tg_name;
            
        END IF;
        
    END IF;
END;
$$;

CREATE OR REPLACE PROCEDURE final_line_post_import (_seq integer)
    LANGUAGE plpgsql
AS $$
BEGIN

CALL handle_final_line_events(_seq, 'FSP', 'fsp');
CALL handle_final_line_events(_seq, 'FGSP', 'fsp');
CALL handle_final_line_events(_seq, 'LGSP', 'lsp');
CALL handle_final_line_events(_seq, 'LSP', 'lsp');

END;
$$;


CREATE OR REPLACE FUNCTION events_seq_labels_single ()
    RETURNS trigger
    LANGUAGE plpgsql
AS $$
DECLARE _sequence integer;
BEGIN
    IF EXISTS(SELECT 1 FROM labels WHERE name = NEW.label AND (data->'model'->'multiple')::boolean IS FALSE) THEN
        SELECT sequence INTO _sequence FROM events WHERE id = NEW.id;
        DELETE
        FROM events_seq_labels
        WHERE
            id <> NEW.id
            AND label = NEW.label
            AND id IN (SELECT id FROM events_seq WHERE sequence = _sequence);
            
        DELETE
        FROM events_timed_labels
        WHERE
            id <> NEW.id
            AND label = NEW.label
            AND id IN (SELECT id FROM events_timed_seq WHERE sequence = _sequence);
    END IF;
    RETURN NULL;
END;
$$;

CREATE TRIGGER events_seq_labels_single_tg AFTER INSERT OR UPDATE ON events_seq_labels FOR EACH ROW EXECUTE FUNCTION events_seq_labels_single();
CREATE TRIGGER events_seq_labels_single_tg AFTER INSERT OR UPDATE ON events_timed_labels FOR EACH ROW EXECUTE FUNCTION events_seq_labels_single();

--
--NOTE Run `COMMIT;` now if all went well
--