-- BUG-1001: rectification titles carry the result, not a date.
-- One formula and one automatic-title predicate. The trigger and the backfill
-- both call them. Do not assign chat_sessions.updated_at (BUG-988 / BUG-704).
-- Open / GET / metadata PATCH still must not retitle (BUG-699): this trigger
-- listens only to accepted_time, confirmed_time, and candidate_range.

begin;

do $migration$
begin
  if current_user <> 'schema_owner' then
    raise exception 'rectification_session_title_result_requires_schema_owner'
      using errcode = '42501';
  end if;
end
$migration$;

create or replace function public.rectification_session_title(
  p_accepted time,
  p_confirmed time,
  p_range jsonb
) returns text
language sql
immutable
parallel safe
set search_path = ''
as $$
  select case
    when p_confirmed is not null then
      '生时校正 · ' || to_char(p_confirmed, 'HH24:MI')
    when p_accepted is not null then
      '生时校正 · ' || to_char(p_accepted, 'HH24:MI')
    when public.agentic_rectification_is_clock(p_range ->> 'start_time')
      and public.agentic_rectification_is_clock(p_range ->> 'end_time') then
      '生时校正 · ' || (p_range ->> 'start_time') || '–' || (p_range ->> 'end_time')
    else
      '生时校正'
  end;
$$;

-- The dash in the range alternative is U+2013 EN DASH, not a hyphen.
-- frontend/src/lib/session-title.ts DATED_ENTRY_TITLE must agree with this
-- predicate. The parity test reads this pattern from this file.
create or replace function public.rectification_session_title_is_automatic(
  p_title text
) returns boolean
language sql
immutable
parallel safe
set search_path = ''
as $$
  select p_title is not null
    and p_title ~ '^(?:(?:生时校正|今日节奏)\s*·\s*[0-9]{1,2}月[0-9]{1,2}日|[0-9]{1,2}月[0-9]{1,2}日\s*·\s*(?:今日节奏|生时校正))(?:\s+[0-9]{2}:[0-9]{2})?$|^生时校正$|^生时校正\s*·\s*[0-9]{2}:[0-9]{2}$|^生时校正\s*·\s*[0-9]{2}:[0-9]{2}–[0-9]{2}:[0-9]{2}$';
$$;

create or replace function public.sync_rectification_session_title_from_case()
returns trigger
language plpgsql
security definer
set search_path = ''
as $$
begin
  update public.chat_sessions
  set title = public.rectification_session_title(new.accepted_time, new.confirmed_time, new.candidate_range)
  where id = new.session_id
    and user_id = new.user_id
    and session_type = 'birth_time_rectification'
    and title is distinct from public.rectification_session_title(new.accepted_time, new.confirmed_time, new.candidate_range)
    and public.rectification_session_title_is_automatic(title);
  return new;
end;
$$;

revoke all on function public.rectification_session_title(time, time, jsonb)
  from public, anon, authenticated;
revoke all on function public.rectification_session_title_is_automatic(text)
  from public, anon, authenticated;
revoke all on function public.sync_rectification_session_title_from_case()
  from public, anon, authenticated;

grant execute on function public.rectification_session_title(time, time, jsonb)
  to schema_owner;
grant execute on function public.rectification_session_title_is_automatic(text)
  to schema_owner, authenticated, service_role;
grant execute on function public.sync_rectification_session_title_from_case()
  to schema_owner;

drop trigger if exists agentic_rectification_cases_title_from_result
  on public.agentic_rectification_cases;

create trigger agentic_rectification_cases_title_from_result
after insert or update of accepted_time, confirmed_time, candidate_range
on public.agentic_rectification_cases
for each row
execute function public.sync_rectification_session_title_from_case();

-- Client PATCH runs as authenticated and would otherwise write the minted
-- title "生时校正" back over the result the insert trigger just stored.
-- This function stays security invoker so current_user is the updating role.
-- The result trigger is security definer, owned by schema_owner, so its
-- update still sees current_user = schema_owner and is allowed.
create or replace function public.keep_rectification_result_title()
returns trigger
language plpgsql
set search_path = ''
as $$
begin
  if current_user <> 'schema_owner'
    and new.session_type = 'birth_time_rectification'
    and public.rectification_session_title_is_automatic(new.title)
    and new.title is distinct from old.title then
    new.title := old.title;
  end if;
  return new;
end;
$$;

revoke all on function public.keep_rectification_result_title()
  from public, anon, authenticated;
grant execute on function public.keep_rectification_result_title()
  to schema_owner;

drop trigger if exists chat_sessions_keep_rectification_result_title
  on public.chat_sessions;

create trigger chat_sessions_keep_rectification_result_title
before update of title on public.chat_sessions
for each row
execute function public.keep_rectification_result_title();

do $backfill$
declare
  retitled integer;
begin
  -- BEGIN rectification_session_title_backfill
  update public.chat_sessions as session
  set title = public.rectification_session_title(case_row.accepted_time, case_row.confirmed_time, case_row.candidate_range)
  from public.agentic_rectification_cases as case_row
  where case_row.session_id = session.id
    and case_row.user_id = session.user_id
    and session.session_type = 'birth_time_rectification'
    and session.title is distinct from public.rectification_session_title(case_row.accepted_time, case_row.confirmed_time, case_row.candidate_range)
    and public.rectification_session_title_is_automatic(session.title);
  -- END rectification_session_title_backfill
  get diagnostics retitled = row_count;
  raise notice 'rectification_session_title_result retitled=%', retitled;
end
$backfill$;

commit;