package router

import "regexp"

// IsAgendaQuestion answers whether an utterance asks about the owner's own
// schedule, as opposed to merely naming a day.
//
// It exists because the calendar query source used to match on a day word and
// nothing else (Vikunja #552). Every world question that happened to name a
// day was claimed by the calendar and answered with an empty schedule: "какой
// сегодня курс доллара" replied "на 05.08.2026 ничего нет", which reads as an
// answer about a subject she never looked at. V-474 had already fixed one
// instance of the class by teaching the calendar to step aside on weather
// wording. Sunset, holidays, exchange rates and world news are the same class
// and weather wording does not cover them.
//
// Three arms, and the order is only readability — any one of them is enough:
//
//   - an agenda grammar already claims the phrasing. Reusing
//     AgendaQueryGrammars means the rule that ROUTES a question to the query
//     chain and the rule that lets the CALENDAR answer it cannot drift apart.
//   - the utterance names a scheduled thing. Wider than the grammars on
//     purpose: "какие встречи завтра" carries no possessive and no plan noun,
//     so no grammar claims it, and it is plainly a calendar question.
//   - the question names no subject of its own. "что сегодня?" is his agenda
//     by default, because there is nothing else for it to be about. This is
//     the same test the bare-imperative Praxis arm applies.
//
// Not a routing decision and not a fact, so a pattern is the right mechanism
// here: it selects which source answers, and every source below still runs
// when it returns false.
func IsAgendaQuestion(u string) bool {
	for _, g := range AgendaQueryGrammars() {
		if g.Pattern.MatchString(u) {
			return true
		}
	}
	return scheduledThing.MatchString(u) || subjectlessDayQuestion.MatchString(u)
}

// scheduledThing — the nouns that name something on a calendar. Closed in the
// sense that matters: these are the words for an appointment itself, not the
// words for what an appointment is about. The stems are the union of the ones
// AgendaQueryGrammars already carries, read here as a noun test rather than as
// part of a phrasing.
//
// Stems and not whole words, because Russian declines them and "какие встречи"
// and "на встречу" are one question.
var scheduledThing = regexp.MustCompile(`(?i)(календар|расписани|повестк|планёрк|планерк|встреч|созвон|митинг|совещани|приём|прием|собеседовани|тренировк|занятие|занятия)`)

// subjectlessDayQuestion — "что сегодня?", "что там на завтра", "что в среду".
// An interrogative, an optional preposition, a day word, and nothing else. The
// anchors at both ends are the whole point: the moment the sentence names what
// it is asking about, it stops being his agenda and this must not match.
var subjectlessDayQuestion = regexp.MustCompile(
	`(?i)^\s*(что|чего|какие|сколько|what)\s+(там\s+|ещё\s+|еще\s+)?(на\s+|в\s+|во\s+)?` +
		dayWordPattern + `\s*[?!.]*$`)