package router

import (
	"fmt"
	"strings"
	"time"
)

// CalendarEventFormatter formats calendar events into a Russian reply string.
type CalendarEventFormatter struct{}

// CalendarEntry — one event to recite. Uncertain marks an event maven did not
// read off a calendar server: the work calendar arrives as relayed phone
// notifications (Vikunja #126), stored below full confidence, and she says so
// rather than reciting a guess as fact.
type CalendarEntry struct {
	Text      string
	Uncertain bool
}

// Format returns a Russian reply for the given calendar events on the given
// date. Every event is treated as certain — use FormatEntries when provenance
// differs between them.
func (f CalendarEventFormatter) Format(events []string, date time.Time) string {
	entries := make([]CalendarEntry, len(events))
	for i, e := range events {
		entries[i] = CalendarEntry{Text: e}
	}
	return f.FormatEntries(entries, date)
}

// FormatEntries returns a Russian reply, hedging the entries maven is not sure
// about. "похоже" and not "возможно": the notification did arrive, what is
// uncertain is whether it describes the meeting correctly.
func (CalendarEventFormatter) FormatEntries(entries []CalendarEntry, date time.Time) string {
	dateStr := date.Format("02.01.2006")
	if len(entries) == 0 {
		return fmt.Sprintf("на %s ничего нет.", dateStr)
	}
	parts := make([]string, len(entries))
	for i, e := range entries {
		if e.Uncertain {
			parts[i] = "похоже, " + e.Text
			continue
		}
		parts[i] = e.Text
	}
	return fmt.Sprintf("на %s: %s", dateStr, strings.Join(parts, "; "))
}