package syncapi

import (
	"context"
	"slices"
)

// pushRulesType is the account data push rules travel as. The push server
// renders it rather than the account data store, because a user who never
// changed a rule has none stored and still has the server defaults.
const pushRulesType = "m.push_rules"

// UnreadNotifications is a joined room's unread counts for the user
// syncing.
type UnreadNotifications struct {
	NotificationCount int `json:"notification_count"`
	HighlightCount    int `json:"highlight_count"`
}

// unreadNotifications fills in the counts of every joined room in the
// response, in one read.
//
// Every joined room reported gets its counts, not only the ones whose
// counts moved: a room is in a response because something in it changed,
// and a client showing a new message wants the count beside it whether or
// not this particular sync is the one that moved it.
func (s *API) unreadNotifications(ctx context.Context, userID string, resp *Response) error {
	if s.push == nil || len(resp.Rooms.Join) == 0 {
		return nil
	}
	roomIDs := make([]string, 0, len(resp.Rooms.Join))
	for roomID := range resp.Rooms.Join {
		roomIDs = append(roomIDs, roomID)
	}
	slices.Sort(roomIDs)

	counts, err := s.push.NotificationCounts(ctx, userID, roomIDs)
	if err != nil {
		return err
	}
	for _, roomID := range roomIDs {
		room := resp.Rooms.Join[roomID]
		c := counts[roomID]
		room.UnreadNotifications = &UnreadNotifications{
			NotificationCount: c.Notifications,
			HighlightCount:    c.Highlights,
		}
		resp.Rooms.Join[roomID] = room
	}
	return nil
}