package db

import (
	"database/sql"
	"errors"
)

// false on a fresh db, so the client replays from 0 instead of the live tail
func GetCursor(e Execer) (timeUs int64, ok bool, err error) {
	err = e.QueryRow(`select last_time_us from jetstream_cursor where id = 0`).Scan(&timeUs)
	if errors.Is(err, sql.ErrNoRows) {
		return 0, false, nil
	}
	return timeUs, err == nil, err
}

// max keeps a rewound replay from dragging the cursor back
func SaveCursor(e Execer, timeUs int64) error {
	_, err := e.Exec(
		`insert into jetstream_cursor (id, last_time_us) values (0, ?)
		 on conflict(id) do update set last_time_us = max(last_time_us, excluded.last_time_us)`,
		timeUs,
	)
	return err
}

func GetBootstrapUs(e Execer) int64 {
	var us int64
	_ = e.QueryRow(`select time_us from ingest_bootstrap where id = 0`).Scan(&us)
	return us
}