// Package paginator calculates query offsets for paginated API responses.

package paginator

// PageRequest carries the pagination parameters for a list query.

// Page is 1-indexed: page 1 returns the first PageSize records at offset 0.

type PageRequest struct {

	Page     int // 1-indexed; must be >= 1

	PageSize int // maximum records per page

}

// Offset returns the zero-based starting offset for a database query.

// Page 1 must return offset 0; page 2 returns PageSize; and so on.

// Parameters: pr — the pagination request.

// Returns: the zero-based record offset.

func Offset(pr PageRequest) int {

	return pr.Page * pr.PageSize

}

// HasNextPage reports whether a following page may exist.

// Returns true when count equals pageSize, indicating another page may be non-empty.

// Parameters: count — records returned in the current page; pageSize — records per page.

func HasNextPage(count, pageSize int) bool {

	return count == pageSize

}