pagination

type Config[T any] struct {
	SearchAccessors []SearchAccessor[T]
	// SortBindings order matters: the first binding is the default sort when the
	// requested key is empty or unknown, and serves as the tie-break for every
	// other binding so pagination is deterministic.
	SortBindings    []SortBinding[T]
	FilterAccessors []FilterAccessor[T]
}

type FilterAccessor[T any] struct {
	Key string
	Fn  func(item T, filterValue string) bool
}

type FilterResult[T any] struct {
	Items          []T
	TotalCount     int64
	TotalAvailable int64
}

type Params struct {
	Start int
	Limit int
	// SkipCount opts out of the COUNT(*) query that backs TotalItems/TotalPages.
	// When true, paginated DB helpers return UnknownTotal (-1) for both fields and
	// the response is suitable for infinite-scroll UIs that don't render page numbers.
	// Default (false) preserves the historical behaviour for all existing callers.
	SkipCount bool
}

type QueryParams struct {
	SearchQuery
	SortParams
	Params

	Filters map[string]string
}

type Response struct {
	TotalPages      int64 `json:"totalPages"`
	TotalItems      int64 `json:"totalItems"`
	CurrentPage     int   `json:"currentPage"`
	ItemsPerPage    int   `json:"itemsPerPage"`
	GrandTotalItems int64 `json:"grandTotalItems,omitempty"`
}

type SearchAccessor[T any] = func(T) (string, error)

type SearchQuery struct {
	Search string
}

type SortBinding[T any] struct {
	Key    string
	Fn     SortOption[T]
	DescFn SortOption[T]
}

type SortOption[T any] func(a, b T) int

type SortOrder string

type SortParams struct {
	Sort  string
	Order SortOrder
}