package fa

import (
	"fmt"
	"strconv"
)

// SubmissionID identifies a submission. FA exposes these as positive integers
// in URLs of the form /view/{id}/.
type SubmissionID int64

func (id SubmissionID) String() string { return strconv.FormatInt(int64(id), 10) }

// JournalID identifies a journal entry. URL form: /journal/{id}/.
type JournalID int64

func (id JournalID) String() string { return strconv.FormatInt(int64(id), 10) }

// CommentID identifies a comment within a submission or journal page.
type CommentID int64

func (id CommentID) String() string { return strconv.FormatInt(int64(id), 10) }

// parseID parses a positive integer from a string and returns it as T.
// Returns 0 and a wrapped error if s is empty or non-numeric. Used by parsers
// to extract IDs from hrefs.
func parseID[T ~int64](s string) (T, error) {
	if s == "" {
		return 0, fmt.Errorf("parse id: empty string")
	}
	n, err := strconv.ParseInt(s, 10, 64)
	if err != nil {
		return 0, fmt.Errorf("parse id %q: %w", s, err)
	}
	return T(n), nil
}