martials.no/src/utils/linking.ts

import type { AvailableLanguageTag } from "@/paraglide/runtime.js"
import type { AbsolutePathname, Project } from "@/types/types.ts"

interface TranslatedPathnames {
  nb: AbsolutePathname
  en: `/en${AbsolutePathname}`
}

export type NavLink =
  | "/"
  | "/contact"
  | "/projects"
  | `/projects/${Project["id"]}`
  | "/links"
  | "/uses"

const paths: Set<NavLink> = new Set([
  "/",
  "/contact",
  "/projects",
  "/links",
  "/uses",
])

const projectPaths: Set<string> = new Set<string>(["homepage", "sb1budget"])

/**
 * Defines the localized pathnames for the site.
 * The key must be used to navigate to the correct path.
 * The value is the path that will be used for the given locale.
 *
 * @see https://inlang.com/m/iljlwzfs/paraglide-astro-i18n
 */
const pathnames: Record<AbsolutePathname, TranslatedPathnames> = {}
for (const path of paths) {
  pathnames[path] = {
    nb: path,
    en: `/en${path}`,
  }
}

export function localizePathname(
  pathname: NavLink,
  locale: AvailableLanguageTag,
): string {
  const pathnameParts = pathname.split("/")
  const firstSegment: AbsolutePathname = `/${pathnameParts[1]}`

  if (pathnames[firstSegment]) {
    const localizedPathname = pathnames[firstSegment][locale]

    const rest = pathnameParts.slice(2)
    if (rest.length > 0) {
      return `${localizedPathname}/${rest.join("/")}`
    } else {
      return localizedPathname
    }
  }
  return pathname
}

export function resolvePathname(pathname: string): AbsolutePathname {
  if (pathname.startsWith("/en")) {
    return pathname.slice(3) as AbsolutePathname
  }
  return pathname as AbsolutePathname
}

export function isAbsolutePathname(path: string): path is AbsolutePathname {
  return path.startsWith("/")
}

export function isNavLink(path: string): path is NavLink {
  if (path.startsWith("/en")) {
    path = path.slice(2)
  }
  if (paths.has(path as NavLink)) {
    return true
  }
  const pathSplit = path.split("/").slice(1)
  return (
    pathSplit.length === 2 &&
    pathSplit[0] === "projects" &&
    projectPaths.has(pathSplit[1])
  )
}