/**
 * Platform detection shared by web and the Tauri mobile/native builds.
 *
 * - `IS_MOBILE_BUILD` is a *build-time* flag (set by `NEXT_PUBLIC_MOBILE=1`)
 *   used to gate the static export, drop server API routes, and switch auth to
 *   the native flow. It is statically analyzable so dead code is tree-shaken.
 * - `isTauriRuntime()` is a *runtime* check (the same static bundle can be
 *   loaded by a browser during development, e.g. `pnpm dev`, even when built in
 *   mobile mode).
 */

/** True when the bundle was built for the Tauri native shells. */
export const IS_MOBILE_BUILD = process.env.NEXT_PUBLIC_MOBILE === "1"

/**
 * The per-app product this build targets (UltiMail, UltiDrive, …). Drives the
 * default start route, the deep-link scheme, and which sibling apps the suite
 * launcher tries to open. Defaults to `mail` (the pilot).
 */
export type SuiteApp = "mail" | "drive" | "agenda" | "meet" | "chat" | "contacts"

export const SUITE_APP: SuiteApp =
  (process.env.NEXT_PUBLIC_SUITE_APP as SuiteApp | undefined) ?? "mail"

/** Custom URL scheme for this app's deep links, e.g. `ultimail://`. */
export function appScheme(app: SuiteApp = SUITE_APP): string {
  return `ulti${app}`
}

/** Default start route for an app shell. */
export function appStartRoute(app: SuiteApp = SUITE_APP): string {
  switch (app) {
    case "mail":
      return "/mail"
    case "drive":
      return "/drive"
    case "agenda":
      return "/agenda"
    case "meet":
      return "/meet"
    case "chat":
      return "/chat"
    case "contacts":
      return "/contacts"
    default:
      return "/mail"
  }
}

/**
 * Map an in-app route to the suite app that "owns" it, so the launcher can open
 * the sibling native app instead of navigating in-webview. Returns null for
 * routes that should stay in the current app (settings, account, admin, …).
 */
export function suiteAppForRoute(route: string): SuiteApp | null {
  const path = route.split("?")[0]
  if (path.startsWith("/mail")) return "mail"
  if (path.startsWith("/drive")) return "drive"
  if (path.startsWith("/agenda")) return "agenda"
  if (path.startsWith("/meet")) return "agenda" // UltiCal+UltiMeet share one app
  if (path.startsWith("/chat")) return "chat"
  if (path.startsWith("/contacts")) return "contacts"
  return null
}

/** True only when actually executing inside a Tauri webview. */
export function isTauriRuntime(): boolean {
  if (typeof window === "undefined") return false
  return (
    "__TAURI_INTERNALS__" in window ||
    "__TAURI__" in window ||
    // Tauri v2 exposes this in some configurations.
    (window as { isTauri?: boolean }).isTauri === true
  )
}

/**
 * True when we should use the native auth + runtime-config code paths.
 * Mobile builds always use native paths; a mobile build opened in a plain
 * browser (dev) also uses them so the flow can be exercised without a device.
 */
export function useNativeRuntime(): boolean {
  return IS_MOBILE_BUILD || isTauriRuntime()
}