// fixtures/status.mjs — the editor's save line and its load-error line,
// factored out of editor-entry.js so the rules are testable under plain
// Node (status.test.mjs).
//
// The save line is estilo's savestatus (the template renders it with
// every state's words from the catalog; its module, served at
// static/estilo/save-status.<hash>.mjs, moves it between them). Its
// four states: `saved`, `saving`, `retrying` (a save is being retried —
// the network, or a 5xx) and `failed` (a batch was DROPPED: the server
// refused it with a 4xx, and the person's Y.Doc now holds changes the
// server never will). The last two are different words on purpose:
// "Offline, retrying" on a batch nobody is retrying tells a person to
// wait for something that will not happen.
//
// A slide that would not load is not a save state — savestatus has no
// word for it — so it is its own line ([slides-load-error]), said until
// a slide does load, and independent of whatever the save line says.

/** The save queue's status word (save-queue.mjs) as a savestatus state. */
export function queueStatusState (state) {
  if (state === 'ok') return 'saved'
  if (state === 'failed') return 'failed'
  return 'retrying'
}

/**
 * The state to show. A dropped batch outranks everything — it is the
 * one fact the person has to act on — and stays for the session; then
 * whatever the queue says.
 */
export function statusState ({ queueState = 'saved', sessionFailed = false } = {}) {
  if (sessionFailed) return 'failed'
  return queueState
}

/**
 * The editor's status: setSave is savestatus's setter, errorEl the
 * load-error line, errorText its words. Returns {save, drop,
 * loadFailed}: save(state) records the queue's state (or re-shows the
 * current one with no argument), drop() marks the session failed,
 * loadFailed(bool) says or clears the load error.
 */
export function createEditorStatus ({ setSave, errorEl, errorText }) {
  let queueState = 'saved'
  let sessionFailed = false
  function save (state) {
    if (state) queueState = state
    setSave(statusState({ queueState, sessionFailed }))
  }
  return {
    save,
    drop () { sessionFailed = true; save() },
    loadFailed (failed) { if (errorEl) errorEl.textContent = failed ? (errorText || '') : '' }
  }
}

/**
 * Loads estilo's savestatus module (its fingerprinted URL is on the
 * root as data-save-status-module) and mounts it on the line. A module
 * that will not load leaves the load-error line saying so and rejects:
 * an editor whose save line cannot move is one that would say "Saved"
 * over changes it never saved.
 */
export async function mountSaveStatus (root, load = src => import(src)) {
  const errorEl = root.querySelector('[slides-load-error]')
  const errorText = root.dataset.textError
  try {
    const { mount } = await load(root.dataset.saveStatusModule)
    return createEditorStatus({ setSave: mount(root.querySelector('[estilo-save-status]')), errorEl, errorText })
  } catch (err) {
    if (errorEl) errorEl.textContent = errorText || ''
    throw err
  }
}