import { DEFAULT_SETTINGS, OPEN_IN_VALUES } from "./defaults.js";

export function normalizeLanguage(value) {
  if (typeof value !== "string") return "";
  const trimmed = value.trim();
  return [...trimmed].length <= 100 && !/[\r\n\x00-\x1f]/u.test(trimmed) ? trimmed : "";
}

// Pure. Layers stored values over the defaults, dropping unknown keys and
// falling back on wrong types or out-of-range values. A fresh or signed-out
// profile returns {} from storage, which yields the defaults.
export function mergeSettings(stored) {
  const merged = { ...DEFAULT_SETTINGS };
  if (stored === null || typeof stored !== "object") {
    return merged;
  }
  merged.contextMenuMode = ["off", "simple", "advanced"].includes(stored.contextMenuMode)
    ? stored.contextMenuMode : stored.showContextMenu === false ? "off" : "simple";
  if (typeof stored.showTranslate === "boolean") merged.showTranslate = stored.showTranslate;
  if (["ask", "preferred"].includes(stored.translationMode)) merged.translationMode = stored.translationMode;
  merged.translationLanguage = normalizeLanguage(stored.translationLanguage);
  if (typeof stored.temporaryChat === "boolean") {
    merged.temporaryChat = stored.temporaryChat;
  }
  if (typeof stored.webSearch === "boolean") {
    merged.webSearch = stored.webSearch;
  }
  if (OPEN_IN_VALUES.includes(stored.openIn)) {
    merged.openIn = stored.openIn;
  }
  if (typeof stored.promptTemplate === "string") {
    merged.promptTemplate = stored.promptTemplate;
  }
  return merged;
}

// storage.sync works with no Mozilla account (it behaves as local storage and
// syncs later if the user signs in), so no capability probe is needed. Any
// rejection falls back to defaults rather than blocking the user's action.
// Firefox sanitises all non-quota backend errors to a single generic string, so
// there is nothing useful to branch on.
export async function load() {
  try {
    const stored = await browser.storage.sync.get([...Object.keys(DEFAULT_SETTINGS), "showContextMenu"]);
    return mergeSettings(stored);
  } catch {
    return mergeSettings(null);
  }
}

export async function save(partial) {
  const normalized = mergeSettings(partial);
  const patch = {};
  if (partial && typeof partial === "object") {
    for (const key of Object.keys(DEFAULT_SETTINGS)) {
      if (Object.hasOwn(partial, key)) patch[key] = normalized[key];
    }
    if (Object.hasOwn(partial, "showContextMenu")) patch.contextMenuMode = normalized.contextMenuMode;
  }
  await browser.storage.sync.set(patch);
}