/**
 * אחסון קבצים מפורסרים ב-IndexedDB — כך שהשכבות זמינות גם אופליין
 * וגם אחרי סגירת האפליקציה.
 */
(function (global) {
  "use strict";

  var DB_NAME = "optech-gis";
  var DB_VERSION = 1;
  var STORE = "files";

  function open() {
    return new Promise(function (resolve, reject) {
      var req = indexedDB.open(DB_NAME, DB_VERSION);
      req.onupgradeneeded = function () {
        var db = req.result;
        if (!db.objectStoreNames.contains(STORE)) {
          db.createObjectStore(STORE, { keyPath: "id" });
        }
      };
      req.onsuccess = function () { resolve(req.result); };
      req.onerror = function () { reject(req.error); };
    });
  }

  function tx(mode, fn) {
    return open().then(function (db) {
      return new Promise(function (resolve, reject) {
        var t = db.transaction(STORE, mode);
        var store = t.objectStore(STORE);
        var out = fn(store);
        t.oncomplete = function () { db.close(); resolve(out && out.result !== undefined ? out.result : out); };
        t.onerror = function () { db.close(); reject(t.error); };
      });
    });
  }

  function saveFile(record) {
    return tx("readwrite", function (s) { s.put(record); });
  }

  function deleteFile(id) {
    return tx("readwrite", function (s) { s.delete(id); });
  }

  function listFiles() {
    return open().then(function (db) {
      return new Promise(function (resolve, reject) {
        var t = db.transaction(STORE, "readonly");
        var req = t.objectStore(STORE).getAll();
        req.onsuccess = function () { db.close(); resolve(req.result || []); };
        req.onerror = function () { db.close(); reject(req.error); };
      });
    });
  }

  global.Store = {
    saveFile: saveFile,
    deleteFile: deleteFile,
    listFiles: listFiles,
  };
})(window);