import type { RecoveryStorage } from "@platform/projectStorage";

export const browserRecoveryStorage: RecoveryStorage = {
  async read(key) {
    return request<string | undefined>("readonly", (store) => store.get(key)).then((value) => value ?? null);
  },
  async write(key, value) {
    await request("readwrite", (store) => store.put(value, key));
  },
  async remove(key) {
    await request("readwrite", (store) => store.delete(key));
  },
};

const RECOVERY_DATABASE = "image-studio";
const RECOVERY_STORE = "recovery";

function openRecoveryDatabase(): Promise<IDBDatabase> {
  return new Promise((resolve, reject) => {
    const open = indexedDB.open(RECOVERY_DATABASE, 1);
    open.onupgradeneeded = () => {
      if (!open.result.objectStoreNames.contains(RECOVERY_STORE)) open.result.createObjectStore(RECOVERY_STORE);
    };
    open.onsuccess = () => resolve(open.result);
    open.onerror = () => reject(open.error ?? new Error("Could not open recovery storage."));
  });
}

async function request<T>(mode: IDBTransactionMode, operation: (store: IDBObjectStore) => IDBRequest<T>): Promise<T> {
  const database = await openRecoveryDatabase();
  return new Promise((resolve, reject) => {
    const transaction = database.transaction(RECOVERY_STORE, mode);
    const databaseRequest = operation(transaction.objectStore(RECOVERY_STORE));
    databaseRequest.onsuccess = () => resolve(databaseRequest.result);
    databaseRequest.onerror = () => reject(databaseRequest.error ?? new Error("Recovery storage operation failed."));
    transaction.oncomplete = () => database.close();
    transaction.onerror = () => {
      database.close();
      reject(transaction.error ?? new Error("Recovery storage transaction failed."));
    };
  });
}

export function downloadProjectFile(source: string, fileName: string): void {
  const url = URL.createObjectURL(new Blob([source], { type: "application/json" }));
  const link = document.createElement("a");
  link.href = url;
  link.download = fileName;
  link.click();
  URL.revokeObjectURL(url);
}

export function readProjectFile(file: File): Promise<string> {
  return file.text();
}