import { randomBytes } from "node:crypto";
import { mkdir, readFile, rename, rm, writeFile } from "node:fs/promises";
import path from "node:path";
import { isValidStorageKey, type StorageDriver } from "./types";

/** Yerel disk sürücüsü. Yazma atomiktir (geçici dosya + rename); yarım dosya servis edilmez. */
export function createLocalDriver(baseDir: string): StorageDriver {
  const root = path.resolve(baseDir);

  function resolve(key: string): string {
    if (!isValidStorageKey(key)) throw new Error(`Geçersiz depolama anahtarı: ${key}`);
    const full = path.resolve(root, key);
    if (!full.startsWith(root + path.sep)) throw new Error("Depolama kökü dışına çıkılamaz.");
    return full;
  }

  return {
    async put(key, data) {
      const full = resolve(key);
      await mkdir(path.dirname(full), { recursive: true, mode: 0o750 });
      const tmp = `${full}.${randomBytes(6).toString("hex")}.tmp`;
      await writeFile(tmp, data, { mode: 0o640 });
      await rename(tmp, full);
    },
    async get(key) {
      try {
        return await readFile(resolve(key));
      } catch (error) {
        if ((error as NodeJS.ErrnoException).code === "ENOENT") return null;
        throw error;
      }
    },
    async delete(key) {
      await rm(resolve(key), { force: true });
    },
  };
}