import hasha from 'hasha';

function getLeafId(nodePath) {
  return hasha(nodePath.join('#'), { algorithm: 'sha256', encoding: 'hex' });
}

async function dbWrapper(client, dbName) {
  try {
    await client.db.get(dbName);
  } catch (e) {
    await client.db.create(dbName);
  }
  const db = await client.use(dbName);
  return {
    get: async function get(nodePath, callback) {
      const contentId = getLeafId(nodePath);
      db.get(contentId, (err, reply) => {
        if (err) {
          callback(null);
        } else {
          callback(reply);
        }
      });
    },
    set: async function set(nodePath, data, callback) {
      const contentId = getLeafId(nodePath);
      db.get(contentId, (getError, existingDoc) => {
        if (getError) {
          db.insert({ ...data, _id: contentId }, (insertNewError, reply) => {
            if (insertNewError) {
              throw new Error(insertNewError);
            } else if (callback) {
              callback(reply);
            }
          });
        } else {
          db.insert({ ...data, _id: contentId, _rev: existingDoc._rev }, (updateError, reply) => {
            if (updateError) {
              throw new Error(updateError);
            } else if (callback) {
              callback(reply);
            }
          });
        }
      });
    },
  };
}

export default dbWrapper;