function transform(file, { j }, options) {
  const root = j(file.source);
  const { identifier } = replaceDefaultImport(
    'md5',
    'crypto',
    'crypto',
    root,
    j
  );

  // Replace function calls
  root
    .find(j.CallExpression, {
      callee: { name: identifier }
    })
    .forEach((path) => {
      const newExpression = j.callExpression(
        j.memberExpression(
          j.callExpression(
            j.memberExpression(
              j.callExpression(
                j.memberExpression(
                  j.identifier('crypto'),
                  j.identifier('createHash')
                ),
                [j.literal('md5')]
              ),
              j.identifier('update')
            ),
            path.node.arguments
          ),
          j.identifier('digest')
        ),
        [j.literal('hex')]
      );
      j(path).replaceWith(newExpression);
    });

  return root.toSource(options);
}

export function replaceDefaultImport(name, newSpecifier, newName, root, j) {
  const importDeclaration = root.find(j.ImportDeclaration, {
    source: {
      value: name
    }
  });

  const requireDeclaration = root.find(j.VariableDeclarator, {
    init: {
      callee: {
        name: 'require'
      },
      arguments: [
        {
          value: name
        }
      ]
    }
  });

  const identifier =
    importDeclaration.paths().length > 0
      ? importDeclaration.get().node.specifiers[0].local.name
      : requireDeclaration.paths().length > 0
        ? requireDeclaration.find(j.Identifier).get().node.name
        : null;

  importDeclaration.forEach((path) => {
    j(path).replaceWith(
      j.importDeclaration(
        [j.importDefaultSpecifier(j.identifier(newSpecifier))],
        j.stringLiteral(newName)
      )
    );
  });

  requireDeclaration.forEach((path) => {
    const newExpression = j.assignmentExpression(
      '=',
      j.identifier(newSpecifier),
      j.callExpression(j.identifier('require'), [j.literal(newName)])
    );
    j(path).replaceWith(newExpression);
  });

  return { identifier };
}

export default transform;