export default function transformer(file, api) {
  const j = api.jscodeshift;
  const root = j(file.source);

  const getClockMocker = j.variableDeclaration('const', [
    j.variableDeclarator(
      j.identifier('clock'),
      j.callExpression(j.identifier('ClockMocker.getClock'), [])
    )
  ]);

  const nextClockMocker = j.expressionStatement(j.callExpression(j.identifier('clock.next'), []));

  const uninstallClockMocker = j.expressionStatement(
    j.callExpression(j.identifier('ClockMocker.uninstall'), [])
  );

  const tests = root.find(j.CallExpression, {
    callee: {
      name: 'it'
    }
  });

  tests.forEach(test => {
    const blockStatement = test.value.arguments[1].body;
    const waitForReactRerenderFunctions = j(blockStatement).find(j.CallExpression, {
      callee: {
        name: 'waitForReactRerender'
      }
    });

    if (waitForReactRerenderFunctions.paths().length > 0) {
      // remove waitForReactRerender import
      root
        .find(j.ImportDefaultSpecifier, { local: { name: 'waitForReactRerender' } })
        .forEach(path => j(path.parentPath.parentPath).remove());

      // add ClockMocker import if needed
      if (root.find(j.ImportDefaultSpecifier, { local: { name: 'ClockMocker' } }).length === 0) {
        const cmImport = j.importDeclaration(
          [j.importDefaultSpecifier(j.identifier('ClockMocker'))],
          j.literal('test/testUtilities/ClockMocker')
        );
        root
          .find(j.Program)
          .get('body')
          .get(0)
          .insertBefore(cmImport);
      }

      const blockBody = j(blockStatement).get('body');
      blockBody.get(0).insertBefore(getClockMocker);

      blockBody.get(blockBody.value.length - 1).insertAfter(uninstallClockMocker);

      //make test sync
      j(test)
        .find(j.Identifier, { name: 'done' })
        .remove();
    }
    let FunctionContents = new Map();
    waitForReactRerenderFunctions.forEach(path => {
      // add clock.next(); to the beginning of each function
      j(path.value.arguments).forEach(arg => {
        const funcBody = j(arg).get('body');
        if (funcBody.value) {
          const existingValue = FunctionContents.get(path.parentPath) || [];
          FunctionContents.set(path.parentPath, [
            ...existingValue,
            nextClockMocker,
            ...funcBody.value.body
          ]);
        }
      });
    });
    FunctionContents.forEach((values, key) =>
      values.reverse().forEach(value => key.insertAfter(value))
    );
    waitForReactRerenderFunctions.remove();
  });

  return root.toSource();
}