/**
 * Modified from https://github.com/skratchdot/amd-to-commonjs-codemod
 */

const buildRequire = (j, v, r) => {
  let code = "";
  if (v && v.type === "Identifier" && v.name.length) {
    code += `const ${v.name}`;
  }
  if (r && r.type === "Literal" && r.value.length) {
    if (code.length) {
      code += " = ";
    }
    code += `require('${r.value}')`;
  }
  code += ";";
  if (code === ";") {
    code = "";
  }
  return code;
};

module.exports = function(file, api) {
  const j = api.jscodeshift;
  return j(file.source)
    .find(j.CallExpression)
    .filter(
      path =>
        path.parentPath.parentPath.node.type === "Program" &&
        path.parentPath.node.type === "ExpressionStatement" &&
        path.node.type === "CallExpression" &&
        path.node.callee.type === "Identifier" &&
        path.node.callee.name === "define" &&
        path.node.arguments.length === 2 &&
        path.node.arguments[0].type === "ArrayExpression" &&
        ["FunctionExpression", "ArrowFunctionExpression"].indexOf(path.node.arguments[1].type) >= 0
    )
    .replaceWith(path => {
      const arrayExpression = path.node.arguments[0];
      const functionExpression = path.node.arguments[1];
      const comments = path.node.comments;
      const result = [];
      const statementSize = Math.max(functionExpression.params.length, arrayExpression.elements.length);
      for (let i = 0; i < statementSize; i++) {
        result.push(buildRequire(j, functionExpression.params[i], arrayExpression.elements[i]));
      }
      let spliceIndex = functionExpression.body.body.findIndex(
        bodyNode => bodyNode.type !== "ExpressionStatement" || bodyNode.expression.type !== "Literal"
      );
      functionExpression.body.body.splice(spliceIndex, 0, ...result);
      functionExpression.params = [];
      var returnValue;
      if (functionExpression.body.body.some(bodyNode => bodyNode.type === "ReturnStatement")) {
        returnValue = j.assignmentExpression(
          "=",
          j.memberExpression(j.identifier("module"), j.identifier("exports")),
          j.callExpression(functionExpression, [])
        );
      } else {
        returnValue = j.callExpression(functionExpression, []);
      }
      returnValue.comments = path.node.comments;
      return returnValue;
    })
    .toSource();
};