const parse = require('@babel/parser').parse;
const traverse = require('@babel/traverse').default;
const generate = require('@babel/generator').default;
const types = require('@babel/types');

module.exports = function transformNodeEnvInline(file) {
 // if (file.subpath !== '/node_modules/mobx/lib/index.js') {
 // return;
 // }

 if (!file.isJsLike || !file.isMod) {
 return;
 }

 let contents = file.getContent();
 const idx = contents.indexOf('process.env.NODE_ENV');
 if (idx === -1) {
 return;
 }

 const idx2 = contents.indexOf('require(', idx);
 if (idx2 === -1) {
 return;
 }

 const env = file.optimizer ? 'production' : 'development';

 contents = contents.replace(/typeof\s+process\b/g, () =>
 JSON.stringify('object')
 );
 const ast = parse(contents, {
 sourceType: 'module'
 });

 traverse(ast, {
 // 参考: https://www.trickster.dev/post/javascript-ast-manipulation-with-babel-removing-unreachable-code/
 // 参考:https://github.com/babel/minify/blob/master/packages/babel-plugin-transform-node-env-inline/src/index.js
 MemberExpression(path) {
 if (path.matchesPattern('process.env.NODE_ENV')) {
 path.replaceWith(types.valueToNode(env));
 let parentPath = path.parentPath;
 if (parentPath.isBinaryExpression()) {
 const evaluated = parentPath.evaluate();
 if (evaluated.confident) {
 parentPath.replaceWith(types.valueToNode(evaluated.value));
 }
 }

 let ifStatement = null;
 while (parentPath) {
 if (
 parentPath.isIfStatement() ||
 parentPath.isConditionalExpression()
 ) {
 ifStatement = parentPath;
 }

 parentPath = parentPath.parentPath;
 }

 if (ifStatement) {
 let isTruthy = ifStatement.get('test').evaluateTruthy();
 const node = ifStatement.node;

 if (isTruthy) {
 if (types.isBlockStatement(node.consequent)) {
 ifStatement.replaceWithMultiple(node.consequent.body);
 } else {
 ifStatement.replaceWith(node.consequent);
 }
 } else if (node.alternate != null) {
 if (types.isBlockStatement(node.alternate)) {
 ifStatement.replaceWithMultiple(node.alternate.body);
 } else {
 ifStatement.replaceWith(node.alternate);
 }
 } else {
 ifStatement.remove();
 }
 }
 }
 }
 });

 contents = generate(ast, {}).code;
 file.setContent(contents);

 // console.log('\n', file.subpath, '\n', file.getContent());
 // process.exit(1);
};