text: const t = require('babel-types');
  const Path = require('path');
  const fs = require('fs');
  const template = require('babel-template');
  const logger = require('../Logger');
  
  const bufferTemplate = template('Buffer(CONTENT, ENC)');
  
  module.exports = {
    AssignmentExpression(path) {
      if (!isRequire(path.node.right, 'fs', 'readFileSync')) {
        return;
      }
  
      for (let name in path.getBindingIdentifiers()) {
        const binding = path.scope.getBinding(name);
        if (!binding) continue;
  
        binding.path.setData('__require', path.node);
      }
    },
  
    CallExpression(path, asset) {
      if (referencesImport(path, 'fs', 'readFileSync')) {
        let vars = {
          __dirname: Path.dirname(asset.name),
          __filename: asset.basename
        };
        let filename, args, res;
  
        try {
          [filename, ...args] = path
            .get('arguments')
            .map(arg => evaluate(arg, vars));
  
          filename = Path.resolve(filename);
          res = fs.readFileSync(filename, ...args);
        } catch (err) {
          if (err instanceof NodeNotEvaluatedError) {
            // Warn using a code frame
            err.fileName = asset.name;
            asset.generateErrorMessage(err);
            logger.warn(err);
            return;
          }
  
          // Add location info so we log a code frame with the error
          err.loc =
            path.node.arguments.length > 0
              ? path.node.arguments[0].loc.start
              : path.node.loc.start;
          throw err;
        }
  
        let replacementNode;
        if (Buffer.isBuffer(res)) {
          replacementNode = bufferTemplate({
            CONTENT: t.stringLiteral(res.toString('base64')),
            ENC: t.stringLiteral('base64')
          });
        } else {
          replacementNode = t.stringLiteral(res);
        }
  
        asset.addDependency(filename, {includedInParent: true});
        path.replaceWith(replacementNode);
        asset.isAstDirty = true;
      }
    }
  };
  
  function isRequire(node, name, method) {
    // e.g. require('fs').readFileSync
    if (t.isMemberExpression(node) && node.property.name === method) {
      node = node.object;
    }
  
    if (!t.isCallExpression(node)) {
      return false;
    }
  
    let {callee, arguments: args} = node;
    let isRequire =
      t.isIdentifier(callee) &&
      callee.name === 'require' &&
      args.length === 1 &&
      t.isStringLiteral(args[0]);
  
    if (!isRequire) {
      return false;
    }
  
    if (name && args[0].value !== name) {
      return false;
    }
  
    return true;
  }
  
  function referencesImport(path, name, method) {
    let callee = path.node.callee;
    let bindingPath;
  
    // e.g. readFileSync()
    if (t.isIdentifier(callee)) {
      bindingPath = getBindingPath(path, callee.name);
    } else if (t.isMemberExpression(callee)) {
      if (callee.property.name !== method) {
        return false;
      }
  
      // e.g. fs.readFileSync()
      if (t.isIdentifier(callee.object)) {
        bindingPath = getBindingPath(path, callee.object.name);
  
        // require('fs').readFileSync()
      } else if (isRequire(callee.object, name)) {
        return true;
      }
    } else {
      return false;
    }
  
    if (!bindingPath) {
      return;
    }
  
    let bindingNode = bindingPath.getData('__require') || bindingPath.node;
    let parent = bindingPath.parentPath;
  
    // e.g. import fs from 'fs';
    if (parent.isImportDeclaration()) {
      if (
        bindingPath.isImportSpecifier() &&
        bindingPath.node.imported.name !== method
      ) {
        return false;
      }
  
      return parent.node.source.value === name;
  
      // e.g. var fs = require('fs');
    } else if (
      t.isVariableDeclarator(bindingNode) ||
      t.isAssignmentExpression(bindingNode)
    ) {
      let left = bindingNode.id || bindingNode.left;
      let right = bindingNode.init || bindingNode.right;
  
      // e.g. var {readFileSync} = require('fs');
      if (t.isObjectPattern(left)) {
        let prop = left.properties.find(p => p.value.name === callee.name);
        if (!prop || prop.key.name !== method) {
          return false;
        }
      } else if (!t.isIdentifier(left)) {
        return false;
      }
  
      return isRequire(right, name, method);
    }
  
    return false;
  }
  
  function getBindingPath(path, name) {
    let binding = path.scope.getBinding(name);
    return binding && binding.path;
  }
  
  function NodeNotEvaluatedError(node) {
    this.message = 'Cannot statically evaluate fs argument';
    this.node = node;
    this.loc = node.loc.start;
  }
  
  function evaluate(path, vars) {
    // Inline variables
    path.traverse({
      Identifier: function(ident) {
        let key = ident.node.name;
        if (key in vars) {
          ident.replaceWith(t.valueToNode(vars[key]));
        }
      }
    });
  
    let res = path.evaluate();
  
    if (!res.confident) {
      throw new NodeNotEvaluatedError(path.node);
    }
  
    return res.value;
  }
  