var acorn = require('acorn')
var xtend = require('xtend')

// acorn-node@1.x expects acorn@7+ which provides a static `Parser.extend`.
// Some dependency trees (like this Pulsar package) end up with an older acorn
// that only exposes the Parser constructor without the `extend` helper.
//
// Provide a small polyfill so acorn-node can load and operate.
if (acorn && acorn.Parser && typeof acorn.Parser.extend !== 'function') {
  var ensureParserStatics = function (ParserCtor) {
    if (!ParserCtor) return

    if (typeof ParserCtor.parse !== 'function') {
      ParserCtor.parse = function (input, options) {
        return new ParserCtor(options, input).parse()
      }
    }

    if (typeof ParserCtor.parseExpressionAt !== 'function') {
      ParserCtor.parseExpressionAt = function (input, pos, options) {
        var p = new ParserCtor(options, input, pos)
        p.nextToken()
        return p.parseExpression()
      }
    }

    if (typeof ParserCtor.tokenizer !== 'function') {
      ParserCtor.tokenizer = function (input, options) {
        return new ParserCtor(options, input)
      }
    }
  }

  var extend = function () {
    var Parser = this
    for (var i = 0; i < arguments.length; i++) {
      var plugin = arguments[i]
      if (plugin && typeof plugin !== 'function' && typeof plugin.default === 'function') {
        plugin = plugin.default
      }
      if (typeof plugin === 'function') {
        Parser = plugin(Parser)
        Parser.extend = extend
        ensureParserStatics(Parser)
      }
    }
    return Parser
  }

  acorn.Parser.extend = extend
  ensureParserStatics(acorn.Parser)
}

var CJSParser = acorn.Parser
  .extend(require('./lib/bigint'))
  .extend(require('./lib/class-fields'))
  .extend(require('./lib/static-class-features'))
  .extend(require('./lib/numeric-separator'))
  .extend(require('./lib/dynamic-import').default)
var ESModulesParser = CJSParser
  .extend(require('./lib/export-ns-from'))
  .extend(require('./lib/import-meta'))

function mapOptions (opts) {
  if (!opts) opts = {}
  return xtend({
    ecmaVersion: 2020,
    allowHashBang: true,
    allowReturnOutsideFunction: true
  }, opts)
}

function getParser (opts) {
  if (!opts) opts = {}
  return opts.sourceType === 'module' ? ESModulesParser : CJSParser
}

module.exports = exports = xtend(acorn, {
  parse: function parse (src, opts) {
    return getParser(opts).parse(src, mapOptions(opts))
  },
  parseExpressionAt: function parseExpressionAt (src, offset, opts) {
    return getParser(opts).parseExpressionAt(src, offset, mapOptions(opts))
  },
  tokenizer: function tokenizer (src, opts) {
    return getParser(opts).tokenizer(src, mapOptions(opts))
  }
})