'use strict';

var acorn = require('acorn'); var walk = require('acorn/dist/walk');

function isScope(node) {

return node.type === 'FunctionExpression' || node.type === 'FunctionDeclaration' || node.type === 'ArrowFunctionExpression' || node.type === 'Program';

} function isBlockScope(node) {

return node.type === 'BlockStatement' || isScope(node);

}

function declaresArguments(node) {

return node.type === 'FunctionExpression' || node.type === 'FunctionDeclaration';

}

function declaresThis(node) {

return node.type === 'FunctionExpression' || node.type === 'FunctionDeclaration';

}

function reallyParse(source) {

return acorn.parse(source, {
  allowReturnOutsideFunction: true,
  allowImportExportEverywhere: true,
  allowHashBang: true
});

} module.exports = findGlobals; module.exports.parse = reallyParse; function findGlobals(source) {

var globals = [];
var ast;
// istanbul ignore else
if (typeof source === 'string') {
  ast = reallyParse(source);
} else {
  ast = source;
}
// istanbul ignore if
if (!(ast && typeof ast === 'object' && ast.type === 'Program')) {
  throw new TypeError('Source must be either a string of JavaScript or an acorn AST');
}
var declareFunction = function (node) {
  var fn = node;
  fn.locals = fn.locals || {};
  node.params.forEach(function (node) {
    declarePattern(node, fn);
  });
  if (node.id) {
    fn.locals[node.id.name] = true;
  }
}
var declarePattern = function (node, parent) {
  switch (node.type) {
    case 'Identifier':
      parent.locals[node.name] = true;
      break;
    case 'ObjectPattern':
      node.properties.forEach(function (node) {
        declarePattern(node.value, parent);
      });
      break;
    case 'ArrayPattern':
      node.elements.forEach(function (node) {
        if (node) declarePattern(node, parent);
      });
      break;
    case 'RestElement':
      declarePattern(node.argument, parent);
      break;
    case 'AssignmentPattern':
      declarePattern(node.left, parent);
      break;
    // istanbul ignore next
    default:
      throw new Error('Unrecognized pattern type: ' + node.type);
  }
}
var declareModuleSpecifier = function (node, parents) {
  ast.locals = ast.locals || {};
  ast.locals[node.local.name] = true;
}
walk.ancestor(ast, {
  'VariableDeclaration': function (node, parents) {
    var parent = null;
    for (var i = parents.length - 1; i >= 0 && parent === null; i--) {
      if (node.kind === 'var' ? isScope(parents[i]) : isBlockScope(parents[i])) {
        parent = parents[i];
      }
    }
    parent.locals = parent.locals || {};
    node.declarations.forEach(function (declaration) {
      declarePattern(declaration.id, parent);
    });
  },
  'FunctionDeclaration': function (node, parents) {
    var parent = null;
    for (var i = parents.length - 2; i >= 0 && parent === null; i--) {
      if (isScope(parents[i])) {
        parent = parents[i];
      }
    }
    parent.locals = parent.locals || {};
    parent.locals[node.id.name] = true;
    declareFunction(node);
  },
  'Function': declareFunction,
  'ClassDeclaration': function (node, parents) {
    var parent = null;
    for (var i = parents.length - 2; i >= 0 && parent === null; i--) {
      if (isScope(parents[i])) {
        parent = parents[i];
      }
    }
    parent.locals = parent.locals || {};
    parent.locals[node.id.name] = true;
  },
  'TryStatement': function (node) {
    if (node.handler === null) return;
    node.handler.locals = node.handler.locals || {};
    node.handler.locals[node.handler.param.name] = true;
  },
  'ImportDefaultSpecifier': declareModuleSpecifier,
  'ImportSpecifier': declareModuleSpecifier,
  'ImportNamespaceSpecifier': declareModuleSpecifier
});
function identifier(node, parents) {
  var name = node.name;
  if (name === 'undefined') return;
  for (var i = 0; i < parents.length; i++) {
    if (name === 'arguments' && declaresArguments(parents[i])) {
      return;
    }
    if (parents[i].locals && name in parents[i].locals) {
      return;
    }
  }
  node.parents = parents;
  globals.push(node);
}
walk.ancestor(ast, {
  'VariablePattern': identifier,
  'Identifier': identifier,
  'ThisExpression': function (node, parents) {
    for (var i = 0; i < parents.length; i++) {
      if (declaresThis(parents[i])) {
        return;
      }
    }
    node.parents = parents;
    globals.push(node);
  }
});
var groupedGlobals = {};
globals.forEach(function (node) {
  var name = node.type === 'ThisExpression' ? 'this' : node.name;
  groupedGlobals[name] = (groupedGlobals[name] || []);
  groupedGlobals[name].push(node);
});
return Object.keys(groupedGlobals).sort().map(function (name) {
  return {name: name, nodes: groupedGlobals[name]};
});

}