/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @format
 */

/**
 * Compares the output of flow_parser.js with esprima
 */

var esprima = require('esprima-fb');
var util = require('util');
var ast_types = require('./esprima_ast_types.js');

function new_env() {
  var diffs = {};
  var astTypesErrors = [];
  var pathsWithAstTypesErrors = {};
  var path = ['root'];
  return {
    push_path: path.push.bind(path),
    pop_path: path.pop.bind(path),
    path_level: function () {
      return path.length;
    },

    diff: function (type, expected, actual) {
      var path_str = path.join('.');
      diffs[path_str] = {
        path: path_str,
        type: type,
        expected: expected,
        actual: actual,
      };
    },

    /** If we see an ast types error at root.foo.bar then we record the
     * subpaths so that we don't rerun the ast types recursive check for root
     * or root.foo
     */
    ast_types_error: function () {
      var full_path = path.join('.');
      astTypesErrors.push(full_path);
      var p = path[0];
      pathsWithAstTypesErrors[p] = true;
      for (var i = 1; i < path.length; i++) {
        p += '.' + path[i];
        pathsWithAstTypesErrors[p] = true;
      }
    },

    should_run_ast_types: function () {
      var p = path.join('.');
      return pathsWithAstTypesErrors[p] !== true;
    },

    get_diffs: function () {
      return diffs;
    },

    get_ast_types_errors: function () {
      return astTypesErrors;
    },
  };
}

function diff_to_string(diff) {
  var expected_str = '';
  if (
    typeof diff.expected !== 'undefined' ||
    typeof diff.actual !== 'undefined'
  ) {
    expected_str = '. Expected ' + diff.expected + ', got ' + diff.actual;
  }
  return diff.path + ': ' + diff.type + expected_str;
}

function handleSpecialObjectCompare(esprima, flow, env) {
  // Source location special handling
  if (esprima.hasOwnProperty('start') && esprima.hasOwnProperty('end')) {
    // Esprima omits the source property
    if (!esprima.hasOwnProperty('source') && flow.source === null) {
      esprima.source = null;
    }
  }

  /** TYPE ANNOTATION COMPATIBILITY **/
  if (
    esprima.hasOwnProperty('typeAnnotation') &&
    typeof esprima.typeAnnotation == 'undefined'
  ) {
    esprima.typeAnnotation = null;
  }

  // Root object
  if (env.path_level() == 1) {
    // Ignore the errors property on flow
    delete flow.errors;
  }

  switch (esprima.type) {
    case 'TryStatement':
      // The Mozilla spec changed over time. There used to be a "handlers"
      // property with a list of catch clauses. Now there is just a single
      // "handler" property. Esprima still only supports the old spec. Flow
      // follows the new spec
      flow.handlers = flow.handler ? [flow.handler] : [];
      flow.guardedHandlers = [];
      delete flow.handler;
      break;
    case 'Identifier':
      if (esprima.optional === undefined) {
        esprima.optional = false;
      }
      break;
    case 'FunctionDeclaration':
    case 'FunctionExpression':
      // Some more type annotation stuff missing from esprima
      if (esprima.typeParameters === undefined) {
        esprima.typeParameters = null;
      }
      if (esprima.returnType === undefined) {
        esprima.returnType = null;
      }
      break;
    case 'JSXEmptyExpression':
      // The location for the empty JSX expression doesn't really matter. I'm
      // arbitrarily using the location of the {}, and esprima is arbitrarily
      // using the single column location immediately after the {}
      esprima.loc = flow.loc;
      break;
    case 'ObjectPattern':
      for (var i = 0; i < esprima.properties.length; i++) {
        var prop = esprima.properties[i];
        switch (prop.type) {
          case 'SpreadProperty':
            prop.type = 'RestElement';
            break;
        }
      }
      if (!esprima.hasOwnProperty('typeAnnotation')) {
        esprima.typeAnnotation = null;
      }
      break;
    case 'MethodDefinition':
      // Esprima uses "get"/"set"/"" instead of "get"/"set"/"init"
      if (esprima.kind == '') {
        esprima.kind = 'init';
      }
      esprima.decorators = [];
      break;
    case 'ClassExpression':
      // Should use null for missing node
      if (esprima.id === undefined) {
        esprima.id = null;
      }
      if (esprima.typeParameters === undefined) {
        esprima.typeParameters = null;
      }
      if (esprima.superTypeParameters === undefined) {
        esprima.superTypeParameters = null;
      }
      if (esprima.implements === undefined) {
        esprima.implements = [];
      }

      // Class Decorator are not part of esprima but supported by flow
      if (esprima.decorators === undefined) {
        esprima.decorators = [];
      }
      break;
    case 'ClassDeclaration':
      if (esprima.typeParameters === undefined) {
        esprima.typeParameters = null;
      }
      if (esprima.superTypeParameters === undefined) {
        esprima.superTypeParameters = null;
      }
      if (esprima.implements === undefined) {
        esprima.implements = [];
      }

      // Class Decorator are not part of esprima but supported by flow
      if (esprima.decorators === undefined) {
        esprima.decorators = [];
      }
      break;
    case 'ClassBody':
      // esprima-fb is pretty out of date here. The 4 kinds should be
      // "constructor", "method", "get" and "set"
      for (var i = 0; i < esprima.body.length; i++) {
        var body = esprima.body[i];
        if (body && body.type == 'MethodDefinition') {
          if (body.key.name === 'constructor') {
            body.kind = 'constructor';
          } else if (body.kind === 'init' || body.kind === '') {
            body.kind = 'method';
          }
        }
      }
      break;
    case 'ArrayPattern':
      // Esprima has the wrong node type for spread elements in an array pattern
      for (var i = 0; i < esprima.elements.length; i++) {
        if (
          esprima.elements[i] &&
          esprima.elements[i].type == 'SpreadElement'
        ) {
          esprima.elements[i].type = 'RestElement';
        }
      }
      if (!esprima.hasOwnProperty('typeAnnotation')) {
        esprima.typeAnnotation = null;
      }
      break;
    case 'FunctionTypeAnnotation':
      if (!esprima.hasOwnProperty('this')) {
        esprima.this = null;
      }
      break;
    case 'ObjectTypeAnnotation':
      esprima.exact = esprima.exact || false;
      delete flow.inexact;
      esprima.internalSlots = esprima.internalSlots || [];
      break;
    case 'ObjectTypeProperty':
      esprima.kind = 'init'; // esprima-fb doesn't support getters/setters
      esprima.static = esprima.static || false;
      break;
    case 'ObjectTypeIndexer':
    case 'ObjectTypeCallProperty':
      esprima.static = esprima.static || false;
      break;
    case 'ClassProperty':
      esprima.static = esprima.static || false;
      esprima.value = null;
      break;
    case 'ArrowFunctionExpression':
      esprima.returnType = null;
      esprima.typeParameters = null;
      break;
    case 'ImportSpecifier':
      if (esprima.id != null) {
        esprima.imported = esprima.id;
        delete esprima.id;
      }
      if (esprima.name != null) {
        esprima.local = esprima.name;
      } else {
        esprima.local = esprima.imported;
      }
      delete esprima.name;
      break;
    case 'ImportDefaultSpecifier':
    case 'ImportNamespaceSpecifier':
      esprima.local = esprima.id;
      delete esprima.id;
      break;
    case 'ExportSpecifier':
      if (esprima.id != null) {
        esprima.local = esprima.id;
        delete esprima.id;
      }
      if (esprima.name != null) {
        esprima.exported = esprima.name;
      } else {
        esprima.exported = esprima.local;
      }
      delete esprima.name;
      break;
    case 'ExportBatchSpecifier':
      esprima.name = esprima.name || null;
      break;

    // Esprima is out of date. Type params are no longer Identifier nodes.
    case 'TypeParameterDeclaration':
      for (var i = 0; i < esprima.params.length; i++) {
        var param = esprima.params[i];
        param.type = 'TypeParameter';
        param.bound = param.typeAnnotation || null;
        param.default = param.default || null;
        param.variance = param.variance || null;
        delete param.typeAnnotation;
        delete param.optional;
      }
    case 'CallExpression':
    case 'NewExpression':
      delete flow.typeArguments;
      break;
  }

  switch (esprima.type) {
    case 'FunctionDeclaration':
    case 'FunctionExpression':
    case 'ArrowFunctionExpression':
      // esprima-fb uses a "defaults" array that is parallel to the "params"
      // array. Flow and modern esprima use AssignmentPatterns within the
      // params array.
      if (Array.isArray(esprima.defaults) && Array.isArray(esprima.params)) {
        for (var i = 0; i < esprima.defaults.length; i++) {
          var left = esprima.params[i];
          var right = esprima.defaults[i];
          if (right !== undefined && right !== null) {
            var newParam = {
              type: 'AssignmentPattern',
              left: left,
              right: right,
            };
            if (left.loc && right.loc) {
              newParam.loc = {
                start: {
                  line: left.loc.start.line,
                  column: left.loc.start.column,
                },
                end: {
                  line: right.loc.end.line,
                  column: right.loc.end.column,
                },
              };
              if (left.loc.source) {
                newParam.loc.source = left.loc.source;
              }
            }
            if (left.range && right.range) {
              newParam.range = [left.range[0], right.range[1]];
            }
            esprima.params[i] = newParam;
          }
        }
        delete esprima.defaults;
      }

      // esprima-fb uses a "rest" property. Flow and modern esprima use
      // RestElement within the params array.
      if ('rest' in esprima) {
        if (esprima.rest !== undefined && esprima.rest !== null) {
          var arg = esprima.rest;
          var rest = {
            type: 'RestElement',
            argument: arg,
          };
          if (arg.loc) {
            rest.loc = {
              start: {
                line: arg.loc.start.line,
                column: arg.loc.start.column - 3, // HACKY!
              },
              end: arg.loc.end,
            };
            if (arg.loc.source) {
              rest.loc.source = arg.loc.source;
            }
          }
          if (arg.range) {
            rest.range = [arg.range[0] - 3, arg.range[1]]; // HACKY!
          }
          esprima.params.push(rest);
        }
        delete esprima.rest;
      }

      if (esprima.async === undefined) {
        esprima.async = false;
      }

      delete flow.predicate;
  }

  if (flow && flow.type) {
    switch (flow.type) {
      case 'JSXText':
        // Esprima represents JSX children string literals as Literal nodes
        flow.type = 'Literal';
        break;
      case 'ObjectTypeProperty':
      case 'ObjectTypeIndexer':
      case 'PropertyDefinition':
        delete flow.variance;
        break;
      case 'DeclareModule':
        delete flow.kind;
        break;
      case 'DeclareFunction':
        delete flow.predicate;
        break;
      case 'ImportSpecifier':
        delete flow.importKind;
        break;
      case 'ExpressionStatement':
        // esprima-fb doesn't support directives yet
        delete flow.directive;
        break;
    }
  }
}

function compare(esprima, flow, env) {
  var esprima_type = typeof esprima;
  var flow_type = typeof flow;
  if (esprima_type === 'object') {
    if (esprima === null) {
      esprima_type = 'null';
    } else if (Array.isArray(esprima)) {
      esprima_type = 'Array';
    }
  }
  if (flow_type === 'object') {
    if (flow === null) {
      flow_type = 'null';
    } else if (Array.isArray(flow)) {
      flow_type = 'Array';
    }
  }

  if (esprima_type != flow_type) {
    env.diff('Wrong type', esprima_type, flow_type);
    return;
  }
  if (esprima_type == 'string') {
    if (esprima !== flow) {
      env.diff('Wrong string', esprima, flow);
    }
  } else if (esprima_type == 'number') {
    if (esprima !== flow) {
      env.diff('Wrong number', esprima, flow);
    }
  } else if (esprima_type == 'boolean') {
    if (esprima !== flow) {
      env.diff('Wrong boolean', esprima, flow);
    }
  } else if (esprima_type == 'Array') {
    if (esprima.length !== flow.length) {
      env.diff('Wrong array length', esprima.length, flow.length);
    } else {
      for (var i = 0; i < esprima.length; i++) {
        env.push_path(i);
        compare(esprima[i], flow[i], env);
        env.pop_path();
      }
    }
  } else if (esprima === null) {
    if (esprima !== flow) {
      env.diff('Wrong null', esprima, flow);
    }
  } else if (esprima instanceof RegExp) {
    if (!(flow instanceof RegExp)) {
      env.diff('type', 'RegExp', flow_type);
      return;
    }
    if (String(esprima) != String(flow)) {
      env.diff('Wrong RegExp', String(esprima), String(flow));
      return;
    }
  } else if (esprima_type == 'object') {
    handleSpecialObjectCompare(esprima, flow, env);
    for (var prop in esprima) {
      if (!esprima.hasOwnProperty(prop)) {
        continue;
      }
      env.push_path(prop);
      if (!flow || !flow.hasOwnProperty(prop)) {
        env.diff('Missing property');
      } else {
        compare(esprima[prop], flow[prop], env);
      }
      env.pop_path();
    }
    for (var prop in flow) {
      if (flow.hasOwnProperty(prop) && !esprima.hasOwnProperty(prop)) {
        env.push_path(prop);
        env.diff('Unexpected property');
        env.pop_path();
      }
    }
  }

  if (flow && flow_type == 'object' && flow.hasOwnProperty('type')) {
    if (env.should_run_ast_types()) {
      if (!ast_types.namedTypes[flow.type]) {
        env.diff('Unknown AST type', 'known type', flow.type);
      } else if (!ast_types.namedTypes[flow.type].check(flow, true)) {
        throw new Error(
          `${ast_types.namedTypes[flow.type]} ${JSON.stringify(flow)}`,
        );
        env.ast_types_error();
      }
    }
  }
}

function runTest(test, esprima_options, test_options) {
  var env = new_env();
  var comparing_errors = false;
  var result = {
    passed: true,
    output: '',
  };
  function output() {
    for (var i = 0; i < arguments.length; i++) {
      result.output += arguments[i] + ' ';
    }
    result.output += '\n';
  }
  try {
    var flow_ast = test_options.flow.parse(test.content, {});
  } catch (e) {
    output('Flow exploded:', util.inspect(e, {depth: null}));
    result.passed = false;
    return result;
  }
  var options = {loc: true, comment: true, range: true};
  for (var opt in esprima_options) {
    options[opt] = esprima_options[opt];
  }
  try {
    var esprima_ast = esprima.parse(test.content, options);
  } catch (e) {
    comparing_errors = true;
    if (test_options.dumpAst) {
      console.log(
        'Esprima AST: ',
        util.inspect(e, {depth: null, colors: true}),
      );
      console.log(
        'Flow AST: ',
        util.inspect(flow_ast, {depth: null, colors: true}),
      );
      output('Esprima AST: ', util.inspect(e, {depth: null, colors: true}));
      output('Flow AST: ', util.inspect(flow_ast, {depth: null, colors: true}));
    }

    var errors = flow_ast.errors || [];
    env.push_path('errors');
    if (errors.length > 0) {
      // Errors seem to be 1-indexed for columns in esprima's errors
      env.push_path('0');
      if (
        errors[0].loc.start.column > e.column - 1 ||
        e.column - 1 > errors[0].loc.end.column
      ) {
        env.push_path('column');
        env.diff(
          'Wrong error column',
          e.column - 1,
          errors[0].loc.start.column + '-' + errors[0].loc.end.column,
        );
        env.pop_path();
      }
      if (
        errors[0].loc.start.line > e.lineNumber ||
        e.lineNumber > errors[0].loc.end.line
      ) {
        env.push_path('line');
        env.diff(
          'Wrong error line',
          e.lineNumber,
          errors[0].loc.start.line + '-' + errors[0].loc.end.line,
        );
        env.pop_path();
      }
      if (errors[0].message != e.description) {
        env.push_path('message');
        env.diff('Wrong error message', e.description, errors[0].message);
        env.pop_path();
      }
      env.pop_path();
    } else {
      env.diff('Flow found no error', e.message);
    }
    env.pop_path();
  }

  // Some checks that we only run when comparing asts
  if (!comparing_errors) {
    if (test_options.dumpAst) {
      console.log(
        'Esprima AST: ',
        util.inspect(esprima_ast, {depth: null, colors: true}),
      );
      console.log(
        'Flow AST: ',
        util.inspect(flow_ast, {depth: null, colors: true}),
      );
      output(
        'Esprima AST: ',
        util.inspect(esprima_ast, {depth: null, colors: true}),
      );
      output('Flow AST: ', util.inspect(flow_ast, {depth: null, colors: true}));
    }
    var flow_errors = flow_ast.errors;
    compare(esprima_ast, flow_ast, env);

    if (flow_errors.length !== 0) {
      env.push_path('errors');
      for (var i = 0; i < flow_errors.length; i++) {
        var e = flow_errors[i];
        env.push_path(i);
        env.push_path('column');
        env.diff('Wrong error column', undefined, e.loc.start.column + 1);
        env.pop_path();
        env.push_path('line');
        env.diff('Wrong error line', undefined, e.loc.start.line);
        env.pop_path();
        env.push_path('message');
        env.diff('Wrong error message', undefined, e.message);
        env.pop_path();
      }
      env.pop_path();
    }

    var ast_types_errors = env.get_ast_types_errors();
    if (ast_types_errors.length !== 0) {
      result.passed = false;
      output('****AST Types Errors****');
      for (var i = 0; i < ast_types_errors.length; i++) {
        output('(#' + i + ')', ast_types_errors[i]);
      }
    }
  }

  if (test_options.showDifferences) {
    test.expected_differences = {};
    output(test.explanation || 'No explanation provided');
  }

  var actual = env.get_diffs();
  var expected = test.expected_differences || {};
  var missing_diffs = [];
  var unexpected_differences = [];
  var mismatched_diffs = [];
  for (var path in expected) {
    if (!expected.hasOwnProperty(path)) {
      continue;
    }

    if (path in actual) {
      if (
        actual[path].type != expected[path].type ||
        actual[path].expected != expected[path].expected ||
        actual[path].actual != expected[path].actual
      ) {
        expected[path].path = path;
        mismatched_diffs.push({expected: expected[path], actual: actual[path]});
      }
    } else {
      expected[path].path = path;
      missing_diffs.push(expected[path]);
    }
  }

  for (var path in actual) {
    if (actual.hasOwnProperty(path) && !expected.hasOwnProperty(path)) {
      unexpected_differences.push(actual[path]);
    }
  }

  if (test_options.jsonErrors) {
    diff_to_string = function (e) {
      return util.inspect(e, {depth: null});
    };
  }
  if (missing_diffs.length > 0) {
    result.passed = false;
    output('****Missing Expected Differences****');
    for (var i = 0; i < missing_diffs.length; i++) {
      output('(#' + i + ')', diff_to_string(missing_diffs[i]));
    }
  }
  if (unexpected_differences.length > 0) {
    result.passed = false;
    output('****Unexpected Differences****');
    for (var i = 0; i < unexpected_differences.length; i++) {
      output('(#' + i + ')', diff_to_string(unexpected_differences[i]));
    }
  }
  if (mismatched_diffs.length > 0) {
    result.passed = false;
    output('****Mismatched Differences****');
    for (var i = 0; i < mismatched_diffs.length; i++) {
      output(
        '(#' + i + ') Expected ',
        diff_to_string(mismatched_diffs[i].expected),
      );
      output(
        '(#' + i + ') Actual ',
        diff_to_string(mismatched_diffs[i].actual),
      );
    }
  }
  return result;
}

module.exports = runTest;
