'use strict';

var _slicedToArray = function () { function sliceIterator(arr, i) { var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"]) _i["return"](); } finally { if (_d) throw _e; } } return _arr; } return function (arr, i) { if (Array.isArray(arr)) { return arr; } else if (Symbol.iterator in Object(arr)) { return sliceIterator(arr, i); } else { throw new TypeError("Invalid attempt to destructure non-iterable instance"); } }; }(); /**
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          * @fileOverview Ensures that no imported module imports the linted module.
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          * @author Ben Mosher
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          */

var _ExportMap = require('../ExportMap');

var _ExportMap2 = _interopRequireDefault(_ExportMap);

var _moduleVisitor = require('eslint-module-utils/moduleVisitor');

var _moduleVisitor2 = _interopRequireDefault(_moduleVisitor);

var _docsUrl = require('../docsUrl');

var _docsUrl2 = _interopRequireDefault(_docsUrl);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

// todo: cache cycles / deep relationships for faster repeat evaluation
module.exports = {
  meta: {
    type: 'suggestion',
    docs: { url: (0, _docsUrl2.default)('no-cycle') },
    schema: [(0, _moduleVisitor.makeOptionsSchema)({
      maxDepth: {
        description: 'maximum dependency depth to traverse',
        type: 'integer',
        minimum: 1
      }
    })]
  },

  create: function (context) {
    const myPath = context.getFilename();
    if (myPath === '<text>') return {}; // can't cycle-check a non-file

    const options = context.options[0] || {};
    const maxDepth = options.maxDepth || Infinity;

    function checkSourceValue(sourceNode, importer) {
      const imported = _ExportMap2.default.get(sourceNode.value, context);

      if (importer.importKind === 'type') {
        return; // no Flow import resolution
      }

      if (imported == null) {
        return; // no-unresolved territory
      }

      if (imported.path === myPath) {
        return; // no-self-import territory
      }

      const untraversed = [{ mget: () => imported, route: [] }];
      const traversed = new Set();
      function detectCycle(_ref) {
        let mget = _ref.mget,
            route = _ref.route;

        const m = mget();
        if (m == null) return;
        if (traversed.has(m.path)) return;
        traversed.add(m.path);

        for (let _ref2 of m.imports) {
          var _ref3 = _slicedToArray(_ref2, 2);

          let path = _ref3[0];
          var _ref3$ = _ref3[1];
          let getter = _ref3$.getter;
          let source = _ref3$.source;

          if (path === myPath) return true;
          if (traversed.has(path)) continue;
          if (route.length + 1 < maxDepth) {
            untraversed.push({
              mget: getter,
              route: route.concat(source)
            });
          }
        }
      }

      while (untraversed.length > 0) {
        const next = untraversed.shift(); // bfs!
        if (detectCycle(next)) {
          const message = next.route.length > 0 ? `Dependency cycle via ${routeString(next.route)}` : 'Dependency cycle detected.';
          context.report(importer, message);
          return;
        }
      }
    }

    return (0, _moduleVisitor2.default)(checkSourceValue, context.options[0]);
  }
};

function routeString(route) {
  return route.map(s => `${s.value}:${s.loc.start.line}`).join('=>');
}
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