/**
   * @fileoverview Define 2 token factories; forward and backward.
   * @author Toru Nagashima
   */
  "use strict";
  
  //------------------------------------------------------------------------------
  // Requirements
  //------------------------------------------------------------------------------
  
  const BackwardTokenCommentCursor = require("./backward-token-comment-cursor");
  const BackwardTokenCursor = require("./backward-token-cursor");
  const FilterCursor = require("./filter-cursor");
  const ForwardTokenCommentCursor = require("./forward-token-comment-cursor");
  const ForwardTokenCursor = require("./forward-token-cursor");
  const LimitCursor = require("./limit-cursor");
  const SkipCursor = require("./skip-cursor");
  
  //------------------------------------------------------------------------------
  // Helpers
  //------------------------------------------------------------------------------
  
  /**
   * The cursor factory.
   * @private
   */
  class CursorFactory {
  
      /**
       * Initializes this cursor.
       * @param {Function} TokenCursor - The class of the cursor which iterates tokens only.
       * @param {Function} TokenCommentCursor - The class of the cursor which iterates the mix of tokens and comments.
       */
      constructor(TokenCursor, TokenCommentCursor) {
          this.TokenCursor = TokenCursor;
          this.TokenCommentCursor = TokenCommentCursor;
      }
  
      /**
       * Creates a base cursor instance that can be decorated by createCursor.
       *
       * @param {Token[]} tokens - The array of tokens.
       * @param {Comment[]} comments - The array of comments.
       * @param {Object} indexMap - The map from locations to indices in `tokens`.
       * @param {number} startLoc - The start location of the iteration range.
       * @param {number} endLoc - The end location of the iteration range.
       * @param {boolean} includeComments - The flag to iterate comments as well.
       * @returns {Cursor} The created base cursor.
       */
      createBaseCursor(tokens, comments, indexMap, startLoc, endLoc, includeComments) {
          const Cursor = includeComments ? this.TokenCommentCursor : this.TokenCursor;
  
          return new Cursor(tokens, comments, indexMap, startLoc, endLoc);
      }
  
      /**
       * Creates a cursor that iterates tokens with normalized options.
       *
       * @param {Token[]} tokens - The array of tokens.
       * @param {Comment[]} comments - The array of comments.
       * @param {Object} indexMap - The map from locations to indices in `tokens`.
       * @param {number} startLoc - The start location of the iteration range.
       * @param {number} endLoc - The end location of the iteration range.
       * @param {boolean} includeComments - The flag to iterate comments as well.
       * @param {Function|null} filter - The predicate function to choose tokens.
       * @param {number} skip - The count of tokens the cursor skips.
       * @param {number} count - The maximum count of tokens the cursor iterates. Zero is no iteration for backward compatibility.
       * @returns {Cursor} The created cursor.
       */
      createCursor(tokens, comments, indexMap, startLoc, endLoc, includeComments, filter, skip, count) {
          let cursor = this.createBaseCursor(tokens, comments, indexMap, startLoc, endLoc, includeComments);
  
          if (filter) {
              cursor = new FilterCursor(cursor, filter);
          }
          if (skip >= 1) {
              cursor = new SkipCursor(cursor, skip);
          }
          if (count >= 0) {
              cursor = new LimitCursor(cursor, count);
          }
  
          return cursor;
      }
  }
  
  //------------------------------------------------------------------------------
  // Exports
  //------------------------------------------------------------------------------
  
  exports.forward = new CursorFactory(ForwardTokenCursor, ForwardTokenCommentCursor);
  exports.backward = new CursorFactory(BackwardTokenCursor, BackwardTokenCommentCursor);