/**
   * @fileoverview Rule to enforce a single linebreak style.
   * @author Erik Mueller
   */
  
  "use strict";
  
  //------------------------------------------------------------------------------
  // Requirements
  //------------------------------------------------------------------------------
  
  const astUtils = require("../ast-utils");
  
  //------------------------------------------------------------------------------
  // Rule Definition
  //------------------------------------------------------------------------------
  
  module.exports = {
      meta: {
          docs: {
              description: "enforce consistent linebreak style",
              category: "Stylistic Issues",
              recommended: false
          },
  
          fixable: "whitespace",
  
          schema: [
              {
                  enum: ["unix", "windows"]
              }
          ]
      },
  
      create(context) {
  
          const EXPECTED_LF_MSG = "Expected linebreaks to be 'LF' but found 'CRLF'.",
              EXPECTED_CRLF_MSG = "Expected linebreaks to be 'CRLF' but found 'LF'.";
  
          const sourceCode = context.getSourceCode();
  
          //--------------------------------------------------------------------------
          // Helpers
          //--------------------------------------------------------------------------
  
          /**
           * Builds a fix function that replaces text at the specified range in the source text.
           * @param {int[]} range The range to replace
           * @param {string} text The text to insert.
           * @returns {Function} Fixer function
           * @private
           */
          function createFix(range, text) {
              return function(fixer) {
                  return fixer.replaceTextRange(range, text);
              };
          }
  
          //--------------------------------------------------------------------------
          // Public
          //--------------------------------------------------------------------------
  
          return {
              Program: function checkForlinebreakStyle(node) {
                  const linebreakStyle = context.options[0] || "unix",
                      expectedLF = linebreakStyle === "unix",
                      expectedLFChars = expectedLF ? "
  " : "\r
  ",
                      source = sourceCode.getText(),
                      pattern = astUtils.createGlobalLinebreakMatcher();
                  let match;
  
                  let i = 0;
  
                  while ((match = pattern.exec(source)) !== null) {
                      i++;
                      if (match[0] === expectedLFChars) {
                          continue;
                      }
  
                      const index = match.index;
                      const range = [index, index + match[0].length];
  
                      context.report({
                          node,
                          loc: {
                              line: i,
                              column: sourceCode.lines[i - 1].length
                          },
                          message: expectedLF ? EXPECTED_LF_MSG : EXPECTED_CRLF_MSG,
                          fix: createFix(range, expectedLFChars)
                      });
                  }
              }
          };
      }
  };