/*
 *
 * Diff Parser (diff-parser.js)
 * Author: rtfpessoa
 *
 */

var utils = new Utils();

var LINE_TYPE = {
  INSERTS: "d2h-ins",
  DELETES: "d2h-del",
  CONTEXT: "d2h-cntx",
  INFO: "d2h-info"
};

function DiffParser() {
}

DiffParser.prototype.LINE_TYPE = LINE_TYPE;

DiffParser.prototype.generateDiffJson = function (diffInput) {
  var files = [],
    currentFile = null,
    currentBlock = null,
    oldLine = null,
    newLine = null;

  var saveBlock = function () {
    /* add previous block(if exists) before start a new file */
    if (currentBlock) {
      currentFile.blocks.push(currentBlock);
      currentBlock = null;
    }
  };

  var saveFile = function () {
    /*
     * add previous file(if exists) before start a new one
     * if it has name (to avoid binary files errors)
     */
    if (currentFile && currentFile.newName) {
      files.push(currentFile);
      currentFile = null;
    }
  };

  var startFile = function () {
    saveBlock();
    saveFile();

    /* create file structure */
    currentFile = {};
    currentFile.blocks = [];
    currentFile.deletedLines = 0;
    currentFile.addedLines = 0;
  };

  var startBlock = function (line) {
    saveBlock();

    var values;

    if (values = /^@@ -(\d+),\d+ \+(\d+),\d+ @@.*/.exec(line)) {
      currentFile.isTripleDiff = false;
    } else if (values = /^@@@ -(\d+),\d+ -\d+,\d+ \+(\d+),\d+ @@@.*/.exec(line)) {
      currentFile.isTripleDiff = true;
    } else {
      values = [0, 0];
      currentFile.isTripleDiff = false;
    }

    oldLine = values[1];
    newLine = values[2];

    /* create block metadata */
    currentBlock = {};
    currentBlock.lines = [];
    currentBlock.oldStartLine = oldLine;
    currentBlock.newStartLine = newLine;
    currentBlock.header = line;
  };

  var createLine = function (line) {
    var currentLine = {};
    currentLine.content = line;

    /* fill the line data */
    if (utils.startsWith(line, "+") || utils.startsWith(line, " +")) {
      currentFile.addedLines++;

      currentLine.type = LINE_TYPE.INSERTS;
      currentLine.oldNumber = null;
      currentLine.newNumber = newLine++;

      currentBlock.lines.push(currentLine);

    } else if (utils.startsWith(line, "-") || utils.startsWith(line, " -")) {
      currentFile.deletedLines++;

      currentLine.type = LINE_TYPE.DELETES;
      currentLine.oldNumber = oldLine++;
      currentLine.newNumber = null;

      currentBlock.lines.push(currentLine);

    } else {
      currentLine.type = LINE_TYPE.CONTEXT;
      currentLine.oldNumber = oldLine++;
      currentLine.newNumber = newLine++;

      currentBlock.lines.push(currentLine);
    }
  };

  var diffLines = diffInput.split("\n");
  diffLines.forEach(function (line) {
    // Unmerged paths, and possibly other non-diffable files
    // https://github.com/scottgonzalez/pretty-diff/issues/11
    // Also, remove some useless lines
    if (!line || utils.startsWith(line, "*") ||
      utils.startsWith(line, "new") || utils.startsWith(line, "index")) {
      return;
    }

    var values = [];
    if (utils.startsWith(line, "diff")) {
      startFile();
    } else if (currentFile && !currentFile.oldName && (values = /^--- a\/(\S+).*$/.exec(line))) {
      currentFile.oldName = values[1];
    } else if (currentFile && !currentFile.newName && (values = /^\+\+\+ [b]?\/(\S+).*$/.exec(line))) {
      currentFile.newName = values[1];

      var fileSplit = currentFile.newName.split(".");
      currentFile.language = fileSplit[fileSplit.length - 1];
    } else if (currentFile && utils.startsWith(line, "@@")) {
      startBlock(line);
    } else if (currentBlock) {
      createLine(line);
    }
  });

  saveBlock();
  saveFile();

  return files;
};