/**
 * Author: Gautam Mehta
 * Branched from CodeMirror's Scheme mode
 */
CodeMirror.defineMode("cobol", function () {
  var BUILTIN = "builtin", COMMENT = "comment", STRING = "string",
      ATOM = "atom", NUMBER = "number", KEYWORD = "keyword", MODTAG = "header",
      COBOLLINENUM = "def", PERIOD = "link";
  function makeKeywords(str) {
    var obj = {}, words = str.split(" ");
    for (var i = 0; i < words.length; ++i) obj[words[i]] = true;
    return obj;
  }
  var atoms = makeKeywords("TRUE FALSE ZEROES ZEROS ZERO SPACES SPACE LOW-VALUE LOW-VALUES ");
  var keywords = makeKeywords(
      "ACCEPT ACCESS ACQUIRE ADD ADDRESS " +
      "ADVANCING AFTER ALIAS ALL ALPHABET " +
      "ALPHABETIC ALPHABETIC-LOWER ALPHABETIC-UPPER ALPHANUMERIC ALPHANUMERIC-EDITED " +
      "ALSO ALTER ALTERNATE AND ANY " +
      "ARE AREA AREAS ARITHMETIC ASCENDING " +
      "ASSIGN AT ATTRIBUTE AUTHOR AUTO " +
      "AUTO-SKIP AUTOMATIC B-AND B-EXOR B-LESS " +
      "B-NOT B-OR BACKGROUND-COLOR BACKGROUND-COLOUR BEEP " +
      "BEFORE BELL BINARY BIT BITS " +
      "BLANK BLINK BLOCK BOOLEAN BOTTOM " +
      "BY CALL CANCEL CD CF " +
      "CH CHARACTER CHARACTERS CLASS CLOCK-UNITS " +
      "CLOSE COBOL CODE CODE-SET COL " +
      "COLLATING COLUMN COMMA COMMIT COMMITMENT " +
      "COMMON COMMUNICATION COMP COMP-0 COMP-1 " +
      "COMP-2 COMP-3 COMP-4 COMP-5 COMP-6 " +
      "COMP-7 COMP-8 COMP-9 COMPUTATIONAL COMPUTATIONAL-0 " +
      "COMPUTATIONAL-1 COMPUTATIONAL-2 COMPUTATIONAL-3 COMPUTATIONAL-4 COMPUTATIONAL-5 " +
      "COMPUTATIONAL-6 COMPUTATIONAL-7 COMPUTATIONAL-8 COMPUTATIONAL-9 COMPUTE " +
      "CONFIGURATION CONNECT CONSOLE CONTAINED CONTAINS " +
      "CONTENT CONTINUE CONTROL CONTROL-AREA CONTROLS " +
      "CONVERTING COPY CORR CORRESPONDING COUNT " +
      "CRT CRT-UNDER CURRENCY CURRENT CURSOR " +
      "DATA DATE DATE-COMPILED DATE-WRITTEN DAY " +
      "DAY-OF-WEEK DB DB-ACCESS-CONTROL-KEY DB-DATA-NAME DB-EXCEPTION " +
      "DB-FORMAT-NAME DB-RECORD-NAME DB-SET-NAME DB-STATUS DBCS " +
      "DBCS-EDITED DE DEBUG-CONTENTS DEBUG-ITEM DEBUG-LINE " +
      "DEBUG-NAME DEBUG-SUB-1 DEBUG-SUB-2 DEBUG-SUB-3 DEBUGGING " +
      "DECIMAL-POINT DECLARATIVES DEFAULT DELETE DELIMITED " +
      "DELIMITER DEPENDING DESCENDING DESCRIBED DESTINATION " +
      "DETAIL DISABLE DISCONNECT DISPLAY DISPLAY-1 " +
      "DISPLAY-2 DISPLAY-3 DISPLAY-4 DISPLAY-5 DISPLAY-6 " +
      "DISPLAY-7 DISPLAY-8 DISPLAY-9 DIVIDE DIVISION " +
      "DOWN DROP DUPLICATE DUPLICATES DYNAMIC " +
      "EBCDIC EGI EJECT ELSE EMI " +
      "EMPTY EMPTY-CHECK ENABLE END END. END-ACCEPT END-ACCEPT. " +
      "END-ADD END-CALL END-COMPUTE END-DELETE END-DISPLAY " +
      "END-DIVIDE END-EVALUATE END-IF END-INVOKE END-MULTIPLY " +
      "END-OF-PAGE END-PERFORM END-READ END-RECEIVE END-RETURN " +
      "END-REWRITE END-SEARCH END-START END-STRING END-SUBTRACT " +
      "END-UNSTRING END-WRITE END-XML ENTER ENTRY " +
      "ENVIRONMENT EOP EQUAL EQUALS ERASE " +
      "ERROR ESI EVALUATE EVERY EXCEEDS " +
      "EXCEPTION EXCLUSIVE EXIT EXTEND EXTERNAL " +
      "EXTERNALLY-DESCRIBED-KEY FD FETCH FILE FILE-CONTROL " +
      "FILE-STREAM FILES FILLER FINAL FIND " +
      "FINISH FIRST FOOTING FOR FOREGROUND-COLOR " +
      "FOREGROUND-COLOUR FORMAT FREE FROM FULL " +
      "FUNCTION GENERATE GET GIVING GLOBAL " +
      "GO GOBACK GREATER GROUP HEADING " +
      "HIGH-VALUE HIGH-VALUES HIGHLIGHT I-O I-O-CONTROL " +
      "ID IDENTIFICATION IF IN INDEX " +
      "INDEX-1 INDEX-2 INDEX-3 INDEX-4 INDEX-5 " +
      "INDEX-6 INDEX-7 INDEX-8 INDEX-9 INDEXED " +
      "INDIC INDICATE INDICATOR INDICATORS INITIAL " +
      "INITIALIZE INITIATE INPUT INPUT-OUTPUT INSPECT " +
      "INSTALLATION INTO INVALID INVOKE IS " +
      "JUST JUSTIFIED KANJI KEEP KEY " +
      "LABEL LAST LD LEADING LEFT " +
      "LEFT-JUSTIFY LENGTH LENGTH-CHECK LESS LIBRARY " +
      "LIKE LIMIT LIMITS LINAGE LINAGE-COUNTER " +
      "LINE LINE-COUNTER LINES LINKAGE LOCAL-STORAGE " +
      "LOCALE LOCALLY LOCK " +
      "MEMBER MEMORY MERGE MESSAGE METACLASS " +
      "MODE MODIFIED MODIFY MODULES MOVE " +
      "MULTIPLE MULTIPLY NATIONAL NATIVE NEGATIVE " +
      "NEXT NO NO-ECHO NONE NOT " +
      "NULL NULL-KEY-MAP NULL-MAP NULLS NUMBER " +
      "NUMERIC NUMERIC-EDITED OBJECT OBJECT-COMPUTER OCCURS " +
      "OF OFF OMITTED ON ONLY " +
      "OPEN OPTIONAL OR ORDER ORGANIZATION " +
      "OTHER OUTPUT OVERFLOW OWNER PACKED-DECIMAL " +
      "PADDING PAGE PAGE-COUNTER PARSE PERFORM " +
      "PF PH PIC PICTURE PLUS " +
      "POINTER POSITION POSITIVE PREFIX PRESENT " +
      "PRINTING PRIOR PROCEDURE PROCEDURE-POINTER PROCEDURES " +
      "PROCEED PROCESS PROCESSING PROGRAM PROGRAM-ID " +
      "PROMPT PROTECTED PURGE QUEUE QUOTE " +
      "QUOTES RANDOM RD READ READY " +
      "REALM RECEIVE RECONNECT RECORD RECORD-NAME " +
      "RECORDS RECURSIVE REDEFINES REEL REFERENCE " +
      "REFERENCE-MONITOR REFERENCES RELATION RELATIVE RELEASE " +
      "REMAINDER REMOVAL RENAMES REPEATED REPLACE " +
      "REPLACING REPORT REPORTING REPORTS REPOSITORY " +
      "REQUIRED RERUN RESERVE RESET RETAINING " +
      "RETRIEVAL RETURN RETURN-CODE RETURNING REVERSE-VIDEO " +
      "REVERSED REWIND REWRITE RF RH " +
      "RIGHT RIGHT-JUSTIFY ROLLBACK ROLLING ROUNDED " +
      "RUN SAME SCREEN SD SEARCH " +
      "SECTION SECURE SECURITY SEGMENT SEGMENT-LIMIT " +
      "SELECT SEND SENTENCE SEPARATE SEQUENCE " +
      "SEQUENTIAL SET SHARED SIGN SIZE " +
      "SKIP1 SKIP2 SKIP3 SORT SORT-MERGE " +
      "SORT-RETURN SOURCE SOURCE-COMPUTER SPACE-FILL " +
      "SPECIAL-NAMES STANDARD STANDARD-1 STANDARD-2 " +
      "START STARTING STATUS STOP STORE " +
      "STRING SUB-QUEUE-1 SUB-QUEUE-2 SUB-QUEUE-3 SUB-SCHEMA " +
      "SUBFILE SUBSTITUTE SUBTRACT SUM SUPPRESS " +
      "SYMBOLIC SYNC SYNCHRONIZED SYSIN SYSOUT " +
      "TABLE TALLYING TAPE TENANT TERMINAL " +
      "TERMINATE TEST TEXT THAN THEN " +
      "THROUGH THRU TIME TIMES TITLE " +
      "TO TOP TRAILING TRAILING-SIGN TRANSACTION " +
      "TYPE TYPEDEF UNDERLINE UNEQUAL UNIT " +
      "UNSTRING UNTIL UP UPDATE UPON " +
      "USAGE USAGE-MODE USE USING VALID " +
      "VALIDATE VALUE VALUES VARYING VLR " +
      "WAIT WHEN WHEN-COMPILED WITH WITHIN " +
      "WORDS WORKING-STORAGE WRITE XML XML-CODE " +
      "XML-EVENT XML-NTEXT XML-TEXT ZERO ZERO-FILL " );

  var builtins = makeKeywords("- * ** / + < <= = > >= ");
  var tests = {
    digit: /\d/,
    digit_or_colon: /[\d:]/,
    hex: /[0-9a-f]/i,
    sign: /[+-]/,
    exponent: /e/i,
    keyword_char: /[^\s\(\[\;\)\]]/,
    symbol: /[\w*+\-]/
  };
  function isNumber(ch, stream){
    // hex
    if ( ch === '0' && stream.eat(/x/i) ) {
      stream.eatWhile(tests.hex);
      return true;
    }
    // leading sign
    if ( ( ch == '+' || ch == '-' ) && ( tests.digit.test(stream.peek()) ) ) {
      stream.eat(tests.sign);
      ch = stream.next();
    }
    if ( tests.digit.test(ch) ) {
      stream.eat(ch);
      stream.eatWhile(tests.digit);
      if ( '.' == stream.peek()) {
        stream.eat('.');
        stream.eatWhile(tests.digit);
      }
      if ( stream.eat(tests.exponent) ) {
        stream.eat(tests.sign);
        stream.eatWhile(tests.digit);
      }
      return true;
    }
    return false;
  }
  return {
    startState: function () {
      return {
        indentStack: null,
        indentation: 0,
        mode: false
      };
    },
    token: function (stream, state) {
      if (state.indentStack == null && stream.sol()) {
        // update indentation, but only if indentStack is empty
        state.indentation = 6 ; //stream.indentation();
      }
      // skip spaces
      if (stream.eatSpace()) {
        return null;
      }
      var returnType = null;
      switch(state.mode){
      case "string": // multi-line string parsing mode
        var next = false;
        while ((next = stream.next()) != null) {
          if (next == "\"" || next == "\'") {
            state.mode = false;
            break;
          }
        }
        returnType = STRING; // continue on in string mode
        break;
      default: // default parsing mode
        var ch = stream.next();
        var col = stream.column();
        if (col >= 0 && col <= 5) {
          returnType = COBOLLINENUM;
        } else if (col >= 72 && col <= 79) {
          stream.skipToEnd();
          returnType = MODTAG;
        } else if (ch == "*" && col == 6) { // comment
          stream.skipToEnd(); // rest of the line is a comment
          returnType = COMMENT;
        } else if (ch == "\"" || ch == "\'") {
          state.mode = "string";
          returnType = STRING;
        } else if (ch == "'" && !( tests.digit_or_colon.test(stream.peek()) )) {
          returnType = ATOM;
        } else if (ch == ".") {
          returnType = PERIOD;
        } else if (isNumber(ch,stream)){
          returnType = NUMBER;
        } else {
          if (stream.current().match(tests.symbol)) {
            while (col < 71) {
              if (stream.eat(tests.symbol) === undefined) {
                break;
              } else {
                col++;
              }
            }
          }
          if (keywords && keywords.propertyIsEnumerable(stream.current().toUpperCase())) {
            returnType = KEYWORD;
          } else if (builtins && builtins.propertyIsEnumerable(stream.current().toUpperCase())) {
            returnType = BUILTIN;
          } else if (atoms && atoms.propertyIsEnumerable(stream.current().toUpperCase())) {
            returnType = ATOM;
          } else returnType = null;
        }
      }
      return returnType;
    },
    indent: function (state) {
      if (state.indentStack == null) return state.indentation;
      return state.indentStack.indent;
    }
  };
});

CodeMirror.defineMIME("text/x-cobol", "cobol");
