'use client';
function wordRegexp(words) {
  return new RegExp("^((" + words.join(")|(") + "))\\b");
}

var singleOperators = new RegExp("^[\\+\\-\\*/&|\\^~<>!@'\\\\]");
var singleDelimiters = new RegExp('^[\\(\\[\\{\\},:=;\\.]');
var doubleOperators = new RegExp("^((==)|(~=)|(<=)|(>=)|(<<)|(>>)|(\\.[\\+\\-\\*/\\^\\\\]))");
var doubleDelimiters = new RegExp("^((!=)|(\\+=)|(\\-=)|(\\*=)|(/=)|(&=)|(\\|=)|(\\^=))");
var tripleDelimiters = new RegExp("^((>>=)|(<<=))");
var expressionEnd = new RegExp("^[\\]\\)]");
var identifiers = new RegExp("^[_A-Za-z\xa1-\uffff][_A-Za-z0-9\xa1-\uffff]*");

var builtins = wordRegexp([
  'error', 'eval', 'function', 'abs', 'acos', 'atan', 'asin', 'cos',
  'cosh', 'exp', 'log', 'prod', 'sum', 'log10', 'max', 'min', 'sign', 'sin', 'sinh',
  'sqrt', 'tan', 'reshape', 'break', 'zeros', 'default', 'margin', 'round', 'ones',
  'rand', 'syn', 'ceil', 'floor', 'size', 'clear', 'zeros', 'eye', 'mean', 'std', 'cov',
  'det', 'eig', 'inv', 'norm', 'rank', 'trace', 'expm', 'logm', 'sqrtm', 'linspace', 'plot',
  'title', 'xlabel', 'ylabel', 'legend', 'text', 'grid', 'meshgrid', 'mesh', 'num2str',
  'fft', 'ifft', 'arrayfun', 'cellfun', 'input', 'fliplr', 'flipud', 'ismember'
]);

var keywords = wordRegexp([
  'return', 'case', 'switch', 'else', 'elseif', 'end', 'endif', 'endfunction',
  'if', 'otherwise', 'do', 'for', 'while', 'try', 'catch', 'classdef', 'properties', 'events',
  'methods', 'global', 'persistent', 'endfor', 'endwhile', 'printf', 'sprintf', 'disp', 'until',
  'continue', 'pkg'
]);


// tokenizers
function tokenTranspose(stream, state) {
  if (!stream.sol() && stream.peek() === '\'') {
    stream.next();
    state.tokenize = tokenBase;
    return 'operator';
  }
  state.tokenize = tokenBase;
  return tokenBase(stream, state);
}


function tokenComment(stream, state) {
  if (stream.match(/^.*%}/)) {
    state.tokenize = tokenBase;
    return 'comment';
  }  stream.skipToEnd();
  return 'comment';
}

function tokenBase(stream, state) {
  // whitespaces
  if (stream.eatSpace()) return null;

  // Handle one line Comments
  if (stream.match('%{')){
    state.tokenize = tokenComment;
    stream.skipToEnd();
    return 'comment';
  }

  if (stream.match(/^[%#]/)){
    stream.skipToEnd();
    return 'comment';
  }

  // Handle Number Literals
  if (stream.match(/^[0-9\.+-]/, false)) {
    if (stream.match(/^[+-]?0x[0-9a-fA-F]+[ij]?/)) {
      stream.tokenize = tokenBase;
      return 'number'; }    if (stream.match(/^[+-]?\d*\.\d+([EeDd][+-]?\d+)?[ij]?/)) { return 'number'; }    if (stream.match(/^[+-]?\d+([EeDd][+-]?\d+)?[ij]?/)) { return 'number'; }  }
  if (stream.match(wordRegexp(['nan','NaN','inf','Inf']))) { return 'number'; }
  // Handle Strings
  var m = stream.match(/^"(?:[^"]|"")*("|$)/) || stream.match(/^'(?:[^']|'')*('|$)/);
  if (m) { return m[1] ? 'string' : "error"; }

  // Handle words
  if (stream.match(keywords)) { return 'keyword'; }  if (stream.match(builtins)) { return 'builtin'; }  if (stream.match(identifiers)) { return 'variable'; }
  if (stream.match(singleOperators) || stream.match(doubleOperators)) { return 'operator'; }  if (stream.match(singleDelimiters) || stream.match(doubleDelimiters) || stream.match(tripleDelimiters)) { return null; }
  if (stream.match(expressionEnd)) {
    state.tokenize = tokenTranspose;
    return null;
  }

  // Handle non-detected items
  stream.next();
  return 'error';
}

const octave = {
  name: "octave",

  startState: function() {
    return {
      tokenize: tokenBase
    };
  },

  token: function(stream, state) {
    var style = state.tokenize(stream, state);
    if (style === 'number' || style === 'variable'){
      state.tokenize = tokenTranspose;
    }
    return style;
  },

  languageData: {
    commentTokens: {line: "%"}
  }
};

export { octave };
