var specialForm = /^(block|let*|return-from|catch|load-time-value|setq|eval-when|locally|symbol-macrolet|flet|macrolet|tagbody|function|multiple-value-call|the|go|multiple-value-prog1|throw|if|progn|unwind-protect|labels|progv|let|quote)$/;
var assumeBody = /^with|^def|^do|^prog|case$|^cond$|bind$|when$|unless$/;
var numLiteral = /^(?:[+\-]?(?:\d+|\d*\.\d+)(?:[efd][+\-]?\d+)?|[+\-]?\d+(?:\/[+\-]?\d+)?|#b[+\-]?[01]+|#o[+\-]?[0-7]+|#x[+\-]?[\da-f]+)/;
var symbol = /[^\s'`,@()\[\]";]/;
var type;

function readSym(stream) {
  var ch;
  while (ch = stream.next()) {
    if (ch == "\\") stream.next();
    else if (!symbol.test(ch)) { stream.backUp(1); break; }
  }
  return stream.current();
}

function base(stream, state) {
  if (stream.eatSpace()) {type = "ws"; return null;}
  if (stream.match(numLiteral)) return "number";
  var ch = stream.next();
  if (ch == "\\") ch = stream.next();

  if (ch == '"') return (state.tokenize = inString)(stream, state);
  else if (ch == "(") { type = "open"; return "bracket"; }
  else if (ch == ")" || ch == "]") { type = "close"; return "bracket"; }
  else if (ch == ";") { stream.skipToEnd(); type = "ws"; return "comment"; }
  else if (/['`,@]/.test(ch)) return null;
  else if (ch == "|") {
    if (stream.skipTo("|")) { stream.next(); return "variableName"; }
    else { stream.skipToEnd(); return "error"; }
  } else if (ch == "#") {
    var ch = stream.next();
    if (ch == "(") { type = "open"; return "bracket"; }
    else if (/[+\-=\.']/.test(ch)) return null;
    else if (/\d/.test(ch) && stream.match(/^\d*#/)) return null;
    else if (ch == "|") return (state.tokenize = inComment)(stream, state);
    else if (ch == ":") { readSym(stream); return "meta"; }
    else if (ch == "\\") { stream.next(); readSym(stream); return "string.special" }
    else return "error";
  } else {
    var name = readSym(stream);
    if (name == ".") return null;
    type = "symbol";
    if (name == "nil" || name == "t" || name.charAt(0) == ":") return "atom";
    if (state.lastType == "open" && (specialForm.test(name) || assumeBody.test(name))) return "keyword";
    if (name.charAt(0) == "&") return "variableName.special";
    return "variableName";
  }
}

function inString(stream, state) {
  var escaped = false, next;
  while (next = stream.next()) {
    if (next == '"' && !escaped) { state.tokenize = base; break; }
    escaped = !escaped && next == "\\";
  }
  return "string";
}

function inComment(stream, state) {
  var next, last;
  while (next = stream.next()) {
    if (next == "#" && last == "|") { state.tokenize = base; break; }
    last = next;
  }
  type = "ws";
  return "comment";
}

const commonLisp = {
  startState: function () {
    return {ctx: {prev: null, start: 0, indentTo: 0}, lastType: null, tokenize: base};
  },

  token: function (stream, state) {
    if (stream.sol() && typeof state.ctx.indentTo != "number")
      state.ctx.indentTo = state.ctx.start + 1;

    type = null;
    var style = state.tokenize(stream, state);
    if (type != "ws") {
      if (state.ctx.indentTo == null) {
        if (type == "symbol" && assumeBody.test(stream.current()))
          state.ctx.indentTo = state.ctx.start + stream.indentUnit;
        else
          state.ctx.indentTo = "next";
      } else if (state.ctx.indentTo == "next") {
        state.ctx.indentTo = stream.column();
      }
      state.lastType = type;
    }
    if (type == "open") state.ctx = {prev: state.ctx, start: stream.column(), indentTo: null};
    else if (type == "close") state.ctx = state.ctx.prev || state.ctx;
    return style;
  },

  indent: function (state) {
    var i = state.ctx.indentTo;
    return typeof i == "number" ? i : state.ctx.start + 1;
  },

  languageData: {
    commentTokens: {line: ";;", block: {open: "#|", close: "|#"}},
    closeBrackets: {brackets: ["(", "[", "{", '"']}
  }
};

export { commonLisp };
