"use strict";

var [BRA, KET, IDENT] = ['BRA', 'KET', 'IDENT'];

function last(arr){ return arr[arr.length -1] };

export default function act(src, prefix){
  var tree = src.split('').reduce((tokens, char)=> {
    if(char==='{'){
      tokens.push({type: BRA});
    }
    if(char==='}'){
      tokens.push({type: KET});
    }
    if(/\s/.test(char)){
      if(tokens.identBuffer){
        tokens.push({type: IDENT, val: tokens.identBuffer.join('')});
        tokens.identBuffer= null;
      }
    }
    if(/[a-z0-9]/i.test(char)){
      tokens.identBuffer = tokens.identBuffer || [];
      tokens.identBuffer.push(char);
    }

    return tokens;
  }, [])
  .reduce((stack, token) => {
    switch(token.type){
      case BRA: 
        stack.push([]); 
        break;
      case KET: 
        if (stack.length===1) break; 
        let children = stack.pop(); 
        last(last(stack)).children = children; 
        break;
      case IDENT: 
        last(stack).push(token);
        break;
      default: break;
    }
    return stack;
  }, [])[0];

  return toObj(tree);

  function toObj(arr, path=[]) {
    return arr.reduce((o, node)=>
      Object.assign(o, {
        [node.val] : Object.assign(
          {toString: () => (prefix?[prefix]:[]).concat(path).concat(node.val).join(':')}, 
          node.children ? toObj(node.children, path.concat(node.val)) : {})}), {});
  }
}