// This file contains code that makes it easy to search handlebar templates for variables.
// Why? To get a clue if you are missing some.

import * as plugins from './smarthbs.plugins';

// the curly regex objects
let tripleCurlyRegex = /{{{\s*[\w\.]+\s*}}}/g;
let doubleCurlyRegex = /{{\s*[\w\.]+\s*}}/g;
let nameInCurlsRegex = /[\w\.]+/;

/**
 * finds all variables in a handlebars template
 * @param hbsStringArg
 */
export let findVarsInHbsString = async (hbsStringArg: string) => {
  let hbsString = hbsStringArg; // make sure we have a new string object that we may destroy
  let varNameArray: string[] = [];
  let tripleCurlyMatches = hbsString.match(tripleCurlyRegex);
  if (tripleCurlyMatches) {
    hbsString = hbsString.replace(tripleCurlyRegex, '[[[replaced]]]');
    varNameArray = plugins.lodash.concat(varNameArray, tripleCurlyMatches);
  }
  let doubleCurlyMatches = hbsString.match(doubleCurlyRegex);
  if (doubleCurlyMatches) {
    varNameArray = plugins.lodash.concat(varNameArray, doubleCurlyMatches);
  }

  // make sure we are clean from curly brackets
  varNameArray = varNameArray.map(x => {
    return x.match(nameInCurlsRegex)[0];
  });

  // make sure are uniq
  varNameArray = plugins.lodash.uniq(varNameArray);
  return varNameArray;
};

/**
 * checks if supplied variables satisfy an handlebars template
 * @param hbsStringArg
 * @param varObjectArg
 * @return string array with missing variable names
 */
export let checkVarsSatisfaction = async (hbsStringArg: string, varObjectArg: any) => {
  // required vars as combined deep string with . notation
  let requiredVarStrings = await findVarsInHbsString(hbsStringArg);

  // comparison objects
  let suppliedVarsObject = varObjectArg;
  let missingVarsObject: string[] = [];

  // building the
  for (let stringVar of requiredVarStrings) {
    let splittedVars = stringVar.split('.');
    let requiredPointer = suppliedVarsObject;
    for (let i = 0; i < splittedVars.length; i++) {
      let splitVar = splittedVars[i];
      let varAvailable = requiredPointer[splitVar] !== undefined;
      if (varAvailable && splittedVars.length === i + 1) {
        // ok
      } else if (varAvailable) {
        requiredPointer = requiredPointer[splitVar];
      } else {
        missingVarsObject.push(stringVar);
        i = splittedVars.length;
      }
    }
  }
  return missingVarsObject;
};