// final draft
$(document).ready(function() {

    var entry = '';
    var ans = '';
    var current = '';
    var log = '';
    var decimal = true;
    var reset = '';
  
    // round function if answer includes a decimal
    function round(val) {
      val = val.toString().split('');
      if (val.indexOf('.') !== -1) {
        var valTest = val.slice(val.indexOf('.') + 1, val.length);
        val = val.slice(0, val.indexOf('.') + 1);
        var i = 0;
        while (valTest[i] < 1) {
          i++
        }
        valTest = valTest.join('').slice(0, i + 2);
        if (valTest[valTest.length-1] === '0') {
          valTest = valTest.slice(0, -1);
        }
        return val.join('') + valTest;
      } else {
        return val.join('');
      }
    }
  
    $('button').click(function() {
  
      entry = $(this).attr("value");
      console.log('entry: ' + entry);
  
      //reset for log after answer to equation.
      if (reset) {
        if (entry === '/' || entry === '*' || entry === '-' || entry === '+') {
          log = ans;
        } else {
          ans = '';
        }
      }
      reset = false;
  
      // All clear or Clear Entry
      if (entry === 'ac' || entry === 'ce' && current === 'noChange') {
        ans = '';
        current = '';
        entry = '';
        log = '';
        $('#history').html('0');
        $('#answer').html('0');
        decimal = true;
      } else if (entry === 'ce') {
        $('#history').html(log.slice(0, -current.length));
        log = log.slice(0, -current.length);
        ans = ans.slice(0, -current.length);
        current = ans;
        if (log.length === 0 || log === ' ') {
          $('#history').html('0');
        }
        $('#answer').html('0');
        entry = '';
        decimal = true;
      }
  
      // prevents more than one deciminal in a number
      if (entry === '.' || entry === '0.') {
        if (!decimal) {
          entry = '';
        }
      }
  
      // prevents improper use of first digit
      if (ans.length === 0 && isNaN(entry) && entry !== '.' || ans.length === 0 && entry === '0') {
        entry = '';
        ans = '';
      }
  
      // prevents extra operators
      if (current !== 'noChange') {
        if (current === '' && isNaN(entry) && entry !== '.' || isNaN(current) && isNaN(entry) && entry !== '.') {
          entry = '';
        }
      }
  
      // digit combining
      while (Number(entry) || entry === '0' || current === '.') {
  
        if (isNaN(current) && entry === '0' && current !== '.') {
          entry = '';
        } else if (isNaN(current) && Number(entry) && current !== '.') {
          current = '';
        }
        if (entry === '.') {
          decimal = false;
        }
        if (current === '0.' && isNaN(entry)) {
          entry = '';
        } else {
          if (current[current.length - 1] === '.') {
            current = current.concat(entry);
          } else {
            current += entry;
          }
          ans += entry;
          $('#answer').html(current);
          log += entry;
          $('#history').html(log);
          entry = '';
        }
      }
  
      // Operation list
  
      if (entry === '.') {
        if (current === '' || isNaN(current[current.length - 1])) {
          current = '0.';
          ans += entry;
          $('#answer').html('0.');
          log += current;
          $('#history').html(log);
  
        } else {
          current = current.concat('.');
          ans = ans.concat('.');
          log = ans;
          $('#history').html(ans);
          $('#answer').html(current);
        }
        entry = '';
        decimal = false;
  
      } else if (entry === '/') {
        current = '/';
        ans = round(eval(ans)) + current;
        log += current;
        $('#history').html(log);
        $('#answer').html('/');
        entry = '';
        decimal = true;
  
      } else if (entry === '*') {
        current = '*';
        ans = round(eval(ans)) + current;
        log += 'x';
        $('#history').html(log);
        $('#answer').html('x');
        entry = '';
        decimal = true;
  
      } else if (entry === '-') {
        current = '-';
        ans = round(eval(ans)) + current;
        log += current;
        $('#history').html(log);
        $('#answer').html('-');
        entry = '';
        decimal = true;
  
      } else if (entry === '+') {
        current = '+';
        ans = round(eval(ans)) + current;
        log += current;
        $('#history').html(log);
        $('#answer').html('+');
        entry = '';
        decimal = true;
  
      } else if (entry === '=') {
        if (current[current.length - 1] === '.') {
          entry = '';
        } else {
          current = eval(ans).toString();
          $('#answer').html(round(eval(ans)));
          ans = round(eval(ans));
          log += entry + ans;
          $('#history').html(log);
          log = ans;
          entry = '';
          reset = true;
          decimal = true;
        }
        current = 'noChange';
      }
      entry = '';
  
      if (reset) {
        log = '';
      }
  
      // max digits on screen
      if ($('#entry').children().text().length > 8 || $('#history').text().length > 22) {
        $('#answer').html('0');
        $('#history').html('Digit Limit Met');
        current = '';
        ans = '';
        log = '';
        decimal = true;
      }
  
      console.log('decimal: ' + decimal);
      console.log('current: ' + current);
      console.log('answer: ' + ans);
      console.log($('#history').text().length);
    });
  }); // end doc ready function