//repaint page based on user choice from dropdown selector 
function dropdownChoice() {
  "use strict";
  document.getElementById("textbox").value = "";
  document.getElementById("number").value = "";
  document.getElementById("output-area").innerHTML = "";
  document.getElementById("number").style.visibility = "hidden";
  var script = document.getElementById("dropdown").value;

  switch (script) {
    case "cToF":
      document.getElementById("descTitle").innerHTML = "Convert Celsius to Fahrenheit";
      document.getElementById("descText").innerHTML = "The formula to convert from Celsius to Fahrenheit is; <code>F = (C x (9/5)) + 32</code>";
      document.getElementById("descTests").innerHTML = "<li><var>-30</var> should return a value of <var>-22</var></li><li><var>-10</var> should return a value of <var>14</var></li><li><var>0</var> should return a value of <var>32</var></li><li><var>20</var> should return a value of <var>68</var></li><li><var>30</var> should return a value of <var>86</var></li>";
      document.getElementById("textbox").placeholder = "-40";
      break;
      
    case "fToC":
      document.getElementById("descTitle").innerHTML = "Convert Fahrenheit to Celsius";
      document.getElementById("descText").innerHTML = "The formula to convert from Fahrenheit to Celsius is; <code>C = (F-32) * (5/9)</code><br> This wasn't a script in the course but being in the U.S. I have more reason to use this conversion.<br> One day I'll write a toggle so you don't have to choose from the dropdown.";
      document.getElementById("descTests").innerHTML = "<li><i>-40</i> should return a value of <i>-40</i> (it's where the two scales cross)</li><li><i>32</i> should return a value of <i>0</i></li><li><i>68</i> should return a value of <i>20</i></li><li><i>212</i> (boiling point of water) should return a value of <i>100</i></li><li><i>451</i> (ignition temp of paper) should return a value of <i></i>233</li>";
      document.getElementById("textbox").placeholder = "72";
      break;

    case "revString":
      document.getElementById("descTitle").innerHTML = "Reverse a String";
      document.getElementById("descText").innerHTML = "Reverse the provided string";
      document.getElementById("descTests").innerHTML = "<li>\"hello\" should become \"olleh\"</li><li>\"Howdy\" should become \"ydwoH\"</li><li>\"Greetings from Earth\" should become \"htraE morf sgniteerG\"</li>";
      document.getElementById("textbox").placeholder = "stressed";
      break;

    case "factorial":
      document.getElementById("descTitle").innerHTML = "Factorialize a Number";
      document.getElementById("descText").innerHTML = "Return the factorial of the provided integer. If the integer is represented with the letter n, a factorial is the product of all positive integers less than or equal to n. Factorials are often represented with the shorthand notation n!<br> For example: 5! = 1 x 2 x 3 x 4 x 5 = 120<br> Only integers greater than or equal to zero will be supplied to the function.";
      document.getElementById("descTests").innerHTML = "<li><var>5</var> should return <var>120</var><li><var>10</var> should return <var>3628800</var><li><var>20</var> should return <var>2432902008176640000</var><li><var>0</var> should return <var>1</var>";
      document.getElementById("textbox").placeholder = "11";
      break;

    case "longest":
      document.getElementById("descTitle").innerHTML = "Find the Longest Word in a String";
      document.getElementById("descText").innerHTML = "Return the length of the longest word in the provided sentence.<br> The response should be a number";
      document.getElementById("descTests").innerHTML = "<li>\"The quick brown fox jumped over the lazy sleeping dog\" should return 8</li><li>\"May the force be with you\" should return 5</li><li>\"Google do a barrel roll\" should return 6</li><li>\"What is the average airspeed velocity of an unladen swallow\" should return 8</li><li>\"What if we try a super-long word such as otorhinolaryngology\" should return 19</li>";
      document.getElementById("textbox").placeholder = "May the Fourth is Star Wars day";
      break;

    case "ending":
      document.getElementById("descTitle").innerHTML = "Confirm the Ending";
      document.getElementById("descText").innerHTML = "- Check if a string (first argument, <code>str</code>) ends with the given target string (second argument, <code>target</code>).<br> - This challenge <em>can</em> be solved with the <code>.endsWith()</code> method, which was introduced in ES2015. But for the purpose of this challenge, we would like you to use one of the JavaScript substring methods instead.";
      document.getElementById("descTests").innerHTML = "<li>\"Bastian\", \"n\" should return true</li><li>\"Congratulation\", \"on\" should return true</li><li>\"Connor\", \"n\" should return false</li><li>\"Walking on water and developing software from a specification are easy if both are frozen\", \"specification\" should return false</li><li>\"He has to give me a new name\", \"name\" should return true</li><li>\"Open sesame\", \"same\" should return true</li><li>\"Open sesame\", \"pen\" should return false</li><li>\"Open sesame\", \"game\" should return false</li><li>\"If you want to save our world, you must hurry. We dont know how much longer we can withstand the nothing\", \"mountain\" should return false</li><li>\"Abstraction\", \"action\" should return true</li>";
      document.getElementById("textbox").placeholder = "bicycle";
      document.getElementById("number").style.visibility = "visible";
      document.getElementById("number").placeholder = "cycle";
      break;

    case "repeat":
      document.getElementById("descTitle").innerHTML = "Repeat a String Repeat a String";
      document.getElementById("descText").innerHTML = "Repeat a given string <code>str</code> (first argument) for <code>num</code> times (second argument). Return an empty string if <code>num</code> is not a positive number.<br> The built-in <code>repeat()</code> method should not be used";
      document.getElementById("descTests").innerHTML = "<li>\"*\", 3 should return \"***\"</li><li>\"abc\", 3 should return \"abcabcabc\"</li><li>\"abc\", 4 should return \"abcabcabcabc\"</li><li>\"abc\", 1 should return \"abc\"</li><li>\"*\", 8 should return \"********\"</li><li>\"abc\", -2 should return \" \"</li>";
      document.getElementById("textbox").placeholder = "tick-tock";
      document.getElementById("number").style.visibility = "visible";
      document.getElementById("number").placeholder = "2";
      break;

    case "truncate":
      document.getElementById("descTitle").innerHTML = "Truncate a String";
      document.getElementById("descText").innerHTML = "Truncate a string (first argument) if it is longer than the given maximum string length (second argument). Return the truncated string with a <code>...</code> ending.";
      document.getElementById("descTests").innerHTML = "<li>\"A-tisket a-tasket A green and yellow basket\", 8 should return \"A-tisket...\"</li><li>\"Peter Piper picked a peck of pickled peppers\", 11 should return \"Peter Piper...\"</li><li><s>\"A-tisket a-tasket A green and yellow basket\", \"A-tisket a-tasket A green and yellow basket\".length should return \"A-tisket a-tasket A green and yellow basket\"</s> Don't have a way to test this...yet</li><li><s>\"A-tisket a-tasket A green and yellow basket\", \"A-tisket a-tasket A green and yellow basket\".length + 2 should return \"A-tisket a-tasket A green and yellow basket\"</s> Don't have a way to test this...yet</li><li>\"A-\", 1 should return \"A...\"</li><li>\"Absolutely Longer\", 2 should return \"Ab...\"</li>";
      document.getElementById("textbox").placeholder = "GitHub cheat sheet";
      document.getElementById("number").style.visibility = "visible";
      document.getElementById("number").placeholder = "6";
      break;

    case "titleCase":
      document.getElementById("descTitle").innerHTML = "Title Case a Sentence";
      document.getElementById("descText").innerHTML = "Return the provided string with the first letter of each word capitalized. Make sure the rest of the word is in lower case.<br> For the purpose of this exercise, you should also capitalize connecting words like 'the' and 'of'.";
      document.getElementById("descTests").innerHTML = "<li>\"I'm a little tea pot\" should return a string</li><li>\"I'm a little tea pot\" should return \"I'm A Little Tea Pot\"</li><li>\"sHoRt AnD sToUt\" should return \"Short And Stout\"</li><li>\"HERE IS MY HANDLE HERE IS MY SPOUT\" should return \"Here Is My Handle Here Is My Spout\"</li>";
      document.getElementById("textbox").placeholder = "wHo TyPeS LiKe ThIs?";
      break;
    
    default:
      //do nothing;
  }
}
//end page setup


//Basic Algorithm Scripts

//convert celsius to fahrenheit
function convertToF(celsius) {
  var fahrenheit;
  const tempFahrenheit = (celsius * (9 / 5) + 32);
  fahrenheit = tempFahrenheit.toFixed(1);
  return fahrenheit;
}

//convert from fahrenheit to celsius
function convertToC(fahrenheit) {
  var celsius;
  const tempCelsius = ((fahrenheit - 32) * (5/9));
  celsius = tempCelsius.toFixed(1);
  return celsius;
}

//reverse a string
function reverseString(str) {
  var splitString = str.split("");
  var reverseArray = splitString.reverse();
  var joinArray = reverseArray.join("");
  return joinArray;
}

//factorialize a positive integer
function factorialize(num) {
  var answer = 0;
  if (num == 0) {
    answer = 1;
  } else {
    answer = num * factorialize(num - 1);
  }
  return answer;
}

//find the longest word in a string
function findLongestWordLength(str) {
  var eachWord = str.split(" ");
  var longestWord = 0;
  //  console.log("Split words are ",eachWord);
  for (var i = 0; i < eachWord.length; i++) {
    if (eachWord[i].length > longestWord) {
      longestWord = eachWord[i].length;
    }
  }
  return longestWord;
}

//confirm the ending is the same
function confirmEnding(str, target) {
  var doesIt = "";
  doesIt = str.indexOf(target, str.length - target.length) !== -1;
  return doesIt;
}

//repeat a string n number of times
function repeatStringNumTimes(str, num) {
  if (num <= 0) {
    return "";
  } else if (num === 1) {
    return str;
  } else {
    str = str + repeatStringNumTimes(str, num - 1);
  }
  return str;
}

//truncate a string
function truncateString(str, num) {
  if (str.length > num) {
    return str.substring(0, num) + '...';
  } else {
    return str;
  }
}

//uppercase the first letter of each word in a sentence, all other letters lowercase
function titleCase(str) {
  let words = str.toLowerCase().split(' ');
  let capitalWords = [];
  for (let i = 0; i < words.length; i++) {
    capitalWords.push(words[i].charAt(0).toUpperCase() + words[i].slice(1));
  }
  return capitalWords.join(' ');
}

//End scripts

//populate the output area
function userInput(script, str) {
  "use strict";
  script = document.getElementById("dropdown").value;
  let userInput = document.getElementById("textbox").value;
  let userInput2 = document.getElementById("number").value;
  var output = '';

  switch (script) {
    case ("cToF"):
      var faren = convertToF(userInput);
      output = `${userInput} °C equals ${faren} °F`;
      console.log('output=', output);
      break;
      
    case ("fToC"):
      var celsius = convertToC(userInput);
      output = `${userInput} °F equals ${celsius} °C`;
      console.log('output=', output);
      break;

    case ("revString"):
      output = reverseString(userInput);
      console.log('output=', output);
      break;

    case ("factorial"):
      if (userInput <0) {
        output = "Input must be 0 or greater";
      } else {
        var factorialNum = factorialize(userInput);
        output = `${userInput}! = ${factorialNum}`;
        console.log('output=', output);
      }
      break;

    case ("longest"):
      var longestLength = findLongestWordLength(userInput);
      output = `The longest word is ${longestLength} characters`;
      console.log('output=', output);
      break;

    case ("ending"):
      output = confirmEnding(userInput, userInput2);
      console.log('output=', output);
      break;

    case ("repeat"):
      if (isNaN(userInput2)) {
        output = "The second argument must be an integer";
      } else {
        output = repeatStringNumTimes(userInput, userInput2);
        console.log('output=', output);
      }
      break;

    case ("truncate"):
      output = truncateString(userInput, userInput2);
      console.log('output=', output);
      break;

    case ("titleCase"):
      output = titleCase(userInput);
      console.log('output=', output);
      break;
      
    default:
      //do nothing;
  }
  document.getElementById("output-area").innerHTML = output;
}

document.getElementById("dropdown").onchange = function() {dropdownChoice()};