let people = [];

/********************************************************
  1) Take weight in pounds and divide by 2.2
  2) Multiply that # depending on your age:
     a) Younger than 30... by 30
     b) Between 30 and 55... by 35
     c) Older than 55... by 30
  3) Divide that sum by 28.3 
     (this gives you the total # of ounces you
      should drink each day)
  4) Divide # by 8 to see your result in cups
  
  5) Add an extra .8 oz per minute of exercise
  
  My wife got the info from the goodhousekeeping.com web site
  Sept 8, 2019
  
  https://www.goodhousekeeping.com/health/diet-nutrition/a46956/how-much-water-should-i-drink/
********************************************************/

function pageSetup(event) {
  const addPersonBtnNd = document.getElementById("addPersonBtn");
  addPersonBtnNd.addEventListener('click', addPerson);
  
  if (localStorage.getItem("people")) {
    sData = localStorage.getItem("people");
    people = JSON.parse(sData);
    displayPeople();
  } else {
    addPerson();
  } // end if/else
  
  setTimeout(firstFocus, 20);
} // end of function pageSetup()


function firstFocus() {
  const age1Nd = document.getElementById("age0");
  age1Nd.focus();
} // end of function firstFocus()


//
function addPerson(event) {
  const person = {};
  person.name = "Person "+(people.length+1);
  person.weight = 150;
  person.age = 35;
  person.minutesExercise = 0;
  person.oz = 0;  // will be calced later
  person.cups = 0;   // will be calced later
  people.push(person);
  savePeople();
  displayPeople();
} // end of function addPerson()


function displayPeople() {
  const nMax = people.length;
  const s=[];
  const Q = '"';
  
  for (let n=0;n<nMax;n++) {
    const person = people[n];
    s.push("<div class='person' ")
    s.push("style="+Q);
    let nLeft = (n * 335 + 10);
    s.push("left:"+ (nLeft) +"px;");
    s.push(Q);
    s.push(">")
      s.push("<span class='personNameLbl'>Name:</span>")
      s.push("<input class='personNameInput'id='pname"+n+"'");
      s.push(" data-idx="+Q+n+Q+" ");
      s.push(">")
      s.push("<span class='ageLbl' title='Age in years...'>Age:</span>")
      s.push("<input class='ageInput' id='age"+n+"'")
      s.push(" data-idx="+Q+n+Q+" ");
      s.push(" value='"+person.age+"'");
      s.push(">");
      s.push("<span class='weightLbl' title='Weight in Pounds'>Weight (lbs):</span>")
      s.push("<input class='weightInput' id='lbs"+n+"'");
      s.push(" data-idx="+Q+n+Q+" ");
      s.push(" value='"+person.weight+"'");
      s.push(">");
    
      let s1=[];
      s.push("<span class='minutesLbl' title='Minutes of Exercise per day'>Minutes of Exercise:</span>");
      s.push("<input class='minutesInput' id='mins"+n+"'")
      s.push(" data-idx="+Q+n+Q+" ");
      s.push(" value='"+person.minutesExercise+"'");
      s.push(">");

   // alert(s1.join('\n'));
      s.push("<span class='waterToDrinkLbl'>Amount of Water to Drink:</span>");
      s.push("<span class='ozsLbl'>In Ounces:</span>");
    
      s.push("<input class='ozInput' id='oz"+n+"'");
      s.push(" data-idx="+Q+n+Q+" ");
      s.push(" readonly value='"+person.oz+"'");
      s.push(">");
    
      s.push("<span class='cupsLbl'>In 8oz Cups:</span>");
    
      s.push("<input class='cupsInput' id='cups"+n+"'");
      s.push(" data-idx="+Q+n+Q+" ");
      s.push(" readonly value='"+person.cups+"'");
      s.push(">");
    
      if (nMax>1) {
        s.push("<button class='delBtn' ");
        s.push("id='delBtn"+n+"' ");
        s.push(">Delete Person</button>");
      } // end if
    
    s.push("</div>"); // person div
  } // next n
  
  const peopleNd = document.getElementById("people");
  peopleNd.innerHTML = s.join("");
  
  for (let n=0;n<nMax;n++) {
    const person = people[n];
    const nameNd = document.getElementById("pname"+n);
    nameNd.value = person.name;
    nameNd.addEventListener('keyup', updatePersonName);
    
    const ageNd = document.getElementById("age"+n);
    ageNd.addEventListener('keydown', checkIntInput);
    ageNd.addEventListener('keyup', updatePersonAge);
    
    const lbsNd = document.getElementById("lbs"+n);
    lbsNd.addEventListener('keydown', checkIntInput);
    lbsNd.addEventListener('keyup', updatePersonWeight);
    
    const minsNd = document.getElementById("mins"+n);
    minsNd.addEventListener('keydown', checkIntInput);
    minsNd.addEventListener('keyup', updatePersonMinutes);
    
    if (nMax>1) {
      const delBtnNd = document.getElementById("delBtn"+n);
      delBtnNd.addEventListener('click', delPerson); // click event handler for Delete button
    } // end if
    
    doCalc(n);
  } // next n
  
} // end of function displayPeople()



function doCalc(nIndex) {
  const person = people[nIndex];
  const ageInputNd = document.getElementById("age"+nIndex);
  const nAge = ageInputNd.value - 0;
  const weightInputNd = document.getElementById("lbs"+nIndex);
  const nWeight = weightInputNd.value - 0;
  const minutesInputNd = document.getElementById("mins"+nIndex);
  const nMinutes = minutesInputNd.value - 0; // daily minutes of exercise
  let v1 = nWeight / 2.2;
  
  if (nAge < 30 || nAge > 55) {
    v1 = v1 * 30.0;
  } else {
    v1 = v1 * 35.0;
  } // end if/else
  
  let nBaseOzToDrink = v1 / 28.3;
  let nTotOzToDrink = nBaseOzToDrink + (nMinutes * 0.8);
  nTotOzToDrink = nTotOzToDrink.toPrecision(4);
  let nTotCups = nTotOzToDrink / 8.0;
  nTotCups = nTotCups.toPrecision(3);
  
  person.oz = nTotOzToDrink;
  person.cups = nTotCups;
  
  const ozInputNd = document.getElementById("oz"+nIndex);  
  ozInputNd.value = person.oz;
  
  const cupsInputNd = document.getElementById("cups"+nIndex);  
  cupsInputNd.value = person.cups;
  
} // end of function doCalc()


function updatePersonName(event) {
  const inp = event.target;
  const nIdx = inp.dataset.idx-0;
  const person = people[nIdx];
  person.name = inp.value;
  savePeople();
} // end of function 



function updatePersonAge(event) {
  const inp = event.target;
  const nIdx = inp.dataset.idx-0;
  const person = people[nIdx];
    
  person.age = inp.value - 0;
  doCalc(nIndex);
  savePeople();
} // end of function updatePersonAge()



function updatePersonWeight(event) {
  const inp = event.target;
  const nIdx = inp.dataset.idx-0;
  const person = people[nIdx];
    
  person.weight = inp.value - 0;
  doCalc(nIndex);
  savePeople();
  
} // end of function updatePersonWeight()



function updatePersonMinutes(events) {
  const inp = event.target;
  const nIdx = inp.dataset.idx-0;
  const person = people[nIdx];
    
  person.minutesExercise = inp.value - 0;
  doCalc(nIndex);
  savePeople();
} // end of function updatePersonMinutes()


function delPerson(event) {
  const btn = event.target;
  const nIdx = btn.dataset.idx-0;
  people.splice(nIdx,1);
  savePeople();
  displayPeople();
} // end of function delPerson()


function savePeople() {
  const sData = JSON.stringify(people);
  localStorage.setItem("people", sData);
} // end of function savePeople()


// make sure keyboard input is only of
// integer digits or the backspace character
// (Event handler for keydown event on integer text boxes)
function checkIntInput(event) {
  const kc = event.keyCode;
  const BACKSPACE = 8; // don't have to worry about the Tab key!

  let sChar = String.fromCharCode(kc);
  const sValidChars = "0123456789";

  // handle numbers entered from numeric keypad on keyboard:
  if (kc > 95 && kc < 106) {
    sChar = (kc - 96)+"";
  } // end if
  
  if (sValidChars.indexOf(sChar) === -1 && kc !== BACKSPACE) {
    // not a correct character... don't allow it to be accepted as part of the input!
    event.stopPropagation();
    event.preventDefault();  
    event.returnValue = false;
    event.cancelBubble = true;
    return false;
  } // end if

  
} // end of function checkIntInput()


/****************************************************************************************
   below was written because the Number.toPrecision() method does Not work quite the way 
   I need it to!!
 ****************************************************************************************/
function roundToPrecision(nNum,nDecPrec) {
  let sNum = nNum+"";
  let nPos = sNum.indexOf(".");
  
  if (nPos === -1) {
    // if no decimal we are done!
    return nNum;
  } // end if
  
  let nCurDecPrec = sNum.length - nPos - 1; // calc number's current decimal precision
  if (nCurDecPrec<=nDecPrec) {
    // actual precision of number is less than or equal to specified precision
    // so return the original number!
    return nNum;
  } // end if
  
} // end of function roundToPrecision()


window.addEventListener('load', pageSetup);