// Style //

const machineStyles = document.getElementById("upp2025_w02");
machineStyles.disabled = false;

// Extra rows //

const rows = document.getElementById("worksheet").children[0];
const addrowsBtn = document.getElementById("addrows");

addrowsBtn.addEventListener('click', function() {
    let last = rows.children[rows.children.length - 2];
    for (let i = 1; i <= 10; ++i) {
        let row = last.cloneNode(true);
        row.children[0].innerText = Number(row.children[0].innerText) + i
        rows.insertBefore(row, rows.children[rows.children.length - 1]);
    }
    memoryRefresh();
});

// Execution //

const INPUT1 = document.getElementById("input1");
const INPUT2 = document.getElementById("input2");
const A = document.getElementById("regA");
const B = document.getElementById("regB");

const errorMsg = document.getElementById("errorMsg");

var speed = 1000;
var running = false;
var stop = false;

var memory = null;
var memoryLocation = -1;
var parametrisedCommand = null;

function memoryRefresh() {
    memory = document.querySelectorAll("#worksheet tr:not(:first-of-type) > td:first-of-type:not(:last-of-type)");
    memoryLocation = memory.length;
}
memoryRefresh();

function executeInit() {
    running = true;
    A.innerText = 0;
    B.innerText = 0;
    errorMsg.innerText = '';

    for (let i = 0; i < memory.length; ++i) {
        memory[i].innerText = memory[i].innerText
                                .trim()
                                .replace(' ', '')
                                .replace('\n', '');
        memory[i].classList.remove('error');
        memory[i].classList.remove('selected');
    }
}

function executeDeinit() {
    memoryLocation = memory.length;
    parametrisedCommand = null;
    stop = false;
    running = false;
    stopresumeBtn.innerText = 'Спри';
}

function expectedCommand() {
    if (parametrisedCommand !== null) {
        error('Очакваше се число, не команда!');
        return false;
    }
    return true;
}

function expectedNumber() {
    if (parametrisedCommand === null) {
        error('Очакваше се команда!');
        return false;
    }
    if (isNaN(toNumber(memory[memoryLocation].innerText))) {
        error('Очакваше се валидно число!');
        return false;
    }
    return true;
}

function error(msg) {
    errorMsg.innerText = msg;
    memory[memoryLocation].classList.add('error');
    executeDeinit();
}

function toNumber(text) {
         if (text === 'INPUT1') text = INPUT1.innerText;
    else if (text === 'INPUT2') text = INPUT2.innerText;

    return Number(text);
}

function execute() {
  if (stop) {
    running = false;
    return;
  }

  // After cell was set
  if (memoryLocation < memory.length) {
    memory[memoryLocation].classList.remove('selected');

    switch (parametrisedCommand) {
        case null: break;
        case 'ASUM':
            if (!expectedNumber()) return;
            A.innerText = Number(A.innerText) + toNumber(memory[memoryLocation].innerText);
            break;
        case 'ASUBTRACT':
            if (!expectedNumber()) return;
            A.innerText = Number(A.innerText) - toNumber(memory[memoryLocation].innerText);
            break;
        case 'BSUM':
            if (!expectedNumber()) return;
            B.innerText = Number(B.innerText) + toNumber(memory[memoryLocation].innerText);
            break;
        case 'BSUBTRACT':
            if (!expectedNumber()) return;
            B.innerText = Number(B.innerText) - toNumber(memory[memoryLocation].innerText);
            break;
        case 'GOTOBZ':
            if (!expectedNumber()) return;
            if (Number(B.innerText) === 0)
              memoryLocation = toNumber(memory[memoryLocation].innerText) - 2;
            break;
        case 'GOTOBN':
            if (!expectedNumber()) return;
            if (Number(B.innerText) >= 0)
              memoryLocation = toNumber(memory[memoryLocation].innerText) - 2;
            break;
    }

    if (parametrisedCommand === null) {
        switch (memory[memoryLocation].innerText) {
            case '':
                executeDeinit();
                return;
            case 'ASHOW':
                alert(A.innerText);
                break;
            case 'ASUM':
            case 'ASUBTRACT':
            case 'GOTOBZ':
            case 'GOTOBN':
            case 'BSUM':
            case 'BSUBTRACT':
                if (!expectedCommand()) return;
                parametrisedCommand = memory[memoryLocation].innerText;
                break;
            default:
                error('Невалидна команда!');
                return;
        }
    }
    else parametrisedCommand = null;
  }
  // On execution start
  else {
    executeInit();
  }

  memoryLocation = (memoryLocation + 1) % (memory.length + 1);
  memory[memoryLocation].classList.add('selected');

  if (memoryLocation < memory.length) {
    setTimeout(execute, speed);
  }
}

const execBtn = document.getElementById("execute");
execBtn.addEventListener('click', function() {
  if (!running)
    executeDeinit();
  if (memoryLocation == memory.length)
    execute();
});

const stopresumeBtn = document.getElementById('stopresume');
stopresumeBtn.addEventListener('click', function() {
    if (stop && !running) {
        stop = false;
        running = true;
        stopresumeBtn.innerText = 'Спри';
        execute();
    }
    else if (!stop && running) {
        stop = true;
        stopresumeBtn.innerText = 'Продължи';
    }
});

// Disallow newline
function preventCharacters(evt) {
    if (evt.keyCode == 13 || evt.keyCode == 32)
        evt.preventDefault();
}
for (let i = 0; i < memory.length; ++i) {
    memory[i].addEventListener('keydown', preventCharacters);
}

// Speed //

const rbFast = document.getElementById('speedChoice1');
const rbSlow = document.getElementById('speedChoice2');

rbFast.addEventListener('change', function() {
    speed = rbFast.value;
});
if (rbFast.checked) speed = rbFast.value;

rbSlow.addEventListener('change', function() {
    speed = rbSlow.value;
});
if (rbSlow.checked) speed = rbSlow.value;

// Save/load //

const saveBtn = document.getElementById('save');
const loadBtn = document.getElementById('load');

saveBtn.addEventListener('click', function() {
    let contents = '';
    for (let i = 0; i < memory.length; ++i) {
        contents += memory[i].innerText + '\n';
    }

    let now = new Date();
    let datetime =
      now.getFullYear().toString()
      + (now.getMonth() < 10 ? '0' : '')
      + now.getMonth().toString()
      + (now.getDate() < 10 ? '0' : '')
      + now.getDate()
      + "_"
      + now.getHours()
      + now.getMinutes();

    // Thanks https://stackoverflow.com/a/79383186
    const download = document.createElement('a');
    download.href = URL.createObjectURL(new Blob([contents], { type: 'text/csv' }));
    download.download = 'Таблица_' + datetime + '.csv';
    download.click();

    URL.revokeObjectURL(download.href);
});

function loadMemory(text) {
    let rows = text.split("\n");
    while (memory.length < rows.length)
        addrowsBtn.click();

    for (let i = 0; i < rows.length; ++i) {
        memory[i].innerText = rows[i].split(',')[0];
    }
}

loadBtn.addEventListener('click', function() {
    const upload = document.createElement('input');
    upload.type = 'file';
    upload.accept = 'text/csv';
    upload.click();

    upload.addEventListener('change', function(e) {
        let file = e.target.files[0];
        if (!file) return;

        let reader = new FileReader();
        reader.readAsText(file);

        reader.addEventListener('load', function(e) {
            loadMemory(e.target.result);
        });
    });
});