var input = document.getElementById('todo-input');
var todoList = document.getElementById("todo-list");
var todos = [];

if(typeof(Storage) !== "undefined"){
    var localTodos = localStorage.getItem("todos");
    
    if(localTodos == null){
        //first run...
    } else {
        console.log("Existing todos found.");

        todos = JSON.parse(localTodos);
        console.log(todos);

        todos.forEach(element => {
            console.log(element);
            addTodo(element.text, element.complete);
        }); 
    }
} else {
    addTodo("There is no web storage support for this session", false);
}

window.onbeforeunload = function(){
    localStorage.clear();
    localStorage.setItem("todos", JSON.stringify(todos));
}

input.onkeyup = (e) => {
    if(e.keyCode == 13){
        addTodo();
        input.value = "";
    }
}

function addTodo(text, completed){
    var todoText = input.value;

    if(text){
        todoText = text;
    } else {
        //new element
        todos.push({
            "text": todoText, 
            "complete": completed
        }
        );
    }

    if(todoText == ""){
        return;
    }

    var newTodo = document.createElement("li");
    var newTodoDiv = document.createElement("div");

    var newTodoCheck = document.createElement("input");
    newTodoCheck.type = 'checkbox';
    newTodoCheck.onchange = (e) => {
        var index = Array.from(todoList.children).indexOf(e.target.parentNode.parentNode);
        console.log(index);
        todos[index].complete = e.target.checked;
        e.target.parentNode.parentNode.classList.toggle("complete");
    } 

    var newTodoContent = document.createElement("p");
    newTodoContent.innerHTML = todoText;
    
    if(completed){
        newTodoCheck.checked = true;
        newTodoContent.classList.add("complete");
    }

    var newTodoRemoveButton = document.createElement("button");
    newTodoRemoveButton.innerHTML = "&times"
    newTodoRemoveButton.onclick = removeTodo;

    newTodoDiv.classList.add("todo-item");
    newTodoDiv.appendChild(newTodoCheck);
    newTodoDiv.appendChild(newTodoContent);
    newTodoDiv.appendChild(newTodoRemoveButton);

    newTodo.appendChild(newTodoDiv);

    
    if(completed){
        newTodo.classList.toggle("complete")
    }

    todoList.appendChild(newTodo);

}

function removeTodo(e){
    var index = Array.from(todoList.children).indexOf(e.target.parentNode.parentNode);
    console.log(index);

    todos.splice(index,1);
    e.target.parentNode.parentNode.remove();

}

function resetLocalStorage(){
    todos = [];
    localStorage.clear();
    location.reload();
}