$(document).ready(function(){

    $("#addNoteDiv").on('click', function() {

        // Listener für den Plus Button zum hinzufügen von Note Forms.

        console.log("Add")

        createForm();
    })

    $('#allNotesDiv').on('click', 'button', async function() {
        
        // Listener für den Save Button zum speichern von Note Forms.

        console.log("Save")

        let buttonId = (this.id).split("_")[1];
        let type = (this.id).split("_")[0];
        try {
            if (type == 'saveNoteButton'){
                // Speichern einer neuen Note.
                await saveNoteObject(buttonId);
            } else if (type == 'editNoteButton'){
                // Editieren einer gespeicherten Note.
                await saveNoteObject(buttonId, true);
            }
        } catch(err){
            alert(err);
        }
    })

    $('#noteStorage').on('click', 'button', async function() {
        
        // Listener für den Delete Button zum Löschen einer Note aus dem Note Browser und Local Storage.

        console.log("Delete")
        
        let buttonId = (this.id).split("_")[1];
        try {
            await removeBrowserItem(buttonId);
        } catch(err) {
            alert(err);
        }
    })

    $("#refreshButton").on('click', async function() {
        
        // Listener für den Refresh Button zum aktualisieren der gespeicherten Notes.

        console.log("Refresh")
        
        createLoadingSign(id="", append="noteStorage");
        enableLoadingSign(id="");
        await sleep(2000);
        disableLoadingSign(id="");
        try {
            await refreshBrowser();
        } catch(err){
            alert(err);
        } 
    })
})

let id=1;

function createForm(){

    // Erstellt eine NoteForm und initialisiert die OnClick-Listener auf den Buttons der Form

    id++;

    console.log("createForm() "+id)
    
    let wrapper = document.createElement("div");
    wrapper.setAttribute('id', "note"+id);
    wrapper.style.margin = '2.5px';
    let inputsWrapper = document.createElement("div");
    inputsWrapper.setAttribute('class', "noteDiv");

    let inputDiv = document.createElement("div");
    let input = document.createElement("input");
    let deleteButton = document.createElement('button');
    input.setAttribute('type', "text");
    input.setAttribute('name',"noteTitle");
    input.setAttribute('id', "inputTitle"+id);
    input.setAttribute('placeholder', "Enter title...");
    input.style.marginBottom='5px';
    deleteButton.style.marginLeft = '2px';
    deleteButton.innerHTML = "X";
    deleteButton.setAttribute('id', "deleteForm_" + id);
    deleteButton.setAttribute('onClick', "deleteForm(this.id)");
    deleteButton.setAttribute('class', "right");
    inputDiv.appendChild(input);
    inputDiv.appendChild(deleteButton);
    
    let textAreaDiv = document.createElement("div");
    let textarea = document.createElement("textarea");
    textarea.setAttribute('name',"noteText");
    textarea.setAttribute('id', "noteText"+id);
    textarea.setAttribute('placeholder', "Enter notes...");
    textarea.style.width='300px';
    textarea.style.height='150px';
    textarea.style.boxSizing='border-box';
    textAreaDiv.appendChild(textarea);

    let saveNoteButton = document.createElement("button");
    saveNoteButton.setAttribute('type',"button");
    saveNoteButton.setAttribute('id',"saveNoteButton_"+id);
    saveNoteButton.innerHTML = 'Save';

    inputsWrapper.appendChild(inputDiv);
    inputsWrapper.appendChild(textAreaDiv);
    inputsWrapper.appendChild(saveNoteButton);
    wrapper.appendChild(inputsWrapper);

    document.getElementById('allNotesDiv').appendChild(wrapper);
}

function deleteForm(idName){

    // Aktiviert durch OnClickListener auf dem X-Button innerhalb der Form zum Schließen der Form

    console.log("deleteForm() " + id);

    id = idName.split("_")[1];
    document.getElementById("note"+id).remove();
}

function createFormWithSavedContent(item, id){
    
    // Holt eine gespeicherte Form aus dem Speicher und erstellt erneut eine NoteForm und initialisiert die OnClick-Listener auf den Buttons der Form

    console.log("createFormWithSavedContent() "+ id)

    let wrapper = document.createElement("div")
    wrapper.setAttribute('id', "note"+id)
    let inputsWrapper = document.createElement("div")
    inputsWrapper.setAttribute('class', "noteDiv");

    let inputDiv = document.createElement("div");
    let input = document.createElement("input");
    let deleteButton = document.createElement('button');
    input.setAttribute('type', "text");
    input.setAttribute('name',"noteTitle");
    input.setAttribute('id', "inputTitle"+id);
    input.setAttribute('value', item.title);
    input.style.marginBottom='5px';
    deleteButton.style.marginLeft = '2px';
    deleteButton.innerHTML = "X";
    deleteButton.setAttribute('id', "deleteForm_" + id);
    deleteButton.setAttribute('onClick', "deleteForm(this.id)");
    inputDiv.appendChild(input);
    inputDiv.appendChild(deleteButton);
    
    let textAreaDiv = document.createElement("div");
    let textarea = document.createElement("textarea");
    textarea.setAttribute('name',"noteText");
    textarea.setAttribute('id', "noteText"+id);
    textarea.setAttribute('value', item.text);
    textarea.innerHTML = item.text;
    textarea.style.width='300px';
    textarea.style.height='150px';
    textarea.style.boxSizing='border-box';
    textAreaDiv.appendChild(textarea);

    let editNoteButton = document.createElement("button");
    editNoteButton.setAttribute('type',"button");
    editNoteButton.setAttribute('id',"editNoteButton_"+id);
    editNoteButton.innerHTML = 'Save';

    inputsWrapper.appendChild(inputDiv);
    inputsWrapper.appendChild(textAreaDiv);
    inputsWrapper.appendChild(editNoteButton);
    wrapper.appendChild(inputsWrapper);

    document.getElementById('allNotesDiv').appendChild(wrapper);
}

let ctr;

async function sleep(ms) {

    // Best Practice Variante zum pausieren von Code
    // Soll hier Prozesse simulieren die bei synchronem Code zu I/O-Blocking führen würden

    console.log("sleep() " + ms);

    try {
        return new Promise(resolve => setTimeout(resolve, ms));
    }
    catch (alert) {
        return alert(alert);
    }
}

async function removeNote(id){

    // Löscht eine Note aus dem Note Browser

    console.log("removeNote() " + id);

    return new Promise((resolve, reject) => {
        try {
            localStorage.removeItem('noteObj' + id);
            removeBrowserItem(id);
            resolve();
        } catch(err) {
            reject(err);
        }
    });
}

async function saveNote(id){

    console.log("saveNote() " + id);

    return new Promise((resolve, reject) => {
        try {
            let noteTitle = document.getElementById('inputTitle' + id).value;
            let noteText = document.getElementById('noteText' + id).value;
            let noteObj = {
                idK: id,
                title: noteTitle,
                text: noteText
            };
            let noteObj_serialized = JSON.stringify(noteObj); //stringify noteObj so it is displayed properly when set to local Storage
            localStorage.setItem("noteObj" + id, noteObj_serialized);
            resolve(noteObj);
        } catch(err) {
            reject(err);
        }
    });
}

async function refreshBrowser(){

    console.log("refreshBrowser()");

    return new Promise((resolve, reject) => {
        try {
            let noteStorage = [];
            let keys = Object.keys(localStorage);
            let i = keys.length;
            while (i--) {
                noteStorage.push(localStorage.getItem(keys[i]));
            }
            let parentNode = document.getElementById('noteStorage');
            parentNode.innerHTML = '';
            noteStorage.forEach(element => {
                createBrowserItem(JSON.parse(element));
            });
            resolve();
        } catch(err) {
            reject(err);
        }
    });
}

async function saveNoteObject(id, overwrite=false){
    
    console.log("saveNoteObject() " + id + " " + overwrite);
    
    createLoadingSign(id, append="note")
    enableLoadingSign(id);
    await sleep(10000) //sleep() simulates the delay that would occur when there is a remote server access or similar, 
                       //so instead of sleep would be e.g. saveToRemoteServer()...
                       //the leftover code of the async function is executed after the delay
    disableLoadingSign(id);

    try {
        if (overwrite == true){
            await removeNote(id);
        }
        let obj = await saveNote(id);
        createBrowserItem(obj);
    } catch(err){
        alert(err)
    }
    document.getElementById("note"+id).remove();
}

function enableLoadingSign(id){

    console.log("enableLoadingSign() " + id);

    let target = 'loadSign'+id;
    document.getElementById(target).style.display = "block";
}

function disableLoadingSign(id){

    console.log("disableLoadingSign() " + id);

    let target = 'loadSign'+id;
    let sign = document.getElementById(target);
    sign.style.display = "none";
    sign.parentNode.removeChild(sign);
}

function createLoadingSign(id, append){

    console.log("createLoadingSign() " + id);

    let target = 'loadSign'+id;
    let appendTo = append+id;
    let loadingSign = document.createElement('div');
    let loadingSignWrapper = document.createElement('div');
    loadingSign.setAttribute('class', 'loader')
    loadingSign.setAttribute('id', target);
    loadingSignWrapper.appendChild(loadingSign);
    document.getElementById(appendTo).appendChild(loadingSignWrapper);
}

function createBrowserItem(item){

    console.log("createBrowserItem() " + item);

    let wrapperDiv = document.createElement('div');
    let browserItem = document.createElement('div');
    let deleteButton = document.createElement('button');
    wrapperDiv.setAttribute('class', 'browserElement');
    browserItem.innerHTML = item.title;
    deleteButton.style.marginLeft = '2px';
    deleteButton.innerHTML = "X";
    browserItem.setAttribute('id', "browserItem_"+item.idK);
    browserItem.setAttribute('onClick', "getSavedNote(this.id)");
    deleteButton.setAttribute('id', "deleteItem_" + item.idK);
    wrapperDiv.appendChild(browserItem);
    wrapperDiv.appendChild(deleteButton);
    document.getElementById('noteStorage').appendChild(wrapperDiv);
}

async function removeBrowserItem(id){

    console.log("removeBrowserItem() " + id);

    return new Promise((resolve, reject) => {
        try {
            localStorage.removeItem('noteObj' + id);
            document.getElementById("browserItem_" + id).remove();
            document.getElementById("deleteItem_" + id).remove();
            resolve();
        } catch(err) {
            reject(err);
        } 
    });
}

async function getItemFromStorage(idTmp){

    console.log("getItemFromStorage() " + idTmp);

    return new Promise((resolve, reject) => {
        try {
            let item = JSON.parse(localStorage.getItem('noteObj'+idTmp));
            resolve(item);
        } catch (err) {
            reject(err);
        }
    });
}


async function getSavedNote(id){

    console.log("getSavedNote() "+ id);

    createLoadingSign("", "allNotesDiv");
    enableLoadingSign("");
    await sleep(5000);
    disableLoadingSign("");
    let idTmp = id.split("_")[1];
    try {
        let item = await getItemFromStorage(idTmp);
        createFormWithSavedContent(item, idTmp);
    } catch(err) {
        alert(err)
    }
}