function prepareForExport(doc, settings = settings) {
    let states = JSON.parse(JSON.stringify(doc.states));

    states.forEach(state => {
        delete state.mouseOffsetX;
        delete state.mouseOffsetY;
        delete state.activeTime;
        delete state.isActive;
    });

    let _connections = JSON.parse(JSON.stringify(doc.connections)).map((conn, index) => {
        conn.type = doc.connections[index].constructor.name;
        return conn;
    });

    _connections = _connections.map(conn => {
        switch(conn.type) {
            case 'Connection':
                conn.stateA = conn.stateA.id;
                conn.stateB = conn.stateB.id;
                break;
            case 'StartConnection':
                conn.state = conn.state.id;
                break;
            case 'SelfConnection':
                conn.state = conn.state.id;
                break;
        }
        return conn;
    });

    const _doc = JSON.parse(JSON.stringify(doc));
    _doc.states = states;
    _doc.connections = _connections;

    delete _doc.unsaved;
    delete _doc.lastSavedHash;
    delete _doc.element;

    const _settings = JSON.parse(JSON.stringify(settings));

    delete _settings.colors.getColor;

    return {
        document: _doc,
        settings: _settings,
    };
}

function exportToJson(doc, _settings = settings) {
    return JSON.stringify(prepareForExport(doc, _settings));
}

function parseFromJson(json) {
    const data = JSON.parse(json);

    const doc = Object.assign(new FSMDocument(''), data.document);

    doc.states = doc.states.map(state => Object.assign(new State(0, 0), state));
    doc.connections = doc.connections.map(connection => {
        switch(connection.type) {
            case 'Connection':
                connection = Object.assign(new Connection(null, null), connection);

                connection.stateA = doc.states.find(state => state.id === connection.stateA);
                connection.stateB = doc.states.find(state => state.id === connection.stateB);

                break;
            case 'SelfConnection':
                connection = Object.assign(new SelfConnection(null), connection);

                connection.state = doc.states.find(state => state.id === connection.state);

                break;
            case 'StartConnection':
                connection = Object.assign(new StartConnection(), connection);

                connection.state = doc.states.find(state => state.id === connection.state);

                break;
        }

        delete connection.type;
        return connection;
    });

    doc.lastSavedHash = doc.hashCode();

    return {
        document: doc,
        settings,
    };
}

function importFromJson(json) {
    const doc = parseFromJson(json);

    addDocument(doc.document);
    switchDocument(doc.document);
}

function exportToFile() {
    if(activeDocument === null) {
        return;
    }

    const document = documents[activeDocument];
    const name = `${new Date(document.createdAt).toLocaleDateString()} - ${document.name || 'Unbenannt'}.fsm`;
    const json = exportToJson(document);
    downloadFile(name, json, 'application/json');
}

function downloadFile(name, content, type) {
    const element = document.createElement('a');

    element.setAttribute('href', `data:${type};base64,${btoa(content)}`);
    element.setAttribute('download', name);

    element.style.display = 'none';
    document.body.appendChild(element);

    element.click();
    document.body.removeChild(element);
}

function saveToLocalStorage() {
    if(activeDocument === null) {
        return;
    }

    const newDoc = documents[activeDocument];
    const data = getLocalStorageEntries();

    const index = data.findIndex(entry => entry.document.id === newDoc.id);

    if(index !== -1) {
        data[index] = {
            document: newDoc,
            settings,
        };
    } else {
        data.push({
            document: newDoc,
            settings,
        });
    }

    const newData = data.map(entry => prepareForExport(entry.document, entry.settings));

    localStorage.setItem('documents', JSON.stringify(newData));
}

function getLocalStorageEntries() {
    const entries = JSON.parse(localStorage.getItem('documents'));
    return !!entries ? entries.map(entry => parseFromJson(JSON.stringify(entry))) : [];
}

function openFromLocalStorage(id) {
    const entry = getLocalStorageEntries().find(entry => entry.document.id === id);
    addDocument(entry.document);
    switchDocument(entry.document);
}