package ctbrec.ui.tabs.logging;

import java.time.Instant;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
import java.util.Collections;
import java.util.LinkedList;
import java.util.stream.Collectors;

import com.google.common.eventbus.Subscribe;

import ch.qos.logback.classic.spi.IThrowableProxy;
import ch.qos.logback.classic.spi.LoggingEvent;
import ch.qos.logback.classic.spi.StackTraceElementProxy;
import ctbrec.event.EventBusHolder;
import ctbrec.ui.controls.SearchBox;
import javafx.application.Platform;
import javafx.beans.property.SimpleStringProperty;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.geometry.Insets;
import javafx.scene.control.Tab;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.layout.BorderPane;

public class LoggingTab extends Tab {

    private static final int HISTORY_LENGTH = 10_000;
    private SearchBox filter = new SearchBox();
    private TableView<LoggingEvent> table = new TableView<>();
    private ObservableList<LoggingEvent> history = FXCollections.observableList(Collections.synchronizedList(new LinkedList<>()));
    private ObservableList<LoggingEvent> filteredEvents = FXCollections.observableArrayList();
    private DateTimeFormatter timeFormatter = DateTimeFormatter.ISO_LOCAL_DATE_TIME;
    private volatile boolean tabClosed = false;
    private Object eventBustSubscriber = new Object() {
        @Subscribe
        public void publishLoggingEevent(LoggingEvent event) {
            if (!tabClosed) {
                Platform.runLater(() -> {
                    history.add(event);
                    if (history.size() > HISTORY_LENGTH - 1) {
                        history.remove(0);
                    }
                    filter();
                });
            }
        }
    };

    private void filter() {
        filteredEvents.clear();
        filteredEvents.addAll(history.stream().filter(evt -> {
            String q = filter.getText().toLowerCase();
            return evt.getLevel().toString().toLowerCase().contains(q)
                    || createLogMessage(evt).toLowerCase().contains(q);
        }).collect(Collectors.toList()));
    }

    public LoggingTab() {
        setText("Logging");
        subscribeToEventBus();

        table = new TableView<>(filteredEvents);

        int idx = 0;
        TableColumn<LoggingEvent, String> level = createTableColumn("Level", 65, idx++);
        level.setCellValueFactory(cdf -> new SimpleStringProperty(cdf.getValue().getLevel().toString()));
        table.getColumns().add(level);

        TableColumn<LoggingEvent, String> time = createTableColumn("Timestamp", 200, idx++);
        time.setCellValueFactory(cdf -> {
            Instant instant = Instant.ofEpochMilli(cdf.getValue().getTimeStamp());
            return new SimpleStringProperty(instant.atZone(ZoneId.systemDefault()).format(timeFormatter));
        });
        table.getColumns().add(time);

        TableColumn<LoggingEvent, String> msg = createTableColumn("Message", 2000, idx++);
        msg.setCellValueFactory(cdf -> new SimpleStringProperty(createLogMessage(cdf.getValue())));
        table.getColumns().add(msg);

        BorderPane layout = new BorderPane();
        BorderPane.setMargin(table, new Insets(10));
        BorderPane.setMargin(filter, new Insets(10, 10, 0, 10));
        layout.setCenter(table);
        layout.setTop(filter);

        setContent(layout);
        setOnClosed(evt -> {
            EventBusHolder.BUS.unregister(eventBustSubscriber);
            tabClosed = true;
        });

        filter.setPromptText("Search");
        filter.textProperty().addListener( (observableValue, oldValue, newValue) -> filter());
    }

    private String createLogMessage(LoggingEvent evt) {
        StringBuilder sb = new StringBuilder(evt.getFormattedMessage());
        if(evt.getThrowableProxy() != null) {
            IThrowableProxy throwableProxy = evt.getThrowableProxy();
            sb.append('\n').append(throwableProxy.getClassName()).append(':').append(' ').append(throwableProxy.getMessage());
            for (StackTraceElementProxy step : throwableProxy.getStackTraceElementProxyArray()) {
                sb.append('\n').append('\t').append(step.getSTEAsString());
            }
        }
        return sb.toString();
    }

    private <T> TableColumn<LoggingEvent, T> createTableColumn(String text, int width, int idx) {
        TableColumn<LoggingEvent, T> tc = new TableColumn<>(text);
        tc.setPrefWidth(width);
        tc.setUserData(idx);
        return tc;
    }

    private void subscribeToEventBus() {
        EventBusHolder.BUS.register(eventBustSubscriber);
    }
}