package playground;

import atlantafx.base.theme.Styles;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import javafx.application.Application;
import javafx.beans.property.SimpleObjectProperty;
import javafx.beans.value.WritableValue;
import javafx.css.CssMetaData;
import javafx.css.Styleable;
import javafx.css.StyleableProperty;
import javafx.css.converter.PaintConverter;
import javafx.geometry.Point2D;
import javafx.scene.Cursor;
import javafx.scene.Scene;
import javafx.scene.control.ContextMenu;
import javafx.scene.control.MenuItem;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.Region;
import javafx.scene.paint.Color;
import javafx.scene.paint.Paint;
import javafx.scene.shape.Path;
import javafx.scene.shape.PathElement;
import javafx.scene.text.Text;
import javafx.scene.text.TextFlow;
import javafx.stage.Stage;
import org.jspecify.annotations.Nullable;
import util.Resources;

public class Launcher extends Application {

    static class SelectableText extends TextFlow {

        protected final Path wrappingPath = new Path();
        protected SimpleObjectProperty<ContextMenu> contextMenuProperty = new SimpleObjectProperty<>();

        protected int mouseDragStartPos = -1;
        protected int selectionStartPos = -1;
        protected int selectionEndPos = -1;
        protected boolean keepFocus;

        public SelectableText() {
            super();

            setCursor(Cursor.TEXT);
            setPrefWidth(Region.USE_PREF_SIZE);

            wrappingPath.setManaged(false);

            getStyleClass().add("selectable-text");
            initListeners();
        }

        private void initListeners() {
            setOnMousePressed(e -> {
                if (e.isPopupTrigger()) {
                    showPopupMenu(e);
                    return;
                }

                var hit = hitTest(new Point2D(e.getX(), e.getY()));

                keepFocus = false;
                removeSelection();

                if (e.isPrimaryButtonDown() && e.getClickCount() == 2) {
                    // TODO: Double-click selection
                    return;
                } else {
                    mouseDragStartPos = hit.getCharIndex();
                }

                // to be able to clear selection on focus lost we should request it first
                requestFocus();
            });

            setOnMouseDragged(e -> {
                var hit = hitTest(new Point2D(e.getX(), e.getY()));

                selectionStartPos = Math.min(mouseDragStartPos, hit.getCharIndex());
                selectionEndPos = Math.max(mouseDragStartPos, hit.getCharIndex());

                PathElement[] selectionRange = rangeShape(selectionStartPos, selectionEndPos);
                wrappingPath.getElements().setAll(selectionRange);

                requestFocus();
            });

            setOnMouseReleased(e -> {
                mouseDragStartPos = -1;
                if (e.isPopupTrigger()) {
                    showPopupMenu(e);
                }
            });

            contextMenuProperty.addListener((obs, old, val) -> {
                if (old != null) {
                    old.setOnHidden(null);
                }
                if (val != null) {
                    val.setOnHidden(e -> removeSelection());
                }
            });

            // width can be changed by changing the stage size via system shortcuts
            widthProperty().addListener((obs, old, val) -> removeSelection());

            // keep selection when context menu is called to perform an action on selected text
            focusWithinProperty().addListener((obs, old, val) -> {
                if (!val && !keepFocus) {
                    removeSelection();
                }
            });
        }

        public void setText(Text... text) {
            getChildren().setAll(wrappingPath);
            getChildren().addAll(text);
        }

        public void clear() {
            getChildren().setAll(wrappingPath);
        }

        public @Nullable String getSelectedTextAsString() {
            var content = getTextFlowContentAsString();
            return selectionStartPos > 0 && selectionEndPos > selectionStartPos
                ? content.substring(selectionStartPos, selectionEndPos)
                : null;
        }

        public ContextMenu getContextMenu() {
            return contextMenuProperty.get();
        }

        public SimpleObjectProperty<ContextMenu> contextMenuProperty() {
            return contextMenuProperty;
        }

        public void setContextMenu(@Nullable ContextMenu contextMenu) {
            this.contextMenuProperty.set(contextMenu);
        }

        protected StringBuilder getTextFlowContentAsString() {
            var sb = new StringBuilder();
            for (var node : getChildren()) {
                if (node instanceof Text t) {
                    sb.append(t.getText());
                }
            }
            return sb;
        }

        protected void removeSelection() {
            selectionStartPos = -1;
            selectionEndPos = -1;
            wrappingPath.getElements().clear();
        }

        protected void showPopupMenu(MouseEvent e) {
            var contextMenu = contextMenuProperty.get();
            if (contextMenu != null) {
                keepFocus = true;
                contextMenu.show(this, e.getScreenX(), e.getScreenY());
            }
        }

        ///////////////////////////////////////////////////////////////////////////
        // Styleable Properties                                                  //
        ///////////////////////////////////////////////////////////////////////////

        private static class StyleableProperties {

            private static final CssMetaData<SelectableText, Paint> HIGHLIGHT_FILL = new CssMetaData<>(
                "-fx-highlight-fill", PaintConverter.getInstance(), Color.TRANSPARENT
            ) {

                @Override
                public boolean isSettable(SelectableText c) {
                    return c.wrappingPath.fillProperty() == null || !c.wrappingPath.fillProperty().isBound();
                }

                @Override
                public StyleableProperty<Paint> getStyleableProperty(SelectableText c) {
                    var val = (WritableValue<Paint>) c.wrappingPath.fillProperty();
                    return (StyleableProperty<Paint>) val;
                }
            };

            private static final CssMetaData<SelectableText, Paint> HIGHLIGHT_STROKE = new CssMetaData<>(
                "-fx-highlight-stroke", PaintConverter.getInstance(), Color.TRANSPARENT
            ) {

                @Override
                public boolean isSettable(SelectableText c) {
                    return c.wrappingPath.strokeProperty() == null || !c.wrappingPath.strokeProperty().isBound();
                }

                @Override
                public StyleableProperty<Paint> getStyleableProperty(SelectableText c) {
                    var val = (WritableValue<Paint>) c.wrappingPath.strokeProperty();
                    return (StyleableProperty<Paint>) val;
                }
            };

            private static final List<CssMetaData<? extends Styleable, ?>> STYLEABLES;

            static {
                final List<CssMetaData<? extends Styleable, ?>> styleables =
                    new ArrayList<>(TextFlow.getClassCssMetaData());
                styleables.add(HIGHLIGHT_FILL);
                styleables.add(HIGHLIGHT_STROKE);
                STYLEABLES = Collections.unmodifiableList(styleables);
            }
        }

        public static List<CssMetaData<? extends Styleable, ?>> getClassCssMetaData() {
            return StyleableProperties.STYLEABLES;
        }

        @Override
        public List<CssMetaData<? extends Styleable, ?>> getCssMetaData() {
            return getClassCssMetaData();
        }
    }

    public static void main(String[] args) {
        launch();
    }

    @Override
    public void start(Stage stage) {
        var st = new SelectableText();
        st.getStylesheets().add(Styles.toDataURI(
            """
                .selectable-text {
                    -fx-highlight-fill: rgba(255, 0, 0, 0.25);
                    -fx-highlight-stroke: rgba(255, 0, 0, 0.25);
                }
                """
        ));
        st.setText(
            new Text("Lorem Ipsum ".repeat(20))
        );

        var copy = new MenuItem("Copy");
        copy.setOnAction(e -> System.out.println(st.getSelectedTextAsString()));

        var menu = new ContextMenu();
        menu.getItems().add(copy);
        st.setContextMenu(menu);

        var root = new BorderPane(st);

        var scene = new Scene(root, 800, 200);
        scene.getStylesheets().add(Resources.getResource("/index.css"));
        stage.setScene(scene);
        stage.show();
    }
}