PAIR/src/main/java/com/pair/ui/QuizPage.java

// com/ui/QuizPage.java
package com.pair.ui;

import com.pair.model.ChoiceQuestion;
import com.pair.service.QuizService;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Node;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.scene.text.Font;
import javafx.scene.text.FontWeight;

import java.util.List;

public class QuizPage extends NavigablePanel {

    private final QuizService quizService;

    private final Label titleLabel = new Label("中小学数学答题系统");
    private final Label progressLabel = new Label("完成 0/10");
    private final Label questionLabel = new Label("题目加载中...");
    private final ToggleGroup optionGroup = new ToggleGroup();
    private final RadioButton[] options = new RadioButton[4];
    private final Button prevButton = new Button("上一题");
    private final Button nextButton = new Button("下一题");
    private final Button submitButton = new Button("交卷");

    // 题目导航矩阵容器
    private final GridPane questionNavGrid = new GridPane();
    private int totalQuestions = 10; // 默认10题，由外部设置
    private int currentQuestionIndex = 0; // 当前题号（0-based）

    public QuizPage(Runnable onBack, QuizService quizService) {
        super(onBack);
        this.quizService = quizService;
        initializeContent();
    }

    @Override
    protected void buildContent() {
        // 设置整体布局：BorderPane
        this.setPadding(new Insets(20));
        this.setStyle("-fx-background-color: " + UIConstants.COLOR_BACKGROUND + ";");

        // 顶部标题栏
        HBox topBar = createTopBar();
        this.setTop(topBar);

        // 主体内容：左右分栏
        HBox mainContent = new HBox(20);
        mainContent.setAlignment(Pos.CENTER);
        mainContent.setPadding(new Insets(10));

        // 左侧：题目内容区
        VBox leftPanel = createLeftPanel();
        leftPanel.setMaxWidth(600);

        // 右侧：题目导航矩阵
        VBox rightPanel = createRightPanel();
        rightPanel.setMaxWidth(300);
        rightPanel.setMinWidth(280);

        HBox.setHgrow(leftPanel, Priority.ALWAYS);
        HBox.setHgrow(rightPanel, Priority.NEVER);
        mainContent.getChildren().addAll(leftPanel, rightPanel);
        this.setCenter(mainContent);

        // 底部按钮
        VBox bottomBarContainer = new VBox(10);
        bottomBarContainer.setAlignment(Pos.CENTER);
        bottomBarContainer.setPadding(new Insets(10));
        nextButton.setStyle(UIConstants.BUTTON_STYLE);
        submitButton.setStyle(UIConstants.BUTTON_STYLE + "-fx-background-color: " + UIConstants.COLOR_ERROR + ";");
        prevButton.setStyle(UIConstants.BUTTON_STYLE);
        nextButton.setPrefSize(UIConstants.BUTTON_WIDTH, UIConstants.BUTTON_HEIGHT);
        submitButton.setPrefSize(UIConstants.BUTTON_WIDTH, UIConstants.BUTTON_HEIGHT);
        prevButton.setPrefSize(UIConstants.BUTTON_WIDTH, UIConstants.BUTTON_HEIGHT);

        HBox buttonRow = new HBox(20);
        buttonRow.setAlignment(Pos.CENTER);
        buttonRow.getChildren().addAll(prevButton, nextButton, submitButton);

        bottomBarContainer.getChildren().add(buttonRow);

        this.setBottom(bottomBarContainer);

        // 初始化按钮状态
        updateButtonVisibility();
    }

    /**
     * 创建顶部标题栏
     */
    private HBox createTopBar() {
        HBox topBar = new HBox(20);
        topBar.setAlignment(Pos.CENTER_LEFT);
        topBar.setPadding(new Insets(10));
        topBar.setStyle("-fx-background-color: white; -fx-border-width: 0 0 1 0; -fx-border-color: #bdc3c7;");

        titleLabel.setFont(Font.font(UIConstants.FONT_FAMILY, FontWeight.BOLD, UIConstants.TITLE_FONT_SIZE));
        progressLabel.setStyle("-fx-font-size: " + UIConstants.HINT_FONT_SIZE + "px; -fx-text-fill: " + UIConstants.COLOR_HINT + ";");

        topBar.getChildren().addAll(titleLabel, progressLabel);
        return topBar;
    }

    /**
     * 创建左侧题目内容面板
     */
    private VBox createLeftPanel() {
        // 直接使用带样式的 VBox 作为内容容器
        VBox content = new VBox(UIConstants.DEFAULT_SPACING);
        content.setPadding(new Insets(20));
        content.setStyle(UIConstants.FORM_STYLE);
        content.setPrefWidth(550);
        content.setMinWidth(550);
        content.setMaxWidth(550);
        content.setPrefHeight(400);
        content.setMinHeight(400);
        content.setMaxHeight(400);

        questionLabel.setWrapText(true);
        questionLabel.setPrefWidth(500);
        questionLabel.setFont(Font.font(UIConstants.FONT_FAMILY, UIConstants.QUIZ_TITLE_FONT_SIZE));
        questionLabel.setStyle("-fx-font-size: " + UIConstants.QUIZ_TITLE_FONT_SIZE + "px; -fx-text-fill: " + UIConstants.COLOR_PRIMARY + ";");

        VBox optionsBox = new VBox(10);
        optionsBox.setAlignment(Pos.CENTER_LEFT);
        for (int i = 0; i < 4; i++) {
            options[i] = new RadioButton("选项 " + (char)('A' + i));
            options[i].setToggleGroup(optionGroup);
            options[i].setStyle("-fx-font-size: " + UIConstants.LABEL_FONT_SIZE + "px;");
            optionsBox.getChildren().add(options[i]);
        }

        content.getChildren().addAll(questionLabel, optionsBox);
        return content;
    }

    /**
     * 创建右侧题目导航矩阵面板
     */
    private VBox createRightPanel() {
        VBox rightPanel = new VBox(10);
        rightPanel.setAlignment(Pos.TOP_CENTER);
        rightPanel.setPadding(new Insets(20));
        rightPanel.setStyle(UIConstants.FORM_STYLE);

        Label navTitle = new Label("题目导航");
        navTitle.setFont(Font.font(UIConstants.FONT_FAMILY, FontWeight.BOLD, UIConstants.SUBTITLE_FONT_SIZE));
        navTitle.setAlignment(Pos.CENTER);

        // 初始化题目导航矩阵
        initQuestionNavGrid();

        rightPanel.getChildren().addAll(navTitle, questionNavGrid);
        return rightPanel;
    }

    /**
     * 初始化题目导航网格
     */
    private void initQuestionNavGrid() {
        questionNavGrid.getChildren().clear();
        questionNavGrid.setHgap(5);
        questionNavGrid.setVgap(5);
        questionNavGrid.setAlignment(Pos.CENTER);

        int cols = 5;
        int rows = (totalQuestions + cols - 1) / cols;

        for (int i = 0; i < totalQuestions; i++) {
            int row = i / cols;
            int col = i % cols;

            String text = String.valueOf(i + 1);
            Button btn = new Button(text);
            btn.setPrefSize(50, 40);
            btn.setFont(Font.font(UIConstants.FONT_FAMILY, UIConstants.LABEL_FONT_SIZE));
            btn.setStyle(getButtonStyleForStatus(i));

            final int index = i;
            btn.setOnAction(e -> goToQuestion(index));

            questionNavGrid.add(btn, col, row);
        }
    }

    /**
     * 根据题目状态返回按钮样式
     * @param index 题号（0-based）
     * @return CSS样式字符串
     */
    private String getButtonStyleForStatus(int index) {
        if (index == currentQuestionIndex) {
            // 当前题
            return "-fx-background-color: " + UIConstants.COLOR_ACCENT + "; -fx-text-fill: white; -fx-font-weight: bold;";
        } else if (quizService.isAnswered(index)) {
            // 已作答
            return "-fx-background-color: #2ecc71; -fx-text-fill: white;";
        } else {
            // 未作答
            return "-fx-background-color: #ecf0f1; -fx-text-fill: #2c3e50;";
        }
    }


    /**
     * 更新按钮可见性（最后一题显示“交卷”，否则显示“下一题”）
     */
    private void updateButtonVisibility() {
        if (currentQuestionIndex == totalQuestions - 1) {
            nextButton.setVisible(false);
            submitButton.setVisible(true);
        } else {
            nextButton.setVisible(true);
            submitButton.setVisible(false);
        }
    }

    /**
     * 跳转到指定题目
     * @param index 题号（0-based）
     */
    public void goToQuestion(int index) {
        currentQuestionIndex = index;
        quizService.goToQuestion(index);
        updateProgressLabel();
        updateQuestionNavButtons();
        updateButtonVisibility();
        loadQuestion(index);
    }

    /**
     * 更新进度标签
     */
    private void updateProgressLabel() {
        int answeredCount = quizService.getAnsweredCount();
        progressLabel.setText("完成 " + answeredCount + "/" + totalQuestions + " 题");
    }

    /**
     * 更新题目导航按钮样式
     */
    private void updateQuestionNavButtons() {
        for (Node node : questionNavGrid.getChildren()) {
            if (node instanceof Button) {
                Button btn = (Button) node;
                int index = Integer.parseInt(btn.getText()) - 1; // 转换为0-based
                btn.setStyle(getButtonStyleForStatus(index));
            }
        }
    }

    /**
     * 加载题目（从 QuizService 获取）
     * @param index 题号
     */
    private void loadQuestion(int index) {
        System.out.println("🔄 加载题目 " + index + ", options[0]=" + options[0]);
        if (options[0] == null) {
            System.err.println("⚠️ RadioButton 未初始化，跳过题目加载");
            return; // 防止 NPE
        }
        ChoiceQuestion question = quizService.getQuestion(index);
        if (question == null) return;

        // 显示题目
        questionLabel.setText("第 " + (index + 1) + " 题：\n" + question.getQuestionText());

        List<?> optionsList = question.getOptions();
        for (int i = 0; i < 4; i++) {
            Object option = optionsList.get(i);
            String optionText = option != null ? option.toString() : "未知";
            options[i].setText((char)('A' + i) + ". " + optionText);
        }

        Integer userAnswer = quizService.getUserAnswer(index);
        if (userAnswer != null && userAnswer >= 0 && userAnswer < 4) {
            optionGroup.selectToggle(options[userAnswer]);
        } else {
            optionGroup.selectToggle(null);
        }

        // ✅ 强制刷新 UI（可选，通常不需要）
        // Platform.runLater(() -> {
        //     this.requestLayout(); // 触发重新布局
        // });
    }

    // ========== Getter 方法 ==========
    public Label getProgressLabel() { return progressLabel; }
    public Label getQuestionLabel() { return questionLabel; }
    public RadioButton[] getOptions() { return options; }
    public ToggleGroup getOptionGroup() { return optionGroup; }
    public Button getNextButton() { return nextButton; }
    public Button getPrevButton() { return prevButton; }
    public Button getSubmitButton() { return submitButton; }

    // ========== 设置器方法 ==========
    public void setTotalQuestions(int total) {
        this.totalQuestions = total;
        initQuestionNavGrid(); // 重新初始化导航矩阵
        updateProgressLabel();
    }

    public void setCurrentQuestionIndex(int index) {
        this.currentQuestionIndex = index;
        updateQuestionNavButtons();
        updateButtonVisibility();
        loadQuestion(index);
    }
}