// Study Mode Module
class StudyMode extends BaseModule {
    constructor() {
        super();
        this.showingAnswer = false;
        this.navigator = null;
        this.init();
    }

    init() {
        this.setupEventListeners();
        this.loadQuestions();
    }

    setupEventListeners() {
        // Filter controls
        document.getElementById('apply-filters')?.addEventListener('click', () => {
            this.loadQuestions();
        });

        document.getElementById('reset-filters')?.addEventListener('click', () => {
            document.getElementById('start-question').value = 1;
            document.getElementById('end-question').value = 200;
            this.loadQuestions();
        });

        // Navigation controls
        document.getElementById('prev-btn')?.addEventListener('click', () => {
            this.previousQuestion();
        });

        document.getElementById('next-btn')?.addEventListener('click', () => {
            this.nextQuestion();
        });

        // Answer controls
        document.getElementById('show-answer')?.addEventListener('click', () => {
            this.showAnswer();
        });

        document.getElementById('hide-answer')?.addEventListener('click', () => {
            this.hideAnswer();
        });

        // Keyboard navigation
        document.addEventListener('keydown', (e) => {
            this.handleKeyboard(e);
        });
    }

    async loadQuestions() {
        this.showLoading();
        BaseModule.hide('study-content');
        BaseModule.hide('no-questions');

        const start = document.getElementById('start-question').value;
        const end = document.getElementById('end-question').value;

        try {
            const data = await this.fetchQuestions({
                mode: 'range',
                start: start,
                end: end
            });

            this.questions = data;
            this.currentIndex = 0;

            if (this.questions.length === 0) {
                this.hideLoading();
                BaseModule.show('no-questions');
                return;
            }

            document.getElementById('total-questions').textContent = this.questions.length;

            // Initialize navigator
            this.initializeNavigator(start, end);

            this.displayQuestion();
            this.updateProgress('study-progress');

            this.hideLoading();
            BaseModule.show('study-content');

        } catch (error) {
            this.hideLoading();
            console.error('Error in loadQuestions:', error);
        }
    }

    initializeNavigator(start, end) {
        if (!this.navigator) {
            this.navigator = new QuestionNavigator('question-navigator', {
                onQuestionSelect: (index) => {
                    this.currentIndex = index;
                    this.displayQuestion();
                    this.hideAnswer();
                },
                storagePrefix: `study_${start}_${end}`
            });
        }

        this.navigator.setQuestions(this.questions);
    }

    displayQuestion() {
        if (this.questions.length === 0) return;

        const question = this.questions[this.currentIndex];

        let html = this.createQuestionHTML(question, this.currentIndex, this.questions.length);
        html += this.createOptionsHTML(question.options, question.correct);

        document.getElementById('question-container').innerHTML = html;

        // Animate options
        this.animateOptions();

        this.updateNavigation('prev-btn', 'next-btn', 'current-question');
        this.updateProgress('study-progress');

        if (this.navigator) {
            this.navigator.setCurrentIndex(this.currentIndex);
        }
    }

    animateOptions() {
        const options = document.querySelectorAll('.option-btn');
        options.forEach((option, index) => {
            option.style.opacity = '0';
            option.style.transform = 'translateY(20px)';
            setTimeout(() => {
                option.style.transition = 'all 0.3s ease';
                option.style.opacity = '1';
                option.style.transform = 'translateY(0)';
            }, index * 100);
        });
    }

    showAnswer() {
        const correctOption = document.querySelector('.option-btn[data-correct="true"]');
        if (correctOption) {
            correctOption.classList.add('correct', 'correct-option');
            correctOption.style.background = 'rgba(39, 174, 96, 0.3)';
            correctOption.style.borderColor = '#27ae60';
            correctOption.style.color = '#ffffff';
            correctOption.style.fontWeight = 'bold';

            const indicator = correctOption.querySelector('.answer-indicator');
            if (indicator) {
                indicator.style.display = 'inline';
            }
        }

        // Dim incorrect options
        const incorrectOptions = document.querySelectorAll('.option-btn[data-correct="false"]');
        incorrectOptions.forEach(option => {
            option.classList.add('text-muted');
            option.style.opacity = '0.6';
        });

        BaseModule.hide('show-answer');
        BaseModule.show('hide-answer');
        this.showingAnswer = true;
    }

    hideAnswer() {
        const allOptions = document.querySelectorAll('.option-btn');
        allOptions.forEach(option => {
            option.classList.remove('correct', 'correct-option', 'text-muted');
            option.style.background = '';
            option.style.borderColor = '';
            option.style.color = '';
            option.style.fontWeight = '';
            option.style.opacity = '';
        });

        const indicators = document.querySelectorAll('.answer-indicator');
        indicators.forEach(indicator => {
            indicator.style.display = 'none';
        });

        BaseModule.show('show-answer');
        BaseModule.hide('hide-answer');
        this.showingAnswer = false;
    }

    previousQuestion() {
        if (this.currentIndex > 0) {
            this.currentIndex--;
            this.displayQuestion();
            this.hideAnswer();
        }
    }

    nextQuestion() {
        if (this.currentIndex < this.questions.length - 1) {
            this.currentIndex++;
            this.displayQuestion();
            this.hideAnswer();
        }
    }

    handleKeyboard(e) {
        if (e.key === 'ArrowLeft' && this.currentIndex > 0) {
            this.previousQuestion();
        } else if (e.key === 'ArrowRight' && this.currentIndex < this.questions.length - 1) {
            this.nextQuestion();
        } else if (e.key === ' ') {
            e.preventDefault();
            if (this.showingAnswer) {
                this.hideAnswer();
            } else {
                this.showAnswer();
            }
        }
    }
}

// Auto-initialize when DOM is ready
document.addEventListener('DOMContentLoaded', function() {
    if (document.getElementById('study-content')) {
        window.studyMode = new StudyMode();
    }
});

// Export for global use
window.StudyMode = StudyMode;