/**
 * Accessibility Mode UI - Touch Keyboard & STT Display
 */

class AccessibilityUI {
    constructor() {
        this.keyboardBuffer = '';
        this.displayData = { history: [], keyboard_buffer: '' };
        this.wsConnected = false;

        this.initializeElements();
        this.attachEventListeners();
        this.startPolling();
    }

    initializeElements() {
        this.keyboardBufferEl = document.getElementById('keyboard-buffer');
        this.transcriptDisplay = document.getElementById('transcript-display');
        this.transcriptHistoryEl = null;
        this.sttStatusEl = document.getElementById('stt-status');
        this.ttsStatusEl = document.getElementById('tts-status');
        this.modeIndicatorEl = document.getElementById('mode-indicator');

        // Keyboard buttons
        this.keyButtons = document.querySelectorAll('.key[data-char]');
        this.backspaceBtn = document.getElementById('backspace-btn');
        this.spaceBtn = document.getElementById('space-btn');
        this.clearBtn = document.getElementById('clear-btn');
        this.sendBtn = document.getElementById('send-btn');
    }

    attachEventListeners() {
        // Character keys
        this.keyButtons.forEach(btn => {
            btn.addEventListener('click', () => this.inputCharacter(btn.dataset.char));
            btn.addEventListener('touch start', (e) => e.preventDefault());
        });

        // Special keys
        this.backspaceBtn.addEventListener('click', () => this.backspace());
        this.spaceBtn.addEventListener('click', () => this.inputCharacter(' '));
        this.clearBtn.addEventListener('click', () => this.clearBuffer());
        this.sendBtn.addEventListener('click', () => this.sendInput());

        // Physical keyboard support
        document.addEventListener('keydown', (e) => this.handlePhysicalKey(e));
    }

    inputCharacter(char) {
        this.keyboardBuffer += char.toUpperCase();
        this.updateDisplay();
        this.sendToROS('', false); // Update display on ROS
    }

    backspace() {
        this.keyboardBuffer = this.keyboardBuffer.slice(0, -1);
        this.updateDisplay();
        this.sendToROS('', false);
    }

    clearBuffer() {
        this.keyboardBuffer = '';
        this.updateDisplay();
        this.sendToROS('[CLEAR]', false);
    }

    sendInput() {
        if (this.keyboardBuffer.trim()) {
            this.sendToROS('[SEND]', true);
            this.keyboardBuffer = '';
            this.updateDisplay();
        }
    }

    handlePhysicalKey(e) {
        if (e.target !== document.body) return;

        const char = e.key.toUpperCase();

        if (e.key === 'Backspace') {
            e.preventDefault();
            this.backspace();
        } else if (e.key === 'Enter') {
            e.preventDefault();
            this.sendInput();
        } else if (char.match(/^[A-Z0-9 .,!?]$/)) {
            this.inputCharacter(char);
        }
    }

    updateDisplay() {
        this.keyboardBufferEl.textContent = this.keyboardBuffer || '(empty)';
        this.renderTranscriptHistory();
    }

    renderTranscriptHistory() {
        if (!this.displayData.history) return;

        let html = '';
        this.displayData.history.forEach(entry => {
            const cls = entry.type === 'stt' ? 'transcript-stt' : 'transcript-keyboard';
            const icon = entry.type === 'stt' ? '🎤' : '⌨️';
            const text = entry.text || '';
            html += `<div class="transcript-entry ${cls}">${icon} ${this.escapeHtml(text)}</div>`;
        });

        if (!html) {
            html = '<div class="placeholder">Waiting for speech...</div>';
        }

        this.transcriptDisplay.innerHTML = html;
        // Auto-scroll to bottom
        this.transcriptDisplay.scrollTop = this.transcriptDisplay.scrollHeight;
    }

    sendToROS(command, isFinal) {
        // This will be called when we have a WebSocket connection to the ROS2 bridge
        const data = {
            command: command,
            buffer: this.keyboardBuffer,
            timestamp: Date.now(),
            final: isFinal
        };

        console.log('Sending to ROS:', data);

        // Send via fetch API to UI server
        fetch('/api/keyboard', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify(data)
        }).catch(err => console.error('ROS send error:', err));
    }

    startPolling() {
        // Poll for display updates from ROS2
        setInterval(() => this.pollDisplayUpdate(), 500);
    }

    pollDisplayUpdate() {
        fetch('/api/display')
            .then(res => res.json())
            .then(data => {
                if (data && data.history) {
                    this.displayData = data;
                    this.renderTranscriptHistory();
                    this.updateStatusIndicators();
                }
            })
            .catch(err => console.error('Display poll error:', err));
    }

    updateStatusIndicators() {
        // Update STT/TTS status based on display data
        if (this.displayData.history && this.displayData.history.length > 0) {
            const lastEntry = this.displayData.history[this.displayData.history.length - 1];
            if (lastEntry.type === 'stt') {
                this.sttStatusEl.textContent = lastEntry.final ? 'Complete' : 'Listening...';
            }
        }
    }

    escapeHtml(text) {
        const div = document.createElement('div');
        div.textContent = text;
        return div.innerHTML;
    }
}

// Initialize when DOM is ready
document.addEventListener('DOMContentLoaded', () => {
    window.accessibilityUI = new AccessibilityUI();
});