document.addEventListener('DOMContentLoaded', () => {
    // DOM Elements
    const chatBox = document.getElementById('chat-box');
    const textInput = document.getElementById('text-input');
    const sendBtn = document.getElementById('send-btn');
    const micBtn = document.getElementById('mic-btn');
    const loadingIndicator = document.getElementById('loading-indicator');
    const statusIndicator = document.getElementById('status-indicator');
    
    // Mode Buttons
    const modeTextBtn = document.getElementById('mode-text');
    const modeVoiceBtn = document.getElementById('mode-voice');
    const modeVideoBtn = document.getElementById('mode-video');

    // Voice Controls
    const voiceControls = document.getElementById('voice-controls');
    const continuousToggle = document.getElementById('continuous-toggle');
    const rateSlider = document.getElementById('rate');
    const pitchSlider = document.getElementById('pitch');

    // Video Elements
    const videoFeed = document.getElementById('video-feed');
    const canvas = document.getElementById('canvas');
    const imageModal = document.getElementById('image-capture-modal');
    const closeModalBtn = document.getElementById('close-modal-btn');

    // State Variables
    let sessionId = null; // Will be set before each new query
    let currentMode = 'text'; // 'text', 'voice', 'video'
    let isListening = false;
    let isContinuousMode = false;
    let videoStream = null;

    const API_BASE_URL = 'https://nitinbot001-medbot-backend.hf.space';

    // Speech Recognition (STT) Setup
    const SpeechRecognition = window.SpeechRecognition || window.webkitSpeechRecognition;
    let recognition;
    if (SpeechRecognition) {
        recognition = new SpeechRecognition();
        recognition.continuous = false;
        recognition.interimResults = false;
        recognition.lang = 'en-US'; // You can change this
    } else {
        micBtn.disabled = true;
        addMessageToUI('error', 'Speech Recognition is not supported in this browser.');
    }

    // Speech Synthesis (TTS) Setup
    const synth = window.speechSynthesis;

    // --- INITIALIZATION ---
    function initializeApp() {
        loadHistory();
        setupEventListeners();
        statusIndicator.textContent = '● Ready';
        statusIndicator.style.color = '#cccccc';
        addMessageToUI('ai', 'Hello! I am your MediBot Assistant. How can I help you today?');
    }

    async function startNewSession() {
        statusIndicator.textContent = '● Connecting...';
        statusIndicator.style.color = 'orange';
        try {
            const response = await fetch(`${API_BASE_URL}/start_session`, { method: 'POST' });
            if (!response.ok) throw new Error('Failed to start session');
            const data = await response.json();
            sessionId = data.session_id; // Set the session ID for the current transaction
            statusIndicator.textContent = '● Connected';
            statusIndicator.style.color = '#76ff03';
            console.log('New transaction session started:', sessionId);
            return true; // Indicate success
        } catch (error) {
            console.error('Session start error:', error);
            sessionId = null; // Ensure session ID is null on failure
            statusIndicator.textContent = '● Connection Failed';
            statusIndicator.style.color = '#ff4d4d';
            addMessageToUI('error', `Could not connect to the server. ${error.message}`);
            return false; // Indicate failure
        }
    }

    // --- EVENT LISTENERS ---
    function setupEventListeners() {
        sendBtn.addEventListener('click', handleTextInput);
        textInput.addEventListener('keydown', (e) => {
            if (e.key === 'Enter') handleTextInput();
        });

        // Mode Switching
        modeTextBtn.addEventListener('click', () => switchMode('text'));
        modeVoiceBtn.addEventListener('click', () => switchMode('voice'));
        modeVideoBtn.addEventListener('click', () => switchMode('video'));

        // Voice Controls
        micBtn.addEventListener('click', toggleListening);
        continuousToggle.addEventListener('change', (e) => {
            isContinuousMode = e.target.checked;
            if (recognition) {
                recognition.continuous = isContinuousMode;
            }
        });

        // STT Events
        if (recognition) {
            recognition.onstart = () => {
                isListening = true;
                micBtn.classList.add('listening');
                micBtn.innerHTML = '<i class="fas fa-stop"></i>';
            };
            recognition.onend = () => {
                isListening = false;
                micBtn.classList.remove('listening');
                micBtn.innerHTML = '<i class="fas fa-microphone"></i>';
                if (isContinuousMode && currentMode !== 'text') {
                    recognition.start(); // Keep listening in continuous mode
                }
            };
            recognition.onresult = (event) => {
                const transcript = event.results[event.results.length - 1][0].transcript.trim();
                textInput.value = transcript;
                processUserQuery(transcript);
            };
            recognition.onerror = (event) => {
                console.error('Speech recognition error:', event.error);
                addMessageToUI('error', `Speech recognition error: ${event.error}`);
            };
        }

        // Image Capture Modal
        closeModalBtn.addEventListener('click', () => {
            imageModal.classList.add('hidden');
            addMessageToUI('ai', 'Capturing image in 1 second...');
            setTimeout(captureAndSendImage, 1000);
        });
    }

    // --- CORE LOGIC ---
    function handleTextInput() {
        const query = textInput.value.trim();
        if (query) {
            processUserQuery(query);
            textInput.value = '';
        }
    }

    async function processUserQuery(query) {
        addMessageToUI('user', query);
        showLoading(true);

        // *** CHANGED LOGIC: Start a new session for every query ***
        const sessionStarted = await startNewSession();
        if (!sessionStarted) {
            showLoading(false);
            return; // Stop if session could not be created
        }

        try {
            const response = await fetch(`${API_BASE_URL}/process_query`, {
                method: 'POST',
                headers: { 'Content-Type': 'application/json' },
                body: JSON.stringify({ session_id: sessionId, query: query })
            });

            const data = await response.json();

            if (!response.ok) {
                throw new Error(data.error || 'API request failed');
            }

            if (data.status === 'image_required') {
                handleImageRequest(data.message);
            } else {
                const message = data.response?.response || data.data;
                handleApiResponse(message);
            }

        } catch (error) {
            console.error('Error processing query:', error);
            handleApiResponse(`Sorry, I encountered an error: ${error.message}`, true);
        } finally {
            showLoading(false);
        }
    }

    function handleApiResponse(message, isError = false) {
        const type = isError ? 'error' : 'ai';
        addMessageToUI(type, message);
        if (!isError && (currentMode === 'voice' || currentMode === 'video')) {
            speak(message);
        }
    }

    // --- UI & STATE MANAGEMENT ---
    function switchMode(newMode) {
        if (currentMode === newMode) return;
        
        if (currentMode === 'video') stopCamera();
        if (isListening && recognition) recognition.stop();

        currentMode = newMode;
        
        document.querySelectorAll('.mode-btn').forEach(btn => btn.classList.remove('active'));
        document.getElementById(`mode-${newMode}`).classList.add('active');

        if (newMode === 'text') {
            document.body.classList.remove('body-video-mode');
            voiceControls.classList.add('hidden');
            micBtn.classList.add('hidden');
            sendBtn.classList.remove('hidden');
            textInput.classList.remove('hidden');
            videoFeed.style.display = 'none';
        } else if (newMode === 'voice') {
            document.body.classList.remove('body-video-mode');
            voiceControls.classList.remove('hidden');
            micBtn.classList.remove('hidden');
            sendBtn.classList.add('hidden');
            textInput.classList.add('hidden');
            videoFeed.style.display = 'none';
        } else if (newMode === 'video') {
            document.body.classList.add('body-video-mode');
            voiceControls.classList.remove('hidden');
            micBtn.classList.remove('hidden');
            sendBtn.classList.add('hidden');
            textInput.classList.add('hidden');
            videoFeed.style.display = 'block';
            startCamera();
        }
    }

    function addMessageToUI(sender, text) {
        const messageDiv = document.createElement('div');
        messageDiv.classList.add('message', `${sender}-message`);
        messageDiv.textContent = text;
        chatBox.appendChild(messageDiv);
        chatBox.scrollTop = chatBox.scrollHeight;
        saveHistory();
    }
    
    function showLoading(show) {
        loadingIndicator.style.display = show ? 'flex' : 'none';
    }

    // --- VOICE & VIDEO ---
    function toggleListening() {
        if (!recognition) return;
        if (isListening) {
            recognition.stop();
        } else {
            recognition.start();
        }
    }

    function speak(text) {
        if (synth.speaking) {
            console.error('SpeechSynthesis is already speaking.');
            return;
        }
        if (text !== '') {
            const utterance = new SpeechSynthesisUtterance(text);
            const femaleVoice = synth.getVoices().find(voice => voice.name.includes('Female') || voice.gender === 'female');
            if(femaleVoice) utterance.voice = femaleVoice;
            utterance.pitch = pitchSlider.value;
            utterance.rate = rateSlider.value;
            synth.speak(utterance);
        }
    }

    async function startCamera() {
        try {
            videoStream = await navigator.mediaDevices.getUserMedia({ video: true, audio: false });
            videoFeed.srcObject = videoStream;
        } catch (err) {
            console.error("Error accessing camera: ", err);
            addMessageToUI('error', 'Could not access the camera. Please grant permission.');
            switchMode('voice');
        }
    }

    function stopCamera() {
        if (videoStream) {
            videoStream.getTracks().forEach(track => track.stop());
            videoFeed.srcObject = null;
            videoStream = null;
        }
    }
    
    function handleImageRequest(message) {
        addMessageToUI('ai', message);
        if (currentMode !== 'video') {
            addMessageToUI('ai', "Please switch to Video mode to provide an image.");
        } else {
            imageModal.classList.remove('hidden');
        }
    }

    async function captureAndSendImage() {
        if (!videoStream || !sessionId) {
            addMessageToUI('error', 'Cannot capture image. Video stream or session is not active.');
            return;
        };
        
        const videoTrack = videoStream.getVideoTracks()[0];
        const settings = videoTrack.getSettings();
        canvas.width = settings.width;
        canvas.height = settings.height;
        
        const context = canvas.getContext('2d');
        context.drawImage(videoFeed, 0, 0, canvas.width, canvas.height);

        canvas.toBlob(async (blob) => {
            const formData = new FormData();
            formData.append('session_id', sessionId);
            formData.append('photo', blob, 'capture.jpg');
            
            showLoading(true);
            try {
                const response = await fetch(`${API_BASE_URL}/process_with_image`, {
                    method: 'POST',
                    body: formData
                });
                
                const data = await response.json();
                if (!response.ok) throw new Error(data.message || 'Image processing failed');

                const message = data.response?.response || data.data;
                handleApiResponse(message);

            } catch (error) {
                console.error('Error sending image:', error);
                handleApiResponse(`Sorry, I couldn't process the image: ${error.message}`, true);
            } finally {
                showLoading(false);
            }
        }, 'image/jpeg');
    }

    // --- LOCAL STORAGE ---
    function saveHistory() {
        localStorage.setItem('medibotChatHistory', chatBox.innerHTML);
    }
    function loadHistory() {
        const history = localStorage.getItem('medibotChatHistory');
        if (history) {
            chatBox.innerHTML = history;
            chatBox.scrollTop = chatBox.scrollHeight;
        }
    }
    
    // --- START THE APP ---
    initializeApp();
});