// Amazon Multimodal Assistant - Main JavaScript
// Connected to Python Backend via FastAPI

class MultimodalAssistant {
    constructor() {
        this.searchHistory = []; // Local session history
        this.isSearching = false;
        this.currentUploadFile = null;
        
        // Configuration: Point to your local FastAPI server
        this.API_ENDPOINT = '/api/search'; 
        
        this.initializeEventListeners();
        this.initializeAnimations();
    }

    initializeEventListeners() {
        // Search functionality
        const searchBtn = document.getElementById('search-button');
        const searchText = document.getElementById('search-text');

        if (searchBtn) searchBtn.addEventListener('click', () => this.handleSearch());
        if (searchText) searchText.addEventListener('keypress', (e) => {
            if (e.key === 'Enter' && !e.shiftKey) { // Prevent default enter behavior in textarea usually needs shift
                e.preventDefault(); 
                this.handleSearch();
            }
        });

        // Image upload functionality
        this.initializeImageUpload();

        // Clear history
        const clearBtn = document.getElementById('clear-history');
        if (clearBtn) clearBtn.addEventListener('click', () => this.clearHistory());

        // Search mode radio buttons
        document.querySelectorAll('input[name="search-mode"]').forEach(radio => {
            radio.addEventListener('change', (e) => this.updateSearchMode(e.target.value));
        });
    }

    initializeImageUpload() {
        const uploadArea = document.getElementById('upload-area');
        const imageInput = document.getElementById('image-input');
        const removeButton = document.getElementById('remove-image');

        if (!uploadArea || !imageInput) return;

        // Click to upload
        uploadArea.addEventListener('click', (e) => {
            if (e.target !== removeButton && !e.target.closest('#remove-image')) {
                imageInput.click();
            }
        });

        // Drag and drop visuals
        uploadArea.addEventListener('dragover', (e) => {
            e.preventDefault();
            uploadArea.classList.add('dragover');
        });

        uploadArea.addEventListener('dragleave', () => {
            uploadArea.classList.remove('dragover');
        });

        uploadArea.addEventListener('drop', (e) => {
            e.preventDefault();
            uploadArea.classList.remove('dragover');
            if (e.dataTransfer.files.length > 0) {
                this.handleImageUpload(e.dataTransfer.files[0]);
            }
        });

        // File input change
        imageInput.addEventListener('change', (e) => {
            if (e.target.files.length > 0) {
                this.handleImageUpload(e.target.files[0]);
            }
        });

        // Remove image
        if (removeButton) {
            removeButton.addEventListener('click', (e) => {
                e.stopPropagation();
                this.removeImage();
            });
        }
    }

    handleImageUpload(file) {
        if (!file.type.startsWith('image/')) {
            this.showNotification('Please select a valid image file.', 'error');
            return;
        }
        
        // Save file object to send to API later
        this.currentUploadFile = file;

        const reader = new FileReader();
        reader.onload = (e) => {
            this.displayImagePreview(e.target.result);
            // Auto switch to multimodal if image uploaded
            const multiRadio = document.querySelector('input[name="search-mode"][value="multimodal"]');
            if(multiRadio) multiRadio.checked = true;
            this.showNotification('Image uploaded successfully', 'success');
        };
        reader.readAsDataURL(file);
    }

    displayImagePreview(src) {
        const uploadContent = document.getElementById('upload-content');
        const imagePreview = document.getElementById('image-preview');
        const previewImg = document.getElementById('preview-img');

        if (uploadContent) uploadContent.classList.add('hidden');
        if (imagePreview) imagePreview.classList.remove('hidden');
        if (previewImg) previewImg.src = src;
    }

    removeImage() {
        this.currentUploadFile = null;
        document.getElementById('upload-content').classList.remove('hidden');
        document.getElementById('image-preview').classList.add('hidden');
        document.getElementById('image-input').value = '';
    }

    async handleSearch() {
        if (this.isSearching) return;

        const textInput = document.getElementById('search-text');
        const textQuery = textInput ? textInput.value.trim() : "";
        
        // Get Search Mode
        const modeEl = document.querySelector('input[name="search-mode"]:checked');
        const searchMode = modeEl ? modeEl.value : "multimodal";
        
        const hasImage = !!this.currentUploadFile;

        // Validation
        if (!textQuery && !hasImage) {
            this.showNotification('Please enter text or upload an image.', 'warning');
            return;
        }

        this.isSearching = true;
        this.showLoadingState(true);

        // 1. Prepare Form Data for Backend
        const formData = new FormData();
        formData.append('query', textQuery);
        formData.append('mode', searchMode);
        
        // Pass history so LLM knows context
        const historyPayload = this.searchHistory.map(h => ({
            role: h.role, 
            content: h.content
        }));
        formData.append('history', JSON.stringify(historyPayload));

        if (this.currentUploadFile) {
            formData.append('image', this.currentUploadFile);
        }

        try {
            // 2. Call API
            const response = await fetch(this.API_ENDPOINT, {
                method: 'POST',
                body: formData
            });

            if (!response.ok) {
                throw new Error(`Server error: ${response.statusText}`);
            }

            const data = await response.json();

            // 3. Process Response & Update History
            this.addToHistory({
                role: 'user',
                content: textQuery || '[Image Query]',
                timestamp: new Date()
            });

            this.addToHistory({
                role: 'assistant',
                content: data.answer,
                timestamp: new Date()
            });

            // 4. Update UI
            this.displayQuery({
                text: textQuery,
                image: hasImage ? document.getElementById('preview-img').src : null,
                mode: data.retrieval_method
            });

            this.displayResults(data.products);
            this.displayAnswer(data.answer, data.retrieval_method);
            
            if (data.products && data.products.length > 0) {
                this.highlightEvidence(data.products[0]);
            } else {
                document.getElementById('evidence-card').classList.add('hidden');
            }

            // Optional: clear text input
            // if (textInput) textInput.value = '';

        } catch (error) {
            console.error('Search failed:', error);
            this.showNotification('Search failed: ' + error.message, 'error');
        } finally {
            this.isSearching = false;
            this.showLoadingState(false);
        }
    }

    displayQuery(query) {
        const queryCard = document.getElementById('query-card');
        const queryContent = document.getElementById('query-content');
        const queryImage = document.getElementById('query-image');
        const retrievalMethod = document.getElementById('retrieval-method');

        const methodLabels = {
            'text_only': 'Text Search',
            'image_only': 'Image Search', 
            'multimodal_fusion': 'Multimodal Fusion',
            'multimodal': 'Multimodal'
        };

        if (retrievalMethod) retrievalMethod.textContent = methodLabels[query.mode] || query.mode;
        
        if (queryContent) {
            queryContent.innerHTML = query.text ? `<strong>Text:</strong> "${query.text}"` : '<em>Image-only query</em>';
        }

        if (query.image && queryImage) {
            const img = queryImage.querySelector('img');
            if(img) img.src = query.image;
            queryImage.classList.remove('hidden');
        } else if (queryImage) {
            queryImage.classList.add('hidden');
        }

        if (queryCard) {
            queryCard.classList.remove('hidden');
            // Re-trigger animation if possible
            queryCard.classList.remove('fade-in');
            void queryCard.offsetWidth; // trigger reflow
            queryCard.classList.add('fade-in');
        }
    }

    displayAnswer(content, mode) {
        const answerCard = document.getElementById('answer-card');
        const answerContent = document.getElementById('answer-content');

        // Convert Markdown-like formatting to HTML
        let formattedContent = content
            .replace(/\n/g, '<br>') // Line breaks
            .replace(/\*\*(.*?)\*\*/g, '<strong>$1</strong>') // Bold text
            .replace(/\*(.*?)\*/g, '<em>$1</em>'); // Italic text

        // Convert Markdown image syntax to HTML img tags
        // Pattern: ![alt text](image_url)
        formattedContent = formattedContent.replace(
            /!\[(.*?)\]\((.*?)\)/g,
            (match, alt, url) => {
                // 如果是 images/ 开头的路径，转换为 /product_images/
                let correctedUrl = url;
                if (url.startsWith('images/')) {
                    correctedUrl = url.replace('images/', '/product_images/');
                }
                return `<br><img src="${correctedUrl}" alt="${alt}" class="max-w-md rounded-lg shadow-md my-4" onerror="this.src='https://via.placeholder.com/300?text=Image+Not+Found'" /><br>`;
            }
        );

        if (answerContent) answerContent.innerHTML = formattedContent;
        if (answerCard) answerCard.classList.remove('hidden');
    }

    highlightEvidence(product) {
        const evidenceCard = document.getElementById('evidence-card');
        const evidenceImage = document.getElementById('evidence-image');
        const evidenceName = document.getElementById('evidence-name');
        const evidenceCategory = document.getElementById('evidence-category');
        const evidenceSimilarity = document.getElementById('evidence-similarity');

        if (!evidenceCard) return;

        // Use backend URL or fallback
        const imgSrc = product.image || 'https://via.placeholder.com/150?text=No+Img';
        
        if (evidenceImage) {
            evidenceImage.src = imgSrc;
            evidenceImage.onerror = () => { evidenceImage.src = 'https://via.placeholder.com/150?text=Error'; };
        }

        if (evidenceName) evidenceName.textContent = product.name;
        if (evidenceCategory) evidenceCategory.textContent = product.category;
        if (evidenceSimilarity) evidenceSimilarity.textContent = `${Math.round(product.similarity * 100)}% match`;

        evidenceCard.classList.remove('hidden');
    }

    displayResults(products) {
        const resultsContainer = document.getElementById('results-container');
        const resultsCount = document.getElementById('results-count');

        if (resultsCount) resultsCount.textContent = `${products.length} items`;
        if (!resultsContainer) return;

        resultsContainer.innerHTML = '';

        if (!products || products.length === 0) {
            resultsContainer.innerHTML = '<div class="text-sm text-gray-500 text-center py-8">No products found.</div>';
            return;
        }

        // Restore the detailed card design you liked
        products.forEach((product, index) => {
            const card = document.createElement('div');
            // Using your original classes
            card.className = 'product-card bg-white rounded-lg p-3 border border-gray-200 mb-3 hover:shadow-md transition-shadow';
            
            const similarityPercentage = Math.round(product.similarity * 100);
            const imgSrc = product.image || 'https://via.placeholder.com/64?text=No+Img';
            
            card.innerHTML = `
                <div class="flex items-start space-x-3">
                    <div class="flex-shrink-0 w-12 h-12 bg-white rounded-lg overflow-hidden border border-gray-100 flex items-center justify-center">
                        <img src="${imgSrc}" alt="${product.name}" 
                             class="w-full h-full object-contain"
                             onerror="this.src='https://via.placeholder.com/64?text=Err'">
                    </div>
                    <div class="flex-1 min-w-0">
                        <h4 class="text-sm font-semibold text-gray-800 truncate" title="${product.name}">${index + 1}. ${product.name}</h4>
                        <p class="text-xs text-gray-600 mb-1">${product.category}</p>
                        <div class="flex items-center justify-between">
                            <span class="text-xs text-gray-500">Score: ${(product.similarity).toFixed(3)}</span>
                            <div class="flex items-center space-x-2">
                                <div class="w-16 h-1.5 bg-gray-100 rounded-full overflow-hidden">
                                    <div class="similarity-bar h-full bg-orange-500" style="width: ${similarityPercentage}%"></div>
                                </div>
                                <span class="text-xs font-bold text-gray-700">${similarityPercentage}%</span>
                            </div>
                        </div>
                    </div>
                </div>
            `;
            resultsContainer.appendChild(card);
        });
    }

    addToHistory(item) {
        this.searchHistory.push(item);
        this.updateHistoryDisplay();
    }

    updateHistoryDisplay() {
        const container = document.getElementById('history-container');
        if (!container) return;

        if (this.searchHistory.length === 0) {
            container.innerHTML = '<div class="text-sm text-gray-500 text-center py-8">Start by entering a search query above</div>';
            return;
        }
        
        // Show last 6 items, reversed
        const displayItems = this.searchHistory.slice(-6).reverse();

        // Restore your original history styling
        container.innerHTML = displayItems.map(item => `
            <div class="bg-gray-50 rounded-lg p-3 border border-gray-200 mb-2">
                <div class="flex items-center justify-between mb-1">
                    <span class="text-xs font-bold ${item.role === 'user' ? 'text-blue-600' : 'text-orange-600'}">
                        ${item.role === 'user' ? 'YOU' : 'AI'}
                    </span>
                    <span class="text-xs text-gray-400">
                        ${item.timestamp.toLocaleTimeString([], {hour: '2-digit', minute:'2-digit'})}
                    </span>
                </div>
                <div class="text-sm text-gray-700 line-clamp-2">
                    ${item.content}
                </div>
            </div>
        `).join('');
    }

    clearHistory() {
        this.searchHistory = [];
        this.updateHistoryDisplay();
        this.showNotification('History cleared', 'success');
    }

    showLoadingState(isLoading) {
        const loadingState = document.getElementById('loading-state');
        const resultsContainer = document.getElementById('results-container');
        const btnText = document.getElementById('btn-text');
        
        // Button Spinner logic
        if (loadingState) {
            if (isLoading) {
                loadingState.classList.remove('hidden');
                if (btnText) btnText.textContent = 'Searching...';
            } else {
                loadingState.classList.add('hidden');
                if (btnText) btnText.textContent = 'Search Products';
            }
        }
        
        // Optional: Skeleton loading in results area (restoring your logic)
        if (resultsContainer && isLoading) {
            resultsContainer.innerHTML = `
                <div class="space-y-4 animate-pulse">
                    <div class="h-20 bg-gray-100 rounded-lg"></div>
                    <div class="h-20 bg-gray-100 rounded-lg"></div>
                    <div class="h-20 bg-gray-100 rounded-lg"></div>
                </div>
            `;
        }
    }

    showNotification(message, type = 'info') {
        // Remove existing notifications
        const existing = document.querySelectorAll('.fixed.top-4.right-4');
        existing.forEach(el => el.remove());

        const notification = document.createElement('div');
        const bgColor = type === 'error' ? 'bg-red-500' : (type === 'success' ? 'bg-green-500' : 'bg-blue-500');
        
        notification.className = `fixed top-4 right-4 z-50 px-6 py-3 rounded-lg shadow-lg text-white font-medium fade-in ${bgColor}`;
        notification.textContent = message;
        
        document.body.appendChild(notification);
        
        setTimeout(() => {
            notification.style.opacity = '0';
            notification.style.transform = 'translateY(-20px)';
            notification.style.transition = 'all 0.5s ease';
            setTimeout(() => notification.remove(), 500);
        }, 3000);
    }
    
    // UI Helpers
    updateSearchMode(mode) {
        // Just logic to highlight or log change if needed
        // The radio button state is handled natively by HTML
    }
    
    initializeAnimations() {
        // Restoring Anime.js hover effects if library is loaded
        if (typeof anime !== 'undefined') {
            document.querySelectorAll('.hover-lift').forEach(element => {
                element.addEventListener('mouseenter', () => {
                    anime({
                        targets: element,
                        translateY: -2,
                        boxShadow: '0 10px 25px -5px rgba(0, 0, 0, 0.1)',
                        duration: 200,
                        easing: 'easeOutQuad'
                    });
                });

                element.addEventListener('mouseleave', () => {
                    anime({
                        targets: element,
                        translateY: 0,
                        boxShadow: 'none', // or original shadow
                        duration: 200,
                        easing: 'easeOutQuad'
                    });
                });
            });
        }
    }
}

document.addEventListener('DOMContentLoaded', () => {
    new MultimodalAssistant();
});