// Global state management
const state = {
    isLoading: false,
    currentPdfUrl: null
};

// Add state management for the current paper
let currentPaperState = {
    pdfUrl: null,
    title: null
};

// Add state management for search results
let searchState = {
    lastResults: null,
    lastQuery: null
};

// Utility Functions
function getCsrfToken() {
    return document.querySelector('meta[name="csrf-token"]').getAttribute('content');
}

function showLoading() {
    const overlay = document.getElementById('loadingOverlay');
    overlay.classList.remove('hidden');
    state.isLoading = true;
}

function hideLoading() {
    const overlay = document.getElementById('loadingOverlay');
    overlay.classList.add('hidden');
    state.isLoading = false;
}

// Search Functionality
async function performSearch() {
    const searchQuery = document.getElementById('searchInput').value.trim();
    const sortBy = document.getElementById('sortBy').value;
    const maxResults = parseInt(document.getElementById('maxResults').value);

    if (!searchQuery) {
        alert('Please enter a search term');
        return;
    }

    // Show loading overlay
    document.getElementById('loadingOverlay').classList.remove('hidden');

    try {
        const response = await fetch('/search', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
                'X-CSRFToken': getCsrfToken()
            },
            body: JSON.stringify({
                paper_name: searchQuery,
                sort_by: sortBy,
                max_results: maxResults
            })
        });

        const data = await response.json();
        
        // Save the results to the state
        searchState.lastResults = data;
        searchState.lastQuery = searchQuery;

        // Get results section and clear it
        const resultsSection = document.getElementById('resultsSection');
        resultsSection.innerHTML = '';

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

        // Show results section
        showResults();

        if (data.length === 0) {
            resultsSection.innerHTML = `
                <div class="no-results">
                    <p>No papers found matching your search.</p>
                </div>`;
            return;
        }

        // Create results container
        const resultsGrid = document.createElement('div');
        resultsGrid.className = 'results-grid';

        // Add each paper to the grid
        data.forEach(paper => {
            const paperCard = document.createElement('div');
            paperCard.className = 'paper-card';
            paperCard.innerHTML = `
                <h3 class="paper-title">${escapeHtml(paper.title)}</h3>
                <p class="paper-authors">Authors: ${escapeHtml(paper.authors)}</p>
                <p class="paper-category">Category: ${escapeHtml(paper.category)}</p>
                <p class="paper-date">Published: ${escapeHtml(paper.published)}</p>
                <p class="paper-abstract">${escapeHtml(paper.abstract.substring(0, 200))}...</p>
                <div class="paper-actions">
                    <a href="${paper.pdf_link}" target="_blank" class="action-button pdf-button">PDF</a>
                    <a href="${paper.arxiv_link}" target="_blank" class="action-button arxiv-button">ARXIV</a>
                    <button onclick="analyzePaper('${paper.pdf_link}', '${escapeHtml(paper.title)}')" class="action-button analyze">Analyze</button>
                </div>
            `;
            resultsGrid.appendChild(paperCard);
        });

        resultsSection.appendChild(resultsGrid);

    } catch (error) {
        console.error('Search error:', error);
        document.getElementById('resultsSection').innerHTML = `
            <div class="error-message">
                <p>Failed to search papers: ${error.message}</p>
            </div>`;
    } finally {
        // Hide loading overlay
        document.getElementById('loadingOverlay').classList.add('hidden');
    }
}

// Helper function to escape HTML and prevent XSS
function escapeHtml(unsafe) {
    return unsafe
        .replace(/&/g, "&amp;")
        .replace(/</g, "&lt;")
        .replace(/>/g, "&gt;")
        .replace(/"/g, "&quot;")
        .replace(/'/g, "&#039;");
}

// Display Functions
function displayResults(results) {
    const resultsSection = document.getElementById('resultsSection');
    resultsSection.innerHTML = '';

    const resultsGrid = document.createElement('div');
    resultsGrid.className = 'results-grid';

    results.forEach((paper, index) => {
        // Create paper card
        const paperCard = document.createElement('div');
        paperCard.className = 'paper-card';
        
        // Build the card HTML - removed save button
        paperCard.innerHTML = `
            <div class="paper-date">${paper.published}</div>
            <h2 class="paper-title">${paper.title}</h2>
            <div class="paper-author">${paper.authors}</div>
            <p class="paper-abstract">${paper.abstract}</p>
            <div class="paper-actions">
                <div class="action-row">
                    <button class="action-link view-pdf">VIEW PDF</button>
                    <button class="action-link arxiv">ARXIV</button>
                    <button class="action-button analyze">ANALYZE</button>
                </div>
            </div>
        `;

        // Add the paper card to the grid
        resultsGrid.appendChild(paperCard);

        // Add click handlers for remaining buttons
        const viewPdfButton = paperCard.querySelector('.view-pdf');
        viewPdfButton.addEventListener('click', () => window.open(paper.pdf_link, '_blank'));

        const arxivButton = paperCard.querySelector('.arxiv');
        arxivButton.addEventListener('click', () => window.open(paper.arxiv_link, '_blank'));

        const analyzeButton = paperCard.querySelector('.analyze');
        analyzeButton.addEventListener('click', () => analyzePaper(paper.pdf_link, paper.title));
    });

    resultsSection.appendChild(resultsGrid);
}

// Analysis Functions
async function analyzePaper(pdfUrl, paperTitle) {
    // Update current paper state
    currentPaperState.pdfUrl = pdfUrl;
    currentPaperState.title = paperTitle;

    // Show loading overlay
    showLoading();
    
    try {
        const response = await fetch('/perform-rag', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
                'X-CSRFToken': getCsrfToken()
            },
            body: JSON.stringify({
                pdf_url: pdfUrl,
                paper_title: paperTitle
            })
        });

        const data = await response.json();

        if (data.error) {
            throw new Error(data.error);
        }

        // Show results section
        const resultsSection = document.getElementById('resultsSection');
        resultsSection.innerHTML = `
            <div class="analysis-container">
                <div class="analysis-header">
                    <button onclick="backToSearchResults()" class="back-button">
                        <span>←</span> Back to Results
                    </button>
                    <h2 class="current-paper-title">${paperTitle}</h2>
                </div>
                
                <div class="analysis-tabs">
                    <button id="paperAnalysisTab" 
                            class="tab-button active" 
                            onclick="switchPaperTab('analysis')">
                        Paper Analysis
                    </button>
                    <button id="chatWithPaperTab" 
                            class="tab-button" 
                            onclick="switchPaperTab('chat')">
                        Chat with Paper
                    </button>
                </div>

                <div id="analysisContent" class="tab-content active">
                    <div class="analysis-section">
                        <h3>Research Paper Analysis</h3>
                        <div class="analysis-content">
                            ${marked.parse(data.analysis.executive_summary)}
                        </div>
                    </div>
                </div>

                <div id="chatContent" class="tab-content">
                    <div class="chat-container">
                        <div class="quick-questions">
                            <button class="quick-question-btn" onclick="handleQuickQuestion('What are the main findings?')">
                                What are the main findings?
                            </button>
                            <button class="quick-question-btn" onclick="handleQuickQuestion('Explain the methodology')">
                                Explain the methodology
                            </button>
                            <button class="quick-question-btn" onclick="handleQuickQuestion('Key contributions?')">
                                Key contributions?
                            </button>
                            <button class="quick-question-btn" onclick="handleQuickQuestion('Future research directions?')">
                                Future research directions?
                            </button>
                        </div>
                        <div class="chat-messages" id="chatMessages">
                            <div class="message-wrapper">
                                <div class="message-avatar ai-avatar">AI</div>
                                <div class="message ai-message">
                                    Hello! I'm here to help you understand this research paper better. 
                                    Feel free to ask any questions about the paper's content, methodology, 
                                    findings, or implications.
                                </div>
                            </div>
                        </div>
                        <div class="chat-input-area">
                            <input type="text" 
                                   class="chat-input" 
                                   placeholder="Ask a question about the paper..." 
                                   id="chatInput">
                            <button class="chat-send-button" onclick="sendMessage()">
                                <span>Send</span>
                                <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
                                    <path d="M22 2L11 13M22 2l-7 20-4-9-9-4 20-7z"/>
                                </svg>
                            </button>
                        </div>
                    </div>
                </div>
            </div>
        `;

    } catch (error) {
        console.error('Analysis error:', error);
        document.getElementById('resultsSection').innerHTML = `
            <div class="error-message">
                Failed to analyze paper: ${error.message}
            </div>
        `;
    } finally {
        hideLoading();
    }
}

// Function to switch between paper analysis and chat tabs
function switchPaperTab(tab) {
    const analysisBtnTab = document.getElementById('paperAnalysisTab');
    const chatBtnTab = document.getElementById('chatWithPaperTab');
    const analysisContent = document.getElementById('analysisContent');
    const chatContent = document.getElementById('chatContent');

    if (tab === 'analysis') {
        analysisBtnTab.classList.add('active');
        chatBtnTab.classList.remove('active');
        analysisContent.classList.add('active');
        chatContent.classList.remove('active');
    } else {
        chatBtnTab.classList.add('active');
        analysisBtnTab.classList.remove('active');
        chatContent.classList.add('active');
        analysisContent.classList.remove('active');
    }
}

// Function to handle chat messages
async function sendMessage() {
    const chatInput = document.getElementById('chatInput');
    const question = chatInput.value.trim();
    
    if (!question || !currentPaperState.pdfUrl) return;

    const chatMessages = document.getElementById('chatMessages');
    
    // Add user message
    addMessage(question, true);

    // Add AI thinking message with loading animation
    const thinkingMessageId = 'ai-thinking-' + Date.now();
    addMessage(`${thinkingMessageId} AI is thinking...`, false);

    chatInput.value = '';
    chatMessages.scrollTop = chatMessages.scrollHeight;

    try {
        const response = await fetch('/chat-with-paper', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
                'X-CSRFToken': getCsrfToken()
            },
            body: JSON.stringify({
                pdf_url: currentPaperState.pdfUrl,
                question: question
            })
        });

        const data = await response.json();

        if (data.error) {
            throw new Error(data.error);
        }

        // Remove thinking message
        const thinkingMessage = document.getElementById(thinkingMessageId);
        if (thinkingMessage) {
            thinkingMessage.remove();
        }

        // Add AI response
        addMessage(data.response, false);

        chatMessages.scrollTop = chatMessages.scrollHeight;

    } catch (error) {
        console.error('Chat error:', error);
        // Remove thinking message
        const thinkingMessage = document.getElementById(thinkingMessageId);
        if (thinkingMessage) {
            thinkingMessage.remove();
        }

        addMessage(`Error: ${error.message}`, false);
    }
}

// Navigation Functions
function showHome() {
    hideAllSections();
    document.getElementById('homeSection').classList.add('active');
    document.getElementById('backButton').style.display = 'none';
}

function showResults() {
    hideAllSections();
    document.getElementById('resultsSection').classList.add('active');
    document.getElementById('currentSection').textContent = 'Search Results';
    document.getElementById('backButton').style.display = 'block';
}

function hideAllSections() {
    const sections = ['homeSection', 'historySection', 'savedSection', 'resultsSection'];
    sections.forEach(section => {
        document.getElementById(section).classList.remove('active');
    });
}

function goBack() {
    showHome();
}

// Load search history
function loadSearchHistory() {
    const historyGrid = document.getElementById('searchHistory');
    try {
        const history = JSON.parse(localStorage.getItem('searchHistory') || '[]');
        
        if (history.length === 0) {
            historyGrid.innerHTML = '<p class="no-history">No search history yet</p>';
            return;
        }

        historyGrid.innerHTML = '';
        history.forEach(item => {
            const historyCard = document.createElement('div');
            historyCard.className = 'history-card';
            historyCard.innerHTML = `
                <h3>${item.query}</h3>
                <p class="timestamp">${new Date(item.timestamp).toLocaleDateString()}</p>
                <button onclick="repeatSearch('${item.query}')" class="action-button">Search Again</button>
            `;
            historyGrid.appendChild(historyCard);
        });
    } catch (error) {
        console.error('Error loading history:', error);
        historyGrid.innerHTML = '<p class="error-message">Error loading history</p>';
    }
}

// Add notification system
function showNotification(message, type = 'info') {
    const notification = document.createElement('div');
    notification.className = `notification ${type}`;
    notification.textContent = message;
    document.body.appendChild(notification);
    
    setTimeout(() => {
        notification.classList.add('show');
        setTimeout(() => {
            notification.classList.remove('show');
            setTimeout(() => notification.remove(), 300);
        }, 2000);
    }, 100);
}

// Add history functionality
function saveToHistory(query, results) {
    try {
        const history = JSON.parse(localStorage.getItem('searchHistory') || '[]');
        history.unshift({
            query,
            timestamp: new Date().toISOString(),
            results: results.slice(0, 3) // Save only first 3 results to save space
        });
        // Keep only last 10 searches
        localStorage.setItem('searchHistory', JSON.stringify(history.slice(0, 10)));
    } catch (error) {
        console.error('Error saving to history:', error);
    }
}

// Add function to repeat search from history
function repeatSearch(query) {
    const searchInput = document.getElementById('searchInput');
    searchInput.value = query;
    showHome();
    performSearch();
}

// Add tab switching functionality
function switchTab(tabName) {
    // Update tab buttons
    document.querySelectorAll('.tab-button').forEach(button => {
        button.classList.remove('active');
        if (button.textContent.toLowerCase().includes(tabName)) {
            button.classList.add('active');
        }
    });

    // Update tab content
    document.querySelectorAll('.tab-content').forEach(content => {
        content.classList.remove('active');
    });
    document.getElementById(`${tabName}Tab`).classList.add('active');
}

// Add function to return to search results
function showSearchResults() {
    if (lastSearchResults) {
        displayResults(lastSearchResults);
        // Update navigation state
        document.getElementById('currentSection').textContent = 'Search Results';
    } else {
        showHome();
    }
}

// Add function to handle back to search
function backToSearchResults() {
    if (searchState.lastResults) {
        const resultsSection = document.getElementById('resultsSection');
        resultsSection.innerHTML = '';

        // Create results container
        const resultsGrid = document.createElement('div');
        resultsGrid.className = 'results-grid';

        // Recreate the results from the saved state
        searchState.lastResults.forEach(paper => {
            const paperCard = document.createElement('div');
            paperCard.className = 'paper-card';
            paperCard.innerHTML = `
                <h3 class="paper-title">${escapeHtml(paper.title)}</h3>
                <p class="paper-authors">Authors: ${escapeHtml(paper.authors)}</p>
                <p class="paper-category">Category: ${escapeHtml(paper.category)}</p>
                <p class="paper-date">Published: ${escapeHtml(paper.published)}</p>
                <p class="paper-abstract">${escapeHtml(paper.abstract.substring(0, 200))}...</p>
                <div class="paper-actions">
                    <a href="${paper.pdf_link}" target="_blank" class="action-button pdf-button">PDF</a>
                    <a href="${paper.arxiv_link}" target="_blank" class="action-button arxiv-button">ARXIV</a>
                    <button onclick="analyzePaper('${paper.pdf_link}', '${escapeHtml(paper.title)}')" class="action-button analyze">Analyze</button>
                </div>
            `;
            resultsGrid.appendChild(paperCard);
        });

        resultsSection.appendChild(resultsGrid);
    } else {
        // If no previous results, redirect to home
        showHome();
    }
}

// Add function to handle search history
function updateSearchHistory(searchTerm) {
    try {
        let searches = JSON.parse(localStorage.getItem('recentSearches') || '[]');
        
        // Add new search with timestamp
        searches.unshift({
            term: searchTerm,
            date: new Date().toISOString()
        });
        
        // Keep only the most recent 9 searches
        searches = searches.slice(0, 9);
        
        localStorage.setItem('recentSearches', JSON.stringify(searches));
        displaySearchHistory();
    } catch (error) {
        console.error('Error updating search history:', error);
    }
}

// Add function to display search history
function displaySearchHistory() {
    const historyContainer = document.getElementById('searchHistory');
    if (!historyContainer) return;

    try {
        const searches = JSON.parse(localStorage.getItem('recentSearches') || '[]');
        
        historyContainer.innerHTML = `
            <h2 class="history-title">Recent Searches</h2>
            <div class="search-history-grid">
                ${searches.map(search => `
                    <div class="history-item">
                        <h3 class="search-term">${search.term}</h3>
                        <div class="search-date">
                            ${new Date(search.date).toLocaleDateString('en-GB')}
                        </div>
                        <button 
                            onclick="searchAgain('${search.term}')" 
                            class="search-again-btn">
                            SEARCH AGAIN
                        </button>
                    </div>
                `).join('')}
            </div>
        `;
    } catch (error) {
        console.error('Error displaying search history:', error);
    }
}

// Add function to handle search again
function searchAgain(term) {
    document.getElementById('searchInput').value = term;
    handleSearch(term);
}

// Update the search container HTML in your JavaScript
function initializeSearchInterface() {
    const searchSection = document.querySelector('.search-section');
    if (searchSection) {
        searchSection.innerHTML = `
            <div class="search-container">
                <input 
                    type="text" 
                    id="searchInput" 
                    class="search-input" 
                    placeholder="Enter research paper title"
                    autocomplete="off"
                >
                <select id="sortBy" class="filter-select">
                    <option value="relevance">Sort by Relevance</option>
                    <option value="lastUpdated">Sort by Last Updated</option>
                </select>
                <select id="maxResults" class="filter-select">
                    <option value="10">10 results</option>
                    <option value="25">25 results</option>
                    <option value="50">50 results</option>
                </select>
                <button id="searchButton" class="search-button">
                    SCAN
                </button>
            </div>
        `;

        // Add event listeners
        const searchInput = document.getElementById('searchInput');
        const searchButton = document.getElementById('searchButton');

        searchInput.addEventListener('keypress', (e) => {
            if (e.key === 'Enter') {
                performSearch();
            }
        });

        searchButton.addEventListener('click', performSearch);
    }
}

function createChatInterface() {
    return `
        <div class="chat-container">
            <div class="quick-questions">
                <button class="quick-question-btn" onclick="handleQuickQuestion('What are the main findings?')">
                    What are the main findings?
                </button>
                <button class="quick-question-btn" onclick="handleQuickQuestion('Explain the methodology')">
                    Explain the methodology
                </button>
                <button class="quick-question-btn" onclick="handleQuickQuestion('Key contributions?')">
                    Key contributions?
                </button>
                <button class="quick-question-btn" onclick="handleQuickQuestion('Future research directions?')">
                    Future research directions?
                </button>
            </div>
            <div class="chat-messages" id="chatMessages">
                <div class="message-wrapper">
                    <div class="message-avatar ai-avatar">AI</div>
                    <div class="message ai-message">
                        Hello! I'm here to help you understand this research paper better. 
                        Feel free to ask any questions about the paper's content, methodology, 
                        findings, or implications.
                    </div>
                </div>
            </div>
            <div class="chat-input-area">
                <input type="text" 
                       class="chat-input" 
                       placeholder="Ask a question about the paper..." 
                       id="chatInput">
                <button class="chat-send-button" onclick="sendMessage()">
                    <span>Send</span>
                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
                        <path d="M22 2L11 13M22 2l-7 20-4-9-9-4 20-7z"/>
                    </svg>
                </button>
            </div>
        </div>
    `;
}

function addMessage(message, isUser = false) {
    const chatMessages = document.getElementById('chatMessages');
    const messageWrapper = document.createElement('div');
    messageWrapper.className = 'message-wrapper';
    
    const avatar = document.createElement('div');
    avatar.className = `message-avatar ${isUser ? 'user-avatar' : 'ai-avatar'}`;
    avatar.textContent = isUser ? 'You' : 'AI';
    
    const messageDiv = document.createElement('div');
    messageDiv.className = `message ${isUser ? 'user-message' : 'ai-message'}`;
    
    // Convert markdown to HTML if it's an AI message
    if (!isUser) {
        messageDiv.innerHTML = marked.parse(message);
    } else {
        messageDiv.textContent = message;
    }
    
    messageWrapper.appendChild(avatar);
    messageWrapper.appendChild(messageDiv);
    chatMessages.appendChild(messageWrapper);
    
    // Scroll to bottom
    chatMessages.scrollTop = chatMessages.scrollHeight;
}

// Add this new function to handle quick questions
async function handleQuickQuestion(question) {
    // Add user's question to chat
    addMessage(question, true);
    
    // Show thinking indicator
    const thinkingDiv = addThinkingMessage();
    
    try {
        const response = await fetch('/chat-with-paper', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
                'X-CSRFToken': getCsrfToken()
            },
            body: JSON.stringify({
                pdf_url: currentPaperState.pdfUrl,
                question: question
            })
        });

        const data = await response.json();
        
        // Remove thinking indicator
        thinkingDiv.remove();

        if (data.error) {
            addMessage(`Error: ${data.error}`, false);
            return;
        }

        // Add AI's response to chat
        addMessage(data.response, false);

    } catch (error) {
        // Remove thinking indicator
        thinkingDiv.remove();
        addMessage(`Error: ${error.message}`, false);
    }
}

// Event Listeners
document.addEventListener('DOMContentLoaded', () => {
    // Navigation initialization
    showHome();
    
    initializeSearchInterface();
    
    // Search button click
    const searchButton = document.getElementById('searchButton');
    searchButton.addEventListener('click', performSearch);
    
    // Search input enter key
    const searchInput = document.getElementById('searchInput');
    searchInput.addEventListener('keypress', (e) => {
        if (e.key === 'Enter') {
            performSearch();
        }
    });
});

function addThinkingMessage() {
    const chatMessages = document.getElementById('chatMessages');
    const thinkingDiv = document.createElement('div');
    thinkingDiv.className = 'ai-thinking';
    thinkingDiv.innerHTML = `
        <div class="ai-thinking-dots">
            <div class="ai-thinking-dot"></div>
            <div class="ai-thinking-dot"></div>
            <div class="ai-thinking-dot"></div>
        </div>
    `;
    chatMessages.appendChild(thinkingDiv);
    chatMessages.scrollTop = chatMessages.scrollHeight;
    return thinkingDiv;
}