// Global application state
let currentResults = [];
let currentMode = 'single';

// Initialization
document.addEventListener('DOMContentLoaded', function() {
    initializeApp();
});

function initializeApp() {
    setupTabHandlers();
    setupKeyboardHandlers();
    updateHeaderStats('Ready');
}

// Tab management
function setupTabHandlers() {
    document.querySelectorAll('.tab-button').forEach(button => {
        button.addEventListener('click', function() {
            const mode = this.dataset.mode;
            switchMode(mode);
        });
    });
}

function switchMode(mode) {
    currentMode = mode;
    
    // Update tabs
    document.querySelectorAll('.tab-button').forEach(btn => {
        btn.classList.remove('active');
    });
    document.querySelector(`[data-mode="${mode}"]`).classList.add('active');
    
    // Update forms
    document.querySelectorAll('.search-form').forEach(form => {
        form.classList.remove('active');
    });
    document.getElementById(`${mode}-form`).classList.add('active');
    
    // Reset results
    hideResults();
}

// Show version field only when the input looks like a spec (ETSI or 3GPP)
const ETSI_SPEC_RE = /^\d{3} \d{3}/;
const ETSI_TDOC_RE = /^(?:SET|SCP|SETTEC|SETREQ|SCPTEC|SCPREQ)\(\d+\)\d+/i;
const GPP_SPEC_RE  = /^\d{2}\.\d{3}/;

function toggleVersionField() {
    const docId = document.getElementById('doc-id').value.trim();
    const versionGroup = document.getElementById('single-version-group');
    const formatGroup  = document.getElementById('single-format-group');
    const isSpec     = ETSI_SPEC_RE.test(docId) || GPP_SPEC_RE.test(docId);
    const isEtsiSpec = ETSI_SPEC_RE.test(docId);
    versionGroup.style.display = isSpec     ? 'block' : 'none';
    formatGroup.style.display  = isEtsiSpec ? 'block' : 'none';
    if (!isSpec)     document.getElementById('doc-version').value = '';
    if (!isEtsiSpec) document.getElementById('doc-format').value  = 'pdf';
}

// Keyboard shortcuts management
function setupKeyboardHandlers() {
    document.getElementById('doc-id').addEventListener('keypress', function(e) {
        if (e.key === 'Enter') searchSingle();
    });
    
    document.getElementById('keywords').addEventListener('keypress', function(e) {
        if (e.key === 'Enter') searchKeyword();
    });
    
    document.getElementById('bm25-keywords').addEventListener('keypress', function(e) {
        if (e.key === 'Enter') searchBM25();
    });
}

// Search functions
async function searchSingle() {
    const docId = document.getElementById('doc-id').value.trim();

    if (!docId) {
        showError('Please enter a document ID');
        return;
    }

    const format = document.getElementById('doc-format').value || 'pdf';
    const isDocx = ETSI_SPEC_RE.test(docId) && format === 'docx';

    if (isDocx) {
        downloadDocx(docId);
        return;
    }

    showLoading();
    updateHeaderStats('Searching...');

    try {
        const version = document.getElementById('doc-version').value.trim() || null;
        const body = { doc_id: docId };
        if (version) body.version = version;

        const response = await fetch(`/find/single`, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
            },
            body: JSON.stringify(body)
        });

        const data = await response.json();

        if (response.ok) {
            displaySingleResult(data);
            updateHeaderStats(`Found in ${data.search_time.toFixed(3)}s`);
        } else {
            showError(data.detail);
            updateHeaderStats('Error');
        }
    } catch (error) {
        showError('Error connecting to server');
        updateHeaderStats('Error');
        console.error('Error:', error);
    } finally {
        hideLoading();
    }
}

async function downloadDocx(docId) {
    showLoading();
    updateHeaderStats('Downloading DOCX...');

    try {
        const version = document.getElementById('doc-version').value.trim() || null;
        const body = { doc_id: docId };
        if (version) body.version = version;

        const response = await fetch('/find/docx', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify(body)
        });

        if (response.ok) {
            const blob = await response.blob();
            const disposition = response.headers.get('Content-Disposition') || '';
            const fnMatch = disposition.match(/filename="?([^";\n]+)"?/);
            const filename = fnMatch ? fnMatch[1] : `${docId.replace(/ /g, '_')}.docx`;
            const url = URL.createObjectURL(blob);
            const a = document.createElement('a');
            a.href = url;
            a.download = filename;
            document.body.appendChild(a);
            a.click();
            document.body.removeChild(a);
            URL.revokeObjectURL(url);
            updateHeaderStats('DOCX downloaded');
        } else {
            const data = await response.json();
            showError(data.detail);
            updateHeaderStats('Error');
        }
    } catch (error) {
        showError('Error connecting to server');
        updateHeaderStats('Error');
        console.error('Error:', error);
    } finally {
        hideLoading();
    }
}

async function searchBatch() {
    const batchText = document.getElementById('batch-ids').value.trim();
    
    if (!batchText) {
        showError('Please enter at least one document ID');
        return;
    }
    
    const docIds = batchText.split('\n')
        .map(id => id.trim())
        .filter(id => id !== '');
    
    if (docIds.length === 0) {
        showError('Please enter at least one valid document ID');
        return;
    }
    
    showLoading();
    updateHeaderStats('Searching...');
    
    try {
        const version = document.getElementById('batch-version').value.trim() || null;
        const body = { doc_ids: docIds };
        if (version) body.version = version;

        const response = await fetch(`/find/batch`, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
            },
            body: JSON.stringify(body)
        });
        
        const data = await response.json();
        
        if (response.ok) {
            displayBatchResults(data);
            updateHeaderStats(`${Object.keys(data.results).length} found, ${data.missing.length} missing - ${data.search_time.toFixed(3)}s`);
        } else {
            showError(data.detail);
            updateHeaderStats('Error');
        }
    } catch (error) {
        showError('Error connecting to server');
        updateHeaderStats('Error');
        console.error('Error:', error);
    } finally {
        hideLoading();
    }
}

async function searchKeyword() {
    const keywords = document.getElementById('keywords').value.trim();
    const searchMode = document.getElementById('search-mode-filter').value;
    
    if (!keywords && searchMode === 'deep') {
        showError('Please enter at least one keyword in deep search mode');
        return;
    }
    
    showLoading();
    updateHeaderStats('Searching...');
    
    try {
        const body = {
            keywords: keywords,
            search_mode: searchMode,
            case_sensitive: document.getElementById('case-sensitive-filter').checked,
            source: document.getElementById('source-filter').value,
            mode: document.getElementById('mode-filter').value
        };
        
        const specType = document.getElementById('spec-type-filter').value;
        if (specType) {
            body.spec_type = specType;
        }
        
        const response = await fetch(`/search`, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
            },
            body: JSON.stringify(body)
        });
        
        const data = await response.json();
        
        if (response.ok) {
            displaySearchResults(data);
            updateHeaderStats(`${data.results.length} result(s) - ${data.search_time.toFixed(3)}s`);
        } else {
            showError(data.detail);
            updateHeaderStats('Error');
        }
    } catch (error) {
        showError('Error connecting to server');
        updateHeaderStats('Error');
        console.error('Error:', error);
    } finally {
        hideLoading();
    }
}

async function searchBM25() {
    const keywords = document.getElementById('bm25-keywords').value.trim();
    
    if (!keywords) {
        showError('Please enter a search query');
        return;
    }
    
    showLoading();
    updateHeaderStats('Searching...');
    
    try {
        const body = {
            keywords: keywords,
            source: document.getElementById('bm25-source-filter').value,
            threshold: parseInt(document.getElementById('threshold').value) || 60
        };
        
        const specType = document.getElementById('bm25-spec-type-filter').value;
        if (specType) {
            body.spec_type = specType;
        }
        
        const response = await fetch(`/search/bm25`, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
            },
            body: JSON.stringify(body)
        });
        
        const data = await response.json();
        
        if (response.ok) {
            displaySearchResults(data);
            updateHeaderStats(`${data.results.length} result(s) - ${data.search_time.toFixed(3)}s`);
        } else {
            showError(data.detail);
            updateHeaderStats('Error');
        }
    } catch (error) {
        showError('Error connecting to server');
        updateHeaderStats('Error');
        console.error('Error:', error);
    } finally {
        hideLoading();
    }
}

// Results display functions
function displaySingleResult(data) {
    const resultsContent = document.getElementById('results-content');
    const isEtsiTdoc = ETSI_TDOC_RE.test(data.doc_id);

    const urlBlock = isEtsiTdoc
        ? `<div class="result-detail">
               <strong>URL:</strong> <span class="result-url-text">${data.url}</span>
               <button class="btn btn-primary download-btn" onclick="downloadTdoc('${data.doc_id}')">Download</button>
           </div>`
        : `<div class="result-detail result-url">
               <strong>URL:</strong> <a href="${data.url}" target="_blank">${data.url}</a>
           </div>`;

    resultsContent.innerHTML = `
        <div class="result-item">
            <div class="result-header">
                <div class="result-id">${data.doc_id}</div>
                <div class="result-status status-found">Found</div>
            </div>
            <div class="result-details">
                ${data.version ? `<div class="result-detail"><strong>Version:</strong> ${data.version}</div>` : ''}
                ${data.scope ? `<div class="result-detail"><strong>Scope:</strong> ${data.scope}</div>` : ''}
                ${urlBlock}
            </div>
        </div>
    `;

    showResults();
}

async function downloadTdoc(docId) {
    showLoading();
    updateHeaderStats('Downloading...');
    try {
        const response = await fetch('/find/tdoc/download', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ doc_id: docId })
        });
        if (response.ok) {
            const blob = await response.blob();
            const disposition = response.headers.get('Content-Disposition') || '';
            const fnMatch = disposition.match(/filename="?([^";\n]+)"?/);
            const filename = fnMatch ? fnMatch[1] : `${docId}.docx`;
            const url = URL.createObjectURL(blob);
            const a = document.createElement('a');
            a.href = url;
            a.download = filename;
            document.body.appendChild(a);
            a.click();
            document.body.removeChild(a);
            URL.revokeObjectURL(url);
            updateHeaderStats('Downloaded');
        } else {
            const data = await response.json();
            showError(data.detail);
            updateHeaderStats('Error');
        }
    } catch (error) {
        showError('Error connecting to server');
        updateHeaderStats('Error');
        console.error('Error:', error);
    } finally {
        hideLoading();
    }
}

function displayBatchResults(data) {
    const resultsContent = document.getElementById('results-content');
    let html = '';
    
    // Found results
    Object.entries(data.results).forEach(([docId, url]) => {
        html += `
            <div class="result-item">
                <div class="result-header">
                    <div class="result-id">${docId}</div>
                    <div class="result-status status-found">Found</div>
                </div>
                <div class="result-details">
                    <div class="result-detail result-url">
                        <strong>URL:</strong> <a href="${url}" target="_blank">${url}</a>
                    </div>
                </div>
            </div>
        `;
    });
    
    // Missing documents
    data.missing.forEach(docId => {
        html += `
            <div class="result-item">
                <div class="result-header">
                    <div class="result-id">${docId}</div>
                    <div class="result-status status-missing">Not Found</div>
                </div>
                <div class="result-details">
                    <div class="result-detail">Document not found or not indexed</div>
                </div>
            </div>
        `;
    });
    
    resultsContent.innerHTML = html;
    showResults();
}

function displaySearchResults(data) {
    const resultsContent = document.getElementById('results-content');
    currentResults = data.results;
    
    let html = '';
    
    data.results.forEach((spec, index) => {
        const hasContent = spec.contains && Object.keys(spec.contains).length > 0;
        
        html += `
            <div class="result-item">
                <div class="result-header">
                    <div class="result-id">${spec.id}</div>
                    <div class="result-status status-found">${spec.type || 'Specification'}</div>
                </div>
                <div class="result-details">
                    <div class="result-detail"><strong>Title:</strong> ${spec.title}</div>
                    ${spec.version ? `<div class="result-detail"><strong>Version:</strong> ${spec.version}</div>` : ''}
                    ${spec.working_group ? `<div class="result-detail"><strong>Working Group:</strong> ${spec.working_group}</div>` : ''}
                    ${spec.type ? `<div class="result-detail"><strong>Type:</strong> ${spec.type}</div>` : ''}
                    ${spec.scope ? `<div class="result-detail"><strong>Scope:</strong> ${spec.scope}</div>` : ''}
                    ${spec.url ? `<div class="result-detail result-url"><strong>URL:</strong> <a href="${spec.url}" target="_blank">${spec.url}</a></div>` : ''}
                    ${hasContent ? `<button class="view-content-btn" onclick="viewContent(${index})">View Content</button>` : ''}
                </div>
            </div>
        `;
    });
    
    resultsContent.innerHTML = html;
    showResults();
}

// Content display functions
function viewContent(index) {
    const spec = currentResults[index];
    
    if (!spec.contains) return;
    
    document.getElementById('content-title').textContent = `${spec.id} - ${spec.title}`;
    
    const contentSections = document.getElementById('content-sections');
    let html = '';
    
    Object.entries(spec.contains).forEach(([sectionTitle, content]) => {
        html += `
            <div class="content-section">
                <h3>${sectionTitle}</h3>
                <p>${content}</p>
                <button class="copy-section-btn" onclick="copyText('${content.replace(/'/g, "\\'")}')">
                    Copy this section
                </button>
            </div>
        `;
    });
    
    contentSections.innerHTML = html;
    showContentPage();
}

function closeContentPage() {
    hideContentPage();
}

function copyAllContent() {
    const sections = document.querySelectorAll('.content-section p');
    const allText = Array.from(sections).map(p => p.textContent).join('\n\n');
    copyText(allText);
}

function copyText(text) {
    navigator.clipboard.writeText(text).then(() => {
        showSuccess('Text copied to clipboard');
    }).catch(() => {
        showError('Error copying text');
    });
}

// Interface utilities
function showLoading() {
    document.getElementById('loading-container').style.display = 'flex';
    hideResults();
    hideError();
}

function hideLoading() {
    document.getElementById('loading-container').style.display = 'none';
}

function showResults() {
    document.getElementById('results-container').style.display = 'block';
    hideError();
}

function hideResults() {
    document.getElementById('results-container').style.display = 'none';
}

function showContentPage() {
    document.getElementById('content-page').classList.add('active');
}

function hideContentPage() {
    document.getElementById('content-page').classList.remove('active');
}

function showError(message) {
    hideError();
    const errorDiv = document.createElement('div');
    errorDiv.className = 'error-message';
    errorDiv.textContent = message;
    document.querySelector('.search-container').appendChild(errorDiv);
    
    setTimeout(() => {
        hideError();
    }, 5000);
}

function showSuccess(message) {
    hideError();
    const successDiv = document.createElement('div');
    successDiv.className = 'success-message';
    successDiv.textContent = message;
    document.querySelector('.search-container').appendChild(successDiv);
    
    setTimeout(() => {
        hideError();
    }, 3000);
}

function hideError() {
    const existingMessages = document.querySelectorAll('.error-message, .success-message');
    existingMessages.forEach(msg => msg.remove());
}

function updateHeaderStats(text) {
    document.getElementById('header-stats').innerHTML = `<span class="stat-item">${text}</span>`;
}