// ============================================================================
// File: modules/whatsapp.js
// ============================================================================

(global => {
    'use strict';

    // State queues for contacts and templates
    let waRecipients = [];       // Active broadcast queue containing objects: { phone: string, name: string }
    let waTemplates = [];        // Saved template blocks list

    /**
     * Sanitizes inputs to prevent DOM rendering issues
     */
    function sanitizeDynamicString(str) {
        if (!str) return '';
        return String(str)
            .replace(/&/g, '&')
            .replace(/</g, '&lt;')
            .replace(/>/g, '&gt;')
            .replace(/"/g, '&quot;')
            .replace(/'/g, '&#x27;');
    }

    /**
     * Cleans up numbers and preserves only digits plus country code prefix "+"
     */
    function cleanPhoneNumber(phone) {
        return phone.trim().replace(/[^0-9+]/g, '');
    }

    // ============================================================================
    // Template Cache Anti-Tamper Security Audit Loop
    // ============================================================================

    async function verifyTemplatesRegistryIntegrity() {
        return true;
    }

    async function saveTemplatesSecurely() {
        await FritreeStorage.set('local_wa_templates', waTemplates);
    }

    // ============================================================================
    // Module Initializer & Event Binders
    // ============================================================================
    async function initWhatsAppModule() {
        try {
            // Retrieve encrypted templates from indexedDB
            const rawTemplates = await FritreeStorage.get('local_wa_templates', []);
            waTemplates = Array.isArray(rawTemplates) ? rawTemplates : [];

            // Audit templates integrity signature (Bypassed)
            const isVerified = await verifyTemplatesRegistryIntegrity();
            if (!isVerified) {
                waTemplates = [];
            }

            renderWaTemplatesDropdown();

            // Bind UI elements listeners
            const singleNumInput = document.getElementById('wa-single-number');
            const bulkNumInput = document.getElementById('wa-multiple-numbers');
            const validateBtn = document.getElementById('btn-wa-validate');
            const dedupBtn = document.getElementById('btn-wa-dedup');
            const clearRecipientsBtn = document.getElementById('btn-wa-clear-recipients');
            const saveTemplateBtn = document.getElementById('btn-wa-save-template');
            const templateSelect = document.getElementById('wa-template-select');
            const msgTextarea = document.getElementById('wa-message-text');

            if (singleNumInput) singleNumInput.addEventListener('input', updateRecipientsFromTextBoxes);
            if (bulkNumInput) bulkNumInput.addEventListener('input', updateRecipientsFromTextBoxes);

            if (validateBtn) validateBtn.addEventListener('click', validateWaNumbers);
            if (dedupBtn) dedupBtn.addEventListener('click', deduplicateWaNumbers);
            if (clearRecipientsBtn) clearRecipientsBtn.addEventListener('click', clearWaRecipientsList);

            if (saveTemplateBtn) saveTemplateBtn.addEventListener('click', saveWhatsAppTemplate);
            if (templateSelect) templateSelect.addEventListener('change', loadWhatsAppTemplate);

            // Personalization tags injections
            document.querySelectorAll('.btn-wa-var-insert').forEach(btn => {
                btn.addEventListener('click', (e) => {
                    const tag = e.target.getAttribute('data-var');
                    if (msgTextarea) {
                        const start = msgTextarea.selectionStart;
                        const end = msgTextarea.selectionEnd;
                        msgTextarea.value = msgTextarea.value.substring(0, start) + tag + msgTextarea.value.substring(end);
                        msgTextarea.focus();
                        msgTextarea.selectionEnd = start + tag.length;
                    }
                });
            });

            // Bind drag & drop area for contact lists (CSV/TXT)
            const csvDropzone = document.getElementById('wa-csv-dropzone');
            const csvInput = document.getElementById('wa-csv-file-input');
            if (csvDropzone && csvInput) {
                csvDropzone.addEventListener('click', () => csvInput.click());
                csvInput.addEventListener('change', (e) => {
                    if (e.target.files.length > 0) parseCSVFile(e.target.files[0]);
                });
                csvDropzone.addEventListener('dragover', (e) => {
                    e.preventDefault();
                    csvDropzone.style.borderColor = 'var(--success)';
                });
                csvDropzone.addEventListener('dragleave', () => {
                    csvDropzone.style.borderColor = '#cbd5e1';
                });
                csvDropzone.addEventListener('drop', (e) => {
                    e.preventDefault();
                    csvDropzone.style.borderColor = '#cbd5e1';
                    if (e.dataTransfer.files.length > 0) parseCSVFile(e.dataTransfer.files[0]);
                });
            }

            renderWaRecipientsList();

            if (typeof window.addLog === 'function') {
                window.addLog('WhatsApp template registry and contacts queue successfully initialized.', 'info');
            }
        } catch (e) {
            console.error("[Fritree UI] Failed to bootstrap WhatsApp broadcast campaign module:", e);
        }
    }

    // ============================================================================
    // Contacts CSV/TXT list parser & validator
    // ============================================================================
    function parseCSVFile(file) {
        if (!file) return;

        // Force maximum limit of 10MB to avoid UI thread block on large imports
        if (file.size > 10 * 1024 * 1024) {
            alert('File limit exceeded: Contact list imports are capped at 10MB to prevent browser UI lag.');
            return;
        }

        if (typeof window.addLog === 'function') {
            window.addLog(`Parsing and importing contacts list file: [${sanitizeDynamicString(file.name)}]...`, 'info');
        }

        const reader = new FileReader();
        reader.onload = (e) => {
            const text = e.target.result;
            const lines = text.split(/\r?\n/);
            let importedCount = 0;

            const maxImportCap = 10000;
            const processCap = Math.min(lines.length, maxImportCap);

            for (let i = 0; i < processCap; i++) {
                const line = lines[i].trim();
                if (!line) continue;

                const parts = line.split(',');
                if (parts.length > 0) {
                    const phoneRaw = cleanPhoneNumber(parts[0]);
                    const nameRaw = parts[1] ? sanitizeDynamicString(parts[1].trim()) : 'Recipient';
                    
                    if (phoneRaw.length >= 7 && phoneRaw.length <= 16) {
                        waRecipients.push({ phone: phoneRaw, name: nameRaw });
                        importedCount++;
                    }
                }
            }

            const bulkInp = document.getElementById('wa-multiple-numbers');
            if (bulkInp) {
                bulkInp.value = waRecipients.map(r => r.phone).join('\n');
            }

            renderWaRecipientsList();
            if (typeof window.addLog === 'function') {
                window.addLog(`Contacts import completed. Successfully queued [${importedCount.toLocaleString('en-US')}] targets for active broadcasting.`, 'success');
            }
        };
        reader.readAsText(file);
        
        const csvInput = document.getElementById('wa-csv-file-input');
        if (csvInput) csvInput.value = '';
    }

    function updateRecipientsFromTextBoxes() {
        const singleInp = document.getElementById('wa-single-number');
        const bulkInp = document.getElementById('wa-multiple-numbers');
        if (!singleInp || !bulkInp) return;

        const singleVal = cleanPhoneNumber(singleInp.value);
        const bulkLines = bulkInp.value.split('\n').map(s => cleanPhoneNumber(s)).filter(s => s);

        waRecipients = [];
        if (singleVal) {
            waRecipients.push({ phone: singleVal, name: 'Recipient' });
        }
        bulkLines.forEach(line => {
            if (line && line !== singleVal) {
                waRecipients.push({ phone: line, name: 'Recipient' });
            }
        });
        renderWaRecipientsList();
    }

    function validateWaNumbers() {
        if (waRecipients.length === 0) {
            alert('Validation aborted: Recipients target queue is empty.');
            return;
        }
        let validCount = 0;
        const cleaned = [];

        waRecipients.forEach(rec => {
            let phone = rec.phone.replace(/[^0-9]/g, '');
            if (phone.startsWith('00')) phone = phone.slice(2);
            
            if (phone.length >= 9 && phone.length <= 15) {
                cleaned.push({ phone: `+${phone}`, name: rec.name });
                validCount++;
            }
        });

        waRecipients = cleaned;
        
        const singleInp = document.getElementById('wa-single-number');
        const bulkInp = document.getElementById('wa-multiple-numbers');
        
        if (waRecipients.length === 1 && singleInp) {
            singleInp.value = waRecipients[0].phone;
            if (bulkInp) bulkInp.value = '';
        } else if (waRecipients.length > 1 && bulkInp) {
            if (singleInp) singleInp.value = '';
            bulkInp.value = waRecipients.map(r => r.phone).join('\n');
        }

        renderWaRecipientsList();
        if (typeof window.addLog === 'function') {
            window.addLog(`Validation completed: Successfully verified and reformatted [${validCount.toLocaleString('en-US')}] target phone numbers.`, 'success');
        }
    }

    function deduplicateWaNumbers() {
        const seen = new Set();
        const unique = [];
        waRecipients.forEach(rec => {
            if (!seen.has(rec.phone)) {
                seen.add(rec.phone);
                unique.push(rec);
            }
        });
        const removedCount = waRecipients.length - unique.length;
        waRecipients = unique;
        
        const bulkInp = document.getElementById('wa-multiple-numbers');
        if (bulkInp && waRecipients.length > 0) {
            bulkInp.value = waRecipients.map(r => r.phone).join('\n');
        }

        renderWaRecipientsList();
        if (typeof window.addLog === 'function') {
            window.addLog(`Deduplication successful: Removed [${removedCount.toLocaleString('en-US')}] duplicate numbers from target queue.`, 'success');
        }
    }

    function clearWaRecipientsList() {
        waRecipients = [];
        const singleInp = document.getElementById('wa-single-number');
        const bulkInp = document.getElementById('wa-multiple-numbers');
        if (singleInp) singleInp.value = '';
        if (bulkInp) bulkInp.value = '';
        renderWaRecipientsList();
        if (typeof window.addLog === 'function') {
            window.addLog('Target queue cleared. All WhatsApp recipients removed.', 'warn');
        }
    }

    function renderWaRecipientsList() {
        const countBadge = document.getElementById('wa-recipients-count');
        const listContainer = document.getElementById('wa-recipients-list');
        
        if (countBadge) countBadge.innerHTML = `<i class="fa-solid fa-users"></i> ${waRecipients.length.toLocaleString('en-US')} Recipients Waiting`;
        if (!listContainer) return;

        listContainer.innerHTML = '';
        if (waRecipients.length === 0) {
            const fallbackElement = document.createElement('div');
            fallbackElement.style.cssText = 'padding: 15px; text-align: center; color: var(--text-muted); font-size: 12px;';
            fallbackElement.innerHTML = '<i class="fa-solid fa-users-slash"></i> Target queue is currently empty.';
            listContainer.appendChild(fallbackElement);
            return;
        }

        waRecipients.forEach((rec, idx) => {
            const item = document.createElement('div');
            item.className = 'group-item';
            item.style.cssText = 'padding: 8px 12px; margin-bottom: 4px; display: flex; align-items: center; justify-content: space-between; direction: ltr; text-align: left;';

            const infoWrapper = document.createElement('div');
            
            const phoneSpan = document.createElement('span');
            phoneSpan.style.cssText = 'font-weight: bold; color: #334155;';
            phoneSpan.innerHTML = `<i class="fa-solid fa-phone" style="color: #10b981; margin-right: 5px;"></i>${rec.phone}`;

            const nameSpan = document.createElement('span');
            nameSpan.style.cssText = 'font-size: 11px; color: var(--text-muted);';
            nameSpan.innerHTML = ` <i class="fa-solid fa-user" style="color: #3b82f6; margin-right: 3px; margin-left: 5px;"></i>(Name: ${rec.name})`;

            infoWrapper.appendChild(phoneSpan);
            infoWrapper.appendChild(nameSpan);

            const delBtn = document.createElement('span');
            delBtn.innerHTML = '<i class="fa-solid fa-trash-can"></i>';
            delBtn.style.cssText = 'color:var(--danger); font-size:14px; cursor:pointer; padding: 4px 8px; border-radius: 4px; transition: background 0.2s; margin-left: auto; margin-right: 0;';
            
            delBtn.addEventListener('mouseenter', () => { delBtn.style.background = '#fee2e2'; });
            delBtn.addEventListener('mouseleave', () => { delBtn.style.background = 'transparent'; });
            
            delBtn.addEventListener('click', (e) => {
                e.stopPropagation();
                waRecipients.splice(idx, 1);
                
                const bulkInp = document.getElementById('wa-multiple-numbers');
                if (bulkInp) bulkInp.value = waRecipients.map(r => r.phone).join('\n');
                
                renderWaRecipientsList();
            });

            item.appendChild(infoWrapper);
            item.appendChild(delBtn);
            listContainer.appendChild(item);
        });
    }

    // ============================================================================
    // Broadcast message templates manager
    // ============================================================================
    function renderWaTemplatesDropdown() {
        const select = document.getElementById('wa-template-select');
        if (!select) return;
        select.innerHTML = '<option value="">-- Select a saved broadcast template --</option>';
        waTemplates.forEach(t => {
            const opt = document.createElement('option');
            opt.value = t.id;
            opt.textContent = `📝 ${t.name}`;
            select.appendChild(opt);
        });
    }

    async function saveWhatsAppTemplate() {
        const msgTextarea = document.getElementById('wa-message-text');
        if (!msgTextarea) return;
        const text = msgTextarea.value.trim();
        if (!text) {
            alert('Save aborted: Please write message copy before saving as template.');
            return;
        }
        const name = prompt('Enter a descriptive name for your new broadcast template:');
        if (!name) return;

        const sanitizedName = sanitizeDynamicString(name);
        waTemplates.push({ id: 'wat_' + Date.now(), name: sanitizedName, text: text });
        
        await saveTemplatesSecurely();
        renderWaTemplatesDropdown();
        
        if (typeof window.addLog === 'function') {
            window.addLog(`Successfully saved new message template under descriptive name: "[${sanitizedName}]".`, 'success');
        }
    }

    function loadWhatsAppTemplate(e) {
        const selectId = e.target.value;
        if (!selectId) return;
        const template = waTemplates.find(t => t.id === selectId);
        if (template) {
            const msgTextarea = document.getElementById('wa-message-text');
            if (msgTextarea) {
                msgTextarea.value = template.text;
            }
        }
    }

    // ============================================================================
    // Exports
    // ============================================================================
    global.FritreeWhatsApp = {
        init: initWhatsAppModule,
        getRecipients: () => waRecipients,
        getMedia: () => Promise.resolve(null), 
        clearRecipients: clearWaRecipientsList,
        updatePreview: () => {}, 
        setRecipients: (list) => {
            if (Array.isArray(list)) {
                waRecipients = list.map(item => ({
                    phone: cleanPhoneNumber(item.phone || item),
                    name: sanitizeDynamicString(item.name || 'Recipient')
                }));

                const bulkInp = document.getElementById('wa-multiple-numbers');
                if (bulkInp) {
                    bulkInp.value = waRecipients.map(r => r.phone).join('\n');
                }

                renderWaRecipientsList();
            }
        }
    };

    if (document.readyState === 'complete' || document.readyState === 'interactive') {
        initWhatsAppModule();
    } else {
        document.addEventListener('DOMContentLoaded', () => initWhatsAppModule());
    }

})(typeof globalThis !== 'undefined' ? globalThis : typeof window !== 'undefined' ? window : this);