// src/services/whatsappService.js
const { randomDelay, sleep } = require('../utils');
const logger = require('../logger');
const config = require('../config');

let sockInstance = null;

/**
 * Initializes the WhatsApp Service with the Baileys socket instance.
 * Should be called once after connection is established.
 * @param {object} sock - The Baileys socket instance.
 */
function initialize(sock) {
    if (!sockInstance) {
        sockInstance = sock;
        logger.info('WhatsApp Service Initialized.');
    }
}

/**
 * Sends a presence update (typing, paused, available, unavailable).
 * @param {'composing' | 'paused' | 'available' | 'unavailable'} status - The presence status.
 * @param {string} jid - The target JID.
 */
async function sendPresenceUpdate(status, jid) {
    if (!sockInstance) return logger.error('WhatsApp Service not initialized for sendPresenceUpdate');
    try {
        await sockInstance.sendPresenceUpdate(status, jid);
    } catch (err) {
        logger.error({ err, jid, status }, '[WhatsAppService] Failed to send presence update');
    }
}

/**
 * Marks specific messages as read.
 * @param {Array<object>} keys - An array of message key objects.
 */
async function readReceipt(keys) {
     if (!sockInstance) return logger.error('WhatsApp Service not initialized for readReceipt');
     try {
        await sockInstance.readMessages(keys);
        // Log the first key for brevity if needed
        if (keys && keys[0]) {
            logger.debug({ jid: keys[0].remoteJid, msgId: keys[0].id }, `[WhatsAppService] Marked message(s) as read`);
        }
     } catch (err) {
        const jid = keys && keys[0] ? keys[0].remoteJid : 'unknown';
        logger.warn({ err, jid }, '[WhatsAppService] Failed to mark message(s) as read');
     }
}

/**
 * Sends a message with simulated typing and random delay.
 * @param {string} jid - The target JID.
 * @param {object} message - The Baileys message object (e.g., { text: 'Hello' }).
 * @param {object} [options={}] - Options object.
 * @param {number} [options.minDelay] - Minimum delay (defaults to config.defaultMinDelay).
 * @param {number} [options.maxDelay] - Maximum delay (defaults to config.defaultMaxDelay).
 * @returns {Promise<object|null>} - The result from Baileys sendMessage or null on init error.
 */
async function sendMessageWithTyping(jid, message, options = {}) {
    if (!sockInstance) {
        logger.error({ jid, message }, 'WhatsApp Service not initialized for sendMessage');
        return null; // Indicate failure
    }

    // Use provided delays or fall back to config defaults
    const minDelayMs = options.minDelay ?? config.defaultMinDelay;
    const maxDelayMs = options.maxDelay ?? config.defaultMaxDelay;

    try {
        await sendPresenceUpdate('composing', jid);
        await randomDelay(minDelayMs, maxDelayMs);
        await sendPresenceUpdate('paused', jid); // Clear composing state before sending

        const result = await sockInstance.sendMessage(jid, message);
        logger.debug({ jid, msgContent: message.text || '[Non-Text]' }, '[WhatsAppService] Message sent');
        return result;
    } catch (err) {
        logger.error({ err, jid, msgContent: message.text || '[Non-Text]' }, '[WhatsAppService] Failed to send message');
        // Re-throw error for the calling handler to potentially manage
        // Avoid sending another message from here to prevent loops
        throw err;
    }
}

module.exports = {
    initialize,
    sendMessageWithTyping,
    readReceipt,
    // Only export specific actions needed by handlers
};