src/scenes/admin/broadcast.js

const { Scenes, Markup } = require('telegraf');
const User = require('../../models/User');
const userController = require('../../controllers/userController');

const broadcastScene = new Scenes.WizardScene(
    'BROADCAST_SCENE',
    // Step 1: Ask for content
    async (ctx) => {
        // Ensure localization
        if (!ctx.i18n) {
            const locales = require('../../locales');
            const User = require('../../models/User');
            const user = await User.findOne({ id: ctx.from.id });
            ctx.i18n = locales[user ? user.language : 'uz'];
        }
        const i18n = ctx.i18n;

        ctx.reply(i18n.admin.broadcast_prompt, Markup.keyboard([[i18n.btn_cancel]]).resize());
        return ctx.wizard.next();
    },
    // Step 2: Confirm
    (ctx) => {
        const i18n = ctx.i18n;
        if (ctx.message && (ctx.message.text === '/cancel' || ctx.message.text === i18n.btn_cancel)) {
            ctx.scene.leave();
            userController.start(ctx, i18n.cancel_process);
            return;
        }

        // Handle Back from Step 3 (Logic if needed, but Step 3 handles it mostly)
        if (ctx.message && ctx.message.text === i18n.btn_back_nav) {
            ctx.reply(i18n.admin.broadcast_prompt, Markup.keyboard([[i18n.btn_cancel]]).resize());
            return ctx.wizard.back();
        }

        ctx.wizard.state.message = ctx.message; // Save the message object

        // Show Preview (Forward copy)
        ctx.copyMessage(ctx.from.id, ctx.message.message_id);

        ctx.reply(i18n.admin.broadcast_confirm, Markup.inlineKeyboard([
            Markup.button.callback(i18n.admin.broadcast_send, "confirm_send"),
            Markup.button.callback(i18n.admin.broadcast_change, "back_to_start"),
            Markup.button.callback(i18n.btn_cancel, "cancel_send")
        ]));
        return ctx.wizard.next();
    },
    // Step 3: Action Handler
    async (ctx) => {
        const i18n = ctx.i18n;
        if (ctx.callbackQuery) {
            const action = ctx.callbackQuery.data;
            if (action === 'cancel_send') {
                ctx.deleteMessage();
                ctx.scene.leave();
                userController.start(ctx, i18n.cancel_process);
                return;
            } else if (action === 'back_to_start') {
                ctx.deleteMessage();
                ctx.reply(i18n.admin.broadcast_prompt, Markup.keyboard([[i18n.btn_cancel]]).resize());
                return ctx.wizard.back();
            } else if (action === 'confirm_send') {
                await ctx.deleteMessage();
                ctx.reply(i18n.admin.broadcast_sending);

                // Start sending
                const users = await User.find();
                let success = 0;
                let blocked = 0;

                const messageId = ctx.wizard.state.message.message_id;
                // Optimized Broadcast with Batching
                const sleep = (ms) => new Promise(r => setTimeout(r, ms));
                const BATCH_SIZE = 20;

                for (let i = 0; i < users.length; i += BATCH_SIZE) {
                    const batch = users.slice(i, i + BATCH_SIZE);
                    await Promise.all(batch.map(async (user) => {
                        try {
                            await ctx.copyMessage(user.id, messageId);
                            success++;
                        } catch (err) {
                            blocked++;
                        }
                    }));
                    await sleep(1000); // 1 sec limit to respect telegram API limits
                }

                ctx.reply(`${i18n.admin.broadcast_finish}\n\n✅: ${success}\n🚫: ${blocked}`);
                userController.start(ctx); // Return to menu
                return ctx.scene.leave();
            }
        } else {
            // Handle text input during buttonwait?
            if (ctx.message && ctx.message.text === i18n.btn_cancel) {
                ctx.scene.leave();
                userController.start(ctx, i18n.cancel_process);
                return;
            }
        }
    }
);

module.exports = broadcastScene;