import * as db from '../../db/posterminal.js';
import { emit } from '../../api/sse.js';

/**
 * @openapi
 * /v1/init:
 *   get:
 *     tags: [POS]
 *     summary: POS sync initialization counts
 *     description: |
 *       Returns entity change counts since the provided `lastChanged*` sync queue ID cursors
 *       (`posterminalsyncqueue.id` / `posterminalobituary.id`) for the authenticated POS terminal
 *       (`Authorization: Bearer <authToken>`).
 *     x-markdown: pos/init.md
 *     parameters:
 *       - in: header
 *         name: Authorization
 *         required: true
 *         schema:
 *           type: string
 *         description: POS device authToken obtained during pairing (`Bearer <token>` or `<token>`)
 *         example: "Bearer c30099b66ec1fcb9ccd05795423c94e8"
 *       - in: header
 *         name: version
 *         required: false
 *         schema:
 *           type: string
 *         description: POS client software version reported by the device
 *         example: "2.0.0.5"
 *       - in: query
 *         name: lastChangedProduct
 *         required: false
 *         schema:
 *           type: integer
 *           default: 0
 *         description: Sequential ID cursor of last synced product entry (`posterminalsyncqueue.id`)
 *         example: 0
 *       - in: query
 *         name: lastChangedCategory
 *         required: false
 *         schema:
 *           type: integer
 *           default: 0
 *         description: Sequential ID cursor of last synced category entry (`posterminalsyncqueue.id`)
 *         example: 0
 *       - in: query
 *         name: lastChangedCustomer
 *         required: false
 *         schema:
 *           type: integer
 *           default: 0
 *         description: Sequential ID cursor of last synced customer entry (`posterminalsyncqueue.id`)
 *         example: 0
 *       - in: query
 *         name: lastChangedCustomerGroup
 *         required: false
 *         schema:
 *           type: integer
 *           default: 0
 *         description: Sequential ID cursor of last synced customer group entry (`posterminalsyncqueue.id`)
 *         example: 0
 *       - in: query
 *         name: lastChangedCompositeProduct
 *         required: false
 *         schema:
 *           type: integer
 *           default: 0
 *         description: Sequential ID cursor of last synced composite product entry (`posterminalsyncqueue.id`)
 *         example: 0
 *       - in: query
 *         name: lastChangedDeletedEntity
 *         required: false
 *         schema:
 *           type: integer
 *           default: 0
 *         description: Sequential ID cursor of last synced deleted entity (`posterminalobituary.id`)
 *         example: 0
 *     responses:
 *       200:
 *         description: Sync initialization counts
 *         content:
 *           application/json:
 *             schema:
 *               type: object
 *               properties:
 *                 version:
 *                   type: string
 *                   example: "1.10.12.0"
 *                 product_count:
 *                   type: string
 *                   example: "19"
 *                 category_count:
 *                   type: string
 *                   example: "4"
 *                 customer_count:
 *                   type: string
 *                   example: "0"
 *                 customerGroup_count:
 *                   type: string
 *                   example: "1"
 *                 compositeProduct_count:
 *                   type: string
 *                   example: "0"
 *                 configurationGroup_count:
 *                   type: string
 *                   example: "0"
 *                 configurationItem_count:
 *                   type: string
 *                   example: "0"
 *                 deletedEntity_count:
 *                   type: string
 *                   example: "0"
 *                 max_orderId_count:
 *                   type: string
 *                   example: "0"
 *       401:
 *         description: Missing or invalid POS Authorization token
 *         content:
 *           application/json:
 *             schema:
 *               type: object
 *               properties:
 *                 Message:
 *                   type: string
 *                   example: "Authorization has been denied for this request."
 * @param {import('express').Request} req
 * @param {import('express').Response} res
 */
export async function handleInit(req, res) {
    const posterminalId = req.posterminal.id;

    const rawVersion = req.headers.version || req.headers.clientversion;
    const incomingVersion = rawVersion ? String(rawVersion).trim() : '';
    const currentVersion = req.posterminal.clientversion ? String(req.posterminal.clientversion).trim() : '';

    const updateVersionPromise = (incomingVersion && incomingVersion !== currentVersion)
        ? db.setClientversion(posterminalId, incomingVersion)
            .then(() => {
                req.posterminal.clientversion = incomingVersion;
                if (req.posterminal.companyId) {
                    emit('posterminal', { companyId: req.posterminal.companyId });
                }
            })
            .catch((err) => {
                console.error(`Failed to update posterminal ${posterminalId} version:`, err);
            })
        : null;

    const productCursor = Number(req.query.lastChangedProduct) || 0;
    const categoryCursor = Number(req.query.lastChangedCategory) || 0;
    const customerCursor = Number(req.query.lastChangedCustomer) || 0;
    const customerGroupCursor = Number(req.query.lastChangedCustomerGroup) || 0;
    const compositeProductCursor = Number(req.query.lastChangedCompositeProduct) || 0;
    const deletedEntityCursor = Number(req.query.lastChangedDeletedEntity) || 0;

    try {
        const [
            productCount,
            categoryCount,
            customerCount,
            customerGroupCount,
            compositeProductCount,
            deletedEntityCount,
            maxOrderIdCount,
        ] = await Promise.all([
            db.getProductCount({ posterminalId, cursor: productCursor }),
            db.getCategoryCount({ posterminalId, cursor: categoryCursor }),
            db.getCustomerCount({ posterminalId, cursor: customerCursor }),
            db.getCustomerGroupCount({ posterminalId, cursor: customerGroupCursor }),
            db.getCompositeProductCount({ posterminalId, cursor: compositeProductCursor }),
            db.getDeletedEntityCount({ posterminalId, cursor: deletedEntityCursor }),
            db.getMaxOrderIdCount({ posterminalId }),
            updateVersionPromise,
        ]);

        return res.status(200).json({
            version: '1.10.12.0',
            product_count: String(productCount),
            category_count: String(categoryCount),
            customer_count: String(customerCount),
            customerGroup_count: String(customerGroupCount),
            compositeProduct_count: String(compositeProductCount),
            configurationGroup_count: '0',
            configurationItem_count: '0',
            deletedEntity_count: String(deletedEntityCount),
            max_orderId_count: String(maxOrderIdCount),
        });
    } catch (err) {
        console.error('POS /v1/init error:', err);
        return res.status(500).json({ Message: 'Internal server error' });
    }
}