"""Save or update a distribution agreement product discount."""
agreement_id = params_kw.get('agreement_id')
productid = params_kw.get('productid')
prodtypeid = params_kw.get('prodtypeid') or ''
new_discount = params_kw.get('discount') or '1.0'
old_discount = params_kw.get('old_discount') or '1.0'
item_id = params_kw.get('item_id')

userorgid = (await get_userorgid()) or '0'
dbname = get_module_dbname('supplychain')

async with DBPools().sqlorContext(dbname) as sor:
    if item_id:
        # Existing item — update or delete
        if new_discount == old_discount:
            # No change, skip
            pass
        elif float(new_discount) <= 0:
            # Delete if discount set to 0
            await sor.D('distribution_agreement_items', {'id': item_id})
            # Also remove product_org_auth
            async with DBPools().sqlorContext('sage') as s2:
                await s2.sqlExe("DELETE FROM product_org_auth WHERE auth_source_id = ${sid}$", {'sid': item_id})
        else:
            await sor.U('distribution_agreement_items', {
                'id': item_id, 'discount': new_discount, 'updated_at': timestampstr()
            })
    elif float(new_discount) > 0 and new_discount != old_discount:
        # New item — create
        item_id = getID()
        now = timestampstr()
        await sor.C('distribution_agreement_items', {
            'id': item_id, 'agreement_id': agreement_id, 'resellerid': userorgid,
            'productid': productid, 'prodtypeid': prodtypeid,
            'discount': new_discount, 'created_at': now,
        })
        # Sync product_org_auth (upsert — skip if exists)
        async with DBPools().sqlorContext(dbname) as s2:
            ag = await s2.sqlExe(
                "SELECT sub_reseller_id FROM distribution_agreements WHERE id = ${aid}$",
                {'aid': agreement_id}
            )
        if ag:
            async with DBPools().sqlorContext('sage') as s3:
                existing = await s3.sqlExe(
                    "SELECT id FROM product_org_auth WHERE product_id = ${pid}$ AND org_id = ${oid}$",
                    {'pid': productid, 'oid': ag[0].sub_reseller_id}
                )
                if not existing:
                    await s3.C('product_org_auth', {
                        'id': getID(), 'product_id': productid,
                        'org_id': ag[0].sub_reseller_id,
                        'auth_source': 'distribution_agreement', 'auth_source_id': item_id,
                    })

return {'status': 'ok', 'item_id': item_id or '', 'discount': new_discount, 'productid': productid}