"""
出入库模块服务层 - SN码生成、Excel导入导出
"""
import io
from datetime import datetime
from django.db import transaction
from openpyxl import Workbook, load_workbook
from openpyxl.drawing.image import Image as XLImage
import qrcode
from io import BytesIO

from apps.devices.models import DeviceType, DeviceBatch, Device


def generate_production_week(date):
    """
    生成生产周格式: YYWXX
    :param date: 日期对象
    :return: 如 25W45
    """
    year = date.year % 100
    week = date.isocalendar()[1]
    return f"{year}W{week:02d}"


def generate_sn_code(brand, product_code, production_week, batch_no, sequence):
    """
    生成SN码
    格式: {品牌}-{产品代号}-{生产周}-{批次号}-{5位序列号}
    示例: AL-DZBJ-ON-25W45-A01-00001
    """
    return f"{brand}-{product_code}-{production_week}-{batch_no}-{sequence:05d}"


def generate_batch_devices(batch):
    """
    为批次生成设备和SN码
    :param batch: DeviceBatch对象
    :return: 生成的Device列表
    """
    device_type = batch.device_type
    brand = device_type.brand
    product_code = device_type.product_code
    production_week = batch.production_week or generate_production_week(batch.production_date)
    batch_no = batch.batch_no
    
    # 更新生产周
    if not batch.production_week:
        batch.production_week = production_week
        batch.save(update_fields=['production_week'])
    
    devices = []
    for i in range(1, batch.quantity + 1):
        sn = generate_sn_code(brand, product_code, production_week, batch_no, i)
        device = Device(
            sn=sn,
            device_type=device_type,
            batch=batch,
            status='in_stock'
        )
        devices.append(device)
    
    # 批量创建
    Device.objects.bulk_create(devices)
    
    # 更新批次状态
    batch.status = 'generated'
    batch.save(update_fields=['status'])
    
    return devices


def generate_qrcode_image(data, size=100):
    """
    生成二维码图片
    :param data: 二维码内容
    :param size: 尺寸
    :return: BytesIO对象
    """
    qr = qrcode.QRCode(
        version=1,
        error_correction=qrcode.constants.ERROR_CORRECT_L,
        box_size=4,
        border=1,
    )
    qr.add_data(data)
    qr.make(fit=True)
    
    img = qr.make_image(fill_color="black", back_color="white")
    img_io = BytesIO()
    img.save(img_io, format='PNG')
    img_io.seek(0)
    return img_io


def export_batch_excel(batch):
    """
    导出批次SN码Excel
    包含四列: SN码 / MAC地址 / 创建时间 / SN码二维码
    :param batch: DeviceBatch对象
    :return: BytesIO对象（Excel文件）
    """
    wb = Workbook()
    ws = wb.active
    ws.title = f"批次{batch.batch_no}"
    
    # 设置表头
    headers = ['SN码', 'MAC地址', '创建时间', 'SN码二维码']
    for col, header in enumerate(headers, 1):
        ws.cell(row=1, column=col, value=header)
    
    # 设置列宽
    ws.column_dimensions['A'].width = 35
    ws.column_dimensions['B'].width = 20
    ws.column_dimensions['C'].width = 22
    ws.column_dimensions['D'].width = 15
    
    # 获取批次设备
    devices = Device.objects.filter(batch=batch).order_by('sn')
    
    for row, device in enumerate(devices, 2):
        ws.cell(row=row, column=1, value=device.sn)
        ws.cell(row=row, column=2, value=device.mac_address or '')
        ws.cell(row=row, column=3, value=device.created_at.strftime('%Y-%m-%d %H:%M:%S'))
        
        # 生成二维码并嵌入
        try:
            qr_img = generate_qrcode_image(device.sn)
            img = XLImage(qr_img)
            img.width = 60
            img.height = 60
            ws.add_image(img, f'D{row}')
            ws.row_dimensions[row].height = 50
        except Exception:
            ws.cell(row=row, column=4, value='[QR]')
    
    # 保存到内存
    output = BytesIO()
    wb.save(output)
    output.seek(0)
    
    return output


def import_mac_addresses(batch, file_obj):
    """
    导入MAC地址
    :param batch: DeviceBatch对象
    :param file_obj: Excel文件对象
    :return: 导入结果字典
    """
    result = {
        'total': 0,
        'success': 0,
        'failed': 0,
        'errors': []
    }
    
    try:
        wb = load_workbook(file_obj)
        ws = wb.active
    except Exception as e:
        result['errors'].append({'row': 0, 'error': f'文件格式错误: {str(e)}'})
        return result
    
    # 跳过表头
    rows = list(ws.iter_rows(min_row=2, values_only=True))
    result['total'] = len(rows)
    
    for row_num, row in enumerate(rows, 2):
        if len(row) < 2:
            continue
        
        sn = row[0]
        mac = row[1]
        
        if not sn or not mac:
            continue
        
        # 统一MAC地址格式
        mac = str(mac).upper().replace('-', ':').strip()
        
        # 验证MAC地址格式
        import re
        if not re.match(r'^([0-9A-F]{2}:){5}[0-9A-F]{2}$', mac):
            result['failed'] += 1
            result['errors'].append({
                'row': row_num,
                'sn': sn,
                'mac': mac,
                'error': 'MAC地址格式不正确'
            })
            continue
        
        try:
            device = Device.objects.get(sn=sn, batch=batch)
        except Device.DoesNotExist:
            result['failed'] += 1
            result['errors'].append({
                'row': row_num,
                'sn': sn,
                'mac': mac,
                'error': 'SN码不存在或不属于当前批次'
            })
            continue
        
        # 检查MAC地址是否已被使用
        existing = Device.objects.filter(mac_address=mac).exclude(id=device.id).first()
        if existing:
            result['failed'] += 1
            result['errors'].append({
                'row': row_num,
                'sn': sn,
                'mac': mac,
                'error': f'MAC地址已被设备 {existing.sn} 使用'
            })
            continue
        
        # 更新MAC地址
        device.mac_address = mac
        device.save(update_fields=['mac_address'])
        result['success'] += 1
    
    return result