KCGL/inventory-backend/app/services/print/label_service.py

import socket
import base64
import os
from io import BytesIO
from PIL import Image, ImageDraw, ImageFont

# 引入条形码生成库
try:
    import barcode
    from barcode.writer import ImageWriter
except ImportError:
    print("❌ 警告: 未安装 python-barcode 库，无法生成真实条形码。请执行: pip install python-barcode")


class LabelPrintService:
    PRINTER_IP = "192.168.9.205"
    PRINTER_PORT = 9100

    # ================= 1. 尺寸与分辨率配置 (300 DPI) =================
    DOTS_PER_MM = 12  # 300 DPI
    LABEL_WIDTH_MM = 40
    LABEL_HEIGHT_MM = 30

    # 画布像素: 40mm -> 480px, 30mm -> 360px
    LABEL_WIDTH = int(LABEL_WIDTH_MM * DOTS_PER_MM)
    LABEL_HEIGHT = int(LABEL_HEIGHT_MM * DOTS_PER_MM)

    # 顶部留白: 10mm (120px) - 内容从这里开始
    TOP_MARGIN_MM = 2
    TOP_MARGIN_PX = int(TOP_MARGIN_MM * DOTS_PER_MM)

    @staticmethod
    def _get_font(size):
        """获取字体"""
        # 尝试加载中文字体，否则乱码
        font_names = ["simhei.ttf", "msyh.ttf", "SimHei.ttf", "arial.ttf"]
        base_dirs = [os.getcwd(), os.path.dirname(__file__)]

        for d in base_dirs:
            for name in font_names:
                path = os.path.join(d, name)
                if os.path.exists(path):
                    return ImageFont.truetype(path, size)
        return ImageFont.load_default()

    @staticmethod
    def _generate_barcode_image(content, width_px, height_px):
        """
        生成真实的条形码图片
        """
        try:
            # 确保内容字符串有效
            if not content:
                content = "0000000000"

            # 使用 Code128 编码（通用性最强）
            code128 = barcode.get('code128', content, writer=ImageWriter())

            # 渲染到内存
            buffer = BytesIO()
            # write_text=False: 不在条码下方生成自带的数字（我们自己画）
            code128.write(buffer, options={"write_text": False, "module_height": 10.0, "quiet_zone": 1.0})

            # 打开生成的条码图
            buffer.seek(0)
            bc_img = Image.open(buffer)

            # 强制调整大小以适应我们的布局
            return bc_img.resize((width_px, height_px), Image.Resampling.LANCZOS)
        except Exception as e:
            print(f"条形码生成失败: {e}")
            # 生成失败时返回一个黑色方块占位
            return Image.new('RGB', (width_px, height_px), color='black')

    @staticmethod
    def _create_image_object(data):
        """
        [绘图层] 生成标签图片
        """
        # 1. 创建画布 (白底)
        img = Image.new('RGB', (LabelPrintService.LABEL_WIDTH, LabelPrintService.LABEL_HEIGHT), color='white')
        d = ImageDraw.Draw(img)

        # 2. 统一字体配置 (字号 30)
        UNIFIED_FONT_SIZE = 30
        font = LabelPrintService._get_font(UNIFIED_FONT_SIZE)

        # 3. 提取条码内容 (优先使用 SKU)
        # 逻辑：使用自动生成的 SKU (如 00000001) 作为条码内容
        sku_code = data.get('sku')
        if not sku_code:
            # 兜底逻辑：如果没有 SKU，尝试用 serial_number 或 global_id
            sku_code = data.get('serial_number') or str(data.get('global_print_id', '0000000000')).zfill(10)

        # ==================== 绘制布局 ====================

        # X 轴偏移 (5mm)
        GLOBAL_OFFSET_X = int(2 * LabelPrintService.DOTS_PER_MM)

        # Y 轴起始: 10mm 处
        CURRENT_Y = LabelPrintService.TOP_MARGIN_PX

        # --- A. 绘制真实条形码 (内容为 SKU) ---
        bc_w = int(35 * LabelPrintService.DOTS_PER_MM)  # 条码宽约 28mm
        bc_h = int(10 * LabelPrintService.DOTS_PER_MM)  # 条码高约 6mm

        # 生成并粘贴条码
        bc_img = LabelPrintService._generate_barcode_image(sku_code, bc_w, bc_h)
        # 粘贴位置: (X, Y)
        img.paste(bc_img, (GLOBAL_OFFSET_X - 10, CURRENT_Y))

        # 更新 Y 坐标 (条码高度 + 间距)
        CURRENT_Y += bc_h + 5

        # --- B. 绘制文字 (统一加粗) ---

        # 准备数据 (名称、规格等)
        name = str(data.get('material_name', '') or '-')
        if len(name) > 8: name = name[:7] + ".."

        spec = str(data.get('spec_model', '') or '-')
        if len(spec) > 11: spec = spec[:10] + ".."

        loc = str(data.get('warehouse_loc', '') or '-')

        cat = str(data.get('category', '') or '')
        typ = str(data.get('material_type', '') or '')
        attr = f"{cat}/{typ}"
        if len(attr) > 11: attr = attr[:10] + ".."

        # -----------------------------------------------------------
        # [修改点] 底部显示的文字：不再显示 NO.SKU，而是显示 SN 或 BN
        # -----------------------------------------------------------
        bottom_text = ""

        # 1. 优先检查前端是否传了明确的 print_no (打印值) 和 print_label (序/批)
        if data.get('print_no'):
            val = str(data.get('print_no'))
            label_type = data.get('print_label', '')

            if label_type == '序':
                bottom_text = f"SN: {val}"
            elif label_type == '批':
                bottom_text = f"BN: {val}"
            else:
                bottom_text = f"NO: {val}"

        # 2. 如果没有前端打印参数，检查数据中的序列号
        elif data.get('serial_number'):
            bottom_text = f"SN: {data.get('serial_number')}"

        # 3. 检查数据中的批号
        elif data.get('batch_number'):
            bottom_text = f"BN: {data.get('batch_number')}"

        # 4. 兜底 (如果什么都没有，才显示 SKU)
        else:
            bottom_text = f"NO: {sku_code}"

        # -----------------------------------------------------------

        lines = [
            f"名: {name}",
            f"规: {spec}",
            f"库: {loc}",
            f"属: {attr}",
            f"{bottom_text}"  # 这里放置计算好的 SN/BN 文字
        ]

        line_height = 36  # 行高 (字号30 + 6间距)

        for line in lines:
            # 边界检查
            if CURRENT_Y + UNIFIED_FONT_SIZE > LabelPrintService.LABEL_HEIGHT:
                break

            # 绘制文字 (stroke_width=1 实现加粗效果)
            d.text((GLOBAL_OFFSET_X, CURRENT_Y), line, font=font, fill='black', stroke_width=1, stroke_fill='black')
            CURRENT_Y += line_height

        return img

    @staticmethod
    def generate_preview_image(data):
        img = LabelPrintService._create_image_object(data)
        output_buffer = BytesIO()
        img.save(output_buffer, format='JPEG')
        base64_str = base64.b64encode(output_buffer.getvalue()).decode('utf-8')
        return f"data:image/jpeg;base64,{base64_str}"

    @staticmethod
    def send_to_printer(data):
        ip = LabelPrintService.PRINTER_IP
        port = LabelPrintService.PRINTER_PORT

        try:
            # 1. 获取图像 (RGB)
            img_rgb = LabelPrintService._create_image_object(data)

            # 2. 图像转二值化 (白=1, 黑=0 的逻辑，不反转)
            img_gray = img_rgb.convert('L')
            img_bw = img_gray.convert('1', dither=Image.Dither.NONE)

            # 获取位图数据
            bitmap_data = img_bw.tobytes()
            width_bytes = (img_bw.width + 7) // 8
            height_dots = img_bw.height

            # 3. TSPL 指令
            header = (
                f"SIZE {LabelPrintService.LABEL_WIDTH_MM} mm, {LabelPrintService.LABEL_HEIGHT_MM} mm\r\n"
                "GAP 2 mm, 0 mm\r\n"
                "CLS\r\n"
                "DIRECTION 1\r\n"
                "REFERENCE 0, 0\r\n"
            ).encode('gbk')

            bitmap_cmd = f"BITMAP 0,0,{width_bytes},{height_dots},0,".encode('gbk')
            footer = b"\r\nPRINT 1,1\r\n"

            # 4. 发送
            s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            s.settimeout(5)
            s.connect((ip, port))
            s.sendall(header + bitmap_cmd + bitmap_data + footer)
            s.close()
            return True

        except Exception as e:
            print(f"❌ 打印异常: {e}")
            raise Exception(f"打印机连接失败: {str(e)}")