track/backend/app/services/label_service.py

"""标签打印服务 — 工业级精确定位标签 (480×360) + TSPL 发送"""
import base64
import socket
from io import BytesIO
from pathlib import Path
from typing import Optional

import qrcode
from PIL import Image, ImageDraw, ImageFont

from app.services.print_config import PrintConfigManager

# ============================================================
# 字体 — 项目内 simhei.ttf
# ============================================================

_FONT_PATH = str(Path(__file__).resolve().parent.parent.parent / "simhei.ttf")

FONT_NORMAL = ImageFont.truetype(_FONT_PATH, 28)   # 右侧：名/规/单
FONT_LARGE = ImageFont.truetype(_FONT_PATH, 34)    # 底部：序列号

# ============================================================
# 画布 & 坐标常量
# ============================================================

WIDTH, HEIGHT = 480, 360
QR_X, QR_Y = 24, 60
QR_SIZE = 180
TEXT_X = 228
TEXT_MAX_W = WIDTH - TEXT_X - 12        # ~240px
BOTTOM_Y = 260                          # 序列号 y
LINE_H = 44                             # 28px 行高

# ============================================================
# QR 码
# ============================================================

def _generate_qr(content: str) -> Image.Image:
    qr = qrcode.QRCode(
        version=1,
        error_correction=qrcode.constants.ERROR_CORRECT_M,
        box_size=10,
        border=2,
    )
    qr.add_data(content)
    qr.make(fit=True)
    img = qr.make_image(fill_color="black", back_color="white")
    return img.resize((QR_SIZE, QR_SIZE), Image.NEAREST)


# ============================================================
# 文字绘制 — 带描边 + 自动换行
# ============================================================

def _draw(
    draw: ImageDraw.Draw,
    text: str,
    x: int,
    y: int,
    font: ImageFont.FreeTypeFont,
    max_width: int,
    stroke_width: int = 1,
) -> int:
    """
    绘制文字，超出 max_width 自动折行。
    返回下一行可用的 y 坐标。
    """
    if not text:
        return y + LINE_H

    # 单行不超宽 → 直接画（带描边）
    bbox = draw.textbbox((0, 0), text, font=font)
    if bbox[2] - bbox[0] <= max_width:
        draw.text((x, y), text, font=font, fill="black",
                  stroke_width=stroke_width, stroke_fill="black")
        return y + LINE_H

    # 逐字符折行
    lines: list[str] = []
    current = ""
    for char in text:
        test = current + char
        w = draw.textbbox((0, 0), test, font=font)[2]
        if w <= max_width:
            current = test
        else:
            lines.append(current)
            current = char
    if current:
        lines.append(current)

    cy = y
    for line in lines:
        draw.text((x, cy), line, font=font, fill="black",
                  stroke_width=stroke_width, stroke_fill="black")
        cy += LINE_H
    return cy


# ============================================================
# 标签绑制 — 工业级精确坐标
# ============================================================

def _create_label(data: dict) -> Image.Image:
    """
    480×360 工业级排版：

       ┌───────────────┬──────────────────────────────┐
       │               │  名: 样品升降台V1J   y=60    │  ← 28px sw=1
       │   [QR Code]   │  规: PH-B4V1J/类A   y=104   │
       │   180×180     │  单: ORD-2024-001   y=148   │
       │   (24, 60)    │                              │
       │               │                              │
       │   码: 0000000000000001               y=260   │  ← 34px sw=2
       └───────────────┴──────────────────────────────┘
    """
    img = Image.new("RGB", (WIDTH, HEIGHT), color="white")
    draw = ImageDraw.Draw(img)

    serial = data.get("serial_number", "")

    # ── QR 码 (24, 60) ──
    if serial:
        qr_img = _generate_qr(serial)
        img.paste(qr_img, (QR_X, QR_Y))

    # ── 右侧文字 x=228 — 28px, stroke_width=1 ──
    y = 60

    name = data.get("material_name", "") or "未命名"
    y = _draw(draw, f"名: {name}", TEXT_X, y, FONT_NORMAL, TEXT_MAX_W, stroke_width=1)

    spec = data.get("spec_model", "") or "-"
    y = _draw(draw, f"规: {spec}", TEXT_X, y, FONT_NORMAL, TEXT_MAX_W, stroke_width=1)

    order_no = data.get("order_no", "")
    if order_no and str(order_no).strip():
        y = _draw(draw, f"单: {str(order_no).strip()}", TEXT_X, y, FONT_NORMAL, TEXT_MAX_W, stroke_width=1)

    # ── 底部通栏 (24, 260) — 34px, stroke_width=2 ──
    code = serial or "-"
    draw.text((24, BOTTOM_Y), f"码: {code}", font=FONT_LARGE, fill="black",
              stroke_width=2, stroke_fill="black")

    return img


# ============================================================
# 公开 API
# ============================================================

def generate_preview_image(**data) -> str:
    """返回 Base64 JPEG data URL"""
    img = _create_label(data)
    buf = BytesIO()
    img.save(buf, format="JPEG", quality=92)
    b64 = base64.b64encode(buf.getvalue()).decode()
    return f"data:image/jpeg;base64,{b64}"


def send_to_printer(
    copies: int = 1,
    printer_ip: Optional[str] = None,
    printer_port: Optional[int] = None,
    **data,
) -> dict:
    """二值化 → TSPL → Socket 发送"""
    printer = PrintConfigManager.get_printer("label_printer")
    ip = printer_ip or printer.get("ip", "192.168.9.221")
    port = printer_port or printer.get("port", 9100)

    img_rgb = _create_label(data)
    img_gray = img_rgb.convert("L")
    img_bw = img_gray.point(lambda px: 0 if px < 128 else 255, "1")

    width_bytes = (img_bw.width + 7) // 8
    height_dots = img_bw.height

    tspl = (
        "SIZE 40 mm, 30 mm\r\n"
        "GAP 2 mm, 0 mm\r\n"
        "CLS\r\n"
        "DIRECTION 1\r\n"
    ).encode("gbk", errors="replace")

    bitmap_cmd = f"BITMAP 0,0,{width_bytes},{height_dots},0,".encode("gbk", errors="replace")
    bitmap_data = img_bw.tobytes()
    footer = f"\r\nPRINT 1,{copies}\r\n".encode("gbk", errors="replace")

    payload = tspl + bitmap_cmd + bitmap_data + footer

    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.settimeout(5)
    try:
        s.connect((ip, port))
        s.sendall(payload)
        s.close()
        return {
            "success": True,
            "message": f"打印指令已发送 → {ip}:{port}，份数: {copies}",
            "printer": f"{ip}:{port}",
        }
    except Exception as e:
        return {
            "success": False,
            "message": f"打印机连接失败 ({ip}:{port}): {str(e)}",
            "printer": f"{ip}:{port}",
        }