"""pytest fixtures：用 reportlab 生成 3 个样例 PDF（中文字体 STSong-Light）。"""

import io

import pytest
from reportlab.lib.pagesizes import A4
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.cidfonts import UnicodeCIDFont
from reportlab.pdfgen import canvas

pdfmetrics.registerFont(UnicodeCIDFont("STSong-Light"))


def _idcard_fix(prefix17: str) -> str:
    w = [7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2]
    c = "10X98765432"
    total = sum(int(prefix17[i]) * w[i] for i in range(17))
    return prefix17 + c[total % 11]


def _luhn_fix(prefix: str) -> str:
    for last in "0123456789":
        s = prefix + last
        total, alt = 0, False
        for ch in reversed(s):
            d = int(ch)
            if alt:
                d *= 2
                if d > 9:
                    d -= 9
            total += d
            alt = not alt
        if total % 10 == 0:
            return s
    raise RuntimeError("no luhn digit")


VALID_ID = _idcard_fix("11010119900307759")  # 程序化补校验位，保证合法
BANK_CARD = _luhn_fix("622202020011223344")  # 19 位，Luhn 合法
PHONE = "13812345678"
EMAIL = "zhang.san@example.com"


def _make_pdf(pages):
    """pages: List[str]，每页一段文本；空字符串 = 空白页（模拟扫描页）。"""
    buf = io.BytesIO()
    c = canvas.Canvas(buf, pagesize=A4)
    for text in pages:
        if text:
            y = 750
            for line in text.split("\n"):
                c.setFont("STSong-Light", 12)
                c.drawString(72, y, line)
                y -= 24
        c.showPage()
    c.save()
    return buf.getvalue()


@pytest.fixture(scope="module")
def pdf_plain():
    """样例1：纯文本页（无 PII）。"""
    return _make_pdf(["本判决书仅供学习参考。\n案号：（2026）京01民初1号。\n审判员：李四。"])


@pytest.fixture(scope="module")
def pdf_pii():
    """样例2：含身份证 + 手机号 + 银行卡 + 邮箱。"""
    return _make_pdf([
        f"原告：张三，身份证号 {VALID_ID}，联系电话 {PHONE}。\n"
        f"收款账户：{BANK_CARD}，邮箱 {EMAIL}。\n"
        "以上信息用于测试脱敏。"
    ])


@pytest.fixture(scope="module")
def pdf_scanned():
    """样例3：空白扫描页（无文字层）。"""
    return _make_pdf([""])