"""Verify the captured signature lands on the official MCS-150 signature line.

Fills the real MCS-150 AcroForm, extracts the ``certifySignature`` anchor from
the form's own field rectangle, stamps a synthetic drawn signature, renders the
signature page, and asserts a meaningful number of dark pixels fall inside the
recorded signature box (i.e. the signature is on the rule, not floating).

Requires: reportlab, pypdf, pillow, and (for rendering) pdftoppm.
Run from the repo root with a venv that has those installed.
"""
from __future__ import annotations

import base64
import importlib.util
import io
import os
import subprocess
import sys
import tempfile

REPO = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))


def _load(name: str, rel: str):
    spec = importlib.util.spec_from_file_location(name, os.path.join(REPO, rel))
    mod = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(mod)  # type: ignore[union-attr]
    return mod


def _synthetic_signature_png() -> str:
    from PIL import Image, ImageDraw

    im = Image.new("RGBA", (600, 140), (0, 0, 0, 0))
    d = ImageDraw.Draw(im)
    d.line(
        [(20, 110), (120, 30), (220, 110), (340, 40), (480, 100), (580, 50)],
        fill=(10, 20, 60, 255),
        width=6,
    )
    buf = io.BytesIO()
    im.save(buf, "PNG")
    return base64.b64encode(buf.getvalue()).decode()


def main() -> int:
    sys.path.insert(0, REPO)
    mcs = _load("mcs150_pdf_filler", "scripts/document_gen/templates/mcs150_pdf_filler.py")
    stamper = _load("signature_stamper", "scripts/workers/services/signature_stamper.py")

    intake = {
        "legal_name": "ADAMS LUMBER INC",
        "dot_number": "1157913",
        "entity_type": "corporation",
        "carrier_operation": "authorized_for_hire",
        "interstate_intrastate": "interstate",
        "hazmat": "no",
        "power_units": "5",
        "drivers": "6",
        "annual_miles": "250000",
        "cargo_types": ["general"],
        "signer_name": "Mark Adams",
        "signer_title": "President",
        "address_state": "OR",
        "email": "m@a.com",
    }
    pdf_path = mcs.fill_mcs150(intake, order_number="TEST-MCS150-SIG")
    pdf_bytes = open(pdf_path, "rb").read()

    anchors = stamper.anchors_from_acroform(pdf_bytes, {"certifySignature": "signer"})
    assert anchors, "no signature anchor extracted from MCS-150 AcroForm"
    box = anchors[0]
    print("signature anchor:", box)

    signed = stamper.stamp_signature(
        pdf_bytes,
        anchors,
        signature_type="drawn",
        signature_data=_synthetic_signature_png(),
    )

    with tempfile.TemporaryDirectory() as td:
        signed_path = os.path.join(td, "signed.pdf")
        open(signed_path, "wb").write(signed)
        page_no = box["page"] + 1
        prefix = os.path.join(td, "render")
        subprocess.run(
            ["pdftoppm", "-png", "-f", str(page_no), "-l", str(page_no), "-r", "150", signed_path, prefix],
            check=True,
            stdout=subprocess.DEVNULL,
            stderr=subprocess.DEVNULL,
        )
        # pdftoppm zero-pads the page number; find the produced PNG.
        png = next(
            os.path.join(td, f) for f in sorted(os.listdir(td)) if f.startswith("render") and f.endswith(".png")
        )
        from PIL import Image

        im = Image.open(png).convert("L")
        W, H = im.size
        px = im.load()
        sc = 150 / 72.0
        bx, by, bw, bh = box["x"], box["y"], box["w"], box["h"]
        dark = 0
        for X in range(int(bx * sc), int((bx + bw) * sc)):
            for Y in range(int(H - (by + bh) * sc), int(H - by * sc)):
                if 0 <= X < W and 0 <= Y < H and px[X, Y] < 120:
                    dark += 1
        print("dark signature pixels inside MCS-150 signature box:", dark)
        assert dark > 500, f"signature not on the line (only {dark} dark px in box)"

    print("PASS: signature stamped on the MCS-150 signature line")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())