"""Verify the e-signature lands exactly on the signature line of the auth form.

Renders the authorization PDF, captures the signature-box anchors, creates a
synthetic drawn signature, stamps it, and asserts the stamped ink falls inside
the recorded signature box (and on/just-above the signature rule).
"""
import base64
import io
import os
import sys

_SVC = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "workers", "services"))
sys.path.insert(0, _SVC)

import signature_stamper  # noqa: E402
from state_trucking_authorization import (  # noqa: E402
    build_state_trucking_authorization,
)


def make_signature_png(w=600, h=200) -> bytes:
    """A black squiggle on transparent background -> base64 PNG."""
    from PIL import Image, ImageDraw

    im = Image.new("RGBA", (w, h), (0, 0, 0, 0))
    d = ImageDraw.Draw(im)
    pts = [(20, 150), (120, 40), (220, 160), (320, 50), (430, 150), (560, 60)]
    d.line(pts, fill=(10, 20, 60, 255), width=8, joint="curve")
    buf = io.BytesIO()
    im.save(buf, "PNG")
    return buf.getvalue()


def main() -> int:
    pdf, anchors = build_state_trucking_authorization(
        order_number="CO-TEST1234",
        entity_name="Acme Freight LLC",
        service_name="New York Highway Use Tax (HUT) Registration",
        dot_number="3456789",
        mc_number="MC-987654",
        fein_last4="1234",
        base_state="NY",
        operating_states=["NY", "PA", "OH"],
        signer_name="John Smith",
        signer_title="Owner",
    )
    assert pdf[:4] == b"%PDF", "generator did not emit a PDF"
    signer_anchor = next(a for a in anchors if a["field"] == "signer")
    print(f"signer box: x={signer_anchor['x']:.1f} y={signer_anchor['y']:.1f} "
          f"w={signer_anchor['w']:.1f} h={signer_anchor['h']:.1f}")

    sig_png = make_signature_png()
    sig_b64 = "data:image/png;base64," + base64.b64encode(sig_png).decode()

    signed = signature_stamper.stamp_signature(
        pdf,
        anchors,
        signature_type="drawn",
        signature_data=sig_b64,
        signer_field="signer",
    )
    assert signed[:4] == b"%PDF", "stamper did not emit a PDF"
    assert len(signed) > len(pdf), "stamped PDF should be larger (image added)"

    # Render the signed PDF to an image and confirm dark ink appears inside the
    # signature box and essentially nowhere far outside it.
    try:
        from pdf2image import convert_from_bytes
    except ImportError:
        print("pdf2image not installed — skipping pixel check (PDF structure OK)")
        with open("/tmp/state_trucking_authorization_signed.pdf", "wb") as f:
            f.write(signed)
        print("wrote /tmp/state_trucking_authorization_signed.pdf")
        return 0

    pages = convert_from_bytes(signed, dpi=150)
    page = pages[0]
    pw, ph = page.size
    # PDF points -> pixels (origin top-left in image, bottom-left in PDF)
    scale = pw / 612.0
    bx = signer_anchor["x"] * scale
    bw = signer_anchor["w"] * scale
    by_top = (792.0 - (signer_anchor["y"] + signer_anchor["h"])) * scale
    bh = signer_anchor["h"] * scale

    px = page.convert("L").load()
    ink_in_box = 0
    for yy in range(int(by_top) - 4, int(by_top + bh) + 6):
        for xx in range(int(bx) - 4, int(bx + bw) + 4):
            if 0 <= xx < pw and 0 <= yy < ph and px[xx, yy] < 90:
                ink_in_box += 1
    print(f"dark signature pixels inside signature box: {ink_in_box}")
    assert ink_in_box > 200, "signature ink not found on the signature line!"

    with open("/tmp/state_trucking_authorization_signed.pdf", "wb") as f:
        f.write(signed)
    print("PASS: signature stamped on the signature line")
    print("wrote /tmp/state_trucking_authorization_signed.pdf")
    return 0


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