# Lay the 2 in stickers out for Printo as a 10-page A4 PDF (one page per kiss-cut sheet), easy to cut apart by hand.
# Each page is an even grid, so a few straight edge-to-edge scissor cuts give single stickers on their backing.
# The five designs come in equal numbers over the 10 pages: each page holds every design as evenly as the grid allows,
# and the leftover slots rotate from page to page.
# Writes <out>.pdf (art + scissor lines + cut line), <out>-art.pdf, <out>-cut.pdf, <out>-pages/page-NN.svg, <out>-preview.png.
# usage: python sheet-layout.py <dir with the 2 in sticker SVGs> <out basename> <columns> <rows>
import io, os, re, sys
import numpy as np, cairosvg
from PIL import Image
from pypdf import PdfWriter, PdfReader

SRC, OUT = sys.argv[1:3]
COLS, ROWS = int(sys.argv[3]), int(sys.argv[4])
DPI, PAGE_W, PAGE_H, PAGES = 300, 2480, 3508, 10
DESIGNS = ["witch-hex-cellent", "bat-going-batty", "vampire-fang-cy", "ghost-boo-always-online", "ghost-no-ghost-customers"]
# Scissor lines: sparse dashes, 3 mm on and 9 mm off, ~0.35 mm thick, in a mid green-grey that shows on white vinyl.
GUIDE = '<g id="ScissorGuides" fill="none" stroke="#5E7370" stroke-width="4" stroke-dasharray="36 106" stroke-linecap="round">{}</g>'

def load(name):
    svg = open(f"{SRC}/{name}.svg").read()
    px = round(float(re.search(r'width="([\d.]+)in"', svg).group(1)) * DPI)
    b, c = svg.index('<g id="bleed"'), svg.index('<g id="CutContour"')
    art = svg[b:c].replace(' id="bleed"', "").replace(' id="artwork"', "")
    cut = svg[c:svg.rindex("</svg>")]
    cut = cut[cut.index(">") + 1: cut.rindex("</g>")]
    filled = f'<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 {px} {px}"><g fill="#000">{cut}</g></svg>'
    m = np.array(Image.open(io.BytesIO(cairosvg.svg2png(bytestring=filled.encode(), output_width=px * 2, output_height=px * 2))).convert("RGBA"))[:, :, 3] > 128
    ys, xs = np.nonzero(m)
    return art, cut, (xs.min() / 2, ys.min() / 2, (xs.max() + 1) / 2, (ys.max() + 1) / 2)

def page_order(p, slots):
    """Cycle through the designs row by row; with 3 columns no design sits beside or above itself."""
    extra = slots % len(DESIGNS)
    shift = (p * extra) % len(DESIGNS)
    order = DESIGNS[shift:] + DESIGNS[:shift]
    return order * (slots // len(DESIGNS)) + order[:extra]

stickers = {n: load(n) for n in DESIGNS}
cw, ch = PAGE_W / COLS, PAGE_H / ROWS
for n, (_, _, (x0, y0, x1, y1)) in stickers.items():
    assert x1 - x0 < cw - 60 and y1 - y0 < ch - 60, f"{n} leaves under 2.5 mm to the scissor line"
lines = "".join(f'<path d="M{cw * i:.1f},0 V{PAGE_H}"/>' for i in range(1, COLS)) + "".join(f'<path d="M0,{ch * j:.1f} H{PAGE_W}"/>' for j in range(1, ROWS))
head = f'<svg xmlns="http://www.w3.org/2000/svg" width="210mm" height="297mm" viewBox="0 0 {PAGE_W} {PAGE_H}">'
os.makedirs(f"{OUT}-pages", exist_ok=True)
full, art_only, cut_only, thumbs, counts = PdfWriter(), PdfWriter(), PdfWriter(), [], {n: 0 for n in DESIGNS}
for p in range(PAGES):
    art, cuts = [], []
    for k, name in enumerate(page_order(p, COLS * ROWS)):
        counts[name] += 1
        a, c, (bx0, by0, bx1, by1) = stickers[name]
        X = (k % COLS) * cw + (cw - (bx1 - bx0)) / 2 - bx0
        Y = (k // COLS) * ch + (ch - (by1 - by0)) / 2 - by0
        art.append(f'<g transform="translate({X:.2f},{Y:.2f})">{a}</g>')
        cuts.append(f'<g transform="translate({X:.2f},{Y:.2f})">{c}</g>')
    art_g = f'<g id="artwork">{"".join(art)}</g>'
    guide_g = GUIDE.format(lines)
    cut_g = f'<g id="CutContour" fill="none" stroke="#EC008C" stroke-width="1">{"".join(cuts)}</g>'
    title = f"<title>MyBazaar Halloween stickers - A4 kiss-cut sheet {p + 1} of {PAGES}, {COLS}x{ROWS} grid of 2 in (AI-generated art)</title>"
    svg = head + title + art_g + guide_g + cut_g + "</svg>"
    open(f"{OUT}-pages/page-{p + 1:02d}.svg", "w").write(svg)
    for writer, body in ((full, svg), (art_only, head + art_g + guide_g + "</svg>"), (cut_only, head + cut_g + "</svg>")):
        writer.add_page(PdfReader(io.BytesIO(cairosvg.svg2pdf(bytestring=body.encode()))).pages[0])
    prev = head + f'<rect width="{PAGE_W}" height="{PAGE_H}" fill="#FFFFFF"/>' + art_g + guide_g + cut_g.replace('stroke-width="1"', 'stroke-width="5"') + "</svg>"
    thumbs.append(Image.open(io.BytesIO(cairosvg.svg2png(bytestring=prev.encode(), output_width=PAGE_W // 4, output_height=PAGE_H // 4))))
for writer, suffix in ((full, ""), (art_only, "-art"), (cut_only, "-cut")):
    with open(f"{OUT}{suffix}.pdf", "wb") as f:
        writer.write(f)
tw, th = thumbs[0].size
sheet = Image.new("RGB", (5 * tw + 6 * 24, 2 * th + 3 * 24), "#C9D3D1")
for i, t in enumerate(thumbs):
    sheet.paste(t, (24 + (i % 5) * (tw + 24), 24 + (i // 5) * (th + 24)))
sheet.save(f"{OUT}-preview.png")
print(f"{COLS}x{ROWS}:", {n: v for n, v in counts.items()}, "total", sum(counts.values()))