lego-instructions-manager/app/routes/labels_dymo.py

"""
Dymo LabelWriter printing - admin only.

The tape printer does one label at a time on a continuous roll. A
LabelWriter does die-cut stock, so several drawer labels are ganged onto
one sticker and you cut them apart. Same drawer labels, same 40 x 15mm
house size, different carrier.

Routes (all under /admin/labels/dymo):
    /                 choose labels, pick the stock, see the sheet
    /preview.png      one rendered sticker
    /download.pdf     the print-ready PDF, page size = the stock size

There is no direct printing here on purpose: the LabelWriter 4XL is a USB
printer, not a network one, so the PDF goes through whatever driver the
machine already has. Print at 100% / Actual size.

Created by: Jess Rogerson (yelling commands at Claude.AI)
"""

import logging

from flask import (Blueprint, abort, current_app, flash, redirect,
                   render_template, request, send_file, url_for)
from flask_login import login_required

from app.models.site_setting import SiteSetting
from app.routes.admin import admin_required
from app.routes.labels_tape import _group_spec, _selected_labels
from app.services import dymo_sheet, tape_printer

logger = logging.getLogger(__name__)

dymo_bp = Blueprint('dymo', __name__, url_prefix='/admin/labels/dymo')


def _tape_options(source):
    """What goes ON each drawer label - shared with tape printing, so a
    label looks the same whichever printer it comes off."""
    options = tape_printer.options_from_form(
        source,
        size_default=SiteSetting.get('tape_size_mode',
                                     tape_printer.DEFAULT_SIZE_MODE))
    # 'Fit the tape width' is meaningless on die-cut stock: there is no
    # tape to fit. Fall back to the house sizes.
    if not options.is_fixed:
        options.size_mode = tape_printer.DEFAULT_SIZE_MODE
    return options


def _query(sheet, options, labels, group_spec=None):
    """Every option as query args, so preview images and the PDF link show
    exactly what the page shows."""
    query = {
        'ids': ','.join(str(l.id) for l in labels),
        tape_printer.FORM_MARKER: '1',
        'stock': sheet.stock,
        'layout': sheet.layout,
        'margin_mm': sheet.margin_mm,
        'gap_mm': sheet.gap_mm,
        'start_at': sheet.start_at,
        'size_mode': options.size_mode,
        'copies': options.copies,
        'font_scale': options.font_scale,
        'image_percent': options.image_percent,
        'padding_mm': options.padding_mm,
        'align': options.align,
        'fields': options.fields,
    }
    for name, on in (('cut_guides', sheet.cut_guides),
                     ('centre', sheet.centre),
                     ('monochrome', sheet.monochrome),
                     ('group_drawers', options.group_drawers),
                     ('outline', options.outline)):
        if on:
            query[name] = '1'
    if group_spec:
        query['groups'] = group_spec
    return query


@dymo_bp.route('/', methods=['GET', 'POST'])
@login_required
@admin_required
def index():
    labels = _selected_labels()
    if not labels:
        flash('Select some labels to print first.', 'warning')
        return redirect(url_for('labels.index'))

    source = request.form if request.method == 'POST' else request.args
    options = _tape_options(source)
    sheet = dymo_sheet.sheet_options_from_form(
        source, stock_default=SiteSetting.get('dymo_stock',
                                              dymo_sheet.DEFAULT_STOCK))

    group_spec = _group_spec()
    plan = tape_printer.plan_groups(labels, options, group_spec)
    pages = dymo_sheet.plan_sheets(plan, sheet, copies=options.copies)
    per_sheet, cols, rows = dymo_sheet.capacity(sheet)

    return render_template(
        'admin/labels/dymo.html',
        labels=labels,
        plan=plan,
        pages=pages,
        ids=','.join(str(l.id) for l in labels),
        options=options,
        sheet=sheet,
        stocks=dymo_sheet.STOCKS,
        stock=dymo_sheet.get_stock(sheet.stock),
        layouts=dymo_sheet.LAYOUTS,
        size_modes=[(key, text) for key, text in tape_printer.SIZE_MODES
                    if key in tape_printer.FIXED_MODES],
        per_sheet=per_sheet,
        grid=f'{cols} across, {rows} down',
        query=_query(sheet, options, labels, group_spec),
        field_options=[
            ('image', 'Part image'), ('name', 'Part name'),
            ('dimensions', 'Dimensions'), ('part_number', 'Part number'),
            ('alt_numbers', 'Alternate numbers'), ('category', 'Category'),
            ('category_code', 'Category code'), ('location', 'Drawer'),
            ('colour', 'Colour name'), ('accent', 'Colour stripe'),
        ],
    )


def _rendered_pages():
    """The sticker images for the current request's options."""
    labels = _selected_labels()
    if not labels:
        abort(400, 'No labels selected.')
    options = _tape_options(request.args)
    sheet = dymo_sheet.sheet_options_from_form(request.args)
    plan = tape_printer.plan_groups(labels, options, _group_spec())
    return dymo_sheet.render_pages(
        plan, sheet, options, current_app.config['UPLOAD_FOLDER'],
        copies=options.copies)


@dymo_bp.route('/preview.png')
@login_required
@admin_required
def preview():
    """One sticker, scaled for the screen."""
    pages = _rendered_pages()
    index_ = request.args.get('page', type=int) or 1
    if index_ < 1 or index_ > len(pages):
        abort(404)
    return send_file(dymo_sheet.preview_png(pages[index_ - 1]),
                     mimetype='image/png')


@dymo_bp.route('/download.pdf', methods=['GET', 'POST'])
@login_required
@admin_required
def download_pdf():
    """The print-ready PDF: one page per sticker, exactly the stock size."""
    labels = _selected_labels()
    if not labels:
        flash('Nothing selected.', 'warning')
        return redirect(url_for('labels.index'))

    source = request.form if request.method == 'POST' else request.args
    options = _tape_options(source)
    sheet = dymo_sheet.sheet_options_from_form(source)
    plan = tape_printer.plan_groups(labels, options, _group_spec())

    buffer = dymo_sheet.render_pdf(
        plan, sheet, options, current_app.config['UPLOAD_FOLDER'],
        copies=options.copies)
    if buffer is None:
        flash('Nothing to render.', 'warning')
        return redirect(url_for('labels.index'))

    stock = dymo_sheet.get_stock(sheet.stock)
    # Truncated, not rounded: 101.6mm stock is sold as "101 x 54".
    name = f'lego-labels-{int(stock.width_mm)}x{int(stock.height_mm)}mm.pdf'
    return send_file(buffer, mimetype='application/pdf', as_attachment=True,
                     download_name=name)