shopdb-flask/plugins/tools/frontend/views/CodeGenerator.vue

<template>
  <div class="code-generator">
    <div class="page-header no-print">
      <h1>Barcode / QR Generator</h1>
      <div class="header-actions">
        <!-- Sends somebody THIS code, already set up. The content rides in the
             fragment, so it never reaches the server or its logs. -->
        <button class="btn btn-secondary" :disabled="!shareable" @click="copyShareLink">
          {{ sharecopied ? 'Link copied' : 'Copy share link' }}
        </button>
        <router-link to="/tools" class="btn btn-secondary">Back to Tech Tools</router-link>
      </div>
    </div>

    <div v-if="sharelink" class="share-row no-print">
      <input class="form-control mono" :value="sharelink" readonly
             @focus="$event.target.select()">
      <p class="share-note">
        Opens this page with the content and layout already set. The part after
        the <code>#</code> never reaches the server, so it stays out of the logs
        - but anyone holding the link can read it, so send a password with
        Secure Send instead.
      </p>
    </div>

    <div class="workspace">
      <div class="options no-print">
        <div class="controls card">
        <!-- What to encode -->
        <div class="control-row">
          <label>
            Source
            <select v-model="source">
              <option value="single">One code</option>
              <option value="csv">CSV list</option>
            </select>
          </label>
          <label>
            Code type
            <select v-model="codetype">
              <option value="qr">QR</option>
              <option value="barcode">CODE128</option>
              <option value="code39">CODE39</option>
            </select>
          </label>
          <label v-if="codetype === 'qr'">
            Error correction
            <select v-model="errorcorrection">
              <option value="L">L - smallest code</option>
              <option value="M">M - standard</option>
              <option value="Q">Q</option>
              <option value="H">H - most robust</option>
            </select>
          </label>
        </div>

        <div v-if="source === 'single'" class="control-row">
          <label class="grow">
            Content (text or URL)
            <textarea v-model="singleContent" rows="2"
                      placeholder="https://example.com or any text"></textarea>
          </label>
          <label class="grow">
            Label (optional)
            <input v-model="singleLabel" type="text" placeholder="Printed under or beside the code" />
          </label>
          <label>
            Copies
            <input v-model.number="singleCopies" type="number" min="1" max="1000" />
          </label>
        </div>

        <div v-else class="csv-block">
          <div class="control-row">
            <label>
              CSV file
              <input type="file" accept=".csv,text/csv" @change="onCsvFile" />
            </label>
            <button class="btn btn-secondary" @click="downloadTemplate">Download template</button>
          </div>
          <label class="grow">
            ...or paste rows here
            <textarea v-model="csvText" rows="5"
                      placeholder="content,label,copies&#10;https://example.com,Front desk,1&#10;WJ-LF-0001,Line 1,2"></textarea>
          </label>
          <p class="control-note" v-if="csvError">{{ csvError }}</p>
          <p class="control-hint">
            Columns: <code>content</code> (required), <code>label</code>, <code>copies</code><span
              v-if="backCarriesOwnContent">, <code>back</code>, <code>backlabel</code></span>.
            A header row is optional; without one the order is content, label, copies<span
              v-if="backCarriesOwnContent">, back, backlabel</span>.
          </p>
        </div>

        <!-- Media -->
        <h4 class="section-heading">Label stock</h4>
        <div class="control-row">
          <label>
            Preset
            <select v-model="preset" @change="applyPreset">
              <option value="">Custom</option>
              <option v-for="option in PRESETS" :key="option.id" :value="option.id">
                {{ option.name }}
              </option>
            </select>
          </label>
          <label>Label W (in)<input v-model.number="labelwidth" type="number" step="0.01" min="0.25" /></label>
          <label>Label H (in)<input v-model.number="labelheight" type="number" step="0.01" min="0.25" /></label>
          <label>Padding (in)<input v-model.number="padding" type="number" step="0.005" min="0" /></label>
          <label>
            Layout
            <select v-model="layout">
              <option value="side">Code left, label right</option>
              <option value="stack">Code above label</option>
              <option value="codeonly">Code only</option>
            </select>
          </label>
        </div>

        <div class="control-row">
          <label v-if="codetype === 'qr'">Code size (in)<input v-model.number="codesize" type="number" step="0.0001" min="0.1" /></label>
          <label v-else>Bar height (in)<input v-model.number="barheight" type="number" step="0.01" min="0.1" /></label>
          <label>Quiet zone (in)<input v-model.number="quiet" type="number" step="0.005" min="0" /></label>
          <label>Code-label gap (in)<input v-model.number="gap" type="number" step="0.005" min="0" /></label>
          <label>Label font (pt)<input v-model.number="labelfont" type="number" step="0.5" min="3" /></label>
        </div>

        <p class="control-hint">
          The quiet zone is the clear space the SCANNER needs and it stays wrapped
          around the code. The gap is only the space between the code and its
          caption, and it adds to the quiet zone rather than eating into it.
        </p>

        <!-- The dot-size trap: a thermal head cannot render a fraction of a dot,
             so a code sized off the dot grid gets uneven modules and scans
             badly. This says what the current size actually lands on. -->
        <div class="control-row">
          <label>
            Printer DPI
            <select v-model.number="dpi">
              <option :value="203">203</option>
              <option :value="300">300</option>
              <option :value="600">600</option>
            </select>
          </label>
          <p v-if="codetype === 'qr' && fitAdvice" class="control-hint fit-advice">
            {{ fitAdvice }}
          </p>
        </div>

        <!-- Position -->
        <h4 class="section-heading">Position</h4>
        <div class="control-row">
          <label>
            Align
            <select v-model="align">
              <option value="flex-start">Left</option>
              <option value="center">Center</option>
              <option value="flex-end">Right</option>
            </select>
          </label>
          <label>
            Vertical
            <select v-model="valign">
              <option value="flex-start">Top</option>
              <option value="center">Middle</option>
              <option value="flex-end">Bottom</option>
            </select>
          </label>
          <label>Content X (in)<input v-model.number="contentx" type="number" step="0.01" /></label>
          <label>Content Y (in)<input v-model.number="contenty" type="number" step="0.01" /></label>
          <label>Media X (in)<input v-model.number="nudgex" type="number" step="0.01" /></label>
          <label>Media Y (in)<input v-model.number="nudgey" type="number" step="0.01" /></label>
        </div>

        <p class="control-hint">
          Content moves the code and caption INSIDE the label and leaves the label
          where it is. Media moves the whole printed area on the stock - that one
          is for a printer whose origin is off, not for composing a label.
        </p>

        <!-- Picture -->
        <h4 class="section-heading">Picture</h4>
        <div class="control-row">
          <label>
            Image file
            <input type="file" accept="image/*" @change="onPictureFile" />
          </label>
          <button v-if="pictureUrl" class="btn btn-secondary" @click="clearPicture">Remove picture</button>
          <template v-if="pictureUrl">
            <label>Size (in)<input v-model.number="picturesize" type="number" step="0.01" min="0.05" /></label>
            <label>
              Where
              <select v-model="pictureposition">
                <option value="above">Above the code</option>
                <option value="beside">Beside the code</option>
                <option value="behind">Behind everything (watermark)</option>
              </select>
            </label>
            <label>
              Which side
              <select v-model="pictureside">
                <option value="front">Front only</option>
                <option value="back">Back only</option>
                <option value="both">Both sides</option>
              </select>
            </label>
            <label v-if="pictureposition === 'behind'">
              Opacity
              <input v-model.number="pictureopacity" type="number" step="0.05" min="0.05" max="1" />
            </label>
          </template>
        </div>

        <p class="control-hint">
          The picture never leaves the browser, so this works on an air-gapped
          site. It is also NOT remembered between visits, unlike the sizing -
          an image is far too big to keep in the settings the page saves.
          A watermark behind a code costs the scanner contrast: keep the opacity
          low and test a scan before printing a run.
        </p>

        <!-- Back side -->
        <h4 class="section-heading">Back side</h4>
        <div class="control-row">
          <label class="check">
            <input type="checkbox" v-model="backenabled" />
            Print a back side
          </label>
          <template v-if="backenabled">
            <label>
              Back carries
              <select v-model="backsource">
                <option value="code">The same code again</option>
                <option value="column">Its own code (per row)</option>
                <option value="text">Fixed text, no code</option>
                <option value="blank">Nothing - blank back</option>
              </select>
            </label>
            <label v-if="backCarriesCode">
              Back code type
              <select v-model="backcodetype">
                <option value="same">Same as the front</option>
                <option value="qr">QR</option>
                <option value="barcode">CODE128</option>
                <option value="code39">CODE39</option>
              </select>
            </label>
            <label>
              Back layout
              <select v-model="backlayout">
                <option value="side">Code left, label right</option>
                <option value="stack">Code above label</option>
                <option value="codeonly">Code only</option>
                <option value="textonly" :disabled="backCarriesCode">Text only, no code</option>
              </select>
            </label>
            <label>
              Page order
              <select v-model="backorder">
                <option value="interleave">Front, back, front, back (duplex printer)</option>
                <option value="grouped">All fronts, then all backs (flip and reload)</option>
              </select>
            </label>
          </template>
        </div>

        <div v-if="backenabled" class="control-row">
          <label class="grow" v-if="source === 'single' && backCarriesOwnContent">
            Back content (encoded on the back)
            <textarea v-model="singleBack" rows="2"
                      placeholder="A second code for the reverse - text or URL"></textarea>
          </label>
          <label class="grow" v-if="backsource === 'text' || backCarriesOwnContent">
            Back text
            <textarea v-model="backtext" rows="2"
                      placeholder="Property of GE Aerospace - return to IT"></textarea>
          </label>
        </div>

        <p v-if="backenabled" class="control-hint">
          <strong>Duplex printer:</strong> keep page order interleaved and set the
          driver to double-sided, flip on SHORT edge for portrait card stock -
          long edge prints the back upside down.
          <strong>Single-sided printer:</strong> choose grouped, print the run,
          flip the whole stack keeping its order, and print the second half.
          Print one card both ways before committing the box.
        </p>

        <div class="control-row">
          <button class="btn btn-primary" :disabled="!pages.length" @click="printAll">
            Print {{ cardCount }} label{{ cardCount === 1 ? '' : 's' }}
            <span v-if="backenabled">({{ pages.length }} pages)</span>
          </button>
          <button class="btn btn-secondary" :disabled="!pages.length" @click="printTest">
            Print 1 test {{ backenabled ? 'card (both sides)' : 'label' }}
          </button>
          <button class="btn btn-secondary" @click="resetSettings">Reset sizing</button>
        </div>

        <p v-if="truncated" class="control-note">
          Showing the first {{ MAX_LABELS }} labels. {{ truncated }} more were left out
          - split the CSV and print it in batches.
        </p>
        <p v-if="overlong.length" class="control-note">
          {{ overlong.length }} row(s) could not be encoded or were empty:
          {{ overlong.slice(0, 3).join(', ') }}{{ overlong.length > 3 ? ' ...' : '' }}
        </p>
        </div>
      </div>

      <!-- Preview doubles as the print surface: what is on screen is what
           prints, so everything around it is chrome that print must strip. -->
      <div class="preview">
        <div class="preview-head no-print">
          <h4 class="section-heading">Preview</h4>
          <span class="preview-count">
            {{ cardCount }} label{{ cardCount === 1 ? '' : 's' }}<span
              v-if="backenabled">, {{ pages.length }} pages</span>
          </span>
        </div>
        <div class="sheet">
        <div
          v-for="item in visible"
          :key="item.index"
          class="label"
          :class="labelClasses(item.page)"
        >
          <img v-if="showPicture(item.page) && pictureposition === 'behind'"
               :src="pictureUrl" class="picture-behind" alt="" />
          <div class="content">
            <div v-if="showPicture(item.page) && pictureposition !== 'behind'" class="picturebox">
              <img :src="pictureUrl" class="picture-img" alt="" />
            </div>
            <div class="codegroup">
              <div v-if="layoutFor(item.page) !== 'textonly'" class="codebox">
                <img v-if="images[item.index]" :src="images[item.index]" class="code-img" alt="" />
                <!-- An empty code box is indistinguishable from a label that
                     simply has no code on it, which is how a failed render
                     reads as "the barcode does not appear". Say so, on screen
                     only - the printed label must never carry this. -->
                <span v-else class="code-missing">no code</span>
              </div>
              <div v-if="layoutFor(item.page) !== 'codeonly' && item.page.label" class="label-text">
                {{ item.page.label }}
              </div>
            </div>
          </div>
          <span v-if="backenabled" class="side-flag">{{ item.page.side }}</span>
        </div>
        <p v-if="!pages.length" class="preview-empty no-print">
          Nothing to print yet - enter content above.
        </p>
        </div>
      </div>
    </div>
  </div>
</template>

<script setup>
import { ref, computed, watch, onMounted, onBeforeUnmount, nextTick } from 'vue'
import { LABEL_PRESETS, qrModuleCount, qrFit, qrSvgDataUri, barcodeSvgDataUri }
  from '@/utils/codes'
import { parseCsv, buildPages, MAX_LABELS } from '../labelPages'
import { labelVars, LABEL_VAR_NAMES } from '../labelVars'
import { buildFragment, readFragment, coerce } from '../sharelink'
import { withBase } from '@/utils/basePath'

const PRESETS = LABEL_PRESETS

const source = ref('single')
const codetype = ref('qr')
const errorcorrection = ref('M')

const singleContent = ref('')
const singleLabel = ref('')
const singleCopies = ref(1)
const singleBack = ref('')

const csvText = ref('')
const csvError = ref('')

const preset = ref('zebra1x05')
const labelwidth = ref(1.0)
const labelheight = ref(0.5)
const padding = ref(0)
const quiet = ref(0.035)
const gap = ref(0.03)
const codesize = ref(0.4286)
const barheight = ref(0.3)
const labelfont = ref(7)
const layout = ref('side')
const align = ref('center')
const valign = ref('center')
const contentx = ref(0)
const contenty = ref(0)
const nudgex = ref(0)
const nudgey = ref(0)
const dpi = ref(203)

// The image itself is deliberately NOT a saved setting: a data URL runs to
// megabytes and would blow the localStorage quota, taking every sizing value
// with it. Only how it is placed persists.
const pictureUrl = ref('')
const picturesize = ref(0.5)
const pictureposition = ref('above')
const pictureside = ref('front')
const pictureopacity = ref(0.15)

const backenabled = ref(false)
const backsource = ref('code')
const backcodetype = ref('same')
const backtext = ref('')
const backlayout = ref('stack')
const backorder = ref('interleave')

const images = ref([])
const testMode = ref(false)
const overlong = ref([])

// The values a first-time visitor starts with, captured before localStorage or
// a shared link overwrites anything. A share link then carries only what the
// sender actually changed.
const DEFAULT_SETTINGS = {}

const SETTING_KEYS = [
  'codetype', 'errorcorrection', 'preset', 'labelwidth', 'labelheight', 'padding',
  'quiet', 'gap', 'codesize', 'barheight', 'labelfont', 'layout', 'align', 'valign',
  'contentx', 'contenty', 'nudgex', 'nudgey', 'dpi',
  'picturesize', 'pictureposition', 'pictureside', 'pictureopacity',
  'backenabled', 'backsource', 'backcodetype', 'backtext', 'backlayout', 'backorder',
]
const settingRefs = {
  codetype, errorcorrection, preset, labelwidth, labelheight, padding,
  quiet, gap, codesize, barheight, labelfont, layout, align, valign,
  contentx, contenty, nudgex, nudgey, dpi,
  picturesize, pictureposition, pictureside, pictureopacity,
  backenabled, backsource, backcodetype, backtext, backlayout, backorder,
}
for (const key of SETTING_KEYS) DEFAULT_SETTINGS[key] = settingRefs[key].value

// --- back side --------------------------------------------------------------

const backCarriesCode = computed(() =>
  backsource.value === 'code' || backsource.value === 'column')

const backCarriesOwnContent = computed(() =>
  backenabled.value && backsource.value === 'column')

// A back that carries a code and a back laid out as text-only cancel each other
// out, and the result is a blank card that looks like the code failed to
// render. Keep the two honest in both directions, including for settings
// restored from a previous visit.
function reconcileBackLayout() {
  if (backCarriesCode.value && backlayout.value === 'textonly') backlayout.value = 'stack'
  if (!backCarriesCode.value && backlayout.value !== 'textonly') backlayout.value = 'textonly'
}

watch(backsource, reconcileBackLayout)

/** QR or CODE128 for this page. The back may deliberately differ from the
 *  front: a QR that opens a record, a CODE128 the bench scanner already
 *  understands. */
function codeTypeFor(page) {
  if (page.side !== 'back') return codetype.value
  return backcodetype.value === 'same' ? codetype.value : backcodetype.value
}

function layoutFor(page) {
  return page.side === 'back' ? backlayout.value : layout.value
}

function showPicture(page) {
  if (!pictureUrl.value) return false
  if (pictureside.value === 'both') return true
  return pictureside.value === page.side
}

function labelClasses(page) {
  const type = codeTypeFor(page)
  // code39 and barcode (CODE128) share the same CSS class for linear barcode layout
  const typeClass = type === 'code39' ? 'barcode' : type
  return [
    'layout-' + layoutFor(page),
    'type-' + typeClass,
    'side-' + page.side,
    showPicture(page) && pictureposition.value !== 'behind' ? 'pic-' + pictureposition.value : '',
  ]
}

// --- rows -------------------------------------------------------------------

// The rows before copies are expanded. CSV parsing and page building both live
// in ../labelPages.js, which is where they can be tested.
const rows = computed(() => {
  if (source.value === 'single') {
    const content = singleContent.value.trim()
    if (!content) return []
    const copies = Number.isFinite(singleCopies.value) && singleCopies.value > 0
      ? singleCopies.value : 1
    return [{
      content,
      label: singleLabel.value.trim(),
      copies,
      back: singleBack.value.trim(),
      backlabel: '',
    }]
  }
  try {
    csvError.value = ''
    const parsed = parseCsv(csvText.value)
    if (csvText.value.trim() && !parsed.length) {
      csvError.value = 'No usable rows found. Every row needs a content value.'
    }
    return parsed
  } catch (error) {
    csvError.value = 'Could not read that CSV: ' + error.message
    return []
  }
})

const built = computed(() => buildPages(rows.value, {
  back: {
    enabled: backenabled.value,
    source: backsource.value,
    text: backtext.value.trim(),
    order: backorder.value,
  },
  max: MAX_LABELS,
}))

const pages = computed(() => built.value.pages)
const cardCount = computed(() => built.value.fronts.length)
const truncated = computed(() => built.value.dropped)

// What the preview renders, each item carrying its index into `images`. The
// index has to travel with the page: a test print shows two of the pages and
// the rendered codes are keyed by position in the full run, so pairing them by
// loop position printed the wrong code onto the test card.
const visible = computed(() => {
  const all = pages.value.map((page, index) => ({ page, index }))
  if (!testMode.value) return all
  const { fronts, backs } = built.value
  if (!fronts.length) return []
  const items = [{ page: fronts[0], index: 0 }]
  if (backenabled.value && backs.length) {
    // Where the first back sits depends on the order the run is emitted in.
    items.push({
      page: backs[0],
      index: backorder.value === 'grouped' ? fronts.length : 1,
    })
  }
  return items
})

// --- fit advice -------------------------------------------------------------

// Modules across the QR at the current content and error correction, quiet
// zone excluded (the blank label supplies that).
const qrModules = computed(() => {
  const content = built.value.fronts[0]?.content
  if (!content || codetype.value !== 'qr') return 0
  return qrModuleCount(content, errorcorrection.value)
})

const fitAdvice = computed(() => {
  const fit = qrFit(built.value.fronts[0]?.content, {
    sizeInches: codesize.value, dpi: dpi.value, errorCorrection: errorcorrection.value,
  })
  if (!fit || codetype.value !== 'qr') return ''
  const { modules, dotsPerModule, wholeDots: whole, snapped, moduleMm } = fit
  if (fit.tooSmall) {
    return `${modules} modules at ${dotsPerModule.toFixed(2)} dots each - too small to scan `
      + `reliably. Shorten the content, drop error correction, or use bigger stock.`
  }
  if (fit.even) {
    return `${modules} modules at exactly ${whole} dots each (${moduleMm.toFixed(3)} mm). Good.`
  }
  return `${modules} modules at ${dotsPerModule.toFixed(2)} dots each. Uneven - `
    + `use ${snapped.toFixed(4)} in for a whole ${whole} dots per module.`
})

// --- rendering --------------------------------------------------------------

// Each code renders to an SVG data URI, for two reasons. An <img> prints
// reliably where a live canvas or inline SVG does not (same finding the asset
// label pages are built on), and SVG rasterizes at the printer's resolution
// with hard module edges - a PNG would be downscaled to the label size and
// smear the very edges a scanner reads.
//
// margin 0 on the QR: the quiet zone is blank label supplied by --tool-quiet,
// so none of the code box is spent on white we cannot then adjust.
async function renderOne(page) {
  const text = page.content
  if (!text) return ''
  const type = codeTypeFor(page)
  if (type === 'qr') {
    return qrSvgDataUri(text, { errorCorrection: errorcorrection.value })
  }
  if (type === 'code39') {
    return barcodeSvgDataUri(text, { format: 'CODE39' })
  }
  return barcodeSvgDataUri(text)
}

let renderToken = 0
async function renderAll() {
  const token = ++renderToken
  const failed = []
  const next = []
  for (const page of pages.value) {
    try {
      next.push(await renderOne(page))
    } catch {
      // CODE128 rejects some characters; an unencodable row must be named,
      // not silently dropped to a blank sticker.
      next.push('')
      failed.push(page.content.slice(0, 20))
    }
    if (token !== renderToken) return
  }
  images.value = next
  overlong.value = failed
}

// --- media vars -------------------------------------------------------------

// @page cannot read a scoped style, so the sizing lives in custom properties on
// the root element. Chromium honors var() in @page size.
//
// The values are built in ../labelVars.js, which is also where the rule lives
// that none of them may be NaN or empty: a cleared number field used to emit
// `NaNin`, the browser dropped the declaration, and a box that fell back to
// auto height rendered the barcode 176 wide by 0 high.
function applyVars() {
  const root = document.documentElement
  const vars = labelVars({
    labelwidth: labelwidth.value,
    labelheight: labelheight.value,
    padding: padding.value,
    codesize: codesize.value,
    barheight: barheight.value,
    // Both symbologies need clear space: a QR wants a quiet zone around it, and
    // CODE128 wants one at each end (10x the narrow bar). It is the code's own
    // margin and nothing else's - the space between the code and the caption is
    // the gap, so a tight caption no longer means shaving the quiet zone.
    quiet: quiet.value,
    gap: gap.value,
    labelfont: labelfont.value,
    align: align.value,
    valign: valign.value,
    // Content offset moves what is printed WITHIN the label. Media offset moves
    // the label box itself on the stock. They are different fixes: the first
    // composes a label, the second corrects a printer whose origin is off.
    contentx: contentx.value,
    contenty: contenty.value,
    nudgex: nudgex.value,
    nudgey: nudgey.value,
    picturesize: picturesize.value,
    pictureopacity: pictureopacity.value,
  })
  for (const [name, value] of Object.entries(vars)) root.style.setProperty(name, value)
}

function clearVars() {
  const root = document.documentElement
  for (const name of LABEL_VAR_NAMES) root.style.removeProperty(name)
}

function applyPreset() {
  const chosen = PRESETS.find(option => option.id === preset.value)
  if (!chosen) return
  labelwidth.value = chosen.labelwidth
  labelheight.value = chosen.labelheight
  codesize.value = chosen.codesize
  padding.value = chosen.padding
  quiet.value = chosen.quiet
  labelfont.value = chosen.labelfont
  if (chosen.gap !== undefined) gap.value = chosen.gap
}

function resetSettings() {
  preset.value = 'zebra1x05'
  applyPreset()
  layout.value = 'side'
  barheight.value = 0.3
  align.value = 'center'
  valign.value = 'center'
  contentx.value = 0
  contenty.value = 0
  nudgex.value = 0
  nudgey.value = 0
}

// --- picture ----------------------------------------------------------------

function onPictureFile(event) {
  const file = event.target.files && event.target.files[0]
  if (!file) return
  const reader = new FileReader()
  reader.onload = () => { pictureUrl.value = String(reader.result || '') }
  reader.onerror = () => { pictureUrl.value = '' }
  reader.readAsDataURL(file)
}

function clearPicture() {
  pictureUrl.value = ''
}

// --- csv helpers ------------------------------------------------------------

function onCsvFile(event) {
  const file = event.target.files && event.target.files[0]
  if (!file) return
  const reader = new FileReader()
  reader.onload = () => { csvText.value = String(reader.result || '') }
  reader.onerror = () => { csvError.value = 'Could not read that file.' }
  reader.readAsText(file)
}

function downloadTemplate() {
  // The template carries the back columns only when they would be read, so a
  // one-sided run is not handed a CSV with two columns it must ignore.
  const csv = backCarriesOwnContent.value
    ? [
      'content,label,copies,back,backlabel',
      'https://example.com/asset/1,Bay 12 press,1,https://example.com/asset/1/history,Service history',
      'WJ-LF-0001,Line 1 fixture,2,WJ-LF-0001-B,Return to Tool Crib',
    ].join('\n')
    : [
      'content,label,copies',
      'https://example.com/asset/1,Bay 12 press,1',
      'WJ-LF-0001,Line 1 fixture,2',
    ].join('\n')
  const link = document.createElement('a')
  link.href = URL.createObjectURL(new Blob([csv], { type: 'text/csv' }))
  link.download = 'code_labels_template.csv'
  link.click()
  URL.revokeObjectURL(link.href)
}

// --- printing ---------------------------------------------------------------

function printAll() {
  window.print()
}

async function printTest() {
  testMode.value = true
  await nextTick()
  window.print()
  testMode.value = false
}

// --- lifecycle --------------------------------------------------------------

function saveSettings() {
  const state = {}
  for (const key of SETTING_KEYS) state[key] = settingRefs[key].value
  try { localStorage.setItem('toolsCodeGenerator', JSON.stringify(state)) } catch { /* private mode */ }
}

// ---------------------------------------------------------------- sharing ---
//
// A link that opens this page with the work already in it. Everything rides in
// the fragment, which is never sent to the server - see ../sharelink.js.

const sharelink = ref('')
const sharecopied = ref(false)

// What travels: the typed content and every layout value. The picture does not
// - a data URL runs to megabytes and no chat client would carry the link.
function shareState () {
  const state = {
    source: source.value,
    content: singleContent.value,
    label: singleLabel.value,
    copies: singleCopies.value,
    back: singleBack.value,
    csv: source.value === 'csv' ? csvText.value : '',
  }
  for (const key of SETTING_KEYS) state[key] = settingRefs[key].value
  return state
}

const shareable = computed(() =>
  Boolean(source.value === 'csv' ? csvText.value.trim() : singleContent.value.trim()))

function makeShareLink () {
  // Defaults are what a first-time visitor starts with, so only the values
  // somebody actually changed end up in the link.
  const fragment = buildFragment(shareState(), DEFAULT_SETTINGS)
  const mount = withBase('/').replace(/\/+$/, '')
  sharelink.value = `${window.location.origin}${mount}/tools/codes${fragment}`
}

async function copyShareLink () {
  makeShareLink()
  try {
    await navigator.clipboard.writeText(sharelink.value)
    sharecopied.value = true
    setTimeout(() => { sharecopied.value = false }, 2000)
  } catch {
    // Clipboard refused (http, or a locked-down browser). The box below still
    // holds the link to copy by hand, which is why it is rendered at all.
  }
}

onMounted(() => {
  try {
    const saved = JSON.parse(localStorage.getItem('toolsCodeGenerator') || '{}')
    for (const key of SETTING_KEYS) {
      if (saved[key] !== undefined) settingRefs[key].value = saved[key]
    }
  } catch { /* ignore a corrupt entry */ }

  // A shared link wins over this browser's saved settings: somebody following
  // one is asking to see THAT code, not their own last one.
  const shared = readFragment(window.location.hash)
  if (Object.keys(shared).length) {
    if (shared.source) source.value = shared.source === 'csv' ? 'csv' : 'single'
    if (shared.content !== undefined) singleContent.value = shared.content
    if (shared.label !== undefined) singleLabel.value = shared.label
    if (shared.copies !== undefined) singleCopies.value = coerce(shared.copies, singleCopies.value)
    if (shared.back !== undefined) singleBack.value = shared.back
    if (shared.csv) { csvText.value = shared.csv; source.value = 'csv' }
    for (const key of SETTING_KEYS) {
      if (shared[key] !== undefined) {
        settingRefs[key].value = coerce(shared[key], settingRefs[key].value)
      }
    }
  }

  reconcileBackLayout()
  applyVars()
  renderAll()
})

onBeforeUnmount(clearVars)

watch(SETTING_KEYS.map(key => settingRefs[key]), () => {
  applyVars()
  saveSettings()
})

watch([pages, codetype, backcodetype, errorcorrection], renderAll)
</script>

<style scoped>
/* One page per side. Chromium reads var() here; the print dialog must be set
   to Margins = None and Scale = 100%. */
@page { size: var(--tool-label-w, 1in) var(--tool-label-h, 0.5in); margin: 0; }

.code-generator { width: 100%; }

.header-actions { display: flex; gap: 0.5rem; align-items: center; }

/* Full width and monospace: the link is long, and somebody copying it by hand
   needs to see where it ends. */
.share-row { margin: 0 0 1rem; }
.share-row .mono {
  font-family: Consolas, monospace;
  font-size: 0.85rem;
  width: 100%;
}
.share-note {
  margin: 0.35rem 0 0;
  font-size: 0.85rem;
  color: var(--text-light);
}

/* Settings on the left, the labels themselves on the right, where they stay in
   view while the settings that change them are being worked. The preview
   column scrolls on its own so a 500-label run cannot push the controls off
   the screen. */
.workspace {
  display: grid;
  grid-template-columns: minmax(0, 3fr) minmax(300px, 2fr);
  gap: 20px;
  align-items: start;
}

.preview {
  position: sticky;
  top: 12px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 16px 16px;
  max-height: calc(100vh - var(--main-pad-top) - 24px);
  overflow: auto;
}

.preview-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
}

.preview-head .section-heading { margin-top: 0.25rem; }

.preview-count { font-size: 0.8125rem; color: var(--text-light); }

.preview-empty { color: var(--text-light); font-size: 0.8125rem; margin: 0; }

/* One column once the two would be too narrow to work in. */
@media (max-width: 1200px) {
  .workspace { grid-template-columns: minmax(0, 1fr); }
  .preview { position: static; max-height: none; }
}

.controls {
  background: var(--bg-card);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 20px;
}

.section-heading {
  margin: 1.25rem 0 0.5rem;
  font-size: 0.9rem;
  color: var(--text-light);
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.control-row {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  align-items: flex-end;
  margin-bottom: 12px;
}

.control-row label {
  display: flex;
  flex-direction: column;
  font-size: 0.8125rem;
  gap: 4px;
  color: var(--text-light);
}

.control-row label.grow { flex: 1 1 18rem; }

.control-row label.check {
  flex-direction: row;
  align-items: center;
  gap: 6px;
  padding-bottom: 6px;
}

.control-row input,
.control-row select,
.control-row textarea,
.csv-block input,
.csv-block textarea {
  padding: 6px;
  font-size: 0.875rem;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 4px;
  font-family: inherit;
}

.control-row label.check input[type="checkbox"] { width: auto; }

.control-row input[type="number"] { width: 7rem; }

.csv-block label {
  display: flex;
  flex-direction: column;
  font-size: 0.8125rem;
  gap: 4px;
  color: var(--text-light);
}

.control-note { color: var(--warning); font-size: 0.8125rem; margin: 8px 0 0; }
.control-hint { color: var(--text-light); font-size: 0.8125rem; margin: 8px 0 12px; }
.fit-advice { flex: 1 1 22rem; align-self: center; }

.sheet {
  padding: 20px 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* The label is the MEDIA. It never moves for composition reasons - only the
   media offset moves it, and that exists for a printer whose origin is off. */
.label {
  box-sizing: border-box;
  width: var(--tool-label-w, 1in);
  height: var(--tool-label-h, 0.5in);
  padding: var(--tool-pad, 0);
  background: #fff;
  color: #000;
  overflow: hidden;
  display: flex;
  justify-content: var(--tool-align, center);
  align-items: var(--tool-valign, center);
  position: relative;
  left: var(--tool-nudge-x);
  top: var(--tool-nudge-y);
  outline: 1px dashed var(--border);
}

/* Everything printed sits in here, so it can be aligned and nudged as one
   block without the label box following it off the stock. No max-width or
   max-height: overflow must CLIP against the label, the way it did before this
   wrapper existed. Constrain it and the flex children shrink instead, and the
   one that gives way is the barcode - it is the only box allowed to flex. */
.content {
  display: flex;
  align-items: center;
  gap: var(--tool-gap, 0.03in);
  position: relative;
  z-index: 1;
  transform: translate(var(--tool-content-x, 0), var(--tool-content-y, 0));
}

/* The code and its caption, which is the group a picture sits above or beside. */
.codegroup {
  display: flex;
  align-items: center;
  gap: var(--tool-gap, 0.03in);
}

.label.layout-stack .codegroup { flex-direction: column; justify-content: center; }

.label.pic-above .content { flex-direction: column; }
.label.pic-beside .content { flex-direction: row; }

/* A CODE128 wants the width, so its block takes the label rather than sitting
   in the middle of it. */
.label.type-barcode .content,
.label.type-barcode .codegroup { width: 100%; }

.picturebox {
  flex: 0 0 auto;
  width: var(--tool-pic, 0.5in);
  height: var(--tool-pic, 0.5in);
  display: flex;
  align-items: center;
  justify-content: center;
}

.picture-img {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
}

/* A watermark sits under the code, not in it, and only as dark as the setting
   says - a scanner reads contrast, and this is the control that costs it. */
.picture-behind {
  position: absolute;
  top: 50%;
  left: 50%;
  width: var(--tool-pic);
  height: var(--tool-pic);
  transform: translate(-50%, -50%);
  object-fit: contain;
  opacity: var(--tool-pic-opacity, 0.15);
  z-index: 0;
}

.codebox {
  flex: 0 0 auto;
  margin: var(--tool-quiet, 0.035in);
  width: var(--tool-code, 0.43in);
  height: var(--tool-code, 0.43in);
  display: flex;
  align-items: center;
  justify-content: center;
}

/* A QR is square, so its box is code-size on a side. A CODE128 is wide and
   short: it takes the width left over on the label and only its own bar
   height, or the whole width when nothing shares the label with it. */
.label.type-barcode .codebox {
  flex: 1 1 auto;
  width: auto;
  /* Never below 40% of the label: past that a CODE128 is too few narrow bars
     to scan, so it is better for the caption to wrap or clip. */
  min-width: 40%;
  height: var(--tool-barh, 0.3in);
}

.label.layout-stack.type-barcode .codebox { min-width: 100%; }

/* Screen-only, and deliberately loud: an empty box means the render failed. */
.code-missing {
  font-family: Arial, Helvetica, sans-serif;
  font-size: 6px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--danger);
}

.code-img {
  width: 100%;
  height: 100%;
  object-fit: contain;
}

/* The caption takes what it needs and no more. Both boxes used to grow, so a
   caption of any length halved the barcode and then kept going - at 1x0.5in
   with a couple of words it left a 36px stub that reads as "the code did not
   render". A code that cannot be scanned is not a label. */
.label-text {
  flex: 0 1 auto;
  min-width: 0;
  text-align: center;
  font-family: "Arial Narrow", Arial, Helvetica, sans-serif;
  font-size: var(--tool-font, 7pt);
  font-weight: 700;
  line-height: 1.05;
  overflow-wrap: anywhere;
}

/* Which side you are looking at, on screen only. A two-sided run is a wall of
   near-identical rectangles otherwise. */
.side-flag {
  position: absolute;
  top: 2px;
  right: 3px;
  font-size: 7px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text-light);
  z-index: 2;
}

.label.side-back { outline-style: dotted; }

@media print {
  .side-flag { display: none !important; }
  .code-missing { display: none !important; }
  .sheet { padding: 0; display: block; gap: 0; }
  /* The preview column is chrome. Its overflow matters most: a scrolling
     ancestor clips a multi-page print to whatever was on screen. */
  .workspace { display: block; }
  .preview {
    position: static;
    max-height: none;
    overflow: visible;
    border: 0;
    border-radius: 0;
    padding: 0;
    background: none;
  }
  /* The back's dotted variant outspecifies a bare .label reset, so it printed
     a dashed rule down the edge of every second card. */
  .label,
  .label.side-back {
    outline: none;
    break-after: page;
    page-break-after: always;
  }
  .label:last-of-type { break-after: auto; page-break-after: auto; }
}
</style>