nameplate-model.js

// Nameplates: equipment nameplate OCR checked against the equipment schedule.
// On a data centre job the gear is the job (UPS, PDUs, switchgear, gensets,
// CRAHs, chillers), and the costly mistakes are a unit delivered at the wrong
// voltage or rating, or one that never gets onto the asset register. This
// module turns OCR text into nameplate fields, matches a reading to the
// schedule, checks each field, and builds the register CSV.
//
// OCR is Tesseract.js (pretrained, loaded from the CDN like the other models),
// so nothing here is trained: it is parsing and matching.
// Pure functions (tests/nameplate-model.test.mjs).
import { parseCsv } from './schedule-import.js';

export const FIELDS = [
  // Identification.
  ['manufacturer', 'Manufacturer', 'id'], ['model', 'Model', 'id'], ['serial', 'Serial', 'id'], ['mfgDate', 'Mfg date', 'id'],
  // Electrical.
  ['voltage', 'Voltage', 'electrical'], ['phase', 'Phase', 'electrical'], ['hz', 'Hz', 'electrical'],
  ['kva', 'kVA', 'electrical'], ['kw', 'kW', 'electrical'], ['amps', 'Amps', 'electrical'], ['pf', 'Power factor', 'electrical'],
  ['mca', 'MCA', 'electrical'], ['mocp', 'MOCP', 'electrical'], ['sccr', 'SCCR (kA)', 'electrical'],
  ['enclosure', 'Enclosure', 'electrical'], ['standards', 'Listings', 'electrical'], ['batteryType', 'Battery type', 'electrical'],
  ['batteryAh', 'Battery Ah', 'electrical'], ['cells', 'Battery cells', 'electrical'],
  // Cooling.
  ['refrigerant', 'Refrigerant', 'cooling'], ['charge', 'Refrigerant charge', 'cooling'], ['tons', 'Cooling (tons)', 'cooling'],
  ['btu', 'Cooling (BTU/h)', 'cooling'], ['cfm', 'Airflow (CFM)', 'cooling'], ['gpm', 'Flow (GPM)', 'cooling'],
  // Server racks and IT.
  ['uHeight', 'Rack U', 'rack'], ['powerW', 'Power (W)', 'rack'], ['outlets', 'PDU outlets', 'rack'], ['ports', 'Ports', 'rack'],
  // Mechanical.
  ['rpm', 'Speed (RPM)', 'mechanical'], ['weight', 'Weight (kg)', 'mechanical'],
];

// Field groups for the reading panel; keys match the third element of FIELDS.
export const FIELD_GROUPS = [['id', 'Identification'], ['electrical', 'Electrical'], ['cooling', 'Cooling'], ['rack', 'Server racks / IT'], ['mechanical', 'Mechanical']];

// Data centre equipment types. Order is the whole game: the first pattern that
// matches a plate wins, so device-specific wording comes before the families it
// belongs to (flywheel before UPS, paralleling gear before generator, heat pump
// and pumps before the cooling families, metering before transformer, controls
// before racks).
export const EQUIPMENT_TYPES = [
  // Power conversion and transfer.
  ['flywheel', 'Flywheel UPS', /FLYWHEEL/],
  ['ups', 'UPS', /\bUPS\b|UNINTERRUPTIBLE/],
  ['sts', 'Static transfer switch', /STATIC TRANSFER|STATIC BYPASS|\bSTS\b|RACK[-\s]?ATS/],
  ['ats', 'Automatic transfer switch', /TRANSFER SWITCH|\bATS\b|\bATSE\b/],
  ['rectifier', 'Rectifier / DC power', /RECTIFIER|BATTERY CHARGER|DC POWER SYSTEM/],
  ['inverter', 'Inverter', /\bINVERTER\b|POWER CONVERSION SYSTEM/],
  ['bess', 'Battery energy storage', /BATTERY ENERGY STORAGE|\bBESS\b|ENERGY STORAGE/],
  // Prime power and distribution.
  ['nitrogen', 'Nitrogen generator', /NITROGEN GENERATOR|\bN2\s?GENERATOR\b/],
  ['paralleling', 'Paralleling gear', /PARALLELING|GENERATOR CONTROL|SYNCHRONIS|BUS TIE/],
  ['generator', 'Generator', /GENERATOR|GENSET|\bEKW\b|STANDBY POWER|PRIME POWER|DIESEL ENGINE/],
  ['fueltank', 'Fuel system', /FUEL TANK|DAY TANK|DIESEL TANK|FUEL OIL|FUEL POLISH|BULK FUEL/],
  ['switchgear', 'Switchgear / switchboard', /SWITCHGEAR|SWITCHBOARD|DISTRIBUTION BOARD|\bMDP\b|MAIN DISTRIBUTION/],
  ['mcc', 'Motor control centre', /MOTOR CONTROL|\bMCC\b/],
  ['metering', 'Metering / CT cabinet', /METERING|POWER METER|KWH METER|ELECTRIC METER|CT CABINET/],
  ['relay', 'Protective relay', /PROTECTIVE RELAY|PROTECTION RELAY|FEEDER RELAY|POWER SYSTEM RELAY|\bANSI\s?(?:50|51|27|59|81|87)\b/],
  ['tmonitor', 'Transformer / DGA monitor', /TRANSFORMER MONITOR|DISSOLVED GAS|\bDGA\b|TRANSFORMER MONITORING/],
  ['transformer', 'Transformer', /TRANSFORMER|\bXFMR\b|PRIMARY.*SECONDARY|DRY TYPE|ISOLATION TRANSFORMER|K[-\s]?RATED/],
  ['spd', 'Surge protection', /SURGE PROTECT|\bSPD\b|\bTVSS\b|TRANSIENT VOLTAGE/],
  ['capacitor', 'Power factor / filter', /CAPACITOR|POWER FACTOR|HARMONIC FILTER|\bPFC\b/],
  ['ngr', 'Neutral grounding resistor', /NEUTRAL GROUNDING|GROUNDING RESISTOR|\bNGR\b/],
  ['vfd', 'Variable frequency drive', /VARIABLE FREQUENCY|VARIABLE SPEED|\bVFD\b|\bVSD\b|\bAFD\b/],
  ['busway', 'Busway', /BUSWAY|BUS PLUG|BUS DUCT|ISOLATED PHASE BUS|PHASE BUS/],
  ['panelboard', 'Panelboard', /PANELBOARD|PANEL BOARD|LOAD CENTER/],
  ['pdu', 'PDU / RPP', /POWER DISTRIBUTION UNIT|\bPDU\b|\bRPP\b|REMOTE POWER PANEL/],
  ['battery', 'Battery / battery cabinet', /\bBATTERY\b|VRLA|LITHIUM|LEAD ACID/],
  ['loadbank', 'Load bank', /LOAD BANK|LOADBANK|RESISTIVE LOAD/],
  // Pumps come before the cooling families: a "condenser water pump" or a
  // "chilled water pump" is a pump, not the machine it serves; "heat pump" is
  // matched first so the compressor word inside it does not win.
  ['heatpump', 'Heat pump', /HEAT PUMP/],
  ['pump', 'Pump', /\bPUMP\b/],
  // Cooling and mechanical.
  ['coolingtower', 'Cooling tower', /COOLING TOWER|COOLING TWR|EVAPORATIVE CONDENSER/],
  ['thermalstorage', 'Thermal storage', /THERMAL STORAGE|CHILLED WATER STORAGE|ICE STORAGE/],
  ['chiller', 'Chiller', /\bCHILLER\b/],
  ['condenser', 'Dry cooler / condenser', /DRY COOLER|FLUID COOLER|EVAPORATIVE COOLER|REMOTE CONDENSER|AIR[-\s]?COOLED CONDENSER|ADIABATIC|CONDENSER/],
  ['cdu', 'CDU / liquid cooling', /COOLANT DISTRIBUTION|\bCDU\b|LIQUID COOLING|IMMERSION|DIRECT TO CHIP|COOLANT MANIFOLD|REAR DOOR/],
  ['crah', 'CRAH / CRAC', /\bCRAH\b|\bCRAC\b|COMPUTER ROOM AIR/],
  ['ahu', 'Air handling unit', /\bAHU\b|AIR HANDLING|AIR HANDLER/],
  ['heatexchanger', 'Heat exchanger', /HEAT EXCHANGER|PLATE HEAT|PLATE AND FRAME/],
  ['expansiontank', 'Expansion tank', /EXPANSION TANK|HYDROPNEUMATIC/],
  ['airseparator', 'Air separator', /AIR SEPARATOR|AIR SEPARATION|\bAIR SCOOP\b/],
  ['boiler', 'Boiler', /\bBOILER\b/],
  ['humidifier', 'Humidifier / dehumidifier', /HUMIDIFIER|HUMIDIFICATION|DEHUMIDIFIER/],
  ['watertreatment', 'Water treatment', /WATER TREATMENT|WATER SOFTENER|REVERSE OSMOSIS|\bRO SYSTEM\b|CHEMICAL DOSING|SIDE STREAM FILTER|SAND FILTER|CARBON FILTER|WATER FILTER/],
  ['dryer', 'Air dryer', /AIR DRYER|DESICCANT|REFRIGERATED DRYER/],
  ['compressor', 'Compressor', /\bCOMPRESSOR\b/],
  ['fcu', 'Fan coil / fan wall', /\bFCU\b|FAN COIL|FAN WALL|EXHAUST FAN|SUPPLY FAN|RETURN FAN/],
  ['rtu', 'Rooftop unit', /ROOFTOP UNIT|\bRTU\b|PACKAGED UNIT|PACKAGE UNIT/],
  ['mua', 'Makeup air unit', /MAKEUP AIR|MAKE-UP AIR|\bMUA\b/],
  ['economizer', 'Economizer', /ECONOMIZER/],
  // Fire, safety and controls.
  ['firesuppression', 'Fire suppression', /FIRE SUPPRESSION|CLEAN AGENT|\bFM[-\s]?200\b|NOVEC|INERT GAS|SPRINKLER|PRE[-\s]?ACTION|\bCO2\b|AEROSOL/],
  ['firealarm', 'Fire alarm', /FIRE ALARM|\bVESDA\b|SMOKE DETECT|ASPIRATING|HEAT DETECT/],
  ['leakdetection', 'Leak / gas detection', /LEAK DETECT|WATER DETECT|REFRIGERANT MONITOR|GAS DETECT/],
  ['bms', 'BMS / controls', /\bBMS\b|\bEPMS\b|\bDCIM\b|BUILDING MANAGEMENT|\bBAS\b|CONTROL PANEL|CONTROL CABINET|\bPLC\b|CONTROLLER/],
  // IT and white space. Rack before server so "server rack / enclosure" is a
  // rack; KVM before server so "console server" is a console.
  ['kvm', 'KVM / console', /\bKVM\b|CONSOLE SERVER/],
  ['rack', 'Rack / enclosure', /EQUIPMENT RACK|\bRACK\b|ENCLOSURE|\bCABINET\b/],
  ['server', 'Server / storage', /\bSERVER\b|BLADE|STORAGE ARRAY|\bSAN\b|\bNAS\b|HCI NODE/],
  ['network', 'Network gear', /NETWORK SWITCH|ETHERNET SWITCH|\bROUTER\b|PATCH PANEL|FIREWALL|LOAD BALANCER/],
];

// Makers common on data centre electrical, cooling, IT and fire packages.
// Matched as whole words; anything else falls back to a line that reads like a
// company. Longer names precede the shorter names they contain.
const MAKERS = [
  'Schneider Electric', 'Square D', 'APC', 'Eaton', 'ABB', 'Siemens', 'Vertiv', 'Liebert', 'Caterpillar', 'Cummins',
  'Kohler', 'Rolls-Royce Power Systems', 'Rolls-Royce', 'MTU', 'Generac', 'Trane', 'Carrier', 'Daikin', 'York',
  'Johnson Controls', 'Stulz', 'Munters', 'nVent', 'Legrand', 'Mitsubishi Electric', 'Toshiba', 'General Electric',
  'Hubbell', 'Socomec', 'Piller', 'Starline', 'Raritan', 'Server Technology', 'Emerson', 'Russelectric', 'ASCO',
  'Hitachi', 'Riello', 'Rittal', 'Motivair', 'CoolIT', 'Hitec', 'EnerSys', 'Leclanché', 'Samsung SDI',
  // Cooling and mechanical.
  'Airedale', 'Uniflair', 'Climaveneta', 'Aermec', 'FläktGroup', 'FlaktGroup', 'Systemair', 'ebm-papst', 'Danfoss',
  'Grundfos', 'Wilo', 'Xylem', 'Bell & Gossett', 'Armstrong', 'Taco', 'Flowserve', 'SPX', 'Baltimore Aircoil',
  'Evapco', 'Marley', 'LU-VE', 'Alfa Laval', 'SWEP', 'Tranter', 'Boyd', 'Asetek',
  // Power distribution, switchgear and batteries.
  'PDI', 'Power Distribution Inc', 'Anord Mardix', 'Mardix', 'Universal Electric', 'Hammond', 'Hoffman',
  'Exide', 'C&D Technologies', 'GS Yuasa', 'FIAMM', 'NorthStar', 'Saft', 'Hoppecke', 'LG Energy', 'CATL', 'Fluence',
  'Aggreko', 'Himoinsa', 'Perkins', 'Volvo Penta', 'Deutz', 'Wartsila',
  // IT and network.
  'Dell', 'HPE', 'Hewlett Packard', 'Cisco', 'Juniper', 'Arista', 'Lenovo', 'Supermicro', 'IBM', 'Fujitsu', 'NetApp',
  'Pure Storage', 'Aten', 'Avocent',
  // Fire, detection and controls.
  'Fike', 'Kidde', 'Tyco', 'Viking', 'Victaulic', 'Hochiki', 'Xtralis', 'VESDA', 'Notifier', 'Honeywell',
  'Delta Controls', 'Distech', 'Automated Logic', 'Tridium',
];
const COMPANY_LINE = /\b(INC|CORP|CORPORATION|LTD|LLC|GMBH|CO\.|COMPANY|SYSTEMS|ELECTRIC|POWER|TECHNOLOGIES|INDUSTRIES|ENGINEERING|INTERNATIONAL|GROUP|AG|SA|BV|NV|PTY|WORKS|THERMAL|CONTROLS|SOLUTIONS|MANUFACTURING)\b/;

const NUM = '(\\d{1,5}(?:[.,]\\d+)?)';
// "1,002" is a thousands separator on a US plate; "2,5" is a European decimal.
const num = s => (s == null ? null : parseFloat(/^\d{1,3},\d{3}$/.test(String(s)) ? String(s).replace(',', '') : String(s).replace(',', '.')));
// Range guards: a rating of 0, or an absurd value, is an OCR artefact, not a field.
const positive = v => (typeof v === 'number' && Number.isFinite(v) && v > 0 ? v : null);
const inRange = (v, lo, hi) => (typeof v === 'number' && Number.isFinite(v) && v >= lo && v <= hi ? v : null);

/**
 * Nameplate fields from OCR output: a string, or lines as [{ text, confidence }]
 * (Tesseract's data.lines). Each field is { value, conf } (conf 0–100, the OCR
 * confidence of the line it came from; 100 for plain text).
 */
export function parseNameplate(input) {
  const lines = (typeof input === 'string' ? input.split(/\r?\n/).map(text => ({ text, confidence: 100 })) : input)
    .map(l => ({ text: ocrFix(String(l.text || '').replace(/\s+/g, ' ').trim()), conf: Math.round(l.confidence ?? 100), bbox: l.bbox || null }))
    // Lines Tesseract itself scores near zero are texture read as text (brushed metal, a busy background).
    .filter(l => l.text && l.conf >= 20);
  const fields = {};
  // line: index of the OCR line the value came from, so the page can outline it on the photo.
  const set = (key, value, conf, line) => { if (fields[key] == null && value != null && value !== '') fields[key] = { value, conf, line }; };
  // Each rule runs over every line in order, so the first line that has the field wins.
  const scan = (key, re, map = m => m[1]) => {
    for (const [i, l] of lines.entries()) {
      const m = up(l.text).match(re);
      if (m) { const v = map(m); if (v != null && v !== '') { set(key, v, l.conf, i); return; } }
    }
  };

  const CODE = '([A-Z0-9][A-Z0-9\\-\\/\\.]{2,})';
  scan('model', new RegExp(`(?:\\bMODEL\\b|\\bMOD\\.|\\bM\\/N\\b|\\bCAT(?:ALOG)?\\.?\\s*(?:NO\\b\\.?|#|NUMBER)|\\bP\\/N\\b|\\bPART\\s*(?:NO\\b\\.?|#|NUMBER))\\s*(?:NO\\b\\.?|NUMBER\\b|#)?\\s*[:#.]?\\s*${CODE}`), m => cleanCode(m[1]));
  scan('serial', new RegExp(`(?:\\bSERIAL\\b|\\bSER\\.|\\bS\\/N\\b|\\b5\\/N\\b|\\bSN\\b)\\s*(?:NO\\b\\.?|NUMBER\\b|#)?\\s*[:#.]?\\s*([A-Z0-9][A-Z0-9\\-]{3,})`), m => cleanCode(m[1]));
  scan('refrigerant', /\bR[-\s]?(410A|134A|1234ZE|1234YF|1233ZD|513A|514A|515B|454B|468A|449A|407C|452A|455A|245FA|123|32|22|717|744|290|128|503|508B)\b/, m => `R-${m[1]}`);
  scan('hz', /\b(50|60)\s*HZ\b|\bHZ\s*[:]?\s*(50|60)\b|\bFREQ(?:UENCY)?\.?\s*[:]?\s*(50|60)\b/, m => +(m[1] || m[2] || m[3]));
  scan('phase', /\b([13])\s*-?\s*(?:PH|PHASE|Ø|Φ)\b|\bPH(?:ASE)?\s*[:]?\s*([13])\b/, m => +(m[1] || m[2]));
  scan('kva', new RegExp(`${NUM}\\s*KVA\\b|\\bKVA\\s*[:]?\\s*${NUM}`), m => positive(num(m[1] || m[2])));
  scan('kw', new RegExp(`${NUM}\\s*E?KW\\b|\\bE?KW\\s*[:]?\\s*${NUM}`), m => positive(num(m[1] || m[2])));
  scan('mfgDate', /\b(?:MFG\.?|MANUFACTURED|MFD\.?|BUILD|PROD(?:UCTION)?\.?)\s*(?:DATE)?\s*[:]?\s*(\d{1,2}[/-]\d{2,4}|\d{4}[/-]\d{1,2}(?:[/-]\d{1,2})?|\d{1,2}[/-]\d{1,2}[/-]\d{2,4})/, m => m[1]);

  // Voltage: every voltage on the plate (a transformer or UPS carries more than one).
  const volts = [];
  let voltLine = null;
  for (const [i, l] of lines.entries()) {
    const found = voltagesIn(up(l.text));
    if (found.values.length) {
      for (const v of found.values) if (!volts.includes(v)) volts.push(v);
      if (!voltLine) voltLine = { text: found.display, conf: l.conf, line: i };
    }
  }
  if (volts.length) fields.voltage = { value: voltLine.text, conf: voltLine.conf, line: voltLine.line, values: volts };

  // Amps: a labelled rated current first, then any bare "1002 A". Refrigerants (R-410A) are not amps.
  scan('amps', new RegExp(`(?:\\bFLA\\b|\\bRLA\\b|\\bCURRENT\\b|\\bAMPS?\\b|\\bAMPERES\\b)\\s*[:]?\\s*${NUM}`), m => positive(num(m[1])));
  if (!fields.amps) scan('amps', new RegExp(`(?<![-\\d.R])${NUM}\\s*(?:A|AMPS?)\\b`), m => positive(num(m[1])));
  scan('mca', new RegExp(`\\bMCA\\b\\s*[:]?\\s*${NUM}`), m => positive(num(m[1])));
  scan('mocp', new RegExp(`(?:\\bMOCP\\b|\\bMAX\\.?\\s*(?:FUSE|BREAKER|OCP))\\s*(?:SIZE)?\\s*[:]?\\s*${NUM}`), m => positive(num(m[1])));

  // Data centre electrical: power factor and short-circuit/interrupting rating.
  scan('pf', /(?:POWER\s*FACTOR|\bP\.?F\b)\s*[:=]?\s*(0?[.,]\d{1,3}|1(?:[.,]0+)?)\b|(0?[.,]\d{1,3})\s*P\.?F\b/, m => inRange(num(m[1] || m[2]), 0.01, 1));
  scan('sccr', new RegExp(`${NUM}\\s*KAIC\\b|(?:\\bSCCR\\b|SHORT[\\s-]?CIRCUIT|WITHSTAND|INTERRUPTING RATING|\\bKAIC\\b)[^0-9]{0,12}${NUM}\\s*(?:KA|K)?\\b`), m => inRange(num(m[1] || m[2]), 0.1, 1000));

  // Enclosure rating: NEMA type or IEC IP code.
  scan('enclosure', /\bNEMA\s*(?:TYPE\s*)?(\d{1,2}[A-Z]?)\b|\bIP\s*(\d{2}[A-Z]{0,2})\b/, m => (m[1] ? `NEMA ${m[1]}` : `IP ${m[2]}`));

  // Mechanical / cooling nameplates: refrigerant charge, capacity, airflow and flow.
  scan('charge', new RegExp(`CHARGE\\s*(?:WEIGHT)?\\s*[:]?\\s*${NUM}\\s*(?:LBS?|KG|KGS?|OZ)?\\b`), m => positive(num(m[1])));
  scan('tons', new RegExp(`${NUM}\\s*TONS?\\b|\\bTONS?\\s*[:]?\\s*${NUM}`), m => positive(num(m[1] || m[2])));
  scan('btu', new RegExp(`${NUM}\\s*(?:BTU\\/?H?R?|BTUH)\\b|\\bBTU\\/?H?R?\\s*[:]?\\s*${NUM}`), m => positive(num(m[1] || m[2])));
  scan('cfm', new RegExp(`${NUM}\\s*CFM\\b|\\bCFM\\s*[:]?\\s*${NUM}`), m => positive(num(m[1] || m[2])));
  scan('gpm', new RegExp(`${NUM}\\s*(?:GPM|LPM|L\\/S|M3\\/H)\\b|\\bGPM\\s*[:]?\\s*${NUM}`), m => positive(num(m[1] || m[2])));
  scan('batteryAh', new RegExp(`${NUM}\\s*(?:AH|AMP[\\s-]?HOURS?)\\b`), m => positive(num(m[1])));

  // Battery chemistry, cell count, rotating speed, rigging weight and listing marks.
  scan('batteryType', /\b(VRLA|AGM|GEL|FLOODED|LITHIUM[-\s]?ION|LI[-\s]?ION|LIFEPO4|NICD|NI[-\s]?CD|LEAD[-\s]?ACID|NICKEL[-\s]?CADMIUM|VALVE[-\s]?REGULATED)\b/, m => batteryTypeName(m[1]));
  scan('cells', new RegExp(`(?:CELLS?|CELL\\s*COUNT)\\s*[:]?\\s*${NUM}\\b|${NUM}\\s*CELLS?\\b`), m => inRange(num(m[1] || m[2]), 1, 1000));
  scan('rpm', new RegExp(`${NUM}\\s*RPM\\b|\\bRPM\\s*[:]?\\s*${NUM}`), m => inRange(num(m[1] || m[2]), 1, 200000));
  scan('weight', new RegExp(`(?:WEIGHT|NET\\s?WEIGHT|NET\\s?WT|MASS)\\s*[:]?\\s*${NUM}\\s*(LBS?|LB|KGS?|KG|TONS?)?\\b`), m => positive(weightKg(num(m[1]), m[2])));
  scan('standards', /\b(UL\s?\d{3,5}[A-Z]?|IEC\s?\d{4,5}|ANSI\s?[A-Z]{1,3}[-\s]?\d{1,4}|IEEE\s?\d{1,4}|NFPA\s?\d{1,3}|CSA\s?[A-Z]?\d{1,4}|EN\s?\d{4,5})\b/, m => m[1].replace(/\s+/g, ' ').trim());

  // Server racks: rack-unit height, IT power draw, PDU outlets and network ports.
  scan('uHeight', /\b(\d{1,2})\s*U\b/, m => { const v = +m[1]; return v >= 1 && v <= 60 ? v : null; });
  scan('powerW', new RegExp(`(?:POWER|INPUT POWER|RATED POWER)\\s*[:]?\\s*${NUM}\\s*W\\b|(?<![KE])${NUM}\\s*W\\b`), m => positive(num(m[1] || m[2])));
  scan('outlets', new RegExp(`${NUM}\\s*(?:OUTLETS?|RECEPTACLES?)\\b|\\bOUTLETS?\\s*[:]?\\s*${NUM}`), m => inRange(num(m[1] || m[2]), 1, 10000));
  scan('ports', new RegExp(`\\b(\\d{1,3})\\s*-?\\s*PORTS?\\b|\\bPORTS?\\s*[:]?\\s*${NUM}`), m => inRange(num(m[1] || m[2]), 1, 10000));

  // Manufacturer: a known maker anywhere, else a line that reads like a company name.
  let makerLine = -1;
  for (const [i, l] of lines.entries()) {
    // "New York" on a supplier's address is not York the maker.
    const t = up(l.text).replace(/NEW YORK/g, '');
    const maker = MAKERS.find(mk => new RegExp(`\\b${escapeRe(up(mk))}\\b`).test(t));
    if (maker) { set('manufacturer', maker, l.conf, i); makerLine = i; break; }
  }
  if (!fields.manufacturer) {
    const i = lines.findIndex(x => COMPANY_LINE.test(up(x.text)) && !/\d{3}/.test(x.text) && x.text.length <= 48);
    if (i >= 0) { set('manufacturer', titleCase(lines[i].text.replace(/[^A-Za-z0-9&.,\- ]/g, '').trim()), lines[i].conf, i); makerLine = i; }
  }

  // Equipment type from plate text, excluding the maker line: a vendor called
  // "…Transformer Corp" or "…Switchgear Ltd" must not type a chiller plate.
  const all = up(lines.filter((_, i) => i !== makerLine).map(l => l.text).join('\n'));
  const type = (EQUIPMENT_TYPES.find(([, , re]) => re.test(all)) || [null])[0];
  const conf = lines.length ? Math.round(lines.reduce((s, l) => s + l.conf, 0) / lines.length) : 0;
  return { fields, type, conf, text: lines.map(l => l.text).join('\n'), lines: lines.map(l => ({ text: l.text, conf: l.conf, bbox: l.bbox })) };
}

/**
 * Undo the misreads Tesseract makes on plate lettering (seen in tests/nameplates-bench.mjs):
 * a serifed "V" read as "Vv", "Y" as "¥", codes and decimals split after their punctuation
 * ("NPX- 750- 480", "38. 5"), "HZ" as "Hw"/"H2", "KVA" as "XVA".
 */
export function ocrFix(t) {
  return t
    .replace(/[¥]/g, 'Y')
    .replace(/[‘’`]/g, "'")
    .replace(/(\d)\s*V[vV]\b/g, '$1 V')
    .replace(/([A-Za-z0-9])-\s+(?=[A-Za-z0-9])/g, '$1-')
    .replace(/(\d)\.\s+(?=\d)/g, '$1.')
    .replace(/\b(50|60)\s*H[wW2]\b/g, '$1 HZ')
    // K read as X in KVA / KW / EKW.
    .replace(/(\d\s*)XVA\b/g, '$1KVA')
    .replace(/(\d\s*)E[KX][WN]\b/g, '$1EKW')
    .replace(/(\d\s*)XW\b/g, '$1KW');
}

/** Voltages written on one line: 480Y/277V, 208/120 VAC, VOLTS: 480, 13.8 kV. */
export function voltagesIn(s) {
  s = s.replace(/(\d),(\d{3})\b/g, '$1$2');   // 13,800 V
  const values = [];
  let display = null;
  const add = (v, shown) => {
    if (!(v >= 100 && v <= 40000)) return;
    if (!values.includes(v)) values.push(v);
    if (!display) display = shown;
  };
  const pair = /\b(\d{3,5})\s*(Y)?\s*\/\s*(\d{3,5})\s*(?:V|VAC|VOLTS?)?\b/g;
  let m;
  const isLabelled = /VOLT|\bV\b|\bVAC\b|\dV\b/.test(s);
  while ((m = pair.exec(s))) {
    // "480/277" with no V anywhere on the line could be anything; require a voltage word or unit.
    if (!isLabelled && !/\d\s*(?:V|VAC|VOLTS?)\b/.test(m[0])) continue;
    add(+m[1], `${m[1]}${m[2] ? 'Y' : ''}/${m[3]} V`);
    add(+m[3], null);
  }
  const single = /\b(\d{3,5})\s*(?:V|VAC|VDC|VOLTS?)\b/g;
  while ((m = single.exec(s))) add(+m[1], `${m[1]} V`);
  const labelled = /\bVOLT(?:S|AGE)?\b[^0-9]{0,12}(\d{3,5})\b/g;
  while ((m = labelled.exec(s))) add(+m[1], `${m[1]} V`);
  const kv = /\b(\d{1,2}(?:\.\d{1,2})?)\s*KV\b/g;
  while ((m = kv.exec(s))) add(Math.round(parseFloat(m[1]) * 1000), `${m[1]} kV`);
  return { values, display };
}

// ------------------------------------------------------------------ schedule

const HEADERS = {
  tag: /^(tag|mark|equipment tag|equip(ment)? (id|no\.?|number|tag)|asset( tag| id)?|id|unit tag)$/i,
  type: /^(type|equipment|equipment type|description|desc|item|system)$/i,
  manufacturer: /^(manufacturer|mfr\.?|mfg\.?|make|brand|vendor|basis of design)$/i,
  model: /^(model|model no\.?|model number|model #|cat(alog)? no\.?|catalog number|part (no\.?|number))$/i,
  serial: /^(serial|serial no\.?|serial number|s\/n)$/i,
  voltage: /^(voltage|volts|v|input voltage|volts\/phase|electrical)$/i,
  phase: /^(phase|ph|phases)$/i,
  kva: /^(kva|rating \(kva\)|kva rating|capacity \(kva\))$/i,
  kw: /^(kw|ekw|rating \(kw\)|kw rating|capacity \(kw\))$/i,
  amps: /^(amps|a|amperage|fla|rated current|current)$/i,
  pf: /^(pf|power factor)$/i,
  mca: /^(mca|min\.? circuit amp(s|acity)?|minimum circuit ampacity)$/i,
  mocp: /^(mocp|max\.? (fuse|breaker|ocp)( size)?|maximum overcurrent protection)$/i,
  sccr: /^(sccr|short.?circuit|withstand|interrupting rating|kaic)$/i,
  enclosure: /^(enclosure|nema|nema type|ip rating|enclosure type)$/i,
  standards: /^(standards?|listings?|approvals?|compliance|ul|iec|ansi)$/i,
  batteryType: /^(battery type|battery technology|battery chemistry|cell type)$/i,
  refrigerant: /^(refrigerant|ref\.?)$/i,
  charge: /^(charge|refrigerant charge|charge (lbs|kg))$/i,
  tons: /^(tons|tonnage|cooling \(tons\)|cooling tons|refrigeration tons|tr)$/i,
  btu: /^(btu|btuh|btu\/h|cooling \(btu\/?h\)|cooling btu)$/i,
  cfm: /^(cfm|airflow|air flow|air volume)$/i,
  gpm: /^(gpm|flow|water flow|flow rate)$/i,
  batteryAh: /^(ah|amp.?hours?|battery ah|battery capacity)$/i,
  cells: /^(cells?|cell count|battery cells)$/i,
  rpm: /^(rpm|speed|rated speed|r\/min)$/i,
  weight: /^(weight|net weight|mass|wt|weight \(kg\))$/i,
  uHeight: /^(u|u height|rack u|ru|height \(u\)|u size)$/i,
  powerW: /^(power|power \(w\)|watts?|w|rated power|input power)$/i,
  outlets: /^(outlets?|receptacles?|pdu outlets?|outlet count)$/i,
  ports: /^(ports?|port count|network ports?)$/i,
  location: /^(location|room|area|level|space|served from|zone)$/i,
};

/** Equipment schedule from a CSV export: the header row is the first that names a tag or model column plus one more. */
export function parseEquipmentSchedule(text) {
  const rows = parseCsv(String(text || ''));
  const known = r => Object.values(HEADERS).filter(re => r.some(c => re.test(c.trim()))).length;
  const headerIdx = rows.findIndex(r => (r.some(c => HEADERS.tag.test(c.trim())) || r.some(c => HEADERS.model.test(c.trim()))) && known(r) >= 2);
  if (headerIdx < 0) return { items: [], problems: ['No header row with a Tag or Model column was found.'] };
  const header = rows[headerIdx].map(c => c.trim());
  const cols = Object.fromEntries(Object.keys(HEADERS).map(k => [k, header.findIndex(h => HEADERS[k].test(h))]));
  const items = [], problems = [];
  rows.slice(headerIdx + 1).forEach((r, i) => {
    const get = k => (cols[k] >= 0 ? String(r[cols[k]] ?? '').trim() : '');
    const tag = get('tag') || (get('model') ? `Row ${headerIdx + i + 2}` : '');
    if (!tag) return;
    if (items.some(x => x.tag === tag)) problems.push(`Tag ${tag} appears more than once; the first row is used.`);
    else items.push({
      tag, type: get('type'), manufacturer: get('manufacturer'), model: get('model'), serial: get('serial'),
      voltage: get('voltage'), phase: num(get('phase').match(/[13]/)?.[0]), kva: num(get('kva')) || null, kw: num(get('kw')) || null,
      amps: num(get('amps')) || null, pf: num(get('pf')) || null, mca: num(get('mca')) || null, mocp: num(get('mocp')) || null,
      sccr: num(get('sccr')) || null, enclosure: get('enclosure'), standards: get('standards'), batteryType: get('batteryType'),
      refrigerant: get('refrigerant'), charge: num(get('charge')) || null, tons: num(get('tons')) || null, btu: num(get('btu')) || null,
      cfm: num(get('cfm')) || null, gpm: num(get('gpm')) || null, batteryAh: num(get('batteryAh')) || null,
      cells: num(get('cells')) || null, rpm: num(get('rpm')) || null, weight: num(get('weight')) || null,
      uHeight: num(get('uHeight')) || null, powerW: num(get('powerW')) || null,
      outlets: num(get('outlets')) || null, ports: num(get('ports')) || null, location: get('location'),
    });
  });
  if (!items.length) problems.push('The header was found but no equipment rows under it.');
  return { items, problems };
}

/** Voltages a schedule cell asks for: "480Y/277", "480V 3PH", "13.8kV". */
export function scheduleVoltages(cell) {
  const s = up(cell);
  const r = voltagesIn(s);
  if (r.values.length) return r.values;
  return [...s.matchAll(/(?<![\d.])(\d{3,5})(?![\d.])/g)].map(m => +m[1]).filter(v => v >= 100 && v <= 40000);
}

// ------------------------------------------------------------------ matching

/** Model/serial codes compared the way OCR gets them wrong: O/0, I/L/1, S/5, B/8, Z/2, punctuation and case ignored. */
export function foldCode(s) {
  return up(s).replace(/[^A-Z0-9]/g, '').replace(/O/g, '0').replace(/[IL]/g, '1').replace(/S/g, '5').replace(/B/g, '8').replace(/Z/g, '2');
}

export function codeSimilarity(a, b) {
  const x = foldCode(a), y = foldCode(b);
  if (!x || !y) return 0;
  if (x === y) return 1;
  // Plate models often carry option suffixes the schedule leaves off (9395P-750 vs 9395P-750-N-480).
  const [short, long] = x.length <= y.length ? [x, y] : [y, x];
  if (short.length >= 5 && long.startsWith(short)) return 0.92;
  return 1 - levenshtein(x, y) / Math.max(x.length, y.length);
}

const sameMaker = (a, b) => {
  const x = up(a).replace(/[^A-Z0-9]/g, ''), y = up(b).replace(/[^A-Z0-9]/g, '');
  return !!x && !!y && (x.includes(y) || y.includes(x));
};

/**
 * Schedule rows this reading could be, best first: [{ item, score, registered }].
 * Data halls repeat, so several tags often share one model (UPS-1A, UPS-1B…):
 * among equal scores, tags not on the register yet come first.
 */
export function candidatesFor(reading, items, register = []) {
  const f = reading.fields || {};
  const taken = new Set(register.map(r => r.tag).filter(Boolean));
  const out = [];
  for (const item of items) {
    let score;
    if (item.serial && f.serial?.value && foldCode(item.serial) === foldCode(f.serial.value)) score = 1.5;
    else {
      const m = item.model && f.model?.value ? codeSimilarity(item.model, f.model.value) : 0;
      const mk = item.manufacturer && f.manufacturer?.value ? (sameMaker(item.manufacturer, f.manufacturer.value) ? 1 : 0) : 0.5;
      const ty = reading.type && item.type ? (typeOf(item.type) === reading.type ? 1 : 0) : 0.5;
      score = 0.7 * m + 0.15 * mk + 0.15 * ty;
      // A compatible voltage is a positive signal; mismatched voltages are only a
      // tie-breaker, so a UPS plate still prefers a UPS row over a same-voltage PDU.
      if (voltageCompatible(item, reading)) score += 0.1;
    }
    if (score >= 0.5) out.push({ item, score: Math.round(score * 100) / 100, registered: taken.has(item.tag) });
  }
  return out.sort((a, b) => (b.score - a.score) || (a.registered - b.registered));
}

/** True when the schedule row and the plate share at least one voltage. */
function voltageCompatible(item, reading) {
  if (!item.voltage) return false;
  const want = scheduleVoltages(item.voltage);
  const have = reading.fields?.voltage?.values || [];
  return want.length > 0 && have.length > 0 && want.some(v => have.includes(v));
}

/** Equipment type key for free text such as a schedule's description column. */
export function typeOf(text) {
  const s = up(text);
  return (EQUIPMENT_TYPES.find(([, , re]) => re.test(s)) || [null])[0];
}

/**
 * Field-by-field check of a reading against one schedule row:
 * [{ key, label, status: 'ok' | 'mismatch' | 'unread', expected, found }].
 * Fields the schedule leaves blank are not checked.
 */
export function checkAgainst(reading, item) {
  const f = reading.fields || {};
  const out = [];
  const push = (key, expected, found, ok) => out.push({
    key, label: FIELDS.find(x => x[0] === key)?.[1] || key, expected: String(expected), found: found == null ? '' : String(found),
    status: found == null || found === '' ? 'unread' : ok ? 'ok' : 'mismatch',
  });
  if (item.manufacturer) push('manufacturer', item.manufacturer, f.manufacturer?.value, sameMaker(item.manufacturer, f.manufacturer?.value));
  if (item.model) push('model', item.model, f.model?.value, codeSimilarity(item.model, f.model?.value) >= 0.85);
  if (item.serial) push('serial', item.serial, f.serial?.value, foldCode(item.serial) === foldCode(f.serial?.value));
  if (item.voltage) {
    const want = scheduleVoltages(item.voltage);
    const have = f.voltage?.values || (f.voltage?.value ? scheduleVoltages(f.voltage.value) : []);
    push('voltage', item.voltage, f.voltage?.value, want.length > 0 && want.every(v => have.includes(v)));
  }
  if (item.phase) push('phase', item.phase, f.phase?.value, +item.phase === +f.phase?.value);
  if (item.pf) push('pf', item.pf, f.pf?.value, Math.abs(+f.pf?.value - item.pf) <= 0.02);
  for (const k of ['kva', 'kw', 'amps', 'mca', 'mocp', 'sccr', 'charge', 'tons', 'btu', 'cfm', 'gpm', 'batteryAh', 'cells', 'rpm', 'weight', 'uHeight', 'powerW', 'outlets', 'ports']) {
    if (item[k]) push(k, item[k], f[k]?.value, Math.abs(+f[k]?.value - item[k]) <= Math.max(0.5, item[k] * 0.01));
  }
  if (item.enclosure) push('enclosure', item.enclosure, f.enclosure?.value, enclosureMatch(item.enclosure, f.enclosure?.value));
  if (item.batteryType) push('batteryType', item.batteryType, f.batteryType?.value, looseEq(item.batteryType, f.batteryType?.value));
  if (item.standards) push('standards', item.standards, f.standards?.value, looseEq(item.standards, f.standards?.value));
  if (item.refrigerant) push('refrigerant', item.refrigerant, f.refrigerant?.value, up(item.refrigerant).replace(/[^A-Z0-9]/g, '') === up(f.refrigerant?.value).replace(/[^A-Z0-9]/g, ''));
  return out;
}

/** Two short strings equal ignoring case, punctuation and spacing ("IP55" vs "IP 55"). */
function looseEq(a, b) {
  const norm = s => up(s).replace(/[^A-Z0-9]/g, '');
  const x = norm(a), y = norm(b);
  return !!x && !!y && (x === y || x.includes(y) || y.includes(x));
}

/** "NEMA 3R" vs "3R", "IP55" vs "IP 55": compare the rating code, ignoring the label. */
function enclosureMatch(a, b) {
  const norm = s => up(s).replace(/\bNEMA\b|\bTYPE\b|\bIP\b/g, '').replace(/[^A-Z0-9]/g, '');
  const x = norm(a), y = norm(b);
  return !!x && !!y && (x === y || x.includes(y) || y.includes(x));
}

/** Overall status of a register entry: matched and clean, matched with a problem, or not on the schedule. */
export function statusOf(checks, tag) {
  if (!tag) return 'unmatched';
  if (checks.some(c => c.status === 'mismatch')) return 'mismatch';
  if (checks.some(c => c.status === 'unread')) return 'partial';
  return 'verified';
}

export const STATUS_LABELS = { verified: 'Verified', partial: 'Matched, fields unread', mismatch: 'Does not match schedule', unmatched: 'Not on schedule', missing: 'Not scanned yet' };

/** Register entries that share a serial (the same plate scanned twice, or a copied serial). */
export function duplicateSerials(register) {
  const seen = new Map();
  for (const r of register) {
    const s = foldCode(r.fields?.serial?.value);
    if (!s) continue;
    seen.set(s, [...(seen.get(s) || []), r.id]);
  }
  return [...seen.values()].filter(ids => ids.length > 1);
}

/** Progress against the schedule: scanned, verified, flagged, not scanned. */
export function registerSummary(register, items = []) {
  const tags = new Set(register.map(r => r.tag).filter(Boolean));
  return {
    scanned: register.length,
    scheduled: items.length,
    scannedOfSchedule: items.filter(i => tags.has(i.tag)).length,
    verified: register.filter(r => r.status === 'verified').length,
    flagged: register.filter(r => r.status === 'mismatch').length,
    unmatched: register.filter(r => r.status === 'unmatched').length,
    duplicates: duplicateSerials(register).length,
    missing: items.filter(i => !tags.has(i.tag)).map(i => i.tag),
  };
}

/** Asset register CSV: one row per scanned plate, then every scheduled tag not scanned yet. */
export function registerCsv(register, items = []) {
  const head = ['Tag', 'Status', 'Type', 'Location', 'Manufacturer', 'Model', 'Serial', 'Voltage', 'Phase', 'Hz', 'kVA', 'kW',
    'Amps', 'PF', 'MCA', 'MOCP', 'SCCR', 'Enclosure', 'Listings', 'Battery type', 'Battery Ah', 'Battery cells',
    'Refrigerant', 'Charge', 'Cooling (tons)', 'Cooling (BTU/h)', 'Airflow (CFM)', 'Flow (GPM)', 'Speed (RPM)',
    'Weight (kg)', 'Rack U', 'Power (W)', 'Outlets', 'Ports', 'Mfg date', 'Issues', 'Scanned'];
  const byTag = new Map(items.map(i => [i.tag, i]));
  const typeLabel = k => (EQUIPMENT_TYPES.find(t => t[0] === k) || [])[1] || '';
  const dups = new Set(duplicateSerials(register).flat());
  const rows = register.map(r => {
    const f = r.fields || {};
    const v = k => f[k]?.value ?? '';
    const issues = (r.checks || []).filter(c => c.status === 'mismatch').map(c => `${c.label}: schedule ${c.expected}, plate ${c.found}`);
    if (dups.has(r.id)) issues.push('Serial also on another scanned plate');
    return [r.tag || '', STATUS_LABELS[r.status] || r.status, typeLabel(r.type), byTag.get(r.tag)?.location || '',
      v('manufacturer'), v('model'), v('serial'), v('voltage'), v('phase'), v('hz'), v('kva'), v('kw'), v('amps'), v('pf'),
      v('mca'), v('mocp'), v('sccr'), v('enclosure'), v('standards'), v('batteryType'), v('batteryAh'), v('cells'),
      v('refrigerant'), v('charge'), v('tons'), v('btu'), v('cfm'), v('gpm'), v('rpm'), v('weight'), v('uHeight'), v('powerW'), v('outlets'), v('ports'), v('mfgDate'),
      issues.join('; '), r.scannedAt ? new Date(r.scannedAt).toISOString().slice(0, 16).replace('T', ' ') : ''];
  });
  const tags = new Set(register.map(r => r.tag));
  for (const i of items) {
    if (tags.has(i.tag)) continue;
    rows.push([i.tag, STATUS_LABELS.missing, i.type, i.location, i.manufacturer, i.model, i.serial, i.voltage, i.phase ?? '',
      '', i.kva ?? '', i.kw ?? '', i.amps ?? '', i.pf ?? '', i.mca ?? '', i.mocp ?? '', i.sccr ?? '', i.enclosure ?? '',
      i.standards ?? '', i.batteryType ?? '', i.batteryAh ?? '', i.cells ?? '', i.refrigerant, i.charge ?? '', i.tons ?? '',
      i.btu ?? '', i.cfm ?? '', i.gpm ?? '', i.rpm ?? '', i.weight ?? '', i.uHeight ?? '', i.powerW ?? '', i.outlets ?? '',
      i.ports ?? '', '', '', '']);
  }
  return [head, ...rows].map(r => r.map(csvCell).join(',')).join('\n') + '\n';
}

// ------------------------------------------------------------------ sample data

// Fictional maker and models: the sample shows the workflow without implying
// any real product's ratings.
export const SAMPLE_SCHEDULE = `Tag,Description,Manufacturer,Model,Voltage,Phase,kVA,kW,MCA,MOCP,Refrigerant,Location
UPS-1A,Static UPS module,Northline Power Systems,NPX-750-480,480Y/277,3,750,675,,,,Electrical Room 1A
UPS-1B,Static UPS module,Northline Power Systems,NPX-750-480,480Y/277,3,750,675,,,,Electrical Room 1B
UPS-2A,Static UPS module,Northline Power Systems,NPX-750-480,480Y/277,3,750,675,,,,Electrical Room 2A
UPS-2B,Static UPS module,Northline Power Systems,NPX-750-480,480Y/277,3,750,675,,,,Electrical Room 2B
PDU-1-01,Power distribution unit,Northline Power Systems,NPD-300-415,480 / 415Y/240,3,300,,,,,Data Hall 1
PDU-1-02,Power distribution unit,Northline Power Systems,NPD-300-415,480 / 415Y/240,3,300,,,,,Data Hall 1
GEN-01,Diesel generator,Harbor Engine Works,HG-3000,13800,3,3750,3000,,,,Generator Yard
GEN-02,Diesel generator,Harbor Engine Works,HG-3000,13800,3,3750,3000,,,,Generator Yard
CRAH-1-01,Computer room air handler,Coldline Systems,CW-150-480,480,3,,,45,60,,Data Hall 1
CH-01,Air-cooled chiller,Coldline Systems,AC-1200,460,3,,,612,800,R-513A,Roof
`;

/** The two sample plates: one that matches UPS-1A, one delivered at the wrong voltage. */
export const SAMPLE_PLATES = [
  ['NORTHLINE POWER SYSTEMS', 'UNINTERRUPTIBLE POWER SUPPLY', 'MODEL NO: NPX-750-480', 'SERIAL NO: NL26A01937',
    'INPUT: 480Y/277 VAC  3 PH  60 HZ', 'RATING: 750 KVA / 675 KW', 'INPUT CURRENT: 1002 A', 'MFG DATE: 03/2026'],
  ['NORTHLINE POWER SYSTEMS', 'UNINTERRUPTIBLE POWER SUPPLY', 'MODEL NO: NPX-750-415', 'SERIAL NO: NL26A02210',
    'INPUT: 415Y/240 VAC  3 PH  50 HZ', 'RATING: 750 KVA / 675 KW', 'INPUT CURRENT: 1160 A', 'MFG DATE: 04/2026'],
  // A few more data centre plates so the sample shows the wider equipment set.
  ['IRONSIDE SWITCHGEAR CORP', 'SWITCHBOARD', 'MODEL NO: IS-4000-MDP', 'SERIAL NO: IS26C01188',
    '480Y/277 V  3 PH  60 HZ', '1000 KVA  MAIN BUS', 'SCCR 65 KAIC', 'NEMA 3R  MFG DATE: 05/2026'],
  ['COLDLINE SYSTEMS', 'COMPUTER ROOM AIR HANDLER', 'MODEL NO: CW-150-480', 'SERIAL NO: CL6600172',
    '480 V  3 PH  60 HZ', 'FLA 38.5  MCA 45  MOCP 60', 'AIRFLOW 12000 CFM', 'MFG DATE: 01/2026'],
  ['HARBOR ENGINE WORKS INC', 'DIESEL GENERATOR SET', 'MODEL: HG-3000', 'S/N: HEW0098812',
    '13.8 KV  3 PHASE  60 HZ', '3750 KVA  3000 EKW', '0.8 PF', 'BUILD DATE 2026-01'],
  ['POLARIS THERMAL', 'COOLING TOWER', 'MODEL NO: PT-CT-900', 'SERIAL NO: PT26D00417',
    '460 V  3 PH  60 HZ', 'MCA 86  MOCP 110', 'FLOW 2400 GPM', 'MFG DATE: 07/2026'],
  ['DELL EMC', 'POWEREDGE R650 SERVER', 'MODEL NO: R650-2U', 'SERIAL NO: DL26R00442',
    '480 V  3 PH  60 HZ', '800 W  12.5 A', 'AIRFLOW 120 CFM', 'MFG DATE: 06/2026'],
  ['VERTIV', 'RACK PDU', 'MODEL NO: MPX-30-C13', 'SERIAL NO: VR26P00117',
    '400 V  3 PH  60 HZ', '30 A  5.5 KW', '24 OUTLETS', 'MFG DATE: 08/2026'],
];

// ------------------------------------------------------------------ helpers

function up(s) { return String(s ?? '').toUpperCase(); }
function escapeRe(s) { return s.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); }
function cleanCode(s) { return s.replace(/[.\-/]+$/, ''); }
function titleCase(s) { return s.toLowerCase().replace(/\b[a-z]/g, c => c.toUpperCase()); }
/** Canonical battery chemistry from the many ways plates spell it. */
function batteryTypeName(s) {
  const t = up(s).replace(/\s+/g, ' ');
  if (/LIFEPO4/.test(t)) return 'LiFePO4';
  if (/LITHIUM|LI[-\s]?ION/.test(t)) return 'Lithium-ion';
  if (/NICD|NICKEL/.test(t)) return 'NiCd';
  if (/LEAD/.test(t)) return 'Lead-acid';
  if (/VRLA|VALVE/.test(t)) return 'VRLA';
  if (/AGM/.test(t)) return 'AGM';
  if (/GEL/.test(t)) return 'Gel';
  if (/FLOODED/.test(t)) return 'Flooded';
  return titleCase(s);
}
/** Weight normalised to kilograms so a lb plate and a kg schedule compare. */
function weightKg(v, unit) {
  if (v == null) return null;
  const u = up(unit || 'KG');
  if (/^LB/.test(u)) return Math.round(v * 0.45359237 * 10) / 10;
  if (/^TON/.test(u)) return Math.round(v * 907.18474 * 10) / 10;
  return v;
}
function csvCell(v) { const s = String(v ?? ''); return /[",\n]/.test(s) ? `"${s.replace(/"/g, '""')}"` : s; }

export function levenshtein(a, b) {
  const prev = Array.from({ length: b.length + 1 }, (_, i) => i);
  for (let i = 1; i <= a.length; i++) {
    let diag = prev[0];
    prev[0] = i;
    for (let j = 1; j <= b.length; j++) {
      const tmp = prev[j];
      prev[j] = Math.min(prev[j] + 1, prev[j - 1] + 1, diag + (a[i - 1] === b[j - 1] ? 0 : 1));
      diag = tmp;
    }
  }
  return prev[b.length];
}