tools.js

/**
 * carAgent tools — 6 tools for used-car dealers and buyers.
 * All data sources are free public APIs (NHTSA); no keys required.
 */

const NHTSA_VIN = 'https://vpic.nhtsa.dot.gov/api/vehicles/decodevin';
const NHTSA_RECALLS = 'https://api.nhtsa.gov/recalls/recallsByVin';

/** 1. vin_decode — decode VIN via NHTSA VPIC (free). */
export async function vinDecode(vin) {
  const res = await fetch(`${NHTSA_VIN}/${encodeURIComponent(vin)}?format=json`);
  const data = await res.json();
  const results = (data.Results || []).filter((r) => r.Value && r.Value !== '0' && r.Value !== 'Not Applicable');
  const pick = (name) => (results.find((r) => r.Variable === name) || {}).Value || '';
  return {
    vin,
    year: pick('Model Year'),
    make: pick('Make'),
    model: pick('Model'),
    trim: pick('Trim'),
    bodyClass: pick('Body Class'),
    driveType: pick('Drive Type'),
    fuelType: pick('Fuel Type - Primary'),
  };
}

/** 2. check_recalls — recall campaigns by VIN. */
export async function checkRecalls(vin) {
  const res = await fetch(`${NHTSA_RECALLS}?vin=${encodeURIComponent(vin)}`);
  const data = await res.json();
  const campaigns = (data.results || []).map((c) => ({
    campaignNumber: c.NHTSACampaignNumber || c.CampaignNumber || '',
    component: c.Component || '',
    summary: (c.Summary || '').slice(0, 200),
    consequence: (c.Consequence || '').slice(0, 200),
  }));
  return { vin, count: campaigns.length, campaigns };
}

/** 3. inspect_listing — extract structured fields from a listing text. */
export function inspectListing(text) {
  const s = String(text);
  const year = s.match(/\b(19|20)\d{2}\b/);
  // $ first; otherwise a 4-7 digit number that is not a year and not mileage
  const price =
    s.match(/\$\s?(\d{1,3}(?:,\d{3}){1,2})/) ||
    s.match(/\b(\d{1,3}(?:,\d{3}){1,2})\b(?!\s?(?:mi|miles|km|kms))/);
  const mileage = s.match(/([\d,]{2,7})\s?(mi|miles|km|kms)\b/i);
  const cleanTitle = s.match(/\bclean title\b/i);
  const accident = s.match(/\b(accident|salvage|rebuilt|flood)\b/i);
  return {
    year: year ? Number(year[0]) : null,
    priceUsd: price ? Number(price[1].replace(/,/g, '')) : null,
    mileage: mileage ? Number(mileage[1].replace(/,/g, '')) : null,
    mileageUnit: mileage ? mileage[2] : null,
    cleanTitle: Boolean(cleanTitle),
    flags: accident ? [accident[1].toLowerCase()] : [],
  };
}

/** 4. compare_quotes — quote comparison: min / avg / suggested offer. */
export function compareQuotes(quotes) {
  if (!Array.isArray(quotes) || quotes.length === 0) {
    return { ok: false, reason: 'no quotes' };
  }
  const prices = quotes.map((q) => q.price).filter((p) => Number.isFinite(p));
  if (prices.length === 0) return { ok: false, reason: 'no valid prices' };
  const min = Math.min(...prices);
  const avg = prices.reduce((a, b) => a + b, 0) / prices.length;
  return {
    ok: true,
    count: prices.length,
    min,
    avg: Math.round(avg),
    suggestedOffer: Math.round(min * 0.97), // 3% below best comparable
    spreadPct: Math.round(((Math.max(...prices) - min) / min) * 100),
  };
}

/** Simplified state sales tax rates (percent). */
const STATE_TAX = {
  TX: 6.25, CA: 7.25, NY: 4.0, FL: 6.0, WA: 6.5, CO: 2.9,
  AZ: 5.6, NV: 6.85, OR: 0, IL: 6.25, GA: 4.0, OH: 5.75,
};

/** 5. state_cost_calculator — out-the-door estimate. */
export function stateCostCalculator(price, state, options = {}) {
  const st = String(state || '').toUpperCase();
  const taxRate = STATE_TAX[st];
  if (taxRate === undefined) {
    return { ok: false, reason: `unknown state: ${st}` };
  }
  const docFee = options.docFee ?? 150;
  const titleFee = options.titleFee ?? 33;
  const salesTax = Math.round(price * (taxRate / 100));
  const total = price + salesTax + docFee + titleFee;
  return {
    ok: true,
    state: st,
    taxRate,
    salesTax,
    docFee,
    titleFee,
    total,
    outTheDoor: total,
  };
}

/** Common repair items with rough parts+labor estimates (USD). */
const REPAIR_BASE = {
  brake_pads: 300, brake_rotors: 500, oil_change: 80,
  battery: 200, alternator: 600, starter: 450, tires_set: 800,
  spark_plugs: 250, ac_recharge: 220, wheel_alignment: 120,
  timing_belt: 900, water_pump: 650,
};

/** 6. estimate_repairs — rough repair estimate from item list. */
export function estimateRepairs(items, options = {}) {
  const list = Array.isArray(items) ? items : [];
  const laborRate = options.laborRate ?? 120; // per hour
  const breakdown = list.map((item) => {
    const key = String(item.item || '').toLowerCase().replace(/\s+/g, '_');
    const base = REPAIR_BASE[key];
    if (base === undefined) {
      return { item: item.item, known: false, estimate: null };
    }
    const laborHrs = options.laborHrs?.[key] ?? Math.max(1, Math.round((base * 0.4) / laborRate));
    return {
      item: item.item,
      known: true,
      parts: Math.round(base * 0.6),
      labor: laborHrs * laborRate,
      laborHrs,
      estimate: Math.round(base * 0.6 + laborHrs * laborRate),
    };
  });
  const known = breakdown.filter((b) => b.known);
  const total = known.reduce((a, b) => a + b.estimate, 0);
  return { ok: true, breakdown, knownItems: known.length, total };
}

export default {
  vinDecode, checkRecalls, inspectListing,
  compareQuotes, stateCostCalculator, estimateRepairs,
};