Fix AI quote blast rate: single formula path, correct client preview

Root cause: company-settings-lookups.js had its own baseByCfm/multiplier
tables that were completely different from ShopCapabilityCalculator.cs,
so the UI showed an inflated rate (e.g. 82 sqft/hr) while the AI prompt
received the server-computed rate (e.g. 9 sqft/hr).

- Add CompanySettingsController.DeriveBlastRate endpoint — thin GET that
  calls ShopCapabilityCalculator directly; now the single formula path
- Delete all client-side formula code (baseByCfm, multiplier tables,
  deriveBlastRate) — ~30 lines removed
- Modal live preview calls /CompanySettings/DeriveBlastRate with 250ms
  debounce instead of computing locally
- Blast setup table uses setup.derivedRate from GetBlastSetups (already
  server-computed) instead of recalculating client-side
- QuotesController.AiAnalyzeItem: when no blast setup is explicitly
  selected, fall back to the company's default blast setup so the
  configured rate is always used

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/PowderCoating.Web/Controllers/CompanySettingsController.cs

@@ -1726,6 +1726,26 @@ public class CompanySettingsController : Controller
 
     #region Blast Setups
 
+    /// <summary>
+    /// Single authoritative blast-rate calculation endpoint. Takes equipment parameters and
+    /// returns the sqft/hr rate using the same ShopCapabilityCalculator formula the AI uses.
+    /// The modal live preview calls this instead of duplicating the formula in JavaScript.
+    /// </summary>
+    [HttpGet]
+    public IActionResult DeriveBlastRate(decimal cfm, int nozzle, int setupType, int substrate, decimal? rateOverride)
+    {
+        var setup = new CompanyBlastSetup
+        {
+            CompressorCfm                = cfm,
+            BlastNozzleSize              = nozzle,
+            SetupType                    = (BlastSetupType)setupType,
+            PrimarySubstrate             = (BlastSubstrateType)substrate,
+            BlastRateSqFtPerHourOverride = rateOverride > 0 ? rateOverride : null
+        };
+        var rate = ShopCapabilityCalculator.GetBlastRateSqFtPerHour(setup);
+        return Json(new { rate });
+    }
+
     /// <summary>Returns all active blast setups for the current company with their derived rates.</summary>
     [HttpGet]
     public async Task<IActionResult> GetBlastSetups()

src/PowderCoating.Web/Controllers/QuotesController.cs

@@ -3435,13 +3435,21 @@ public class QuotesController : Controller
             // Build company AI context: profile text + recent accepted predictions as few-shot examples
             var aiContext = await BuildCompanyAiContextAsync(companyId, costs);
 
-            // Load the specific blast setup when the user picked one before analyzing
+            // Load the specific blast setup when the user picked one before analyzing.
+            // If none was explicitly chosen, fall back to the company's default blast setup so
+            // named-setup rates (e.g. a blast cabinet configured at 82 sqft/hr) are always
+            // used instead of the coarser company-level operating cost fallback.
             CompanyBlastSetup? selectedBlastSetup = null;
             if (request.BlastSetupId.HasValue)
             {
                 var setups = await _unitOfWork.BlastSetups.FindAsync(b => b.Id == request.BlastSetupId.Value && b.IsActive && b.CompanyId == companyId);
                 selectedBlastSetup = setups.FirstOrDefault();
             }
+            else
+            {
+                var defaultSetups = await _unitOfWork.BlastSetups.FindAsync(b => b.IsDefault && b.IsActive && b.CompanyId == companyId);
+                selectedBlastSetup = defaultSetups.FirstOrDefault();
+            }
 
             var result = await _aiService.AnalyzeItemAsync(request, photos, costs, avgPowderCost, aiContext, selectedBlastSetup);
             await _usageLogger.LogAsync(companyId, user?.Id ?? "", AppConstants.AiFeatures.PhotoQuote, result.Success, photos.Sum(p => p.Data.Length));

src/PowderCoating.Web/wwwroot/js/company-settings-lookups.js

@@ -1094,30 +1094,31 @@
         3: 'Powder Coat'
     };
 
-    // Nozzle multipliers matching ShopCapabilityCalculator
+    // No client-side blast-rate formula here — ShopCapabilityCalculator.cs is the single
-    const blastNozzleMultipliers = [0, 0, 0.35, 0.55, 0.75, 1.00, 1.30, 1.65, 2.00];
+    // source of truth. The table uses derivedRate from the server response; the modal
-    const blastSetupModalTypeMultipliers = { 0: 0.55, 1: 0.70, 2: 1.00, 3: 0.45 };
+    // live-preview calls /CompanySettings/DeriveBlastRate instead.
-    const blastSubstrateMultipliers = { 0: 1.00, 1: 0.80, 2: 1.40, 3: 0.90 };
 
-    function baseByCfm(cfm) {
+    let _deriveRateTimer = null;
-        if (cfm <= 0) return 0;
-        if (cfm <= 5) return 15;
-        if (cfm <= 10) return 30;
-        if (cfm <= 15) return 50;
-        if (cfm <= 25) return 80;
-        if (cfm <= 40) return 130;
-        if (cfm <= 60) return 200;
-        return 300;
-    }
 
-    function deriveBlastRate(cfm, nozzle, setupType, substrate, override) {
+    function updateBlastSetupDerivedRate() {
-        if (override && parseFloat(override) > 0) return parseFloat(override);
+        clearTimeout(_deriveRateTimer);
-        const base = baseByCfm(parseFloat(cfm) || 0);
+        _deriveRateTimer = setTimeout(function () {
-        if (base === 0) return 0;
+            const cfm       = document.getElementById('blastSetupCfm').value;
-        const nm = blastNozzleMultipliers[parseInt(nozzle)] || 1.00;
+            const nozzle    = document.getElementById('blastSetupNozzleSize').value;
-        const sm = blastSetupModalTypeMultipliers[parseInt(setupType)] || 1.00;
+            const setupType = document.getElementById('blastSetupModalType').value;
-        const bm = blastSubstrateMultipliers[parseInt(substrate)] || 1.00;
+            const substrate = document.getElementById('blastSetupSubstrate').value;
-        return Math.round(base * nm * sm * bm * 10) / 10;
+            const override  = document.getElementById('blastSetupOverride').value;
+            const el        = document.getElementById('blastSetupDerivedRate');
+            if (!el) return;
+
+            const params = new URLSearchParams({ cfm, nozzle, setupType, substrate });
+            if (override && parseFloat(override) > 0) params.set('rateOverride', override);
+
+            fetch('/CompanySettings/DeriveBlastRate?' + params)
+                .then(r => r.json())
+                .then(data => { el.textContent = data.rate > 0 ? data.rate + ' sqft/hr' : '—'; })
+                .catch(() => { el.textContent = '—'; });
+        }, 250);
     }
 
     window.loadBlastSetups = function () {
@@ -1150,7 +1151,7 @@
         window.blastSetups.forEach(function (setup) {
             const rate = setup.blastRateSqFtPerHourOverride > 0
                 ? setup.blastRateSqFtPerHourOverride + ' sqft/hr <span class="badge bg-secondary">Override</span>'
-                : deriveBlastRate(setup.compressorCfm, setup.blastNozzleSize, setup.setupType, setup.primarySubstrate, 0) + ' sqft/hr';
+                : (setup.derivedRate > 0 ? setup.derivedRate + ' sqft/hr' : '<span class="text-muted">—</span>');
 
             const defaultBadge = setup.isDefault
                 ? ' <span class="badge bg-primary ms-1">Default</span>'
@@ -1179,20 +1180,6 @@
         });
     }
 
-    function updateBlastSetupDerivedRate() {
-        const cfm = document.getElementById('blastSetupCfm').value;
-        const nozzle = document.getElementById('blastSetupNozzleSize').value;
-        const setupType = document.getElementById('blastSetupModalType').value;
-        const substrate = document.getElementById('blastSetupSubstrate').value;
-        const override = document.getElementById('blastSetupOverride').value;
-
-        const rate = deriveBlastRate(cfm, nozzle, setupType, substrate, override);
-        const el = document.getElementById('blastSetupDerivedRate');
-        if (el) {
-            el.textContent = rate > 0 ? rate + ' sqft/hr' : '—';
-        }
-    }
-
     window.showBlastSetupModal = function (setupId = null) {
         const modal = new bootstrap.Modal(document.getElementById('blastSetupModal'));
         const form = document.getElementById('blastSetupForm');

src/PowderCoating.Web/wwwroot/js/item-wizard.js

@@ -1510,8 +1510,11 @@ async function aiAnalyze() {
     document.getElementById('ai_resultsSection')?.classList.add('d-none');
     document.getElementById('ai_errorAlert')?.classList.add('d-none');
 
-    const blastSetupIdEl = document.getElementById('ai_blastSetupId');
+    const blastSetupIdEl  = document.getElementById('ai_blastSetupId');
-    const blastSetupId   = blastSetupIdEl ? (parseInt(blastSetupIdEl.value) || null) : null;
+    const _defaultSetup   = blastSetupData.find(s => s.isDefault) || blastSetupData[0];
+    const blastSetupId    = blastSetupIdEl
+        ? (parseInt(blastSetupIdEl.value) || null)
+        : (_defaultSetup ? _defaultSetup.id : null);
 
     const payload = {
         photoTempIds:        wz.ai.tempIds,
@@ -1590,8 +1593,11 @@ async function aiSendFollowup() {
     const weightLbs    = isNaN(weightLbsRaw) || weightLbsRaw <= 0 ? null : weightLbsRaw;
     wz.data.quantity = qty;  // persist before renderStep re-renders
 
-    const blastSetupIdEl2 = document.getElementById('ai_blastSetupId');
+    const blastSetupIdEl2  = document.getElementById('ai_blastSetupId');
-    const blastSetupId2   = blastSetupIdEl2 ? (parseInt(blastSetupIdEl2.value) || null) : null;
+    const _defaultSetup2   = blastSetupData.find(s => s.isDefault) || blastSetupData[0];
+    const blastSetupId2    = blastSetupIdEl2
+        ? (parseInt(blastSetupIdEl2.value) || null)
+        : (_defaultSetup2 ? _defaultSetup2.id : null);
 
     const payload = {
         photoTempIds:        wz.ai.tempIds,