/**
 * DIRECT CALCULATION WITH STDDEV INTEGRATION
 * ==========================================
 * Replace the d-calc button handler in roll_calculator.html with this code
 * 
 * This includes:
 * 1. Diameter calculation with ±2σ ranges
 * 2. Weight calculation with ±2σ ranges
 * 3. Forklift check with worst-case weight
 * 4. Load Optimizer integration with nominal values
 */

// This code should replace the existing d-calc button handler
// Find: document.getElementById('d-calc').addEventListener('click', () => { ... });
// Replace with the code below:

document.getElementById('d-calc')?.addEventListener('click', () => {
  console.log('[DirectCalc] Starting calculation...');
  
  const mode     = document.querySelector('.mode-btn.active')?.dataset.mode || 'diameter';
  const d_mm     = parseFloat(document.getElementById('d-co').value)  || 0;
  const t_mm     = parseFloat(document.getElementById('d-th').value)  || 0;
  const tol      = parseFloat(document.getElementById('d-tol').value) || 0;
  const L_m      = parseFloat(document.getElementById('d-le').value)  || 0;
  const D_mm     = parseFloat(document.getElementById('d-di').value)  || 0;
  const category = (document.getElementById('d-cat')?.value || '').toLowerCase();
  
  const resBox   = document.getElementById('d-result');
  const resLabel = document.getElementById('d-res-label');
  const resVal   = document.getElementById('d-res-val');
  const resRange = document.getElementById('d-res-range');
  
  // =====================================================
  // MODE: DIAMETER CALCULATION (with stddev)
  // =====================================================
  if (mode === 'diameter') {
    if (!d_mm || !t_mm || !L_m) {
      alert('Please enter: Core Diameter (d), Product Thickness (t), and Product Length (L).');
      return;
    }
    
    // Get stddev from data attribute (set during article selection)
    const t_stddev = parseFloat(document.getElementById('d-th')?.dataset.stddev || 0);
    
    // Calculate diameter ranges using StdDev calculator
    let diameterRanges = null;
    if (window.StdDevCalculator && t_stddev > 0) {
      diameterRanges = window.StdDevCalculator.calculateDiameterRanges(d_mm, t_mm, t_stddev, L_m);
      console.log('[DirectCalc] Diameter with stddev:', diameterRanges);
    } else {
      // Fallback: simple calculation without stddev
      const D_nom = Math.sqrt(d_mm*d_mm + (4*L_m*1000*t_mm)/Math.PI);
      diameterRanges = {
        min: D_nom, nom: D_nom, max: D_nom,
        t_min: t_mm, t_nom: t_mm, t_max: t_mm
      };
      console.log('[DirectCalc] Diameter without stddev (nominal only):', D_nom.toFixed(1));
    }
    
    // Display diameter result
    resLabel.textContent = 'Roll Diameter (D)';
    resVal.textContent = diameterRanges.nom.toFixed(1) + ' mm';
    
    if (t_stddev > 0) {
      const d_low = Math.min(diameterRanges.min, diameterRanges.max);
      const d_high = Math.max(diameterRanges.min, diameterRanges.max);
      let rangeText = `Range (±2σ): ${d_low.toFixed(1)}–${d_high.toFixed(1)} mm`;
      
      if (tol > 0) {
        const d_tol_min = diameterRanges.nom - tol;
        const d_tol_max = diameterRanges.nom + tol;
        rangeText += ` | Tolerance: ${d_tol_min.toFixed(1)}–${d_tol_max.toFixed(1)} mm`;
      }
      resRange.textContent = rangeText;
    } else {
      if (tol > 0) {
        const D_min = Math.sqrt(d_mm*d_mm + (4*L_m*1000*(t_mm-tol))/Math.PI);
        const D_max = Math.sqrt(d_mm*d_mm + (4*L_m*1000*(t_mm+tol))/Math.PI);
        resRange.textContent = `Tolerance: ${D_min.toFixed(1)}–${D_max.toFixed(1)} mm`;
      } else {
        resRange.textContent = '';
      }
    }
    
    document.getElementById('d-di').value = diameterRanges.nom.toFixed(1);
    resBox.style.display = 'block';
    
    // =====================================================
    // WEIGHT CALCULATION WITH STDDEV
    // =====================================================
    const wi = parseFloat(document.getElementById('de-wi').value) || 0;
    const aw = parseFloat(document.getElementById('d-aw').value) || 0;
    const aw_stddev = parseFloat(document.getElementById('d-aw')?.dataset.stddev || 0);
    
    let weightRanges = null;
    if (wi > 0 && aw > 0) {
      if (window.StdDevCalculator && aw_stddev > 0) {
        weightRanges = window.StdDevCalculator.calculateWeightRanges(aw, aw_stddev, L_m, wi);
        console.log('[DirectCalc] Weight with stddev:', weightRanges);
      } else {
        const w = (aw * L_m * wi / 1000);
        weightRanges = { min: w, nom: w, max: w };
        console.log('[DirectCalc] Weight without stddev:', w.toFixed(1), 'kg');
      }
      
      // Store weight in field with data attributes
      const woEl = document.getElementById('d-wo');
      woEl.value = weightRanges.nom.toFixed(1);
      woEl.dataset.weight_nom = weightRanges.nom.toFixed(1);
      woEl.dataset.weight_min = weightRanges.min.toFixed(1);
      woEl.dataset.weight_max = weightRanges.max.toFixed(1);
    }
    
    // =====================================================
    // FORKLIFT CHECK WITH WORST-CASE WEIGHT
    // =====================================================
    if (window.ForkliftChecker && weightRanges) {
      const worstCaseWeight = Math.max(weightRanges.nom, weightRanges.max);
      const allowed = window.ForkliftChecker.evaluate(worstCaseWeight, d_mm, category);
      
      if (!allowed) {
        resBox.style.display = 'none'; // Hide result if blocked
      }
      
      console.log('[DirectCalc] Forklift check:', {
        nominal: weightRanges.nom.toFixed(1),
        worst_case: worstCaseWeight.toFixed(1),
        allowed: allowed
      });
    }
    
    // =====================================================
    // LOAD OPTIMIZER INTEGRATION (nominal values)
    // =====================================================
    if (window.loadOptimizerUI && diameterRanges && weightRanges) {
      window.loadOptimizerUI.optimizer.setRollData({
        rollDiameter: diameterRanges.nom,
        coreDiameter: d_mm,
        rollWidth: wi,
        rollWeight: weightRanges.nom,  // Use nominal for capacity planning
        m2PerRoll: L_m * wi,
        productLength: L_m
      });
      console.log('[DirectCalc] Load Optimizer updated with nominal values');
    }
  }
  
  // =====================================================
  // MODE: PRODUCT LENGTH CALCULATION
  // =====================================================
  else if (mode === 'length') {
    if (!d_mm || !t_mm || !D_mm) {
      alert('Please enter: Core Diameter (d), Product Thickness (t), and Roll Diameter (D).');
      return;
    }
    
    const L = (Math.PI / (4 * t_mm)) * (D_mm*D_mm - d_mm*d_mm) / 1000;
    resLabel.textContent = 'Product Length (L)';
    resVal.textContent = L.toFixed(2) + ' m';
    
    if (tol > 0) {
      const L_min = (Math.PI / (4*(t_mm+tol))) * (D_mm*D_mm - d_mm*d_mm) / 1000;
      const L_max = (Math.PI / (4*(t_mm-tol))) * (D_mm*D_mm - d_mm*d_mm) / 1000;
      resRange.textContent = `Range: ${L_min.toFixed(2)}–${L_max.toFixed(2)} m`;
    } else {
      resRange.textContent = '';
    }
    
    document.getElementById('d-le').value = L.toFixed(2);
    resBox.style.display = 'block';
  }
  
  // =====================================================
  // MODE: TARGET DIAMETER
  // =====================================================
  else if (mode === 'target') {
    if (!d_mm || !t_mm) {
      alert('Please enter: Core Diameter (d) and Product Thickness (t).');
      return;
    }
    
    const D_target = D_mm || 800;
    const L = (Math.PI / (4 * t_mm)) * (D_target*D_target - d_mm*d_mm) / 1000;
    resLabel.textContent = `Product Length for Ø ${D_target} mm`;
    resVal.textContent = L.toFixed(2) + ' m';
    resRange.textContent = '';
    
    document.getElementById('d-le').value = L.toFixed(2);
    resBox.style.display = 'block';
  }
  
  // =====================================================
  // MODE: PRODUCT THICKNESS
  // =====================================================
  else if (mode === 'thickness') {
    if (!d_mm || !D_mm || !L_m) {
      alert('Please enter: Core Diameter (d), Roll Diameter (D), and Product Length (L).');
      return;
    }
    
    const t = (Math.PI / (4 * L_m * 1000)) * (D_mm*D_mm - d_mm*d_mm);
    resLabel.textContent = 'Product Thickness (t)';
    resVal.textContent = t.toFixed(3) + ' mm';
    resRange.textContent = '';
    
    document.getElementById('d-th').value = t.toFixed(3);
    resBox.style.display = 'block';
  }
  
  console.log('[DirectCalc] Calculation complete');
});