/**
 * Moteur de calcul de prix — configurateur armoires sur mesure.
 * Règles : panneaux entiers (chute intégrée), blocs, kit, options.
 * Specs APEX 4.0 importées de shared/manufacturing.js
 */

import {
  PANEL,
  DRAWERS,
  NICHE,
  HANDLE,
  PLINTH,
  getAxiloPlinthPanelHeightMm,
  hasSidePlinthReturn,
  getAxiloPlinthReturnLengthMm,
  getHingeCountForDoor,
  resolveHorizontalSpan,
  validateHorizontalSpans,
  usesBlockConstruction,
  MAX_PANEL_DIMENSION_MM
} from '../../shared/manufacturing.js';

function numberOr(value, fallback) {
  const n = typeof value === 'number' ? value : Number(value);
  return Number.isFinite(n) ? n : fallback;
}

function resolvedHorizontalSpansForConfig(config) {
  if (!Array.isArray(config?.horizontalSpans) || config.horizontalSpans.length === 0) return [];
  const invalidIds = new Set(
    validateHorizontalSpans(config)
      .map((issue) => issue?.spanId)
      .filter((id) => id != null)
      .map(String)
  );
  return config.horizontalSpans
    .filter((span) => span?.id != null && !invalidIds.has(String(span.id)))
    .map((span) => resolveHorizontalSpan(span, config))
    .filter(Boolean);
}

function spanCoversBlock(resolvedSpans, moduleIndex, bottomMm, topMm) {
  const eps = 0.5;
  return resolvedSpans.some((span) =>
    span.moduleIndexes.includes(moduleIndex) &&
    bottomMm >= span.bottomMm - eps &&
    topMm <= span.topMm + eps
  );
}

/**
 * Calcule la surface utile des éléments visibles (portes, fileurs, bandeau, plinthe, côtés doublage).
 * Épaisseur panneaux 19 mm (référence APEX 4.0).
 * @param {Object} config - configuration (installation, width, height, depth, plinthHeightMm, blocks, doorType, slidingPanels)
 * @param {number} panelThicknessMm - épaisseur panneaux (19)
 */
function calculateVisibleSurface(config, panelThicknessMm = PANEL.structure) {
  const { installationType, widthMm, heightMm, depthMm, plinthHeightMm, blocks = [], doorType, slidingPanelsCount } = config;
  const isNiche = installationType === 'niche';
  let surface = 0;

  // Portes (surface face visible)
  if (doorType === 'sliding' && slidingPanelsCount) {
    const panelWidth = widthMm / slidingPanelsCount;
    surface += slidingPanelsCount * (panelWidth * (heightMm - plinthHeightMm)) * 2; // deux faces par vantail
  } else if (Array.isArray(config.modules) && config.modules.length > 0) {
    // 1 porte par block AVEC porte (mod.blockDoors); block sans porte = niche ouverte, pas de façade.
    const bodyMm = heightMm - plinthHeightMm;
    const resolvedSpans = resolvedHorizontalSpansForConfig(config);
    for (let moduleIndex = 0; moduleIndex < config.modules.length; moduleIndex++) {
      const m = config.modules[moduleIndex];
      const colW = Number(m?.widthMm) || widthMm / config.modules.length;
      const arr = Array.isArray(m?.blockHeightsMm)
        ? m.blockHeightsMm.map(Number).filter((v) => Number.isFinite(v) && v > 0)
        : null;
      let heights;
      if (arr && arr.length > 0) {
        heights = arr;
      } else {
        const stacked = typeof m?.stacked === 'boolean' ? m.stacked : config.stackEnabled === true;
        heights = stacked && bodyMm >= 600
          ? [Number(m?.stackBottomHeightMm ?? config.stackBottomHeightMm) || 1000]
            .flatMap((b) => [b, bodyMm - b])
          : [bodyMm];
      }
      const doors = Array.isArray(m?.blockDoors) ? m.blockDoors : null;
      let blockBottomMm = 0;
      heights.forEach((h, k) => {
        const blockTopMm = blockBottomMm + h;
        const covered = spanCoversBlock(resolvedSpans, moduleIndex, blockBottomMm, blockTopMm);
        blockBottomMm = blockTopMm;
        const hasDoor = doors && typeof doors[k] === 'boolean' ? doors[k] : true;
        if (hasDoor && !covered) surface += colW * h * 2; // deux faces
      });
    }
    const fullHeightDeduction =
      config.hardware?.handleType === 'full_height' ? HANDLE.fullHeightWidthDeductionMm : 0;
    for (const span of resolvedSpans) {
      const doorMode = span.span?.doorMode || 'none';
      if (doorMode === 'none') continue;
      const doorHeightMm = Math.max(120, span.topMm - span.bottomMm - 4);
      if (doorMode === 'single') {
        const doorWidthMm = Math.max(100, span.widthMm - 4 - fullHeightDeduction);
        surface += doorWidthMm * doorHeightMm * 2;
      } else if (doorMode === 'perColumn') {
        for (let leafIndex = 0; leafIndex < 2; leafIndex++) {
          const doorWidthMm = Math.max(
            100,
            Math.floor(span.widthMm / 2) - 4 - fullHeightDeduction
          );
          surface += doorWidthMm * doorHeightMm * 2;
        }
      }
    }
  } else {
    const doorsCount = blocks.length <= 1 ? Math.min(2, Math.ceil((blocks[0]?.widthMm || widthMm) / 600)) : blocks.length * 2;
    const doorWidth = widthMm / Math.max(1, doorsCount);
    surface += doorsCount * (doorWidth * (heightMm - plinthHeightMm)) * 2;
  }

  // Plinthe (face avant + retours latéraux s'il n'y a pas d'habillage)
  const plinthH = getAxiloPlinthPanelHeightMm(plinthHeightMm);
  surface += widthMm * plinthH;
  if (hasSidePlinthReturn(config, 'left')) {
    surface += getAxiloPlinthReturnLengthMm(depthMm) * plinthH;
  }
  if (hasSidePlinthReturn(config, 'right')) {
    surface += getAxiloPlinthReturnLengthMm(depthMm) * plinthH;
  }

  // Bandeau et fileurs si niche
  if (isNiche) {
    surface += widthMm * plinthHeightMm; // bandeau haut
    surface += 2 * plinthHeightMm * (heightMm - plinthHeightMm); // fileurs gauche/droite
  }

  // Côtés de doublage (coulissant)
  if (doorType === 'sliding') {
    surface += 2 * (depthMm * (heightMm - plinthHeightMm));
  }

  return surface / 1_000_000; // m²
}

/**
 * Nombre de panneaux entiers nécessaires (arrondi supérieur).
 * Coût = nombre_panneaux × prix_panneau.
 */
function panelCost(surfaceM2, panelWidthMm, panelHeightMm, pricePerPanelChf) {
  const panelSurfaceM2 = (panelWidthMm * panelHeightMm) / 1_000_000;
  const count = Math.ceil(surfaceM2 / panelSurfaceM2);
  return { panels: Math.max(0, count), costChf: count * pricePerPanelChf };
}

/**
 * Find the optimal dimension variant that minimizes cost (fewest panels needed).
 * @param {number} surfaceM2 - Required surface in square meters
 * @param {Array} dimensions - Array of dimension variants [{width_mm, height_mm, thickness_mm, id}]
 * @param {number} pricePerPanel - Price per panel in CHF
 * @returns {Object} - Optimal dimension with cost details and alternatives
 */
function findOptimalDimension(surfaceM2, dimensions, pricePerPanel) {
  if (!dimensions || dimensions.length === 0) {
    return null;
  }
  
  const price = pricePerPanel || 0;
  const results = [];
  
  for (const dim of dimensions) {
    if (!dim.width_mm || !dim.height_mm) continue;
    
    const panelSurfaceM2 = (dim.width_mm * dim.height_mm) / 1_000_000;
    const panelsNeeded = Math.ceil(surfaceM2 / panelSurfaceM2);
    const totalCost = panelsNeeded * price;
    const totalSurface = panelsNeeded * panelSurfaceM2;
    const wasteM2 = totalSurface - surfaceM2;
    const wastePercent = (wasteM2 / totalSurface) * 100;
    
    results.push({
      dimension: {
        id: dim.id,
        width_mm: dim.width_mm,
        height_mm: dim.height_mm,
        thickness_mm: dim.thickness_mm
      },
      panelsNeeded,
      costChf: totalCost,
      panelSurfaceM2,
      wasteM2: Math.round(wasteM2 * 1000) / 1000,
      wastePercent: Math.round(wastePercent * 10) / 10
    });
  }
  
  // Sort by cost (lowest first), then by waste (lowest first)
  results.sort((a, b) => {
    if (a.costChf !== b.costChf) return a.costChf - b.costChf;
    return a.wasteM2 - b.wasteM2;
  });
  
  if (results.length === 0) return null;
  
  const optimal = results[0];
  const alternatives = results.slice(1);
  
  return {
    selectedDimension: optimal.dimension,
    panelsNeeded: optimal.panelsNeeded,
    costChf: optimal.costChf,
    wasteM2: optimal.wasteM2,
    wastePercent: optimal.wastePercent,
    alternatives: alternatives.map(alt => ({
      dimension: alt.dimension,
      panelsNeeded: alt.panelsNeeded,
      costChf: alt.costChf,
      wasteM2: alt.wasteM2,
      wastePercent: alt.wastePercent
    }))
  };
}

/**
 * Calculate module costs (V2 mode)
 * @param {Array} modules - Array of module configurations
 * @param {Array} moduleCatalog - Available modules from database
 * @returns {Object} - Module costs breakdown
 */
function calculateModuleCosts(modules, moduleCatalog) {
  let totalChf = 0;
  const breakdown = [];
  
  for (const module of modules) {
    const catalogModule = moduleCatalog.find(m => m.id === module.moduleTypeId || m.code === module.moduleCode);
    const basePrice = catalogModule?.base_price_chf || 450;
    
    // Adjust price based on customizations
    let adjustedPrice = basePrice;
    
    // Extra shelves cost (beyond default)
    const defaultShelves = catalogModule?.shelves_count || 0;
    const extraShelves = Math.max(0, (module.shelves || 0) - defaultShelves);
    adjustedPrice += extraShelves * 25; // 25 CHF per extra shelf
    
    // Extra drawers cost (beyond default)  
    const defaultDrawers = catalogModule?.drawers_count || 0;
    const extraDrawers = Math.max(0, (module.drawers || 0) - defaultDrawers);
    adjustedPrice += extraDrawers * 45; // 45 CHF per extra drawer
    
    // Width adjustment (if different from default)
    const defaultWidth = catalogModule?.width_mm || 600;
    const widthDiff = (module.widthMm || defaultWidth) - defaultWidth;
    if (widthDiff > 0) {
      adjustedPrice += widthDiff * 0.15; // 0.15 CHF per extra mm
    }
    
    breakdown.push({
      moduleCode: module.moduleCode || catalogModule?.code,
      moduleName: catalogModule?.name || 'Module',
      basePrice,
      adjustedPrice: Math.round(adjustedPrice * 100) / 100,
      adjustments: {
        extraShelves,
        extraDrawers,
        widthDiff
      }
    });
    
    totalChf += adjustedPrice;
  }
  
  return {
    totalChf: Math.round(totalChf * 100) / 100,
    breakdown
  };
}

/**
 * Calculate hardware costs (V2)
 * @param {Object} hardware - Hardware selection {handleVariantId, hingeVariantId, drawerSystemId}
 * @param {Object} hardwareData - Hardware data from DB {handles, hinges, blum}
 * @param {Object} config - Config with door and drawer counts
 * @returns {Object} - Hardware costs breakdown
 */
/**
 * Hauteurs (mm) des portes battantes: 1 porte par block AVEC porte (mod.blockDoors),
 * par colonne. Colonne empilée sans flags portes → 1 porte par block.
 */
function hingedDoorHeightsMm(config) {
  const bodyMm = (Number(config.heightMm) || 2400) - (Number(config.plinthHeightMm) || 100);
  const mods = Array.isArray(config.modules) && config.modules.length > 0 ? config.modules : null;
  const cols = mods ?? Array.from({ length: config.blocks?.length || 2 }, () => null);
  const resolvedSpans = mods ? resolvedHorizontalSpansForConfig(config) : [];
  const out = [];
  for (let moduleIndex = 0; moduleIndex < cols.length; moduleIndex++) {
    const m = cols[moduleIndex];
    const arr = Array.isArray(m?.blockHeightsMm)
      ? m.blockHeightsMm.map(Number).filter((v) => Number.isFinite(v) && v > 0)
      : null;
    let heights;
    if (arr && arr.length > 0) {
      heights = arr;
    } else {
      const stacked = typeof m?.stacked === 'boolean' ? m.stacked : config.stackEnabled === true;
      if (stacked && bodyMm >= 600) {
        const bottom = Number(m?.stackBottomHeightMm ?? config.stackBottomHeightMm) || 1000;
        heights = [bottom, bodyMm - bottom];
      } else {
        heights = [bodyMm];
      }
    }
    const doors = Array.isArray(m?.blockDoors) ? m.blockDoors : null;
    let blockBottomMm = 0;
    heights.forEach((h, k) => {
      const blockTopMm = blockBottomMm + h;
      const covered = spanCoversBlock(resolvedSpans, moduleIndex, blockBottomMm, blockTopMm);
      blockBottomMm = blockTopMm;
      const hasDoor = doors && typeof doors[k] === 'boolean' ? doors[k] : true;
      if (hasDoor && !covered) out.push(Math.max(80, h - 4));
    });
  }
  for (const span of resolvedSpans) {
    const doorMode = span.span?.doorMode || 'none';
    const count =
      doorMode === 'single' ? 1 :
        doorMode === 'perColumn' ? 2 : 0;
    const heightMm = Math.max(120, span.topMm - span.bottomMm - 4);
    for (let index = 0; index < count; index++) out.push(heightMm);
  }
  return out;
}

function calculateHardwareCosts(hardware, hardwareData, config) {
  const { handles = [], hinges = [], blum = [] } = hardwareData;
  const breakdown = [];
  let totalChf = 0;

  const hingedDoorHeights = config.doorType === 'sliding' ? [] : hingedDoorHeightsMm(config);

  // Handle costs - one per door (blocks sans porte exclus)
  if (hardware.handleVariantId) {
    const handle = handles.find(h => h.id === hardware.handleVariantId);
    if (handle) {
      const doorCount = config.doorType === 'sliding'
        ? (config.slidingPanelsCount || 2)
        : hingedDoorHeights.length;
      if (doorCount > 0) {
        const cost = handle.price_chf * doorCount;
        totalChf += cost;
        breakdown.push({
          type: 'handle',
          name: handle.name,
          unitPrice: handle.price_chf,
          quantity: doorCount,
          totalChf: cost
        });
      }
    }
  }

  // Hinge costs - dynamic quantity from APEX 4.0 matrix, par porte (hauteur du block)
  if (hardware.hingeVariantId && config.doorType !== 'sliding') {
    const hinge = hinges.find(h => h.id === hardware.hingeVariantId);
    if (hinge) {
      const quantity = hingedDoorHeights.reduce(
        (sum, doorHeightMm) => sum + getHingeCountForDoor({ heightMm: doorHeightMm }),
        0
      );
      if (quantity > 0) {
        const cost = hinge.price_chf * quantity;
        totalChf += cost;
        breakdown.push({
          type: 'hinge',
          name: hinge.name,
          unitPrice: hinge.price_chf,
          quantity,
          totalChf: cost
        });
      }
    }
  }
  
  // Drawer system costs - one per drawer
  if (hardware.drawerSystemId) {
    const system = blum.find(h => h.id === hardware.drawerSystemId && h.type === 'drawer_system');
    if (system) {
      const modules = config.modules || [];
      const drawerCount = modules.reduce((sum, m) => sum + (m.drawers || 0), 0);
      if (drawerCount > 0) {
        const cost = system.price_chf * drawerCount;
        totalChf += cost;
        breakdown.push({
          type: 'drawer_system',
          name: system.name,
          unitPrice: system.price_chf,
          quantity: drawerCount,
          totalChf: cost
        });
      }
    }
  }
  
  return {
    totalChf: Math.round(totalChf * 100) / 100,
    breakdown
  };
}

/**
 * Valide la configuration et calcule le prix total.
 * @param {Object} config - configuration client
 * @param {Object} data - données DB (settings, blockTypes, finishes, serviceOptions, modules, hardware)
 */
export function calculatePrice(config, data) {
  const errors = [];
  const horizontalSpanIssues =
    Array.isArray(config?.horizontalSpans) && config.horizontalSpans.length
      ? validateHorizontalSpans(config)
      : [];
  horizontalSpanIssues.forEach((issue) => errors.push({
    field: issue.field,
    message: issue.message
  }));
  const invalidHorizontalSpanIds = new Set(
    horizontalSpanIssues
      .map((issue) => issue.spanId)
      .filter((id) => id != null)
      .map(String)
  );
  const resolvedHorizontalSpans = (Array.isArray(config?.horizontalSpans) ? config.horizontalSpans : [])
    .filter((span) => span?.id != null && !invalidHorizontalSpanIds.has(String(span.id)))
    .map((span) => resolveHorizontalSpan(span, config))
    .filter(Boolean);
  const settingsArr = data.settings || [];
  const settings = {};
  for (const r of settingsArr) {
    let v = r.value;
    if (typeof v === 'string' && /^-?\d+(\.\d+)?$/.test(v)) v = Number(v);
    settings[r.key] = v;
  }
  const kitFeeChf = numberOr(settings.kit_preparation_fee_chf, 350);
  const plinthMin = numberOr(settings.plinth_height_min_mm, 60);
  const plinthMax = numberOr(settings.plinth_height_max_mm, 200);
  const slidingMinWidth = numberOr(settings.sliding_doors_min_width_mm, 1200);
  const allowSlidingDoors = String(settings.allow_sliding_doors ?? '0') === '1';
  const standardHandleAxisMm = numberOr(settings.standard_handle_axis_mm, 1000);
  const standardHandleToleranceMm = numberOr(settings.standard_handle_tolerance_mm, 200);
  const sanitaryGapMm = numberOr(settings.sanitary_gap_mm, NICHE.sanitaryGapAround);

  const { 
    installationType, widthMm, heightMm, depthMm, plinthHeightMm, 
    blocks = [], modules = [], hardware = {},
    doorType, slidingPanelsCount, finishId, serviceOptionIds = [],
    columnMode: columnModeRaw
  } = config;
  // Règle: dos → caisson block ; sinon côté ou rayonnage → block ; sinon séparations.
  // Legacy: `mod.hasBack` absent → `config.hasBack` global; les deux absents → columnMode envoyé.
  const legacyBackDefault = typeof config.hasBack === 'boolean'
    ? config.hasBack
    : columnModeRaw === 'block';
  // Empilage vertical PAR COLONNE — modèle N blocks: mod.blockHeightsMm / mod.blockBacks
  // (legacy 2 blocks: mod.stacked + mod.stackBottomHeightMm; défauts config.stackEnabled / config.stackBottomHeightMm).
  const STACK_MIN_MM = 300;
  const STACK_MAX_MM = MAX_PANEL_DIMENSION_MM; // panneau max → au-delà, empilage obligatoire
  const bodyHeightForStackMm = (Number(config.heightMm) || 0) - (Number(config.plinthHeightMm) || 100);
  const minBlocksRequired = Math.max(1, Math.ceil(bodyHeightForStackMm / STACK_MAX_MM));
  const maxBlocksAllowed = Math.max(1, Math.floor(bodyHeightForStackMm / STACK_MIN_MM));

  /** Hauteurs de blocks d'une colonne (bas → haut) telles qu'envoyées (sans normalisation silencieuse). */
  const columnBlockHeights = (modules || []).map((m) => {
    const arr = Array.isArray(m?.blockHeightsMm)
      ? m.blockHeightsMm.map(Number).filter((v) => Number.isFinite(v) && v > 0)
      : null;
    if (arr && arr.length > 0) return arr;
    const stacked = typeof m?.stacked === 'boolean' ? m.stacked : config.stackEnabled === true;
    if (stacked && bodyHeightForStackMm >= STACK_MIN_MM * 2) {
      const bottom = Number(m?.stackBottomHeightMm ?? config.stackBottomHeightMm) || 1000;
      return [bottom, bodyHeightForStackMm - bottom];
    }
    return [bodyHeightForStackMm];
  });
  const columnBlockCounts = columnBlockHeights.map((hs) => hs.length);
  const anyStacked = columnBlockCounts.some((n) => n >= 2) ||
    ((modules || []).length === 0 && config.stackEnabled === true);

  if (anyStacked && bodyHeightForStackMm < STACK_MIN_MM * 2) {
    errors.push({
      field: 'stackEnabled',
      message: `Empilage vertical impossible: hauteur de caisse insuffisante (min. ${STACK_MIN_MM * 2} mm hors plinthe).`
    });
  } else {
    columnBlockHeights.forEach((hs, i) => {
      if (hs.length < minBlocksRequired) {
        errors.push({
          field: 'blockHeightsMm',
          message: `Colonne ${i + 1}: hauteur de caisse ${bodyHeightForStackMm} mm > panneau max ${STACK_MAX_MM} mm — au moins ${minBlocksRequired} blocks empilés obligatoires.`
        });
        return;
      }
      if (hs.length > maxBlocksAllowed) {
        errors.push({
          field: 'blockHeightsMm',
          message: `Colonne ${i + 1}: trop de blocks (max. ${maxBlocksAllowed} pour ${bodyHeightForStackMm} mm, min. ${STACK_MIN_MM} mm par block).`
        });
        return;
      }
      if (hs.length >= 2) {
        const sum = hs.reduce((a, b) => a + b, 0);
        if (hs.some((h) => h < STACK_MIN_MM || h > STACK_MAX_MM)) {
          errors.push({
            field: 'blockHeightsMm',
            message: `Colonne ${i + 1}: hauteur de block invalide (entre ${STACK_MIN_MM} et ${STACK_MAX_MM} mm par block).`
          });
        } else if (Math.abs(sum - bodyHeightForStackMm) > 2) {
          errors.push({
            field: 'blockHeightsMm',
            message: `Colonne ${i + 1}: la somme des blocks (${sum} mm) doit correspondre à la hauteur de caisse (${bodyHeightForStackMm} mm).`
          });
        }
      }
    });
  }
  const stackEnabled = anyStacked && bodyHeightForStackMm >= STACK_MIN_MM * 2;

  const columnBackFlags = (modules || []).map((m) =>
    typeof m?.hasBack === 'boolean' ? m.hasBack : legacyBackDefault
  );
  /** Dos par block d'une colonne (bas → haut). */
  const columnBlockBacks = (modules || []).map((m, i) => {
    const n = columnBlockCounts[i];
    const arr = Array.isArray(m?.blockBacks) ? m.blockBacks : null;
    return Array.from({ length: n }, (_, k) => {
      if (arr && typeof arr[k] === 'boolean') return arr[k];
      if (k === n - 1 && n >= 2 && typeof m?.hasBackTop === 'boolean') return m.hasBackTop;
      return columnBackFlags[i];
    });
  });
  // Zone du dessus (dernier block, ou zone unique).
  const columnBackTopFlags = columnBlockBacks.map((backs, i) =>
    backs.length > 0 ? backs[backs.length - 1] : columnBackFlags[i]
  );
  let blockJointCount = 0;
  for (let i = 0; i + 1 < columnBlockBacks.length; i++) {
    const leftMod = (modules || [])[i];
    const rightMod = (modules || [])[i + 1];
    const leftBlock = usesBlockConstruction(leftMod, (columnBlockBacks[i] || []).some(Boolean));
    const rightBlock = usesBlockConstruction(rightMod, (columnBlockBacks[i + 1] || []).some(Boolean));
    if (!leftBlock || !rightBlock) continue;
    const n = Math.min(columnBlockBacks[i].length, columnBlockBacks[i + 1].length);
    blockJointCount += n;
  }
  const allColumnsBack =
    columnBlockBacks.length > 0 &&
    columnBlockBacks.every((backs) => backs.every(Boolean));
  const anyColumnBack =
    columnBlockBacks.some((backs) => backs.some(Boolean)) ||
    (columnBlockBacks.length === 0 && legacyBackDefault);
  const columnMode = allColumnsBack ? 'block' : (anyColumnBack ? 'mixte' : 'separations');

  // Habillages obligatoires (installation libre, configs récentes avec flags dos explicites):
  // - colonne d'extrémité empilée → habillage de ce côté seulement
  // - une zone du dessus (niveau haut, ou zone unique) sans dos → dessus de doublage obligatoire
  const hasExplicitBackFlags =
    typeof config.hasBack === 'boolean' || (modules || []).some((m) => typeof m?.hasBack === 'boolean');
  if (installationType === 'free' && (modules || []).length > 0 && hasExplicitBackFlags) {
    const extOn = config.exteriorFinishesEnabled !== false;
    const sideDefaults = config.sideFinishesEnabled !== false;
    const sideL = config.sideFinishLeftEnabled ?? sideDefaults;
    const sideR = config.sideFinishRightEnabled ?? sideDefaults;
    const topOn = config.topFinishEnabled !== false;
    const leftOuterStacked = columnBlockCounts[0] >= 2;
    const rightOuterStacked = columnBlockCounts[columnBlockCounts.length - 1] >= 2;
    if (leftOuterStacked && (!extOn || !sideL)) {
      errors.push({
        field: 'sideFinishLeftEnabled',
        message: 'Colonne gauche empilée (plusieurs blocks en hauteur) : habillage gauche obligatoire.'
      });
    }
    if (rightOuterStacked && (!extOn || !sideR)) {
      errors.push({
        field: 'sideFinishRightEnabled',
        message: 'Colonne droite empilée (plusieurs blocks en hauteur) : habillage droit obligatoire.'
      });
    }
    if (columnBackTopFlags.some((b) => !b) && (!extOn || !topOn)) {
      errors.push({
        field: 'topFinishEnabled',
        message: 'Une zone du dessus (niveau haut) sans dos : dessus de doublage obligatoire.'
      });
    }
  }

  // Determine if using modules (V2) or blocks (legacy)
  const useModules = modules && modules.length > 0;

  // Plinthe (bornes paramétrables, défaut 60–200 mm)
  if (plinthHeightMm < plinthMin || plinthHeightMm > plinthMax) {
    errors.push({ field: 'plinthHeightMm', message: `La hauteur de plinthe doit être entre ${plinthMin} et ${plinthMax} mm.` });
  } else if (!PLINTH.targetHeightsMm.includes(Number(plinthHeightMm))) {
    errors.push({
      field: 'plinthHeightMm',
      message: `Hauteur AXILO 78 invalide. Valeurs admises : ${PLINTH.targetHeightsMm.join(', ')} mm.`
    });
  }

  // Portes coulissantes : largeur totale >= 1200 mm
  if (doorType === 'sliding' && widthMm < slidingMinWidth) {
    errors.push({ field: 'doorType', message: `Les portes coulissantes ne sont possibles qu'à partir de ${slidingMinWidth} mm de largeur.` });
  }
  if (doorType === 'sliding' && !allowSlidingDoors) {
    errors.push({ field: 'doorType', message: 'Les portes coulissantes sont désactivées pour le moment.' });
  }

  if (doorType === 'sliding' && (slidingPanelsCount < 2 || slidingPanelsCount > 3)) {
    errors.push({ field: 'slidingPanelsCount', message: 'Choisissez 2 ou 3 vantaux coulissants.' });
  }

  if (installationType === 'niche') {
    const nm = config.nicheMeasurements || {};
    const minW = Math.min(nm.widthTopMm || widthMm, nm.widthMidMm || widthMm, nm.widthBottomMm || widthMm);
    const minD = Math.min(nm.depthTopMm || depthMm, nm.depthMidMm || depthMm, nm.depthBottomMm || depthMm);
    const minH = Math.min(nm.heightLeftMm || heightMm, nm.heightRightMm || heightMm);
    const expectedW = Math.max(400, minW - sanitaryGapMm * 2);
    const expectedD = Math.max(400, minD - sanitaryGapMm * 2);
    const expectedH = Math.max(1800, minH - sanitaryGapMm * 2);
    if (Math.abs(widthMm - expectedW) > 2 || Math.abs(depthMm - expectedD) > 2 || Math.abs(heightMm - expectedH) > 2) {
      errors.push({ field: 'nicheMeasurements', message: 'Les dimensions retenues ne correspondent pas aux plus petites mesures niche avec vide sanitaire de 3 cm.' });
    }
  }

  const handleAxis = Number(config.hardware?.handleBoreHeightMm || standardHandleAxisMm);
  const minStandard = standardHandleAxisMm - standardHandleToleranceMm;
  const maxStandard = standardHandleAxisMm + standardHandleToleranceMm;
  const isHandleAxisNonStandard = handleAxis < minStandard || handleAxis > maxStandard;

  // Calculate block/module costs
  let blocksChf = 0;
  let modulesBreakdown = null;
  
  if (useModules) {
    // V2: Use module-based pricing
    const moduleCatalog = data.modules || [];
    const moduleCosts = calculateModuleCosts(modules, moduleCatalog);
    blocksChf = moduleCosts.totalChf;
    modulesBreakdown = moduleCosts.breakdown;
    
    // Validate module widths
    const totalModuleWidth = modules.reduce((sum, m) => sum + (m.widthMm || 0), 0);
    if (Math.abs(totalModuleWidth - widthMm) > 10) {
      errors.push({ field: 'modules', message: `La somme des largeurs des modules (${totalModuleWidth}mm) doit correspondre à la largeur totale (${widthMm}mm).` });
    }
    const hasDrawerColumnTooWide = modules.some((m) => ((m.drawers || 0) > 0 || m.type === 'tiroirs') && (m.widthMm || 0) > DRAWERS.maxColumnWidth);
    if (hasDrawerColumnTooWide) {
      errors.push({ field: 'modules', message: `Une colonne tiroirs dépasse ${DRAWERS.maxColumnWidth} mm (non autorisé).` });
    }
    if (modules.some((m) => m.hasRod) && heightMm < 1200) {
      errors.push({ field: 'modules', message: 'Rayon avec tringle: hauteur minimale 1200 mm.' });
    }
  } else {
    // Legacy: Use block-based pricing
    const totalWidth = blocks.reduce((sum, b) => sum + (b.widthMm || 0), 0);
    if (Math.abs(totalWidth - widthMm) > 5 && blocks.length > 0) {
      errors.push({ field: 'blocks', message: 'La somme des largeurs des blocs doit correspondre à la largeur totale.' });
    }

    const blockTypes = data.blockTypes || [];
    for (const block of blocks) {
      const bt = blockTypes.find((b) => b.id === block.blockTypeId || b.code === block.blockTypeCode);
      if (bt) blocksChf += Number(bt.base_price_chf) || 550;
      else blocksChf += 550;
    }
  }

  // Calculate hardware costs (V2)
  let hardwareChf = 0;
  let hardwareBreakdown = null;
  
  if (hardware && (hardware.handleVariantId || hardware.hingeVariantId || hardware.drawerSystemId)) {
    const hardwareData = {
      handles: data.handles || [],
      hinges: data.hinges || [],
      blum: data.blumHardware || []
    };
    const hardwareCosts = calculateHardwareCosts(hardware, hardwareData, config);
    hardwareChf = hardwareCosts.totalChf;
    hardwareBreakdown = hardwareCosts.breakdown;
  }

  let panelsChf = 0;
  let panelOptimization = null;
  
  const surfaceM2 = calculateVisibleSurface({
    ...config,
    widthMm: widthMm || blocks.reduce((sum, b) => sum + (b.widthMm || 0), 0),
    plinthHeightMm: plinthHeightMm || 100,
    blocks: useModules ? modules.map(m => ({ widthMm: m.widthMm })) : blocks,
    doorType: doorType || 'hinged',
    slidingPanelsCount: slidingPanelsCount || 2
  });
  
  // Find finish/material by ID or code
  const finish = (data.finishes || []).find((f) => f.id === finishId || f.code === config.finishCode);
  
  if (finish) {
    const priceChf = finish.price_chf;
    
    // Check if we have multiple dimension variants for optimization
    if (finish.dimensions && finish.dimensions.length > 0 && priceChf != null) {
      // Auto-optimize: find the best dimension that minimizes cost
      panelOptimization = findOptimalDimension(surfaceM2, finish.dimensions, Number(priceChf));
      
      if (panelOptimization) {
        panelsChf = panelOptimization.costChf;
      }
    } else if (finish.width_mm && finish.height_mm && priceChf != null) {
      // Legacy: single dimension from finish
      const result = panelCost(surfaceM2, finish.width_mm, finish.height_mm, Number(priceChf));
      panelsChf = result.costChf;
      
      // Create optimization info for legacy finishes
      const panelSurfaceM2 = (finish.width_mm * finish.height_mm) / 1_000_000;
      const wasteM2 = (result.panels * panelSurfaceM2) - surfaceM2;
      panelOptimization = {
        selectedDimension: {
          width_mm: finish.width_mm,
          height_mm: finish.height_mm,
          thickness_mm: null
        },
        panelsNeeded: result.panels,
        costChf: result.costChf,
        wasteM2: Math.round(wasteM2 * 1000) / 1000,
        wastePercent: Math.round((wasteM2 / (result.panels * panelSurfaceM2)) * 1000) / 10,
        alternatives: []
      };
    }
  }

  // Renforts Forteresse — one pair (haut+bas) per panneau vertical de structure
  // Séparations: 2 côtés + (n−1) séparateurs = n+1 panneaux verticaux
  // Chaque jonction caisson↔caisson (dos ou rayonnage adjacents) ajoute 1 montant (double montant)
  const columnCount = useModules
    ? Math.max(1, modules.length)
    : Math.max(1, blocks.length || 1);
  const legacyBlockJoints = !useModules && columnModeRaw === 'block'
    ? Math.max(0, columnCount - 1)
    : blockJointCount;
  const verticalStructurePanelCount = 2 + Math.max(0, columnCount - 1) + legacyBlockJoints;
  const reinforcementCount = verticalStructurePanelCount * 2;

  // Surcoût panneaux 19 mm (structure): 1 montant supplémentaire par jonction caisson↔caisson
  const bodyHeightMm = (heightMm || 0) - (plinthHeightMm || 100);
  const extraBlockVerticalPanels = legacyBlockJoints;
  const extraBlockStructureSurfaceM2 = extraBlockVerticalPanels > 0
    ? (extraBlockVerticalPanels * depthMm * bodyHeightMm) / 1_000_000
    : 0;
  const structureUnitPriceM2 = finish
    ? (Number(finish.price_chf) || 0) / ((finish.width_mm || 2800) * (finish.height_mm || 2070) / 1_000_000)
    : 0;
  const blockExtraStructureChf = Math.round(extraBlockStructureSurfaceM2 * structureUnitPriceM2 * 100) / 100;

  // Empilage vertical PAR COLONNE: chaque jonction d'une colonne empilée ajoute 2 panneaux
  // horizontaux (dessus du block inférieur + fond du block supérieur) à sa largeur intérieure.
  let stackExtraStructureSurfaceM2 = 0;
  if (stackEnabled) {
    if (useModules) {
      (modules || []).forEach((m, i) => {
        const colW = Math.max(0, (Number(m?.widthMm) || widthMm / Math.max(1, modules.length)) - 2 * PANEL.structure);
        if (resolvedHorizontalSpans.length === 0) {
          const joints = Math.max(0, columnBlockCounts[i] - 1);
          stackExtraStructureSurfaceM2 += (joints * 2 * colW * depthMm) / 1_000_000;
          return;
        }
        const boundaries = [0];
        columnBlockHeights[i].forEach((height) => boundaries.push(boundaries[boundaries.length - 1] + height));
        for (let boundaryIndex = 1; boundaryIndex < boundaries.length - 1; boundaryIndex++) {
          const boundaryMm = boundaries[boundaryIndex];
          const spanAtBottom = resolvedHorizontalSpans.some((span) =>
            span.moduleIndexes.includes(i) && Math.abs(span.bottomMm - boundaryMm) <= 0.5
          );
          const spanAtTop = resolvedHorizontalSpans.some((span) =>
            span.moduleIndexes.includes(i) && Math.abs(span.topMm - boundaryMm) <= 0.5
          );
          const retainedFaces = 2 - Number(spanAtBottom) - Number(spanAtTop);
          stackExtraStructureSurfaceM2 += (retainedFaces * colW * depthMm) / 1_000_000;
        }
      });
    } else {
      stackExtraStructureSurfaceM2 = (2 * Math.max(0, widthMm - 2 * PANEL.structure) * depthMm) / 1_000_000;
    }
  }
  if (resolvedHorizontalSpans.length > 0) {
    for (const span of resolvedHorizontalSpans) {
      const spanPanelWidthMm = Math.max(0, span.widthMm - 2 * PANEL.structure);
      stackExtraStructureSurfaceM2 += (2 * spanPanelWidthMm * depthMm) / 1_000_000;
      if (span.span?.hasBack) {
        // Back panels are 8 mm; price their surface proportionally to the 19 mm structure rate.
        stackExtraStructureSurfaceM2 +=
          (spanPanelWidthMm * Math.max(0, span.topMm - span.bottomMm - 2 * PANEL.structure)) /
          1_000_000 *
          (PANEL.back / PANEL.structure);
      }
    }
  }
  const stackExtraStructureChf = Math.round(stackExtraStructureSurfaceM2 * structureUnitPriceM2 * 100) / 100;

  // Each reinforcement is 100mm × innerDepth × 16mm — price as fraction of a panel
  const reinforcementSurfaceM2 = (PANEL.reinforcementWidth * (depthMm - PANEL.structure - 20)) / 1_000_000 * reinforcementCount;
  // Use 50% of panel price per m² for 16mm material (thinner, cheaper)
  const reinforcementUnitPriceM2 = finish ? (Number(finish.price_chf) || 0) * 0.5 / ((finish.width_mm || 2800) * (finish.height_mm || 2070) / 1_000_000) : 0;
  const reinforcementChf = Math.round(reinforcementSurfaceM2 * reinforcementUnitPriceM2 * 100) / 100;

  let optionsChf = 0;
  const services = data.serviceOptions || [];
  for (const optId of serviceOptionIds) {
    const opt = services.find((s) => s.id === optId || s.code === optId);
    if (opt) optionsChf += Number(opt.price_chf) || 0;
  }

  const totalChf = blocksChf + kitFeeChf + panelsChf + optionsChf + hardwareChf + reinforcementChf + blockExtraStructureChf + stackExtraStructureChf;

  return {
    totalChf: Math.round(totalChf * 100) / 100,
    surfaceM2: Math.round(surfaceM2 * 1000) / 1000,
    details: {
      blocksChf,
      modulesBreakdown,
      kitChf: kitFeeChf,
      panelsChf,
      reinforcementChf,
      reinforcementCount,
      columnMode,
      verticalStructurePanelCount,
      blockExtraStructureChf,
      stackExtraStructureChf,
      stackEnabled,
      stackedColumnCount: columnBlockCounts.filter((n) => n >= 2).length,
      optionsChf,
      hardwareChf,
      hardwareBreakdown,
      panelOptimization
    },
    warnings: isHandleAxisNonStandard
      ? [{ field: 'handleBoreHeightMm', message: `Hauteur perçage poignée hors plage standard (${minStandard}-${maxStandard} mm).` }]
      : undefined,
    errors: errors.length ? errors : undefined
  };
}

export default { 
  calculatePrice, 
  calculateVisibleSurface, 
  panelCost, 
  findOptimalDimension,
  calculateModuleCosts,
  calculateHardwareCosts
};