/**
 * Moteur de calcul de prix — configurateur armoires sur mesure.
 * Règles : panneaux entiers (chute intégrée), blocs, kit, options.
 */

/**
 * Calcule la surface utile des éléments visibles (portes, fileurs, bandeau, plinthe, côtés doublage).
 * Épaisseur panneaux 19 mm (référence).
 * @param {Object} config - configuration (installation, width, height, depth, plinthHeightMm, blocks, doorType, slidingPanels)
 * @param {number} panelThicknessMm - épaisseur panneaux (19)
 */
function calculateVisibleSurface(config, panelThicknessMm = 19) {
  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 {
    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)
  surface += widthMm * plinthHeightMm;

  // 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
 */
function calculateHardwareCosts(hardware, hardwareData, config) {
  const { handles = [], hinges = [], blum = [] } = hardwareData;
  const breakdown = [];
  let totalChf = 0;
  
  // Handle costs - one per door
  if (hardware.handleVariantId) {
    const handle = handles.find(h => h.id === hardware.handleVariantId);
    if (handle) {
      const doorCount = config.doorType === 'sliding' 
        ? (config.slidingPanelsCount || 2)
        : (config.modules?.length || config.blocks?.length || 2);
      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 - typically 3 per hinged door
  if (hardware.hingeVariantId && config.doorType !== 'sliding') {
    const hinge = hinges.find(h => h.id === hardware.hingeVariantId);
    if (hinge) {
      const doorCount = config.modules?.length || config.blocks?.length || 2;
      const hingesPerDoor = 3;
      const quantity = doorCount * hingesPerDoor;
      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 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 = Number(settings.kit_preparation_fee_chf) ?? 350;
  const plinthMin = Number(settings.plinth_height_min_mm) ?? 60;
  const plinthMax = Number(settings.plinth_height_max_mm) ?? 160;
  const slidingMinWidth = Number(settings.sliding_doors_min_width_mm) ?? 1200;

  const { 
    installationType, widthMm, heightMm, depthMm, plinthHeightMm, 
    blocks = [], modules = [], hardware = {},
    doorType, slidingPanelsCount, finishId, serviceOptionIds = [] 
  } = config;

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

  // Plinthe 60–160 mm
  if (plinthHeightMm < plinthMin || plinthHeightMm > plinthMax) {
    errors.push({ field: 'plinthHeightMm', message: `La hauteur de plinthe doit être entre ${plinthMin} et ${plinthMax} 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' && (slidingPanelsCount < 2 || slidingPanelsCount > 3)) {
    errors.push({ field: 'slidingPanelsCount', message: 'Choisissez 2 ou 3 vantaux coulissants.' });
  }

  // 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).` });
    }
  } 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: []
      };
    }
  }

  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;

  return {
    totalChf: Math.round(totalChf * 100) / 100,
    surfaceM2: Math.round(surfaceM2 * 1000) / 1000,
    details: {
      blocksChf,
      modulesBreakdown,
      kitChf: kitFeeChf,
      panelsChf,
      optionsChf,
      hardwareChf,
      hardwareBreakdown,
      panelOptimization
    },
    errors: errors.length ? errors : undefined
  };
}

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