oil-formula-calculator/frontend/src/composables/useKitCost.js

import { computed } from 'vue'
import { useOilsStore } from '../stores/oils'
import { useRecipesStore } from '../stores/recipes'
import { KITS } from '../config/kits'

/**
 * 套装成本分摊与配方匹配
 *
 * 分摊逻辑：按各精油原瓶价占比分摊套装总价
 *   某精油套装内成本 = (该油原瓶价 / 套装内所有油原瓶价之和) × 套装总价
 *   套装内每滴成本 = 套装内成本 / 该油滴数
 */
export function useKitCost() {
  const oils = useOilsStore()
  const recipeStore = useRecipesStore()

  // Resolve kit oil name to system oil name (handles 牛至→西班牙牛至 etc.)
  function resolveOilName(kitOilName) {
    if (oils.oilsMeta[kitOilName]) return kitOilName
    // Try finding system oil that ends with kit name
    return oils.oilNames.find(n => n.endsWith(kitOilName) && n !== kitOilName) || kitOilName
  }

  // Calculate per-drop costs for a kit
  function calcKitPerDrop(kit) {
    const resolved = kit.oils.map(name => resolveOilName(name))
    const bc = kit.bottleCount || {} // e.g. { '椰子油': 2.57 }
    // Sum of bottle prices for all oils in kit (accounting for multiple bottles)
    let totalBottlePrice = 0
    const oilBottlePrices = {}
    for (const name of resolved) {
      const meta = oils.oilsMeta[name]
      const count = bc[name] || 1
      const bp = meta ? meta.bottlePrice * count : 0
      oilBottlePrices[name] = bp
      totalBottlePrice += bp
    }
    if (totalBottlePrice === 0) return {}

    // Uniform discount: kit price covers oils + accessories at the same discount rate
    // discount_rate = kit_price / (oil_total + accessory_value)
    // each oil's kit cost = bottle_price × discount_rate
    const totalValue = totalBottlePrice + (kit.accessoryValue || 0)
    const discountRate = Math.min(kit.price / totalValue, 1) // cap at 1 (no markup)
    const perDrop = {}
    for (const name of resolved) {
      const meta = oils.oilsMeta[name]
      const count = bc[name] || 1
      const bp = oilBottlePrices[name]
      const kitCostForOil = bp * discountRate
      const totalDrops = meta ? meta.dropCount * count : 1
      perDrop[name] = totalDrops > 0 ? kitCostForOil / totalDrops : 0
    }
    return perDrop
  }

  // Check if a recipe can be made with a kit
  function canMakeRecipe(kit, recipe) {
    const resolvedSet = new Set(kit.oils.map(name => resolveOilName(name)))
    return recipe.ingredients.every(ing => resolvedSet.has(ing.oil))
  }

  // Calculate recipe cost using kit pricing
  function calcRecipeCostWithKit(kitPerDrop, recipe) {
    return recipe.ingredients.reduce((sum, ing) => {
      const ppd = kitPerDrop[ing.oil] || 0
      return sum + ppd * ing.drops
    }, 0)
  }

  // Get all matching recipes for a kit
  function getKitRecipes(kit) {
    const perDrop = calcKitPerDrop(kit)
    return recipeStore.recipes
      .filter(r => canMakeRecipe(kit, r))
      .map(r => ({
        ...r,
        kitCost: calcRecipeCostWithKit(perDrop, r),
        originalCost: oils.calcCost(r.ingredients),
      }))
      .sort((a, b) => a.name.localeCompare(b.name, 'zh'))
  }

  // Build full analysis for all kits, sorted by recipe count ascending (fewest recipes first)
  const kitAnalysis = computed(() => {
    return KITS.map(kit => {
      const perDrop = calcKitPerDrop(kit)
      const recipes = getKitRecipes(kit)
      // Calculate discount rate for display
      const resolved = kit.oils.map(name => resolveOilName(name))
      const bc = kit.bottleCount || {}
      let totalBP = 0
      for (const name of resolved) {
        const meta = oils.oilsMeta[name]
        totalBP += meta ? meta.bottlePrice * (bc[name] || 1) : 0
      }
      const totalValue = totalBP + (kit.accessoryValue || 0)
      const discountRate = totalValue > 0 ? Math.min(kit.price / totalValue, 1) : 1

      return {
        ...kit,
        perDrop,
        recipes,
        recipeCount: recipes.length,
        discountRate,
      }
    }).sort((a, b) => a.recipeCount - b.recipeCount)
  })

  // Cross-kit comparison: membership-tier style
  // Columns: kits ordered by recipe count (fewest→most, from kitAnalysis)
  // Rows: recipes available to most kits at top, exclusive recipes at bottom (staircase pattern)
  const crossComparison = computed(() => {
    const analysis = kitAnalysis.value
    // Kit order for staircase: index in sorted analysis (0 = smallest kit)
    const kitOrder = analysis.map(ka => ka.id)

    const allRecipeIds = new Set()
    for (const ka of analysis) {
      for (const r of ka.recipes) allRecipeIds.add(r._id)
    }

    const rows = []
    for (const id of allRecipeIds) {
      let recipe = null
      const costs = {}
      let availCount = 0
      // Track which kit columns have this recipe (by index in sorted order)
      let smallestKitIdx = kitOrder.length
      for (let i = 0; i < analysis.length; i++) {
        const ka = analysis[i]
        const found = ka.recipes.find(r => r._id === id)
        if (found) {
          if (!recipe) recipe = found
          costs[ka.id] = found.kitCost
          availCount++
          if (i < smallestKitIdx) smallestKitIdx = i
        } else {
          costs[ka.id] = null
        }
      }
      rows.push({
        id,
        name: recipe.name,
        tags: recipe.tags,
        volume: recipe.volume,
        ingredients: recipe.ingredients,
        originalCost: recipe.originalCost,
        costs,
        availCount,
        smallestKitIdx,
      })
    }
    // Staircase sort: most available first, then by smallest kit that has it, then by name
    rows.sort((a, b) => {
      if (a.availCount !== b.availCount) return b.availCount - a.availCount
      if (a.smallestKitIdx !== b.smallestKitIdx) return a.smallestKitIdx - b.smallestKitIdx
      return a.name.localeCompare(b.name, 'zh')
    })
    return rows
  })

  return {
    KITS,
    resolveOilName,
    calcKitPerDrop,
    canMakeRecipe,
    calcRecipeCostWithKit,
    getKitRecipes,
    kitAnalysis,
    crossComparison,
  }
}