feat: improve bill math

feat: add escrow storage for aveiro and changes in related UI
feat: add cassettes and stackers count to trader

lib/bill-math.js

@@ -1,15 +1,112 @@
 const _ = require('lodash/fp')
 const sumService = require('@haensl/subset-sum')
 
-const getSolution = (units, amount) => {
-  const billList = _.reduce(
-    (acc, value) => {
-      acc.push(..._.times(_.constant(value.denomination), value.count))
-      return acc
-    },
-    [],
-    units
-  )
+const BILL_LIST_MODES = {
+  LAST_UNIT_FIRST: 0,
+  FIRST_UNIT_FIRST: 1,
+  LOWEST_VALUE_FIRST: 2,
+  HIGHEST_VALUE_FIRST: 3,
+  UNIT_ROUND_ROBIN: 4,
+  VALUE_ROUND_ROBIN: 5
+}
+
+const buildBillList = (units, mode) => {
+  switch (mode) {
+    case BILL_LIST_MODES.LAST_UNIT_FIRST:
+      return _.reduce(
+        (acc, value) => {
+          acc.push(..._.times(_.constant(value.denomination), value.count))
+          return acc
+        },
+        [],
+        _.reverse(units)
+      )
+    case BILL_LIST_MODES.FIRST_UNIT_FIRST:
+      return _.reduce(
+        (acc, value) => {
+          acc.push(..._.times(_.constant(value.denomination), value.count))
+          return acc
+        },
+        [],
+        units
+      )
+    case BILL_LIST_MODES.LOWEST_VALUE_FIRST:
+      return _.reduce(
+        (acc, value) => {
+          acc.push(..._.times(_.constant(value.denomination), value.count))
+          return acc
+        },
+        [],
+        _.orderBy(['denomination'], ['asc'])(units)
+      )
+    case BILL_LIST_MODES.HIGHEST_VALUE_FIRST:
+      return _.reduce(
+        (acc, value) => {
+          acc.push(..._.times(_.constant(value.denomination), value.count))
+          return acc
+        },
+        [],
+        _.orderBy(['denomination'], ['desc'])(units)
+      )
+    case BILL_LIST_MODES.UNIT_ROUND_ROBIN:
+      {
+        const amountOfBills = _.reduce(
+          (acc, value) => acc + value.count,
+          0,
+          units
+        )
+      
+        const _units = _.cloneDeep(units)
+        const bills = []
+      
+        for(let i = 0; i < amountOfBills; i++) {
+          const idx = i % _.size(_units)
+          if (_units[idx].count > 0) {
+            bills.push(_units[idx].denomination)
+          }
+      
+          _units[idx].count--
+      
+          if (_units[idx].count === 0) {
+            _units.splice(idx, 1)
+          }
+        }
+
+        return bills
+      }
+    case BILL_LIST_MODES.VALUE_ROUND_ROBIN:
+      {
+        const amountOfBills = _.reduce(
+          (acc, value) => acc + value.count,
+          0,
+          units
+        )
+      
+        const _units = _.orderBy(['denomination'], ['asc'])(_.cloneDeep(units))
+        const bills = []
+      
+        for(let i = 0; i < amountOfBills; i++) {
+          const idx = i % _.size(_units)
+          if (_units[idx].count > 0) {
+            bills.push(_units[idx].denomination)
+          }
+      
+          _units[idx].count--
+      
+          if (_units[idx].count === 0) {
+            _units.splice(idx, 1)
+          }
+        }
+
+        return bills
+      }
+    default:
+      throw new Error(`Invalid mode: ${mode}`)
+  }
+}
+
+const getSolution = (units, amount, mode) => {
+  const billList = buildBillList(units, mode)
   
   const solver = sumService.subsetSum(billList, amount.toNumber())
   const solution = _.countBy(Math.floor, solver.next().value)
@@ -39,7 +136,7 @@ const solutionToOriginalUnits = (solution, units) => {
 }
 
 function makeChange(outCassettes, amount) {
-  const solution = getSolution(outCassettes, amount)
+  const solution = getSolution(outCassettes, amount, BILL_LIST_MODES.VALUE_ROUND_ROBIN)
   return solutionToOriginalUnits(solution, outCassettes)
 }