From 8fb0dd7ccac1e50cda5fee5cb9131078697bde97 Mon Sep 17 00:00:00 2001
From: Alexander Drozdov <snosme@gmail.com>
Date: Sat, 9 Oct 2021 15:01:09 +0300
Subject: [PATCH] fix some rounding

---
 src/web/map-check/prepare-map-stats.ts         |  4 ++--
 src/web/price-check/filters/SourceInfo.vue     |  4 ++--
 .../price-check/filters/create-stat-filters.ts |  4 ++--
 src/web/price-check/filters/util.ts            | 18 ++++++++++++------
 4 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/src/web/map-check/prepare-map-stats.ts b/src/web/map-check/prepare-map-stats.ts
index 02bad061..ad6493c1 100644
--- a/src/web/map-check/prepare-map-stats.ts
+++ b/src/web/map-check/prepare-map-stats.ts
@@ -1,6 +1,6 @@
 import { statSourcesTotal, translateStatWithRoll } from '@/parser/modifiers'
 import { ParsedItem } from '@/parser/ParsedItem'
-import { percentRoll } from '../price-check/filters/util'
+import { roundRoll } from '../price-check/filters/util'
 
 export interface PreparedStat {
   matcher: string
@@ -14,7 +14,7 @@ export function prepareMapStats (item: ParsedItem): PreparedStat[] {
 
     const prepared = {
       matcher: translation.string,
-      roll: roll && percentRoll(roll.value, 0, Math.floor, translation.dp)
+      roll: roll && roundRoll(roll.value, translation.dp ?? false)
     }
 
     if (translation.negate) {
diff --git a/src/web/price-check/filters/SourceInfo.vue b/src/web/price-check/filters/SourceInfo.vue
index 04655757..75ea6b14 100644
--- a/src/web/price-check/filters/SourceInfo.vue
+++ b/src/web/price-check/filters/SourceInfo.vue
@@ -13,7 +13,7 @@ import { computed, defineComponent, PropType } from 'vue'
 import { useI18n } from 'vue-i18n'
 import type { StatCalculated } from '@/parser/modifiers'
 import { applyIncr } from '@/parser/advanced-mod-desc'
-import { percentRoll } from './util'
+import { roundRoll } from './util'
 import ItemModifierText from '@/web/ui/ItemModifierText.vue'
 
 export default defineComponent({
@@ -69,7 +69,7 @@ export default defineComponent({
         const rollValue = parsed.roll.value * (parsed.translation.negate ? -1 : 1)
         return {
           text: parsed.translation.string,
-          roll: percentRoll(rollValue, 0, Math.floor, parsed.roll.dp),
+          roll: roundRoll(rollValue, parsed.roll.dp),
           contribution: contribution!,
           contributes: true
         }
diff --git a/src/web/price-check/filters/create-stat-filters.ts b/src/web/price-check/filters/create-stat-filters.ts
index e82820c9..789f8a4c 100644
--- a/src/web/price-check/filters/create-stat-filters.ts
+++ b/src/web/price-check/filters/create-stat-filters.ts
@@ -1,7 +1,7 @@
 import { ParsedItem, ItemRarity, ItemCategory } from '@/parser'
 import { ModifierType, StatCalculated, StatRoll, statSourcesTotal, translateStatWithRoll } from '@/parser/modifiers'
 import { uniqueModFilterPartial } from './unique-roll'
-import { rollToFilter, percentRoll } from './util'
+import { rollToFilter, percentRoll, roundRoll } from './util'
 import { FilterTag, ItemHasEmptyModifier, StatFilter } from './interfaces'
 import { filterPseudo } from './pseudo'
 import { filterItemProp } from './pseudo/item-property'
@@ -152,7 +152,7 @@ function itemModFilterPartial (
   if (roll) {
     if (calc.type === ModifierType.Enchant) {
       filter.roll = {
-        value: percentRoll(roll.value, 0, Math.floor, dp),
+        value: roundRoll(roll.value, dp),
         min: percentRoll(roll.value, 0, Math.floor, dp),
         max: percentRoll(roll.value, 0, Math.ceil, dp),
         default: {
diff --git a/src/web/price-check/filters/util.ts b/src/web/price-check/filters/util.ts
index 5a1c6f5c..96dc4e0b 100644
--- a/src/web/price-check/filters/util.ts
+++ b/src/web/price-check/filters/util.ts
@@ -1,26 +1,32 @@
 import type { StatFilter } from './interfaces'
 
-function showDecimals (value: number, dp: number | boolean): number {
+function decimalPlaces (value: number, dp: number | boolean): number {
   if (typeof dp === 'number') {
     return dp
-  } else if (!dp || Math.abs(value) > 2) {
+  } else if (!dp || Math.abs(value) >= 10) {
     return 0
   } else {
-    return Math.abs(value) < 1 ? 2 : 1
+    return Math.abs(value) < 2 ? 2 : 1
   }
 }
 
+export function roundRoll (value: number, dp: number | boolean) {
+  const round = Math.pow(10, decimalPlaces(value, dp))
+  // round value down (toward zero)
+  return Math.trunc(value * round) / round
+}
+
 export function percentRoll (value: number, p: number, method: Math['floor'] | Math['ceil'], dp: number | boolean = false): number {
   const res = value + value * p / 100
 
-  const rounding = Math.pow(10, showDecimals(value, dp))
+  const rounding = Math.pow(10, decimalPlaces(value, dp))
   return method((res + Number.EPSILON) * rounding) / rounding
 }
 
 export function percentRollDelta (value: number, delta: number, p: number, method: Math['floor'] | Math['ceil'], dp = false): number {
   const res = value + delta * p / 100
 
-  const rounding = Math.pow(10, showDecimals(value, dp))
+  const rounding = Math.pow(10, decimalPlaces(value, dp))
   return method((res + Number.EPSILON) * rounding) / rounding
 }
 
@@ -34,7 +40,7 @@ export function rollToFilter (
   // disabled by default, so opts.neverNegated acts more like
   // acknowledgment of what you are doing
   return {
-    value: percentRoll(roll, 0, Math.floor, dp),
+    value: roundRoll(roll, dp ?? false),
     default: {
       min: percentRoll(roll, -percent * Math.sign(roll), Math.floor, dp),
       max: percentRoll(roll, +percent * Math.sign(roll), Math.ceil, dp)