package diablo2item import ( "github.com/OpenDiablo2/OpenDiablo2/d2common/d2data/d2datadict" "math/rand" "regexp" "strconv" ) const ( DropModifierBaseProbability = 1024 // base DropModifier probability total ) type DropModifier int const ( DropModifierNone DropModifier = iota DropModifierUnique DropModifierSet DropModifierRare DropModifierMagic ) const ( // DynamicItemLevelRange for treasure codes like `armo33`, this code is used to // select all equivalent items (matching `armo` in this case) with item levels 33,34,35 DynamicItemLevelRange = 3 ) const ( goldItemCodeWithMult = "gld,mul=" goldItemCode = "gld" ) // ItemGenerator is a diablo 2 implementation of an item generator type ItemGenerator struct { rand *rand.Rand source rand.Source Seed int64 } // SetSeed sets the item generator seed func (ig *ItemGenerator) SetSeed(seed int64) { if ig.rand == nil || ig.source == nil { ig.source = rand.NewSource(seed) ig.rand = rand.New(ig.source) } ig.Seed = seed } func (ig *ItemGenerator) rollDropModifier(tcr *d2datadict.TreasureClassRecord) DropModifier { modMap := map[int]DropModifier{ 0: DropModifierNone, 1: DropModifierUnique, 2: DropModifierSet, 3: DropModifierRare, 4: DropModifierMagic, } dropModifiers := []int{ DropModifierBaseProbability, tcr.FreqUnique, tcr.FreqSet, tcr.FreqRare, tcr.FreqMagic, } for idx := range dropModifiers { if idx == 0 { continue } dropModifiers[idx] += dropModifiers[idx-1] } roll := ig.rand.Intn(dropModifiers[len(dropModifiers)-1]) for idx := range dropModifiers { if roll < dropModifiers[idx] { return modMap[idx] } } return DropModifierNone } func (ig *ItemGenerator) rollTreasurePick(tcr *d2datadict.TreasureClassRecord) *d2datadict.Treasure { // treasure probabilities tprob := make([]int, len(tcr.Treasures)+1) total := tcr.FreqNoDrop tprob[0] = total for idx := range tcr.Treasures { total += tcr.Treasures[idx].Probability tprob[idx+1] = total } roll := ig.rand.Intn(total) for idx := range tprob { if roll < tprob[idx] { if idx == 0 { break } return tcr.Treasures[idx-1] } } return nil } // ItemsFromTreasureClass rolls for and creates items using a treasure class record func (ig *ItemGenerator) ItemsFromTreasureClass(tcr *d2datadict.TreasureClassRecord) []*Item { result := make([]*Item, 0) treasurePicks := make([]*d2datadict.Treasure, 0) // if tcr.NumPicks is negative, each item probability is instead a count for how many // of that treasure to drop if tcr.NumPicks < 0 { picksLeft := tcr.NumPicks // for each of the treasures, we pick it N times, where N is the count for the item // we do this until we run out of picks for idx := range tcr.Treasures { howMany := tcr.Treasures[idx].Probability for count := 0; count < howMany && picksLeft < 0; count++ { treasurePicks = append(treasurePicks, tcr.Treasures[idx]) picksLeft++ } } } else { // for N picks, we roll for a treasure and append to our treasures if it isn't a NoDrop for picksLeft := tcr.NumPicks; picksLeft > 0; picksLeft-- { rolledTreasure := ig.rollTreasurePick(tcr) if rolledTreasure == nil { continue } treasurePicks = append(treasurePicks, rolledTreasure) } } // for each of our picked/rolled treasures, we will attempt to generate an item. // The treasure may actually be a reference to another treasure class, in which // case we will roll that treasure class, eventually getting a slice of items for idx := range treasurePicks { picked := treasurePicks[idx] if record, found := d2datadict.TreasureClass[picked.Code]; found { // the code is for a treasure class, we roll again using that TC itemSlice := ig.ItemsFromTreasureClass(record) for itemIdx := range itemSlice { itemSlice[itemIdx].applyDropModifier(ig.rollDropModifier(tcr)) itemSlice[itemIdx].generateAllProperties() itemSlice[itemIdx].updateItemAttributes() result = append(result, itemSlice[itemIdx]) } } else { // the code is not for a treasure class, but for an item item := ig.ItemFromTreasure(picked) if item != nil { item.applyDropModifier(ig.rollDropModifier(tcr)) item.generateAllProperties() item.updateItemAttributes() result = append(result, item) } } } return result } // ItemFromTreasure rolls for a ig.rand.m item using the Treasure struct (from d2datadict) func (ig *ItemGenerator) ItemFromTreasure(treasure *d2datadict.Treasure) *Item { result := &Item{ rand: rand.New(rand.NewSource(ig.Seed)), } // in this case, the treasure code is a code used by an ItemCommonRecord commonRecord := d2datadict.CommonItems[treasure.Code] if commonRecord != nil { result.CommonCode = commonRecord.Code return result } // next, we check if the treasure code is a generic type like `armo` equivList := d2datadict.ItemEquivalenciesByTypeCode[treasure.Code] if equivList != nil { result.CommonCode = equivList[ig.rand.Intn(len(equivList))].Code return result } // in this case, the treasure code is something like `armo23` and needs to // be resolved to ItemCommonRecords for armors with levels 23,24,25 matches := resolveDynamicTreasureCode(treasure.Code) if matches != nil { numItems := len(matches) if numItems < 1 { return nil } result.CommonCode = matches[ig.rand.Intn(numItems)].Code return result } return nil } func resolveDynamicTreasureCode(code string) []*d2datadict.ItemCommonRecord { numericComponent := getNumericComponent(code) stringComponent := getStringComponent(code) if stringComponent == goldItemCodeWithMult { // todo need to do something with the numeric component (the gold multiplier) stringComponent = goldItemCode } result := make([]*d2datadict.ItemCommonRecord, 0) equivList := d2datadict.ItemEquivalenciesByTypeCode[stringComponent] for idx := range equivList { record := equivList[idx] minLevel := numericComponent maxLevel := minLevel + DynamicItemLevelRange if record.Level >= minLevel && record.Level < maxLevel { result = append(result, record) } } return result } func getStringComponent(code string) string { re := regexp.MustCompile(`\d+`) return string(re.ReplaceAll([]byte(code), []byte(""))) } func getNumericComponent(code string) int { result := 0 re := regexp.MustCompile(`[^\d]`) numStr := string(re.ReplaceAll([]byte(code), []byte(""))) if number, err := strconv.ParseInt(numStr, 10, 32); err == nil { result = int(number) } return result }