mojang cant get their cases straight

i had to implement like 4 cases just  to parse that file

level/anvil/level.go

@@ -7,18 +7,179 @@ import (
 )
 
 type Level struct {
-	DataPacks struct {
+	ClearWeatherTime           int32 `nbt:"clearWeatherTime"`
+	DataPacks                  DataPacks
+	DayTime                    int64
+	WanderingTraderSpawnChance int32
+	GameType                   int32
+	WorldGenSettings           WorldGenSettings
+	ScheduledEvents            []interface{}
+	WasModded                  bool
+	ThunderTime                int32 `nbt:"thunderTime"`
+	Difficulty                 int8
+	DragonFight                DragonFight
+	Initialized                bool
+	AllowCommands              bool `nbt:"allowCommands"`
+	Thundering                 bool
+	LastPlayed                 int64
+	GameRules                  map[string]interface{}
+	RainTime                   int32 `nbt:"rainTime"`
+	DataVersion                int32
+	Version                    Version
+	WanderingTraderSpawnDelay  int32
+	Hardcore                   bool
+	Spawn                      Spawn
+	Raining                    bool
+	Player                     Player
+	DifficultyLocked           bool
+	LevelName                  string
+	Time                       int64
+	ServerBrands               []string
+	CustomBossEvents           map[string]interface{}
+}
+
+type DataPacks struct {
 	Enabled  []string
 	Disabled []string
-	}
+}
+
+type WorldGenSettings struct {
+	BonusChest       bool
+	Seed             int64
+	GenerateFeatures bool
+	Dimensions       map[string]Dimension
+}
+
+type Dimensions struct {
+	Overworld Dimension
+	Nether    Dimension
+	End       Dimension
+}
+
+type Dimension struct {
+	Generator Generator
+	Type      string
+}
+
+type Generator struct {
+	Type        string
+	Settings    string
+	BiomeSource BiomeSource
+}
+
+type BiomeSource struct {
+	Preset string `nbt:"preset,omitempty"`
+	Type   string
+}
+
+type DragonFight struct {
+	NeedsStateScanning bool
+	Gateways           []int32
+	DragonKilled       bool
+	PreviouslyKilled   bool
+}
+
+type Version struct {
+	Snapshot bool
+	Series   string
+	Id       int32
+	Name     string
+}
+
+type Spawn struct {
+	Dimension string
+	Yaw       float32
+	Pos       [3]int32
+	Pitch     float32
+}
+
+type Player struct {
+	XpLevel                              int32
+	HurtTime                             int16
+	DeathTime                            int16
+	XpTotal                              int32
+	FoodExhaustionLevel                  float32
+	RecipeBook                           RecipeBook
+	Fire                                 int16
+	Brain                                Brain
+	XpSeed                               int32
+	XpP                                  float32
+	EnderItems                           []interface{}
+	Invulnerable                         bool
+	Pos                                  [3]float64
+	Inventory                            []InventoryItem
+	SleepTimer                           int16
+	Abilities                            Abilities
+	PlayerGameType                       int32
+	SeenCredits                          bool
+	FoodSaturationLevel                  float32
+	FallDistance                         float64
+	OnGround                             bool
+	Dimension                            string
+	PortalCooldown                       int32
+	Motion                               [3]float64
+	IgnoreFallDamageFromCurrentExplosion bool
+	Rotation                             [2]float32
+	CurrentImpulseContextResetGraceTime  int32
+	WardenSpawnTracker                   WardenSpawnTracker
+	PreviousPlayerGameType               int32
+	Attributes                           []Attribute
+	HurtByTimestamp                      int32
+	UUID                                 [4]int32
+	Score                                int32
+	DataVersion                          int32
+	FoodLevel                            int32
+	SpawnExtraParticlesOnFall            bool
+	SelectedItemSlot                     int32
+	FoodTickTimer                        int32
+	FallFlying                           bool
+	AbsorptionAmount                     float32
+	Health                               float32
+	Air                                  int16
+}
+
+type RecipeBook struct {
+	Recipes       []string
+	ToBeDisplayed []string
+}
+
+type Brain struct {
+	Memories map[string]interface{}
+}
+
+type InventoryItem struct {
+	Count int32
+	Slot  int8
+	Id    string
+}
+
+type Abilities struct {
+	Invulnerable bool
+	Mayfly       bool
+	Instabuild   bool
+	WalkSpeed    float32
+	MayBuild     bool
+	Flying       bool
+	FlySpeed     float32
+}
+
+type WardenSpawnTracker struct {
+	WarningLevel          int32
+	TicksSinceLastWarning int32
+	CooldownTicks         int32
+}
+
+type Attribute struct {
+	Id   string
+	Base float64
 }
 
 func ReadLevelData(r io.Reader) (l Level, err error) {
-	var lDtatWrapped struct{ Data Level }
+	var lDataWrapped struct{ Data Level }
-	err = nbt.ReadFile(r, &lDtatWrapped)
+	err = nbt.ReadFile(r, &lDataWrapped)
 	if err != nil {
 		return
 	}
-	l = lDtatWrapped.Data
+	l = lDataWrapped.Data
 	return
 }

mapstructure/decode.go

@@ -3,6 +3,8 @@ package mapstructure
 import (
 	"fmt"
 	"reflect"
+
+	"github.com/admin-else/strom/util"
 )
 
 func (f *Format) decode(m map[string]any, target reflect.Value) error {
@@ -26,12 +28,19 @@ func (f *Format) decode(m map[string]any, target reflect.Value) error {
 		}
 
 		val, exists := m[key]
+		if !exists && f.trySnakeCase {
+			val, exists = m[util.SnakeCase(key)]
+		}
+		if !exists && f.tryLowCase {
+			val, exists = m[util.FirstLetterLower(key)]
+		}
 		if !exists {
 			if tag.Required || (f.requireAll && !tag.OmitEmpty) {
 				return fmt.Errorf("%w: %s", ErrMissingRequired, key)
 			}
 			continue
 		}
+
 		usedKeys[key] = true
 
 		fieldVal := target.Field(i)
@@ -108,6 +117,26 @@ func (f *Format) setField(target reflect.Value, value any, opts tagOptions) erro
 		return f.setBool(target, value)
 	}
 
+	// this fixes this edge case
+	//     level_test.go:19: field Data: field Player: field Pos: cannot set [3]float64 from []interface {}
+	if targetType.Kind() == reflect.Array && src.Kind() == reflect.Slice {
+		if target.Len() != src.Len() {
+			return fmt.Errorf("cannot set %s from %T because lengths do not match", targetType, value)
+		}
+		for i := 0; i < src.Len(); i++ {
+			if src.Index(i).Type().AssignableTo(targetType.Elem()) {
+				target.Index(i).Set(src.Index(i))
+				continue
+			}
+			if src.Index(i).Elem().Type().AssignableTo(targetType.Elem()) {
+				target.Index(i).Set(src.Index(i).Elem())
+				continue
+			}
+			return fmt.Errorf("cannot set %s from %T because element %d cannot be converted to %s", targetType, value, i, targetType.Elem())
+		}
+		return nil
+	}
+
 	return fmt.Errorf("cannot set %s from %T", targetType, value)
 }
 

mapstructure/format.go

@@ -18,6 +18,9 @@ type Format struct {
 	Name         string
 	requireAll   bool
 	errorOnExtra bool
+	trySnakeCase bool
+	tryLowCase   bool
+
 	decoders map[reflect.Type]func(any, string) (any, error)
 	encoders map[reflect.Type]func(any, string) (any, error)
 }
@@ -48,6 +51,18 @@ func WithErrorOnExtra() Option {
 	}
 }
 
+func WithTrySnakeCase() Option {
+	return func(f *Format) {
+		f.trySnakeCase = true
+	}
+}
+
+func WithTryLowCase() Option {
+	return func(f *Format) {
+		f.tryLowCase = true
+	}
+}
+
 func WithTypeCodec(decodeFn, encodeFn any) Option {
 	dt := reflect.TypeOf(decodeFn)
 	et := reflect.TypeOf(encodeFn)

nbt/file.go

@@ -8,7 +8,7 @@ import (
 	"github.com/admin-else/strom/mapstructure"
 )
 
-var Format = mapstructure.NewFormat("nbt", mapstructure.WithRequireAll())
+var Format = mapstructure.NewFormat("nbt", mapstructure.WithRequireAll(), mapstructure.WithTrySnakeCase(), mapstructure.WithTryLowCase())
 
 func ReadFile(file io.Reader, data any) (err error) {
 	n, err := ReadUnstructuredFile(file)

proto_generator/utils.go

@@ -4,28 +4,8 @@ import (
 	"cmp"
 	"maps"
 	"slices"
-	"unicode"
 )
 
-var boundaries = []rune{' ', '_', '-', '.', ',', ';', ':', '(', ')', '[', ']', '{', '}'}
-
-func CamelCase(s string) string {
-	ret := ""
-	atWordBoundary := true
-	for _, c := range s {
-		if slices.Contains(boundaries, c) {
-			atWordBoundary = true
-			continue
-		}
-		if atWordBoundary && unicode.IsLower(c) {
-			c = unicode.ToUpper(c)
-		}
-		atWordBoundary = false
-		ret += string(c)
-	}
-	return ret
-}
-
 func OrderedKeys[Map map[K]V, K cmp.Ordered, V any](m Map) []K {
 	keysIter := maps.Keys(m)
 	keys := slices.Collect(keysIter)

util/case.go

@@ -0,0 +1,43 @@
+package util
+
+import (
+	"slices"
+	"unicode"
+)
+
+var boundaries = []rune{' ', '_', '-', '.', ',', ';', ':', '(', ')', '[', ']', '{', '}'}
+
+func CamelCase(s string) string {
+	ret := ""
+	atWordBoundary := true
+	for _, c := range s {
+		if slices.Contains(boundaries, c) {
+			atWordBoundary = true
+			continue
+		}
+		if atWordBoundary && unicode.IsLower(c) {
+			c = unicode.ToUpper(c)
+		}
+		atWordBoundary = false
+		ret += string(c)
+	}
+	return ret
+}
+
+func SnakeCase(s string) string {
+	ret := ""
+	for i, c := range s {
+		if unicode.IsUpper(c) {
+			if i > 0 {
+				ret += "_"
+			}
+			c = unicode.ToLower(c)
+		}
+		ret += string(c)
+	}
+	return ret
+}
+
+func FirstLetterLower(s string) string {
+	return string(unicode.ToLower(rune(s[0]))) + s[1:]
+}

util/case_test.go

@@ -1,6 +1,10 @@
-package main
+package util_test
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/admin-else/strom/util"
+)
 
 func TestCamelCase(t *testing.T) {
 	tests := []struct {
@@ -17,7 +21,7 @@ func TestCamelCase(t *testing.T) {
 	}
 
 	for _, test := range tests {
-		result := CamelCase(test.input)
+		result := util.CamelCase(test.input)
 		if result != test.expected {
 			t.Errorf("CamelCase(%q) = %q; expected %q", test.input, result, test.expected)
 		}