ipsw/pkg/car/car.go

package car

import (
	"bufio"
	"bytes"
	"encoding/binary"
	"encoding/hex"
	"fmt"
	"image"
	"image/color"
	"image/png"
	"io"
	"os"
	"path/filepath"
	"strings"

	"github.com/apex/log"
	"github.com/blacktop/go-macho/types"
	"github.com/blacktop/go-termimg"
	"github.com/blacktop/ipsw/internal/utils"
	"github.com/blacktop/ipsw/pkg/bom"
)

// NOTES:
// - https://github.com/insidegui/AssetCatalogTinkerer
// - https://github.com/bartoszj/acextract
// - https://blog.timac.org/2018/1018-reverse-engineering-the-car-file-format/

type Config struct {
	Output  string
	Export  bool
	Verbose bool
}

type Asset struct {
	Header
	Metadata  extendedMetadata
	KeyFormat []renditionAttributeType
	ImageDB   []Rendition
	ColorDB   map[string]color.RGBA
	// FontDB        map[string]Font
	// FontSizeDB    map[string]uint32
	// GlyphDB       map[string]Glyph
	// BezelDB       map[string]Bezel
	FacetKeyDB    map[string]renditionKeyToken
	BitmapKeyDB   map[any][]byte
	AppearanceDB  map[string]uint16
	Globals       []byte // bplist data
	Localizations map[string]uint32

	conf *Config
}

func (a *Asset) GetName(id uint16) string {
	for k, v := range a.FacetKeyDB {
		for _, attr := range v.Attributes {
			if attr.Name == uint16(Identifier) && attr.Value == id {
				return k
			}
		}
	}
	return ""
}

func (a *Asset) GetFaceKey(id uint16) (*renditionKeyToken, error) {
	for _, v := range a.FacetKeyDB {
		for _, attr := range v.Attributes {
			if attr.Name == 17 && attr.Value == id {
				return &v, nil
			}
		}
	}
	return nil, fmt.Errorf("could not find face key for id: %d", id)
}

type Header struct {
	Tag                [4]byte // 'CTAR'
	CoreUiVersion      uint32
	StorageVersion     uint32
	StorageTimestamp   uint32
	RenditionCount     uint32
	MainVersionString  [128]byte
	VersionString      [256]byte
	UUID               types.UUID
	AssociatedChecksum uint32
	SchemaVersion      uint32
	ColorSpaceID       colorSpaceID
	KeySemantics       uint32
}

type extendedMetadata struct {
	Tag                       [4]byte // 'META'
	ThinningArguments         [256]byte
	DeploymentPlatformVersion [256]byte
	DeploymentPlatform        [256]byte
	AuthoringTool             [256]byte
}

type renditionAttributeType uint32

const (
	ThemeLook renditionAttributeType = iota
	Element
	Part
	Size
	Direction
	Placeholder
	Value
	ThemeAppearance
	Dimension1
	Dimension2
	State
	Layer
	Scale
	Localization
	PresentationState
	Idiom
	Subtype
	Identifier
	PreviousValue
	PreviousState
	HorizontalSizeClass
	VerticalSizeClass
	MemoryLevelClass
	GraphicsFeatureSetClass
	DisplayGamut
	DeploymentTarget
	GlyphWeight
	GlyphSize
)

type RenditionKeyformat struct {
	Tag                           [4]byte // 'kfmt'
	Version                       uint32
	MaximumRenditionKeyTokenCount uint32
	RenditionKeyTokens            []renditionAttributeType
}

type systemColor struct {
	Version uint32 // 1
	Unknown uint32 // 0
	Color   struct {
		Blue  uint8
		Green uint8
		Red   uint8
		Alpha uint8
	}
}

type renditionLayoutType uint16

const (
	OnePart             renditionLayoutType = 0
	ThreePartHorizontal renditionLayoutType = 1
	ThreePartVertical   renditionLayoutType = 2
	NinePart            renditionLayoutType = 3
	TwelvePart          renditionLayoutType = 4
	ManyPart            renditionLayoutType = 5
	Gradient            renditionLayoutType = 6
	Effect              renditionLayoutType = 7
	Animation           renditionLayoutType = 8
	Vector              renditionLayoutType = 9

	IconImage renditionLayoutType = 12

	Unknown renditionLayoutType = 20

	RawData             renditionLayoutType = 1000
	ExternalLink        renditionLayoutType = 1001
	ImageStack          renditionLayoutType = 1002
	InternalLink        renditionLayoutType = 1003
	PackedImage         renditionLayoutType = 1004
	NamedContents       renditionLayoutType = 1005
	ThinningPlaceholder renditionLayoutType = 1006
	TextureRendition    renditionLayoutType = 1007
	TextureImage        renditionLayoutType = 1008
	Color               renditionLayoutType = 1009
	MultiSizeImageSet   renditionLayoutType = 1010
	ModelIOAsset        renditionLayoutType = 1011
	ModelMesh           renditionLayoutType = 1012
	RecognitionGroup    renditionLayoutType = 1013
	RecognitionObject   renditionLayoutType = 1014

	ModelIOSubmesh  renditionLayoutType = 1016
	VectorGlyph     renditionLayoutType = 1017
	SolidImageStack renditionLayoutType = 1018
	IconImageStack  renditionLayoutType = 1019
	IconGroup       renditionLayoutType = 1020
	NamedGradient   renditionLayoutType = 1021
)

type coreThemeIdiom uint32

const (
	Universal coreThemeIdiom = 0
	Phone     coreThemeIdiom = 1
	Tablet    coreThemeIdiom = 2
	Desktop   coreThemeIdiom = 3
	Tv        coreThemeIdiom = 4
	Car       coreThemeIdiom = 5
	Watch     coreThemeIdiom = 6
	Marketing coreThemeIdiom = 7
)

type renditionAttribute struct {
	Name  uint16
	Value uint16
}
type renditionKeyToken struct {
	CursorHotSpot struct {
		X uint16
		Y uint16
	}
	NumberOfAttributes uint16
	Attributes         []renditionAttribute
}

func (k *renditionKeyToken) UnmarshalBinary(data []byte) error {
	r := bytes.NewReader(data)
	if err := binary.Read(r, binary.LittleEndian, &k.CursorHotSpot); err != nil {
		return fmt.Errorf("failed to read rendition key token cursor hotspot: %v", err)
	}
	if err := binary.Read(r, binary.LittleEndian, &k.NumberOfAttributes); err != nil {
		return fmt.Errorf("failed to read rendition key token number of attributes: %v", err)
	}
	k.Attributes = make([]renditionAttribute, k.NumberOfAttributes)
	for i := range k.Attributes {
		if err := binary.Read(r, binary.LittleEndian, &k.Attributes[i]); err != nil {
			return fmt.Errorf("failed to read rendition key token attribute %d: %v", i, err)
		}
	}
	if r.Len() > 0 {
		return fmt.Errorf("failed to read entire rendition key token: %v", r.Len())
	}
	return nil
}

type Rendition struct {
	RenditionName string
	Type          string
	Colorspace    string
	Size          int
	Attributes    map[string]uint16
	Resources     []csiResource
	Asset         any
}

func (r Rendition) ID() uint16 {
	if id, ok := r.Attributes[Identifier.String()]; ok {
		return id
	}
	return 0
}
func (r Rendition) Part() uint16 {
	if id, ok := r.Attributes[Part.String()]; ok {
		return id
	}
	return 0
}
func (r Rendition) Element() uint16 {
	if id, ok := r.Attributes[Element.String()]; ok {
		return id
	}
	return 0
}

func Parse(name string, conf *Config) (*Asset, error) {
	f, err := os.Open(name)
	if err != nil {
		return nil, fmt.Errorf("failed to open file %s: %v", name, err)
	}
	defer f.Close()

	fi, err := os.Stat(name)
	if err != nil {
		return nil, fmt.Errorf("failed to stat file %s: %v", name, err)
	}
	modeTime := fi.ModTime().Local().Unix()

	bm, err := bom.New(f)
	if err != nil {
		return nil, fmt.Errorf("failed to parse BOM file: %v", err)
	}

	a := Asset{conf: conf}

	a.AppearanceDB = make(map[string]uint16)
	a.BitmapKeyDB = make(map[any][]byte)
	a.ColorDB = make(map[string]color.RGBA)
	a.Localizations = make(map[string]uint32)

	if a.conf.Verbose {
		log.WithField("name", name).Debug("Parsing BOM")
		utils.Indent(log.Debug, 2)("Blocks/Trees: " + strings.Join(bm.BlockNames(), ", "))
	}

	saved := make(map[string]int)
	// helpers for unique naming and saving outputs
	uniqName := func(base, ext string) string {
		name := base
		if _, ok := saved[name]; ok {
			saved[name] += 1
			name += fmt.Sprintf("_%d", saved[name])
		} else {
			saved[name] = 0
		}
		if len(ext) > 0 && !strings.HasSuffix(strings.ToLower(name), strings.ToLower(ext)) {
			name += ext
		}
		return name
	}
	saveBytes := func(base, ext string, data []byte) error {
		if a.conf == nil || !a.conf.Export || len(a.conf.Output) == 0 {
			return nil
		}
		fname := uniqName(base, ext)
		return os.WriteFile(filepath.Join(a.conf.Output, fname), data, 0o644)
	}
	savePNG := func(base string, img image.Image) error {
		if a.conf == nil || !a.conf.Export || len(a.conf.Output) == 0 {
			return nil
		}
		fname := uniqName(base, ".png")
		f, err := os.Create(filepath.Join(a.conf.Output, fname))
		if err != nil {
			return err
		}
		defer f.Close()
		return png.Encode(f, img)
	}

	for _, v := range bm.Vars {
		switch v.Name {
		/**********
		 * BLOCKS *
		 **********/
		case "CARHEADER":
			br, err := bm.ReadBlock(v.Name)
			if err != nil {
				return nil, fmt.Errorf("failed to read block %s: %v", v.Name, err)
			}
			if err := binary.Read(br, binary.LittleEndian, &a.Header); err != nil {
				return nil, fmt.Errorf("failed to read CAR header: %v", err)
			}
			if a.Tag != [4]byte{'R', 'A', 'T', 'C'} { // 'CTAR'
				return nil, fmt.Errorf("invalid CAR header tag: %s", a.Tag)
			}
			if a.StorageTimestamp == 0 {
				a.StorageTimestamp = uint32(modeTime) // use file modification time
			}
			// TODO: read tree ? (I see a 'tree' following this data, but that might be some other object's sub-tree)
		case "EXTENDED_METADATA":
			br, err := bm.ReadBlock(v.Name)
			if err != nil {
				return nil, fmt.Errorf("failed to read block %s: %v", v.Name, err)
			}
			if err := binary.Read(br, binary.BigEndian, &a.Metadata); err != nil {
				return nil, fmt.Errorf("failed to read extended metadata: %v", err)
			}
			if a.Metadata.Tag != [4]byte{'M', 'E', 'T', 'A'} {
				return nil, fmt.Errorf("invalid extended metadata tag: %s", a.Metadata.Tag)
			}
		case "KEYFORMAT":
			if err := a.parseKeyFormat(bm); err != nil {
				return nil, fmt.Errorf("failed to parse KEYFORMAT block: %v", err)
			}
		case "CARGLOBALS":
			br, err := bm.ReadBlock(v.Name)
			if err != nil {
				return nil, fmt.Errorf("failed to read block %s: %v", v.Name, err)
			}
			a.Globals, err = io.ReadAll(br)
			if err != nil {
				return nil, fmt.Errorf("failed to read CARGLOBALS data: %v", err)
			}
		case "KEYFORMATWORKAROUND":
			if err := a.parseKeyFormatWorkaround(bm); err != nil {
				return nil, fmt.Errorf("failed to parse KEYFORMATWORKAROUND block: %v", err)
			}
			if a.conf.Verbose {
				br, err := bm.ReadBlock(v.Name)
				if err != nil {
					log.Debugf("Failed to read KEYFORMATWORKAROUND block: %v", err)
				} else {
					data, err := io.ReadAll(br)
					if err != nil {
						log.Debugf("Failed to read KEYFORMATWORKAROUND data: %v", err)
					} else {
						log.Debugf("KEYFORMATWORKAROUND block found (%d bytes)", len(data))
						if len(data) <= 256 {
							log.Debugf("KEYFORMATWORKAROUND hex dump:\n%s", hex.Dump(data))
						}
					}
				}
			}
		case "EXTERNAL_KEYS":
			log.Error("BOM block EXTERNAL_KEYS parsing not implemented yet - please open an issue on github.com/blacktop/ipsw/issues")
		/*********
		 * TREES *
		 *********/
		case "APPEARANCEKEYS":
			tree, err := bm.ReadTree("APPEARANCEKEYS")
			if err != nil {
				return nil, fmt.Errorf("failed to read APPEARANCEKEYS tree: %v", err)
			}
			for _, item := range tree.Indices {
				key, err := io.ReadAll(item.KeyReader)
				if err != nil {
					return nil, fmt.Errorf("failed to read key for APPEARANCEKEYS: %v", err)
				}
				var value uint16
				if err := binary.Read(item.ValueReader, binary.LittleEndian, &value); err != nil {
					return nil, fmt.Errorf("failed to read value for key %s: %v", string(key), err)
				}
				a.AppearanceDB[string(key)] = value
			}
		case "BEZELS":
			log.Error("BOM tree BEZELS not implemented yet - please open an issue on github.com/blacktop/ipsw/issues")
		case "BITMAPKEYS":
			// NOTE: /System/Library/PrivateFrameworks/ChatKit.framework/Assets.car is SUPER weird (keys are many different types)
			tree, err := bm.ReadTree("BITMAPKEYS")
			if err != nil {
				return nil, fmt.Errorf("failed to read BITMAPKEYS tree: %v", err)
			}
			for _, item := range tree.Indices {
				if a.conf.Verbose {
					if err := dumpTreeIndice("BITMAPKEYS", item); err != nil {
						return nil, fmt.Errorf("failed to dump BITMAPKEYS tree indice: %v", err)
					}
				} else {
					value, err := io.ReadAll(item.ValueReader)
					if err != nil {
						return nil, fmt.Errorf("failed to read BITMAPKEYS value: %v", err)
					}
					// TODO: I think if I understand the struct of the value data it might tell me what the key TYPE is
					keyData, err := io.ReadAll(item.KeyReader)
					if err != nil {
						return nil, fmt.Errorf("failed to read BITMAPKEYS key data: %v", err)
					}
					switch {
					case len(keyData) == 0:
						a.BitmapKeyDB[nil] = value
					case len(keyData) == 4:
						var key uint32
						if err := binary.Read(bytes.NewReader(keyData), binary.LittleEndian, &key); err != nil {
							return nil, fmt.Errorf("failed to read BITMAPKEYS key: %v", err)
						}
						a.BitmapKeyDB[key] = value
					case len(keyData) > 4:
						// a.BitmapKeyDB[keyData] = value FIXME: this is an array of bytes (what does it represent?)
					}
				}
			}
		case "COLORS":
			ctrees, err := bm.ReadTrees("COLORS")
			if err != nil {
				return nil, fmt.Errorf("failed to read COLORS tree: %v", err)
			}
			for _, tree := range ctrees {
				for _, item := range tree.Indices {
					var key uint32 // always 0
					if err := binary.Read(item.KeyReader, binary.LittleEndian, &key); err != nil {
						return nil, fmt.Errorf("failed to read COLORS key: %v", err)
					}
					name, err := readString(item.KeyReader)
					if err != nil {
						return nil, fmt.Errorf("failed to read COLORS name: %v", err)
					}
					var sc systemColor
					if err := binary.Read(item.ValueReader, binary.LittleEndian, &sc); err != nil {
						return nil, fmt.Errorf("failed to read COLORS system color: %v", err)
					}
					a.ColorDB[name] = color.RGBA{
						R: sc.Color.Red,
						G: sc.Color.Green,
						B: sc.Color.Blue,
						A: sc.Color.Alpha,
					}
				}
			}
		case "ELEMENT_INFO":
			log.Error("BOM tree ELEMENT_INFO parsing not implemented yet - please open an issue on github.com/blacktop/ipsw/issues")
		case "FACETKEYS":
			if err := a.parseFacetKeys(bm); err != nil {
				return nil, fmt.Errorf("failed to parse FACETKEYS trees: %v", err)
			}
		case "FONTS":
			log.Error("BOM tree FONTS parsing not implemented yet - please open an issue on github.com/blacktop/ipsw/issues")
		case "FONTSIZES":
			log.Error("BOM tree FONTSIZES parsing not implemented yet - please open an issue on github.com/blacktop/ipsw/issues")
		case "GLYPHS":
			log.Error("BOM tree GLYPHS parsing not implemented yet - please open an issue on github.com/blacktop/ipsw/issues")
		case "LOCALIZATIONKEYS":
			tree, err := bm.ReadTree("LOCALIZATIONKEYS")
			if err != nil {
				return nil, fmt.Errorf("failed to read LOCALIZATIONKEYS tree: %v", err)
			}
			for _, item := range tree.Indices {
				key, err := io.ReadAll(item.KeyReader)
				if err != nil {
					return nil, fmt.Errorf("failed to read LOCALIZATIONKEYS key: %v", err)
				}
				valueData, err := io.ReadAll(item.ValueReader)
				if err != nil {
					return nil, fmt.Errorf("failed to read LOCALIZATIONKEYS value data: %v", err)
				}
				var value uint32
				switch len(valueData) {
				case 2:
					value = uint32(binary.LittleEndian.Uint16(valueData))
				case 4:
					value = binary.LittleEndian.Uint32(valueData)
				default:
					return nil, fmt.Errorf("failed to read LOCALIZATIONKEYS value: %v; data=\n%s", err, hex.Dump(valueData))
				}
				a.Localizations[string(key)] = uint32(value)
			}
		case "PART_INFO":
			log.Error("BOM tree PART_INFO parsing not implemented yet - please open an issue on github.com/blacktop/ipsw/issues")
		case "RENDITIONS":
			if err := a.parseKeyFormat(bm); err != nil {
				return nil, fmt.Errorf("failed to parse asset KeyFormat %v", err)
			}
			rtrees, err := bm.ReadTrees("RENDITIONS")
			if err != nil {
				return nil, fmt.Errorf("failed to read 'RENDITIONS' trees: %v", err)
			}
			for _, tree := range rtrees {
				for _, item := range tree.Indices {
					rend := Rendition{
						Attributes: make(map[string]uint16),
					}
					// parse key data
					keyData, err := io.ReadAll(item.KeyReader)
					if err != nil {
						return nil, fmt.Errorf("failed to read 'RENDITIONS' key data: %v", err)
					}
					attrs := make([]uint16, len(keyData)/binary.Size(uint16(0)))
					if err := binary.Read(bytes.NewReader(keyData), binary.LittleEndian, &attrs); err != nil {
						return nil, fmt.Errorf("failed to read 'RENDITIONS' key attributes: %v", err)
					}
					for idx, k := range a.KeyFormat {
						rend.Attributes[k.String()] = attrs[idx]
					}
					// TODO: this might be wasteful if we don't need to read the whole thing
					// parse value data
					vdata, err := io.ReadAll(item.ValueReader)
					if err != nil {
						return nil, fmt.Errorf("failed to read 'RENDITIONS' value data: %v", err)
					}
					vr := bytes.NewReader(vdata)
					cheader, err := readCSIFileHeader(vr)
					if err != nil {
						return nil, fmt.Errorf("failed to read 'RENDITIONS' csiHeader: %v", err)
					}
					resourceData := make([]byte, cheader.ChainSize)
					if _, err := vr.Read(resourceData); err != nil {
						return nil, fmt.Errorf("failed to read 'RENDITIONS' resource data: %v", err)
					}
					rr := bytes.NewReader(resourceData)
					for rr.Len() > 0 {
						var rsc csiResource
						if err := binary.Read(rr, binary.LittleEndian, &rsc.ID); err != nil {
							return nil, fmt.Errorf("failed to read 'RENDITIONS' resource ID: %v", err)
						}
						if err := binary.Read(rr, binary.LittleEndian, &rsc.Length); err != nil {
							return nil, fmt.Errorf("failed to read 'RENDITIONS' resource length: %v", err)
						}
						rsc.Data = make([]byte, rsc.Length)
						if _, err := rr.Read(rsc.Data); err != nil {
							return nil, fmt.Errorf("failed to read 'RENDITIONS' resource data: %v", err)
						}
						rend.Resources = append(rend.Resources, rsc)
					}

					if rendName, _, ok := bytes.Cut(cheader.Metadata.Name[:], []byte{0}); ok {
						rend.RenditionName = string(rendName)
					} else {
						rend.RenditionName = string(bytes.TrimRight(cheader.Metadata.Name[:], "\x00"))
					}
					if len(rend.RenditionName) == 0 {
						rend.RenditionName = "CoreStructuredImage"
					}
					rend.Type = cheader.Metadata.Layout.String()
					rend.Size = int(cheader.ImageIndex.AccumLength[len(cheader.ImageIndex.AccumLength)-1])

					if vr.Len() > 0 {
						pixelFormat := string(utils.ReverseBytes(cheader.PixelFormat[:]))
						// log.WithFields(log.Fields{
						// 	"rendition":   rend.RenditionName,
						// 	"pixelFormat": pixelFormat,
						// }).Info("RENDITION pixel format")
						switch pixelFormat {
						case PixFmtARGB, PixFmtARGB16, PixFmtRGB555, PixFmtGray, PixFmtGray16:
							rend.Type = fmt.Sprintf("Image (%s)", cheader.Metadata.Layout.String())
							if a.conf.Verbose {
								log.WithFields(log.Fields{
									"rendition": rend.RenditionName,
									"layout":    cheader.Metadata.Layout,
								}).Debug("IMAGE layout")
							}
							switch cheader.Metadata.Layout {
							case PackedImage:
								// 	// PackedImage has a special structure - the image data is embedded differently
								// 	// For now, log that it's a packed image and skip decoding
								// 	log.Debugf("PackedImage layout for %s - special handling needed", rend.RenditionName)
								// 	// Store the raw data as the asset
								// 	data, err := io.ReadAll(vr)
								// 	if err != nil {
								// 		return nil, fmt.Errorf("failed to read PackedImage data: %v", err)
								// 	}
								// 	er := bytes.NewReader(data)
								// 	var elem csiElement
								// 	if err := binary.Read(er, binary.LittleEndian, &elem); err != nil {
								// 		return nil, fmt.Errorf("failed to read PackedImage element: %v", err)
								// 	}
								// 	if elem.Signature != [4]byte{'M', 'L', 'E', 'C'} { // 'MLEC'
								// 		return nil, fmt.Errorf("invalid PackedImage signature: %s", elem.Signature)
								// 	}
								// 	edata := make([]byte, elem.Length)
								// 	if _, err := io.ReadFull(er, edata); err != nil {
								// 		return nil, fmt.Errorf("failed to read LZFSE PackedImage data: %v", err)
								// 	}
								// 	switch elem.Encoding {
								// 	case RLE:
								// 		rend.Asset = decodeRLE(edata)
								// 	case LZFSE:
								// 		decompressedData, err := comp.Decompress(edata, comp.LZFSE)
								// 		if err != nil {
								// 			return nil, fmt.Errorf("failed to decompress LZFSE PackedImage data: %v", err)
								// 		}
								// 		rend.Asset = decompressedData
								// 	default:
								// 		log.WithField("encoding", elem.Encoding).Warnf("Unsupported PackedImage encoding for %s", rend.RenditionName)
								// 		rend.Asset = edata
								// 	}
								// TODO: handle other layout special cases
								log.WithField("layout", cheader.Metadata.Layout).Debugf("Unsupported PackedImage layout for %s", rend.RenditionName)
								fallthrough
							default:
								// Extract optional ImageRowBytes from resources for correct stride
								var rowBytes uint32
								for _, rsc := range rend.Resources {
									if rsc.ID == ImageRowBytesID && len(rsc.Data) >= 4 {
										_ = binary.Read(bytes.NewReader(rsc.Data), binary.LittleEndian, &rowBytes)
										break
									}
								}
								img, err := decodeImage(vr, *cheader, conf, int(rowBytes))
								if err != nil {
									if a.conf.Verbose {
										log.Errorf("failed to decode image '%s': %v; data:\n%s", rend.RenditionName, err, hex.Dump(vdata))
									} else {
										log.Errorf("failed to decode image '%s': %v", rend.RenditionName, err)
									}
									// return nil, err
								}
								if img != nil && err == nil {
									if err := savePNG(rend.RenditionName, img); err != nil {
										return nil, err
									}
									if a.conf.Verbose {
										// display image in terminal
										log.Debug(rend.RenditionName)
										var dat bytes.Buffer
										buf := bufio.NewWriter(&dat)
										if err := png.Encode(buf, img); err != nil {
											return nil, err
										}
										buf.Flush()
										ti, err := termimg.From(bytes.NewReader(dat.Bytes()))
										if err != nil {
											return nil, fmt.Errorf("failed to create termimg from image: %v", err)
										}
										if err := ti.Print(); err != nil {
											return nil, fmt.Errorf("failed to print termimg: %v", err)
										}
									}
									rend.Asset = img
								}
							}
						case PixFmtPDF:
							rend.Type = "PDF"
							// Read PDF data
							pdfData, err := io.ReadAll(vr)
							if err != nil {
								log.Errorf("failed to read PDF data: %v", err)
							} else {
								// Store raw PDF data as asset
								rend.Asset = pdfData
								if err := saveBytes(rend.RenditionName, ".pdf", pdfData); err != nil {
									return nil, err
								}
							}
						case PixFmtJPEG:
							rend.Type = "JPEG"
							// Read JPEG data
							jpegData, err := io.ReadAll(vr)
							if err != nil {
								log.Errorf("failed to read JPEG data: %v", err)
							} else {
								// Store raw JPEG data as asset
								rend.Asset = jpegData
								if err := saveBytes(rend.RenditionName, ".jpg", jpegData); err != nil {
									return nil, err
								}
							}
						case PixFmtHEIF:
							rend.Type = "HEIF"
							// Read HEIF data
							heifData, err := io.ReadAll(vr)
							if err != nil {
								log.Errorf("failed to read HEIF data: %v", err)
							} else {
								// Store raw HEIF data as asset
								rend.Asset = heifData
								if err := saveBytes(rend.RenditionName, ".heic", heifData); err != nil {
									return nil, err
								}
							}
						case PixFmtRawData:
							rend.Type = "Data"
							var rawd csiRawData
							if err := binary.Read(vr, binary.LittleEndian, &rawd.Signature); err != nil {
								return nil, fmt.Errorf("failed to read rendition raw data signature: %v", err)
							}
							if rawd.Signature != [4]byte{'D', 'W', 'A', 'R'} { // 'RAWD'
								return nil, fmt.Errorf("invalid rendition raw data signature: %s", rawd.Signature)
							}
							if err := binary.Read(vr, binary.LittleEndian, &rawd.Flags); err != nil {
								return nil, fmt.Errorf("failed to read rendition raw data flags: %v", err)
							}
							if err := binary.Read(vr, binary.LittleEndian, &rawd.Length); err != nil {
								return nil, fmt.Errorf("failed to read rendition raw data length: %v", err)
							}
							if rawd.Length != uint32(vr.Len()) {
								return nil, fmt.Errorf("rendition raw data length mismatch: expected %d, got %d", rawd.Length, vr.Len())
							}
							if rawd.Length > 0 {
								if a.conf != nil && a.conf.Export && len(a.conf.Output) > 0 {
									data := make([]byte, rawd.Length)
									if _, err := vr.Read(data); err != nil {
										return nil, fmt.Errorf("failed to read rendition raw data: %v", err)
									}
									fname := a.GetName(rend.ID())
									if len(fname) == 0 {
										fname = rend.RenditionName + ".raw"
									}
									if err := os.WriteFile(filepath.Join(a.conf.Output, fname), data, 0644); err != nil {
										return nil, err
									}
								}
							}
						case "\x00\x00\x00\x00":
							// log.WithFields(log.Fields{
							// 	"name":   rend.RenditionName,
							// 	"name2":  string(bytes.Trim(cheader.Metadata.Name[:], "\x00")),
							// 	"layout": cheader.Metadata.Layout,
							// }).Info("RENDITION layout")
							switch cheader.Metadata.Layout {
							case OnePart, ThreePartHorizontal, ThreePartVertical, NinePart, TwelvePart, ManyPart:
								fallthrough
							case Gradient:
								fallthrough
							case Effect:
								fallthrough
							case Animation:
								fallthrough
							case Vector:
								fallthrough
							case IconImage:
								fallthrough
							case RawData:
								fallthrough
							case ExternalLink:
								fallthrough
							case ImageStack:
								log.Errorf("RENDITION layout %s not supported yet - please open an issue on github.com/blacktop/ipsw/issues", cheader.Metadata.Layout)
							case InternalLink:
								var ilink csiInternalLinkData
								if err := ilink.UnmarshalBinary(vr); err != nil {
									return nil, fmt.Errorf("failed to parse rendition internal link: %v", err)
								}
								rend.Asset = ilink
							case PackedImage:
								fallthrough
							case NamedContents:
								fallthrough
							case ThinningPlaceholder:
								fallthrough
							case TextureRendition:
								fallthrough
							case TextureImage:
								log.Errorf("RENDITION layout %s not supported yet - please open an issue on github.com/blacktop/ipsw/issues", cheader.Metadata.Layout)
							case Color:
								var c csiColor
								if err := binary.Read(vr, binary.LittleEndian, &c.Signature); err != nil {
									return nil, fmt.Errorf("failed to read rendition color signature: %v", err)
								}
								if err := binary.Read(vr, binary.LittleEndian, &c.Version); err != nil {
									return nil, fmt.Errorf("failed to read rendition color version: %v", err)
								}
								if err := binary.Read(vr, binary.LittleEndian, &c.Info); err != nil {
									return nil, fmt.Errorf("failed to read rendition color info: %v", err)
								}
								if err := binary.Read(vr, binary.LittleEndian, &c.NumberOfComponents); err != nil {
									return nil, fmt.Errorf("failed to read rendition color number of components: %v", err)
								}
								c.Components = make([]float64, c.NumberOfComponents)
								if err := binary.Read(vr, binary.LittleEndian, &c.Components); err != nil {
									return nil, fmt.Errorf("failed to read rendition color components: %v", err)
								}
								if c.Info.ColorType() == SystemColorFollows {
									var sysc csiSystemColorName
									if err := binary.Read(vr, binary.LittleEndian, &sysc.Signature); err != nil {
										return nil, fmt.Errorf("failed to read rendition system color signature: %v", err)
									}
									if err := binary.Read(vr, binary.LittleEndian, &sysc.Version); err != nil {
										return nil, fmt.Errorf("failed to read rendition system color version: %v", err)
									}
									if err := binary.Read(vr, binary.LittleEndian, &sysc.Length); err != nil {
										return nil, fmt.Errorf("failed to read rendition system color name length: %v", err)
									}
									sysc.Name = make([]byte, sysc.Length)
									if _, err := vr.Read(sysc.Name); err != nil {
										return nil, fmt.Errorf("failed to read rendition system color name: %v", err)
									}
									rend.Asset = sysc // FIXME: this will stomp the outer color?
								}
								rend.Asset = c
							case MultiSizeImageSet:
								var msi csiMultisizeImageSet
								if err := binary.Read(vr, binary.LittleEndian, &msi.Signature); err != nil {
									return nil, err
								}
								if err := binary.Read(vr, binary.LittleEndian, &msi.Version); err != nil {
									return nil, err
								}
								if err := binary.Read(vr, binary.LittleEndian, &msi.NImageSizes); err != nil {
									return nil, err
								}
								msi.ImageSizes = make([]csiMultiImgSetImageSize, msi.NImageSizes)
								if err := binary.Read(vr, binary.LittleEndian, &msi.ImageSizes); err != nil {
									return nil, err
								}
								rend.Asset = msi
							case ModelIOAsset:
								fallthrough
							case ModelMesh:
								fallthrough
							case RecognitionGroup:
								fallthrough
							case RecognitionObject:
								fallthrough
							case ModelIOSubmesh:
								fallthrough
							case VectorGlyph:
								fallthrough
							case SolidImageStack:
								fallthrough
							case IconImageStack:
								fallthrough
							case IconGroup:
								log.Errorf("RENDITION layout %s not supported yet - please open an issue on github.com/blacktop/ipsw/issues", cheader.Metadata.Layout)
							case NamedGradient:
								var ng csiNamedGradient
								if err := binary.Read(vr, binary.LittleEndian, &ng.Signature); err != nil {
									return nil, fmt.Errorf("failed to read rendition named gradient signature: %v", err)
								}
								if err := binary.Read(vr, binary.LittleEndian, &ng.ColorCount); err != nil {
									return nil, fmt.Errorf("failed to read rendition named gradient color count: %v", err)
								}
								if err := binary.Read(vr, binary.LittleEndian, &ng.Type); err != nil {
									return nil, fmt.Errorf("failed to read rendition named gradient type: %v", err)
								}
								ng.StartStops = make([]gradientStartStops, ng.ColorCount)
								if err := binary.Read(vr, binary.LittleEndian, &ng.StartStops); err != nil {
									return nil, fmt.Errorf("failed to read rendition named gradient starts: %v", err)
								}
								ng.Stops = make([]gradientStop, ng.ColorCount)
								for i := range ng.Stops {
									if err := binary.Read(vr, binary.LittleEndian, &ng.Stops[i].Stop); err != nil {
										return nil, fmt.Errorf("failed to read rendition named gradient stop color: %v", err)
									}
									if err := binary.Read(vr, binary.LittleEndian, &ng.Stops[i].NameLength); err != nil {
										return nil, fmt.Errorf("failed to read rendition named gradient stop name length: %v", err)
									}
									ng.Stops[i].Name = make([]byte, ng.Stops[i].NameLength)
									if _, err := vr.Read(ng.Stops[i].Name); err != nil {
										return nil, fmt.Errorf("failed to read rendition named gradient stop name: %v", err)
									}
								}
								rend.Asset = ng
							default:
								return nil, fmt.Errorf("unknown RENDITION layout: %d - please open an issue on github.com/blacktop/ipsw/issues", cheader.Metadata.Layout)
							}
						default:
							log.Errorf("unknown pixel format: %s", pixelFormat)
						}
					}
					a.ImageDB = append(a.ImageDB, rend)
				}
			}
		default:
			return nil, fmt.Errorf("unknown BOM block/tree: '%s' - please open an issue on github.com/blacktop/ipsw/issues", name)
		}
	}

	return &a, nil
}

func (a *Asset) parseFacetKeys(bm *bom.BOM) error {
	if a.FacetKeyDB != nil {
		return nil
	}

	a.FacetKeyDB = make(map[string]renditionKeyToken)

	ftree, err := bm.ReadTrees("FACETKEYS")
	if err != nil {
		return fmt.Errorf("failed to read 'FACETKEYS' tree: %v", err)
	}

	for _, tree := range ftree {
		for _, item := range tree.Indices {
			var token renditionKeyToken
			if err := binary.Read(item.ValueReader, binary.LittleEndian, &token.CursorHotSpot); err != nil {
				return fmt.Errorf("failed to read 'FACETKEYS' cursor hotspot: %v", err)
			}
			if err := binary.Read(item.ValueReader, binary.LittleEndian, &token.NumberOfAttributes); err != nil {
				return fmt.Errorf("failed to read 'FACETKEYS' number of attributes: %v", err)
			}
			token.Attributes = make([]renditionAttribute, token.NumberOfAttributes)
			if err := binary.Read(item.ValueReader, binary.LittleEndian, &token.Attributes); err != nil {
				return fmt.Errorf("failed to read 'FACETKEYS' attributes: %v", err)
			}
			name, err := io.ReadAll(item.KeyReader)
			if err != nil {
				return fmt.Errorf("failed to read 'FACETKEYS' name: %v", err)
			}
			a.FacetKeyDB[string(name)] = token
		}
	}

	return nil
}

func (a *Asset) parseKeyFormat(bm *bom.BOM) error {
	if a.KeyFormat != nil {
		return nil
	}
	br, err := bm.ReadBlock("KEYFORMAT")
	if err != nil {
		if workaroundErr := a.parseKeyFormatWorkaround(bm); workaroundErr != nil {
			return fmt.Errorf("failed to read block 'KEYFORMAT': %v; fallback 'KEYFORMATWORKAROUND' parse failed: %v", err, workaroundErr)
		}
		return nil
	}
	var keyfmt RenditionKeyformat
	if err := binary.Read(br, binary.LittleEndian, &keyfmt.Tag); err != nil {
		return fmt.Errorf("failed to read 'KEYFORMAT' tag: %v", err)
	}
	if keyfmt.Tag != [4]byte{'t', 'm', 'f', 'k'} { // 'kfmt'
		return fmt.Errorf("invalid 'KEYFORMAT' tag: %s", keyfmt.Tag)
	}
	if err := binary.Read(br, binary.LittleEndian, &keyfmt.Version); err != nil {
		return fmt.Errorf("failed to read 'KEYFORMAT' version: %v", err)
	}
	if err := binary.Read(br, binary.LittleEndian, &keyfmt.MaximumRenditionKeyTokenCount); err != nil {
		return fmt.Errorf("failed to read 'KEYFORMAT' maximum rendition key token count: %v", err)
	}
	a.KeyFormat = make([]renditionAttributeType, keyfmt.MaximumRenditionKeyTokenCount)
	if err := binary.Read(br, binary.LittleEndian, &a.KeyFormat); err != nil {
		return fmt.Errorf("failed to read 'KEYFORMAT' rendition attribute types: %v", err)
	}
	return nil
}

func (a *Asset) parseKeyFormatWorkaround(bm *bom.BOM) error {
	if a.KeyFormat != nil {
		return nil
	}
	br, err := bm.ReadBlock("KEYFORMATWORKAROUND")
	if err != nil {
		return fmt.Errorf("failed to read block 'KEYFORMATWORKAROUND': %v", err)
	}

	var maxTokenCount uint32
	if err := binary.Read(br, binary.LittleEndian, &maxTokenCount); err != nil {
		return fmt.Errorf("failed to read KEYFORMATWORKAROUND max token count: %v", err)
	}
	if maxTokenCount == 0 {
		return nil
	}

	a.KeyFormat = make([]renditionAttributeType, maxTokenCount)
	if err := binary.Read(br, binary.LittleEndian, &a.KeyFormat); err != nil {
		return fmt.Errorf("failed to read KEYFORMATWORKAROUND rendition attribute types: %v", err)
	}
	return nil
}

// TODO: this is gross
func readCSIFileHeader(r io.Reader) (*csiHeader, error) {
	var c csiHeader
	if err := binary.Read(r, binary.BigEndian, &c.Signature); err != nil {
		return nil, fmt.Errorf("failed to read csiHeader signature: %v", err)
	}
	if c.Signature != CsiFileSignature {
		return nil, fmt.Errorf("invalid csiHeader signature: %v", c.Signature)
	}
	if err := binary.Read(r, binary.LittleEndian, &c.Version); err != nil {
		return nil, fmt.Errorf("failed to read csiHeader version: %v", err)
	}
	if err := binary.Read(r, binary.LittleEndian, &c.Flags); err != nil {
		return nil, fmt.Errorf("failed to read csiHeader flags: %v", err)
	}
	if err := binary.Read(r, binary.LittleEndian, &c.Width); err != nil {
		return nil, fmt.Errorf("failed to read csiHeader width: %v", err)
	}
	if err := binary.Read(r, binary.LittleEndian, &c.Height); err != nil {
		return nil, fmt.Errorf("failed to read csiHeader height: %v", err)
	}
	if err := binary.Read(r, binary.LittleEndian, &c.ScaleFactor); err != nil {
		return nil, fmt.Errorf("failed to read csiHeader ppi: %v", err)
	}
	if err := binary.Read(r, binary.LittleEndian, &c.PixelFormat); err != nil {
		return nil, fmt.Errorf("failed to read csiHeader pixel format: %v", err)
	}
	if err := binary.Read(r, binary.LittleEndian, &c.ColorSpace); err != nil {
		return nil, fmt.Errorf("failed to read csiHeader color space: %v", err)
	}
	if err := binary.Read(r, binary.LittleEndian, &c.Metadata); err != nil {
		return nil, fmt.Errorf("failed to read csiHeader metadata: %v", err)
	}
	if err := binary.Read(r, binary.LittleEndian, &c.ChainSize); err != nil {
		return nil, fmt.Errorf("failed to read csiHeader chain size: %v", err)
	}
	if err := binary.Read(r, binary.LittleEndian, &c.ImageIndex.Count); err != nil {
		return nil, fmt.Errorf("failed to read csiHeader image index count: %v", err)
	}
	c.ImageIndex.AccumLength = make([]uint32, c.ImageIndex.Count+1)
	if err := binary.Read(r, binary.LittleEndian, &c.ImageIndex.AccumLength); err != nil {
		return nil, fmt.Errorf("failed to read csiHeader image index accum lengths: %v", err)
	}
	return &c, nil
}

// decodeRLE implements a PackBits-like RLE commonly used in CoreUI payloads.
// Control byte N:
//   - 0..127   : copy the next (N+1) literal bytes
//   - 129..255 : repeat the next byte (257 - N) times
//   - 128      : no-op
func decodeRLE(src []byte) []byte {
	var dst []byte
	for i := 0; i < len(src); {
		n := int(int8(src[i]))
		i++
		switch {
		case n >= 0:
			count := n + 1
			if i+count > len(src) {
				count = len(src) - i
			}
			dst = append(dst, src[i:i+count]...)
			i += count
		case n == -128:
			// nop
		default:
			if i >= len(src) {
				break
			}
			b := src[i]
			i++
			count := 1 - n
			for range count {
				dst = append(dst, b)
			}
		}
	}
	return dst
}

func readString(r io.Reader) (string, error) {
	scanner := bufio.NewScanner(r)
	for scanner.Scan() {
		return strings.Trim(scanner.Text(), "\x00"), nil
	}
	return "", scanner.Err()
}

func dumpTreeIndice(block string, item bom.TreeIndex) error {
	keyData, err := io.ReadAll(item.KeyReader)
	if err != nil {
		return fmt.Errorf("failed to read %s key: %v", block, err)
	}
	println(block + " KEY")
	println(hex.Dump(keyData))

	valueData, err := io.ReadAll(item.ValueReader)
	if err != nil {
		return fmt.Errorf("failed to read %s value: %v", block, err)
	}
	println(block + " VALUE")
	println(hex.Dump(valueData))

	return nil
}