Add bambu-nfc dump parse, Key-A HKDF, and spool merge.

Parse filanfc-dump/v1 zip/JSON, Bambu 1K images, and merge stickers by tray UID. dump and mifare packages stay importable for a later common library.

parse.go

@@ -0,0 +1,156 @@
+package bambunfc
+
+import (
+	"bytes"
+	"encoding/binary"
+	"encoding/hex"
+	"fmt"
+	"io"
+	"math"
+	"strings"
+
+	"git.s1d3sw1ped.com/s1d3sw1ped/bambu-nfc/dump"
+	"git.s1d3sw1ped.com/s1d3sw1ped/bambu-nfc/mifare"
+)
+
+const BrandBambuLab = "Bambu Lab"
+
+// requiredSectors must not appear in SectorsFail (blocks 0–2, 4–6, 8–9).
+var requiredSectors = []int{0, 1, 2}
+
+// Tag is one Bambu sticker after parsing the 1K image.
+type Tag struct {
+	Brand         string
+	ChipUID       string
+	TrayUID       string
+	Type          string
+	Material      string
+	MaterialID    string
+	VariantID     string
+	Color         Color
+	WeightG       int
+	DiameterMM    float32
+	LengthM       int
+	MinHotendC    int
+	MaxHotendC    int
+	BedC          int
+	DryC          int
+	DryHours      int
+	Produced      string
+	SpoolWidthRaw uint16
+}
+
+func failedSet(fail []int) map[int]bool {
+	s := make(map[int]bool, len(fail))
+	for _, n := range fail {
+		s[n] = true
+	}
+	return s
+}
+
+func block(image []byte, n int) []byte {
+	off := n * mifare.BlockSize
+	return image[off : off+mifare.BlockSize]
+}
+
+func cstr(b []byte) string {
+	if i := bytes.IndexByte(b, 0); i >= 0 {
+		b = b[:i]
+	}
+	return string(b)
+}
+
+func normalizeUID(uid string) (string, error) {
+	uid = strings.ToLower(strings.TrimSpace(uid))
+	if uid == "" || len(uid)%2 != 0 {
+		return "", fmt.Errorf("%w: %q", ErrUID, uid)
+	}
+	if _, err := hex.DecodeString(uid); err != nil {
+		return "", fmt.Errorf("%w: %v", ErrUID, err)
+	}
+	return uid, nil
+}
+
+// ParseImage parses a Bambu MIFARE Classic 1K image.
+// fail is the dump's sectors_fail list (sector indexes 0–15).
+func ParseImage(chipUID string, image []byte, fail []int) (Tag, error) {
+	var zero Tag
+	uid, err := normalizeUID(chipUID)
+	if err != nil {
+		return zero, err
+	}
+	if len(image) != mifare.Size1K {
+		return zero, fmt.Errorf("%w: want %d got %d", ErrImageSize, mifare.Size1K, len(image))
+	}
+	failed := failedSet(fail)
+	for _, s := range requiredSectors {
+		if failed[s] {
+			return zero, fmt.Errorf("%w: sector %d", ErrIncomplete, s)
+		}
+	}
+
+	b1 := block(image, 1)
+	b2 := block(image, 2)
+	b4 := block(image, 4)
+	b5 := block(image, 5)
+	b6 := block(image, 6)
+	b9 := block(image, 9)
+
+	material := cstr(b2)
+	typ := cstr(b4)
+	if material == "" && typ == "" {
+		return zero, ErrNotBambu
+	}
+
+	tag := Tag{
+		Brand:      BrandBambuLab,
+		ChipUID:    uid,
+		VariantID:  cstr(b1[0:8]),
+		MaterialID: cstr(b1[8:16]),
+		Material:   material,
+		Type:       typ,
+		Color: Color{
+			R: b5[0], G: b5[1], B: b5[2], A: b5[3],
+		},
+		WeightG:    int(binary.LittleEndian.Uint16(b5[4:6])),
+		DiameterMM: math.Float32frombits(binary.LittleEndian.Uint32(b5[8:12])),
+		TrayUID:    hex.EncodeToString(b9),
+		DryC:       int(binary.LittleEndian.Uint16(b6[0:2])),
+		DryHours:   int(binary.LittleEndian.Uint16(b6[2:4])),
+		BedC:       int(binary.LittleEndian.Uint16(b6[6:8])),
+		MaxHotendC: int(binary.LittleEndian.Uint16(b6[8:10])),
+		MinHotendC: int(binary.LittleEndian.Uint16(b6[10:12])),
+	}
+	if !failed[2] {
+		b10 := block(image, 10)
+		tag.SpoolWidthRaw = binary.LittleEndian.Uint16(b10[4:6])
+	}
+	if !failed[3] {
+		tag.Produced = cstr(block(image, 12))
+		b14 := block(image, 14)
+		tag.LengthM = int(binary.LittleEndian.Uint16(b14[4:6]))
+	}
+	return tag, nil
+}
+
+// ParseDump parses one dump JSON record as a Bambu tag.
+func ParseDump(d dump.Dump) (Tag, error) {
+	return ParseImage(d.ChipUID, d.Image, d.SectorsFail)
+}
+
+// ParseZip reads a filanfc-dump zip and parses every sticker as Bambu.
+func ParseZip(r io.Reader) ([]Tag, error) {
+	dumps, err := dump.ParseZip(r)
+	if err != nil {
+		return nil, fmt.Errorf("%w: %v", ErrInvalidDump, err)
+	}
+	tags := make([]Tag, 0, len(dumps))
+	for _, d := range dumps {
+		tag, err := ParseDump(d)
+		if err != nil {
+			return nil, fmt.Errorf("chip %s: %w", d.ChipUID, err)
+		}
+		tags = append(tags, tag)
+	}
+	return tags, nil
+}