start refactor

7 files changed, 155 insertions, 201 deletions

diff --git a/auction.go b/auction.go
index e4f53b7..32e9758 100644
--- a/auction.go
+++ b/auction.go
@@ -6,7 +6,13 @@ import (
 	"crypto/sha512"
 	"encoding/base32"
 	"encoding/json"
+	"errors"
+	"fmt"
+	"log/slog"
 	"time"
+
+	"kesim.org/seal/nizk/commit"
+	"kesim.org/seal/nizk/stage1"
 )
 
 type Type int
@@ -55,4 +61,126 @@ func (d *Description) Hash() (hash string, e error) {
 	}
 	h := sha512.Sum512(buf.Bytes())
 	return base32.StdEncoding.EncodeToString(h[:]), nil
-}
\ No newline at end of file
+}
+
+func (d *Description) validate() error {
+	if d == nil {
+		return fmt.Errorf("description is nil")
+	}
+	if d.BitLength > MAXBITLENGTH {
+		return fmt.Errorf("invalid BitLength in description: %d", d.BitLength)
+	}
+	return nil
+}
+
+type Auction interface {
+	Start() error
+	Cancel() error
+	Message(msg []byte) error
+}
+
+type Result struct {
+	Price  uint32
+	Winner string
+	Error  error
+}
+
+type auction struct {
+	description *Description
+
+	// non nil if run by an bidder, via Join()
+	bidder Bidder
+	// non nil if run by an observer, via Observe()
+	observer Observer
+
+	// The commitments we received from the bidders.
+	bidders map[string][]*commit.Commitment
+
+	// sorted list of the bidders.
+	bidder_ids []string
+
+	// Stage 1 data per round
+	stage1 []*stage1.Statement
+
+	log *slog.Logger
+}
+
+func (a *auction) Start() error {
+	return errors.New("Start not implemented")
+}
+
+func (a *auction) Cancel() error {
+	return errors.New("Cancel not implemented")
+}
+
+// Message is called by the Bidder or Visitor
+// whenever a message came in for the auction via the dashboard
+// or other means of communication.
+func (a *auction) Message(msg []byte) error {
+	return fmt.Errorf("Auction.Received not implemented")
+}
+
+const MAXBITLENGTH = 64
+
+// Bidder is the interface that the Auction engine uses to interact
+type Bidder interface {
+	Broadcast([]byte) error
+	Result(Result)
+	Start()
+}
+
+func Join(
+	bidder Bidder,
+	description *Description,
+	options ...Option) (Auction, error) {
+
+	if bidder == nil {
+		return nil, fmt.Errorf("missing bidder")
+	}
+	if e := description.validate(); e != nil {
+		return nil, e
+	}
+
+	a := &auction{
+		description: description,
+		bidder:      bidder,
+		log:         slog.Default(),
+	}
+
+	for _, opt := range options {
+		opt(a)
+	}
+
+	return a, nil
+}
+
+// Observer
+type Observer interface {
+	Result(Result)
+	Start()
+}
+
+func Observe(
+	observer Observer,
+	description *Description,
+	options ...Option) (Auction, error) {
+
+	if observer == nil {
+		return nil, fmt.Errorf("missing observer")
+	}
+	if e := description.validate(); e != nil {
+		return nil, e
+	}
+
+	a := &auction{
+		description: description,
+		observer:    observer,
+		log:         slog.Default(),
+	}
+
+	for _, opt := range options {
+		opt(a)
+	}
+
+	return a, nil
+}
diff --git a/bidder/auction.go b/bidder/auction.go
deleted file mode 100644
index a22f005..0000000
--- a/bidder/auction.go
+++ /dev/null
@@ -1,67 +0,0 @@
-package bidder
-
-import (
-	"fmt"
-	"log"
-	"os"
-
-	"kesim.org/seal"
-	"kesim.org/seal/nizk/commit"
-)
-
-// Auction is the simple interface for the engine
-type Auction interface {
-	Join(bidder Bidder)                   // A bidder calls this to join the auction
-	GotMessage(msg []byte, sig []byte) error // A bidder uses this method to publish a message
-}
-
-// Bidder is the interface that the Auction engine uses to communicate
-type Bidder interface {
-	Commitment() *commit.Commitment
-	Start(map[string]*commit.Commitment)
-	Result()
-	Receive(msg []byte) error
-}
-
-type auction struct {
-	description *seal.Description
-
-	bidder Bidder
-
-	log     func(string, ...any)
-	verbose func(string, ...any)
-	debug   func(string, ...any)
-}
-
-func nullf(string, ...any) {}
-
-func NewAuction(description *seal.Description, options ...Option) (a *auction, e error) {
-	if description.BitLength > 63 {
-		return nil, fmt.Errorf("Invalid BitLength in description: %d", description.BitLength)
-	}
-
-	logger := log.New(os.Stdout, "[seal::client] ", log.LstdFlags)
-
-	a = &auction{
-		description: description,
-		log:         logger.Printf,
-		verbose:     nullf,
-		debug:       nullf,
-	}
-
-	for _, opt := range options {
-		opt(a)
-	}
-
-	return a, nil
-}
-
-func (a *auction) Join(bidder Bidder) {
-	a.bidder = bidder
-}
-
-// Received is called by the bidder whenever a message came in for the auction via the dashboard
-// or other means of communication.
-func (a *auction) Received(msg []byte) error {
-	return fmt.Errorf("Auction.Received not implemented")
-}
\ No newline at end of file
diff --git a/bidder/bid.go b/bidder/bid.go
deleted file mode 100644
index 5f98a0c..0000000
--- a/bidder/bid.go
+++ /dev/null
@@ -1,77 +0,0 @@
-package bidder
-
-import (
-	"crypto/ed25519"
-	"fmt"
-
-	. "kesim.org/seal/nizk"
-
-	"kesim.org/seal/nizk/commit"
-	"kesim.org/seal/nizk/stage1"
-)
-
-type bid struct {
-	id ed25519.PrivateKey
-	Id ed25519.PublicKey
-
-	price     uint64 // bigendian encoding of the bid
-	bitlength uint8  // number of bits encoded in price.
-
-	// bits are derived from zbid and the zero element in
-	// the slice corresponds to the highest bit in zbid
-	bits []*commit.Statement
-
-	// The commitments we received from the bidders.
-	bidders map[string][]*commit.Commitment
-
-	// sorted list of the bidders.
-	bidder_ids []string
-
-	// Stage 1 data per round
-	stage1 []*stage1.Statement
-}
-
-// newBid creates a new Bidder for the given price, using the lower bits up to bitlength
-func newBid(price uint64, bitlength uint8) (b *bid, e error) {
-	if bitlength > 63 {
-		return nil, fmt.Errorf("bitlength too large, maximum is 63")
-	} else if 0 != (price >> bitlength) {
-		return nil, fmt.Errorf("price %d too large for given bitlength %d", price, bitlength)
-	}
-
-	b = &bid{
-		price:     price,
-		bitlength: bitlength,
-	}
-
-	b.Id, b.id, e = ed25519.GenerateKey(nil)
-	if e != nil {
-		return nil, e
-	}
-
-	b.bits = make([]*commit.Statement, bitlength)
-	for i := bitlength; i > 0; i-- {
-		set := (price>>(i-1)&1 != 0)
-		x, r := Curve.RandomScalar(), Curve.RandomScalar()
-		b.bits[i-1] = commit.NewStatement(x, r, set)
-	}
-
-	return b, nil
-}
-
-// Commit returns the public commitment to the bits and a signature
-// TODO: return signature over bid
-func (bid *bid) Commit() (c []*commit.Commitment) {
-	c = make([]*commit.Commitment, len(bid.bits))
-	for i := range bid.bits {
-		c[i] = bid.bits[i].Commit(Bites(bid.Id))
-	}
-	return c
-}
-
-func (bid *bid) Result() {
-}
-
-func (bid *bid) Send(msg []byte, sig []byte) error {
-	return fmt.Errorf("bidder.Send not implemented")
-}
\ No newline at end of file
diff --git a/bidder/bid_test.go b/bidder/bid_test.go
deleted file mode 100644
index a479e5d..0000000
--- a/bidder/bid_test.go
+++ /dev/null
@@ -1,27 +0,0 @@
-package bidder
-
-import (
-	"testing"
-)
-
-func TestBitlengthTooLarge(t *testing.T) {
-	bid, e := newBid(0xFFFFFF, 70)
-	if e == nil {
-		t.Fatalf("failure expected, but got bid: %#v", bid)
-	}
-}
-
-func TestPriceTooLarge(t *testing.T) {
-	bid, e := newBid(0xFFFFFF, 8)
-	if e == nil {
-		t.Fatalf("failure expected, but got bid: %#v", bid)
-	}
-}
-
-func TestBidOK(t *testing.T) {
-	bid, e := newBid(102400, 24)
-	if e != nil {
-		t.Fatalf("unexpected error: %v", e)
-	}
-	t.Logf("Bid: %+v", bid)
-}
\ No newline at end of file
diff --git a/bidder/option.go b/bidder/option.go
deleted file mode 100644
index d1c9783..0000000
--- a/bidder/option.go
+++ /dev/null
@@ -1,18 +0,0 @@
-package bidder
-
-import (
-	"log"
-	"os"
-)
-
-type Option func(auction *auction)
-
-func OptVerbose(a *auction) {
-	logger := log.New(os.Stdout, "[seal::client][verbose] ", log.LstdFlags)
-	a.verbose = logger.Printf
-}
-
-func OptDebug(a *auction) {
-	logger := log.New(os.Stdout, "[seal::client][debug] ", log.LstdFlags)
-	a.debug = logger.Printf
-}
diff --git a/nizk/commit/commit.go b/nizk/commit/commit.go
index d044077..84ba8e5 100644
--- a/nizk/commit/commit.go
+++ b/nizk/commit/commit.go
@@ -12,10 +12,10 @@ import (
 // for given C, A and B
 
 type Statement struct {
+	bitSet bool
 	a    *Scalar
 	b    *Scalar
-	plus bool
-	*Commitment
+	Commitment
 }
 
 type Commitment struct {
@@ -25,25 +25,25 @@ type Commitment struct {
 	Proof *Proof
 }
 
-func NewStatement(a, b *Scalar, plus bool) *Statement {
+func NewStatement(a, b *Scalar, bitSet bool) *Statement {
 	return &Statement{
 		a:          a,
 		b:          b,
-		plus:       plus,
-		Commitment: commitment(a, b, plus),
+		bitSet:       bitSet,
+		Commitment: commitment(a, b, bitSet),
 	}
 }
 
-func commitment(a, b *Scalar, plus bool) *Commitment {
+func commitment(a, b *Scalar, bitSet bool) Commitment {
 	var C *Point
 	c := a.Mul(b)
 
-	if plus {
+	if bitSet {
 		C = G.Exp(c.Add(One))
 	} else {
 		C = G.Exp(c)
 	}
-	return &Commitment{
+	return Commitment{
 		C: C,
 		A: G.Exp(a),
 		B: G.Exp(b),
@@ -52,7 +52,7 @@ func commitment(a, b *Scalar, plus bool) *Commitment {
 
 func (s *Statement) Commit(id Bytes) *Commitment {
 	s.Commitment.Proof = s.Proof(id)
-	return s.Commitment
+	return &s.Commitment
 }
 
 type Proof struct {
@@ -72,7 +72,7 @@ func (s *Statement) Proof(id Bytes) *Proof {
 	r2 = Curve.RandomScalar()
 	w = Curve.RandomScalar()
 
-	if s.plus {
+	if s.bitSet {
 		e[0][0] = G.Exp(r1)
 		e[0][1] = s.B.Exp(r1).Mul(G.Exp(w))
 		e[1][0] = G.Exp(r2)
@@ -87,7 +87,7 @@ func (s *Statement) Proof(id Bytes) *Proof {
 	ch := Challenge(G, s.C, s.A, s.B, e[0][0], e[0][1], e[1][0], e[1][1], id)
 	pr := &Proof{Id: id}
 
-	if s.plus {
+	if s.bitSet {
 		pr.C.Ch[0] = w
 		pr.C.Ch[1] = ch.Sub(w)
 		pr.C.R[0] = r1.Sub(s.a.Mul(pr.C.Ch[0]))
diff --git a/option.go b/option.go
new file mode 100644
index 0000000..8f7212f
--- /dev/null
+++ b/option.go
@@ -0,0 +1,15 @@
+package seal
+
+import "log/slog"
+
+type Option func(auction *auction)
+
+func OptionSetLoggerLevel(level slog.Level) Option {
+	return func(_ *auction) {
+		slog.SetLogLoggerLevel(level)
+	}
+}
+
+func OptionDebug() Option {
+	return OptionSetLoggerLevel(slog.LevelDebug)
+}