package main

import (
    "fmt"
    "github.com/luxfi/crypto/kzg4844"
)

func main() {
    // Create a blob (128 KB)
    var blob kzg4844.Blob
    copy(blob[:], []byte("Your data here..."))

    // Generate commitment
    commitment, err := kzg4844.BlobToCommitment(&blob)
    if err != nil {
        panic(err)
    }

    fmt.Printf("Commitment: %x\n", commitment[:])
    fmt.Printf("Commitment size: %d bytes\n", len(commitment))
}

func computeKZGProof(blob *kzg4844.Blob, point kzg4844.Point) (kzg4844.Proof, kzg4844.Claim, error) {
    // Compute proof at specific point
    proof, claim, err := kzg4844.ComputeProof(blob, point)
    if err != nil {
        return kzg4844.Proof{}, kzg4844.Claim{}, err
    }

    fmt.Printf("Proof: %x\n", proof[:])
    fmt.Printf("Claimed value: %x\n", claim[:])

    return proof, claim, nil
}

func computeBlobProof(blob *kzg4844.Blob, commitment kzg4844.Commitment) (kzg4844.Proof, error) {
    // Compute proof for entire blob
    proof, err := kzg4844.ComputeBlobProof(blob, commitment)
    if err != nil {
        return kzg4844.Proof{}, err
    }

    return proof, nil
}

// Verify point evaluation proof
func verifyPointProof(
    commitment kzg4844.Commitment,
    point kzg4844.Point,
    claim kzg4844.Claim,
    proof kzg4844.Proof,
) bool {
    err := kzg4844.VerifyProof(commitment, point, claim, proof)
    return err == nil
}

// Verify blob matches commitment
func verifyBlobProof(
    blob *kzg4844.Blob,
    commitment kzg4844.Commitment,
    proof kzg4844.Proof,
) bool {
    err := kzg4844.VerifyBlobProof(blob, commitment, proof)
    return err == nil
}

// Compute all cell proofs for a blob
func computeCellProofs(blob *kzg4844.Blob) ([]kzg4844.Proof, error) {
    proofs, err := kzg4844.ComputeCellProofs(blob)
    if err != nil {
        return nil, err
    }

    fmt.Printf("Generated %d cell proofs\n", len(proofs))
    return proofs, nil
}

// Batch verify cell proofs
func verifyCellProofs(
    blobs []kzg4844.Blob,
    commitments []kzg4844.Commitment,
    proofs []kzg4844.Proof,
) bool {
    err := kzg4844.VerifyCellProofs(blobs, commitments, proofs)
    return err == nil
}

import (
    "crypto/sha256"
    "github.com/luxfi/crypto/kzg4844"
)

func calculateBlobHash(commitment *kzg4844.Commitment) [32]byte {
    hasher := sha256.New()
    return kzg4844.CalcBlobHashV1(hasher, commitment)
}

func isValidBlobHash(hash []byte) bool {
    return kzg4844.IsValidVersionedHash(hash)
}

// Use C-KZG backend (if available)
func useCBackend() error {
    return kzg4844.UseCKZG(true)
}

// Use Go-KZG backend
func useGoBackend() error {
    return kzg4844.UseCKZG(false)
}

type BlobTransaction struct {
    // Standard transaction fields
    ChainID    *big.Int
    Nonce      uint64
    GasTipCap  *big.Int
    GasFeeCap  *big.Int
    Gas        uint64
    To         *common.Address
    Value      *big.Int
    Data       []byte

    // Blob-specific fields
    BlobFeeCap *big.Int
    BlobHashes []common.Hash

    // Sidecar (not part of signed tx)
    Blobs       []kzg4844.Blob
    Commitments []kzg4844.Commitment
    Proofs      []kzg4844.Proof
}

func createBlobTx(data [][]byte) (*BlobTransaction, error) {
    tx := &BlobTransaction{
        Blobs:       make([]kzg4844.Blob, len(data)),
        Commitments: make([]kzg4844.Commitment, len(data)),
        Proofs:      make([]kzg4844.Proof, len(data)),
        BlobHashes:  make([]common.Hash, len(data)),
    }

    for i, d := range data {
        // Copy data to blob
        copy(tx.Blobs[i][:], d)

        // Compute commitment
        commitment, err := kzg4844.BlobToCommitment(&tx.Blobs[i])
        if err != nil {
            return nil, err
        }
        tx.Commitments[i] = commitment

        // Compute proof
        proof, err := kzg4844.ComputeBlobProof(&tx.Blobs[i], commitment)
        if err != nil {
            return nil, err
        }
        tx.Proofs[i] = proof

        // Calculate versioned hash
        hasher := sha256.New()
        tx.BlobHashes[i] = kzg4844.CalcBlobHashV1(hasher, &commitment)
    }

    return tx, nil
}

func validateBlobTx(tx *BlobTransaction) error {
    if len(tx.Blobs) != len(tx.Commitments) ||
       len(tx.Blobs) != len(tx.Proofs) ||
       len(tx.Blobs) != len(tx.BlobHashes) {
        return errors.New("mismatched blob sidecar lengths")
    }

    for i := range tx.Blobs {
        // Verify commitment matches blob
        expectedCommitment, err := kzg4844.BlobToCommitment(&tx.Blobs[i])
        if err != nil {
            return err
        }
        if expectedCommitment != tx.Commitments[i] {
            return errors.New("commitment mismatch")
        }

        // Verify proof
        if err := kzg4844.VerifyBlobProof(&tx.Blobs[i], tx.Commitments[i], tx.Proofs[i]); err != nil {
            return fmt.Errorf("proof verification failed: %w", err)
        }

        // Verify versioned hash
        hasher := sha256.New()
        expectedHash := kzg4844.CalcBlobHashV1(hasher, &tx.Commitments[i])
        if tx.BlobHashes[i] != expectedHash {
            return errors.New("blob hash mismatch")
        }
    }

    return nil
}

type DataAvailabilitySampler struct {
    commitments []kzg4844.Commitment
    cellProofs  [][]kzg4844.Proof
}

func (das *DataAvailabilitySampler) Sample(numSamples int) (bool, error) {
    for i := 0; i < numSamples; i++ {
        // Random blob index
        blobIdx := rand.Intn(len(das.commitments))

        // Random cell index
        cellIdx := rand.Intn(kzg4844.CellProofsPerBlob)

        // Verify cell proof
        // This would require the cell data and use VerifyCellProofs
        // Simplified here for illustration
    }

    return true, nil
}

// The trusted setup is embedded in the package
//go:embed trusted_setup.json
var content embed.FS

// Powers of tau ceremony parameters:
// - 4096 G1 points
// - 65 G2 points
// - Secure multi-party computation ceremony

// KZG commitments are binding - cannot find two different
// polynomials that hash to the same commitment
func demonstrateBinding() {
    var blob1, blob2 kzg4844.Blob

    // Different data produces different commitments
    copy(blob1[:], []byte("data1"))
    copy(blob2[:], []byte("data2"))

    c1, _ := kzg4844.BlobToCommitment(&blob1)
    c2, _ := kzg4844.BlobToCommitment(&blob2)

    // c1 != c2 (with overwhelming probability)
}

// Cannot forge proofs for incorrect evaluations
func verifyWithSecurityChecks(
    commitment kzg4844.Commitment,
    point kzg4844.Point,
    claim kzg4844.Claim,
    proof kzg4844.Proof,
) error {
    // Verify commitment is on curve
    if !isValidG1Point(commitment[:]) {
        return errors.New("invalid commitment point")
    }

    // Verify proof is on curve
    if !isValidG1Point(proof[:]) {
        return errors.New("invalid proof point")
    }

    // Verify the actual proof
    return kzg4844.VerifyProof(commitment, point, claim, proof)
}

type BlobCarryingBlock struct {
    Header        *BlockHeader
    Transactions  []*Transaction
    BlobSidecars  []*BlobSidecar
}

type BlobSidecar struct {
    BlobIndex   uint64
    Blob        kzg4844.Blob
    Commitment  kzg4844.Commitment
    Proof       kzg4844.Proof
    TxHash      common.Hash
}