synapsecns/sanguine

package attestation

import (
    "context"
    "encoding/json"
    "fmt"
    "io"
    "net/http"

    "github.com/ethereum/go-ethereum/common/hexutil"
)

// CircleAPI is a wrapper for Circle's REST API.
type CircleAPI struct {
    client  *http.Client
    baseURL string
}

const circleAttestationURL = "https://iris-api.circle.com/v1/attestations"

// NewCircleAPI creates a new CircleAPI.
func NewCircleAPI(url string) CircleAPI {
    if url == "" {
        url = circleAttestationURL
    }
    return CircleAPI{
        client:  &http.Client{},
        baseURL: url,
    }
}

type circleAttestationResponse struct {
    Attestation string `json:"attestation"`
    Status      string `json:"status"`
}

// GetAttestation is a wrapper for GET /attestations/{txHash}.
func (c CircleAPI) GetAttestation(ctx context.Context, txHash string) (attestation []byte, err error) {
    url := fmt.Sprintf("%s/%s", c.baseURL, txHash)
    req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
    if err != nil {
        err = fmt.Errorf("could not create request: %w", err)
        return
    }

    resp, err := c.client.Do(req)
    if err != nil {
        return
    }
    //nolint:errcheck
    defer resp.Body.Close()

    if resp.StatusCode != http.StatusOK {
        err = fmt.Errorf("received non-200 status code: %d", resp.StatusCode)
        return
    }

    body, err := io.ReadAll(resp.Body)
    if err != nil {
        return
    }

    var attestationResp circleAttestationResponse
    err = json.Unmarshal(body, &attestationResp)
    if err != nil {
        return nil, fmt.Errorf("could not unmarshal body: %w", err)
    }

    // TODO: check status
    attestation, err = hexutil.Decode(attestationResp.Attestation)
    if err != nil {
        return nil, fmt.Errorf("could not decode signature: %w", err)
    }
    return attestation, nil
}

var _ CCTPAPI = &CircleAPI{}