From a6f24042f5edf1c5b3876f51aa72ea4e6bdf8682 Mon Sep 17 00:00:00 2001
From: Mohammed Sohail <sohailsameja@gmail.com>
Date: Fri, 29 Apr 2022 17:04:01 +0300
Subject: [PATCH] add: cic-meta client

---
 pkg/meta/meta.go | 113 +++++++++++++++++++++++++++++++++++++++++++++++
 pkg/meta/util.go |  50 +++++++++++++++++++++
 2 files changed, 163 insertions(+)
 create mode 100644 pkg/meta/meta.go
 create mode 100644 pkg/meta/util.go

diff --git a/pkg/meta/meta.go b/pkg/meta/meta.go
new file mode 100644
index 0000000..a549297
--- /dev/null
+++ b/pkg/meta/meta.go
@@ -0,0 +1,113 @@
+package meta
+
+import (
+	"github.com/ethereum/go-ethereum/common"
+	"net/http"
+	"strings"
+	"time"
+)
+
+const (
+	personPointer      = ":cic.person"
+	phonePointer       = ":cic.phone"
+	preferencesPointer = ":cic.preferences"
+	customPointer      = ":cic.custom"
+)
+
+type CicMeta struct {
+	httpClient *http.Client
+	baseUrl    string
+}
+
+type CustomResponse struct {
+	Tags []string `json:"tags"`
+}
+
+type PreferencesResponse struct {
+	PreferredLanguage string `json:"preferred_language"`
+}
+
+type PersonResponse struct {
+	DateRegistered int         `json:"date_registered"`
+	VCard          string      `json:"vcard"`
+	Gender         string      `json:"gender"`
+	Location       Location    `json:"location"`
+	Products       []string    `json:"products"`
+	DateOfBirth    DateOfBirth `json:"date_of_birth"`
+}
+
+type Location struct {
+	AreaName string `json:"area_name"`
+}
+
+type DateOfBirth struct {
+	Year int `json:"year"`
+}
+
+func NewCicMeta(metaEndpoint string) *CicMeta {
+	return &CicMeta{
+		httpClient: &http.Client{
+			Timeout: time.Second * 3,
+		},
+		baseUrl: metaEndpoint,
+	}
+}
+
+func (c *CicMeta) GetPhonePointer(phone string) (string, error) {
+	hashedKey := mergeSha256Key([]byte(phone), []byte(phonePointer))
+
+	r, err := requestHandler(c, hashedKey)
+	if err != nil {
+		return "", err
+	}
+
+	return strings.Trim(string(r), "\""), nil
+}
+
+func (c *CicMeta) GetPersonMetadata(address string) (PersonResponse, error) {
+	hashedKey := mergeSha256Key(common.HexToAddress(address).Bytes(), []byte(personPointer))
+
+	respData, err := requestHandler(c, hashedKey)
+	if err != nil {
+		return PersonResponse{}, err
+	}
+
+	metadata, err := jsonUnmarshaler(respData, PersonResponse{})
+	if err != nil {
+		return PersonResponse{}, err
+	}
+
+	return metadata, nil
+}
+
+func (c *CicMeta) GetPreferencesMetadata(address string) (PreferencesResponse, error) {
+	hashedKey := mergeSha256Key(common.HexToAddress(address).Bytes(), []byte(preferencesPointer))
+
+	respData, err := requestHandler(c, hashedKey)
+	if err != nil {
+		return PreferencesResponse{}, err
+	}
+
+	metadata, err := jsonUnmarshaler(respData, PreferencesResponse{})
+	if err != nil {
+		return PreferencesResponse{}, err
+	}
+
+	return metadata, nil
+}
+
+func (c *CicMeta) GetCustomMetadata(address string) (CustomResponse, error) {
+	hashedKey := mergeSha256Key(common.HexToAddress(address).Bytes(), []byte(customPointer))
+
+	respData, err := requestHandler(c, hashedKey)
+	if err != nil {
+		return CustomResponse{}, err
+	}
+
+	metadata, err := jsonUnmarshaler(respData, CustomResponse{})
+	if err != nil {
+		return CustomResponse{}, err
+	}
+
+	return metadata, nil
+}
diff --git a/pkg/meta/util.go b/pkg/meta/util.go
new file mode 100644
index 0000000..b521fc1
--- /dev/null
+++ b/pkg/meta/util.go
@@ -0,0 +1,50 @@
+package meta
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+)
+
+func generateMetaUrl(metaBaseUrl string, key string) string {
+	return fmt.Sprintf("%s/%s", metaBaseUrl, key)
+}
+
+func mergeSha256Key(x []byte, y []byte) string {
+	h := sha256.New()
+
+	h.Write(x)
+	h.Write(y)
+
+	return hex.EncodeToString(h.Sum(nil))
+}
+
+func requestHandler(cicMeta *CicMeta, metadataKey string) ([]byte, error) {
+	resp, err := cicMeta.httpClient.Get(generateMetaUrl(cicMeta.baseUrl, metadataKey))
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("error fetching metadata for key %s: %s", metadataKey, resp.Status)
+	}
+
+	respData, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	return respData, nil
+}
+
+func jsonUnmarshaler[T PersonResponse | PreferencesResponse | CustomResponse](respBody []byte, binding T) (T, error) {
+	if err := json.Unmarshal(respBody, &binding); err != nil {
+		return binding, err
+	}
+
+	return binding, nil
+}