Add openai codex support

internal/auth/codex/jwt_parser.go

@@ -0,0 +1,89 @@
+package codex
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"strings"
+	"time"
+)
+
+// JWTClaims represents the claims section of a JWT token
+type JWTClaims struct {
+	AtHash        string        `json:"at_hash"`
+	Aud           []string      `json:"aud"`
+	AuthProvider  string        `json:"auth_provider"`
+	AuthTime      int           `json:"auth_time"`
+	Email         string        `json:"email"`
+	EmailVerified bool          `json:"email_verified"`
+	Exp           int           `json:"exp"`
+	CodexAuthInfo CodexAuthInfo `json:"https://api.openai.com/auth"`
+	Iat           int           `json:"iat"`
+	Iss           string        `json:"iss"`
+	Jti           string        `json:"jti"`
+	Rat           int           `json:"rat"`
+	Sid           string        `json:"sid"`
+	Sub           string        `json:"sub"`
+}
+type Organizations struct {
+	ID        string `json:"id"`
+	IsDefault bool   `json:"is_default"`
+	Role      string `json:"role"`
+	Title     string `json:"title"`
+}
+type CodexAuthInfo struct {
+	ChatgptAccountID               string          `json:"chatgpt_account_id"`
+	ChatgptPlanType                string          `json:"chatgpt_plan_type"`
+	ChatgptSubscriptionActiveStart any             `json:"chatgpt_subscription_active_start"`
+	ChatgptSubscriptionActiveUntil any             `json:"chatgpt_subscription_active_until"`
+	ChatgptSubscriptionLastChecked time.Time       `json:"chatgpt_subscription_last_checked"`
+	ChatgptUserID                  string          `json:"chatgpt_user_id"`
+	Groups                         []any           `json:"groups"`
+	Organizations                  []Organizations `json:"organizations"`
+	UserID                         string          `json:"user_id"`
+}
+
+// ParseJWTToken parses a JWT token and extracts the claims without verification
+// This is used for extracting user information from ID tokens
+func ParseJWTToken(token string) (*JWTClaims, error) {
+	parts := strings.Split(token, ".")
+	if len(parts) != 3 {
+		return nil, fmt.Errorf("invalid JWT token format: expected 3 parts, got %d", len(parts))
+	}
+
+	// Decode the claims (payload) part
+	claimsData, err := base64URLDecode(parts[1])
+	if err != nil {
+		return nil, fmt.Errorf("failed to decode JWT claims: %w", err)
+	}
+
+	var claims JWTClaims
+	if err = json.Unmarshal(claimsData, &claims); err != nil {
+		return nil, fmt.Errorf("failed to unmarshal JWT claims: %w", err)
+	}
+
+	return &claims, nil
+}
+
+// base64URLDecode decodes a base64 URL-encoded string with proper padding
+func base64URLDecode(data string) ([]byte, error) {
+	// Add padding if necessary
+	switch len(data) % 4 {
+	case 2:
+		data += "=="
+	case 3:
+		data += "="
+	}
+
+	return base64.URLEncoding.DecodeString(data)
+}
+
+// GetUserEmail extracts the user email from JWT claims
+func (c *JWTClaims) GetUserEmail() string {
+	return c.Email
+}
+
+// GetAccountID extracts the user ID from JWT claims (subject)
+func (c *JWTClaims) GetAccountID() string {
+	return c.CodexAuthInfo.ChatgptAccountID
+}