Simplify ee_initialize function (gee-community#2162)

* Simplify ee_initialize function

* Skip ee_initialize when not needed

* Remove ee.data import

geemap/coreutils.py

@@ -42,7 +42,6 @@ def get_env_var(key: str) -> Optional[str]:
 def ee_initialize(
     token_name: str = "EARTHENGINE_TOKEN",
     auth_mode: Optional[str] = None,
-    service_account: bool = False,
     auth_args: Optional[Dict[str, Any]] = None,
     user_agent_prefix: str = "geemap",
     project: Optional[str] = None,
@@ -58,8 +57,6 @@ def ee_initialize(
             notebook, localhost, or gcloud.
             See https://developers.google.com/earth-engine/guides/auth for more
             details. Defaults to None.
-        service_account (bool, optional): If True, use a service account.
-            Defaults to False.
         auth_args (dict, optional): Additional authentication parameters for
             aa.Authenticate(). Defaults to {}.
         user_agent_prefix (str, optional): If set, the prefix (version-less)
@@ -70,17 +67,33 @@ def ee_initialize(
             For example, opt_url='https://earthengine-highvolume.googleapis.com'
             to use the Earth Engine High-Volume platform. Defaults to {}.
     """
-    import httplib2
+    import google.oauth2.credentials
     from .__init__ import __version__
 
-    if auth_args is None:
-        auth_args = {}
-
     user_agent = f"{user_agent_prefix}/{__version__}"
     ee.data.setUserAgent(user_agent)
 
-    if "http_transport" not in kwargs:
-        kwargs["http_transport"] = httplib2.Http()
+    if ee.data._credentials is not None:
+        return
+
+    ee_token = get_env_var(token_name)
+    if ee_token is not None:
+
+        stored = json.loads(ee_token)
+        credentials = google.oauth2.credentials.Credentials(
+            None,
+            token_uri="https://oauth2.googleapis.com/token",
+            client_id=stored["client_id"],
+            client_secret=stored["client_secret"],
+            refresh_token=stored["refresh_token"],
+            quota_project_id=stored["project"],
+        )
+
+        ee.Initialize(credentials=credentials, **kwargs)
+        return
+
+    if auth_args is None:
+        auth_args = {}
 
     if project is None:
         kwargs["project"] = get_env_var("EE_PROJECT_ID")
@@ -97,60 +110,8 @@ def ee_initialize(
 
     auth_args["auth_mode"] = auth_mode
 
-    if ee.data._credentials is None:
-        ee_token = get_env_var(token_name)
-        if service_account:
-            try:
-                credential_file_path = os.path.expanduser(
-                    "~/.config/earthengine/private-key.json"
-                )
-
-                if os.path.exists(credential_file_path):
-                    with open(credential_file_path) as f:
-                        token_dict = json.load(f)
-                else:
-                    token_name = "EARTHENGINE_TOKEN"
-                    ee_token = os.environ.get(token_name)
-                    token_dict = json.loads(ee_token, strict=False)
-                service_account = token_dict["client_email"]
-                private_key = token_dict["private_key"]
-
-                credentials = ee.ServiceAccountCredentials(
-                    service_account, key_data=private_key
-                )
-                ee.Initialize(credentials, **kwargs)
-
-            except Exception as e:
-                raise Exception(e)
-
-        else:
-            try:
-                if ee_token is not None:
-                    credential_file_path = os.path.expanduser(
-                        "~/.config/earthengine/credentials"
-                    )
-                    if not os.path.exists(credential_file_path):
-                        os.makedirs(
-                            os.path.dirname(credential_file_path), exist_ok=True
-                        )
-                        if ee_token.startswith("{") and ee_token.endswith(
-                            "}"
-                        ):  # deals with token generated by new auth method (earthengine-api>=0.1.304).
-                            token_dict = json.loads(ee_token)
-                            with open(credential_file_path, "w") as f:
-                                f.write(json.dumps(token_dict))
-                        else:
-                            credential = (
-                                '{"refresh_token":"%s"}' % ee_token
-                            )  # deals with token generated by old auth method.
-                            with open(credential_file_path, "w") as f:
-                                f.write(credential)
-
-                ee.Initialize(**kwargs)
-
-            except Exception:
-                ee.Authenticate(**auth_args)
-                ee.Initialize(**kwargs)
+    ee.Authenticate(**auth_args)
+    ee.Initialize(**kwargs)
 
 
 def get_info(