feat: re-linking bank accounts with plaid (#24392)

diff --git a/erpnext/accounts/doctype/bank/bank.js b/erpnext/accounts/doctype/bank/bank.js
index de9498e..49b2b18 100644
--- a/erpnext/accounts/doctype/bank/bank.js
+++ b/erpnext/accounts/doctype/bank/bank.js
@@ -1,5 +1,6 @@
 // Copyright (c) 2018, Frappe Technologies Pvt. Ltd. and contributors
 // For license information, please see license.txt
+frappe.provide('erpnext.integrations');
 
 frappe.ui.form.on('Bank', {
 	onload: function(frm) {
@@ -20,7 +21,12 @@
 			frm.set_df_property('address_and_contact', 'hidden', 0);
 			frappe.contacts.render_address_and_contact(frm);
 		}
-	},
+		if (frm.doc.plaid_access_token) {
+			frm.add_custom_button(__('Refresh Plaid Link'), () => {
+				new erpnext.integrations.refreshPlaidLink(frm.doc.plaid_access_token);
+			});
+		}
+	}
 });
 
 
@@ -40,4 +46,79 @@
 		frm.doc.name).options = options;
 
 	frm.fields_dict.bank_transaction_mapping.grid.refresh();
-};
\ No newline at end of file
+};
+
+erpnext.integrations.refreshPlaidLink = class refreshPlaidLink {
+	constructor(access_token) {
+		this.access_token = access_token;
+		this.plaidUrl = 'https://cdn.plaid.com/link/v2/stable/link-initialize.js';
+		this.init_config();
+	}
+
+	async init_config() {
+		this.plaid_env = await frappe.db.get_single_value('Plaid Settings', 'plaid_env');
+		this.token = await this.get_link_token_for_update();
+		this.init_plaid();
+	}
+
+	async get_link_token_for_update() {
+		const token = frappe.xcall(
+			'erpnext.erpnext_integrations.doctype.plaid_settings.plaid_settings.get_link_token_for_update',
+			{ access_token: this.access_token }
+		)
+		if (!token) {
+			frappe.throw(__('Cannot retrieve link token for update. Check Error Log for more information'));
+		}
+		return token;
+	}
+
+	init_plaid() {
+		const me = this;
+		me.loadScript(me.plaidUrl)
+			.then(() => {
+				me.onScriptLoaded(me);
+			})
+			.then(() => {
+				if (me.linkHandler) {
+					me.linkHandler.open();
+				}
+			})
+			.catch((error) => {
+				me.onScriptError(error);
+			});
+	}
+
+	loadScript(src) {
+		return new Promise(function (resolve, reject) {
+			if (document.querySelector("script[src='" + src + "']")) {
+				resolve();
+				return;
+			}
+			const el = document.createElement('script');
+			el.type = 'text/javascript';
+			el.async = true;
+			el.src = src;
+			el.addEventListener('load', resolve);
+			el.addEventListener('error', reject);
+			el.addEventListener('abort', reject);
+			document.head.appendChild(el);
+		});
+	}
+
+	onScriptLoaded(me) {
+		me.linkHandler = Plaid.create({
+			env: me.plaid_env,
+			token: me.token,
+			onSuccess: me.plaid_success
+		});
+	}
+
+	onScriptError(error) {
+		frappe.msgprint(__("There was an issue connecting to Plaid's authentication server. Check browser console for more information"));
+		console.log(error);
+	}
+
+	plaid_success(token, response) {
+		frappe.show_alert({ message: __('Plaid Link Updated'), indicator: 'green' });
+	}
+};
diff --git a/erpnext/erpnext_integrations/doctype/plaid_settings/plaid_connector.py b/erpnext/erpnext_integrations/doctype/plaid_settings/plaid_connector.py
index 8d4b510..66d0e5f 100644
--- a/erpnext/erpnext_integrations/doctype/plaid_settings/plaid_connector.py
+++ b/erpnext/erpnext_integrations/doctype/plaid_settings/plaid_connector.py
@@ -29,14 +29,11 @@
 		response = self.client.Item.public_token.exchange(public_token)
 		access_token = response["access_token"]
 		return access_token
-
-	def get_link_token(self):
+	
+	def get_token_request(self, update_mode=False):
 		country_codes = ["US", "CA", "FR", "IE", "NL", "ES", "GB"] if self.settings.enable_european_access else ["US", "CA"]
-		token_request = {
+		args = {
 			"client_name": self.client_name,
-			"client_id": self.settings.plaid_client_id,
-			"secret": self.settings.plaid_secret,
-			"products": self.products,
 			# only allow Plaid-supported languages and countries (LAST: Sep-19-2020)
 			"language": frappe.local.lang if frappe.local.lang in ["en", "fr", "es", "nl"] else "en",
 			"country_codes": country_codes,
@@ -45,6 +42,20 @@
 			}
 		}
 
+		if update_mode:
+			args["access_token"] = self.access_token
+		else:
+			args.update({
+				"client_id": self.settings.plaid_client_id,
+				"secret": self.settings.plaid_secret,
+				"products": self.products,
+			})
+		
+		return args
+
+	def get_link_token(self, update_mode=False):
+		token_request = self.get_token_request(update_mode)
+
 		try:
 			response = self.client.LinkToken.create(token_request)
 		except InvalidRequestError:
diff --git a/erpnext/erpnext_integrations/doctype/plaid_settings/plaid_settings.js b/erpnext/erpnext_integrations/doctype/plaid_settings/plaid_settings.js
index f26b130..bbc2ca8 100644
--- a/erpnext/erpnext_integrations/doctype/plaid_settings/plaid_settings.js
+++ b/erpnext/erpnext_integrations/doctype/plaid_settings/plaid_settings.js
@@ -12,7 +12,7 @@
 
 	refresh: function (frm) {
 		if (frm.doc.enabled) {
-			frm.add_custom_button('Link a new bank account', () => {
+			frm.add_custom_button(__('Link a new bank account'), () => {
 				new erpnext.integrations.plaidLink(frm);
 			});
 
@@ -46,10 +46,18 @@
 		this.product = ["auth", "transactions"];
 		this.plaid_env = this.frm.doc.plaid_env;
 		this.client_name = frappe.boot.sitename;
-		this.token = await this.frm.call("get_link_token").then(resp => resp.message);
+		this.token = await this.get_link_token();
 		this.init_plaid();
 	}
 
+	async get_link_token() {
+		const token = await this.frm.call("get_link_token").then(resp => resp.message);
+		if (!token) {
+			frappe.throw(__('Cannot retrieve link token. Check Error Log for more information'));
+		}
+		return token;
+	}
+
 	init_plaid() {
 		const me = this;
 		me.loadScript(me.plaidUrl)
@@ -94,8 +102,8 @@
 	}
 
 	onScriptError(error) {
-		frappe.msgprint("There was an issue connecting to Plaid's authentication server");
-		frappe.msgprint(error);
+		frappe.msgprint(__("There was an issue connecting to Plaid's authentication server. Check browser console for more information"));
+		console.log(error);
 	}
 
 	plaid_success(token, response) {
@@ -123,4 +131,4 @@
 			});
 		}, __("Select a company"), __("Continue"));
 	}
-};
+};
\ No newline at end of file
diff --git a/erpnext/erpnext_integrations/doctype/plaid_settings/plaid_settings.py b/erpnext/erpnext_integrations/doctype/plaid_settings/plaid_settings.py
index e12d9ee..70c7f3f 100644
--- a/erpnext/erpnext_integrations/doctype/plaid_settings/plaid_settings.py
+++ b/erpnext/erpnext_integrations/doctype/plaid_settings/plaid_settings.py
@@ -230,7 +230,6 @@
 	if settings.enabled == 1 and settings.automatic_sync == 1:
 		enqueue_synchronization()
 
-
 @frappe.whitelist()
 def enqueue_synchronization():
 	plaid_accounts = frappe.get_all("Bank Account",
@@ -243,3 +242,8 @@
 			bank=plaid_account.bank,
 			bank_account=plaid_account.name
 		)
+
+@frappe.whitelist()
+def get_link_token_for_update(access_token):
+	plaid = PlaidConnector(access_token)
+	return plaid.get_link_token(update_mode=True)