feat: refactor invoice_discounting (#18629)

* feat: refactor invoice_discountig

* Update invoice_discounting.py

* Update invoice_discounting.js
diff --git a/erpnext/accounts/doctype/discounted_invoice/discounted_invoice.json b/erpnext/accounts/doctype/discounted_invoice/discounted_invoice.json
index 8d7ed74..04d6303 100644
--- a/erpnext/accounts/doctype/discounted_invoice/discounted_invoice.json
+++ b/erpnext/accounts/doctype/discounted_invoice/discounted_invoice.json
@@ -8,7 +8,8 @@
   "customer",
   "column_break_3",
   "posting_date",
-  "outstanding_amount"
+  "outstanding_amount",
+  "debit_to"
  ],
  "fields": [
   {
@@ -48,10 +49,18 @@
   {
    "fieldname": "column_break_3",
    "fieldtype": "Column Break"
+  },
+  {
+   "fetch_from": "sales_invoice.debit_to",
+   "fieldname": "debit_to",
+   "fieldtype": "Link",
+   "label": "Debit to",
+   "options": "Account",
+   "read_only": 1
   }
  ],
  "istable": 1,
- "modified": "2019-05-30 19:27:29.436153",
+ "modified": "2019-08-07 15:13:55.808349",
  "modified_by": "Administrator",
  "module": "Accounts",
  "name": "Discounted Invoice",
diff --git a/erpnext/accounts/doctype/invoice_discounting/invoice_discounting.js b/erpnext/accounts/doctype/invoice_discounting/invoice_discounting.js
index 5563f03..f1f88a8 100644
--- a/erpnext/accounts/doctype/invoice_discounting/invoice_discounting.js
+++ b/erpnext/accounts/doctype/invoice_discounting/invoice_discounting.js
@@ -13,41 +13,57 @@
 			};
 		});
 
-		frm.events.filter_accounts("bank_account", frm, {"account_type": "Bank"});
-		frm.events.filter_accounts("bank_charges_account", frm, {"root_type": "Expense"});
-		frm.events.filter_accounts("short_term_loan", frm, {"root_type": "Liability"});
-		frm.events.filter_accounts("accounts_receivable_credit", frm, {"account_type": "Receivable"});
-		frm.events.filter_accounts("accounts_receivable_discounted", frm, {"account_type": "Receivable"});
-		frm.events.filter_accounts("accounts_receivable_unpaid", frm, {"account_type": "Receivable"});
+
+		frm.events.filter_accounts("bank_account", frm, [["account_type", "=", "Bank"]]);
+		frm.events.filter_accounts("bank_charges_account", frm, [["root_type", "=", "Expense"]]);
+		frm.events.filter_accounts("short_term_loan", frm, [["root_type", "=", "Liability"]]);
+		frm.events.filter_accounts("accounts_receivable_discounted", frm, [["account_type", "=", "Receivable"]]);
+		frm.events.filter_accounts("accounts_receivable_credit", frm, [["account_type", "=", "Receivable"]]);
+		frm.events.filter_accounts("accounts_receivable_unpaid", frm, [["account_type", "=", "Receivable"]]);
 
 	},
 
 	filter_accounts: (fieldname, frm, addl_filters) => {
-		let filters = {
-			"company": frm.doc.company,
-			"is_group": 0
-		};
-		if(addl_filters) Object.assign(filters, addl_filters);
+		let filters = [
+			["company", "=", frm.doc.company],
+			["is_group", "=", 0]
+		];
+		if(addl_filters){
+			filters = $.merge(filters , addl_filters);
+		}
 
 		frm.set_query(fieldname, () => { return { "filters": filters }; });
 	},
 
+	refresh_filters: (frm) =>{
+		let invoice_accounts = Object.keys(frm.doc.invoices).map(function(key) {
+			return frm.doc.invoices[key].debit_to;
+		});
+		let filters = [
+			["account_type", "=", "Receivable"],
+			["name", "not in", invoice_accounts]
+		];
+		frm.events.filter_accounts("accounts_receivable_credit", frm, filters);
+		frm.events.filter_accounts("accounts_receivable_discounted", frm, filters);
+		frm.events.filter_accounts("accounts_receivable_unpaid", frm, filters);
+	},
+
 	refresh: (frm) => {
 		frm.events.show_general_ledger(frm);
 
-		if(frm.doc.docstatus === 0) {
+		if (frm.doc.docstatus === 0) {
 			frm.add_custom_button(__('Get Invoices'), function() {
 				frm.events.get_invoices(frm);
 			});
 		}
 
-		if(frm.doc.docstatus === 1 && frm.doc.status !== "Settled") {
-			if(frm.doc.status == "Sanctioned") {
+		if (frm.doc.docstatus === 1 && frm.doc.status !== "Settled") {
+			if (frm.doc.status == "Sanctioned") {
 				frm.add_custom_button(__('Disburse Loan'), function() {
 					frm.events.create_disbursement_entry(frm);
 				}).addClass("btn-primary");
 			}
-			if(frm.doc.status == "Disbursed") {
+			if (frm.doc.status == "Disbursed") {
 				frm.add_custom_button(__('Close Loan'), function() {
 					frm.events.close_loan(frm);
 				}).addClass("btn-primary");
@@ -64,7 +80,7 @@
 	},
 
 	set_end_date: (frm) => {
-		if(frm.doc.loan_start_date && frm.doc.loan_period) {
+		if (frm.doc.loan_start_date && frm.doc.loan_period) {
 			let end_date = frappe.datetime.add_days(frm.doc.loan_start_date, frm.doc.loan_period);
 			frm.set_value("loan_end_date", end_date);
 		}
@@ -132,6 +148,7 @@
 								frm.doc.invoices = frm.doc.invoices.filter(row => row.sales_invoice);
 								let row = frm.add_child("invoices");
 								$.extend(row, v);
+								frm.events.refresh_filters(frm);
 							});
 							refresh_field("invoices");
 						}
@@ -190,8 +207,10 @@
 frappe.ui.form.on('Discounted Invoice', {
 	sales_invoice: (frm) => {
 		frm.events.calculate_total_amount(frm);
+		frm.events.refresh_filters(frm);
 	},
 	invoices_remove: (frm) => {
 		frm.events.calculate_total_amount(frm);
+		frm.events.refresh_filters(frm);
 	}
-});
\ No newline at end of file
+});
diff --git a/erpnext/accounts/doctype/invoice_discounting/invoice_discounting.py b/erpnext/accounts/doctype/invoice_discounting/invoice_discounting.py
index 29475d5..36c2911 100644
--- a/erpnext/accounts/doctype/invoice_discounting/invoice_discounting.py
+++ b/erpnext/accounts/doctype/invoice_discounting/invoice_discounting.py
@@ -12,6 +12,7 @@
 class InvoiceDiscounting(AccountsController):
 	def validate(self):
 		self.validate_mandatory()
+		self.validate_invoices()
 		self.calculate_total_amount()
 		self.set_status()
 		self.set_end_date()
@@ -24,6 +25,15 @@
 		if self.docstatus == 1 and not (self.loan_start_date and self.loan_period):
 			frappe.throw(_("Loan Start Date and Loan Period are mandatory to save the Invoice Discounting"))
 
+	def validate_invoices(self):
+		discounted_invoices = [record.sales_invoice for record in 
+			frappe.get_all("Discounted Invoice",fields = ["sales_invoice"], filters= {"docstatus":1})]
+
+		for record in self.invoices:
+			if record.sales_invoice in discounted_invoices:
+				frappe.throw("Row({0}): {1} is already discounted in {2}"
+					.format(record.idx, frappe.bold(record.sales_invoice), frappe.bold(record.parent)))
+
 	def calculate_total_amount(self):
 		self.total_amount = sum([flt(d.outstanding_amount) for d in self.invoices])
 
@@ -212,7 +222,8 @@
 			name as sales_invoice,
 			customer,
 			posting_date,
-			outstanding_amount
+			outstanding_amount,
+			debit_to
 		from `tabSales Invoice` si
 		where
 			docstatus = 1