4 files changed, 184 insertions, 0 deletions
diff --git a/packages/backend/src/utils/amount.ts b/packages/backend/src/utils/amount.ts
new file mode 100644
index 0000000..062ddaf
--- /dev/null
+++ b/packages/backend/src/utils/amount.ts
@@ -0,0 +1,69 @@
+/*
+ This file is part of GNU Taler
+ (C) 2021 Taler Systems S.A.
+
+ GNU Taler is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+import { amountFractionalBase, AmountJson, Amounts } from "@gnu-taler/taler-util";
+import { MerchantBackend } from "../declaration";
+
+/**
+ * sums two prices, 
+ * @param one 
+ * @param two 
+ * @returns 
+ */
+const sumPrices = (one: string, two: string) => {
+  const [currency, valueOne] = one.split(':')
+  const [, valueTwo] = two.split(':')
+  return `${currency}:${parseInt(valueOne, 10) + parseInt(valueTwo, 10)}`
+}
+
+/**
+ * merge refund with the same description and a difference less than one minute
+ * @param prev list of refunds that will hold the merged refunds 
+ * @param cur new refund to add to the list
+ * @returns list with the new refund, may be merged with the last
+ */
+export function mergeRefunds(prev: MerchantBackend.Orders.RefundDetails[], cur: MerchantBackend.Orders.RefundDetails) {
+  let tail;
+
+  if (prev.length === 0 ||  //empty list
+    cur.timestamp.t_ms === 'never' || //current doesnt have timestamp
+    (tail = prev[prev.length - 1]).timestamp.t_ms === 'never' || // last doesnt have timestamp
+    cur.reason !== tail.reason || //different reason
+    Math.abs(cur.timestamp.t_ms - tail.timestamp.t_ms) > 1000 * 60) {//more than 1 minute difference
+
+    prev.push(cur)
+    return prev
+  }
+
+  prev[prev.length - 1] = {
+    ...tail,
+    amount: sumPrices(tail.amount, cur.amount)
+  }
+
+  return prev
+}
+
+export const rate = (one: string, two: string) => {
+  const a = Amounts.parseOrThrow(one)
+  const b = Amounts.parseOrThrow(two)
+  const af = toFloat(a)
+  const bf = toFloat(b)
+  if (bf === 0) return 0
+  return af / bf
+}
+
+function toFloat(amount: AmountJson) {
+  return amount.value + (amount.fraction / amountFractionalBase);
+}
diff --git a/packages/backend/src/utils/constants.ts b/packages/backend/src/utils/constants.ts
new file mode 100644
index 0000000..37c46e4
--- /dev/null
+++ b/packages/backend/src/utils/constants.ts
@@ -0,0 +1,47 @@
+/*
+ This file is part of GNU Taler
+ (C) 2021 Taler Systems S.A.
+
+ GNU Taler is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+/**
+*
+* @author Sebastian Javier Marchano (sebasjm)
+*/
+
+//https://tools.ietf.org/html/rfc8905
+export const PAYTO_REGEX = /^payto:\/\/[a-zA-Z][a-zA-Z0-9-.]+(\/[a-zA-Z0-9\-\.\~\(\)@_%:!$&'*+,;=]*)*\??((amount|receiver-name|sender-name|instruction|message)=[a-zA-Z0-9\-\.\~\(\)@_%:!$'*+,;=]*&?)*$/
+export const PAYTO_WIRE_METHOD_LOOKUP = /payto:\/\/([a-zA-Z][a-zA-Z0-9-.]+)\/.*/
+
+export const AMOUNT_REGEX = /^[a-zA-Z][a-zA-Z]*:[0-9][0-9,]*\.?[0-9,]*$/
+
+export const INSTANCE_ID_LOOKUP = /^\/instances\/([^/]*)\/?$/
+
+export const AMOUNT_ZERO_REGEX = /^[a-zA-Z][a-zA-Z]*:0$/
+
+export const CROCKFORD_BASE32_REGEX = /^[0123456789ABCDEFGHJKMNPQRSTVWXYZ]+[*~$=U]*$/
+
+export const URL_REGEX = /^((https?:)(\/\/\/?)([\w]*(?::[\w]*)?@)?([\d\w\.-]+)(?::(\d+))?)\/$/
+
+// how much rows we add every time user hit load more
+export const PAGE_SIZE = 20
+// how bigger can be the result set
+// after this threshold, load more with move the cursor
+export const MAX_RESULT_SIZE = PAGE_SIZE * 2 - 1;
+
+// how much we will wait for all request, in seconds
+export const DEFAULT_REQUEST_TIMEOUT = 10;
+
+export const MAX_IMAGE_SIZE = 1024 * 1024;
+
+export const INSTANCE_ID_REGEX = /^[a-zA-Z0-9][a-zA-Z0-9_.@-]+$/
diff --git a/packages/backend/src/utils/table.ts b/packages/backend/src/utils/table.ts
new file mode 100644
index 0000000..3d713a6
--- /dev/null
+++ b/packages/backend/src/utils/table.ts
@@ -0,0 +1,37 @@
+/*
+ This file is part of GNU Taler
+ (C) 2021 Taler Systems S.A.
+
+ GNU Taler is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+import { WithId } from "../declaration";
+
+/**
+*
+* @author Sebastian Javier Marchano (sebasjm)
+*/
+
+export interface Actions<T extends WithId> {
+  element: T;
+  type: 'DELETE' | 'UPDATE';
+}
+
+function notEmpty<TValue>(value: TValue | null | undefined): value is TValue {
+  return value !== null && value !== undefined;
+}
+
+export function buildActions<T extends WithId>(intances: T[], selected: string[], action: 'DELETE'): Actions<T>[] {
+  return selected.map(id => intances.find(i => i.id === id))
+    .filter(notEmpty)
+    .map(id => ({ element: id, type: action }))
+}
diff --git a/packages/backend/src/utils/types.ts b/packages/backend/src/utils/types.ts
new file mode 100644
index 0000000..9e49d39
--- /dev/null
+++ b/packages/backend/src/utils/types.ts
@@ -0,0 +1,31 @@
+/*
+ This file is part of GNU Taler
+ (C) 2021 Taler Systems S.A.
+
+ GNU Taler is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+import { VNode } from "preact"
+
+export interface KeyValue {
+  [key: string]: string;
+}
+
+export interface Notification {
+  message: string;
+  description?: string | VNode;
+  type: MessageType;
+}
+
+export type ValueOrFunction<T> = T | ((p: T) => T)
+export type MessageType = 'INFO' | 'WARN' | 'ERROR' | 'SUCCESS'
+