Allow users to transfer founds to another account

CHANGELOG.md

@@ -1,5 +1,18 @@
 # Matemat Changelog
 
+<!-- BEGIN RELEASE v0.2.10 -->
+## Version 0.2.10
+
+Feature release
+
+### Changes
+
+<!-- BEGIN CHANGES 0.2.10 -->
+- Feature: Let users transfer funds to another account
+<!-- END CHANGES 0.2.10 -->
+
+<!-- END RELEASE v0.2.10 -->
+
 <!-- BEGIN RELEASE v0.2.9 -->
 ## Version 0.2.9
 

matemat/__init__.py

@@ -1,2 +1,2 @@
 
-__version__ = '0.2.9'
+__version__ = '0.2.10'

matemat/db/facade.py

@@ -562,6 +562,88 @@ class MatematDatabase(object):
         # Reflect the change in the user object
         user.balance = old_balance + amount
 
+    def transfer(self, source: User, dest: User, amount: int) -> None:
+        """
+        Transfer funds from one account to another.
+
+        :param source: The user account to remove funds from.
+        :param dest: The user account to add funds to.
+        :param amount: The amount to transfer between accounts.
+        :raises DatabaseConsistencyError: If the user represented by the object does not exist.
+        """
+        if amount < 0:
+            raise ValueError('Cannot transfer a negative value')
+        with self.db.transaction() as c:
+            # First, remove amount from the source user's account
+            c.execute('''SELECT balance FROM users WHERE user_id = :user_id''',
+                      [source.id])
+            row = c.fetchone()
+            if row is None:
+                raise DatabaseConsistencyError(f'No such user: {source.id}')
+            source_old_balance: int = row[0]
+            c.execute('''
+            INSERT INTO transactions (user_id, value, old_balance)
+              VALUES (:user_id, :value, :old_balance)
+            ''', {
+                'user_id': source.id,
+                'value': -amount,
+                'old_balance': source_old_balance
+            })
+            c.execute('''
+            INSERT INTO modifications (ta_id, agent, reason)
+              VALUES (last_insert_rowid(), :user, :reason)
+            ''', {
+                'user': source.name,
+                'reason': f'Transfer to {dest.name}'
+            })
+            c.execute('''
+            UPDATE users
+            SET balance = balance - :amount
+            WHERE user_id = :user_id
+            ''', {
+                'user_id': source.id,
+                'amount': amount
+            })
+            affected = c.execute('SELECT changes()').fetchone()[0]
+            if affected != 1:
+                raise DatabaseConsistencyError(f'transfer should affect 1 users row, but affected {affected}')
+            # Then, add the amount to the destination user's account
+            c.execute('''SELECT balance FROM users WHERE user_id = :user_id''',
+                      [dest.id])
+            row = c.fetchone()
+            if row is None:
+                raise DatabaseConsistencyError(f'No such user: {dest.id}')
+            dest_old_balance: int = row[0]
+            c.execute('''
+            INSERT INTO transactions (user_id, value, old_balance)
+              VALUES (:user_id, :value, :old_balance)
+            ''', {
+                'user_id': dest.id,
+                'value': amount,
+                'old_balance': dest_old_balance
+            })
+            c.execute('''
+            INSERT INTO modifications (ta_id, agent, reason)
+              VALUES (last_insert_rowid(), :user, :reason)
+            ''', {
+                'user': source.name,
+                'reason': f'Transfer from {source.name}'
+            })
+            c.execute('''
+            UPDATE users
+            SET balance = balance + :amount
+            WHERE user_id = :user_id
+            ''', {
+                'user_id': dest.id,
+                'amount': amount
+            })
+            affected = c.execute('SELECT changes()').fetchone()[0]
+            if affected != 1:
+                raise DatabaseConsistencyError(f'deposit should affect 1 users row, but affected {affected}')
+        # Reflect the change in the user object
+        source.balance = source_old_balance - amount
+        dest.balance = dest_old_balance + amount
+
     def check_receipt_due(self, user: User) -> bool:
         if not isinstance(user.receipt_pref, ReceiptPreference):
             raise TypeError()

matemat/db/test/test_facade.py

@@ -339,6 +339,36 @@ class DatabaseTest(unittest.TestCase):
                     # Should fail, user id -1 does not exist
                     db.deposit(user, 42)
 
+    def test_transfer(self) -> None:
+        with self.db as db:
+            with db.transaction() as c:
+                user = db.create_user('testuser', 'supersecurepassword', 'testuser@example.com', True, True)
+                user2 = db.create_user('testuser2', 'supersecurepassword', 'testuser@example.com', True, True)
+                user3 = db.create_user('testuser3', 'supersecurepassword', 'testuser@example.com', True, True)
+                c.execute('''SELECT balance FROM users WHERE user_id = ?''', [user.id])
+                self.assertEqual(0, c.fetchone()[0])
+                c.execute('''SELECT balance FROM users WHERE user_id = ?''', [user2.id])
+                self.assertEqual(0, c.fetchone()[0])
+                c.execute('''SELECT balance FROM users WHERE user_id = ?''', [user3.id])
+                self.assertEqual(0, c.fetchone()[0])
+                db.transfer(user, user2, 1337)
+                c.execute('''SELECT balance FROM users WHERE user_id = ?''', [user.id])
+                self.assertEqual(-1337, c.fetchone()[0])
+                c.execute('''SELECT balance FROM users WHERE user_id = ?''', [user2.id])
+                self.assertEqual(1337, c.fetchone()[0])
+                c.execute('''SELECT balance FROM users WHERE user_id = ?''', [user3.id])
+                self.assertEqual(0, c.fetchone()[0])
+                with self.assertRaises(ValueError):
+                    # Should fail, negative amount
+                    db.transfer(user, user2, -42)
+                user.id = -1
+                with self.assertRaises(DatabaseConsistencyError):
+                    # Should fail, user id -1 does not exist
+                    db.transfer(user, user2, 42)
+                with self.assertRaises(DatabaseConsistencyError):
+                    # Should fail, user id -1 does not exist
+                    db.transfer(user2, user, 42)
+
     def test_consumption(self) -> None:
         with self.db as db:
             # Set up test case

matemat/webserver/pagelets/__init__.py

@@ -10,6 +10,7 @@ from .logout import logout
 from .touchkey import touchkey_page
 from .buy import buy
 from .deposit import deposit
+from .transfer import transfer
 from .admin import admin
 from .metrics import metrics
 from .moduser import moduser

matemat/webserver/pagelets/main.py

@@ -19,13 +19,14 @@ def main_page():
             uid: int = session.get(session_id, 'authenticated_user')
             authlevel: int = session.get(session_id, 'authentication_level')
             # Fetch the user object from the database (for name display, price calculation and admin check)
+            users = db.list_users()
             user = db.get_user(uid)
             # Fetch the list of products to display
             products = db.list_products()
             # Prepare a response with a jinja2 template
             return template.render('productlist.html',
-                                   authuser=user, products=products, authlevel=authlevel, stock=get_stock_provider(),
+                                   authuser=user, users=users, products=products, authlevel=authlevel,
-                                   setupname=config['InstanceName'])
+                                   stock=get_stock_provider(), setupname=config['InstanceName'])
         else:
             # If there are no admin users registered, jump to the admin creation procedure
             if not db.has_admin_users():

matemat/webserver/pagelets/transfer.py

@@ -0,0 +1,34 @@
+from bottle import get, post, redirect, request
+
+from matemat.db import MatematDatabase
+from matemat.webserver import session
+from matemat.webserver import config as c
+
+
+@get('/transfer')
+@post('/transfer')
+def transfer():
+    """
+    The transfer mechanism to tranfer funds between accounts.
+    """
+    config = c.get_app_config()
+    session_id: str = session.start()
+    # If no user is logged in, redirect to the main page, as a purchase must always be bound to a user
+    if not session.has(session_id, 'authenticated_user'):
+        redirect('/')
+    # Connect to the database
+    with MatematDatabase(config['DatabaseFile']) as db:
+        # Fetch the authenticated user from the database
+        uid: int = session.get(session_id, 'authenticated_user')
+        user = db.get_user(uid)
+        if 'target' not in request.params or 'n' not in request.params:
+            redirect('/')
+            return;
+        # Fetch the target user from the database
+        tuid = int(str(request.params.target))
+        transfer_user = db.get_user(tuid)
+        # Read and transfer amount between accounts
+        amount = int(str(request.params.n))
+        db.transfer(user, transfer_user, amount)
+    # Redirect to the main page (where this request should have come from)
+    redirect('/')

package/debian/matemat/DEBIAN/control

@@ -1,5 +1,5 @@
 Package: matemat
-Version: 0.2.9
+Version: 0.2.10
 Maintainer: s3lph <account-gitlab-ideynizv@kernelpanic.lol>
 Section: web
 Priority: optional

static/css/matemat.css

@@ -85,7 +85,7 @@
     margin: auto;
     width: 320px;
     height: 540px;
-    grid-template-columns: 100px 100px 100px;
+    grid-template-columns: 100px 100px 100px 200px;
     grid-template-rows: 100px 100px 100px 100px 100px;
     column-gap: 10px;
     row-gap: 10px;
@@ -196,3 +196,76 @@
     grid-row: 5;
     background: #60f060;
 }
+
+#numpad-ok.disabled {
+    background: #606060;
+}
+
+#transfer-userlist {
+    display: grid;
+    grid-column: 4;
+    grid-row-start: 1;
+    grid-row-end: 6;
+    grid-template-columns: 200px;
+    grid-template-rows: 25px 1fr 25px;
+    column-gap: 10px;
+    row-gap: 10px;
+    padding: 0;
+    margin: 0;
+}
+
+#transfer-userlist.show {
+    display: block;
+    position: relative;
+}
+
+#transfer-userlist-list {
+    margin: 10px 0;
+    padding: 0;
+    overflow-y: hidden;
+    max-height: calc(100% - 150px);
+    top: 45px;
+    bottom: 45px;
+    grid-row: 2;
+    grid-column: 1;
+}
+
+#transfer-userlist-list > li {
+    display: block;
+    background: #f0f0f0;
+    padding: 15px 20px;
+    margin-bottom: 10px;
+    list-style-type: none;
+    font-family: sans-serif;
+    line-height: 20px;
+    font-size: 20px;
+    height: 20px;
+}
+
+#transfer-userlist > #scroll-up, #transfer-userlist > #scroll-down {
+    left: 0;
+    right: 0;
+    height: 25px;
+    text-align: center;
+    display: block;
+    background: #f0f0f0;
+    padding: 20px;
+    font-family: sans-serif;
+    line-height: 25px;
+    font-size: 25px;
+}
+
+#transfer-userlist > #scroll-up{
+    grid-row: 1;
+    grid-column: 1;
+    top: 0;
+}
+#transfer-userlist > #scroll-down {
+    grid-row: 2;
+    grid-column: 1;
+    bottom: 0;
+}
+
+#transfer-userlist-list > li.active {
+    background: #60f060;
+}

static/js/depositlist.js

@@ -4,39 +4,99 @@ Number.prototype.pad = function(size) {
   return s;
 }
 
+const Mode = {
+	Deposit: 0,
+	Buy: 1,
+	Transfer: 2,
+}
+
+let mode = Mode.Deposit;
 let product_id = null;
+let target_user = null;
+let target_user_li = null;
 let deposit = '0';
 let button = document.createElement('div');
+let button_transfer = document.createElement('div');
 let input = document.getElementById('deposit-wrapper');
 let amount = document.getElementById('deposit-amount');
 let title = document.getElementById('deposit-title');
+let userlist = document.getElementById('transfer-userlist');
+let userlist_list = document.getElementById('transfer-userlist-list');
+let ok_button = document.getElementById('numpad-ok');
 button.classList.add('thumblist-item');
 button.classList.add('fakelink');
 button.innerText = 'Deposit';
 button.onclick = (ev) => {
+	mode = Mode.Deposit;
     product_id = null;
+	target_user = null;
     deposit = '0';
     title.innerText = 'Deposit';
     amount.innerText = (Math.floor(parseInt(deposit) / 100)) + '.' + (parseInt(deposit) % 100).pad();
     input.classList.add('show');
+	userlist.classList.remove('show');
+	ok_button.classList.remove('disabled');
+};
+button_transfer.classList.add('thumblist-item');
+button_transfer.classList.add('fakelink');
+button_transfer.innerText = 'Transfer';
+button_transfer.onclick = (ev) => {
+	mode = Mode.Transfer;
+    product_id = null;
+	target_user = null;
+    deposit = '0';
+    title.innerText = 'Transfer';
+    amount.innerText = (Math.floor(parseInt(deposit) / 100)) + '.' + (parseInt(deposit) % 100).pad();
+    input.classList.add('show');
+	userlist.classList.add('show');
+	ok_button.classList.add('disabled');
 };
 setup_custom_price = (pid, pname) => {
+	mode = Mode.Buy;
     product_id = pid;
+	target_user = null;
     title.innerText = pname;
     deposit = '0';
     amount.innerText = (Math.floor(parseInt(deposit) / 100)) + '.' + (parseInt(deposit) % 100).pad();
     input.classList.add('show');
+	userlist.classList.remove('show');
+	ok_button.classList.remove('disabled');
 };
+set_transfer_user = (li, uid) => {
+	if (target_user_li != null) {
+		target_user_li.classList.remove('active');
+	}
+	target_user = uid;
+	target_user_li = li;
+	ok_button.classList.remove('disabled');
+	target_user_li.classList.add('active');
+
+}
+scrollUserlist = (delta) => {
+	userlist_list.scrollBy(0, delta);
+}
 deposit_key = (k) => {
 	if (k == 'ok') {
-	if (product_id === null) {
+		switch (mode) {
+		case Mode.Deposit:
 			window.location.href = '/deposit?n=' + parseInt(deposit);
-	} else {
+			break;
+		case Mode.Buy:
 			window.location.href = '/buy?pid=' + product_id + '&price=' + parseInt(deposit);
+			break;
+		case Mode.Transfer:
+			if (target_user == null) {
+				return;
 			}
+			window.location.href = '/transfer?target=' + target_user + '&n=' + parseInt(deposit);
+			break;
+		}
+		mode = Mode.Deposit;
 		deposit = '0';
 		product_id = null;
+		target_user = null;
 		input.classList.remove('show');
+		userlist.classList.remove('show');
     } else if (k == 'del') {
 		if (deposit == '0') {
 			product_id = null;
@@ -60,3 +120,4 @@ deposit_key = (k) => {
 let list = document.getElementById('depositlist');
 list.innerHTML = '';
 list.appendChild(button);
+list.appendChild(button_transfer);

templates/productlist.html

@@ -33,6 +33,15 @@
             {% for i in [('1', '1'), ('2', '2'), ('3', '3'), ('4', '4'), ('5', '5'), ('6', '6'), ('7', '7'), ('8', '8'), ('9', '9'), ('del', '✗'), ('0', '0'), ('ok', '✓')] %}
             <div class="numpad" id="numpad-{{ i.0 }}" onclick="deposit_key('{{ i.0 }}');">{{ i.1 }}</div>
             {% endfor %}
+            <div id="transfer-userlist">
+                <div id="scroll-up" onclick="scrollUserlist(-130);">▲</div>
+                <ul id="transfer-userlist-list">
+                    {% for user in ((users if user != authuser) | sort(attribute='name')) %}
+                    <li onclick="set_transfer_user(this, {{ user.id }})">{{ user.name }}</li>
+                    {% endfor %}
+                </ul>
+                <div id="scroll-down" onclick="scrollUserlist(+130);">▼</div>
+            </div>
         </div>
     </div>
     <script src="/static/js/depositlist.js"></script>