Add required field validation for invoice creation

VERSION

@@ -1 +1 @@
-0.0.7
+0.0.8

backend/app.py

@@ -12,7 +12,7 @@ app = Flask(
 def index():
     return """
     <h1>OTB Billing</h1>
-    <p>Version 0.0.7</p>
+    <p>Version 0.0.8</p>
     <p><a href="/clients">Clients</a></p>
     <p><a href="/services">Services</a></p>
     <p><a href="/invoices">Invoices</a></p>
@@ -44,25 +44,20 @@ def clients():
 def services():
     conn = get_db_connection()
     cursor = conn.cursor(dictionary=True)
-
     cursor.execute("""
         SELECT s.*, c.client_code, c.company_name
         FROM services s
         JOIN clients c ON s.client_id = c.id
         ORDER BY s.id DESC
     """)
-
     services = cursor.fetchall()
     conn.close()
-
     return render_template("services/list.html", services=services)
 
 @app.route("/invoices")
 def invoices():
-
     conn = get_db_connection()
     cursor = conn.cursor(dictionary=True)
-
     cursor.execute("""
         SELECT
             i.*,
@@ -72,35 +67,85 @@ def invoices():
         JOIN clients c ON i.client_id = c.id
         ORDER BY i.id DESC
     """)
-
     invoices = cursor.fetchall()
     conn.close()
-
     return render_template("invoices/list.html", invoices=invoices)
 
-@app.route("/invoices/new", methods=["GET","POST"])
+@app.route("/invoices/new", methods=["GET", "POST"])
 def new_invoice():
-
     conn = get_db_connection()
     cursor = conn.cursor(dictionary=True)
 
     if request.method == "POST":
+        client_id = request.form.get("client_id", "").strip()
+        service_id = request.form.get("service_id", "").strip()
+        currency_code = request.form.get("currency_code", "").strip()
+        total_amount = request.form.get("total_amount", "").strip()
+        due_at = request.form.get("due_at", "").strip()
+        notes = request.form.get("notes", "").strip()
+
+        errors = []
+
+        if not client_id:
+            errors.append("Client is required.")
+        if not service_id:
+            errors.append("Service is required.")
+        if not currency_code:
+            errors.append("Currency is required.")
+        if not total_amount:
+            errors.append("Total amount is required.")
+        if not due_at:
+            errors.append("Due date is required.")
+
+        if not errors:
+            try:
+                amount_value = float(total_amount)
+                if amount_value <= 0:
+                    errors.append("Total amount must be greater than zero.")
+            except ValueError:
+                errors.append("Total amount must be a valid number.")
+
+        if errors:
+            cursor.execute("""
+                SELECT id, client_code, company_name
+                FROM clients
+                ORDER BY company_name
+            """)
+            clients = cursor.fetchall()
 
-        client_id = request.form["client_id"]
-        service_id = request.form["service_id"]
-        currency_code = request.form["currency_code"]
-        total_amount = request.form["total_amount"]
-        due_at = request.form["due_at"]
-        notes = request.form["notes"]
+            cursor.execute("""
+                SELECT id, service_code, service_name
+                FROM services
+                ORDER BY service_name
+            """)
+            services = cursor.fetchall()
 
-        cursor.execute("SELECT MAX(id) as last_id FROM invoices")
+            conn.close()
+
+            form_data = {
+                "client_id": client_id,
+                "service_id": service_id,
+                "currency_code": currency_code,
+                "total_amount": total_amount,
+                "due_at": due_at,
+                "notes": notes,
+            }
+
+            return render_template(
+                "invoices/new.html",
+                clients=clients,
+                services=services,
+                errors=errors,
+                form_data=form_data,
+            )
+
+        cursor.execute("SELECT MAX(id) AS last_id FROM invoices")
         result = cursor.fetchone()
 
         number = (result["last_id"] or 0) + 1
         invoice_number = f"INV-{number:04d}"
 
         insert = conn.cursor()
-
         insert.execute("""
             INSERT INTO invoices
             (
@@ -115,9 +160,8 @@ def new_invoice():
                 status,
                 notes
             )
-            VALUES (%s,%s,%s,%s,%s,%s,NOW(),%s,'pending',%s)
-        """,
-        (
+            VALUES (%s, %s, %s, %s, %s, %s, NOW(), %s, 'pending', %s)
+        """, (
             client_id,
             service_id,
             invoice_number,
@@ -149,8 +193,13 @@ def new_invoice():
 
     conn.close()
 
-    return render_template("invoices/new.html", clients=clients, services=services)
-
+    return render_template(
+        "invoices/new.html",
+        clients=clients,
+        services=services,
+        errors=[],
+        form_data={},
+    )
 
 if __name__ == "__main__":
     app.run(host="0.0.0.0", port=5050)

templates/invoices/new.html

@@ -8,49 +8,66 @@
 
 <h1>Create Invoice</h1>
 
+{% if errors %}
+<div style="border:1px solid red; padding:10px; margin-bottom:15px;">
+    <strong>Please fix the following:</strong>
+    <ul>
+        {% for error in errors %}
+        <li>{{ error }}</li>
+        {% endfor %}
+    </ul>
+</div>
+{% endif %}
+
 <form method="post">
 
 <p>
-Client<br>
-<select name="client_id">
-{% for c in clients %}
-<option value="{{ c.id }}">{{ c.client_code }} - {{ c.company_name }}</option>
-{% endfor %}
+Client *<br>
+<select name="client_id" required>
+    <option value="">Select client</option>
+    {% for c in clients %}
+    <option value="{{ c.id }}" {% if form_data.get('client_id') == (c.id|string) %}selected{% endif %}>
+        {{ c.client_code }} - {{ c.company_name }}
+    </option>
+    {% endfor %}
 </select>
 </p>
 
 <p>
-Service<br>
-<select name="service_id">
-{% for s in services %}
-<option value="{{ s.id }}">{{ s.service_code }} - {{ s.service_name }}</option>
-{% endfor %}
+Service *<br>
+<select name="service_id" required>
+    <option value="">Select service</option>
+    {% for s in services %}
+    <option value="{{ s.id }}" {% if form_data.get('service_id') == (s.id|string) %}selected{% endif %}>
+        {{ s.service_code }} - {{ s.service_name }}
+    </option>
+    {% endfor %}
 </select>
 </p>
 
 <p>
-Currency<br>
-<select name="currency_code">
-<option value="CAD">CAD</option>
-<option value="ETHO">ETHO</option>
-<option value="EGAZ">EGAZ</option>
-<option value="ALT">ALT</option>
+Currency *<br>
+<select name="currency_code" required>
+    <option value="CAD" {% if form_data.get('currency_code', 'CAD') == 'CAD' %}selected{% endif %}>CAD</option>
+    <option value="ETHO" {% if form_data.get('currency_code') == 'ETHO' %}selected{% endif %}>ETHO</option>
+    <option value="EGAZ" {% if form_data.get('currency_code') == 'EGAZ' %}selected{% endif %}>EGAZ</option>
+    <option value="ALT" {% if form_data.get('currency_code') == 'ALT' %}selected{% endif %}>ALT</option>
 </select>
 </p>
 
 <p>
-Total Amount<br>
-<input type="number" step="0.00000001" name="total_amount">
+Total Amount *<br>
+<input type="number" step="0.00000001" min="0.00000001" name="total_amount" value="{{ form_data.get('total_amount', '') }}" required>
 </p>
 
 <p>
-Due Date<br>
-<input type="date" name="due_at">
+Due Date *<br>
+<input type="date" name="due_at" value="{{ form_data.get('due_at', '') }}" required>
 </p>
 
 <p>
 Notes<br>
-<textarea name="notes"></textarea>
+<textarea name="notes">{{ form_data.get('notes', '') }}</textarea>
 </p>
 
 <p>