3. Flight Booker

.gitignore

@@ -1 +1,2 @@
-__pycache__
+__pycache__
+tests

3_Flight_Booker/README.md

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+**Gradio implementation of [Flight Booker](https://7guis.github.io/7guis/tasks/#flight):**
+
+<img src="assets/flight-booker.png" alt="Flight Booker with Gradio"/>

3_Flight_Booker/app.py

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+import gradio as gr
+from datetime import datetime
+
+def return_state(flight_type: str):
+    """Changes interactivity of the returning date Textbox depending on flight type."""
+    state = flight_type == "return flight"
+    return gr.Textbox.update(value="", interactive=state)
+
+def display_message(flight_type: str, start_date: str, return_date: str):
+    """If the book button is clicked, displays a message."""
+    if flight_type == "one-way flight":
+        message = f"You have booked a {flight_type} on {start_date}."
+    else:
+        message = f"You have booked a {flight_type} starting on {start_date} and returning on {return_date}."
+    return gr.TextArea.update(message, visible=True)
+
+def remove_message():
+    """Clears and removes message display."""
+    return gr.TextArea.update("", visible=False)
+
+def validate_date(date: str):
+    """Extracts date from string."""
+    valid = True
+    try:
+        date = datetime.strptime(date, "%d.%m.%Y")
+    except Exception:
+        valid = False
+    return date, valid
+
+def check_date(flight_type: str, start_date: str, return_date: str):
+    """If the date is updated, checks format, and updates button and warning."""
+    state, v2 = True, True
+
+    d1, v1 = validate_date(start_date)
+    if flight_type == "return flight":
+        d2, v2 = validate_date(return_date)
+        state = d1 <= d2 if v1 and v2 else False
+    else:
+        state = v1
+
+    return (
+        gr.Button.update(visible=state),
+        gr.HighlightedText.update(visible=not v1),
+        gr.HighlightedText.update(visible=not v2)
+    )
+
+
+TODAY = datetime.now().strftime("%d.%m.%Y")
+DATE_HINT = "dd.mm.yyyy"
+
+with gr.Blocks() as demo:
+    gr.Markdown(
+        """# Flight Booker
+        """
+    )
+    with gr.Column():
+        flight_type = gr.Dropdown(["one-way flight", "return flight"], value="one-way flight", show_label=False)
+        with gr.Row():
+
+            start_date = gr.Textbox(TODAY, max_lines=1, placeholder=DATE_HINT, show_label=False).style()
+            start_status = gr.HighlightedText([(DATE_HINT, "X")], show_label=False, visible=False).style(color_map={"X": "red"})
+
+        with gr.Row():
+            return_date = gr.Textbox("", max_lines=1, placeholder=DATE_HINT, show_label=False, interactive=False)
+            return_status = gr.HighlightedText([(DATE_HINT, "X")], show_label=False, visible=False).style(color_map={"X": "red"})
+        button = gr.Button("Book")
+        message = gr.Textbox(max_lines=1, visible=False, interactive=False, show_label=False)
+
+        flight_type.change(return_state, flight_type, return_date)
+        flight_type.change(check_date, [flight_type, start_date, return_date], [button, start_status, return_status])
+        flight_type.change(remove_message, [], message)
+
+        start_date.change(check_date, [flight_type, start_date, return_date], [button, start_status, return_status])
+        start_date.change(remove_message, [], message)
+
+        return_date.change(check_date, [flight_type, start_date, return_date], [button, start_status, return_status])
+        return_date.change(remove_message, [], message)
+
+        button.click(display_message, [flight_type, start_date, return_date], message)
+
+if __name__ == "__main__":
+    demo.launch()