Update app.py

app.py

@@ -19,7 +19,7 @@ end_date = st.date_input("Project End Date:", value=datetime.today() + timedelta
 
 num_activities = st.number_input("Number of Activities (Minimum 1):", min_value=1, value=5)
 
-activities =
+activities = [] # Corrected line 22: Placed outside the loop
 for i in range(num_activities):
     col1, col2 = st.columns(2)
     with col1:
@@ -28,7 +28,7 @@ for i in range(num_activities):
         activity_duration = st.number_input(f"Activity {i+1} Duration (days):", min_value=1, key=f"duration_{i}")
     activities.append({"Task": activity_name, "Duration": activity_duration})
 
-if st.button("Create Gantt Chart"): # The button is now correctly placed
+if st.button("Create Gantt Chart"):
     if not project_name:
         st.error("Please enter a project name.")
     elif any(not activity["Task"] for activity in activities):
@@ -43,4 +43,28 @@ if st.button("Create Gantt Chart"): # The button is now correctly placed
 
             for i in range(len(df)):
                 if i > 0:
-                    df.loc[i, 'Start'] = df.
+                    df.loc[i, 'Start'] = df.loc[i - 1, 'Finish']
+                df.loc[i, 'Finish'] = df.loc[i, 'Start'] + pd.to_timedelta(df.loc[i, 'Duration'], unit='D')
+
+            df['Start_str'] = df['Start'].dt.strftime('%Y-%m-%d')
+            df['Finish_str'] = df['Finish'].dt.strftime('%Y-%m-%d')
+
+            data = []
+            for _, row in df.iterrows():
+                data.append(dict(Task=row['Task'], Start=row['Start_str'], Finish=row['Finish_str']))
+
+            fig = ff.create_gantt(data, colors=[generate_random_color() for _ in range(len(df))],
+                                  index_col='Task', show_colorbar=False, group_tasks=True, bar_width=0.4,
+                                  showgrid_x=True, showgrid_y=True)
+
+            fig.update_layout(title_text=f"Gantt Chart for: {project_name}", title_x=0.5,
+                              margin=dict(l=20, r=20, t=60, b=20),
+                              xaxis=dict(range=[start_date, end_date]),
+                              height=600)
+
+            fig.update_yaxes(autorange="reversed")
+
+            st.plotly_chart(fig, use_container_width=True)
+
+        except Exception as e:
+            st.error(f"An error occurred during chart creation: {e}")