feat: Remember generated invoice number

- Added `invoice_file` attribute to store the filename where the invoice number is persisted.
- Implemented `load_invoice_number` to read the last invoice number from the file on app startup. If the file doesn't exist or contains an invalid number, it defaults to 1.
- Implemented `save_invoice_number` to persist the incremented invoice number to the file after generating a PDF.
- Modified `export_to_pdf` to increment and save the invoice number after successful PDF generation.

time_logix.py

@@ -11,6 +11,7 @@ from reportlab.platypus import Table, TableStyle, Paragraph
 from reportlab.lib.styles import getSampleStyleSheet
 from reportlab.lib.units import inch
 import sys
+import os
 
 
 class TimeLogix:
@@ -28,112 +29,201 @@ class TimeLogix:
 
         # --- App Data ---
         self.project_file = "projects.txt"
+        self.invoice_file = "invoice_number.txt"  # File to store invoice number
         self.projects = self.load_projects()
         self.is_running = False
         self.start_time = None
         self.elapsed_time = 0
         self.timer_id = None
         self.log_entries = []
-        self.invoice_number = 1
+        self.invoice_number = self.load_invoice_number()  # Load invoice number
         self.company_name = "Your Company Name"
         self.company_address = "123 Main St, Anytown, USA"
         self.client_name = "Client Name"
         self.client_address = "Client Address"
         self.hourly_rate = 60.00
+        self.csv_file = "working_sessions.csv"
 
         # --- Scrollable Frame ---
-        self.scrollable_frame = ctk.CTkScrollableFrame(self.root, width=450, height=600) # Consider making height adaptable
+        self.scrollable_frame = ctk.CTkScrollableFrame(
+            self.root, width=450, height=600
+        )  # Consider making height adaptable
         self.scrollable_frame.pack(fill="both", expand=True, padx=10, pady=10)
 
         # --- UI Elements ---
-        self.task_label = ctk.CTkLabel(self.scrollable_frame, text="Task Description:", font=(self.font_family, self.font_size))
+        self.task_label = ctk.CTkLabel(
+            self.scrollable_frame,
+            text="Task Description:",
+            font=(self.font_family, self.font_size),
+        )
         self.task_label.pack(pady=(10, 2))
 
         self.task_entry = ctk.CTkEntry(self.scrollable_frame, width=250)
         self.task_entry.pack(pady=(2, 10))
 
-        self.project_label = ctk.CTkLabel(self.scrollable_frame, text="Project:", font=(self.font_family, self.font_size))
+        self.project_label = ctk.CTkLabel(
+            self.scrollable_frame,
+            text="Project:",
+            font=(self.font_family, self.font_size),
+        )
         self.project_label.pack(pady=(10, 2))
 
-        self.project_combo = ctk.CTkComboBox(self.scrollable_frame, values=self.projects, width=250)
+        self.project_combo = ctk.CTkComboBox(
+            self.scrollable_frame, values=self.projects, width=250
+        )
         self.project_combo.pack(pady=(2, 10))
         if self.projects:
             self.project_combo.set(self.projects[0])
 
-        self.time_label = ctk.CTkLabel(self.scrollable_frame, text="00:00:00", font=(self.font_family, 36))
+        self.time_label = ctk.CTkLabel(
+            self.scrollable_frame, text="00:00:00", font=(self.font_family, 36)
+        )
         self.time_label.pack(pady=(15, 20))
 
-        self.start_stop_button = ctk.CTkButton(self.scrollable_frame, text="Start", command=self.toggle_timer, corner_radius=8)
+        self.start_stop_button = ctk.CTkButton(
+            self.scrollable_frame,
+            text="Start",
+            command=self.toggle_timer,
+            corner_radius=8,
+        )
         self.start_stop_button.pack(pady=(5, 20))
 
-        self.log_label = ctk.CTkLabel(self.scrollable_frame, text="Log Entries:", font=(self.font_family, self.font_size))
+        self.log_label = ctk.CTkLabel(
+            self.scrollable_frame,
+            text="Log Entries:",
+            font=(self.font_family, self.font_size),
+        )
         self.log_label.pack(pady=(10, 2))
 
-        self.log_text = ctk.CTkTextbox(self.scrollable_frame, width=400, height=100, font=(self.font_family, self.font_size))
+        self.log_text = ctk.CTkTextbox(
-        self.log_text.pack(pady=5, padx=10, fill='both', expand=True)
+            self.scrollable_frame,
+            width=400,
+            height=100,
+            font=(self.font_family, self.font_size),
+        )
+        self.log_text.pack(pady=5, padx=10, fill="both", expand=True)
 
-        self.new_project_label = ctk.CTkLabel(self.scrollable_frame, text="New Project:", font=(self.font_family, self.font_size))
+        self.new_project_label = ctk.CTkLabel(
+            self.scrollable_frame,
+            text="New Project:",
+            font=(self.font_family, self.font_size),
+        )
         self.new_project_label.pack(pady=(10, 2))
 
         self.new_project_entry = ctk.CTkEntry(self.scrollable_frame, width=250)
         self.new_project_entry.pack(pady=(2, 10))
 
-        self.add_project_button = ctk.CTkButton(self.scrollable_frame, text="Add Project", command=self.add_project, corner_radius=8)
+        self.add_project_button = ctk.CTkButton(
+            self.scrollable_frame,
+            text="Add Project",
+            command=self.add_project,
+            corner_radius=8,
+        )
         self.add_project_button.pack(pady=(5, 15))
 
         # --- Button Frame ---
         button_frame = ctk.CTkFrame(self.scrollable_frame)
         button_frame.pack(pady=(10, 15))
 
-        self.export_csv_button = ctk.CTkButton(button_frame, text="Export to CSV", command=self.export_to_csv, corner_radius=8)
+        self.export_csv_button = ctk.CTkButton(
-        self.export_csv_button.pack(side="left", padx=5, pady=5)  # Using side="left" for horizontal layout
+            button_frame,
+            text="Export to CSV",
+            command=self.export_to_csv,
+            corner_radius=8,
+        )
+        self.export_csv_button.pack(
+            side="left", padx=5, pady=5
+        )  # Using side="left" for horizontal layout
 
-        self.export_pdf_button = ctk.CTkButton(button_frame, text="Export to PDF", command=self.export_to_pdf, corner_radius=8)
+        self.export_pdf_button = ctk.CTkButton(
+            button_frame,
+            text="Export to PDF",
+            command=self.export_to_pdf,
+            corner_radius=8,
+        )
         self.export_pdf_button.pack(side="left", padx=5, pady=5)
 
-        self.exit_button = ctk.CTkButton(button_frame, text="Exit", command=self.exit_app, corner_radius=8)
+        self.exit_button = ctk.CTkButton(
+            button_frame, text="Exit", command=self.exit_app, corner_radius=8
+        )
         self.exit_button.pack(side="left", padx=5, pady=5)
 
-        self.total_time_button = ctk.CTkButton(self.scrollable_frame, text="Calculate Total Time", command=self.calculate_total_time, corner_radius=8)
+        self.total_time_button = ctk.CTkButton(
+            self.scrollable_frame,
+            text="Calculate Total Time",
+            command=self.calculate_total_time,
+            corner_radius=8,
+        )
         self.total_time_button.pack(pady=(5, 15))
 
-        self.total_time_label = ctk.CTkLabel(self.scrollable_frame, text="Total Time: 00:00:00", font=(self.font_family, self.font_size))
+        self.total_time_label = ctk.CTkLabel(
+            self.scrollable_frame,
+            text="Total Time: 00:00:00",
+            font=(self.font_family, self.font_size),
+        )
         self.total_time_label.pack(pady=(5, 15))
 
         # --- Settings UI ---
-        self.company_name_label = ctk.CTkLabel(self.scrollable_frame, text="Company Name:", font=(self.font_family, self.font_size))
+        self.company_name_label = ctk.CTkLabel(
+            self.scrollable_frame,
+            text="Company Name:",
+            font=(self.font_family, self.font_size),
+        )
         self.company_name_label.pack(pady=(10, 2))
 
         self.company_name_entry = ctk.CTkEntry(self.scrollable_frame, width=250)
         self.company_name_entry.pack(pady=(2, 10))
 
-        self.company_address_label = ctk.CTkLabel(self.scrollable_frame, text="Company Address:", font=(self.font_family, self.font_size))
+        self.company_address_label = ctk.CTkLabel(
+            self.scrollable_frame,
+            text="Company Address:",
+            font=(self.font_family, self.font_size),
+        )
         self.company_address_label.pack(pady=(10, 2))
 
         self.company_address_entry = ctk.CTkEntry(self.scrollable_frame, width=250)
         self.company_address_entry.pack(pady=(2, 10))
 
-        self.client_name_label = ctk.CTkLabel(self.scrollable_frame, text="Client Name:", font=(self.font_family, self.font_size))
+        self.client_name_label = ctk.CTkLabel(
+            self.scrollable_frame,
+            text="Client Name:",
+            font=(self.font_family, self.font_size),
+        )
         self.client_name_label.pack(pady=(10, 2))
 
         self.client_name_entry = ctk.CTkEntry(self.scrollable_frame, width=250)
         self.client_name_entry.pack(pady=(2, 10))
 
-        self.client_address_label = ctk.CTkLabel(self.scrollable_frame, text="Client Address:", font=(self.font_family, self.font_size))
+        self.client_address_label = ctk.CTkLabel(
+            self.scrollable_frame,
+            text="Client Address:",
+            font=(self.font_family, self.font_size),
+        )
         self.client_address_label.pack(pady=(10, 2))
 
         self.client_address_entry = ctk.CTkEntry(self.scrollable_frame, width=250)
         self.client_address_entry.pack(pady=(2, 10))
 
-        self.hourly_rate_label = ctk.CTkLabel(self.scrollable_frame, text="Hourly Rate:", font=(self.font_family, self.font_size))
+        self.hourly_rate_label = ctk.CTkLabel(
+            self.scrollable_frame,
+            text="Hourly Rate:",
+            font=(self.font_family, self.font_size),
+        )
         self.hourly_rate_label.pack(pady=(10, 2))
 
         self.hourly_rate_entry = ctk.CTkEntry(self.scrollable_frame, width=100)
         self.hourly_rate_entry.pack(pady=(2, 10))
 
-        self.update_settings_button = ctk.CTkButton(self.scrollable_frame, text="Update Settings", command=self.update_settings, corner_radius=8)
+        self.update_settings_button = ctk.CTkButton(
+            self.scrollable_frame,
+            text="Update Settings",
+            command=self.update_settings,
+            corner_radius=8,
+        )
         self.update_settings_button.pack(pady=(15, 20))
 
+        self.load_log_entries()
+
     def load_projects(self):
         try:
             with open(self.project_file, "r") as f:
@@ -150,6 +240,23 @@ class TimeLogix:
         except Exception as e:
             print(f"Error saving projects: {e}")
 
+    def load_invoice_number(self):
+        try:
+            with open(self.invoice_file, "r") as f:
+                return int(f.read().strip())
+        except FileNotFoundError:
+            return 1
+        except ValueError:
+            print("Invalid invoice number in file, resetting to 1.")
+            return 1
+
+    def save_invoice_number(self):
+        try:
+            with open(self.invoice_file, "w") as f:
+                f.write(str(self.invoice_number))
+        except Exception as e:
+            print(f"Error saving invoice number: {e}")
+
     def add_project(self):
         new_project = self.new_project_entry.get().strip()
         if new_project and new_project not in self.projects:
@@ -229,12 +336,40 @@ class TimeLogix:
             self.log_text.insert(tk.END, f"Project: {entry['project']}\n")
             self.log_text.insert(tk.END, f"Start: {entry['start_time']}\n")
             self.log_text.insert(tk.END, f"End: {entry['end_time']}\n")
-            self.log_text.insert(tk.END, f"Duration: {entry['duration']} seconds\n")
+            self.log_text.insert(
+                tk.END, f"Duration: {entry['duration']} seconds\n"
+            )
             self.log_text.insert(tk.END, "-" * 20 + "\n")
 
+    def load_log_entries(self):
+        if os.path.exists(self.csv_file):
+            try:
+                with open(self.csv_file, "r") as csvfile:
+                    reader = csv.DictReader(csvfile)
+                    for row in reader:
+                        try:
+                            row["duration"] = float(row["duration"])
+                        except ValueError:
+                            # Try converting duration from hh:mm:ss format to seconds
+                            try:
+                                h, m, s = map(int, row["duration"].split(":"))
+                                row["duration"] = h * 3600 + m * 60 + s
+                            except ValueError:
+                                print(
+                                    f"Invalid duration format: {row['duration']}. "
+                                    "Skipping this entry."
+                                )
+                                continue  # Skip this entry if the format is invalid
+
+                        self.log_entries.append(row)
+                self.update_log_display()
+                print("Loaded log entries from CSV successfully!")
+            except Exception as e:
+                print(f"Error loading log entries from CSV: {e}")
+
     def export_to_csv(self):
         try:
-            with open("working_sessions.csv", "w", newline="") as csvfile:
+            with open(self.csv_file, "w", newline="") as csvfile:
                 fieldnames = ["task", "project", "start_time", "end_time", "duration"]
                 writer = csv.DictWriter(csvfile, fieldnames=fieldnames)
                 writer.writeheader()
@@ -266,11 +401,19 @@ class TimeLogix:
             c.drawString(4.5 * inch, 7.1 * inch, f"Date: {current_date}")
 
             # --- Client Info ---
+            bill_to_y = 6.5 * inch  # Starting y position for "Bill To:"
+            line_height = 0.2 * inch  # Height for each line of text
+
             c.setFont("Helvetica-Bold", 12)
-            c.drawString(inch, 6.5 * inch, "Bill To:")
+            c.drawString(inch, bill_to_y, "Bill To:")  # "Bill To:" label
+
             c.setFont("Helvetica", 10)
-            c.drawString(inch, 6.3 * inch, self.client_name)
+            c.drawString(
-            c.drawString(inch, 6.1 * inch, self.client_address)
+                inch, bill_to_y - line_height, self.client_name
+            )  # Client Name
+            c.drawString(
+                inch, bill_to_y - 2 * line_height, self.client_address
+            )  # Client Address
 
             # --- Table ---
             data = [["Task", "Project", "Hours", "Rate", "Total"]]
@@ -330,6 +473,7 @@ class TimeLogix:
             c.save()
             print(f"Exported to PDF successfully as {filename}!")
             self.invoice_number += 1
+            self.save_invoice_number()  # Save the updated invoice number
 
         except Exception as e:
             print(f"Error exporting to PDF: {e}")