gui.py

import tkinter as tk
from tkinter import filedialog, messagebox, Canvas, Frame
from pdf2image import convert_from_path
from PIL import ImageTk

# Import the splitting logic from our separate module.
from pdf_splitter_logic import split_pdf_file

class PDFSplitterApp:
    def __init__(self, root):
        self.root = root
        self.root.title("PDF Splitter with Preview")
        self.root.geometry("1000x700")

        self.pdf_path_var = tk.StringVar()
        self.split_points = []  # List of page numbers indicating the start of a new section.
        self.thumbnails = []    # Store thumbnail images (Tkinter PhotoImage)
        self.images = []        # Store PIL image references to avoid garbage collection
        self.columns = 4        # Number of columns in grid

        self.setup_ui()

    def setup_ui(self):
        """Create the main GUI elements."""
        tk.Label(self.root, text="Select PDF File:").pack(pady=5)
        tk.Entry(self.root, textvariable=self.pdf_path_var, width=60, state="readonly").pack()
        tk.Button(self.root, text="Browse", command=self.select_pdf).pack(pady=5)

        # Scrollable frame for thumbnails
        self.preview_frame = Frame(self.root)
        self.preview_frame.pack(pady=10, fill=tk.BOTH, expand=True)

        self.canvas = Canvas(self.preview_frame)
        self.scroll_y = tk.Scrollbar(self.preview_frame, orient="vertical", command=self.canvas.yview)
        self.scroll_y.pack(side="right", fill="y")

        self.scrollable_frame = Frame(self.canvas)
        self.scrollable_frame.bind(
            "<Configure>",
            lambda e: self.canvas.configure(scrollregion=self.canvas.bbox("all"))
        )
        self.canvas.create_window((0, 0), window=self.scrollable_frame, anchor="nw")
        self.canvas.configure(yscrollcommand=self.scroll_y.set)
        self.canvas.pack(side="left", fill=tk.BOTH, expand=True)

        # Enable mouse wheel scrolling
        self.canvas.bind_all("<MouseWheel>", self.on_mouse_wheel)   # Windows
        self.canvas.bind_all("<Button-4>", self.on_mouse_wheel)     # macOS/Linux scroll up
        self.canvas.bind_all("<Button-5>", self.on_mouse_wheel)     # macOS/Linux scroll down

        tk.Button(self.root, text="Split PDF", command=self.split_pdf).pack(pady=10)

    def on_mouse_wheel(self, event):
        """Enable scrolling with the mouse wheel."""
        if event.num == 5 or event.delta < 0:
            self.canvas.yview_scroll(1, "units")
        elif event.num == 4 or event.delta > 0:
            self.canvas.yview_scroll(-1, "units")

    def select_pdf(self):
        """Open a file dialog to select a PDF file."""
        file_path = filedialog.askopenfilename(filetypes=[("PDF Files", "*.pdf")])
        if file_path:
            self.pdf_path_var.set(file_path)
            self.load_preview()

    def load_preview(self):
        """Generate and display page thumbnails with clickable split markers."""
        pdf_path = self.pdf_path_var.get()
        if not pdf_path:
            return

        # Clear previous content.
        for widget in self.scrollable_frame.winfo_children():
            widget.destroy()
        self.split_points.clear()
        self.thumbnails.clear()
        self.images.clear()

        # Convert PDF pages to thumbnail images.
        images = convert_from_path(pdf_path, size=(180, 240))
        num_pages = len(images)
        rows = (num_pages // self.columns) + (1 if num_pages % self.columns else 0)

        for row in range(rows):
            row_frame = Frame(self.scrollable_frame)
            row_frame.pack(fill="x", pady=5)

            for col in range(self.columns):
                page_idx = row * self.columns + col
                if page_idx >= num_pages:
                    break

                img = images[page_idx]
                thumbnail = ImageTk.PhotoImage(img)
                self.thumbnails.append(thumbnail)
                self.images.append(img)  # Avoid garbage collection.

                # Create a container for each page preview.
                page_container = Frame(row_frame, borderwidth=2, relief="solid")
                page_container.pack(side="left", padx=5)

                img_label = tk.Label(page_container, image=thumbnail)
                img_label.pack()

                page_num_label = tk.Label(page_container, text=f"Page {page_idx + 1}")
                page_num_label.pack()

                # Add a vertical split marker after every column except the last in the row.
                if col < self.columns - 1 and page_idx + 1 < num_pages:
                    # The marker indicates that the next section starts at page (page_idx + 2)
                    separator = Canvas(row_frame, width=5, height=250, bg="gray")
                    separator.pack(side="left", padx=2)
                    separator.bind("<Button-1>", lambda e, page=page_idx + 2: self.toggle_split_point(page, e))

            # Add a vertical split marker at the end of each row if it is not the last page.
            last_page_in_row = row * self.columns + (self.columns - 1)
            if last_page_in_row < num_pages - 1:
                end_separator = Canvas(row_frame, width=5, height=250, bg="gray")
                end_separator.pack(side="left", padx=2)
                end_separator.bind("<Button-1>", lambda e, page=last_page_in_row + 2: self.toggle_split_point(page, e))

        # Update the canvas scroll region.
        self.canvas.configure(scrollregion=self.canvas.bbox("all"))

    def toggle_split_point(self, page, event):
        """
        Toggle the split point when a marker is clicked.
        The parameter 'page' indicates the first page of the new part.
        For example, clicking a marker that gives page 4 will result in:
            - Part 1: pages 1–3
            - Part 2: starting at page 4
        """
        if page in self.split_points:
            self.split_points.remove(page)
            event.widget.config(bg="gray")
        else:
            self.split_points.append(page)
            event.widget.config(bg="red")
        self.split_points.sort()

    def split_pdf(self):
        """Call the splitting logic to split the PDF file."""
        pdf_path = self.pdf_path_var.get()
        if not pdf_path or not self.split_points:
            messagebox.showerror("Error", "Please select a PDF file and at least one split point.")
            return

        try:
            # Call the splitting logic (from pdf_splitter_logic.py)
            output_dir = split_pdf_file(pdf_path, self.split_points)
            messagebox.showinfo("Success", f"PDF split successfully!\nFiles saved in: {output_dir}")
        except Exception as e:
            messagebox.showerror("Error", str(e))

# Run the app.
if __name__ == "__main__":
    root = tk.Tk()
    app = PDFSplitterApp(root)
    root.mainloop()