"""Backup restore dialog - lists all backups and offers restore/delete actions."""

import tkinter as tk
from tkinter import messagebox


class BackupDialog(tk.Toplevel):
    """Modal dialog for browsing and restoring backups."""

    PAGE_SIZE = 50

    def __init__(self, parent, backup_manager, on_restore=None):
        super().__init__(parent)
        self.backup_manager = backup_manager
        self.on_restore = on_restore
        self._visible_count = self.PAGE_SIZE

        self.title("Backup Manager")
        self.geometry("520x520")
        self.minsize(400, 400)
        self.configure(bg="#2D2D3D")
        self.transient(parent)
        self.grab_set()

        self._build_ui()
        self._refresh()

    def _build_ui(self):
        header = tk.Frame(self, bg="#1E1E2E")
        header.pack(fill="x")
        tk.Label(header, text="Backups", bg="#1E1E2E", fg="white",
                 font=("Segoe UI", 12, "bold"), pady=10).pack(side="left", padx=14)

        info = tk.Label(self, text="Automatic backups are taken after changes are made.\n"
                        "Select a backup to restore or delete it.",
                        bg="#2D2D3D", fg="#AAAAAA", font=("Segoe UI", 9),
                        justify="left")
        info.pack(anchor="w", padx=14, pady=(8, 4))

        list_frame = tk.Frame(self, bg="#2D2D3D")
        list_frame.pack(fill="both", expand=True, padx=14, pady=(4, 8))

        header_row = tk.Frame(list_frame, bg="#1E1E2E")
        header_row.pack(fill="x")
        tk.Label(header_row, text="When", bg="#1E1E2E", fg="#888888",
                 font=("Segoe UI", 9, "bold"), anchor="w").pack(side="left", fill="x",
                                                                 expand=True, padx=(8, 4), pady=4)
        tk.Label(header_row, text="Size", bg="#1E1E2E", fg="#888888",
                 font=("Segoe UI", 9, "bold"), anchor="w",
                 width=10).pack(side="left", padx=4, pady=4)

        canvas_frame = tk.Frame(list_frame, bg="#1E1E2E")
        canvas_frame.pack(fill="both", expand=True)

        self._list_canvas = tk.Canvas(canvas_frame, bg="#1E1E2E", highlightthickness=0)
        scrollbar = tk.Scrollbar(canvas_frame, orient="vertical",
                                  command=self._list_canvas.yview)
        self._list_inner = tk.Frame(self._list_canvas, bg="#1E1E2E")

        self._list_inner.bind("<Configure>",
                              lambda e: self._list_canvas.configure(
                                  scrollregion=self._list_canvas.bbox("all")))
        self._list_canvas.create_window((0, 0), window=self._list_inner, anchor="nw", tags="inner")
        self._list_canvas.configure(yscrollcommand=scrollbar.set)
        self._list_canvas.bind("<Configure>",
                               lambda e: self._list_canvas.itemconfig("inner", width=e.width))
        self._list_canvas.bind_all("<MouseWheel>",
                                    lambda e: self._list_canvas.yview_scroll(
                                        -1 * (e.delta // 120), "units"))

        self._list_canvas.pack(side="left", fill="both", expand=True)
        scrollbar.pack(side="right", fill="y")

        footer = tk.Frame(self, bg="#1E1E2E")
        footer.pack(fill="x", side="bottom")

        self._status_label = tk.Label(footer, text="", bg="#1E1E2E", fg="#AAAAAA",
                                       font=("Segoe UI", 9))
        self._status_label.pack(side="left", padx=14, pady=10)

        tk.Button(footer, text="Close", command=self.destroy, bg="#3D3D5C", fg="white",
                  font=("Segoe UI", 9), relief="flat",
                  padx=14, pady=4).pack(side="right", padx=8, pady=8)

        tk.Button(footer, text="Create Backup Now", command=self._create_now,
                  bg="#4A4A6A", fg="white", font=("Segoe UI", 9), relief="flat",
                  padx=10, pady=4).pack(side="right", padx=4, pady=8)

    def _refresh(self):
        """Rebuild the backup list."""
        for widget in self._list_inner.winfo_children():
            widget.destroy()

        backups = self.backup_manager.list_backups()
        total_count = len(backups)

        if self._visible_count < self.PAGE_SIZE:
            self._visible_count = self.PAGE_SIZE
        shown = min(self._visible_count, total_count)

        if not backups:
            tk.Label(self._list_inner, text="No backups yet.",
                     bg="#1E1E2E", fg="#666666", font=("Segoe UI", 10, "italic"),
                     pady=20).pack()
        else:
            for i, info in enumerate(backups[:shown]):
                self._create_row(info, i)

            remaining = total_count - shown
            if remaining > 0:
                self._create_load_more_row(remaining)

        total = self.backup_manager.total_size_formatted()
        if total_count and shown < total_count:
            label = (f"Showing {shown} of {total_count} backup"
                     f"{'s' if total_count != 1 else ''}   •   {total} on disk")
        else:
            label = (f"{total_count} backup{'s' if total_count != 1 else ''}"
                     f"   •   {total} on disk")
        self._status_label.config(text=label)

    def _create_load_more_row(self, remaining):
        row = tk.Frame(self._list_inner, bg="#1E1E2E")
        row.pack(fill="x", pady=6)
        take = min(self.PAGE_SIZE, remaining)
        tk.Button(row, text=f"Load {take} more  ({remaining} remaining)",
                  command=self._load_more,
                  bg="#3D3D5C", fg="white", font=("Segoe UI", 9),
                  relief="flat", padx=14, pady=4).pack(pady=4)

    def _load_more(self):
        self._visible_count += self.PAGE_SIZE
        self._refresh()
        # Jump to the bottom so the newly-loaded rows are visible
        self._list_canvas.update_idletasks()
        self._list_canvas.yview_moveto(1.0)

    def _create_row(self, info, index):
        bg = "#222230" if index % 2 == 0 else "#1E1E2E"
        hover_bg = "#2A2A3A"

        row = tk.Frame(self._list_inner, bg=bg, cursor="hand2")
        row.pack(fill="x")

        ts_label = tk.Label(row, text=info.human_readable_time(),
                             bg=bg, fg="white", font=("Segoe UI", 10),
                             anchor="w", padx=8, pady=6)
        ts_label.pack(side="left", fill="x", expand=True)

        size_label = tk.Label(row, text=info.human_readable_size(),
                               bg=bg, fg="#AAAAAA", font=("Segoe UI", 9),
                               anchor="w", width=10, padx=4, pady=6)
        size_label.pack(side="left")

        del_btn = tk.Button(row, text="×", bg="#3D3D5C", fg="#FF7777",
                             font=("Segoe UI", 11, "bold"), relief="flat",
                             width=2,
                             command=lambda p=info.path: self._delete_one(p))
        del_btn.pack(side="right", padx=(4, 8), pady=3)

        restore_btn = tk.Button(row, text="Restore", bg="#27AE60", fg="white",
                                 font=("Segoe UI", 9), relief="flat",
                                 padx=10, pady=2,
                                 command=lambda p=info.path: self._restore_one(p))
        restore_btn.pack(side="right", padx=4, pady=3)

        for w in (row, ts_label, size_label):
            w.bind("<Enter>", lambda e, r=row: self._set_bg(r, hover_bg))
            w.bind("<Leave>", lambda e, r=row, b=bg: self._set_bg(r, b))

    def _set_bg(self, row, color):
        row.config(bg=color)
        for c in row.winfo_children():
            if isinstance(c, tk.Label):
                c.config(bg=color)

    def _delete_one(self, path):
        if not messagebox.askyesno("Delete Backup",
                                    f"Delete this backup?\n\n{path.name}\n\n"
                                    "This cannot be undone.",
                                    parent=self):
            return
        self.backup_manager.delete_backup(path)
        self._refresh()

    def _restore_one(self, path):
        if not messagebox.askyesno("Restore Backup",
                                    "Restoring will replace ALL current profiles,\n"
                                    "settings, and images with the backup's contents.\n\n"
                                    f"Restore from:\n{path.name}?\n\n"
                                    "A safety backup of the current state will be\n"
                                    "created automatically before restoring.",
                                    parent=self):
            return

        self.backup_manager.create_backup()  # safety snapshot so the user can undo

        if self.on_restore:
            ok = self.on_restore(path)
            if ok:
                messagebox.showinfo("Restore Complete",
                                     "Backup restored successfully.",
                                     parent=self)
                self.destroy()
            else:
                messagebox.showerror("Restore Failed",
                                      "Could not restore the backup.\n"
                                      "Check the console for details.",
                                      parent=self)
                self._refresh()

    def _create_now(self):
        path = self.backup_manager.create_backup()
        if path:
            self._refresh()
        else:
            messagebox.showerror("Backup Failed",
                                  "Could not create a backup.\n"
                                  "Check the console for details.",
                                  parent=self)