#!/usr/bin/env python3
import atexit
import curses
import os
import pickle
import queue
import re
import signal
import socket
import sys
import threading
import time


class RPEditor:
    def __init__(self, filename=None, auto_save=False, timeout=30):
        """
        Initialize RPEditor with enhanced robustness features.

        Args:
            filename: File to edit
            auto_save: Enable auto-save on exit
            timeout: Command timeout in seconds
        """
        self.filename = filename
        self.lines = [""]
        self.cursor_y = 0
        self.cursor_x = 0
        self.mode = "normal"
        self.command = ""
        self.stdscr = None
        self.running = False
        self.thread = None
        self.socket_thread = None
        self.prev_key = None
        self.clipboard = ""
        self.undo_stack = []
        self.redo_stack = []
        self.selection_start = None
        self.selection_end = None
        self.max_undo = 100
        self.lock = threading.RLock()
        self.command_queue = queue.Queue()
        self.auto_save = auto_save
        self.timeout = timeout
        self._cleanup_registered = False
        self._original_terminal_state = None
        self._exception_occurred = False

        # Create socket pair with error handling
        try:
            self.client_sock, self.server_sock = socket.socketpair()
            self.client_sock.settimeout(self.timeout)
            self.server_sock.settimeout(self.timeout)
        except Exception as e:
            self._cleanup()
            raise RuntimeError(f"Failed to create socket pair: {e}")

        # Register cleanup handlers
        self._register_cleanup()

        if filename:
            self.load_file()

    def _register_cleanup(self):
        """Register cleanup handlers for proper shutdown."""
        if not self._cleanup_registered:
            atexit.register(self._cleanup)
            signal.signal(signal.SIGINT, self._signal_handler)
            signal.signal(signal.SIGTERM, self._signal_handler)
            self._cleanup_registered = True

    def _signal_handler(self, signum, frame):
        """Handle signals for clean shutdown."""
        self._cleanup()
        sys.exit(0)

    def _cleanup(self):
        """Comprehensive cleanup of all resources."""
        try:
            # Stop the editor
            self.running = False

            # Save if auto-save is enabled
            if self.auto_save and self.filename and not self._exception_occurred:
                try:
                    self._save_file()
                except:
                    pass

            # Clean up curses
            if self.stdscr:
                try:
                    self.stdscr.keypad(False)
                    curses.nocbreak()
                    curses.echo()
                    curses.curs_set(1)
                except:
                    pass
                finally:
                    try:
                        curses.endwin()
                    except:
                        pass

            # Clear screen after curses cleanup
            try:
                os.system("clear" if os.name != "nt" else "cls")
            except:
                pass

            # Close sockets
            for sock in [self.client_sock, self.server_sock]:
                if sock:
                    try:
                        sock.close()
                    except:
                        pass

            # Wait for threads to finish
            for thread in [self.thread, self.socket_thread]:
                if thread and thread.is_alive():
                    thread.join(timeout=1)

        except:
            pass

    def load_file(self):
        """Load file with enhanced error handling."""
        try:
            if os.path.exists(self.filename):
                with open(self.filename, encoding="utf-8", errors="replace") as f:
                    content = f.read()
                    self.lines = content.splitlines() if content else [""]
            else:
                self.lines = [""]
        except Exception:
            self.lines = [""]
            # Don't raise, just use empty content

    def _save_file(self):
        """Save file with enhanced error handling and backup."""
        with self.lock:
            if not self.filename:
                return False

            try:
                # Create backup if file exists
                if os.path.exists(self.filename):
                    backup_name = f"{self.filename}.bak"
                    try:
                        with open(self.filename, encoding="utf-8") as f:
                            backup_content = f.read()
                        with open(backup_name, "w", encoding="utf-8") as f:
                            f.write(backup_content)
                    except:
                        pass  # Backup failed, but continue with save

                # Save the file
                with open(self.filename, "w", encoding="utf-8") as f:
                    f.write("\n".join(self.lines))
                return True
            except Exception:
                return False

    def save_file(self):
        """Thread-safe save file command."""
        if not self.running:
            return self._save_file()
        try:
            self.client_sock.send(pickle.dumps({"command": "save_file"}))
        except:
            return self._save_file()  # Fallback to direct save

    def start(self):
        """Start the editor with enhanced error handling."""
        if self.running:
            return False

        try:
            self.running = True
            self.socket_thread = threading.Thread(target=self.socket_listener, daemon=True)
            self.socket_thread.start()
            self.thread = threading.Thread(target=self.run, daemon=True)
            self.thread.start()
            return True
        except Exception as e:
            self.running = False
            self._cleanup()
            raise RuntimeError(f"Failed to start editor: {e}")

    def stop(self):
        """Stop the editor with proper cleanup."""
        try:
            if self.client_sock:
                self.client_sock.send(pickle.dumps({"command": "stop"}))
        except:
            pass

        self.running = False
        time.sleep(0.1)  # Give threads time to finish
        self._cleanup()

    def run(self):
        """Run the main editor loop with exception handling."""
        try:
            curses.wrapper(self.main_loop)
        except Exception:
            self._exception_occurred = True
            self._cleanup()

    def main_loop(self, stdscr):
        """Main editor loop with enhanced error recovery."""
        self.stdscr = stdscr

        try:
            # Configure curses
            curses.curs_set(1)
            self.stdscr.keypad(True)
            self.stdscr.timeout(100)  # Non-blocking with timeout

            while self.running:
                try:
                    # Process queued commands
                    while True:
                        try:
                            command = self.command_queue.get_nowait()
                            with self.lock:
                                self.execute_command(command)
                        except queue.Empty:
                            break

                    # Draw screen
                    with self.lock:
                        self.draw()

                    # Handle input
                    try:
                        key = self.stdscr.getch()
                        if key != -1:  # -1 means timeout/no input
                            with self.lock:
                                self.handle_key(key)
                    except curses.error:
                        pass  # Ignore curses errors

                except Exception:
                    # Log error but continue running
                    pass

        except Exception:
            self._exception_occurred = True
        finally:
            self._cleanup()

    def draw(self):
        """Draw the editor screen with error handling."""
        try:
            self.stdscr.clear()
            height, width = self.stdscr.getmaxyx()

            # Draw lines
            for i, line in enumerate(self.lines):
                if i >= height - 1:
                    break
                try:
                    # Handle long lines and special characters
                    display_line = line[: width - 1] if len(line) >= width else line
                    self.stdscr.addstr(i, 0, display_line)
                except curses.error:
                    pass  # Skip lines that can't be displayed

            # Draw status line
            status = f"{self.mode.upper()} | {self.filename or 'untitled'} | {self.cursor_y+1}:{self.cursor_x+1}"
            if self.mode == "command":
                status = self.command[: width - 1]

            try:
                self.stdscr.addstr(height - 1, 0, status[: width - 1])
            except curses.error:
                pass

            # Position cursor
            cursor_x = min(self.cursor_x, width - 1)
            cursor_y = min(self.cursor_y, height - 2)
            try:
                self.stdscr.move(cursor_y, cursor_x)
            except curses.error:
                pass

            self.stdscr.refresh()
        except Exception:
            pass  # Continue even if draw fails

    def handle_key(self, key):
        """Handle keyboard input with error recovery."""
        try:
            if self.mode == "normal":
                self.handle_normal(key)
            elif self.mode == "insert":
                self.handle_insert(key)
            elif self.mode == "command":
                self.handle_command(key)
        except Exception:
            pass  # Continue on error

    def handle_normal(self, key):
        """Handle normal mode keys."""
        try:
            if key == ord("h") or key == curses.KEY_LEFT:
                self.move_cursor(0, -1)
            elif key == ord("j") or key == curses.KEY_DOWN:
                self.move_cursor(1, 0)
            elif key == ord("k") or key == curses.KEY_UP:
                self.move_cursor(-1, 0)
            elif key == ord("l") or key == curses.KEY_RIGHT:
                self.move_cursor(0, 1)
            elif key == ord("i"):
                self.mode = "insert"
            elif key == ord(":"):
                self.mode = "command"
                self.command = ":"
            elif key == ord("x"):
                self._delete_char()
            elif key == ord("a"):
                self.cursor_x = min(self.cursor_x + 1, len(self.lines[self.cursor_y]))
                self.mode = "insert"
            elif key == ord("A"):
                self.cursor_x = len(self.lines[self.cursor_y])
                self.mode = "insert"
            elif key == ord("o"):
                self._insert_line(self.cursor_y + 1, "")
                self.cursor_y += 1
                self.cursor_x = 0
                self.mode = "insert"
            elif key == ord("O"):
                self._insert_line(self.cursor_y, "")
                self.cursor_x = 0
                self.mode = "insert"
            elif key == ord("d") and self.prev_key == ord("d"):
                if self.cursor_y < len(self.lines):
                    self.clipboard = self.lines[self.cursor_y]
                    self._delete_line(self.cursor_y)
                    if self.cursor_y >= len(self.lines):
                        self.cursor_y = max(0, len(self.lines) - 1)
                    self.cursor_x = 0
            elif key == ord("y") and self.prev_key == ord("y"):
                if self.cursor_y < len(self.lines):
                    self.clipboard = self.lines[self.cursor_y]
            elif key == ord("p"):
                self._insert_line(self.cursor_y + 1, self.clipboard)
                self.cursor_y += 1
                self.cursor_x = 0
            elif key == ord("P"):
                self._insert_line(self.cursor_y, self.clipboard)
                self.cursor_x = 0
            elif key == ord("w"):
                self._move_word_forward()
            elif key == ord("b"):
                self._move_word_backward()
            elif key == ord("0"):
                self.cursor_x = 0
            elif key == ord("$"):
                self.cursor_x = len(self.lines[self.cursor_y])
            elif key == ord("g"):
                if self.prev_key == ord("g"):
                    self.cursor_y = 0
                    self.cursor_x = 0
            elif key == ord("G"):
                self.cursor_y = max(0, len(self.lines) - 1)
                self.cursor_x = 0
            elif key == ord("u"):
                self.undo()
            elif key == ord("r") and self.prev_key == 18:  # Ctrl-R
                self.redo()

            self.prev_key = key
        except Exception:
            pass

    def _move_word_forward(self):
        """Move cursor forward by word."""
        if self.cursor_y >= len(self.lines):
            return
        line = self.lines[self.cursor_y]
        i = self.cursor_x
        # Skip non-alphanumeric
        while i < len(line) and not line[i].isalnum():
            i += 1
        # Skip alphanumeric
        while i < len(line) and line[i].isalnum():
            i += 1
        self.cursor_x = i

    def _move_word_backward(self):
        """Move cursor backward by word."""
        if self.cursor_y >= len(self.lines):
            return
        line = self.lines[self.cursor_y]
        i = max(0, self.cursor_x - 1)
        # Skip non-alphanumeric
        while i >= 0 and not line[i].isalnum():
            i -= 1
        # Skip alphanumeric
        while i >= 0 and line[i].isalnum():
            i -= 1
        self.cursor_x = max(0, i + 1)

    def handle_insert(self, key):
        """Handle insert mode keys."""
        try:
            if key == 27:  # ESC
                self.mode = "normal"
                if self.cursor_x > 0:
                    self.cursor_x -= 1
            elif key == 10 or key == 13:  # Enter
                self._split_line()
            elif key == curses.KEY_BACKSPACE or key == 127 or key == 8:
                self._backspace()
            elif 32 <= key <= 126:
                char = chr(key)
                self._insert_char(char)
        except Exception:
            pass

    def handle_command(self, key):
        """Handle command mode keys."""
        try:
            if key == 10 or key == 13:  # Enter
                cmd = self.command[1:].strip()
                if cmd in ["q", "q!"]:
                    self.running = False
                elif cmd == "w":
                    self._save_file()
                elif cmd in ["wq", "wq!", "x", "xq", "x!"]:
                    self._save_file()
                    self.running = False
                elif cmd.startswith("w "):
                    self.filename = cmd[2:].strip()
                    self._save_file()
                self.mode = "normal"
                self.command = ""
            elif key == 27:  # ESC
                self.mode = "normal"
                self.command = ""
            elif key == curses.KEY_BACKSPACE or key == 127 or key == 8:
                if len(self.command) > 1:
                    self.command = self.command[:-1]
            elif 32 <= key <= 126:
                self.command += chr(key)
        except Exception:
            self.mode = "normal"
            self.command = ""

    def move_cursor(self, dy, dx):
        """Move cursor with bounds checking."""
        if not self.lines:
            self.lines = [""]

        new_y = self.cursor_y + dy
        new_x = self.cursor_x + dx

        # Ensure valid Y position
        if 0 <= new_y < len(self.lines):
            self.cursor_y = new_y
            # Ensure valid X position for new line
            max_x = len(self.lines[self.cursor_y])
            self.cursor_x = max(0, min(new_x, max_x))
        elif new_y < 0:
            self.cursor_y = 0
            self.cursor_x = 0
        elif new_y >= len(self.lines):
            self.cursor_y = max(0, len(self.lines) - 1)
            self.cursor_x = len(self.lines[self.cursor_y])

    def save_state(self):
        """Save current state for undo."""
        with self.lock:
            state = {
                "lines": list(self.lines),
                "cursor_y": self.cursor_y,
                "cursor_x": self.cursor_x,
            }
            self.undo_stack.append(state)
            if len(self.undo_stack) > self.max_undo:
                self.undo_stack.pop(0)
            self.redo_stack.clear()

    def undo(self):
        """Undo last change."""
        with self.lock:
            if self.undo_stack:
                current_state = {
                    "lines": list(self.lines),
                    "cursor_y": self.cursor_y,
                    "cursor_x": self.cursor_x,
                }
                self.redo_stack.append(current_state)
                state = self.undo_stack.pop()
                self.lines = state["lines"]
                self.cursor_y = min(state["cursor_y"], len(self.lines) - 1)
                self.cursor_x = min(
                    state["cursor_x"],
                    len(self.lines[self.cursor_y]) if self.lines else 0,
                )

    def redo(self):
        """Redo last undone change."""
        with self.lock:
            if self.redo_stack:
                current_state = {
                    "lines": list(self.lines),
                    "cursor_y": self.cursor_y,
                    "cursor_x": self.cursor_x,
                }
                self.undo_stack.append(current_state)
                state = self.redo_stack.pop()
                self.lines = state["lines"]
                self.cursor_y = min(state["cursor_y"], len(self.lines) - 1)
                self.cursor_x = min(
                    state["cursor_x"],
                    len(self.lines[self.cursor_y]) if self.lines else 0,
                )

    def _insert_text(self, text):
        """Insert text at cursor position."""
        if not text:
            return

        self.save_state()
        lines = text.split("\n")

        if len(lines) == 1:
            # Single line insert
            if self.cursor_y >= len(self.lines):
                self.lines.append("")
                self.cursor_y = len(self.lines) - 1

            line = self.lines[self.cursor_y]
            self.lines[self.cursor_y] = line[: self.cursor_x] + text + line[self.cursor_x :]
            self.cursor_x += len(text)
        else:
            # Multi-line insert
            if self.cursor_y >= len(self.lines):
                self.lines.append("")
                self.cursor_y = len(self.lines) - 1

            first = self.lines[self.cursor_y][: self.cursor_x] + lines[0]
            last = lines[-1] + self.lines[self.cursor_y][self.cursor_x :]

            self.lines[self.cursor_y] = first
            for i in range(1, len(lines) - 1):
                self.lines.insert(self.cursor_y + i, lines[i])
            self.lines.insert(self.cursor_y + len(lines) - 1, last)

            self.cursor_y += len(lines) - 1
            self.cursor_x = len(lines[-1])

    def insert_text(self, text):
        """Thread-safe text insertion."""
        try:
            self.client_sock.send(pickle.dumps({"command": "insert_text", "text": text}))
        except:
            with self.lock:
                self._insert_text(text)

    def _delete_char(self):
        """Delete character at cursor."""
        self.save_state()
        if self.cursor_y < len(self.lines) and self.cursor_x < len(self.lines[self.cursor_y]):
            line = self.lines[self.cursor_y]
            self.lines[self.cursor_y] = line[: self.cursor_x] + line[self.cursor_x + 1 :]

    def delete_char(self):
        """Thread-safe character deletion."""
        try:
            self.client_sock.send(pickle.dumps({"command": "delete_char"}))
        except:
            with self.lock:
                self._delete_char()

    def _insert_char(self, char):
        """Insert single character."""
        if self.cursor_y >= len(self.lines):
            self.lines.append("")
            self.cursor_y = len(self.lines) - 1

        line = self.lines[self.cursor_y]
        self.lines[self.cursor_y] = line[: self.cursor_x] + char + line[self.cursor_x :]
        self.cursor_x += 1

    def _split_line(self):
        """Split line at cursor."""
        if self.cursor_y >= len(self.lines):
            self.lines.append("")
            self.cursor_y = len(self.lines) - 1

        line = self.lines[self.cursor_y]
        self.lines[self.cursor_y] = line[: self.cursor_x]
        self.lines.insert(self.cursor_y + 1, line[self.cursor_x :])
        self.cursor_y += 1
        self.cursor_x = 0

    def _backspace(self):
        """Handle backspace key."""
        if self.cursor_x > 0:
            line = self.lines[self.cursor_y]
            self.lines[self.cursor_y] = line[: self.cursor_x - 1] + line[self.cursor_x :]
            self.cursor_x -= 1
        elif self.cursor_y > 0:
            prev_len = len(self.lines[self.cursor_y - 1])
            self.lines[self.cursor_y - 1] += self.lines[self.cursor_y]
            del self.lines[self.cursor_y]
            self.cursor_y -= 1
            self.cursor_x = prev_len

    def _insert_line(self, line_num, text):
        """Insert a new line."""
        self.save_state()
        line_num = max(0, min(line_num, len(self.lines)))
        self.lines.insert(line_num, text)

    def _delete_line(self, line_num):
        """Delete a line."""
        self.save_state()
        if 0 <= line_num < len(self.lines):
            if len(self.lines) > 1:
                del self.lines[line_num]
            else:
                self.lines = [""]

    def _set_text(self, text):
        """Set entire text content."""
        self.save_state()
        self.lines = text.splitlines() if text else [""]
        self.cursor_y = 0
        self.cursor_x = 0

    def set_text(self, text):
        """Thread-safe text setting."""
        if not self.running:
            with self.lock:
                self._set_text(text)
            return
        try:
            self.client_sock.send(pickle.dumps({"command": "set_text", "text": text}))
        except:
            with self.lock:
                self._set_text(text)

    def _goto_line(self, line_num):
        """Go to specific line."""
        line_num = max(0, min(line_num - 1, len(self.lines) - 1))
        self.cursor_y = line_num
        self.cursor_x = 0

    def goto_line(self, line_num):
        """Thread-safe goto line."""
        try:
            self.client_sock.send(pickle.dumps({"command": "goto_line", "line_num": line_num}))
        except:
            with self.lock:
                self._goto_line(line_num)

    def get_text(self):
        """Get entire text content."""
        try:
            self.client_sock.send(pickle.dumps({"command": "get_text"}))
            data = self.client_sock.recv(65536)
            return pickle.loads(data)
        except:
            with self.lock:
                return "\n".join(self.lines)

    def get_cursor(self):
        """Get cursor position."""
        try:
            self.client_sock.send(pickle.dumps({"command": "get_cursor"}))
            data = self.client_sock.recv(4096)
            return pickle.loads(data)
        except:
            with self.lock:
                return (self.cursor_y, self.cursor_x)

    def get_file_info(self):
        """Get file information."""
        try:
            self.client_sock.send(pickle.dumps({"command": "get_file_info"}))
            data = self.client_sock.recv(4096)
            return pickle.loads(data)
        except:
            with self.lock:
                return {
                    "filename": self.filename,
                    "lines": len(self.lines),
                    "cursor": (self.cursor_y, self.cursor_x),
                    "mode": self.mode,
                }

    def socket_listener(self):
        """Listen for socket commands with error handling."""
        while self.running:
            try:
                data = self.server_sock.recv(65536)
                if not data:
                    break
                command = pickle.loads(data)
                self.command_queue.put(command)
            except socket.timeout:
                continue
            except OSError:
                if self.running:
                    continue
                else:
                    break
            except Exception:
                continue

    def execute_command(self, command):
        """Execute command with error handling."""
        try:
            cmd = command.get("command")

            if cmd == "insert_text":
                self._insert_text(command.get("text", ""))
            elif cmd == "delete_char":
                self._delete_char()
            elif cmd == "save_file":
                self._save_file()
            elif cmd == "set_text":
                self._set_text(command.get("text", ""))
            elif cmd == "goto_line":
                self._goto_line(command.get("line_num", 1))
            elif cmd == "get_text":
                result = "\n".join(self.lines)
                self.server_sock.send(pickle.dumps(result))
            elif cmd == "get_cursor":
                result = (self.cursor_y, self.cursor_x)
                self.server_sock.send(pickle.dumps(result))
            elif cmd == "get_file_info":
                result = {
                    "filename": self.filename,
                    "lines": len(self.lines),
                    "cursor": (self.cursor_y, self.cursor_x),
                    "mode": self.mode,
                }
                self.server_sock.send(pickle.dumps(result))
            elif cmd == "stop":
                self.running = False
        except Exception:
            pass

    # Additional public methods for backwards compatibility

    def move_cursor_to(self, y, x):
        """Move cursor to specific position."""
        with self.lock:
            self.cursor_y = max(0, min(y, len(self.lines) - 1))
            self.cursor_x = max(0, min(x, len(self.lines[self.cursor_y])))

    def get_line(self, line_num):
        """Get specific line."""
        with self.lock:
            if 0 <= line_num < len(self.lines):
                return self.lines[line_num]
            return None

    def get_lines(self, start, end):
        """Get range of lines."""
        with self.lock:
            start = max(0, start)
            end = min(end, len(self.lines))
            return self.lines[start:end]

    def insert_at_line(self, line_num, text):
        """Insert text at specific line."""
        with self.lock:
            self.save_state()
            line_num = max(0, min(line_num, len(self.lines)))
            self.lines.insert(line_num, text)

    def delete_lines(self, start, end):
        """Delete range of lines."""
        with self.lock:
            self.save_state()
            start = max(0, start)
            end = min(end, len(self.lines))
            if start < end:
                del self.lines[start:end]
                if not self.lines:
                    self.lines = [""]

    def replace_text(self, start_line, start_col, end_line, end_col, new_text):
        """Replace text in range."""
        with self.lock:
            self.save_state()

            # Validate bounds
            start_line = max(0, min(start_line, len(self.lines) - 1))
            end_line = max(0, min(end_line, len(self.lines) - 1))

            if start_line == end_line:
                line = self.lines[start_line]
                start_col = max(0, min(start_col, len(line)))
                end_col = max(0, min(end_col, len(line)))
                self.lines[start_line] = line[:start_col] + new_text + line[end_col:]
            else:
                first_part = self.lines[start_line][:start_col]
                last_part = self.lines[end_line][end_col:]
                new_lines = new_text.split("\n")
                self.lines[start_line] = first_part + new_lines[0]
                del self.lines[start_line + 1 : end_line + 1]
                for i, new_line in enumerate(new_lines[1:], 1):
                    self.lines.insert(start_line + i, new_line)
                if len(new_lines) > 1:
                    self.lines[start_line + len(new_lines) - 1] += last_part
                else:
                    self.lines[start_line] += last_part

    def search(self, pattern, start_line=0):
        """Search for pattern in text."""
        with self.lock:
            results = []
            try:
                for i in range(start_line, len(self.lines)):
                    matches = re.finditer(pattern, self.lines[i])
                    for match in matches:
                        results.append((i, match.start(), match.end()))
            except re.error:
                pass
            return results

    def replace_all(self, search_text, replace_text):
        """Replace all occurrences of text."""
        with self.lock:
            self.save_state()
            for i in range(len(self.lines)):
                self.lines[i] = self.lines[i].replace(search_text, replace_text)

    def select_range(self, start_line, start_col, end_line, end_col):
        """Select text range."""
        with self.lock:
            self.selection_start = (start_line, start_col)
            self.selection_end = (end_line, end_col)

    def get_selection(self):
        """Get selected text."""
        with self.lock:
            if not self.selection_start or not self.selection_end:
                return ""

            sl, sc = self.selection_start
            el, ec = self.selection_end

            # Validate bounds
            if sl < 0 or sl >= len(self.lines) or el < 0 or el >= len(self.lines):
                return ""

            if sl == el:
                return self.lines[sl][sc:ec]

            result = [self.lines[sl][sc:]]
            for i in range(sl + 1, el):
                if i < len(self.lines):
                    result.append(self.lines[i])
            if el < len(self.lines):
                result.append(self.lines[el][:ec])
            return "\n".join(result)

    def delete_selection(self):
        """Delete selected text."""
        with self.lock:
            if not self.selection_start or not self.selection_end:
                return
            self.save_state()
            sl, sc = self.selection_start
            el, ec = self.selection_end
            if 0 <= sl < len(self.lines) and 0 <= el < len(self.lines):
                self.replace_text(sl, sc, el, ec, "")
            self.selection_start = None
            self.selection_end = None

    def apply_search_replace_block(self, search_block, replace_block):
        """Apply search and replace on block."""
        with self.lock:
            self.save_state()
            search_lines = search_block.splitlines()
            replace_lines = replace_block.splitlines()

            for i in range(len(self.lines) - len(search_lines) + 1):
                match = True
                for j, search_line in enumerate(search_lines):
                    if i + j >= len(self.lines):
                        match = False
                        break
                    if self.lines[i + j].strip() != search_line.strip():
                        match = False
                        break

                if match:
                    # Preserve indentation
                    indent = len(self.lines[i]) - len(self.lines[i].lstrip())
                    indented_replace = [" " * indent + line for line in replace_lines]
                    self.lines[i : i + len(search_lines)] = indented_replace
                    return True
            return False

    def apply_diff(self, diff_text):
        """Apply unified diff."""
        with self.lock:
            self.save_state()
            try:
                lines = diff_text.split("\n")
                start_line = 0

                for line in lines:
                    if line.startswith("@@"):
                        match = re.search(r"@@ -(\d+),?(\d*) \+(\d+),?(\d*) @@", line)
                        if match:
                            start_line = int(match.group(1)) - 1
                    elif line.startswith("-"):
                        if start_line < len(self.lines):
                            del self.lines[start_line]
                    elif line.startswith("+"):
                        self.lines.insert(start_line, line[1:])
                        start_line += 1
                    elif line and not line.startswith("\\"):
                        start_line += 1
            except Exception:
                pass

    def get_context(self, line_num, context_lines=3):
        """Get lines around specific line."""
        with self.lock:
            start = max(0, line_num - context_lines)
            end = min(len(self.lines), line_num + context_lines + 1)
            return self.get_lines(start, end)

    def count_lines(self):
        """Count total lines."""
        with self.lock:
            return len(self.lines)

    def close(self):
        """Close the editor."""
        self.stop()

    def is_running(self):
        """Check if editor is running."""
        return self.running

    def wait(self, timeout=None):
        """Wait for editor to finish."""
        if self.thread and self.thread.is_alive():
            self.thread.join(timeout=timeout)
            return not self.thread.is_alive()
        return True

    def __enter__(self):
        """Context manager entry."""
        self.start()
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        """Context manager exit."""
        if exc_type:
            self._exception_occurred = True
        self.stop()
        return False

    def __del__(self):
        """Destructor for cleanup."""
        self._cleanup()


def main():
    """Main entry point with error handling."""
    editor = None
    try:
        filename = sys.argv[1] if len(sys.argv) > 1 else None

        # Parse additional arguments
        auto_save = "--auto-save" in sys.argv

        # Create and start editor
        editor = RPEditor(filename, auto_save=auto_save)
        editor.start()

        # Wait for editor to finish
        if editor.thread:
            editor.thread.join()

    except KeyboardInterrupt:
        pass
    except Exception as e:
        print(f"Error: {e}", file=sys.stderr)
    finally:
        if editor:
            editor.stop()
        # Ensure screen is cleared
        os.system("clear" if os.name != "nt" else "cls")


if __name__ == "__main__":
    if "rpe" in sys.argv[0]:
        main()