"""
Terminal tab — persistent interactive SSH shell via ShellSession + TerminalWidget.
"""

import queue
import threading
import time
import customtkinter as ctk
from core.ssh_client import ShellSession
from core.i18n import t


class TerminalTab(ctk.CTkFrame):
    def __init__(self, master, store):
        super().__init__(master, fg_color="transparent")
        self.store = store
        self._current_alias: str | None = None
        self._session: ShellSession | None = None
        self._reconnect_count = 0
        self._max_reconnect = 3
        self._intentional_disconnect = False

        # Import here to avoid circular issues
        from gui.widgets.terminal_widget import TerminalWidget

        self._terminal = TerminalWidget(
            self,
            send_callback=self._send_to_shell,
            resize_callback=self._on_resize,
        )
        self._terminal.pack(fill="both", expand=True, padx=5, pady=5)
        self._terminal.set_status(t("term_disconnected"), "#888888")

        # Thread-safe data queue
        self._data_queue: queue.Queue[bytes] = queue.Queue()

    def set_server(self, alias: str | None):
        if alias == self._current_alias:
            return
        self._disconnect()
        self._current_alias = alias
        if alias:
            self._connect()
        else:
            self._terminal.reset()
            self._terminal.set_status(t("term_disconnected"), "#888888")

    def _connect(self):
        if not self._current_alias:
            return
        server = self.store.get_server(self._current_alias)
        if not server:
            self._terminal.set_status(
                t("server_not_found").format(alias=self._current_alias), "#ff4444"
            )
            return

        alias = self._current_alias
        self._terminal.set_status(t("term_connecting").format(alias=alias), "#ccaa00")
        self._terminal.reset()
        self._intentional_disconnect = False

        def _do_connect():
            try:
                key_path = self.store.get_ssh_key_path()
                cols, rows = self._terminal.get_size()
                session = ShellSession(server, key_path, cols=cols, rows=rows)
                session.on_data = self._on_data_received
                session.on_disconnect = self._on_disconnected
                session.connect()

                # Set session on main thread to avoid races
                def _set_session():
                    self._session = session
                    self._reconnect_count = 0
                    self._terminal.set_status(
                        t("term_connected").format(alias=alias), "#44cc44"
                    )
                    self._terminal.focus_terminal()
                self.after(0, _set_session)
            except Exception as e:
                self.after(0, lambda: self._terminal.set_status(
                    t("term_connect_failed").format(error=str(e)), "#ff4444"
                ))

        threading.Thread(target=_do_connect, daemon=True).start()

    def _disconnect(self):
        self._intentional_disconnect = True
        session = self._session
        self._session = None
        if session:
            session.disconnect()

    def _on_data_received(self, data: bytes):
        """Called from SSH thread — put data in thread-safe queue."""
        self._data_queue.put(data)
        self.after(0, self._flush_data_queue)

    def _flush_data_queue(self):
        """Called on main thread — drain queue and feed terminal."""
        chunks = []
        try:
            while True:
                chunks.append(self._data_queue.get_nowait())
        except queue.Empty:
            pass
        if chunks:
            self._terminal.feed(b"".join(chunks))

    def _on_disconnected(self):
        """Called from SSH read thread."""
        def _handle():
            if self._intentional_disconnect:
                self._terminal.set_status(t("term_disconnected"), "#888888")
                return

            self._session = None

            if self._reconnect_count < self._max_reconnect:
                self._reconnect_count += 1
                n = self._reconnect_count
                mx = self._max_reconnect
                self._terminal.set_status(
                    t("term_reconnecting").format(n=n, max=mx), "#ccaa00"
                )

                def _retry():
                    time.sleep(1)
                    if not self._intentional_disconnect and self._current_alias:
                        self.after(0, self._connect)

                threading.Thread(target=_retry, daemon=True).start()
            else:
                self._terminal.set_status(t("term_reconnect_fail"), "#ff4444")

        self.after(0, _handle)

    def _send_to_shell(self, data: bytes):
        session = self._session  # local ref for thread safety
        if session and session.connected:
            session.send(data)

    def _on_resize(self, cols: int, rows: int):
        session = self._session  # local ref for thread safety
        if session and session.connected:
            session.resize(cols, rows)