"""
ModeScreen – the single unified screen used for all tool_mode values.
Shows the appropriate pane(s) based on the mode:
  - backup_only:      Backup pane only
  - direct_transfer:  Migrate pane only
  - backup_transfer:  Both panes with a toggle button to switch between them
"""

from pathlib import Path

from textual.app import ComposeResult
from textual.containers import Container, Horizontal, VerticalScroll
from textual.widgets import Header, Footer, Button, ContentSwitcher, Rule
from textual.screen import Screen

from src.core.configuration import load_config
from src.ui.backup_ops import BackupPane
from src.ui.shuttle_ops import ShuttlePane


class ModeScreen(Screen):
    """Unified mode screen — adapts content based on tool_mode."""

    CSS = """
    #main_outer {
        align: center top;
        height: 100%;
    }
    #main_container {
        width: 80%;
        height: 100%;
        layout: vertical;
        min-height: 20;
        border: solid green;
        padding: 1 2;
        margin: 2 0;
    }
    #switcher {
        height: 1fr;
    }
    #bottom_actions {
        height: auto;
        dock: bottom;
        margin: 1 1 0 1;
    }
    #bottom_actions Button, #btn_switch {
        width: 1fr;
        margin: 0 1;
    }

    ModalScreen {
        align: center middle;
    }
    #progress_dialog, #shuttle_config_dialog, #platform_select_dialog, #submenu_dialog, #confirm_dialog, #chanpick_dialog, #channel_dialog {
        width: 80%;
        height: 100%;
        layout: vertical;
        border: solid green;
        padding: 1 2;
        margin: 2 0;
        background: $surface;
    }
    #progress_status { text-style: bold; margin-bottom: 1; }
    #progress_bar { margin-bottom: 1; }
    #progress_loader { margin-bottom: 1; }
    #progress_log { height: 1fr; margin-bottom: 1; border: solid $primary; }
    #chanpick_scroll {
        height: 1fr;
        border: solid $primary;
        margin-bottom: 1;
        padding: 0 1;
    }
    .category_header {
        margin-top: 1;
        background: $primary 10%;
        text-style: bold;
        padding-left: 1;
    }
    #config_title, #platform_title, #submenu_title, #confirm_msg, #chanpick_title, #chan_title {
        text-style: bold; margin-bottom: 1;
    }
    #config_buttons, #confirm_buttons, #chanpick_buttons {
        height: auto; margin-top: 1;
    }
    #config_buttons Button, #confirm_buttons Button, #chanpick_buttons Button {
        width: 1fr; margin: 0 1;
    }
    #channel_list_scroll {
        height: 1fr;
        border: solid $primary;
        margin-bottom: 1;
        padding: 0 1;
    }
    #select_all_buttons { height: auto; margin-bottom: 1; }
    #select_all_buttons Button { width: auto; margin-right: 1; }

    RadioButton:focus { background: transparent; border: none; }
    RadioButton > .radio-button--label { padding: 0 1; }
    RadioButton:focus > .radio-button--label { background: transparent; text-style: none; }
    """

    BINDINGS = [
        ("q", "app.exit", "Quit"),
    ]

    def __init__(self, cfg_name: str, cfg_path: Path, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.cfg_name = cfg_name
        self.config_path = cfg_path
        self.config = load_config(cfg_path)
        self._showing_backup = True  # track which pane is visible in combined mode

    def compose(self) -> ComposeResult:
        yield Header(show_clock=True)

        mode = self.config.tool_mode or "backup_only"

        with Container(id="main_outer"):
            with Container(id="main_container"):
                if mode == "backup_only":
                    yield BackupPane(self.cfg_name, self.config_path, id="pane_backup")
                elif mode == "direct_transfer":
                    yield ShuttlePane(self.cfg_name, self.config_path, id="pane_migrate")
                else:  # backup_transfer
                    with ContentSwitcher(initial="pane_backup", id="switcher"):
                        yield BackupPane(self.cfg_name, self.config_path, id="pane_backup")
                        yield ShuttlePane(self.cfg_name, self.config_path, id="pane_migrate")
                
                yield Rule()
                with Horizontal(id="bottom_actions"):
                    if mode == "backup_transfer":
                        yield Button("Switch to Migrate ⇄", id="btn_switch", variant="primary")
                    yield Button("Configuration", id="btn_config", variant="success")
                    yield Button("Exit", id="btn_exit", variant="error")

        yield Footer()

    def on_button_pressed(self, event: Button.Pressed) -> None:
        bid = event.button.id
        if bid == "btn_exit":
            self.app.exit()
        elif bid == "btn_config":
            from src.ui.main_app import ConfigScreen
            def reload_screen(saved: bool = False):
                if saved:
                    new_cfg = load_config(self.config_path)
                    if new_cfg.tool_mode != self.config.tool_mode:
                        self.app.pop_screen()
                        from src.ui.mode_screen import ModeScreen
                        self.app.push_screen(ModeScreen(self.cfg_name, self.config_path))
                    else:
                        self.config = new_cfg
                        for pane in self.query(BackupPane):
                            pane.reload_config()
                        for pane in self.query(ShuttlePane):
                            pane.reload_config()
            self.app.push_screen(ConfigScreen(self.cfg_name, self.config_path), reload_screen)
        elif bid == "btn_switch":
            self._toggle_pane()

    def _toggle_pane(self) -> None:
        """Switch between Backup and Migrate panes in backup_transfer mode."""
        switcher = self.query_one("#switcher", ContentSwitcher)
        btn = self.query_one("#btn_switch", Button)
        if self._showing_backup:
            switcher.current = "pane_migrate"
            btn.label = "Switch to Backup ⇄"
            self._showing_backup = False
        else:
            switcher.current = "pane_backup"
            btn.label = "Switch to Migrate ⇄"
            self._showing_backup = True