"""
Main menu screen for the NEXUS AUTOPARTS console application.

Displays a numbered Pick-style menu with navigation options for all
application sections.  Number keys jump directly; arrow keys move the
selection; ENTER activates.
"""

from console.core.screens import Screen
from console.core.keybindings import Key
from console.config import APP_NAME, APP_SUBTITLE, VERSION


# Menu items: list of (display_number, label, screen_name).
# Separators use display_number None and screen_name None.
_MENU_ITEMS = [
    ("1", "Consulta por Vehiculo",          "vehiculo_nav"),
    ("2", "Busqueda por Numero de Parte",   "buscar_parte"),
    ("3", "Busqueda por Descripcion",       "buscar_texto"),
    ("4", "Decodificador VIN",              "vin_decoder"),
    ("5", "Catalogo de Categorias",         "catalogo"),
    (None, None, None),  # separator
    ("6", "Administracion de Partes",       "admin_partes"),
    ("7", "Administracion de Fabricantes",  "admin_fabricantes"),
    ("8", "Cross-References",               "admin_crossref"),
    ("9", "Importar / Exportar Datos",      "admin_import"),
    (None, None, None),  # separator
    ("0", "Estadisticas del Sistema",       "estadisticas"),
]

# Quick lookup: digit character -> screen name
_KEY_MAP = {item[0]: item[2] for item in _MENU_ITEMS if item[0] is not None}

# Footer key labels
_FOOTER = [
    ("F1", "Ayuda"),
    ("F3", "Buscar"),
    ("F10", "Menu"),
    ("ESC", "Salir"),
]


class MenuPrincipalScreen(Screen):
    """Main menu screen with numbered items and arrow-key navigation."""

    def __init__(self):
        super().__init__(name="menu", title="Menu Principal")
        self._selected = 0  # index into _MENU_ITEMS (skipping separators)

    # ------------------------------------------------------------------
    # Helpers
    # ------------------------------------------------------------------

    def _selectable_indices(self):
        """Return list of indices in _MENU_ITEMS that are not separators."""
        return [i for i, item in enumerate(_MENU_ITEMS) if item[0] is not None]

    def _move_selection(self, direction):
        """Move selection up (-1) or down (+1), skipping separators."""
        indices = self._selectable_indices()
        if not indices:
            return
        try:
            pos = indices.index(self._selected)
        except ValueError:
            pos = 0
        pos = max(0, min(len(indices) - 1, pos + direction))
        self._selected = indices[pos]

    # ------------------------------------------------------------------
    # Screen interface
    # ------------------------------------------------------------------

    def render(self, context, db, renderer):
        # Header
        renderer.draw_header(
            f" {APP_NAME} v{VERSION}",
            f"{APP_SUBTITLE} ",
        )

        # Build items list for draw_menu.
        # Separators use the special "---" marker understood by the renderer.
        menu_items = []
        for num, label, _screen in _MENU_ITEMS:
            if num is None:
                menu_items.append(("---", ""))
            else:
                menu_items.append((num, label))

        renderer.draw_menu(
            menu_items,
            selected_index=self._selected,
            title="MENU PRINCIPAL",
        )

        # Footer
        renderer.draw_footer(_FOOTER)

    def on_key(self, key, context, db, renderer, nav):
        # --- Number keys: direct navigation ---
        if 48 <= key <= 57:  # ord('0') .. ord('9')
            digit = chr(key)
            screen_name = _KEY_MAP.get(digit)
            if screen_name:
                label = next(
                    (lbl for num, lbl, _ in _MENU_ITEMS if num == digit),
                    screen_name,
                )
                return (screen_name, {}, label)

        # --- Arrow keys ---
        if key == Key.UP:
            self._move_selection(-1)
            return None

        if key == Key.DOWN:
            self._move_selection(1)
            return None

        # --- ENTER: activate selected ---
        if key == Key.ENTER:
            item = _MENU_ITEMS[self._selected]
            num, label, screen_name = item
            if screen_name is not None:
                return (screen_name, {}, label)
            return None

        # --- ESC: quit confirmation ---
        if key == Key.ESCAPE:
            confirmed = renderer.show_message(
                "Desea salir de la aplicacion?", "confirm"
            )
            if confirmed:
                return "quit"
            return None

        return None