from PyQt6.QtWidgets import QLineEdit, QListWidget, QListWidgetItem
from PyQt6.QtCore import Qt, pyqtSignal
from loguru import logger


class SearchableCombo(QLineEdit):
    """
    Campo testo con popup filtrato.
    Il popup è un child widget della finestra contenitore — funziona
    anche dentro dialog modali.
    Emette item_selected(name, item_id) quando l'utente sceglie una voce.
    """

    item_selected = pyqtSignal(str, str)
    MIN_CHARS = 3

    def __init__(self, parent=None):
        super().__init__(parent)
        self._items: list[tuple[str, str]] = []
        self._selected_id: str = ""
        self._popup: QListWidget | None = None
        self.textEdited.connect(self._on_text_edited)

    # ── API pubblica ────────────────────────────────────────────────────────

    def set_items(self, items: list[tuple[str, str]]):
        self._items = items
        self._selected_id = ""

    def selected_id(self) -> str:
        return self._selected_id

    def reset(self):
        self.clear()
        self._selected_id = ""
        self._hide_popup()

    # ── Popup (child della finestra contenitore) ────────────────────────────

    def _ensure_popup(self):
        # Crea il popup come child della finestra top-level — così è
        # accessibile anche dentro dialog modali
        win = self.window()
        if self._popup is None or self._popup.parent() is not win:
            if self._popup:
                self._popup.hide()
                self._popup.deleteLater()
            self._popup = QListWidget(win)
            self._popup.setFocusPolicy(Qt.FocusPolicy.NoFocus)
            self._popup.itemClicked.connect(self._on_item_clicked)
            self._popup.hide()

    def _show_popup(self):
        win = self.window()
        # Posizione relativa alla finestra contenitore
        pos = self.mapTo(win, self.rect().bottomLeft())
        self._popup.move(pos)
        self._popup.setFixedWidth(max(self.width(), 300))
        row_h = self._popup.sizeHintForRow(0) or 22
        n = min(self._popup.count(), 10)
        self._popup.setFixedHeight(n * row_h + 6)
        self._popup.raise_()
        self._popup.show()

    def _hide_popup(self):
        if self._popup:
            self._popup.hide()

    # ── Logica filtro ───────────────────────────────────────────────────────

    def _on_text_edited(self, text: str):
        self._selected_id = ""
        if len(text) < self.MIN_CHARS:
            self._hide_popup()
            return

        text_lower = text.lower()
        matches = [(n, i) for n, i in self._items if text_lower in n.lower()]

        if not matches:
            self._hide_popup()
            return

        self._ensure_popup()
        self._popup.clear()
        for name, item_id in matches:
            item = QListWidgetItem(name)
            item.setData(Qt.ItemDataRole.UserRole, item_id)
            self._popup.addItem(item)

        self._show_popup()
        logger.debug(f"SearchableCombo: {len(matches)} risultati per '{text}'")

    def _on_item_clicked(self, item: QListWidgetItem):
        name = item.text()
        item_id = item.data(Qt.ItemDataRole.UserRole)
        self._selected_id = item_id
        self.setText(name)
        self._hide_popup()
        self.item_selected.emit(name, item_id)
        logger.debug(f"SearchableCombo: selezionato '{name}' id={item_id}")

    # ── Tastiera ────────────────────────────────────────────────────────────

    def keyPressEvent(self, event):
        if self._popup and self._popup.isVisible():
            if event.key() == Qt.Key.Key_Down:
                self._popup.setFocus()
                self._popup.setCurrentRow(0)
                return
            if event.key() == Qt.Key.Key_Escape:
                self._hide_popup()
                return
        super().keyPressEvent(event)

    def hideEvent(self, event):
        self._hide_popup()
        super().hideEvent(event)