from __future__ import annotations

import json
from collections.abc import Callable

from PySide6.QtCore import QMimeData, QModelIndex, Qt

from bedit_core.models import Component
from bedit_gui.services.component_clipboard import COMPONENTS_MIME
from bedit_gui.views.models.document_tree_model import DocumentTreeModel

PayloadFactory = Callable[[list[Component]], dict]


class LibraryTreeModel(DocumentTreeModel):
    def __init__(self, payload_factory: PayloadFactory) -> None:
        super().__init__(editable=False)
        self._payload_factory = payload_factory

    def flags(self, index: QModelIndex) -> Qt.ItemFlag:
        flags = super().flags(index)
        if isinstance(self.value(index), Component):
            flags |= Qt.ItemFlag.ItemIsDragEnabled
        return flags

    def mimeTypes(self) -> list[str]:
        return [COMPONENTS_MIME]

    def mimeData(self, indexes: list[QModelIndex]) -> QMimeData:
        rows = [index for index in indexes if index.column() == 0 and isinstance(self.value(index), Component)]
        selected = {id(self.value(index)) for index in rows}
        components = []
        added = set()
        for index in rows:
            parent = index.parent()
            if any(id(self.value(parent_index)) in selected for parent_index in self._parents(parent)):
                continue
            component = self.value(index)
            if isinstance(component, Component) and id(component) not in added:
                components.append(component)
                added.add(id(component))
        mime = QMimeData()
        if components:
            mime.setData(COMPONENTS_MIME, json.dumps(self._payload_factory(components)).encode("utf-8"))
            mime.setText("\n".join(component.name for component in components))
        return mime

    def supportedDragActions(self) -> Qt.DropAction:
        return Qt.DropAction.CopyAction

    @staticmethod
    def _parents(index: QModelIndex):
        while index.isValid():
            yield index
            index = index.parent()