Basic implementation of road based transfers.

This adds the models and UIs for creating ground unit transfer orders.
Most of the feature is still missing:

* The AI doesn't do them.
* Transfers can move across the whole map in one turn.
* Transfers between disconnected bases are allowed.
* Transfers are not modeled in the simulation, so they can't be
  interdicted.

https://github.com/Khopa/dcs_liberation/issues/824

qt_ui/windows/PendingTransfersDialog.py

@@ -0,0 +1,189 @@
+from typing import Optional
+
+from PySide2.QtCore import (
+    QItemSelection,
+    QItemSelectionModel,
+    QModelIndex,
+    QSize,
+    Qt,
+)
+from PySide2.QtGui import QContextMenuEvent, QFont, QFontMetrics, QIcon, QPainter
+from PySide2.QtWidgets import (
+    QAbstractItemView,
+    QAction,
+    QDialog,
+    QHBoxLayout,
+    QListView,
+    QMenu,
+    QPushButton,
+    QStyle,
+    QStyleOptionViewItem,
+    QStyledItemDelegate,
+    QVBoxLayout,
+)
+
+from game.transfers import RoadTransferOrder
+from qt_ui.delegate_helpers import painter_context
+from qt_ui.models import GameModel, TransferModel
+
+
+class TransferDelegate(QStyledItemDelegate):
+    FONT_SIZE = 10
+    HMARGIN = 4
+    VMARGIN = 4
+
+    def __init__(self, transfer_model: TransferModel) -> None:
+        super().__init__()
+        self.transfer_model = transfer_model
+
+    def get_font(self, option: QStyleOptionViewItem) -> QFont:
+        font = QFont(option.font)
+        font.setPointSize(self.FONT_SIZE)
+        return font
+
+    @staticmethod
+    def transfer(index: QModelIndex) -> RoadTransferOrder:
+        return index.data(TransferModel.TransferRole)
+
+    def first_row_text(self, index: QModelIndex) -> str:
+        return self.transfer_model.data(index, Qt.DisplayRole)
+
+    def second_row_text(self, index: QModelIndex) -> str:
+        transfer = self.transfer(index)
+        return f"Currently at {transfer.origin}. Arrives at destination in 1 turn."
+
+    def paint(
+        self, painter: QPainter, option: QStyleOptionViewItem, index: QModelIndex
+    ) -> None:
+        # Draw the list item with all the default selection styling, but with an
+        # invalid index so text formatting is left to us.
+        super().paint(painter, option, QModelIndex())
+
+        rect = option.rect.adjusted(
+            self.HMARGIN, self.VMARGIN, -self.HMARGIN, -self.VMARGIN
+        )
+
+        with painter_context(painter):
+            painter.setFont(self.get_font(option))
+
+            icon: Optional[QIcon] = index.data(Qt.DecorationRole)
+            if icon is not None:
+                icon.paint(
+                    painter,
+                    rect,
+                    Qt.AlignLeft | Qt.AlignVCenter,
+                    self.icon_mode(option),
+                    self.icon_state(option),
+                )
+
+            rect = rect.adjusted(self.icon_size(option).width() + self.HMARGIN, 0, 0, 0)
+            painter.drawText(rect, Qt.AlignLeft, self.first_row_text(index))
+            line2 = rect.adjusted(0, rect.height() / 2, 0, rect.height() / 2)
+            painter.drawText(line2, Qt.AlignLeft, self.second_row_text(index))
+
+    @staticmethod
+    def icon_mode(option: QStyleOptionViewItem) -> QIcon.Mode:
+        if not (option.state & QStyle.State_Enabled):
+            return QIcon.Disabled
+        elif option.state & QStyle.State_Selected:
+            return QIcon.Selected
+        elif option.state & QStyle.State_Active:
+            return QIcon.Active
+        return QIcon.Normal
+
+    @staticmethod
+    def icon_state(option: QStyleOptionViewItem) -> QIcon.State:
+        return QIcon.On if option.state & QStyle.State_Open else QIcon.Off
+
+    @staticmethod
+    def icon_size(option: QStyleOptionViewItem) -> QSize:
+        icon_size: Optional[QSize] = option.decorationSize
+        if icon_size is None:
+            return QSize(0, 0)
+        else:
+            return icon_size
+
+    def sizeHint(self, option: QStyleOptionViewItem, index: QModelIndex) -> QSize:
+        left = self.icon_size(option).width() + self.HMARGIN
+        metrics = QFontMetrics(self.get_font(option))
+        first = metrics.size(0, self.first_row_text(index))
+        second = metrics.size(0, self.second_row_text(index))
+        text_width = max(first.width(), second.width())
+        return QSize(
+            left + text_width + 2 * self.HMARGIN,
+            first.height() + second.height() + 2 * self.VMARGIN,
+        )
+
+
+class PendingTransfersList(QListView):
+    """List view for displaying the pending unit transfers."""
+
+    def __init__(self, transfer_model: TransferModel) -> None:
+        super().__init__()
+        self.transfer_model = transfer_model
+
+        self.setItemDelegate(TransferDelegate(self.transfer_model))
+        self.setModel(self.transfer_model)
+        self.selectionModel().setCurrentIndex(
+            self.transfer_model.index(0, 0, QModelIndex()), QItemSelectionModel.Select
+        )
+
+        # self.setIconSize(QSize(91, 24))
+        self.setSelectionBehavior(QAbstractItemView.SelectItems)
+
+    def contextMenuEvent(self, event: QContextMenuEvent) -> None:
+        index = self.indexAt(event.pos())
+
+        menu = QMenu("Menu")
+
+        delete_action = QAction("Cancel")
+        delete_action.triggered.connect(lambda: self.cancel_transfer(index))
+        menu.addAction(delete_action)
+
+        menu.exec_(event.globalPos())
+
+    def cancel_transfer(self, index: QModelIndex) -> None:
+        """Cancels the given transfer order."""
+        self.transfer_model.cancel_transfer_at_index(index)
+
+
+class PendingTransfersDialog(QDialog):
+    """Dialog window showing all scheduled transfers for the player."""
+
+    def __init__(self, game_model: GameModel, parent=None) -> None:
+        super().__init__(parent)
+        self.transfer_model = game_model.transfer_model
+
+        self.setMinimumSize(1000, 440)
+        self.setWindowTitle(f"Pending Transfers")
+        # TODO: self.setWindowIcon()
+
+        layout = QVBoxLayout()
+        self.setLayout(layout)
+
+        self.transfer_list = PendingTransfersList(self.transfer_model)
+        self.transfer_list.selectionModel().selectionChanged.connect(
+            self.on_selection_changed
+        )
+        layout.addWidget(self.transfer_list)
+
+        button_layout = QHBoxLayout()
+        layout.addLayout(button_layout)
+
+        button_layout.addStretch()
+
+        self.cancel_button = QPushButton("Cancel Transfer")
+        self.cancel_button.setProperty("style", "btn-danger")
+        self.cancel_button.clicked.connect(self.on_cancel_transfer)
+        self.cancel_button.setEnabled(self.transfer_model.rowCount() > 0)
+        button_layout.addWidget(self.cancel_button)
+
+    def on_cancel_transfer(self) -> None:
+        """Cancels the selected transfer order."""
+        self.transfer_model.cancel_transfer_at_index(self.transfer_list.currentIndex())
+
+    def on_selection_changed(
+        self, selected: QItemSelection, _deselected: QItemSelection
+    ) -> None:
+        """Updates the state of the delete button."""
+        self.cancel_button.setEnabled(not selected.empty())