"""Small, size-aware widgets used by the generation workspace."""
from __future__ import annotations

from PySide6.QtCore import QRect, QSize, Qt
from PySide6.QtGui import QColor, QPainter, QPainterPath, QPixmap
from PySide6.QtWidgets import (
    QFrame, QHBoxLayout, QLabel, QListWidget, QSizePolicy,
    QStyledItemDelegate, QStyle, QVBoxLayout, QWidget,
)


class ImagePreview(QWidget):
    """Paint an image without letting its pixel dimensions enlarge the layout."""

    def __init__(self, text: str = "No image selected", parent=None):
        super().__init__(parent)
        self._image = QPixmap()
        self._text = text
        self.setSizePolicy(QSizePolicy.Ignored, QSizePolicy.Expanding)
        self.setMinimumSize(80, 80)

    def sizeHint(self):
        return QSize(360, 260)

    def setPixmap(self, image: QPixmap):
        self._image = image
        self.update()

    def setText(self, text: str):
        self._text = text
        self.update()

    def paintEvent(self, event):
        painter = QPainter(self)
        painter.setRenderHint(QPainter.Antialiasing)
        painter.fillRect(self.rect(), QColor("#040d15"))
        if self._image.isNull():
            painter.setPen(QColor("#89a7bc"))
            painter.drawText(self.rect().adjusted(18, 12, -18, -12), Qt.AlignCenter | Qt.TextWordWrap, self._text)
            return
        size = self._image.size()
        size.scale(self.size() - QSize(12, 12), Qt.KeepAspectRatio)
        destination = QRect(0, 0, size.width(), size.height())
        destination.moveCenter(self.rect().center())
        painter.setRenderHint(QPainter.SmoothPixmapTransform)
        painter.drawPixmap(destination, self._image)


class ElidedLabel(QLabel):
    """Single-line metadata that cannot force a panel wider than its contents."""

    def __init__(self, text="", parent=None):
        super().__init__(text, parent)
        self.setSizePolicy(QSizePolicy.Ignored, QSizePolicy.Preferred)
        self.setMinimumWidth(0)
        self.setMinimumHeight(20)
        self.setTextFormat(Qt.PlainText)

    def setText(self, text):
        super().setText(text)
        self.setToolTip(text)

    def paintEvent(self, event):
        painter = QPainter(self)
        painter.setPen(self.palette().color(self.foregroundRole()))
        painter.drawText(self.contentsRect(), Qt.AlignVCenter | Qt.AlignLeft,
                         self.fontMetrics().elidedText(self.text(), Qt.ElideRight, self.contentsRect().width()))


def section(number: str, title: str, subtitle: str):
    card = QFrame()
    card.setObjectName("GenerationSection")
    layout = QVBoxLayout(card)
    layout.setContentsMargins(12, 10, 12, 12)
    layout.setSpacing(8)
    header = QHBoxLayout()
    badge = QLabel(number)
    badge.setObjectName("GenerationNumber")
    badge.setAlignment(Qt.AlignCenter)
    badge.setFixedSize(30, 30)
    header.addWidget(badge)
    labels = QVBoxLayout()
    labels.setSpacing(0)
    heading = QLabel(title)
    heading.setObjectName("GenerationHeading")
    labels.addWidget(heading)
    if subtitle:
        detail = QLabel(subtitle)
        detail.setProperty("muted", True)
        detail.setWordWrap(True)
        labels.addWidget(detail)
    header.addLayout(labels, 1)
    layout.addLayout(header)
    return card, layout, header


def field(label: str, widget: QWidget):
    container = QWidget()
    layout = QVBoxLayout(container)
    layout.setContentsMargins(0, 0, 0, 0)
    layout.setSpacing(4)
    layout.addWidget(QLabel(label))
    layout.addWidget(widget)
    container.setMinimumWidth(0)
    return container


class GeneratorCardDelegate(QStyledItemDelegate):
    def sizeHint(self, option, index):
        size = self.parent().gridSize()
        return QSize(max(176, size.width()), 182)

    def paint(self, painter, option, index):
        painter.save()
        painter.setRenderHint(QPainter.Antialiasing)
        rect = option.rect.adjusted(4, 4, -4, -4)
        selected = bool(option.state & QStyle.State_Selected)
        hovered = bool(option.state & QStyle.State_MouseOver)
        painter.setPen(QColor("#16b7f2" if selected or hovered else "#204c68"))
        painter.setBrush(QColor("#0b2030" if selected or hovered else "#081925"))
        painter.drawRoundedRect(rect, 7, 7)
        image_rect = rect.adjusted(5, 5, -5, -69)
        icon = index.data(Qt.DecorationRole)
        if icon:
            image = icon.pixmap(QSize(480, 240))
            if not image.isNull():
                image = image.scaled(image_rect.size(), Qt.KeepAspectRatioByExpanding, Qt.SmoothTransformation)
                painter.save()
                clip = QPainterPath()
                clip.addRoundedRect(image_rect, 4, 4)
                painter.setClipPath(clip)
                painter.drawPixmap(image_rect.center().x() - image.width() // 2,
                                   image_rect.center().y() - image.height() // 2, image)
                painter.restore()
        lines = str(index.data(Qt.DisplayRole) or "").split("\n")
        painter.setPen(QColor("#edf5fb"))
        font = painter.font()
        font.setBold(True)
        painter.setFont(font)
        painter.drawText(rect.adjusted(10, rect.height() - 64, -10, -42), Qt.AlignVCenter,
                         painter.fontMetrics().elidedText(lines[0], Qt.ElideRight, rect.width() - 20))
        font.setBold(False)
        painter.setFont(font)
        painter.setPen(QColor("#94b3c9"))
        painter.drawText(rect.adjusted(10, rect.height() - 43, -10, -22), Qt.AlignVCenter,
                         lines[1] if len(lines) > 1 else "")
        painter.setPen(QColor("#38c4ff"))
        painter.drawText(rect.adjusted(10, rect.height() - 24, -10, -3), Qt.AlignVCenter, "Open  →")
        painter.restore()


class GeneratorCards(QListWidget):
    def __init__(self):
        super().__init__()
        self.setViewMode(QListWidget.IconMode)
        self.setResizeMode(QListWidget.Adjust)
        self.setMovement(QListWidget.Static)
        self.setMouseTracking(True)
        self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        self.setItemDelegate(GeneratorCardDelegate(self))
        self.setGridSize(QSize(220, 182))
        self.setMinimumHeight(190)
        self.setMaximumHeight(212)

    def resizeEvent(self, event):
        super().resizeEvent(event)
        self.fit_cards()

    def keyPressEvent(self, event):
        if event.key() in (Qt.Key_Return, Qt.Key_Enter) and self.currentItem() is not None:
            self.itemClicked.emit(self.currentItem())
            event.accept()
            return
        super().keyPressEvent(event)

    def fit_cards(self):
        available = max(180, self.viewport().width() - 14)
        columns = max(1, min(max(1, self.count()), 4, available // 176))
        self.setGridSize(QSize(available // columns, 182))