from copy import copy
import json
from os import path, makedirs

from AnyQt.QtGui import QImage, QPainter
from AnyQt.QtWidgets import QGraphicsScene, QApplication, QWidget, QGraphicsView, QHBoxLayout
from AnyQt.QtCore import QRectF, Qt, QTimer
# QWebEngineWidgets must be imported before QCoreApplication is created.
# It will fail with an import error if imported (first time) after.
import AnyQt.QtWebEngineWidgets  # pylint: disable=unused-import

from orangecanvas.canvas.items import NodeItem
from orangecanvas.help import HelpManager
from orangecanvas.registry import WidgetRegistry

from Orange.canvas.config import Config as OConfig


class WidgetCatalog:
    def __init__(self, output_dir, image_url_prefix):
        self.output_dir = output_dir
        self.image_url_prefix = image_url_prefix

        QApplication.setAttribute(Qt.AA_EnableHighDpiScaling)
        QApplication.setAttribute(Qt.AA_UseHighDpiPixmaps)
        QApplication.setAttribute(Qt.AA_ShareOpenGLContexts)
        self.app = QApplication([])

        print("Generating widget repository")
        self.registry = self.__get_widget_registry()
        print("Locating help files")
        self.help_manager = HelpManager()
        self.help_manager.set_registry(self.registry)

        # Help manager needs QApplication running to get the urls
        # of widget documentation. 5 seconds should be enough.
        QTimer.singleShot(5000, self.app.quit)
        self.app.exec()

        self.__scene = QGraphicsScene()
        self.__nodes = []
        print("Ready to go")

    def create(self):
        print("Generating catalog")
        try:
            makedirs(path.join(self.output_dir, "icons"))
        except FileExistsError:
            pass

        result = []
        for category in self.registry.categories():
            widgets = []
            result.append((category.name, widgets))
            for widget in category.widgets:
                widgets.append({
                    "text": widget.name,
                    "doc": self.__get_help(widget),
                    "img": self.__get_icon(widget, category),
                    "keyword": widget.keywords,
                })

        with open(path.join(self.output_dir, "widgets.json"), 'wt') as f:
            json.dump(result, f, indent=1)
        print("Done")

    @staticmethod
    def __get_widget_registry():
        widget_registry = WidgetRegistry()
        widget_discovery = OConfig.widget_discovery(widget_registry)
        widget_discovery.run(OConfig.widgets_entry_points())

        # Fixup category.widgets list
        for cat, widgets in widget_registry._categories_dict.values():
            cat.widgets = widgets
        return widget_registry

    def __get_icon(self, widget, category=None):
        # Set remove inputs/outputs so the "ears" are not drawn
        widget = copy(widget)
        widget.inputs = []
        widget.outputs = []

        w = IconWidget()
        w.set_widget(widget, category)
        w.show()
        #self.app.processEvents()
        filename = "icons/{}.png".format(widget.qualified_name)
        w.render_as_png(path.join(self.output_dir, filename))
        w.hide()

        if self.image_url_prefix:
            return self.image_url_prefix + filename
        else:
            return filename

    def __get_help(self, widget):
        query = dict(id=widget.qualified_name)
        try:
            return self.help_manager.search(query).url()
        except KeyError:
            return None


class IconWidget(QWidget):
    def __init__(self):
        super().__init__()
        self.setLayout(QHBoxLayout())
        self.layout().setContentsMargins(0, 0, 0, 0)
        self.setFixedSize(50, 50)

        view = QGraphicsView()
        self.layout().addWidget(view)
        self.scene = QGraphicsScene(view)
        view.setScene(self.scene)

    def set_widget(self, widget_description, category_description):
        node = NodeItem(widget_description)
        if category_description is not None:
            node.setWidgetCategory(category_description)
        self.scene.addItem(node)

    def render_as_png(self, filename):
        img = QImage(50, 50, QImage.Format_ARGB32)
        img.fill(Qt.transparent)
        painter = QPainter(img)
        painter.setRenderHint(QPainter.Antialiasing, 1)
        self.scene.render(painter, QRectF(0, 0, 50, 50), QRectF(-25, -25, 50, 50))
        painter.end()
        img.save(filename)


if __name__ == '__main__':
    from optparse import OptionParser

    parser = OptionParser(usage="usage: %prog --output <outputdir> [options]")
    parser.add_option('--url-prefix', dest="prefix",
                      help="prefix to prepend to image urls")
    parser.add_option('--output', dest="output",
                      help="path where widgets.json will be created")

    options, args = parser.parse_args()
    if not options.output:
        parser.error("Please specify the output dir")

    w = WidgetCatalog(output_dir=options.output, image_url_prefix=options.prefix)
    w.create()