# vim: set fileencoding=utf-8 :
###############################################################################
#                                                                             #
# Copyright (c) 2019 Idiap Research Institute, http://www.idiap.ch/           #
# Contact: beat.support@idiap.ch                                              #
#                                                                             #
# This file is part of the beat.editor module of the BEAT platform.           #
#                                                                             #
# Commercial License Usage                                                    #
# Licensees holding valid commercial BEAT licenses may use this file in       #
# accordance with the terms contained in a written agreement between you      #
# and Idiap. For further information contact tto@idiap.ch                     #
#                                                                             #
# Alternatively, this file may be used under the terms of the GNU Affero      #
# Public License version 3 as published by the Free Software and appearing    #
# in the file LICENSE.AGPL included in the packaging of this file.            #
# The BEAT platform is distributed in the hope that it will be useful, but    #
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY  #
# or FITNESS FOR A PARTICULAR PURPOSE.                                        #
#                                                                             #
# You should have received a copy of the GNU Affero Public License along      #
# with the BEAT platform. If not, see http://www.gnu.org/licenses/.           #
#                                                                             #
###############################################################################

import simplejson as json

from enum import Enum

from PyQt5.QtCore import Qt
from PyQt5.QtCore import QRect
from PyQt5.QtCore import QRectF
from PyQt5.QtCore import QPointF
from PyQt5.QtCore import pyqtSignal

from PyQt5.QtGui import QColor
from PyQt5.QtGui import QBrush
from PyQt5.QtGui import QPen
from PyQt5.QtGui import QFont
from PyQt5.QtGui import QFontMetrics
from PyQt5.QtGui import QPainterPath
from PyQt5.QtGui import QTransform

from PyQt5.QtWidgets import QVBoxLayout
from PyQt5.QtWidgets import QWidget
from PyQt5.QtWidgets import QGraphicsView
from PyQt5.QtWidgets import QGraphicsItem
from PyQt5.QtWidgets import QGraphicsPathItem
from PyQt5.QtWidgets import QGraphicsObject

from ..backend.asset import AssetType
from ..backend.assetmodel import AssetModel
from ..decorators import frozen

from .editor import AbstractAssetEditor
from .drawing_space import DrawingSpace


class BasePin(QGraphicsObject):
    """Base class for pin graphics"""

    dataChanged = pyqtSignal()

    def __init__(self, parent, pin, block, pin_brush, pin_pen):

        super().__init__(parent=parent)

        # Highlight
        self.setAcceptHoverEvents(True)

        # Storage
        self.pin_type = None
        self.pin = pin
        self.block = block
        self.brush = pin_brush
        self.pen = pin_pen
        self.block_object = parent

    def shape(self):
        """Define the circle shape of a Pin object"""

        path = QPainterPath()
        path.addRect(self.boundingRect())
        return path

    def paint(self, painter, option, widget):
        """Paint the Pin"""

        painter.setBrush(self.brush)
        painter.setPen(self.pen)

        painter.drawEllipse(self.boundingRect())

    def mousePressEvent(self, event):
        """Painting connection initiated"""

        self.new_connection = Connection(self.block_object.connection_style)
        self.block_object.scene().addItem(self.new_connection)

    def mouseMoveEvent(self, event):
        """Painting connection in progress"""

        # Only one single connection allowed from input pin
        if isinstance(self, InputPin):
            # Check if connection exist and remove if it does
            for connection in self.block_object.toolchain.connections:
                if (
                    connection.end_block == self.block_object
                    and connection.end_pin == self
                ):
                    self.block_object.toolchain.connections.remove(connection)
                    self.block_object.scene().removeItem(connection)
                    self.dataChanged.emit()

        mouse_position = self.mapToScene(event.pos())
        self.new_connection.set_new_connection_pins_coordinates(self, mouse_position)

    def mouseReleaseEvent(self, event):
        """Painting connection ended - validation required"""

        self.block_object.scene().removeItem(self.new_connection)
        target = self.block_object.scene().itemAt(
            event.scenePos().toPoint(), QTransform()
        )

        if isinstance(target, BasePin):

            if isinstance(self, OutputPin):
                start = self
                end = target
            else:
                start = target
                end = self

            if Connection(self.block_object.connection_style).check_validity(
                start, end
            ):

                # Find the corresponding channel
                connection_settings = {}
                if start.block_object.type == BlockType.DATASETS.name:
                    connection_settings["channel"] = start.block_object.name
                else:
                    connection_settings[
                        "channel"
                    ] = start.block_object.synchronized_channel

                # Create the connection
                connection_settings["from"] = start.block + "." + start.pin
                connection_settings["to"] = end.block + "." + end.pin

                channel_colors = self.block_object.toolchain.json_object[
                    "representation"
                ]["channel_colors"]

                connection = Connection(self.block_object.connection_style)
                connection.load(
                    self.block_object.toolchain, connection_settings, channel_colors
                )

                self.dataChanged.emit()

                self.block_object.toolchain.connections.append(connection)
                self.block_object.toolchain.scene.addItem(connection)

    def get_center_point(self):
        """Get the center coordinates of the Pin(x,y)"""

        rect = self.boundingRect()
        pin_center_point = QPointF(
            rect.x() + rect.width() / 2.0, rect.y() + rect.height() / 2.0
        )

        return self.mapToScene(pin_center_point)


class InputPin(BasePin):
    def __init__(self, parent, pin, block, pin_brush, pin_pen):

        super().__init__(parent, pin, block, pin_brush, pin_pen)

    def boundingRect(self):
        """Bounding rect around pin object"""

        height = self.block_object.height / 2.0
        width = height

        x = -(width / 2.0)
        y = (
            self.block_object.height
            + self.block_object.inputs.index(self.pin) * self.block_object.height
        )

        rect = QRectF(QRect(x, y, width, height))
        return rect


class OutputPin(BasePin):
    def __init__(self, parent, pin, block, pin_brush, pin_pen):

        super().__init__(parent, pin, block, pin_brush, pin_pen)

    def boundingRect(self):
        """ bounding rect width by height.
        """

        height = self.block_object.height / 2.0
        width = height

        x = self.block_object.custom_width - (width / 2.0)
        y = (
            self.block_object.height
            + self.block_object.outputs.index(self.pin) * self.block_object.height
        )

        rect = QRectF(QRect(x, y, width, height))
        return rect


class Connection(QGraphicsPathItem):
    def __init__(self, style):

        super().__init__()

        self.start_block_name = None
        self.start_pin_name = None
        self.start_pin_center_point = None
        self.end_block_name = None
        self.end_pin_name = None
        self.end_pin_center_point = None
        self.channel = None

        self.connection_color = []

        self.set_style(style)

    def set_style(self, config):

        # Highlight
        self.setAcceptHoverEvents(True)

        # Geometry and color settings
        self.connection_color = config["color"]

        self.connection_pen = QPen()
        self.connection_pen.setColor(QColor(*self.connection_color))
        self.connection_pen.setWidth(config["width"])

    def drawCubicBezierCurve(self):

        self.setPen(self.connection_pen)

        path = QPainterPath()
        middle_point_x = (
            self.end_pin_center_point.x() - self.start_pin_center_point.x()
        ) / 2.0
        middle_point_y = (
            self.end_pin_center_point.y() - self.start_pin_center_point.y()
        ) / 2.0
        second_middle_point_y = (
            self.end_pin_center_point.y() - self.start_pin_center_point.y()
        ) / 4.0
        control_point = QPointF(middle_point_x, middle_point_y)
        second_control_point = QPointF(middle_point_x, second_middle_point_y)
        path.moveTo(self.start_pin_center_point)
        path.cubicTo(
            self.start_pin_center_point + control_point,
            self.end_pin_center_point - second_control_point,
            self.end_pin_center_point,
        )

        self.setPath(path)

    def set_moved_block_pins_coordinates(self):
        self.start_pin_center_point = self.start_pin.get_center_point()
        self.end_pin_center_point = self.end_pin.get_center_point()

        self.drawCubicBezierCurve()

    def set_new_connection_pins_coordinates(self, selected_pin, mouse_position):

        if isinstance(selected_pin, OutputPin):
            self.start_block_name = selected_pin.block
            self.start_pin_name = selected_pin.pin
            self.start_pin = selected_pin
            self.start_pin_center_point = self.start_pin.get_center_point()
            self.end_pin_center_point = mouse_position
        if isinstance(selected_pin, InputPin):
            self.end_block_name = selected_pin.block
            self.end_pin_name = selected_pin.pin
            self.end_pin = selected_pin
            self.end_pin_center_point = self.end_pin.get_center_point()
            self.start_pin_center_point = mouse_position

        self.drawCubicBezierCurve()

    def check_validity(self, start, end):

        # remove input-input and output-output connection
        if type(start) == type(end):
            return False

        # remove connection to same block object
        if start.block_object == end.block_object:
            return False

        # check if end block pin is free
        toolchain = end.block_object.toolchain
        for connection in toolchain.connections:
            if connection.end_block == end.block_object and connection.end_pin == end:
                return False

        return True

    def load(self, toolchain, connection_details, channel_colors):

        self.start_block_name = connection_details["from"].split(".")[0]
        self.start_pin_name = connection_details["from"].split(".")[1]
        self.end_block_name = connection_details["to"].split(".")[0]
        self.end_pin_name = connection_details["to"].split(".")[1]
        self.channel = connection_details["channel"]

        hexadecimal = channel_colors[self.channel].lstrip("#")
        hlen = len(hexadecimal)
        self.connection_color = list(
            int(hexadecimal[i : i + hlen // 3], 16) for i in range(0, hlen, hlen // 3)
        )
        self.connection_color.append(255)
        self.connection_pen.setColor(QColor(*self.connection_color))

        self.blocks = toolchain.blocks

        for block in self.blocks:
            if block.name == self.start_block_name:
                self.start_block = block
            elif block.name == self.end_block_name:
                self.end_block = block

        self.start_pin = self.start_block.pins["outputs"][self.start_pin_name]
        self.end_pin = self.end_block.pins["inputs"][self.end_pin_name]

        self.start_pin_center_point = self.start_pin.get_center_point()
        self.end_pin_center_point = self.end_pin.get_center_point()

        self.drawCubicBezierCurve()

        self.start_block.blockMoved.connect(self.set_moved_block_pins_coordinates)
        self.end_block.blockMoved.connect(self.set_moved_block_pins_coordinates)


class BlockType(Enum):
    """All possible block types"""

    BLOCKS = "blocks"
    ANALYZERS = "analyzers"
    DATASETS = "datasets"

    @classmethod
    def from_name(cls, name):
        try:
            return cls[name]
        except ValueError:
            raise ValueError("{} is not a valid block type".format(name))


class Block(QGraphicsObject):
    """Block item"""

    dataChanged = pyqtSignal()
    blockMoved = pyqtSignal()

    def __init__(self, toolchain, block_details, block_type, style, connection_style):
        super().__init__()

        # Block information
        self.toolchain = toolchain

        self.name = block_details["name"]
        if block_type == BlockType.DATASETS.name:
            self.inputs = None
        else:
            self.inputs = block_details["inputs"]
        if block_type == BlockType.ANALYZERS.name:
            self.outputs = None
        else:
            self.outputs = block_details["outputs"]

        if "synchronized_channel" in block_details:
            self.synchronized_channel = block_details["synchronized_channel"]
        else:
            self.synchronized_channel = None
        self.type = block_type
        self.style = style
        self.connection_style = connection_style

        self.position = QPointF(0, 0)
        self.pins = dict()
        self.pins["inputs"] = dict()
        self.pins["outputs"] = dict()

        self.set_style(style)
        self.create_pins()

    def create_pins(self):

        if self.inputs is not None:
            for pin_name in self.inputs:
                input_pin = InputPin(
                    self, pin_name, self.name, self.pin_brush, self.pin_pen
                )
                self.pins["inputs"][pin_name] = input_pin

                input_pin.dataChanged.connect(self.dataChanged)

        if self.outputs is not None:
            for pin_name in self.outputs:
                output_pin = OutputPin(
                    self, pin_name, self.name, self.pin_brush, self.pin_pen
                )
                self.pins["outputs"][pin_name] = output_pin

                output_pin.dataChanged.connect(self.dataChanged)

    def set_style(self, config):

        self.setAcceptHoverEvents(True)
        self.setFlag(QGraphicsItem.ItemIsSelectable, True)
        self.setFlag(QGraphicsItem.ItemIsMovable)

        # Geometry settings
        self.width = config["width"]
        self.height = config["height"]
        self.border = config["border"]
        self.radius = config["radius"]
        self.pin_height = config["pin_height"]

        self.text_font = QFont(config["font"], config["font_size"], QFont.Bold)
        self.pin_font = QFont(config["pin_font"], config["pin_font_size"], QFont.Normal)

        metrics = QFontMetrics(self.text_font)
        text_width = metrics.boundingRect(self.name).width() + 14

        if self.inputs is not None:
            self.max_inputs_width = (
                metrics.boundingRect(max(self.inputs, key=len)).width() + 14
            )
        else:
            self.max_inputs_width = 14

        if self.outputs is not None:
            self.max_outputs_width = (
                metrics.boundingRect(max(self.outputs, key=len)).width() + 14
            )
        else:
            self.max_outputs_width = 14

        self.custom_width = max(
            self.max_outputs_width + self.max_inputs_width, text_width
        )

        self.center = QPointF()
        self.center.setX(self.custom_width / 2.0)
        self.center.setY(self.height / 2.0)

        self.background_brush = QBrush()
        self.background_brush.setStyle(Qt.SolidPattern)

        self.background_color_datasets = QColor(*config["background_color_datasets"])
        self.background_color_analyzers = QColor(*config["background_color_analyzers"])
        self.background_color_blocks = QColor(*config["background_color_blocks"])

        self.background_brush.setColor(self.background_color_blocks)

        self.background_pen = QPen()
        self.background_pen.setStyle(Qt.SolidLine)
        self.background_pen.setWidth(0)
        self.background_pen.setColor(QColor(*config["background_color"]))

        self.border_pen = QPen()
        self.border_pen.setStyle(Qt.SolidLine)
        self.border_pen.setWidth(self.border)
        self.border_pen.setColor(QColor(*config["border_color"]))

        self.selection_border_pen = QPen()
        self.selection_border_pen.setStyle(Qt.SolidLine)
        self.selection_border_pen.setWidth(self.border)
        self.selection_border_pen.setColor(QColor(*config["selection_border_color"]))

        self.text_pen = QPen()
        self.text_pen.setStyle(Qt.SolidLine)
        self.text_pen.setColor(QColor(*config["text_color"]))

        self._pin_brush = QBrush()
        self._pin_brush.setStyle(Qt.SolidPattern)

        self.pin_pen = QPen()
        self.pin_pen.setStyle(Qt.SolidLine)

        self.pin_brush = QBrush()
        self.pin_brush.setStyle(Qt.SolidPattern)
        self.pin_brush.setColor(QColor(*config["pin_color"]))

    def boundingRect(self):
        """Bounding rect of the block object width by height"""
        metrics = QFontMetrics(self.text_font)
        text_height = metrics.boundingRect(self.name).height() + 14

        if self.inputs is not None and self.outputs is not None:
            max_pin_height = max(len(self.inputs), len(self.outputs))
        elif self.inputs is not None and self.outputs is None:
            max_pin_height = len(self.inputs)
        elif self.inputs is None and self.outputs is not None:
            max_pin_height = len(self.outputs)
        else:
            max_pin_height = 0

        rect = QRect(
            0,
            -text_height,
            self.custom_width,
            text_height + self.height + max_pin_height * self.pin_height,
        )
        rect = QRectF(rect)
        return rect

    def draw_pins_name(self, painter, _type, data):
        """Paint pin with name"""
        offset = 0
        for pin_name in data:
            # Pin rect
            painter.setBrush(self.background_brush)
            painter.setPen(self.background_pen)
            painter.setFont(self.pin_font)

            coord_x = self.border / 2
            alignement = Qt.AlignLeft

            max_width = self.max_inputs_width
            if _type == "output":
                coord_x = self.custom_width - self.max_outputs_width - self.border / 2
                max_width = self.max_outputs_width
                alignement = Qt.AlignRight

            rect = QRect(
                coord_x, self.height - self.radius + offset, max_width, self.pin_height
            )

            textRect = QRect(
                rect.left() + self.radius,
                rect.top() + self.radius,
                rect.width() - 2 * self.radius,
                rect.height(),
            )

            painter.setPen(self.pin_pen)
            painter.drawText(textRect, alignement, pin_name)

            offset += self.pin_height

    def mouseMoveEvent(self, event):
        """Update connections due to new block position"""

        super(Block, self).mouseMoveEvent(event)

        self.position = self.scenePos()

        self.blockMoved.emit()
        self.dataChanged.emit()

    def paint(self, painter, option, widget):
        """Paint the block"""

        # Design tools
        if self.type == BlockType.DATASETS.name:
            self.background_brush.setColor(self.background_color_datasets)
        elif self.type == BlockType.ANALYZERS.name:
            self.background_brush.setColor(self.background_color_analyzers)

        painter.setBrush(self.background_brush)
        painter.setPen(self.border_pen)

        if self.inputs is not None and self.outputs is not None:
            max_pin_height = max(len(self.inputs), len(self.outputs))
        elif self.inputs is not None and self.outputs is None:
            max_pin_height = len(self.inputs)
        elif self.inputs is None and self.outputs is not None:
            max_pin_height = len(self.outputs)
        else:
            max_pin_height = 0

        if self.isSelected():
            self.selection_border_pen.setWidth(3)
            painter.setPen(self.selection_border_pen)
        else:
            self.border_pen.setWidth(0)
            painter.setPen(self.border_pen)

        painter.drawRoundedRect(
            0,
            0,
            self.custom_width,
            self.height + max_pin_height * self.pin_height,
            self.radius,
            self.radius,
        )

        # Block name
        painter.setPen(self.text_pen)
        painter.setFont(self.text_font)

        metrics = QFontMetrics(painter.font())
        text_width = metrics.boundingRect(self.name).width() + 14
        text_height = metrics.boundingRect(self.name).height() + 14
        margin = (text_width - self.custom_width) * 0.5
        text_rect = QRect(-margin, -text_height, text_width, text_height)

        painter.drawText(text_rect, Qt.AlignCenter, self.name)

        # Pin
        if self.inputs is not None:
            self.draw_pins_name(painter, "input", self.inputs)
        if self.outputs is not None:
            self.draw_pins_name(painter, "output", self.outputs)


class ToolchainView(QGraphicsView):
    def __init__(self, toolchain):
        super().__init__()

        self.toolchain = toolchain

    def wheelEvent(self, event):
        """In/Out zoom view using the mouse wheel"""

        self.setTransformationAnchor(QGraphicsView.AnchorUnderMouse)
        factor = (event.angleDelta().y() / 120) * 0.1
        self.scale(1 + factor, 1 + factor)

    def keyPressEvent(self, event):
        """Focus on the toolchain when F key pressed"""
        if event.key() == Qt.Key_F:
            self.custom_focus()

    def custom_focus(self):
        """Custom focus on toolchain"""

        selected_blocks = self.scene().selectedItems()
        if selected_blocks:
            x_list = []
            y_list = []
            width_list = []
            height_list = []
            for block in selected_blocks:
                x_list.append(block.scenePos().x())
                y_list.append(block.scenePos().y())
                width_list.append(block.boundingRect().width())
                height_list.append(block.boundingRect().height())
                min_x = min(x_list)
                min_y = min(y_list) + block.boundingRect().y()
                max_width = max(x_list) + max(width_list) - min_x
                max_height = max(y_list) + max(height_list) - min_y
            rect = QRectF(QRect(min_x, min_y, max_width, max_height))
            toolchain_focus = rect
        else:
            toolchain_focus = self.scene().itemsBoundingRect()

        self.fitInView(toolchain_focus, Qt.KeepAspectRatio)


class Toolchain(QWidget):
    """Toolchain designer"""

    dataChanged = pyqtSignal()

    def __init__(self, parent=None):
        super().__init__(parent=parent)

        self.json_object = {}

        with open("beat/editor/widgets/space_nodes_config.json") as json_file:
            config_data = json.load(json_file)

        self.scene_config = config_data["drawing_space_config"]
        self.scene = DrawingSpace(self.scene_config)

        self.block_config = config_data["block_config"]
        self.connection_config = config_data["connection_config"]

        self.view = ToolchainView(self)
        self.view.setScene(self.scene)
        layout = QVBoxLayout(self)
        layout.addWidget(self.view)

    def clear_space(self):
        self.scene.clear()
        self.scene.items().clear()
        self.blocks = []
        self.connections = []
        self.channels = []

    def load(self, json_object):
        """Parse the json in parameter and generates a graph"""

        self.json_object = json_object

        if "representation" in self.json_object:
            self.web_representation = self.json_object["representation"]
        else:
            self.web_representation = None

        if "editor_gui" in self.json_object:
            self.editor_gui = self.json_object["editor_gui"]
        else:
            self.editor_gui = None

        self.clear_space()

        # Get datasets, blocks, analyzers
        for block_type in BlockType:
            for block_item in self.json_object[block_type.value]:
                block = Block(
                    self,
                    block_item,
                    block_type.name,
                    self.block_config,
                    self.connection_config,
                )
                # Place blocks (x,y) if information is given
                if self.editor_gui is not None:
                    if block.name in self.editor_gui:
                        block.setPos(
                            self.editor_gui[block.name]["x"],
                            self.editor_gui[block.name]["y"],
                        )
                        block.position = block.scenePos()
                block.dataChanged.connect(self.dataChanged)
                self.blocks.append(block)
                self.scene.addItem(block)

        # Display connections
        connections = self.json_object["connections"]
        channel_colors = self.json_object["representation"]["channel_colors"]

        for connection_item in connections:
            connection = Connection(self.connection_config)
            connection.load(self, connection_item, channel_colors)
            self.connections.append(connection)
            self.scene.addItem(connection)

    def dump(self):
        """Returns the json used to load the widget"""

        data = {}

        if self.web_representation is not None:
            data["representation"] = self.web_representation

        data["editor_gui"] = {}

        for block_type in BlockType:
            block_type_list = []
            for block in self.blocks:
                block_data = {}
                if block_type == BlockType.from_name(block.type):
                    block_data["name"] = block.name
                    if block.synchronized_channel is not None:
                        block_data["synchronized_channel"] = block.synchronized_channel
                    if block.inputs is not None:
                        block_data["inputs"] = block.inputs
                    if block.outputs is not None:
                        block_data["outputs"] = block.outputs

                    block_type_list.append(block_data)
                data["editor_gui"][block.name] = {
                    "x": block.position.x(),
                    "y": block.position.y(),
                }
            data[block_type.value] = block_type_list

        connection_list = []
        for connection in self.connections:
            connection_data = {}
            connection_data["channel"] = connection.channel
            connection_data["from"] = (
                connection.start_block_name + "." + connection.start_pin_name
            )
            connection_data["to"] = (
                connection.end_block_name + "." + connection.end_pin_name
            )
            connection_list.append(connection_data)

        data["connections"] = connection_list

        return data


@frozen
class ToolchainEditor(AbstractAssetEditor):
    def __init__(self, parent=None):
        super().__init__(AssetType.TOOLCHAIN, parent)
        self.setObjectName(self.__class__.__name__)
        self.set_title(self.tr("Toolchain"))

        self.toolchain_model = AssetModel()
        self.toolchain_model.asset_type = AssetType.TOOLCHAIN

        self.toolchain = Toolchain()
        self.layout().addWidget(self.toolchain, 2)
        self.layout().addStretch()

        self.toolchain.dataChanged.connect(self.dataChanged)

    def _load_json(self, json_object):
        """Load the json object passed as parameter"""

        self.toolchain.load(json_object)

    def _dump_json(self):
        """Returns the json representation of the asset"""

        return self.toolchain.dump()