from typing import List, Dict, Type

import pyqtgraph as pg

from vnpy.trader.ui import QtGui, QtWidgets, QtCore
from vnpy.trader.object import BarData

from .manager import BarManager
from .base import (
    GREY_COLOR, WHITE_COLOR, CURSOR_COLOR, BLACK_COLOR,
    to_int, NORMAL_FONT
)
from .axis import DatetimeAxis
from .item import ChartItem


pg.setConfigOptions(antialias=True)


class ChartWidget(pg.PlotWidget):
    """"""
    MIN_BAR_COUNT = 100

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

        self._manager: BarManager = BarManager()

        self._plots: Dict[str, pg.PlotItem] = {}
        self._items: Dict[str, ChartItem] = {}
        self._item_plot_map: Dict[ChartItem, pg.PlotItem] = {}

        self._first_plot: pg.PlotItem = None
        self._cursor: ChartCursor = None

        self._right_ix: int = 0                     # Index of most right data
        self._bar_count: int = self.MIN_BAR_COUNT   # Total bar visible in chart

        self._init_ui()

    def _init_ui(self) -> None:
        """"""
        self.setWindowTitle("ChartWidget of vn.py")

        self._layout = pg.GraphicsLayout()
        self._layout.setContentsMargins(10, 10, 10, 10)
        self._layout.setSpacing(0)
        self._layout.setBorder(color=GREY_COLOR, width=0.8)
        self._layout.setZValue(0)
        self.setCentralItem(self._layout)

        self._x_axis = DatetimeAxis(self._manager, orientation='bottom')

    def add_cursor(self) -> None:
        """"""
        if not self._cursor:
            self._cursor = ChartCursor(
                self, self._manager, self._plots, self._item_plot_map)

    def add_plot(
        self,
        plot_name: str,
        minimum_height: int = 80,
        maximum_height: int = None,
        hide_x_axis: bool = False
    ) -> None:
        """
        Add plot area.
        """
        # Create plot object
        plot = pg.PlotItem(axisItems={'bottom': self._x_axis})
        plot.setMenuEnabled(False)
        plot.setClipToView(True)
        plot.hideAxis('left')
        plot.showAxis('right')
        plot.setDownsampling(mode='peak')
        plot.setRange(xRange=(0, 1), yRange=(0, 1))
        plot.hideButtons()
        plot.setMinimumHeight(minimum_height)

        if maximum_height:
            plot.setMaximumHeight(maximum_height)

        if hide_x_axis:
            plot.hideAxis("bottom")

        if not self._first_plot:
            self._first_plot = plot

        # Connect view change signal to update y range function
        view = plot.getViewBox()
        view.sigXRangeChanged.connect(self._update_y_range)
        view.setMouseEnabled(x=True, y=False)

        # Set right axis
        right_axis = plot.getAxis('right')
        right_axis.setWidth(60)
        right_axis.tickFont = NORMAL_FONT

        # Connect x-axis link
        if self._plots:
            first_plot = list(self._plots.values())[0]
            plot.setXLink(first_plot)

        # Store plot object in dict
        self._plots[plot_name] = plot

        # Add plot onto the layout
        self._layout.nextRow()
        self._layout.addItem(plot)

    def add_item(
        self,
        item_class: Type[ChartItem],
        item_name: str,
        plot_name: str
    ):
        """
        Add chart item.
        """
        item = item_class(self._manager)
        self._items[item_name] = item

        plot = self._plots.get(plot_name)
        plot.addItem(item)

        self._item_plot_map[item] = plot

    def get_plot(self, plot_name: str) -> pg.PlotItem:
        """
        Get specific plot with its name.
        """
        return self._plots.get(plot_name, None)

    def get_all_plots(self) -> List[pg.PlotItem]:
        """
        Get all plot objects.
        """
        return self._plots.values()

    def clear_all(self) -> None:
        """
        Clear all data.
        """
        self._manager.clear_all()

        for item in self._items.values():
            item.clear_all()

        if self._cursor:
            self._cursor.clear_all()

    def update_history(self, history: List[BarData]) -> None:
        """
        Update a list of bar data.
        """
        self._manager.update_history(history)

        for item in self._items.values():
            item.update_history(history)

        self._update_plot_limits()

        self.move_to_right()

    def update_bar(self, bar: BarData) -> None:
        """
        Update single bar data.
        """
        self._manager.update_bar(bar)

        for item in self._items.values():
            item.update_bar(bar)

        self._update_plot_limits()

        if self._right_ix >= (self._manager.get_count() - self._bar_count / 2):
            self.move_to_right()

    def _update_plot_limits(self) -> None:
        """
        Update the limit of plots.
        """
        for item, plot in self._item_plot_map.items():
            min_value, max_value = item.get_y_range()

            plot.setLimits(
                xMin=-1,
                xMax=self._manager.get_count(),
                yMin=min_value,
                yMax=max_value
            )

    def _update_x_range(self) -> None:
        """
        Update the x-axis range of plots.
        """
        max_ix = self._right_ix
        min_ix = self._right_ix - self._bar_count

        for plot in self._plots.values():
            plot.setRange(xRange=(min_ix, max_ix), padding=0)

    def _update_y_range(self) -> None:
        """
        Update the y-axis range of plots.
        """
        view = self._first_plot.getViewBox()
        view_range = view.viewRange()

        min_ix = max(0, int(view_range[0][0]))
        max_ix = min(self._manager.get_count(), int(view_range[0][1]))

        # Update limit for y-axis
        for item, plot in self._item_plot_map.items():
            y_range = item.get_y_range(min_ix, max_ix)
            plot.setRange(yRange=y_range)

    def paintEvent(self, event: QtGui.QPaintEvent) -> None:
        """
        Reimplement this method of parent to update current max_ix value.
        """
        view = self._first_plot.getViewBox()
        view_range = view.viewRange()
        self._right_ix = max(0, view_range[0][1])

        super().paintEvent(event)

    def keyPressEvent(self, event: QtGui.QKeyEvent) -> None:
        """
        Reimplement this method of parent to move chart horizontally and zoom in/out.
        """
        if event.key() == QtCore.Qt.Key_Left:
            self._on_key_left()
        elif event.key() == QtCore.Qt.Key_Right:
            self._on_key_right()
        elif event.key() == QtCore.Qt.Key_Up:
            self._on_key_up()
        elif event.key() == QtCore.Qt.Key_Down:
            self._on_key_down()

    def wheelEvent(self, event: QtGui.QWheelEvent) -> None:
        """
        Reimplement this method of parent to zoom in/out.
        """
        delta = event.angleDelta()

        if delta.y() > 0:
            self._on_key_up()
        elif delta.y() < 0:
            self._on_key_down()

    def _on_key_left(self) -> None:
        """
        Move chart to left.
        """
        self._right_ix -= 1
        self._right_ix = max(self._right_ix, self._bar_count)

        self._update_x_range()
        self._cursor.move_left()
        self._cursor.update_info()

    def _on_key_right(self) -> None:
        """
        Move chart to right.
        """
        self._right_ix += 1
        self._right_ix = min(self._right_ix, self._manager.get_count())

        self._update_x_range()
        self._cursor.move_right()
        self._cursor.update_info()

    def _on_key_down(self) -> None:
        """
        Zoom out the chart.
        """
        self._bar_count *= 1.2
        self._bar_count = min(int(self._bar_count), self._manager.get_count())

        self._update_x_range()
        self._cursor.update_info()

    def _on_key_up(self) -> None:
        """
        Zoom in the chart.
        """
        self._bar_count /= 1.2
        self._bar_count = max(int(self._bar_count), self.MIN_BAR_COUNT)

        self._update_x_range()
        self._cursor.update_info()

    def move_to_right(self) -> None:
        """
        Move chart to the most right.
        """
        self._right_ix = self._manager.get_count()
        self._update_x_range()
        self._cursor.update_info()


class ChartCursor(QtCore.QObject):
    """"""

    def __init__(
        self,
        widget: ChartWidget,
        manager: BarManager,
        plots: Dict[str, pg.GraphicsObject],
        item_plot_map: Dict[ChartItem, pg.GraphicsObject]
    ):
        """"""
        super().__init__()

        self._widget: ChartWidget = widget
        self._manager: BarManager = manager
        self._plots: Dict[str, pg.GraphicsObject] = plots
        self._item_plot_map: Dict[ChartItem, pg.GraphicsObject] = item_plot_map

        self._x: int = 0
        self._y: int = 0
        self._plot_name: str = ""

        self._init_ui()
        self._connect_signal()

    def _init_ui(self):
        """"""
        self._init_line()
        self._init_label()
        self._init_info()

    def _init_line(self) -> None:
        """
        Create line objects.
        """
        self._v_lines: Dict[str, pg.InfiniteLine] = {}
        self._h_lines: Dict[str, pg.InfiniteLine] = {}
        self._views: Dict[str, pg.ViewBox] = {}

        pen = pg.mkPen(WHITE_COLOR)

        for plot_name, plot in self._plots.items():
            v_line = pg.InfiniteLine(angle=90, movable=False, pen=pen)
            h_line = pg.InfiniteLine(angle=0, movable=False, pen=pen)
            view = plot.getViewBox()

            for line in [v_line, h_line]:
                line.setZValue(0)
                line.hide()
                view.addItem(line)

            self._v_lines[plot_name] = v_line
            self._h_lines[plot_name] = h_line
            self._views[plot_name] = view

    def _init_label(self) -> None:
        """
        Create label objects on axis.
        """
        self._y_labels: Dict[str, pg.TextItem] = {}
        for plot_name, plot in self._plots.items():
            label = pg.TextItem(
                plot_name, fill=CURSOR_COLOR, color=BLACK_COLOR)
            label.hide()
            label.setZValue(2)
            label.setFont(NORMAL_FONT)
            plot.addItem(label, ignoreBounds=True)
            self._y_labels[plot_name] = label

        self._x_label: pg.TextItem = pg.TextItem(
            "datetime", fill=CURSOR_COLOR, color=BLACK_COLOR)
        self._x_label.hide()
        self._x_label.setZValue(2)
        self._x_label.setFont(NORMAL_FONT)
        plot.addItem(self._x_label, ignoreBounds=True)

    def _init_info(self) -> None:
        """
        """
        self._infos: Dict[str, pg.TextItem] = {}
        for plot_name, plot in self._plots.items():
            info = pg.TextItem(
                "info",
                color=CURSOR_COLOR,
                border=CURSOR_COLOR,
                fill=BLACK_COLOR
            )
            info.hide()
            info.setZValue(2)
            info.setFont(NORMAL_FONT)
            plot.addItem(info)  # , ignoreBounds=True)
            self._infos[plot_name] = info

    def _connect_signal(self) -> None:
        """
        Connect mouse move signal to update function.
        """
        self._widget.scene().sigMouseMoved.connect(self._mouse_moved)

    def _mouse_moved(self, evt: tuple) -> None:
        """
        Callback function when mouse is moved.
        """
        if not self._manager.get_count():
            return

        # First get current mouse point
        pos = evt

        for plot_name, view in self._views.items():
            rect = view.sceneBoundingRect()

            if rect.contains(pos):
                mouse_point = view.mapSceneToView(pos)
                self._x = to_int(mouse_point.x())
                self._y = mouse_point.y()
                self._plot_name = plot_name
                break

        # Then update cursor component
        self._update_line()
        self._update_label()
        self.update_info()

    def _update_line(self) -> None:
        """"""
        for v_line in self._v_lines.values():
            v_line.setPos(self._x)
            v_line.show()

        for plot_name, h_line in self._h_lines.items():
            if plot_name == self._plot_name:
                h_line.setPos(self._y)
                h_line.show()
            else:
                h_line.hide()

    def _update_label(self) -> None:
        """"""
        bottom_plot = list(self._plots.values())[-1]
        axis_width = bottom_plot.getAxis("right").width()
        axis_height = bottom_plot.getAxis("bottom").height()
        axis_offset = QtCore.QPointF(axis_width, axis_height)

        bottom_view = list(self._views.values())[-1]
        bottom_right = bottom_view.mapSceneToView(
            bottom_view.sceneBoundingRect().bottomRight() - axis_offset
        )

        for plot_name, label in self._y_labels.items():
            if plot_name == self._plot_name:
                label.setText(str(self._y))
                label.show()
                label.setPos(bottom_right.x(), self._y)
            else:
                label.hide()

        dt = self._manager.get_datetime(self._x)
        if dt:
            self._x_label.setText(dt.strftime("%Y-%m-%d %H:%M:%S"))
            self._x_label.show()
            self._x_label.setPos(self._x, bottom_right.y())
            self._x_label.setAnchor((0, 0))

    def update_info(self) -> None:
        """"""
        buf = {}

        for item, plot in self._item_plot_map.items():
            item_info_text = item.get_info_text(self._x)

            if plot not in buf:
                buf[plot] = item_info_text
            else:
                if item_info_text:
                    buf[plot] += ("\n\n" + item_info_text)

        for plot_name, plot in self._plots.items():
            plot_info_text = buf[plot]
            info = self._infos[plot_name]
            info.setText(plot_info_text)
            info.show()

            view = self._views[plot_name]
            top_left = view.mapSceneToView(view.sceneBoundingRect().topLeft())
            info.setPos(top_left)

    def move_right(self) -> None:
        """
        Move cursor index to right by 1.
        """
        if self._x == self._manager.get_count() - 1:
            return
        self._x += 1

        self._update_after_move()

    def move_left(self) -> None:
        """
        Move cursor index to left by 1.
        """
        if self._x == 0:
            return
        self._x -= 1

        self._update_after_move()

    def _update_after_move(self) -> None:
        """
        Update cursor after moved by left/right.
        """
        bar = self._manager.get_bar(self._x)
        self._y = bar.close_price

        self._update_line()
        self._update_label()

    def clear_all(self) -> None:
        """
        Clear all data.
        """
        self._x = 0
        self._y = 0
        self._plot_name = ""

        for line in list(self._v_lines.values()) + list(self._h_lines.values()):
            line.hide()

        for label in list(self._y_labels.values()) + [self._x_label]:
            label.hide()
