from typing import Optional

import pandas as pd
from PyQt5.QtWidgets import QWidget, QVBoxLayout
import pyqtgraph as pg
import numpy as np

from base.base import BasePlotWidget


class PlotWidget(BasePlotWidget):

    def _create_stage_region(self,
                             stage: str,
                             times: pd.Series,
                             dataframe: pd.DataFrame) -> Optional[pg.LinearRegionItem]:
        stage_diff = np.diff(dataframe[stage])
        start_index = np.where(stage_diff == 1)[0]
        finish_index = np.where(stage_diff == -1)[0]
        if start_index:
            start_timestamp = times[start_index[0]]
            finish_timestamp = times[finish_index[0]] if finish_index else times[len(times) - 1]
            region = pg.LinearRegionItem([start_timestamp, finish_timestamp], movable=False)
            region.setBrush(pg.mkBrush(self._stage_colors[stage]))
            return region
        return None

    def _build_widget(self, dataframe: pd.DataFrame) -> QWidget:
        widget = QWidget()
        layout = QVBoxLayout()

        time_axis = dataframe["time"]
        dataframe_headers = dataframe.columns.tolist()

        for channel, description in self._plt_channels.items():
            plot_widget = pg.PlotWidget(title=channel)
            plot_widget.showGrid(x=True, y=True)
            legend = pg.LegendItem((80, 60), offset=(70, 20))
            legend.setParentItem(plot_widget.graphicsItem())
            settings = description["Settings"]

            if settings["stages"] and all([stage in dataframe_headers for stage in self._stages]):
                for stage in self._stages:
                    region = self._create_stage_region(stage, time_axis, dataframe)
                    if region:
                        plot_widget.addItem(region)

            for signal in description["Signals"]:
                if signal["name"] in dataframe_headers:
                    plot = plot_widget.plot(time_axis, dataframe[signal["name"]], pen=signal["pen"])
                    legend.addItem(plot, signal["name"])
                    if settings["zoom"] and max(time_axis) < 5.0:
                        max_value = max(dataframe[signal["name"]])
                        plot_widget.setYRange(max_value - 200, max_value)
                        plot_widget.setInteractive(False)

            layout.addWidget(plot_widget)

        widget.setLayout(layout)
        return widget

    def build(self, data: list[pd.DataFrame]) -> None:
        widgets = [self._build_widget(data_sample) for data_sample in data]
        self._mediator.notify(self, widgets)