from datetime import datetime, timedelta
import matplotlib
import matplotlib.pyplot as plt 
import matplotlib.dates as mdates

class Chart:
    def __init__(self, samples = 50, title = None, limits = None, batch=False, show=True, fullscreen=False, read_x=False):
        self.start = datetime.now()
        self.x = []
        self.y = []
        self.samples = samples
        self.fig = plt.figure()
        self.axis = self.fig.add_subplot(111, autoscale_on = True, xticklabels = [])
        
        scale_axis = "both" if not limits else "x"
        self.axis.autoscale(enable=True, axis=scale_axis, tight = 2)
        # save limits
        self.limits = limits
        self.title = title

        self.axis.set_label(title)
        self.fig.canvas.draw()
        self.draw_opts = 'r-'
        self.line = False

        # upate timeout code (limit to 10fps)
        self.last_update = datetime.min
        self.update_timeout = timedelta(seconds=0.1)

        self.read_x = read_x

        # if batch mode, do not use timestamp when read from stdin
        self.batch = batch
        self.fullscreen = fullscreen

        if show:
            plt.show(block=False)

    def ui_update(self, final_draw=False):
        if len(self.y) < 2:
            return

        if not final_draw and datetime.now() - self.last_update < self.update_timeout:
            return
        
        self.axis.clear()
        # call plot method that is easily overrideable
        self.plot()

        if self.limits:
            self.axis.set_ylim(self.limits)

        if not self.batch:
            self.axis.xaxis.set_major_formatter(mdates.DateFormatter("%H:%M:%S"))
            self.fig.autofmt_xdate()


        if self.fullscreen:
            plt.subplots_adjust(left=0, bottom=0, right=1, top=1, wspace=0, hspace=0)
        else:
            plt.title(self.title)

        self.fig.canvas.draw()
        self.fig.canvas.flush_events()
        self.last_update = datetime.now()

    
    def plot(self):

        if self.batch:
            self.axis.plot(self.y, self.draw_opts)
        else:
            self.axis.plot_date(self.x, self.y, self.draw_opts)

    def read_input(self, input):
        self.y.append(float(input))
        self.x.append(datetime.now())

        if self.samples > 0 and len(self.y) > self.samples:
            self.y.pop(0)
            self.x.pop(0)
        
        self.ui_update()

    def save_to_file(self, file):
        self.ui_update(final_draw = True)
        plt.savefig(file)