plot_channels/plot_channels.py

""" Plot channels from BS (beam synchronous) or PV (EPICS) sources to the terminal. """

from typing import Tuple, Optional
from itertools import cycle, islice
import re
import time

from collections import deque
import click

import numpy as np

from bsread import dispatcher, source

import plotext as plt
import epics


def clean_name(fname):
    """Returns the filename with all special characters but / . _ - #
    replaced with an underscore.

    """
    cleaned_name = re.sub(r"[^a-zA-Z0-9\/\,\#\._-]", "_", fname)
    return cleaned_name


class ChannelData:
    """
    Collection of timestamps and values of a channel in a deque with a maximum length.
    Additionally allows to save the data (peridodically) to a file.

    Args:
        name (str): The name of the channel.
        save_file_prefix (str, optional): The prefix for the save file name. Defaults to None.
        window_length (int, optional): The maximum length of the data window. Defaults to 500.

    """

    def __init__(self, name: str, save_file_prefix=None, window_length=500):
        self.name = name
        self.window_length = window_length
        self._x, self._y = deque(), deque()
        self.save_file_prefix = save_file_prefix

        if self.save_file_prefix is not None:
            self.save = True
        else:
            self.save = False

        if self.save:
            self.x_save, self.y_save = deque(), deque()

            save_file_prefix = clean_name(save_file_prefix)
            self.save_fname = clean_name(f"{save_file_prefix}_{self.name}.dat")

            with open(self.save_fname, "w", encoding="utf-8") as f:
                header = f"timestamp {self.name}\n"
                f.write(header)

    @property
    def x(self):
        return np.array(self._x)

    @property
    def y(self):
        return np.array(self._y)

    def append(self, x, y):
        """
        Append a new data point to the channel.

        Args:
            x: The x value.
            y: The y value.

        """
        self._x.append(x)
        self._y.append(y)

        if len(self._x) > self.window_length:
            self._x.popleft()
            self._y.popleft()

        if self.save:
            self.x_save.append(x)
            self.y_save.append(y)

    def trigger_save(self):
        """
        Trigger the save operation to save the data to a file.
        """
        if self.save:
            out = np.zeros((len(self.x_save), 2))
            out[:, 0] = self.x_save
            out[:, 1] = self.y_save

            self.x_save, self.y_save = deque(), deque()

            with open(self.save_fname, "a", encoding="utf-8") as f:
                np.savetxt(
                    f,
                    out,
                    fmt="%.14g",
                )

    def __str__(self) -> str:
        return f"Channel:{self.name}"

    def __repr__(self) -> str:
        return f"Channel({self.name})"


def yield_bs_data(channel_names: list[str]):
    """Yields BS data from the given channels with timestamp."""
    if len(channel_names) == 0:
        return None

    with source(channels=channel_names) as stream:
        while True:
            message = stream.receive()
            # messages contains:
            # pulse_id = message.data.pulse_id
            # global_timestamp = message.data.global_timestamp,
            #                    the global timestamp in seconds since 1970 for this pulse_id
            # global_timestamp_offset = message.data.global_timestamp_offset, the ns part of the timestamp?

            # channel_data = message.data.data['channel_name']
            # message.data.data['SINSB0-'].timestamp # timestamp of the IOC
            # message.data.data['SINSB0-'].timestamp_offset # timestamp offset (ns) of the IOC

            timestamp = message.data.global_timestamp + message.data.global_timestamp_offset / 1000_000_000
            channel_data = {"pulse_id": {"value": message.data.pulse_id, "timestamp": timestamp}}

            for key, value in message.data.data.items():
                channel_data[key] = {
                    "value": value.value,
                    "timestamp": value.timestamp + value.timestamp_offset / 1000_000_000,
                }

            yield channel_data


def yield_pv_data(channel_names: list[str]):
    """Yields PV data from the given channels with timestamp."""

    pvs = {channel: epics.PV(channel) for channel in channel_names}
    channel_data = {}

    while True:
        for channel, pv in pvs.items():
            data = pv.get_with_metadata()
            channel_data[channel] = {"value": data["value"], "timestamp": data["timestamp"]}

        yield channel_data


def roundrobin(*iterables):
    "Visit input iterables in a cycle until each is exhausted."
    # roundrobin('ABC', 'D', 'EF') → A D E B F C
    # Algorithm credited to George Sakkis, posted as recipe in itertools
    iterators = map(iter, iterables)
    for num_active in range(len(iterables), 0, -1):
        iterators = cycle(islice(iterators, num_active))
        yield from map(next, iterators)


def yield_data(channel_names: list, only_pv=False):
    """Obtains data as a generator from either BS or PV sources.
    Decides based on availability, uses BS data as default.

    Returns: channel_data as dict (e.g. channel_data[channel_name]['value', 'timestamp'])
    """
    bs_channels = dispatcher.get_current_channels()

    # separate into BS and PV channels

    if only_pv:
        pv_list = channel_names
        bs_list = []
    else:
        bs_list = [ch for ch in channel_names if ch in bs_channels]
        pv_list = [ch for ch in channel_names if ch not in bs_list]

    for channel_data in roundrobin(yield_bs_data(bs_list), yield_pv_data(pv_list)):
        yield channel_data


def collect_data(channels: dict):
    """Collects data from the given channels and yields the updated data dictionary."""

    # typical channel_data:
    # {'pulse_id': {'value': 21289615168, 'timestamp': 1717427820.5366151},
    #  'SINSB01-RLLE-DSP:PHASE-VS': {'value': -121.776505, 'timestamp': 1717418177.347}}

    channel_names = list(channels.keys())

    for update in yield_data(channel_names):
        for name, entry in update.items():
            channels[name].append(entry["timestamp"], entry["value"])

        yield channels


def plot(channels, start_time=0, in_subplots=False, marker="hd"):
    """Plots channels on the console."""

    # plt.clf()
    plt.limit_size(False, False)
    plt.theme("pro")

    plt.xlabel("Timestamp")
    plt.ylabel("Value")

    num_channels = len(channels)

    if in_subplots:
        plt.subplots(num_channels, 1)
    plt.main().plot_size(plt.tw(), plt.th() - 1)
    plt.clear_data()

    for i, channel in enumerate(channels.values()):
        if in_subplots:
            plt.subplot(i + 1, 1)

        plt.plot(channel.x - start_time, channel.y, label=channel.name, marker=marker)

    plt.show()


def runner(
    channels: dict, acquire_interval=0.1, plot_interval=1, in_subplots=False, abort=False, relative_time=True
):
    """
    Loop for data collection and plotting.
    acquire_interval: interval in seconds for data acquisition (needs to be faster than 100 Hz,
                      e.g. smaller than 0.01 s to capture all BS data).
    """

    if relative_time:
        start_time = time.time()
    else:
        start_time = 0

    collector = collect_data(channels)  # initialize generator

    last_collect_time = time.time()
    last_plot_time = time.time()

    while not abort:
        now = time.time()
        elapsed_collect = now - last_collect_time
        elapsed_plot = now - last_plot_time

        if elapsed_collect > acquire_interval:
            channels = collector.send(None)
            last_collect_time = time.time()

        if elapsed_plot > plot_interval:  # default: 1 Hz plot updates and save interval
            plot(channels, in_subplots=in_subplots, start_time=start_time)

            for channel in channels.values():
                channel.trigger_save()

            last_plot_time = time.time()

        sleep_time = max(0, acquire_interval - elapsed_collect)

        time.sleep(sleep_time)  # should be faster than 100 Hz for BS data


@click.command()
@click.argument("channel_names", nargs=-1)
@click.option("--acquire-interval", default=0.1, help="Interval in seconds for data collection.")
@click.option("--plot-interval", default=1, help="Interval in seconds for plot update.")
@click.option("--save-prefix", default=None, help="Prefix for the save filenames.")
@click.option("--in-subplots", default=False, type=bool, help="Whether to plot in subplots.")
def main(
    channel_names: Tuple[str, ...],
    acquire_interval=0.1,
    plot_interval=1,
    save_prefix: Optional[str] = None,
    in_subplots=False,
):
    """ Plot channels from BS (beam synchronous) or PV (EPICS) sources. """
    channels = {channel: ChannelData(channel, save_file_prefix=save_prefix) for channel in channel_names}
    runner(channels, acquire_interval=float(acquire_interval), plot_interval=plot_interval, in_subplots=in_subplots)


if __name__ == "__main__":
    main()