#!/usr/bin/env python
# Plot the changes in /proc/interrupts over time
# Date: 2014-06-17
# Author: Peter Wu <peter@lekensteyn.nl>

# Wishlist:
# Thicker legend lines
# Nicier smoothing

import matplotlib.pyplot as plt
import matplotlib
from collections import deque, OrderedDict
import numpy as np
from scipy.interpolate import spline, interp1d
import threading

# Number of seconds to show in the graph
XRANGE = 60
# Delay between updating the graph
INTERVAL = .5
# Log scale base or 0 to disable logarithmic y scaling
LOG_SCALE_BASE = 10
# Whether to enable smooth curves or not
SMOOTH_CURVES = True

MARKER_DEFAULT = 'o'
MARKER_SELECTED = 'v'

# 26 colors from http://graphicdesign.stackexchange.com/a/3815
# "A Colour Alphabet and the Limits of Colour Coding"
COLORS = ['#F0A3FF', '#0075DC', '#993F00', '#4C005C', '#191919', '#005C31',
'#2BCE48', '#FFCC99', '#808080', '#94FFB5', '#8F7C00', '#9DCC00', '#C20088',
'#003380', '#FFA405', '#FFA8BB', '#426600', '#FF0010', '#5EF1F2', '#00998F',
'#E0FF66', '#740AFF', '#990000', '#FFFF80', '#FFFF00', '#FF5005']
# From alex440's comment (currently not used)
ALT_COLORS = ['#023FA5', '#7D87B9', '#BEC1D4', '#D6BCC0', '#BB7784', '#FFFFFF',
'#4A6FE3', '#8595E1', '#B5BBE3', '#E6AFB9', '#E07B91', '#D33F6A', '#11C638',
'#8DD593', '#C6DEC7', '#EAD3C6', '#F0B98D', '#EF9708', '#0FCFC0', '#9CDED6',
'#D5EAE7', '#F3E1EB', '#F6C4E1', '#F79CD4']


def is_line_ok(name, yvalues):
    """Returns True if a line should be displayed for this name."""
    if max(yvalues) < 5:
        return False

    names_ok = ['hci', 'timer']
    for name_ok_part in names_ok:
        if name_ok_part in name:
            return True

    # Accept all
    return True

# Fix Unicode font
matplotlib.rc('font', family='DejaVu Sans')

# From http://stackoverflow.com/a/490090
def synchronized(lock):
    """Synchronization decorator."""
    def wrap(f):
        def newFunction(*args, **kw):
            with lock:
                return f(*args, **kw)
        return newFunction
    return wrap

def get_numbers():
    # TODO: may break the graph if a line disappears
    with open('/proc/interrupts') as pi:
        ncpus = len(pi.readline().split())
        for line in pi:
            name, values = line.split(':', 1)
            name = name.strip()
            values = values.strip().split(None, ncpus)
            if len(values) >= ncpus:
                # Name is ID + description for uniqueness
                name += ':' + values[-1];
                yield name, sum(int(values[i]) for i in range(0, ncpus))

prev = OrderedDict()
def get_diffs():
    for name, n in get_numbers():
        if name in prev:
            yield name, n - prev[name]
        else:
            yield name, 0
        prev[name] = n

plt.ylabel(u'\u0394interrupts')
plt.xlabel(u'time (sec)')
plt.grid('on')
#plt.ion() # Not necessary if show() does not block.
plt.show(block=False)
if LOG_SCALE_BASE > 0:
    plt.yscale('log', nonposy='clip', basey=LOG_SCALE_BASE)

# Used when picking a new line or in update()
update_legend = False
### BEGIN EVENTS

# After pressing ^W, stop the main loop
running = True
def on_close(event):
    global running
    running = False
plt.connect('close_event', on_close)

# Space toggles updating
paused = False
def on_keypress(event):
    global paused
    if event.key == ' ':
        paused = not paused
    update_title()
plt.connect('key_press_event', on_keypress)

last_selected = None
def select_line(line):
    global last_selected
    line = lines[line.get_label()]
    if last_selected:
        last_selected.set_marker(MARKER_DEFAULT)
    if last_selected == line:
        last_selected = None
    else:
        line.set_marker(MARKER_SELECTED)
        last_selected = line

def on_pick(event):
    global update_legend
    artist = event.artist
    if isinstance(artist, matplotlib.lines.Line2D):
        select_line(artist)
        update_legend = True
        do_draw()
plt.connect('pick_event', on_pick)

### END EVENTS

names = [name for name, _ in get_diffs()]
yvalues = {}
x_count = int(XRANGE / INTERVAL)
# Initialize y values for each name
for name in names:
    ydata = deque([0] * x_count, x_count)
    yvalues[name] = ydata
lines = {}

def update_title():
    title = 'Figure'
    if paused:
        title += ' (paused - press Space to resume)'
    plt.gcf().canvas.set_window_title(title)

# Lock to avoid updating the UI while the data is being refreshed
data_lock = threading.Lock()
# Since yvalues gets filled on the tail, substract from start time
start_time = -XRANGE
@synchronized(data_lock)
def refresh_data():
    global start_time
    # Update data
    for name, n in get_diffs():
        yvalues[name].append(n)
    start_time += INTERVAL

smooth = {}
@synchronized(data_lock)
def update():
    """Reads new data and updates the line values."""
    global update_legend
    # Update lines
    for name, n in get_diffs():
        ys = yvalues[name]
        # Consider only strictly positive values
        ydata = [y for y in ys if y > 0]
        xdata = [start_time + i * INTERVAL for i, y in enumerate(ys) if y > 0]

        if ydata and is_line_ok(name, ys):
            # Data is significant, show it
            if name in lines:
                lines[name].set_data(xdata, ydata)
            else:
                color = COLORS[names.index(name) % len(COLORS)]
                lines[name], = plt.plot(xdata, ydata, MARKER_DEFAULT + '-',
                                        label=name,
                                        color=color)
                lines[name].set_picker(5) # Make selectable
                update_legend = True

            # Smooth curve
            ydata_len = len(ydata)
            if ydata_len > 3 and SMOOTH_CURVES:
                min_x = min(xdata)
                max_x = max(xdata)
                xnew = np.linspace(min_x, max_x, (1 + max_x - min_x) * 8)
                #ynew = spline(xdata, ydata, xnew)
                # quadratic and cubic splines give too much deviations
                ynew = interp1d(xdata, ydata, kind='slinear')(xnew)
                if not name in smooth:
                    smooth[name], = plt.plot(xnew, ynew, color=lines[name].get_color())
                    # Smooth line is shown, hide straight lines
                    lines[name].set_linestyle('')
                else:
                    smooth[name].set_data(xnew, ynew)
            elif name in smooth:
                smooth[name].remove()
                del smooth[name]
                # No smooth line is shown, fallback to straight lines
                lines[name].set_linestyle('-')
        elif name in lines:
            # Data is insignificant, remove previous line
            lines[name].remove()
            del lines[name]
            update_legend = True

    largest = 10
    for name in yvalues:
        ydata = yvalues[name]
        if is_line_ok(name, ydata):
            largest = max(largest, max(ydata))
    # Update iff graph becomes too large
    #ymin, ymax = plt.ylim()
    #if ymax - ymin < largest:
    #    plt.ylim(ymin, ymin + largest)
    plt.ylim(0, largest)

    min_x = max(start_time, 0)
    plt.xlim(min_x, min_x + XRANGE)

def do_draw():
    """Actually draw the graph, updating the legend if necessary."""
    global update_legend
    # update legend if a line gets added, changed or removed
    if update_legend:
        old_legend = plt.axes().get_legend()
        if old_legend:
            # Undocumented API, use it to remember legend position
            old_loc = old_legend._get_loc()

        legend = plt.legend(loc='upper left',
                            framealpha=.5,
                            fontsize='small')
        legend.draggable()
        if old_legend:
            legend._set_loc(old_loc)

        # Enable selecting a line by clicking in the legend
        for line in legend.get_lines():
            line.set_picker(5)

        update_legend = False

    plt.draw()

update_title()

# Separate worker for fetching data
def refresh_data_timer():
    global t
    t = threading.Timer(INTERVAL, refresh_data_timer)
    t.start()
    refresh_data()
refresh_data_timer()

while running:
    if not paused:
        update()
    do_draw()
    plt.pause(INTERVAL)

# Cancel any scheduled timer
t.cancel()