#!/usr/bin/python

# Jailhouse, a Linux-based partitioning hypervisor
#
# Copyright (c) Siemens AG, 2014
#
# Authors:
#  Jan Kiszka <jan.kiszka@siemens.com>
#
# This work is licensed under the terms of the GNU GPL, version 2.  See
# the COPYING file in the top-level directory.

from __future__ import print_function
import curses
import datetime
import os
import sys

stats_dir = "/sys/devices/jailhouse/cells/%s/statistics"


def main(stdscr, cell, stats_names):
    curses.use_default_colors()
    curses.noecho()
    curses.curs_set(0)
    curses.halfdelay(10)
    value = dict.fromkeys(stats_names)
    old_value = dict.fromkeys(stats_names, None)
    while True:
        now = datetime.datetime.now()

        for name in stats_names:
            f = open((stats_dir + "/%s") % (cell, name), "r")
            value[name] = int(f.read())

        def sortkey(name):
            if old_value[name] is None:
                return (-value[name], name)
            else:
                return (old_value[name] - value[name], -value[name], name)

        stdscr.erase()
        stdscr.addstr(0, 0, "Statistics for %s cell" % cell)
        (height, width) = stdscr.getmaxyx()
        stdscr.hline(2, 0, " ", width, curses.A_REVERSE)
        stdscr.addstr(2, 0, "COUNTER", curses.A_REVERSE)
        stdscr.addstr(2, 30, "%10s" % "SUM", curses.A_REVERSE)
        stdscr.addstr(2, 40, "%10s" % "PER SEC", curses.A_REVERSE)
        line = 3
        for name in sorted(stats_names, key=sortkey):
            stdscr.addstr(line, 0, name)
            stdscr.addstr(line, 30, "%10u" % value[name])
            if not old_value[name] is None:
                dt = (now - last_refresh).total_seconds()
                delta_per_sec = (value[name] - old_value[name]) / dt
                stdscr.addstr(line, 40, "%10u" % round(delta_per_sec))
            old_value[name] = value[name]
            line += 1
        stdscr.hline(height - 1, 0, " ", width, curses.A_REVERSE)
        stdscr.addstr(height - 1, 1, "Q - Quit", curses.A_REVERSE)
        stdscr.refresh()

        last_refresh = now

        try:
            if stdscr.getch() == ord('q'):
                break
            curses.halfdelay(40)
        except KeyboardInterrupt:
            break
        except curses.error:
            continue


def usage(exit_code):
    prog = os.path.basename(sys.argv[0]).replace('-', ' ')
    print("usage: %s { ID | [--name] NAME }" % prog)
    exit(exit_code)


argc = len(sys.argv)
use_name = argc >= 2 and sys.argv[1] == "--name"

if argc < 2 or argc > 3 or (not use_name and argc > 2):
    usage(1)
if sys.argv[1] in ("--help", "-h"):
    usage(0)

try:
    if use_name:
        cell_name = sys.argv[2]
    else:
        cell_name = sys.argv[1]
        try:
            cell_id = int(sys.argv[1])
            for cell in os.listdir("/sys/devices/jailhouse/cells"):
                f = open("/sys/devices/jailhouse/cells/%s/id" % cell, "r")
                if int(f.read()) == cell_id:
                    cell_name = cell
                    break
        except ValueError:
            pass

    stats_names = os.listdir(stats_dir % cell_name)
except OSError as e:
    print("reading stats: %s" % e.strerror, file=sys.stderr)
    exit(1)

curses.wrapper(main, cell_name, stats_names)