#!/usr/bin/env python3

# 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

cells_dir = "/sys/devices/jailhouse/cells/"
cell_dir  = cells_dir + "%d/"
stats_dir = cell_dir + "statistics/"


def main(stdscr, cell_id, cell_name, stats_names, cpus):
    def reset_stats():
        curses.halfdelay(10)
        return dict.fromkeys(stats_names, None)

    try:
        curses.use_default_colors()
        curses.curs_set(0)
    except curses.error:
        pass
    curses.noecho()
    value = dict.fromkeys(stats_names)
    old_value = reset_stats()
    cpu = -1
    while True:
        now = datetime.datetime.now()

        for name in stats_names:
            cpu_dir = ("/cpu%d" % cpus[cpu]) if cpu >= 0 else ""
            f = open((stats_dir + cpu_dir + "/%s") % (cell_id, 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_name)
        (height, width) = stdscr.getmaxyx()
        stdscr.hline(2, 0, " ", width, curses.A_REVERSE)
        stdscr.addstr(2, 0, "COUNTER ", curses.A_REVERSE)
        if cpu >= 0:
            stdscr.addstr(2, 8, "(CPU %d)" % cpus[cpu], curses.A_REVERSE)
        else:
            stdscr.addstr(2, 8, "(All CPUs)", 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 | C - Toggle CPU | A - All CPUs",
                      curses.A_REVERSE)
        stdscr.refresh()

        last_refresh = now

        try:
            c = stdscr.getch()
            if c == ord('q'):
                break
            elif c == ord('c'):
                old_value = reset_stats()
                cpu = (cpu + 1) % len(cpus)
            elif c == ord('a'):
                old_value = reset_stats()
                cpu = -1
            else:
                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)

cell_id = -1
try:
    if use_name:
        cell_name = sys.argv[2]
    else:
        cell_name = sys.argv[1]
        try:
            cell_id = int(sys.argv[1])
            with open((cell_dir + "name") % cell_id, "r") as f:
                cell_name = f.read().rstrip()
        except ValueError:
            pass

    if cell_id == -1:
        for id in os.listdir(cells_dir):
            f = open((cell_dir + "name") % int(id), "r")
            if f.read().rstrip() == cell_name:
                cell_id = int(id)
                break

    entries = os.listdir(stats_dir % cell_id)
    stats_names = [d for d in entries if d.startswith("vmexits_")]
    cpus = sorted([int(d[3:]) for d in entries if d.startswith("cpu")])
except OSError as e:
    print("reading stats: %s" % e.strerror, file=sys.stderr)
    exit(1)

curses.wrapper(main, cell_id, cell_name, stats_names, cpus)
