#!/bin/sh
# Copyright 2012 The ChromiumOS Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# This isn't the exact copy that will be used in production, but it's better
# than pointing shellcheck at /dev/null.
# shellcheck source=../../scripts/lib/shflags/shflags
. /usr/share/misc/shflags || exit 1

DEFINE_string directory /run/bootstat "Bootstat archive directory" d

FLAGS "$@" || exit 1
eval set -- "${FLAGS_ARGV}"

NCPU="$(grep -c '^processor' /proc/cpuinfo)"
readonly NCPU

# shellcheck disable=SC2016 # We want a literal awk script.
SUMMARIZE_TIME='
  BEGIN {
    printf "%8s %4s %8s %4s  %s\n", "time", "%cpu", "dt", "%dt", "event"
  }

  {
    # input lines are like this:
    #  $1 = time since boot
    #  $2 = idle time since boot (normalized for NCPU)
    #  $3 = event name
    # input lines are sorted by $1
    uptime = $1 ; idle = $2
    cum_util = (200 * (uptime - idle) / uptime + 1) / 2
    delta = uptime - prev
    if (delta != 0) {
      util = (200 * (delta - idle + prev_idle) / delta + 1) / 2
    } else {
      util = 100
    }
    printf "%8d %3d%% %8d %3d%%  %s\n", uptime, cum_util, delta, util, $3
    prev = uptime ; prev_idle = idle
  }
'

# If there are no arguments on the command line, summarize all the
# events.  If there are arguments, summarize only the named events.
if [ $# -eq 0 ]; then
  set -- "${FLAGS_directory}/uptime-"*
else
  max=$#
  i=0
  while [ $((i += 1)) -le "${max}" ]; do
    set -- "$@" "${FLAGS_directory}/uptime-$1"
    shift
  done
fi

max=$#
i=0
# Catch some basic errors so awk doesn't choke.
while [ $((i += 1)) -le "${max}" ]; do
  if [ -r "$1" ]; then
    set -- "$@" "$1"
  else
    echo "Error: file $1 is not readable" 1>&2
  fi
  shift
done

# Pipeline explained:
#  1st awk program: print times as milliseconds and normalize idle time
#     by NCPU.
#  sort: sort the events by the uptime timestamp.
#  sed: remove '/run/bootstat/uptime-' from the event name.
#  2nd awk program:  produce the summarized output
awk 'BEGIN{OFMT="%f"}
     {print 1000*$1, 1000*$2/'"${NCPU}"', FILENAME}' "$@" |
  sort -k 1n | sed 's=[^ ]*uptime-==' | awk "${SUMMARIZE_TIME}"