#!/bin/bash

# Copyright 2013 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# Produce metrics analyzing the output of a stress test

set -e

error() {
  echo "error: ${@}" >&2
}

# Given a token, search for and count the instances of lines from the
# logfile that start with the token.
count_result() {
  if [ ! -z "${1}" ]; then
    echo $(cat "${log}" | grep "^${1} " | wc -l)    
  else
    echo 0
  fi
}

main() {
  if [ $# -lt 1 ]; then
    cat <<EOF

USAGE: $(basename ${0}) logfile

Analyze the logfile of a stress test and produce metrics.

EOF
    exit 1
  fi

  local log="${1}"
  if [ ! -f "${log}" ]; then
    error "\"${log}\" not found"
    exit 1
  fi

  cat <<EOF
$(count_result "PASS_COURGETTE") successful courgette patches
$(count_result "FAIL_COURGETTE") failed courgette patches
$(count_result "FAIL_DISASSEMBLE") failed to disassemble/assemble
$(count_result "PASS_BSDIFF") succesful bsdiff patches
$(count_result "FAIL_BSDIFF") failed bsdiff patches
$(count_result "BEST_COURGETTE") patch(es) where courgette is smaller
$(count_result "BEST_BSDIFF") patch(es) where bsdiff is smaller
$(count_result "BEST_TIE") patch(es) where both are the same size
EOF

  # Log file has the format "^SIZE courgette=... bsdiff=..."
  local courgette_total="$(cat "${log}" \
    | grep "^SIZE " \
    | cut -d' ' -f2 \
    | awk -F= 'BEGIN{sum=0} {sum += $2} END{print sum}')"
  echo "${courgette_total} bytes for a courgette payload"

  local bsdiff_total="$(cat "${log}" \
    | grep "^SIZE " \
    | cut -d' ' -f3 \
    | awk -F= 'BEGIN{sum=0} {sum += $2} END{print sum}')"
  echo "${bsdiff_total} bytes for a bsdiff payload"

  local best_total="$(cat "${log}" \
    | grep "^BEST_" \
    | awk 'BEGIN{sum=0} {sum += $2} END{print sum}')"
    echo "${best_total} bytes for a best-choice payload"

  local pct="$(echo "100*${best_total}/${bsdiff_total}" \
    | bc -lq \
    | awk '{printf "%.2f\n", $0}')"
    echo "${pct}% of a bsdiff-only payload"

  local savings="$((bsdiff_total - best_total))"
  echo "${savings} bytes saved by courgette"

  local pct_savings="$(echo "100*${savings}/${bsdiff_total}" \
    | bc -lq \
    | awk '{printf "%.2f\n", $0}')"
  echo "${pct_savings}% savings"
}

main "${@}"