#!/bin/sh

# A tester for extfs helpers.
#
# Copyright (C) 2016-2017
# The Free Software Foundation, Inc.
#
# This file is part of the Midnight Commander.
#
# The Midnight Commander is free software: you can redistribute it
# and/or modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation, either version 3 of the License,
# or (at your option) any later version.
#
# The Midnight Commander is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

help() {
  cat << EOS

NAME

$(basename "$0") - Tests the 'list' command of extfs helpers.

SYNOPSIS

  $(basename "$0") \\
     --data-dir /path/to/where/data/files/are/stored \\
     --helpers-dir /path/to/where/helpers/are/stored \\
     --data-build-dir /path/to/where/config.sh/is/stored

(But you're more likely to invoke this program with the 'run' script
created by 'make check'; or by 'make check' itself.)

DESCRIPTION

This program tests extfs helpers by feeding them input and comparing
their output to the expected output.

See README for full details.

You need to tell this program primarily two things: where the helpers are
stored, and where the "data files" are stored. The data files are *.input
files that are fed to the helpers and *.output files that are the correct
output expected from these helpers.

You also need to tell this program where the build flavor of the "data
files" is stored. Most notably this is where the 'config.sh' file is
created during build time. You do this with '--data-build-dir'.

EOS
}

#"'

#
# Some helpers use the 'sort' utility. The "expected output" files we
# provide must be generated in the same locale these helpers are to be run
# by the tester or else 'sort' will produce a different output than ours,
# failing the tests.
#
# We settle on the C locale.
#
LC_ALL=C
export LC_ALL

############################ Global variables ##############################

# The directories used.
data_dir=
data_build_dir=
helpers_dir1=
helpers_dir2=

opt_create_output=no        # "yes" if '--create-output' provided.
opt_run_mcdiff_on_error=no  # "yes" if '--mcdiff' provided.

############################ Coding guidance ###############################

#
# Portability notes:
#
# - We do `local var="$whatever"` instead of `local var=$whatever` for
#   compatibility with Dash. See http://unix.stackexchange.com/questions/97560.
#
# - The 'local' keyword used in this file isn't mandatory. Feel free to
#   remove it if it isn't supported by your archaic shell.
#

############################ Utility functions #############################

#
# Does $1 contain $2?
#
# Accepts basic regex.
#
has_string() {
  local haystack="$1"  # quotes needed for Dash, as may contain spaces (see notes above).
  local needle="$2"
  echo "$haystack" | grep "$needle" > /dev/null
}

#
# Given "/path/to/basename.and.some.ext", returns "basename"
#
basename_sans_extensions() {
  local base="$(basename "$1")"
  echo "${base%%.*}"
}

#
# Does an executable exist?
#
has_prog() {
  # see http://stackoverflow.com/questions/592620
  command -v "$1" >/dev/null 2>&1
}

#
# Are we running interactively? Or is our output redirected to a file/pipe?
#
is_interactive() {
  [ -t 1 ]
}

#
# Can we use colors?
#
has_colors() {
  is_interactive && has_string "$TERM" 'linux\|xterm\|screen\|tmux\|putty'
}

init_colors() {
  if has_colors; then
    local esc="$(printf '\033')"  # for portability
    C_bold="$esc[1m"
    C_green="$esc[1;32m"
    C_red="$esc[1;31m"
    C_magenta="$esc[1;35m"
    C_norm="$esc[0m"
  fi
}

#
# A few colorful alternatives to 'echo'.
#
header()  { echo $C_bold"$@"$C_norm; }
err()     { echo $C_red"$@"$C_norm; }
notice()  { echo $C_magenta"$@"$C_norm; }
success() { echo $C_green"$@"$C_norm; }

die() {
  err "Error: $@"
  exit 1
}

assert_dir_exists() {
  [ -d "$1" ] || die "The directory '$1' doesn't exist, or is not a directory."
}

#
# Creates a temporary file.
#
temp_file() {
  local template="$1"
  # BSD's doesn't support -t.
  mktemp "${TMPDIR:-/tmp}/$template"
}

################################ Main code #################################

#
# Prints out the command to run a helper, if it can find it.
#
# For example,
#
#    find_helper uzip /path/to/helpers/dir
#
# prints:
#
#    /usr/bin/perl -w /path/to/helpers/dir/uzip
#
# Since helpers in the build tree don't yet have executable bit set, we
# need to extract the shebang line.
#
find_helper() {
  local helper_name="$1"
  local dir="$2"

  local try="$dir/$helper_name"
  if [ -f "$try" ]; then
    helper_CMD="$(head -1 $try | cut -c 3-) $try"  # reason #1 we don't allow spaces in pathnames.
    true
  else
    false
  fi
}

#
# Returns the path of 'config.sh'.
#
path_of_config_sh() {
  echo "$data_build_dir/config.sh"
}

#
# Export variables to be used by tests.
#
# See README for their documentation.
#
export_useful_variables() {
  local input="$1"

  # Frequently used variables:
  MC_TEST_EXTFS_LIST_CMD="mc_xcat $input"  # reason #2 we don't allow spaces in pathnames.
  export MC_TEST_EXTFS_LIST_CMD

  # Infrequently used variables:
  MC_TEST_EXTFS_INPUT=$input
  export MC_TEST_EXTFS_INPUT
  MC_TEST_EXTFS_DATA_DIR=$data_dir
  export MC_TEST_EXTFS_DATA_DIR
  MC_TEST_EXTFS_DATA_BUILD_DIR=$data_build_dir
  export MC_TEST_EXTFS_DATA_BUILD_DIR
  MC_TEST_EXTFS_CONFIG_SH=$(path_of_config_sh)
  export MC_TEST_EXTFS_CONFIG_SH
}

#
# The crux of this program.
#
run() {

  local error_count=0
  local pass_count=0

  for input in "$data_dir"/*.input; do

    has_string "$input" '\*' && break  # we can't use 'shopt -s nullglob' as it's bash-specific.

    header "Testing $input"

    has_string "$input" " " && die "Error: filename contains spaces."

    #
    # Set up variables:
    #

    local helper_name="$(basename_sans_extensions "$input")"
    local expected_parsed_output="${input%.input}.output"
    local env_vars_file="${input%.input}.env_vars"
    local args_file="${input%.input}.args"

    local do_create_output=no

    if [ ! -f "$expected_parsed_output" ]; then
      # Corresponding *.output file doesn't exist. We either create it, later, or exit with error.
      if [ $opt_create_output = "yes" ]; then
        do_create_output=yes
      else
        err
        err "Missing file: '$expected_parsed_output'."
        err "You have to create an '.output' file for each '.input' one."
        err
        notice "Tip: invoke this program with '--create-output' to"
        notice "automatically create missing '.output' files."
        notice
        exit 1
      fi
    fi

    find_helper "$helper_name" "$helpers_dir1" ||
      find_helper "$helper_name" "$helpers_dir2" ||
        die "I can't find helper '$helper_name' in either $helpers_dir1 or $helpers_dir2"

    local extra_parser_args=""
    [ -f "$args_file" ] && extra_parser_args="$(cat "$args_file")"

    local actual_output="$(temp_file $helper_name.actual-output.XXXXXXXX)"
    local actual_parsed_output="$(temp_file $helper_name.actual-parsed-output.XXXXXXXX)"

    #
    # Variables are all set. Now do the actual stuff:
    #

    (
    export_useful_variables "$input"
    if [ -f "$env_vars_file" ]; then
      set -a  # "allexport: Export all variables assigned to."
      . "$env_vars_file"
      set +a
    fi
    $helper_CMD list /dev/null > "$actual_output"
    )

    error_count=$((error_count + 1))  # we'll decrement it later.

    if [ ! -s "$actual_output" ]; then
      err
      err "The helper '$helper_name' produced no output for this input. Something is wrong."
      err
      err "Make sure this helper supports testability: that it uses \$MC_TEST_EXTFS_LIST_CMD."
      err
      err "You may try running the helper yourself with:"
      err
      err "  \$ MC_TEST_EXTFS_LIST_CMD=\"mc_xcat $input\" \\"
      err "      $helper_CMD list /dev/null"
      err
      continue
    fi

    # '--symbolic-ids': uid/gid aren't portable between computers,
    # of course, so we always represent them symbolically when possible.
    if ! mc_parse_ls_l --symbolic-ids $extra_parser_args "$actual_output" > "$actual_parsed_output"; then
      err
      err "ERROR: Parsing of the output of the helper '$helper_name' has failed."
      err "This means that $helper_name has produced output that MC won't be able to parse."
      err "Run the parsing command yourself ('mc_parse_ls_l $extra_parser_args $actual_output')"
      err "to figure out the problem."
      err
      continue
    fi

    if [ $do_create_output = "yes" ]; then
      # We arrive here if we were invoked with '--create-output' and
      # the .output file doesn't exist. We create it and move to the next iteration.
      cp "$actual_parsed_output" "$expected_parsed_output"
      notice "The output file has been created in $expected_parsed_output"
      continue
    fi

    if ! cmp "$expected_parsed_output" "$actual_parsed_output"; then
      err
      err "ERROR: $helper_name has produced output that's different than the expected output."
      err
      err "  Expected output (after parsing): $expected_parsed_output"
      err "  Actual output (after parsing): $actual_parsed_output"
      err
      err "This might mean that a bug was introduced into $helper_name. Or that a bug was fixed."
      err "Please compare the files."
      err
      err "If the actual output is the correct one, just copy the latter file"
      err "onto the former (and commit to the git repository)."
      err
      if is_interactive; then
        if [ $opt_run_mcdiff_on_error = "yes" ]; then
          notice "Hit ENTER to launch mcdiff ..."
          read dummy_var  # dash needs this.
          ${MCDIFF:-mcdiff} "$expected_parsed_output" "$actual_parsed_output"
        else
          notice "Tip: invoke this program with '--mcdiff' to automatically launch"
          notice "mcdiff to visually inspect the diff."
          notice
          notice "(Running this program non-interactively (i.e., redirecting the"
          notice "output to a file or pipe) automatically adds diff to the output.)"
          notice
        fi
      else
        err "------------ diff of the expected output vs the actual output: -------------"
        diff -U2 "$expected_parsed_output" "$actual_parsed_output"
        err "------------------------------- end of diff --------------------------------"
      fi
      continue
    fi

    rm "$actual_output" "$actual_parsed_output"

    error_count=$((error_count - 1))  # cancel the earlier "+1".
    pass_count=$((pass_count + 1))

    success "PASSED."

  done

  [ $pass_count = "0" -a $error_count = "0" ] && notice "Note: The data directory contains no *.input files."

  [ $error_count = "0" ]  # exit status of function.
}

parse_command_line_arguments() {
  # We want --long-options, so we don't use 'getopts'.
  while [ -n "$1" ]; do
    case "$1" in
      --data-dir)
        data_dir=$2
        shift 2
        ;;
      --data-build-dir)
        data_build_dir=$2
        shift 2
        ;;
      --helpers-dir)
        if [ -z "$helpers_dir1" ]; then
          helpers_dir1=$2
        else
          helpers_dir2=$2
        fi
        shift 2
        ;;
      --create-output)
        opt_create_output=yes
        shift
        ;;
      --mcdiff)
        opt_run_mcdiff_on_error=yes
        shift
        ;;
      --help|-h)
        help
        exit
        ;;
      *)
        die "Unknown command-line option $1"
        ;;
    esac
  done
}

#
# Check that everything is set up correctly.
#
verify_setup() {
  [ -n "$data_dir" ] || die "You didn't specify the data dir (--data-dir). Run me with --help for info."
  [ -n "$data_build_dir" ] || die "You didn't specify the data build dir (--data-build-dir). Run me with --help for info."
  [ -n "$helpers_dir1" ] || die "You didn't specify the helpers dir (--helpers-dir). Run me with --help for info."
  [ -z "$helpers_dir2" ] && helpers_dir2=$helpers_dir1  # we're being lazy.

  local dir
  for dir in "$data_dir" "$data_build_dir" "$helpers_dir1" "$helpers_dir2"; do
    assert_dir_exists "$dir"
    has_string "$dir" " " && die "$dir: Sorry, spaces aren't allowed in pathnames."  # search "reason", twice, above.
  done

  [ -e "$(path_of_config_sh)" ] || die "Missing file $(path_of_config_sh). You probably have a mistake in the '--data-build-dir' path."

  local missing_progs=""
  check_prog() {
    if ! has_prog "$1"; then
      err "I can't see the program '$1'."
      missing_progs="${missing_progs}${missing_progs:+ and }'$1'"
    fi
  }

  check_prog "mc_parse_ls_l"
  check_prog "mc_xcat"
  check_prog "mktemp"  # non-POSIX
  [ -z "$missing_progs" ] || die "You need to add to your PATH the directories containing the executables $missing_progs."
}

main() {
  init_colors
  parse_command_line_arguments "$@"
  verify_setup
  run  # being the last command executed, its exit status is that of this whole script.
}

main "$@"