#!/bin/bash
# Copyright 2017 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

function get_host_tools_dir {
  local -r build_dir="$(fx-build-dir-if-present && echo "${FUCHSIA_BUILD_DIR}")"
  local -r host_tools="${build_dir}/host-tools"
  if [[ -d "${build_dir}" && -d "${host_tools}"  ]]; then
    echo "${host_tools}"
  fi
}

function get_exec_from_metadata {
  local -r metadata_file=$1

  export PREBUILT_3P_DIR FUCHSIA_DIR HOST_PLATFORM
  export HOST_TOOLS_DIR="$(get_host_tools_dir)"

  awk -F ' *= *' -f - "${metadata_file}" <<'EOF'
    /^#### +EXECUTABLE */ {
      gsub(/\${PREBUILT_3P_DIR}/, ENVIRON["PREBUILT_3P_DIR"], $2);
      gsub(/\${FUCHSIA_DIR}/, ENVIRON["FUCHSIA_DIR"], $2);
      gsub(/\${HOST_TOOLS_DIR}/, ENVIRON["HOST_TOOLS_DIR"], $2);
      gsub(/\${HOST_PLATFORM}/, ENVIRON["HOST_PLATFORM"], $2);
      print $2;
    }
EOF
}

function _relative {
  cmd="$1"
  if [[ "${cmd}" == *"${fuchsia_dir}"* ]]; then
    echo "//${cmd#${fuchsia_dir}/}"
  else
    echo "${cmd}"
  fi
}

function find_executable {
  local cmd_name="$1"
  local cmd_path="$(commands "${cmd_name}")"
  cmd_path="${cmd_path%.fx}"
  local fx_file_path="${cmd_path}.fx"
  if [[ ! -f "${fx_file_path}" ]]; then
    # no metadata, so let's try to find the file
    if [[ -z "${cmd_path}" ]]; then
      # no file in regular script directories, look in host_tools
      cmd_path="$(find_host_tools "${cmd_name}")"
    fi
    echo "${cmd_path}"
    if [[ ! -x "${cmd_path}" ]]; then
      return 1
    fi

  else
    # there's metadata
    local from_metadata="$(get_exec_from_metadata "${fx_file_path}")"

    if [[ -n "${from_metadata}" ]]; then
      # EXECUTABLE is defined in the metadata, use it
      echo "${from_metadata}"
      if [[ -f "${cmd_path}"  && ! "${cmd_path}" -ef "${from_metadata}" ]]; then
        fx-error "Invalid ${fx_file_path}: if both ${basename_exec} and EXECUTABLE metadata exist, they must point to the same file"
        return 1
      fi
    else
      # no EXECUTABLE in the metadata, so return the cmd_path itself
      echo "${cmd_path}"
      if [[ ! -x "${cmd_path}" ]]; then
        return 1
      fi
    fi
  fi
}

function find_execs_and_metadata {
  local cmd_name=$1
  shift

  if [[ -z "${cmd_name}" ]]; then
    cmd_name="*"
  fi
  local dirs=()
  for d in "$@"; do
    if [[ -d "${d}" ]]; then
      dirs+=( "${d}" )
    fi
  done
  if [[ ${#dirs[@]} -eq 0 ]]; then
    return 0
  fi

  # run find assuming "-executable" is supported
  cmds="$( find "${dirs[@]}" -maxdepth 1 -type f \
    \( -executable -name "${cmd_name}" \) -o \
    \( -name "${cmd_name}.fx" \) 2>/dev/null )"

  if [[ $? -ne 0 ]]; then
    # assume that the error was caused because versions of find older than 4.3.0
    # don't support -executable. Run with -perm +100 instead, which is not
    # supported in versions of find newer than 4.5.12, so it can't be used always.
    cmds="$( find "${dirs[@]}" -maxdepth 1 -type f \
      \( -perm +100 -name "${cmd_name}" \) -o \
      \( -name "${cmd_name}.fx" \) 2>/dev/null )"
    if [[ $? -ne 0 ]]; then
      {
        echo "ERROR: 'find' failed unexpectedly, please execute fx with '-x' and report a bug."
        echo "At least one of the commands below was expected to work:"
        echo 'find ' "${dirs[@]}" '-maxdepth 1 -type f \( -executable -name' "\"${cmd_name}\"" '\) -o \( -name ' "\"${cmd_name}.fx\"" '\)'
        echo 'find ' "${dirs[@]}" '-maxdepth 1 -type f \( -perm +100 -name' "\"${cmd_name}\"" '\) -o \( -name ' "\"${cmd_name}.fx\"" '\)'
      } >&2
      exit 1
    fi
  fi
  sort -u <<< "${cmds}"
}


function find_host_tools {
  local cmd_name=$1
  local -r host_tools="$(get_host_tools_dir)"
  if [[ -z "${host_tools}" ]]; then
    return
  fi
  # get a list of non-host-tools commands and metadata files, separated by
  # semi-colon.
  cmds="$(commands | tr '\n' ';')"

  binaries=()
  # do not list a host tool if there's a subcommand script or an .fx metadata
  # file with the same name.
  for binary in $(find_execs_and_metadata "${cmd_name}" "${host_tools}"); do
    name="${binary##*/}"   # remove path, equivalent to basename but faster
    # only return the binary if no {binary} or {binary}.fx as other commands
    if [[ "${cmds}" != */${name}.fx\;* && "${cmds}" != */${name}\;* ]]; then
      binaries+=( "${binary}" )
    fi
  done
  echo "${binaries[@]}"
}


function commands {
  local cmd_name=$1
  local dirs
  # handle "fx help vendor VENDOR COMMAND"
  if [[ "${cmd_name}" == "vendor" && $# -eq 3 ]]; then
    vendor=$2
    cmd_name=$3
    dirs=("${fuchsia_dir}"/vendor/${vendor}/scripts/devshell)
  else
    dirs=("${fuchsia_dir}"/tools/devshell{,/contrib} "${fuchsia_dir}"/vendor/*/scripts/devshell)
  fi

  find_execs_and_metadata "${cmd_name}" "${dirs[@]}"
}


function help_options {
  cat <<END

fx help flags: fx help [OPTION]
  --no-contrib      Hide contrib commands (see //tools/devshell/README.md)
  --deprecated      Do not hide deprecated commands
END
}

function help_global_options {
  cat <<END

Global fx options: fx [OPTION] ${cmd} ...
  --dir=BUILD_DIR       Path to the build directory to use when running COMMAND.
  -d=DEVICE_NAME        Target a specific device. DEVICE_NAME may be a Fuchsia
                        device name. Note: "fx set-device" can be used to set a
                        default DEVICE_NAME for a BUILD_DIR.
  -i                    Iterative mode.  Repeat the command whenever a file is
                        modified under your Fuchsia directory, not including
                        out/.
  -x                    Print commands and their arguments as they are executed.
  -xx                   Print extra logging of the fx tool itself (implies -x)
END
}

function help_list_commands {
  local hide_contrib=0
  local show_deprecated=0
  while [[ $# -ne 0 ]]; do
    if [[ "$1" == "--deprecated" ]]; then
      show_deprecated=1
    elif [[ "$1" == "--no-contrib" ]]; then
      hide_contrib=1
    fi
    shift
  done

  # list all subcommands with summaries, grouped by categories
  commands | xargs awk \
    -v hide_contrib=${hide_contrib} \
    -v show_deprecated=${show_deprecated} \
    -f "${fuchsia_dir}/scripts/fx-help.awk"

  # list host tools build artifacts without corresponding metadata
  host_tools="$(find_host_tools)"
  if [[ -n "${host_tools}" ]]; then
    echo "Host binaries produced by the build with no metadata (more info at //tools/devshel/README.md):"
    for i in ${host_tools}; do
      echo -n "  "
      basename $i
    done
  fi

  help_options
  help_global_options
}

function help_command {
  local cmd="$@"
  local cmd_path="$(commands ${cmd} | head -1)"
  if [[ -z "${cmd_path}" ]]; then
    local cmd_path="$(find_host_tools ${cmd} | head -1)"
    if [[ -z "${cmd_path}" ]]; then
      echo "Command ${cmd} not found. Try \`fx help\`"
    else
      echo "'$(_relative "${cmd_path}")' is a host tool and no metadata" \
        "was found. Try running \`fx ${cmd} -h\`"
    fi
  elif [[ $(file -b --mime "${cmd_path}" | cut -d / -f 1) == "text" ]]; then
    fx-print-command-help "${cmd_path}"
    help_global_options
  else
    echo "No help found. Try \`fx ${cmd} -h\`"
  fi
}

function usage {
  cat <<END
usage: fx [--dir BUILD_DIR] [-d DEVICE_NAME] [-i] [-x] COMMAND [...]

Run Fuchsia development commands. Must be run either from a directory
that is contained in a Platform Source Tree or with the FUCHSIA_DIR
environment variable set to the root of a Platform Source Tree.

host shell extensions: (requires "source scripts/fx-env.sh")
  fx-update-path        add useful tools to the PATH
  fx-set-prompt         display the current configuration in the shell prompt

END

  help_list_commands "$@"
}

fuchsia_dir="${FUCHSIA_DIR}"
if [[ -z "${fuchsia_dir}" ]]; then
  # We walk the parent directories looking for .jiri_root rather than using
  # BASH_SOURCE so that we find the fuchsia_dir enclosing the current working
  # directory instead of the one containing this file in case the user has
  # multiple source trees and is picking up this file from another one.
  fuchsia_dir="$(pwd)"
  while [[ ! -d "${fuchsia_dir}/.jiri_root" ]]; do
    fuchsia_dir="$(dirname "${fuchsia_dir}")"
    if [[ "${fuchsia_dir}" == "/" ]]; then
      echo "Cannot find Platform Source Tree containing $(pwd)"
      exit 1
    fi
  done
fi

declare -r vars_sh="${fuchsia_dir}/tools/devshell/lib/vars.sh"
source "${vars_sh}" || exit $?

declare -r metrics_sh="${fuchsia_dir}/tools/devshell/lib/metrics.sh"
source "${metrics_sh}" || exit $?

while [[ $# -ne 0 ]]; do
  case $1 in
    --config=*|--dir=*|-d=*)
      # Turn --switch=value into --switch value.
      arg="$1"
      shift
      set -- "${arg%%=*}" "${arg#*=}" "$@"
      continue
      ;;
    --config)
      fx-warn "DEPRECATION NOTICE: --config is deprecated, use --dir instead."
      sleep 5
      if [[ $# -lt 2 ]]; then
        usage
        fx-error "Missing path to config file for --config argument"
        exit 1
      fi
      shift # Removes --config.
      export _FX_BUILD_DIR="$(source "$1"; echo "${FUCHSIA_BUILD_DIR}")"
      ;;
    --dir)
      if [[ $# -lt 2 ]]; then
        usage
        fx-error "Missing path to build directory for --dir argument"
        exit 1
      fi
      shift # Removes --dir.
      export _FX_BUILD_DIR="$1"
      if [[ "$_FX_BUILD_DIR" == //* ]]; then
        _FX_BUILD_DIR="${fuchsia_dir}/${_FX_BUILD_DIR#//}"
      fi
      ;;
    -d)
      if [[ $# -lt 2 ]]; then
        usage
        fx-error "Missing device name for -d argument"
        exit 1
      fi
      shift # removes -d
      export FUCHSIA_DEVICE_NAME="$1"
      ;;
    -i)
      declare iterative=1
      ;;
    -x)
      export FUCHSIA_DEVSHELL_VERBOSITY=1
      ;;
    -xx)
      set -x
      ;;
    --)
      shift
      break
      ;;
    help|--help)
      if [[ $# -lt 2 || "$2" =~ ^\-\-.* ]]; then
        shift
        usage "$@"
      else
        shift
        help_command "$@"
      fi
      exit 0
      ;;
    -*)
      usage
      fx-error "Unknown global argument $1"
      exit 1
      ;;
    *)
      break
      ;;
  esac
  shift
done

if [[ $# -lt 1 ]]; then
  usage
  fx-error "Missing command name"
  exit 1
fi

command_name="$1"
command_path="$(find_executable ${command_name})"

if [[ $? -ne 0 || ! -x "${command_path}" ]]; then
  if [[ -n "${command_path}" ]]; then
    _path_message=" in the expected location $(_relative "${command_path}")"
  fi
  fx-error "Cannot find executable for ${command_name}${_path_message}."\
    "If this is a tool produced by the build, make sure your"\
    "\`fx set\` config produces it in the $(_relative "$(get_host_tools_dir)") directory."
  exit 1
fi

declare -r cmd_and_args="$@"
shift # Removes the command name.

if [[ "${command_name}" != "vendor" || $# -lt 2 ]]; then
  metric_name="${command_name}"
else
  metric_name="vendor/$1/$2"
fi

track-command-execution "${metric_name}" "$@" &
declare -r start_time="$SECONDS"
"${command_path}" "$@"
declare -r retval=$?
declare -r end_time="$SECONDS"
declare -r ellapsed_time=$(( 1000 * (end_time - start_time) )) # milliseconds

if [ -z "${iterative}" ]; then
  track-command-finished "${ellapsed_time}" "${retval}" "${command_name}" "$@" &
  exit ${retval}
elif which inotifywait >/dev/null; then
  monitor_source_changes() {
    # Watch everything except out/ and files/directories beginning with "."
    # such as lock files, swap files, .git, etc'.
    inotifywait -qrme modify \
      --exclude "(/\.|lock|compile_commands.json)" \
      "${fuchsia_dir}" \
      @"${fuchsia_dir}"/out \
      @"${fuchsia_dir}"/zircon/public
  }
elif which apt-get >/dev/null; then
  echo "Missing inotifywait"
  echo "Try: sudo apt-get install inotify-tools"
  exit 1
elif which fswatch >/dev/null; then
  monitor_source_changes() {
    fswatch --one-per-batch --event=Updated \
      -e "${fuchsia_dir}"/out/ \
      -e "${fuchsia_dir}"/zircon/public/ \
      -e "/\." \
      -e "lock" \
      -e "/compile_commands.json" \
      .
  }
else
  echo "Missing fswatch"
  echo "Try: brew install fswatch"
  exit 1
fi

monitor_and_run() {
  local -r event_pipe="$1"
  local -r display_name="$2"
  shift 2

  # Explicitly bind $event_pipe to a numbered FD so read behaves consistently
  # on Linux and Mac shells ("read <$event_pipe" closes $event_pipe after the
  # first read on Mac bash).
  exec 3<"${event_pipe}"

  while read -u 3; do
    if [[ "$(uname -s)" != "Darwin" ]]; then
      # Drain all subsequent events in a batch.
      # Otherwise when multiple files are changes at once we'd run multiple
      # times.
      read -u 3 -d "" -t .01
    fi
    # Allow at most one fx -i invocation per Fuchsia dir at a time.
    # Otherwise multiple concurrent fx -i invocations can trigger each other
    # and cause a storm.
    echo "---------------------------------- fx -i ${display_name} ---------------------------------------"
    "$@"
    echo "--- Done!"
  done
}

monitor_and_run <(monitor_source_changes) "${cmd_and_args}" "${command_path}" "$@"