#!/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 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] ${cmd} ...
  --dir=BUILD_DIR           Path to the build directory to use when running COMMAND.
  -d=DEVICE[:SSH_PORT]      Target a specific device.
                            DEVICE may be a Fuchsia device name to be resolved using
                            device-finder or an IP address.
                            An IPv4 address must be specified directly, while an IPv6
                            need to be surrounded by brackets.
                            SSH_PORT, if specified, will be used for all commands
                            that rely on SSH to connect to the device instead of the
                            default SSH port (22).
                            Note: See "fx help set-device" for more help and to set
                            the default device for a BUILD_DIR.
  -i                        Iterative mode.  Repeat the command whenever a file is
                            modified under your Fuchsia directory, not including
                            out/.
  -x                        Print commands and their arguments as they are executed.
  -xx                       Print extra logging of the fx tool itself (implies -x)
END
  if [[ -n "$(list_optional_features)" ]]; then
    echo "  --enable|disable=FEATURE  Enable or disable a feature (non-persistent). Valid features:"
    help_optional_features
  fi
}

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/devshell/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 from a directory
that is contained in 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 "$@"
}

# 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.
#
# NOTE: The FUCHSIA_DIR environment variable is ignored here because it
# could point to a different Fuchsia checkout in some developer setups.
#
# This logic is replicated in //scripts/fx, //scripts/hermetic_env,
# //scripts/zsh_completion/_fx, and //src/developer/ffx/scripts. For
# consistency, copy any changes here to those files as well.
fuchsia_dir="$(pwd)"
while [[ ! -d "${fuchsia_dir}/.jiri_root" ]]; do
  fuchsia_dir="$(dirname "${fuchsia_dir}")"
  if [[ "${fuchsia_dir}" == "/" ]]; then
    echo "Cannot find the Platform Source Tree in a parent of directory: $(pwd)"
    exit 1
  fi
done

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 $?

declare -r cmd_locator_sh="${fuchsia_dir}/tools/devshell/lib/fx-cmd-locator.sh"
source "${cmd_locator_sh}" || exit $?

declare -r features_sh="${fuchsia_dir}/tools/devshell/lib/fx-optional-features.sh"
source "${features_sh}" || exit $?

while [[ $# -ne 0 ]]; do
  case $1 in
    --dir=*|-d=*|--disable=*|--enable=*)
      # Turn --switch=value into --switch value.
      arg="$1"
      shift
      set -- "${arg%%=*}" "${arg#*=}" "$@"
      continue
      ;;
    --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
      ;;
    --disable)
      if [[ $# -lt 2 ]]; then
        usage
        fx-error "Missing argument to --disable"
        exit 1
      fi
      shift # Removes --disable.
      feature="$1"
      if ! is_valid_feature "${feature}"; then
        fx-error "Unknown feature \"${feature}\". Valid values are: $(list_optional_features)"
        exit 1
      fi
      env_name="$(get_disable_feature_env_name "${feature}")"
      export ${env_name}=1
      ;;
    --enable)
      if [[ $# -lt 2 ]]; then
        usage
        fx-error "Missing argument to --enable"
        exit 1
      fi
      shift # Removes --enable.
      feature="$1"
      if ! is_valid_feature "${feature}"; then
        fx-error "Unknown feature \"${feature}\". Valid values are: $(list_optional_features)"
        exit 1
      fi
      env_name="$(get_disable_feature_env_name "${feature}")"
      export ${env_name}=0
      ;;
    -d)
      if [[ $# -lt 2 ]]; then
        usage
        fx-error "Missing device name for -d argument"
        exit 1
      fi
      shift # removes -d
      if ! is-valid-device "$1"; then
        fx-error "Invalid device: $1. See valid values in 'fx help set-device'"
        exit 1
      fi
      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[0]}" ]]; 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

# For each optional feature, force the existence of the FUCHSIA_DISABLE_* env
# variable. This is needed so that non-bash code can reliably use this
# to check for optional features that have default values.
for f in $(list_optional_features); do
  _disabled_env_name="$(get_disable_feature_env_name "${f}")"
  is_feature_enabled "$f"
  export ${_disabled_env_name}=$?
done

export FX_ENTRY_CMD="$command_name"

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

mkdir -p "${FX_CACHE_DIR}"

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

if [ -z "${iterative}" ]; then
  track-command-finished "${elapsed_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}" "$@"