#!/bin/bash
# Copyright 2018 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.

#### CATEGORY=Device discovery
### set the default device to interact with

## usage: fx set-device [DEVICE[:SSH_PORT]]
##
## fx set-device is used to specify the default device to target for
## the current Fuchsia build directory, i.e. $FUCHSIA_BUILD_DIR.
## This means a device is set within the scope of a build directory (i.e. out/arm64 may
## have a different default device than out/x64).
##
## If no device name is given, set-device will attempt to discover devices. If
## one device is found, that device is set as the default for the current build
## directory. If more than one device is found, the user must select one.
##
## If specified, DEVICE may be a Fuchsia device name or network address that will be resolved
## using ffx.
##
## The default device resolution is performed by ffx using
## a prioritized list of configuration to resolve the default target.
## Once there is a value, the remainder of the list is ignored.
##
## * Specify the target on the ffx command line with --target.
## * If configured, use the user level configuration set by ffx target default set.
##   This user level configuration is stored relative to $HOME. This is controlled by
##   running `ffx target default set`.
## * The default configuration compiled into ffx checks two environment variables:
##     "$FUCHSIA_DEVICE_ADDR"
##     "$FUCHSIA_NODENAME"
##    These are used by Fuchsia infra jobs to specify which target should be used
##     when running a specific test FUCHSIA_NODENAME is also set to any
##     build-directory default target set by `fx set-device`.
## * If only one device is discovered
##
## If there is still no target device identified, or if there are multiple devices discovered,
## an error is returned indicating a specific device needs to be identified as the default device
## for that command.
##
## Examples:
##   fx set-device strut-wind-ahead-turf
##   fx set-device strut-wind-ahead-turf:222
##   fx set-device 192.168.1.2
##   fx set-device 192.168.3.1:8022
##   fx set-device [fe80::7:8%eth0]
##   fx set-device [fe80::7:8%eth0]:5222
##   fx set-device
##
## To unset, use `fx unset-device`.

# -e exit immediately on commmand failure
# -o pipefail the return value is the value of rightmost command in a pipeline.
set -e -o pipefail

source "$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"/lib/vars.sh || exit $?
fx-standard-switches "$@"
fx-config-read
fx-fail-if-device-specified

function select_device() {
  IFS=$'\n' read -rd '' -a devices <<<"$1"
  select choice in "${devices[@]}"; do
    echo "${devices[$((REPLY-1))]}"
    break
  done
}

# FX_REMOTE_INVOCATION is set by serve-remote to supress the warning
# for that use case.
if is-remote-workflow-device && [[ -z "${FX_REMOTE_INVOCATION}" ]]; then
  fx-warn "Local configuration indicates a remote-workflow setup"
  fx-warn "  'fx set-device' does not work correctly at this end of a remote setup"
  fx-warn "Execute set-device on the local machine in order to change targets in the remote flow"
fi

device="$1"
if [[ -z "$device" ]]; then
  devices="$(fx-target-finder-info | cut -d ' ' -f 2)"
  if [[ -z "${devices}" ]]; then
    fx-error "No devices discovered, please supply a device name"
    exit 1
  fi
  if [[ "$(echo "$devices" | wc -l)" -ge 2 ]]; then
    fx-error "Multiple devices found, please pick one from the list:"
    device=$(select_device "$devices")
  else
    device="${devices}"
  fi
elif ! is-valid-device "${device}"; then
  fx-error "Invalid device: ${device}"
  fx-command-help
  exit 1
fi

if [[ ! -d "${FUCHSIA_BUILD_DIR}" ]]; then
  fx-error "Build directory ${FUCHSIA_BUILD_DIR} does not exist, run \"fx set\" first."
  exit 1
fi

echo "Default device for '${FUCHSIA_BUILD_DIR}' is now ${device}"
echo "$device" > "${FUCHSIA_BUILD_DIR}.device"

# Ensure the below checks will report the correct error message.
export FUCHSIA_NODENAME="${device}"

# Check if the user has set a default target via environment variable(s) which
# can override the effectiveness of this command.
function overridden-env-var-error {
  # This line is executed after echoing `Default device for ... is now $device`.
  fx-error "However, you've overriden this value by setting ${ENV_VARS}."
  fx-error "If you want to use \"$device\", please unset the ${ENV_VAR_NAMES} environment variable."

  exit 1
}
fx-if-target-set-by-env overridden-env-var-error