#!/bin/bash -e

set -o errexit -o pipefail # errexit in case caller's #! line missing -e

if test ! "$_util_sh_include_guard_utils"; then

_util_sh_include_guard_utils=1

isset() { test "${!1+isset}"; }

realpath() { readlink -f -- "$1"; }

str2varname() { echo "${1//[^a-zA-Z0-9_]/_}"; }

include_guard_var() { str2varname "$(realpath "$1")"; }

self_not_included() # usage: if self_not_included; then ... fi

{

	test $# -ge 1 || set -- "${BASH_SOURCE[1]}"

	local include_guard="$(include_guard_var "$1")"

	alias self_being_included=false

	! isset "$include_guard" && \

	{ eval "$include_guard"=1; alias self_being_included=true; }

}

# to load newly-defined aliases for use in functions in the same file:

## fi # load new aliases

## if self_being_included; then

# this is needed because aliases defined inside an if statement are not

# available inside that if statement

fi

if self_not_included "${BASH_SOURCE[0]}"; then

#### options

shopt -s expand_aliases

#### stubs

__caller_indent='log_indent="$log_indent$log_indent_step"'

alias caller_indent="$__caller_indent"

alias indent="declare $__caller_indent"

function echo_func() { :; }

alias echo_func='"echo_func" "$FUNCNAME" "$@" && indent || true'

function echo_run() { :; }

alias echo_run='"echo_run" ' # last space alias-expands next word

function echo_vars() { :; }

#### vars

set_var() { eval "$1"'="$2"'; }

set_default() { if ! isset "$1"; then set_var "$@"; fi; }

set_inv() { set_var no_"$1" "$(test "${!1}" || echo 1)"; }

# usage: local var=...; local_inv

alias local_inv='declare "no_$var=$(test "${!var}" || echo 1)"'

unexport() { export -n "$@"; }

	# `declare +x` won't work because it defines the var if it isn't set

alias local_export='declare -x' # combines effects of local and export

get_prefix_vars() { : "${prefix:?}"; eval echo '${!'$prefix'*}'; }

# usage: local prefix=..._; import_vars

# when used inside another alias 2+ levels deep, *must* be run inside a function

alias import_vars="$(cat <<'EOF'

: "${prefix:?}"

declare src_var dest_var

for src_var in $(get_prefix_vars); do

	dest_var="${src_var#$prefix}"

	declare "$dest_var=${!src_var}"; echo_vars "$dest_var"

done

EOF

)"

#### caching

## shell-variable-based caching

# usage: local cache_key=...; load_cache; \

# if ! cached; then save_cache value || return; fi; echo_cached_value

# cache_key for function inputs: "$(declare -p kw_param...) $*"

alias load_cache='declare cache_var="$(str2varname "${FUNCNAME}___$cache_key")"'

alias cached='isset "$cache_var"'

alias save_cache='set_var "$cache_var"'

alias echo_cached_value='echo "${!cache_var}"'

clear_cache() # usage: func=... clear_cache

{ : "${func:?}"; unset $(prefix="${func}___" get_prefix_vars); }

fi # load new aliases

if self_being_included; then

#### aliases

unalias() { builtin unalias "$@" 2>&- || true; } # no error if undefined

# usage: alias alias_='var=value run_cmd '

function run_cmd() { "$@"; }

alias run_cmd='"run_cmd" ' # last space alias-expands next word

alias_append() { eval $(alias "$1")'"$2"'; } # usage: alias_append alias '; cmd'

#### functions

kw_params() # usage: func() { kw_params param_var...; }; ...; param_var=... cmd

# removes keyword-param-only vars from the environment

{ unexport "$@"; }

alias self='command "$FUNCNAME"' # usage: wrapper() { self ...; }

alias self_sys='command -p "$FUNCNAME"' # usage: wrapper() { self_sys ...; }

pf() { declare -f "$@"; } # usage: pf function # prints func decl for debugging

all_funcs() # usage: for func in $(all_funcs); do ...; done # all declared funcs

{ declare -F|while read -r line; do echo -n "${line#declare -f } "; done; }

#### exceptions

# usage: cmd || { save_e; ...; rethrow; }

alias export_e='e=$?'

alias save_e='declare e=$?'

alias rethrow='return "$e"'

alias rethrow_subshell='exit "$e"'

fi # load new aliases

if self_being_included; then

# usage: try cmd...; ignore_e status; if catch status; then ...; fi; end_try

function try() { e=0; benign_error=1 "$@" || { export_e; true; }; }

alias try='declare e; "try" ' # last space alias-expands next word

catch() { test "$e" -eq "$1" && e=0; }

ignore_e() { catch "$@" || true; }

alias end_try='rethrow'

alias end_try_subshell='rethrow_subshell'

ignore() { save_e; ignore_e "$@"; rethrow; } # usage: try cmd || ignore status

### signals

sig_e() { echo $(( 128+$(kill -l "$1") )); } # usage: sig_e SIGINT, etc.

ignore_sig() { ignore "$(sig_e "$1")"; }

# usage: piped_cmd cmd1...|cmd2... # cmd2 doesn't read all its input

function piped_cmd() { "$@" || ignore_sig SIGPIPE; }

alias piped_cmd='"piped_cmd" ' # last space alias-expands next word

fi # load new aliases

if self_being_included; then

#### integers

let!() { let "$@" || true; } # always returns true; safe to use for setting

	# "If the last ARG evaluates to 0, let returns 1" (`help let`)

bool2int() { try test ! "$1"; echo "$e"; } # empty->0; non-empty->1

int2exit() { (( "$1" != 0 )); }

exit2bool() { if (( $? == 0 )); then echo 1; fi } # 0->non-empty; !=0->empty

#### floats

int_part() { echo "${1%%.*}"; }

dec_suffix() { echo "${1#$(int_part "$1")}"; }

round_down() { int_part "$1"; }

float+int() { echo "$(($(int_part "$1")+$2))$(dec_suffix "$1")"; }

float_set_min() { if (($(int_part $1) >= $2)); then echo $1; else echo $2; fi; }

#### strings

starts_with() { test "${2#$1}" != "$2"; } # usage: starts_with pattern str

match_prefix() # usage: match_prefix pattern str

{ if starts_with "$1" "$2"; then echo "${2%${2#$1}}"; fi }

repeat() # usage: str=... n=... repeat

{

	: "${str?}" "${n:?}"; local result= n="$n" # n will be modified in function

	for (( ; n > 0; n-- )); do result="$result$str"; done

	echo "$result"

}

sed_cmd="sed -`case "$(uname)" in Darwin) echo E;; *) echo r;; esac`"

alias sed="$sed_cmd"

fi # load new aliases

if self_being_included; then

rtrim() { log+ 3; sed 's/[[:space:]]+$//' <<<"$1"; }

#### arrays

join() { local IFS="$delim"; echo "$*"; } # usage: delim=... join elems...

reverse() # usage: array=($(reverse args...))

{

	local i

	for (( i=$#; i > 0; i-- )); do printf '%q ' "${!i}"; done

}

contains() # usage: contains value in_array...

{

	local value="$1"; shift

	local elem

	for elem in "$@"; do if test "$elem" = "$value"; then return 0; fi; done

	return 1

}

#### streams

pipe_delay() # usage: cmd1 | { pipe_delay; cmd2; }

{ sleep 0.1; } # s; display after leading output of cmd1

#### verbose output

err_fd=2 # stderr

usage() { echo "Usage: $1" >&2; return 2; }

### log++

log_fd=2 # initially stderr

if test "$explicit_errors_only"; then verbosity=0; fi # hide startup logging

# set verbosity

if isset verbose; then : "${verbosity:=$(bool2int "$verbose")}"; fi

if isset vb; then : "${verbosity:=$vb}"; fi

: "${verbosity=1}" # default

: "${verbosity:=0}" # ensure non-empty

export verbosity # propagate to invoked commands

export PS4 # follows verbosity, so also propagate this

is_outermost="$(! isset log_level; exit2bool)" # if util.sh env not yet set up

# set log_level

: "${log_level=$(( ${#PS4}-1 ))}" # defaults to # non-space symbols in PS4

export log_level # propagate to invoked commands

verbosity_int() { round_down "$verbosity"; }

# verbosities (and `make` equivalents):

# 0: just print errors. useful for cron jobs.

#    vs. make: equivalent to --silent, but suppresses external command output

# 1: also external commands run. useful for running at the command line.

#    vs. make: not provided (but sorely needed to avoid excessive output)

# 2: full graphical call tree. useful for determining where error occurred.

#    vs. make: equivalent to default verbosity, but with much-needed indents

# 3: also values of kw params and variables. useful for low-level debugging.

#    vs. make: not provided; need to manually use $(error $(var))

# 4: also variables in util.sh commands. useful for debugging util.sh.

#    vs. make: somewhat similar to --print-data-base

# 5: also variables in logging commands themselves. useful for debugging echo_*.

#    vs. make: not provided; need to search Makefile for @ at beginning of cmd

# 6+: not currently used (i.e. same as 5)

# definition: the log_level is the minimum verbosity needed to display a message

# for messages that use can_log(), the log_level starts with *1*, not 0

# for unfiltered messages, the log_level is 0 (i.e. still output at verbosity=0)

# to view a message's log_level, count the # of + signs before it in the output

fi # load new aliases

if self_being_included; then

# usage: in func:      log++; ...         OR  log_local; "log++"; ...

#        outside func: log++; ...; log--

#        before cmd:  "log++" cmd  OR  "log+" # cmd  OR  "log++" "log++" cmd

# with a cmd, assignments are applied just to it, so log_local is not needed

# without a cmd, "$@" expands to nothing and assignments are applied to caller

# "${@:2}" expands to all of $@ after *1st* arg, not 2nd ($@ indexes start at 1)

log+()

{

	# no local vars because w/o cmd, assignments should be applied to caller

	PS4="$(str="${PS4:0:1}" n=$((log_level+$1-1)) repeat)${PS4: -2}"; \

	log_level=$((log_level+$1)) \

	verbosity="$(float+int "$verbosity" "-$1")" "${@:2}"

}

log++() { log+  1 "$@"; }

log--() { log+ -1 "$@"; }

alias log_local=\

'declare PS4="$PS4" log_level="$log_level" verbosity="$verbosity"'

alias log+='log_local; "log+"' # don't expand next word because it's not a cmd

alias log++='log_local; "log++" ' # last space alias-expands next word

alias log--='log_local; "log--" ' # last space alias-expands next word

# no clog+ alias because next word is not a cmd

alias clog++='"log++" ' # last space alias-expands next word

alias clog--='"log--" ' # last space alias-expands next word

verbosity_min() # usage: verbosity_min min

{ if test "$(verbosity_int)" -lt "$1"; then verbosity="$1"; fi; }

alias verbosity_min='log_local; "verbosity_min"'

# indent for call tree. this is *not* the log_level (below).

: "${log_indent_step=| }" "${log_indent=}"

export log_indent_step log_indent # propagate to invoked commands

# see indent alias in stubs

fi # load new aliases

if self_being_included; then

can_log() { test "$(verbosity_int)" -gt 0; }

	# verbosity=0 turns off all logging

log() { if can_log; then echo "$log_indent$PS4$1" >&"$log_fd"; fi; }

log_custom() # usage: symbol=... log_custom msg

{ log_indent="${log_indent//[^ ]/$symbol}" PS4="${PS4//[^ ]/$symbol}" log "$@";}

log_err() { symbol='#' verbosity=1 log_fd="$err_fd" log_custom "$@"; }

log_info() { symbol=: log_custom "$@"; }

die() # usage: cmd || [type=...] die msg # msg can use $? but not $()

{ save_e; kw_params type; "log_${type:-err}" "$1"; rethrow; }

die_e() # usage: cmd || [benign_error=1] die_e [|| handle error]

{

	save_e; kw_params benign_error

	if test "$benign_error"; then log++; fi

	type="${benign_error:+info}" die "command exited with \

$(if test "$benign_error"; then echo status; else echo error; fi) $e"

	rethrow

}

#### functions

func_exists() { declare -f "$1" >/dev/null; }

copy_func() # usage: from=... to=... copy_func

# $to must not exist. to get around the no-clobber restriction, use `unset -f`.

{

	: "${from:?}" "${to:?}"

	func_exists "$from" || die "function does not exist: $from"

	! func_exists "$to" || die "function already exists: $to"

	local from_def="$(declare -f "$from")"

	eval "$to${from_def#$from}"

}

func_override() # usage: func_override old_name__suffix

{ from="${1%__*}" to="$1" copy_func; }

ensure_nested_func() # usage: func__nested_func() { ensure_nested_func; ... }

{

	local nested_func="${FUNCNAME[1]}"

	local func="${nested_func%%__*}"

	contains "$func" "${FUNCNAME[@]}" || \

		die "$nested_func() must be used by $func()"

}

#### paths

# cache realpath

: "${realpath_cache=}" # default off because slower than without

if test "$realpath_cache"; then

func_override realpath__no_cache

realpath() # caches the last result for efficiency

{

	local cache_key="$*"; load_cache

	if ! cached; then save_cache "$(realpath__no_cache "$@")" || return; fi

	echo_cached_value

}

fi

rel_path() # usage: base_dir=... path=... rel_path

{

	kw_params base_dir path

	: "${base_dir:?}" "${path:?}"

	local path="$path/" # add *extra* / to match path when exactly = base_dir

	path="${path#$base_dir/}" # remove prefix shared with base_dir

	path="${path%/}" # remove any remaining extra trailing /

	if test ! "$path"; then path=.; fi # ensure non-empty

	echo_vars path

	echo "$path"

}

cd -P . # expand symlinks in $PWD so it matches the output of realpath

# do before setting $top_script_abs so realpath has less symlinks to resolve

canon_rel_path() # usage: [base_dir=...] canon_rel_path path

{

	kw_params base_dir; local base_dir="${base_dir-$PWD}"

	base_dir="$(realpath "$base_dir")" || return

	local path; path="$(realpath "$1")" || return

	rel_path

}

# makes $1 a canon_rel_path if it's a filesystem path

alias cmd2rel_path="$(cat <<'EOF'

if test "$(type -t "$1")" = file && test -e "$1"; then # not relative to PATH

	declare _1="$1"; shift

	_1="$(clog++ canon_rel_path "$_1")" || return

	set -- "$_1" "$@"

fi

EOF

)"

#### verbose output

### command echoing

alias echo_params='log "$*"'

fi # load new aliases

if self_being_included; then

echo_cmd() { echo_params; }

function echo_run() { echo_params; "$@"; }

# see echo_run alias after stub

echo_eval() { echo_params; builtin eval "$@"; }

# usage: redirs=(...); [cmd_name_log_inc=#] echo_redirs_cmd

function echo_redirs_cmd()

{

	local cmd_name_log_inc="${cmd_name_log_inc-0}"

	# print <>file redirs before cmd, because they introduce it

	"log+" "$cmd_name_log_inc" echo_cmd "$@" $(

		set -- "${redirs[@]}" # operate on @redirs

		while test "$#" -gt 0 && starts_with '[<>][^&]' "$1"

		do log "$1 \\"; shift; done # log() will run *before* echo_cmd itself

		echo "$@"

	)

}

alias echo_redirs_cmd='"echo_redirs_cmd" "$@"'

## vars

echo_vars() # usage: echo_vars var...

{

	log+ 2

	if can_log; then

		local var

		for var in "${@%%=*}"; do

			if isset "$var"; then log "$(declare -p "$var")"; fi

		done

	fi

}

echo_export() { builtin export "$@"; echo_vars "$@"; }

alias export="echo_export" # automatically echo env vars when they are set

func_override kw_params__lang

kw_params() { kw_params__lang "$@"; echo_vars "$@"; } # echo all keyword params

## functions

# usage: local func=...; set_func_loc; use $file, $line

alias set_func_loc="$(cat <<'EOF'

: "${func:?}"

local func_info="$(shopt -s extdebug; declare -F "$func")" # 'func line file'

func_info="${func_info#$func }"

local line="${func_info%% *}"

local file="${func_info#$line }"

EOF

)"

fi # load new aliases

if self_being_included; then

func_loc() # gets where function declared in the format file:line

{

	local func="$1"; set_func_loc

	file="$(canon_rel_path "$file")" || return

	echo "$file:$line"

}

# usage: func() { [minor=1] echo_func; ... }

function echo_func()

# usage: [minor=1] "echo_func" "$FUNCNAME" "$@" && indent || true

# exit status: whether function call was echoed

{

	kw_params minor

	local func="$1"; shift

	log++; if test "$minor"; then log++; fi

	local loc; loc="$(clog++ func_loc "$func")" || return

	echo_cmd "$loc" "$func" "$@"

	can_log

}

# see echo_func alias after stub

fi # load new aliases

if self_being_included; then

#### streams

fd_exists() { (: <&"$1") 2>/dev/null; }

require_fd_not_exists() # usage: require_fd_not_exists fd || return 0

{ ! fd_exists "$1" || type=info die "fd $1 already exists, skipping"; }

set_fds() # usage: set_fds redirect...

{

	echo_func

	# add #<>&- before every #<>&# reopen to fix strange bash bug

	local redirs=()

	for i in "$@"; do

		local redir_prefix="$(match_prefix '*[<>]' "$i")"

		if test "$redir_prefix"; then redirs+=("$redir_prefix&-"); fi

		redirs+=("$i")

	done

	set -- "${redirs[@]}"

	if (($# > 0)); then echo_eval exec "$@"; fi

}

fd_set_default() # usage: fd_set_default 'dest[<>]src'

{

	echo_func

	local dest="${1%%[<>]*}"

	require_fd_not_exists "$dest" || return 0

	set_fds "$1"

}

function filter_fd() # usage: (fd=# filter_fd filter_cmd...; with filter...)

# useful e.g. to filter logging output or highlight errors

{

	echo_func; kw_params fd; : "${fd?}"

	set_fds "$fd>" >(pipe_delay; redirs=(">&$fd" "${redirs[@]}"); redir "$@")

	pipe_delay; pipe_delay # wait for >()'s pipe_delay and initial logging

}

alias filter_fd='"filter_fd" ' # last space alias-expands next word

# convention: use fd 40/41/42 for command-specific alternate stdin/stdout/stderr

# do NOT use 1x, which are used by eval (which is used by set_fds())

# do NOT use 2x, which are used as global stdin/stdout/stderr

# do NOT use 3x, which are used for logging

setup_log_fd() # view logging output at verbosity >= 5

{

	log+ 4; log-- echo_func 

	fd_set_default '30>&2' || true # stdlog

	log_fd=30 # stdlog

}

setup_log_fd

set_global_fds()

# allows commands to access global stdin/stdout/stderr using fd 20/21/22

# this works even when /dev/tty isn't available

# view logging output at verbosity >= 3

{

	log+ 2; log-- echo_func

	# ignore errors if a source fd isn't open

	fd_set_default '20<&0' || true

	fd_set_default '21>&1' || true

	fd_set_default '22>&2' || true

}

set_global_fds

# usage: explicit_errors_only=1 script...

# show only explicitly-displayed errors (which have been redirected to fd 22)

# most of the time this has the same effect as `verbosity=0 script...`,

# which displays everything that isn't explicitly hidden

# this option should only be used for testing the explicit error displaying

if test "$explicit_errors_only"; then disable_logging; fi

echo_vars is_outermost

#### paths

top_symlink_dir="$(dirname "$0")"; echo_vars top_symlink_dir

top_symlink_dir_abs="$(realpath "$top_symlink_dir")"

	echo_vars top_symlink_dir_abs

top_script_abs="$(realpath "$0")"; echo_vars top_script_abs # outermost script

	# realpath this before doing any cd so this points to the right place

top_dir_abs="$(dirname "$top_script_abs")"; echo_vars top_dir_abs

set_paths()

{

	top_script="$(clog++ canon_rel_path "$top_script_abs")" || return

		echo_vars top_script

	top_dir="$(dirname "$top_script")" || return; echo_vars top_dir

}

set_paths

PATH_rm() # usage: PATH_rm path... # removes components from the PATH

{

	echo_func; echo_vars PATH; : "${PATH?}"

	PATH=":$PATH:" # add *extra* : to match at beginning and end

	for path in "$@"; do PATH="${PATH//:$path:/:}"; done

	PATH="${PATH#:}" # remove any remaining extra leading :

	PATH="${PATH%:}" # remove any remaining extra trailing :

	echo_vars PATH

}

no_PATH_recursion() # usage: (no_PATH_recursion; cmd...)

# allows running a system command of the same name as the script

{

	echo_func

	PATH_rm "$top_dir_abs" "$top_symlink_dir" "$top_symlink_dir_abs" "$top_dir"

}

#### verbose output

## internal commands

.()

{

	cmd2rel_path; set -- "$FUNCNAME" "$@"

	if (log++; echo_params; can_log); then indent; fi

	builtin "$@"

}

cd() # indent is permanent within subshell cd was used in

{

	log++ echo_func

	cmd2rel_path; echo_cmd "$FUNCNAME" "$@"

	if can_log; then caller_indent; fi

	# -P: expand symlinks so $PWD matches the output of realpath

	builtin "$FUNCNAME" -P "$@"

	func=realpath clear_cache

	set_paths

}

## external commands

disable_logging() { set_fds "$log_fd>/dev/null"; }

function redir() # usage: local redirs=(#<>...); redir cmd...; unset redirs

# to view only explicitly-displayed errors: explicit_errors_only=1 script...

{

	echo_func; kw_params redirs

	case "$1" in redir|command) "$@"; return;; esac # redir will be run later

	(

		log++ set_fds "${redirs[@]}"

		(case "$1" in command__exec) shift;; esac; echo_redirs_cmd)

		"$@"

	) || return

}

alias redir='"redir" ' # last space alias-expands next word

alias_append save_e '; unset redirs' # don't redirect error handlers

command() # usage: [cmd_log_fd=|1|2|#] [verbosity_min=] command extern_cmd...

{

	echo_func; kw_params log_fd cmd_log_fd redirs verbosity_min

	# if no cmd_log_fd, limit log_fd in case command uses util.sh

	local cmd_log_fd="${cmd_log_fd-$log_fd}"

	local redirs=("${redirs[@]}")

	# determine redirections

	if test "$cmd_log_fd"; then

		if can_log; then

			if test "$cmd_log_fd" != "$log_fd"; then

				redirs+=("$cmd_log_fd>&$log_fd")

			fi # else no redir needed

		else redirs+=("$cmd_log_fd>/dev/null");

		fi

	fi

	cmd2rel_path

	redir command__exec "$@" || die_e

}

command__exec()

{

	ensure_nested_func

	if can_log; then indent; fi

	if test "$verbosity_min"; then verbosity_min "$verbosity_min"; fi

	builtin command "$@"

}

# auto-echo common external commands

for cmd in env rm; do alias "$cmd=command $cmd"; done; unset cmd

### external command input/output

echo_stdin() # usage: input|echo_stdin|cmd

{

	if can_log; then

		pipe_delay

		echo ----- >&"$log_fd"

		tee -a /dev/fd/"$log_fd";

		echo ----- >&"$log_fd"

	else cat

	fi

}

echo_stdout() { echo_stdin; } # usage: cmd|echo_stdout

#### commands

already_exists_msg() # usage: cond || what=... already_exists_msg || return 0

{ type=info die "$what already exists, skipping"; }

require_not_exists() # usage: require_not_exists file || return 0

{ test ! -e "$1" || what="file \"$1\"" already_exists_msg; }

function to_file() # usage: stdout=... [if_not_exists=1] [del=] to_file cmd...

# auto-removes a command's output file on error (like make's .DELETE_ON_ERROR)

{

	echo_func; kw_params stdout if_not_exists del

	: "${stdout?}"; local del="${del-1}"

	if test "$if_not_exists"; then require_not_exists "$stdout" || return 0; fi

	local redirs=("${redirs[@]}" ">$stdout")

	redir "$@" || { save_e; test ! "$del" || rm "$stdout"; rethrow; }

}

alias to_file='"to_file" ' # last space alias-expands next word

log_bg() { symbol='&' log_custom "$@"; }

log_last_bg() { log_bg '$!='"$!"; }

function bg_cmd() { echo_func; "$@" & log_last_bg; } # usage: bg_cmd cmd...

alias bg_cmd='"bg_cmd" ' # last space alias-expands next word

run_args_cmd() # runs the command line args command

{

	eval set -- "$(reverse "${BASH_ARGV[@]}")"

	test $# -ge 1 || set -- all

	echo_cmd "$top_script" "$@"; "$@"

}

fwd() # usage: subdirs=(...); fwd "$FUNCNAME" "$@"

{

	echo_func

	: "${subdirs?}"

	for subdir in "${subdirs[@]}"; do "$top_dir"/"$subdir"/run "$@"; done

}

#### filesystem

alias file_size=\

"stat `case "$(uname)" in Darwin) echo -f %z;; *) echo --format=%s;; esac`"

#### URLs

localize_url() { test _"$1" = _"$(hostname -f)" || echo "$1"; }

fi