suggest

#!/usr/bin/bash
#
# SPDX-FileCopyrightText: 2019 Dmytro Kolomoiets <amerlyq@gmail.com> and contributors
#
# SPDX-License-Identifier: Apache-2.0
#
#%SUMMARY: suggest completion for command prefix [relative to basedir]
#%USAGE: $ ./$0 /path/to/basedir/cmd/pfx [/path/to/basedir] [find_args..]
#%IDEA: reduce number of suggestions (show only API aliases but not content)
#%  * .   => .{bb,cf,jr}
#%  * .j  => .jr/
#%  * .jr => .jr/{a,b,c,d}
#%
#%PERF: 76ms total $ wiw kirie/suggest ~/.cache/wiw/.cf
set -o errexit -o noclobber -o noglob -o nounset -o pipefail

# THINK: prevent alias symlinks pointing to outside dirs -- or not ?
#   HACK:IDEA: wiw "(bin|sys)/" -> may directly point to /usr/bin :)

all=
find_args=()

case ${1-}
in -a|--all) all=1 && shift
esac

# MAYBE:BET: make "$1=basedir" obligatory and pass "-r|--relative" OR "-p|--absolute" to make args simpler
pfx=${1-}
base=${2-}
(($#>1)) && find_args=( "${@:3}" )

# ATT! don't use PWD as default directory
#  * BAD: it's too unexpected for "kirie" suite which must use its own defaults
#  * SECU:PERF: current dir can be HOME -- must prevent searching of all contained files indiscriminately
[[ ${pfx:0:1} == / ]] || pfx=${SUITE_CACHE_HOME:?}/$pfx

nm=${pfx##*/}
dir=${pfx%$nm}

# DECI:(LC_ALL=C): arbitrary sorting of punctuation VS proper sorting of any UTF8
findexe(){ local d args fmt='%p\n'
  d=$1 && shift

  if [[ -n $base ]]; then
    fmt=$(realpath --no-symlinks --relative-base="$base" -- "$d")
    [[ $fmt == /* ]] && exit 2
    [[ $fmt == . ]] && fmt='%P\n' || fmt+='/%P\n'
  fi

  # IDEA: return only aliases when "" or "*/", but search within aliases when "?*"
  ((all)) && args=( -L ) || args=( -H )
  args+=( "$d" -mindepth 1 \( -name '_*' -o -name '.git' \) -prune -o )
  ((all)) && args+=( -type f ) || args+=( \( -xtype f -o \( -xtype d -type l \) \) )
  args+=( -executable "$@" "${find_args[@]}" )

  [[ ${find_args[*]:+x} ]] || args+=( -printf "$fmt" )

  find "${args[@]}" | LC_ALL=C sort --ignore-case
}

if [[ $nm != . && $nm != .. ]]; then
  # [[ -z $pfx ]] && { findexe "$PWD"; exit; }
  [[ -d $pfx ]] && { findexe "$pfx"; exit; }
  # BUG:FIXME: must be relative if $base
  [[ -e $pfx ]] && { printf '%s\n' "$pfx"; exit; }
fi

# [[ -z $dir ]] && { findexe "$PWD" -path "${PWD}/${nm}?*"; exit; }
[[ -d $dir ]] && { findexe "$dir" -path "${pfx}?*"; exit; }
[[ -e $dir ]] && { printf '%s\n' "$dir"; exit; }

# ALT:(always exit 1): FAILED: inconsistency between ::
#   * "~/.cache/wiw/sss" -- no error for unknown file in existing dir
#   * "~/.cache/wiw/sss/xxx" -- ERROR for unknown file in unknown dir
exit 0