#!/bin/bash

set -e

blob_bin_dir="$(cd "$(dirname "$(readlink -f "${BASH_SOURCE[0]}")")" && pwd)"

command_file() {
  local name="$1"
  if [[ -x "$blob_bin_dir/$name" ]]; then
    printf '%s\n' "$blob_bin_dir/$name"
  else
    command -v "$name" 2>/dev/null
  fi
}

resolve_command() {
  local words=("$@")
  local word_count=${#words[@]}
  local words_used name joined
  for (( words_used = word_count; words_used > 0; words_used-- )); do
    joined=$(printf '%s-' "${words[@]:0:words_used}")
    name="blob-${joined%-}"
    if [[ -n $(command_file "$name") ]]; then
      printf '%s %s\n' "$words_used" "$name"
      return 0
    fi
  done
  return 1
}

metadata_value() {
  sed -n "s/^# blob:$2=//p" "$1" | head -1
}

is_hidden() {
  grep -q '^# blob:hidden=true' "$1" 2>/dev/null
}

list_commands() {
  local file base summary
  for file in "$blob_bin_dir"/blob-*; do
    [[ -f $file ]] || continue
    is_hidden "$file" && continue
    base=$(basename "$file")
    summary=$(metadata_value "$file" summary)
    printf '  %-28s %s\n' "${base#blob-}" "$summary"
  done
}

show_command_help() {
  local name="$1"
  local file
  file=$(command_file "$name")
  printf '%s\n' "$(metadata_value "$file" summary)"
  local args
  args=$(metadata_value "$file" args)
  printf '\nUsage: %s %s\n' "${name//-/ }" "$args"
  local examples
  examples=$(metadata_value "$file" examples)
  [[ -n $examples ]] && printf '\nExample: %s\n' "$examples"
  return 0
}

show_usage() {
  cat <<USAGE
Usage: blob <command> [args...]

Commands are files named blob-<area>-<verb>. Both forms work:

  blob theme set tokyo-night
  blob-theme-set tokyo-night

Available commands:
USAGE
  list_commands
  printf '\nRun "blob help <command>" for details on one.\n'
}

case "${1-}" in
"" | help | --help | -h)
  shift || true
  if (( $# == 0 )); then
    show_usage
    exit 0
  fi
  if resolution=$(resolve_command "$@"); then
    show_command_help "${resolution#* }"
    exit 0
  fi
  echo "Unknown command: $*" >&2
  exit 1
  ;;
esac

if ! resolution=$(resolve_command "$@"); then
  echo "Unknown command: $*" >&2
  echo 'Run "blob" to list commands.' >&2
  exit 1
fi

words_used="${resolution%% *}"
command_name="${resolution#* }"
shift "$words_used"

exec "$(command_file "$command_name")" "$@"