#!/usr/bin/env bash
# hl7-desanitize.sh — reverse hl7-sanitize: replace [[CATEGORY_NNNN]] tokens
# with original values from $LARRY_HOME/sanitize/lookup.tsv.
#
# Use this LOCALLY ONLY — at view time, in your terminal. Never feed
# desanitized output back into Larry; that defeats the whole point.
#
# Usage:
#   hl7-desanitize.sh [FILE]                  # read file or stdin
#   hl7-desanitize.sh --table PATH            # alternate table
#   hl7-desanitize.sh --token [[NAME_0001]]   # single token lookup
#
# Examples:
#   # View Larry's sanitized output unmasked, in less:
#   cat larry-output.txt | hl7-desanitize.sh | less
#
#   # Quick single-token lookup:
#   hl7-desanitize.sh --token "[[MRN_0001]]"
set -o pipefail

LARRY_HOME="${LARRY_HOME:-$HOME/.larry}"
DEFAULT_TABLE="$LARRY_HOME/sanitize/lookup.tsv"

# v0.8.26: shared control-byte sanitizer. Desanitized HL7 can carry C0 control
# bytes that corrupt a terminal when viewed un-redirected; strip them ONLY when
# stdout is a tty. Piping to `less` (a documented use) is NOT a tty, so the
# content passes through raw and less handles the control bytes itself. See
# lib/cygwin-safe.sh.
_HL7D_LIB_DIR="$(cd "$(dirname "$0")" && pwd)"
if [ -r "$_HL7D_LIB_DIR/cygwin-safe.sh" ]; then
  # shellcheck disable=SC1090,SC1091
  . "$_HL7D_LIB_DIR/cygwin-safe.sh"
else
  _sanitize_ctl_tty() { cat; }   # degrade safe: raw passthrough if lib missing
fi

die() { printf 'hl7-desanitize: %s\n' "$*" >&2; exit 1; }

table="$DEFAULT_TABLE"
single_token=""
input_file=""

while [ $# -gt 0 ]; do
  case "$1" in
    --table) shift; table="$1" ;;
    --token) shift; single_token="$1" ;;
    -h|--help) sed -n '2,20p' "$0"; exit 0 ;;
    -*) die "unknown flag: $1" ;;
    *) input_file="$1" ;;
  esac
  shift
done

[ -f "$table" ] || die "no lookup table at $table (sanitize first?)"

if [ -n "$single_token" ]; then
  awk -F'\t' -v t="$single_token" 'NR>1 && $1==t {print $3; found=1; exit} END{if (!found) {print "no such token: " t > "/dev/stderr"; exit 2}}' "$table" | _sanitize_ctl_tty
  exit "${PIPESTATUS[0]}"
fi

# Build sed expression set from lookup table
# Each line: token \t category \t original
# We want: s/\[\[CATEGORY_NNNN\]\]/original/g for each
# Note: original may contain sed metacharacters; escape them.

# Read table into awk, build replacement map, walk input substituting tokens.
awk_script='
BEGIN { RS = "\n" }
NR == FNR {
  # Reading table
  if ($1 == "token" || $1 == "") next
  # cols: 1=token, 2=category, 3=original
  tokens[$1] = $3
  next
}
{
  line = $0
  # Replace each known token in the line. Tokens look like [[X_NNNN]].
  # Find all matches and substitute.
  while (match(line, /\[\[[A-Z_]+_[0-9]+\]\]/)) {
    tok = substr(line, RSTART, RLENGTH)
    if (tok in tokens) {
      # Build new line by substring substitution
      line = substr(line, 1, RSTART-1) tokens[tok] substr(line, RSTART+RLENGTH)
    } else {
      # Unknown token — leave it, but skip past so we do not infinite-loop
      placeholder = "<<<unmapped:" tok ">>>"
      line = substr(line, 1, RSTART-1) placeholder substr(line, RSTART+RLENGTH)
    }
  }
  print line
}
'

if [ -n "$input_file" ]; then
  awk -F'\t' "$awk_script" "$table" "$input_file" | _sanitize_ctl_tty
  exit "${PIPESTATUS[0]}"
else
  awk -F'\t' "$awk_script" "$table" /dev/stdin | _sanitize_ctl_tty
  exit "${PIPESTATUS[0]}"
fi