#!/usr/bin/env bash
set -euo pipefail

if [ "${1:-}" = "--help" ] || [ "${1:-}" = "-h" ]; then
  cat <<'USAGE'
Purpose: Given a unified-diff hunk that touches a token source file
         (src/design-tokens/* or tailwind.config.*), emit the tokens the
         diff adds. Deterministic so the LLM doesn't re-derive what counts
         as a "new token" from the prose of the diff.

Usage:   bash scripts/detect-token-additions.sh                       (reads stdin)
         bash scripts/detect-token-additions.sh <file>                (reads file)

Recognised additions:
  Lines beginning with `+` (and not `+++`) that contain a property
  declaration like `<key>: '<value>'` or `<key>: "<value>"` where `<value>`
  looks like a token value (hex, px, rem, em).

Output:  TSV rows to stdout:
           <key>\t<value>
         Diagnostics to stderr.

USAGE
  exit 0
fi

if [ "${1:-}" = "" ] || [ "${1:-}" = "-" ]; then
  body=$(cat)
elif [ -f "$1" ]; then
  body=$(cat "$1")
else
  printf 'error: file not found: %s\n' "$1" >&2
  exit 2
fi

printf '%s\n' "$body" | awk '
  /^\+\+\+/ { next }   # ignore file headers
  /^\+/ {
    line = $0
    sub(/^\+/, "", line)
    # Accept either an identifier key (`brand:`) or a quoted key
    # (`"14": '56px'` or `'14': '56px'`): Tailwind config commonly uses both.
    if (match(line, /([A-Za-z][A-Za-z0-9_-]*|['"'"'"][A-Za-z0-9_-]+['"'"'"])[[:space:]]*:[[:space:]]*['"'"'"][^'"'"'"]+['"'"'"]/)) {
      s = substr(line, RSTART, RLENGTH)
      colon = index(s, ":")
      key = substr(s, 1, colon - 1)
      rest = substr(s, colon + 1)
      gsub(/[[:space:]]/, "", key)
      gsub(/^[[:space:]]+/, "", rest)
      # Strip surrounding quotes from key and value.
      gsub(/^['"'"'"]/, "", key)
      gsub(/['"'"'"]$/, "", key)
      gsub(/^['"'"'"]/, "", rest)
      gsub(/['"'"'"]$/, "", rest)
      # Only accept token-shaped values.
      if (rest ~ /^#[0-9A-Fa-f]+$/ || rest ~ /^[0-9]+(\.[0-9]+)?(px|rem|em)$/) {
        printf "%s\t%s\n", key, rest
      }
    }
  }
'