#!/usr/bin/env bash
# check-cards-against-spec — verify scenario cards carry their spec table's
# falsification lines verbatim. See authoring-cards-from-a-spec.md.
set -euo pipefail

usage() {
  cat <<'EOF'
Usage: check-cards-against-spec <spec.md> <cards-dir>

Verifies the spec's "E2E scenario cards" table against the cards directory:
  1. table parses (>=1 row; non-empty Card and Falsification cells)
  2. every row has <cards-dir>/<card>.md
  3. every card contains its Falsification line verbatim
     (whitespace-normalized, fixed-string, case-sensitive)
  4. every card has **What this covers** (bold inline) and ## headings
     Pre-state, Steps, Expected, Cleanup (Sharp edges not required)
  5. extra cards in <cards-dir> are reported as warnings, not failures

Exit: 0 all pass; 1 check failed; 2 no "E2E scenario cards" table; 64 usage.
EOF
}

[ "${1:-}" = "--help" ] && { usage; exit 0; }
[ $# -eq 2 ] || { usage >&2; exit 64; }
SPEC="$1"; CARDS="$2"
[ -f "$SPEC" ] || { echo "error: spec not found: $SPEC" >&2; exit 64; }
[ -d "$CARDS" ] || { echo "error: cards dir not found: $CARDS" >&2; exit 64; }

FAILURES=0
fail() { echo "FAIL: $1"; FAILURES=$((FAILURES + 1)); }
warn() { echo "warn: $1"; }

# Collapse every whitespace run to one space; trim ends. (Normative per the
# design spec: markdown re-wrapping must not defeat the verbatim check.)
normalize() { tr -s '[:space:]' ' ' | sed -e 's/^ //' -e 's/ $//'; }

# Text of the card's Expected section only (case-insensitive heading match,
# any ##+ level; section ends at the next heading or EOF).
expected_section() {
  awk '
    /^#{1,6}[[:space:]]/ {
      low = tolower($0)
      if (low ~ /^#+[[:space:]]*expected[[:space:]]*$/) { insec = 1; next }
      if (insec) exit
    }
    insec { print }
  ' "$1"
}

# --- extract the first table under the (case-insensitive) heading ----------
TABLE="$(awk '
  /^#{1,6}[[:space:]]/ {
    h = $0; sub(/^#+[[:space:]]*/, "", h); sub(/[[:space:]]+$/, "", h)
    if (tolower(h) == "e2e scenario cards") { insec = 1; next }
    if (insec) exit
  }
  insec && /^[[:space:]]*\|/ { intable = 1; print; next }
  insec && intable { exit }
' "$SPEC")"

if [ -z "$TABLE" ]; then
  echo "no scenario table: $SPEC has no \"E2E scenario cards\" heading with a table under it" >&2
  echo "(heading must be exactly \"E2E scenario cards\" — no numbering or extra words)" >&2
  exit 2
fi

# --- parse: protect escaped pipes, split rows into cells -------------------
US=$'\x1f'
CARD_COL=-1; FALS_COL=-1; ROWS=0
declare -a ROW_CARD ROW_FALS

lineno=0
while IFS= read -r line; do
  lineno=$((lineno + 1))
  esc="${line//\\|/$US}"
  IFS='|' read -r -a cells <<< "$esc"
  # drop leading/trailing empty fields produced by the outer pipes
  trimmed=()
  for c in "${cells[@]}"; do
    c="${c//$US/|}"
    c="$(printf '%s' "$c" | normalize)"
    trimmed+=("$c")
  done
  # cells[0] is empty (before first |); last may be empty too
  if [ "$lineno" -eq 1 ]; then
    for i in "${!trimmed[@]}"; do
      low="$(printf '%s' "${trimmed[$i]}" | tr '[:upper:]' '[:lower:]')"
      [ "$low" = "card" ] && CARD_COL=$i
      [ "$low" = "falsification" ] && FALS_COL=$i
    done
    continue
  fi
  # separator row: cells of dashes/colons only
  joined="$(printf '%s' "${trimmed[*]}" | tr -d ' :-')"
  [ -z "$joined" ] && continue
  if [ "$CARD_COL" -lt 0 ] || [ "$FALS_COL" -lt 0 ]; then
    fail "table header must name Card and Falsification columns"
    break
  fi
  card="${trimmed[$CARD_COL]:-}"
  falsif="${trimmed[$FALS_COL]:-}"
  card="${card//\`/}"          # tolerate `card-name` backticks in the cell
  if [ -z "$card" ] || [ -z "$falsif" ]; then
    fail "row $lineno: empty Card or Falsification cell"
    continue
  fi
  ROW_CARD[$ROWS]="$card"; ROW_FALS[$ROWS]="$falsif"; ROWS=$((ROWS + 1))
done <<< "$TABLE"

[ "$ROWS" -ge 1 ] || fail "scenario table has no data rows"

# --- checks 2-4 per row -----------------------------------------------------
i=0
while [ "$i" -lt "$ROWS" ]; do
  card="${ROW_CARD[$i]}"; falsif="${ROW_FALS[$i]}"
  f="$CARDS/$card.md"
  if [ ! -f "$f" ]; then
    fail "missing card file: $f"
    i=$((i + 1)); continue
  fi
  hay="$(expected_section "$f" | normalize)"
  case "$hay" in
    *"$falsif"*) : ;;
    *) fail "$f: falsification line not present verbatim in the ## Expected section.
       expected (normalized): $falsif" ;;
  esac
  grep -q '\*\*What this covers\*\*' "$f" || fail "$f: missing **What this covers**"
  for sec in Pre-state Steps Expected Cleanup; do
    grep -Eiq "^#{2,}[[:space:]]*${sec}[[:space:]]*$" "$f" || fail "$f: missing ## ${sec} section"
  done
  i=$((i + 1))
done

# --- check 5: extra cards are warnings --------------------------------------
for f in "$CARDS"/*.md; do
  [ -e "$f" ] || continue
  base="$(basename "$f" .md)"
  known=0; i=0
  while [ "$i" -lt "$ROWS" ]; do
    [ "${ROW_CARD[$i]}" = "$base" ] && known=1
    i=$((i + 1))
  done
  [ "$known" -eq 1 ] || warn "extra card not in spec table: $base"
done

if [ "$FAILURES" -gt 0 ]; then
  echo "$FAILURES check(s) failed"
  exit 1
fi
echo "all checks passed ($ROWS card(s))"