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

# CASAN Plan-17 Track 4 — Loop Trace / Replay.
#
# Proves:
#   * record appends hash-linked Iteration records (append-only),
#   * show renders the loop view (JSON on stdout),
#   * verify-chain confirms an intact chain (exit 0),
#   * editing a recorded record BREAKs the chain (exit 3),
#   * replay re-verifies recorded artifacts and MATCHes when unchanged,
#   * tampering a recorded artifact makes replay DRIFT (verdict mismatch, exit 3),
#   * a corrupt trace file fails closed (verify-chain BREAK),
#   * state redirected -> repo .specify/state stays clean.
#
# Deterministic; hermetic; H4 uses the offline pattern layer (no model / network).

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
TRACE="$PROJECT_ROOT/.specify/scripts/bash/loop-trace.py"

WORK="$(mktemp -d)"
trap 'rm -rf "$WORK"' EXIT
export CASAN_LOOP_STATE_ROOT="$WORK/state"
export CASAN_LOOP_POLICY_FILE="$WORK/no-policy.yaml"  # strict ceiling; not needed for trace

PASS=0; FAIL=0
pass() { echo "PASS: $1"; PASS=$((PASS + 1)); }
fail() { echo "FAIL: $1"; FAIL=$((FAIL + 1)); }

tr_cmd() {
  # tr_cmd <expect_rc> <desc> -- <args...>; stdout captured in $OUT
  local expect="$1"; shift
  local desc="$1"; shift
  [[ "$1" == "--" ]] && shift
  set +e
  OUT="$(python3 "$TRACE" "$@" 2>/dev/null)"
  local rc=$?
  set -e 2>/dev/null || true
  if [[ "$rc" -eq "$expect" ]]; then pass "$desc (rc=$rc)"; else fail "$desc (rc=$rc, want $expect)"; fi
}

echo "===== Plan-17 T4: Loop Trace / Replay ====="

# fixtures: a good artifact that meets criteria (loop-gate PASS)
printf 'REQ-01 persists OKR to the database. Dashboard renders 3 widgets.\n' > "$WORK/art1.txt"
printf '{"must_contain":["REQ-01","Dashboard"]}\n' > "$WORK/crit.json"

RUN=trace-run-1

# 1) record three iterations
tr_cmd 0 "record step 1" -- record --run-id "$RUN" --step 1 --intent "persist" \
  --action write --tool db --gate-verdict PASS --progress 0.3 --decision CONTINUE \
  --artifact "$WORK/art1.txt" --success-criteria "$WORK/crit.json"
tr_cmd 0 "record step 2" -- record --run-id "$RUN" --step 2 --intent "render" \
  --action ui --gate-verdict PASS --progress 0.6 --decision CONTINUE
tr_cmd 0 "record step 3" -- record --run-id "$RUN" --step 3 --intent "done" \
  --gate-verdict PASS --progress 1.0 --decision DONE

# 2) show -> JSON loop view with 3 iterations
tr_cmd 0 "show loop view" -- show --run-id "$RUN"
grep -q '"count": 3' <<<"$OUT" && pass "show reports 3 iterations" || fail "show wrong count"

# 3) verify-chain intact
tr_cmd 0 "verify-chain intact -> OK" -- verify-chain --run-id "$RUN"
grep -q '"decision": "OK"' <<<"$OUT" && pass "chain OK decision" || fail "chain not OK"

# 4) replay unchanged artifact -> MATCH
tr_cmd 0 "replay unchanged -> MATCH" -- replay --run-id "$RUN"
grep -q '"decision": "MATCH"' <<<"$OUT" && pass "replay MATCH" || fail "replay not MATCH"

# 5) tamper the recorded artifact -> replay DRIFT (recorded PASS, now FAIL)
printf 'unrelated content, requirement removed.\n' > "$WORK/art1.txt"
tr_cmd 3 "replay after artifact tamper -> DRIFT" -- replay --run-id "$RUN"
grep -q '"decision": "DRIFT"' <<<"$OUT" && pass "replay DRIFT on tamper" || fail "tamper not detected by replay"

# 6) tamper a trace record -> verify-chain BREAK
TRACE_FILE="$CASAN_LOOP_STATE_ROOT/runs/$RUN/trace.jsonl"
# flip the progress of the 2nd record without recomputing its hash
python3 - "$TRACE_FILE" <<'PY'
import json, sys
p=sys.argv[1]
lines=[l for l in open(p) if l.strip()]
e=json.loads(lines[1]); e["iteration"]["progress"]=0.999
lines[1]=json.dumps(e, sort_keys=True, ensure_ascii=False)+"\n"
open(p,"w").writelines(lines)
PY
tr_cmd 3 "edited record -> chain BREAK" -- verify-chain --run-id "$RUN"
grep -q '"reason": "chain_broken"' <<<"$OUT" && pass "chain_broken reason" || fail "chain break not reported"

# 7) corrupt trace file -> fail-closed BREAK
RUN2=trace-broken
mkdir -p "$CASAN_LOOP_STATE_ROOT/runs/$RUN2"
printf 'not-json{{{\n' > "$CASAN_LOOP_STATE_ROOT/runs/$RUN2/trace.jsonl"
tr_cmd 3 "corrupt trace -> fail-closed BREAK" -- verify-chain --run-id "$RUN2"
grep -q '"reason": "fail_closed"' <<<"$OUT" && pass "corrupt trace fails closed" || fail "corrupt trace not fail-closed"

# 8) no repo pollution
if [[ -d "$PROJECT_ROOT/.specify/state" ]] && [[ -n "$(ls -A "$PROJECT_ROOT/.specify/state" 2>/dev/null)" ]]; then
  fail "repo .specify/state was polluted"
else
  pass "repo .specify/state stays clean"
fi

echo ""
echo "===== T4 SUMMARY: PASS=$PASS FAIL=$FAIL ====="
[[ "$FAIL" -eq 0 ]] || exit 1