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

# CASAN Level 5 rollback transaction recorder.
# Usage:
#   rollback-manager.sh record <action> <rollback-command>
#   rollback-manager.sh checkpoint <file>     # back up a file; records a REAL restore command
#   rollback-manager.sh execute <transaction-id>

MODE="${1:-}"
ACTION="${2:-}"
ROLLBACK_COMMAND="${3:-}"

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="$(cd "$SCRIPT_DIR/../../.." && pwd)"
LOG_DIR="$PROJECT_ROOT/.specify/logs/level5"
BACKUP_DIR="$LOG_DIR/rollback-backups"
TX_LOG="$LOG_DIR/rollback-transactions.jsonl"
mkdir -p "$LOG_DIR" "$BACKUP_DIR"

# checkpoint: snapshot a real file and record a real restore command so a later
# `execute` genuinely undoes any change (not a marker write).
if [[ "$MODE" == "checkpoint" ]]; then
  TARGET="$ACTION"
  if [[ -z "$TARGET" || ! -f "$TARGET" ]]; then
    echo "Usage: rollback-manager.sh checkpoint <existing-file>" >&2
    exit 64
  fi
  TX_ID="$(uuidgen 2>/dev/null | tr '[:upper:]' '[:lower:]' || printf 'tx-%s-%s' "$(date +%s)" "$$")"
  BACKUP="$BACKUP_DIR/$TX_ID.bak"
  cp "$TARGET" "$BACKUP"
  ABS_TARGET="$(cd "$(dirname "$TARGET")" && pwd)/$(basename "$TARGET")"
  RESTORE_CMD="cp '$BACKUP' '$ABS_TARGET'"
  TIMESTAMP="$(date -u +"%Y-%m-%dT%H:%M:%SZ")"
  python - "$TX_LOG" "$TIMESTAMP" "$TX_ID" "$ABS_TARGET" "$RESTORE_CMD" "$BACKUP" <<'PY'
import json, sys
log, ts, tx, target, cmd, backup = sys.argv[1:]
rec = {"timestamp": ts, "transaction_id": tx, "action": "checkpoint",
       "target": target, "backup": backup, "rollback_command": cmd, "status": "recorded"}
open(log, "a", encoding="utf-8").write(json.dumps(rec) + "\n")
PY
  echo "ROLLBACK_CHECKPOINT transaction_id=$TX_ID target=$ABS_TARGET"
  exit 0
fi

if [[ "$MODE" == "record" ]]; then
  if [[ -z "$ACTION" || -z "$ROLLBACK_COMMAND" ]]; then
    echo "Usage: rollback-manager.sh record <action> <rollback-command>" >&2
    exit 64
  fi
  TX_ID="$(uuidgen 2>/dev/null | tr '[:upper:]' '[:lower:]' || printf 'tx-%s-%s' "$(date +%s)" "$$")"
  TIMESTAMP="$(date -u +"%Y-%m-%dT%H:%M:%SZ")"
  printf '{"timestamp":"%s","transaction_id":"%s","action":"%s","rollback_command":"%s","status":"recorded"}\n' \
    "$TIMESTAMP" "$TX_ID" "$ACTION" "$ROLLBACK_COMMAND" >> "$TX_LOG"
  echo "ROLLBACK_RECORDED transaction_id=$TX_ID"
  exit 0
fi

if [[ "$MODE" == "execute" ]]; then
  TX_ID="$ACTION"
  if [[ -z "$TX_ID" || ! -f "$TX_LOG" ]]; then
    echo "ROLLBACK_NOT_FOUND transaction_id=$TX_ID" >&2
    exit 1
  fi
  COMMAND="$(python - "$TX_LOG" "$TX_ID" <<'PY'
import json, sys
for line in open(sys.argv[1], encoding="utf-8"):
    rec=json.loads(line)
    if rec.get("transaction_id")==sys.argv[2]:
        print(rec.get("rollback_command",""))
        break
PY
)"
  if [[ -z "$COMMAND" ]]; then
    echo "ROLLBACK_NOT_FOUND transaction_id=$TX_ID" >&2
    exit 1
  fi
  bash -c "$COMMAND"
  TIMESTAMP="$(date -u +"%Y-%m-%dT%H:%M:%SZ")"
  printf '{"timestamp":"%s","transaction_id":"%s","status":"rolled_back"}\n' "$TIMESTAMP" "$TX_ID" >> "$TX_LOG"
  echo "ROLLBACK_EXECUTED transaction_id=$TX_ID"
  exit 0
fi

echo "Usage: rollback-manager.sh record|execute ..." >&2
exit 64