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

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
ROOT_DIR="$(cd "${SCRIPT_DIR}/../.." && pwd)"

load_database_url_from_env_file() {
  local env_file="$1"
  local line value
  while IFS= read -r line || [[ -n "${line}" ]]; do
    line="${line#"${line%%[![:space:]]*}"}"
    [[ -z "${line}" || "${line}" == \#* ]] && continue
    line="${line#export }"
    if [[ "${line}" == DATABASE_URL=* ]]; then
      value="${line#DATABASE_URL=}"
      value="${value%$'\r'}"
      value="${value%\"}"
      value="${value#\"}"
      value="${value%\'}"
      value="${value#\'}"
      printf '%s' "${value}"
      return 0
    fi
  done < "${env_file}"
  return 1
}

DATABASE_URL="${DATABASE_URL:-}"
if [[ -z "${DATABASE_URL}" && -f "${ROOT_DIR}/.env" ]]; then
  DATABASE_URL="$(load_database_url_from_env_file "${ROOT_DIR}/.env" || true)"
fi
if [[ -z "${DATABASE_URL}" ]]; then
  echo "DATABASE_URL is required (export it, or set it in ${ROOT_DIR}/.env)"
  exit 1
fi

if ! command -v psql >/dev/null 2>&1; then
  echo "psql not found in PATH"
  exit 127
fi

CONFIRM="${CONFIRM:-0}"
if [[ "${CONFIRM}" != "1" ]]; then
  echo "Refusing to run rollback without CONFIRM=1"
  exit 1
fi

TARGET_VERSION="${TARGET_VERSION:-}"
STEPS="${STEPS:-1}"

if ! psql "${DATABASE_URL}" -v ON_ERROR_STOP=1 -c "SELECT 1 FROM iam_schema_migrations LIMIT 1" >/dev/null 2>&1; then
  echo "No iam_schema_migrations table found; nothing to rollback"
  exit 0
fi

applied_versions=()
while IFS= read -r v; do
  [[ -n "${v}" ]] && applied_versions+=( "${v}" )
done < <(psql "${DATABASE_URL}" -At -c "SELECT version FROM iam_schema_migrations ORDER BY version DESC")

if [[ ${#applied_versions[@]} -eq 0 ]]; then
  echo "No applied migrations; nothing to rollback"
  exit 0
fi

to_rollback=()
if [[ -n "${TARGET_VERSION}" ]]; then
  for v in "${applied_versions[@]}"; do
    if [[ "${v}" > "${TARGET_VERSION}" ]]; then
      to_rollback+=( "${v}" )
    fi
  done
else
  count=0
  for v in "${applied_versions[@]}"; do
    to_rollback+=( "${v}" )
    count=$((count + 1))
    if [[ "${count}" -ge "${STEPS}" ]]; then
      break
    fi
  done
fi

if [[ ${#to_rollback[@]} -eq 0 ]]; then
  echo "No migrations to rollback"
  exit 0
fi

for v in "${to_rollback[@]}"; do
  down_file="${SCRIPT_DIR}/rollback/${v}.down.sql"
  if [[ ! -f "${down_file}" ]]; then
    echo "Missing rollback script: ${down_file}"
    exit 1
  fi
  echo "Rolling back ${v}"
  psql "${DATABASE_URL}" -v ON_ERROR_STOP=1 -f "${down_file}"
  psql "${DATABASE_URL}" -v ON_ERROR_STOP=1 -c "DELETE FROM iam_schema_migrations WHERE version='${v}'"
done

echo "Rollback completed"