#!/bin/sh
set -eu

ROOT_DIR=$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)
ENV_FILE=${ENV_FILE:-.env.production}
DB_SERVICE=${DB_SERVICE:-sori-studio-db}
MIGRATIONS_DIR="$ROOT_DIR/db/migrations"
CONTAINER_MIGRATIONS_DIR=${CONTAINER_MIGRATIONS_DIR:-/docker-entrypoint-initdb.d}
SCHEMA_MIGRATIONS_TABLE=${SCHEMA_MIGRATIONS_TABLE:-schema_migrations}
MODE=${1:-migrate}
BASELINE_TARGET=${2:-}

cd "$ROOT_DIR"

if [ -f "$ENV_FILE" ]; then
  set -a
  # shellcheck disable=SC1090
  . "$ENV_FILE"
  set +a
fi

POSTGRES_DB=${POSTGRES_DB:-sori_studio}
POSTGRES_USER=${POSTGRES_USER:-sori_studio}

compose() {
  docker compose --env-file "$ENV_FILE" "$@"
}

psql_exec() {
  compose exec -T "$DB_SERVICE" psql -v ON_ERROR_STOP=1 -U "$POSTGRES_USER" -d "$POSTGRES_DB" "$@"
}

query_sql() {
  psql_exec -At -c "$1" | tr -d '\r'
}

run_sql() {
  psql_exec -c "$1"
}

ensure_database_ready() {
  compose up -d "$DB_SERVICE"

  attempt=1
  while [ "$attempt" -le 20 ]; do
    if compose exec -T "$DB_SERVICE" pg_isready -U "$POSTGRES_USER" -d "$POSTGRES_DB" >/dev/null 2>&1; then
      return 0
    fi

    attempt=$((attempt + 1))
    sleep 1
  done

  echo "DB가 준비되지 않았습니다." >&2
  exit 1
}

has_schema_migrations_table() {
  [ "$(query_sql "SELECT to_regclass('public.$SCHEMA_MIGRATIONS_TABLE') IS NOT NULL;")" = "t" ]
}

has_application_schema() {
  [ "$(query_sql "SELECT to_regclass('public.posts') IS NOT NULL;")" = "t" ]
}

ensure_schema_migrations_table() {
  run_sql "CREATE TABLE IF NOT EXISTS $SCHEMA_MIGRATIONS_TABLE (
    file_name TEXT PRIMARY KEY,
    applied_at TIMESTAMPTZ NOT NULL DEFAULT now()
  );"
}

migration_files() {
  find "$MIGRATIONS_DIR" -maxdepth 1 -type f -name '*.sql' -exec basename {} \; | sort
}

is_applied() {
  file_name=$1
  [ "$(query_sql "SELECT EXISTS (SELECT 1 FROM $SCHEMA_MIGRATIONS_TABLE WHERE file_name = '$file_name');")" = "t" ]
}

print_status() {
  if ! has_schema_migrations_table; then
    echo "schema_migrations 테이블이 없습니다."
    echo "기존 운영 DB라면 먼저 sh scripts/migrate-production-db.sh baseline 으로 현재 파일들을 적용 완료로 기록하세요."

    migration_files | while IFS= read -r file_name; do
      echo "pending $file_name"
    done
    return 0
  fi

  migration_files | while IFS= read -r file_name; do
    if is_applied "$file_name"; then
      echo "applied $file_name"
    else
      echo "pending $file_name"
    fi
  done
}

baseline_migrations() {
  ensure_schema_migrations_table
  baseline_count=0
  found_target=0

  migration_files | while IFS= read -r file_name; do
    if [ -n "$BASELINE_TARGET" ] && [ "$found_target" -eq 1 ]; then
      continue
    fi

    run_sql "INSERT INTO $SCHEMA_MIGRATIONS_TABLE (file_name) VALUES ('$file_name') ON CONFLICT (file_name) DO NOTHING;"
    echo "baseline $file_name"
    baseline_count=$((baseline_count + 1))

    if [ -n "$BASELINE_TARGET" ] && { [ "$file_name" = "$BASELINE_TARGET" ] || echo "$file_name" | grep -q "^${BASELINE_TARGET}_"; }; then
      found_target=1
    fi
  done

  if [ -n "$BASELINE_TARGET" ] && ! migration_files | grep -q "^${BASELINE_TARGET}_\\|^${BASELINE_TARGET}$"; then
    echo "기준 마이그레이션을 찾을 수 없습니다: $BASELINE_TARGET" >&2
    exit 1
  fi

  echo "baseline 완료"
}

migrate_database() {
  if ! has_schema_migrations_table && has_application_schema; then
    echo "운영 DB에 기존 스키마가 있지만 schema_migrations 적용 이력이 없습니다." >&2
    echo "데이터 보호를 위해 001부터 자동 실행하지 않습니다." >&2
    echo "현재 운영 DB가 최신 상태라면 sh scripts/migrate-production-db.sh baseline 으로 기준점을 먼저 기록하세요." >&2
    echo "상태 확인: sh scripts/migrate-production-db.sh status" >&2
    exit 1
  fi

  ensure_schema_migrations_table
  applied_count=0

  migration_files | while IFS= read -r file_name; do
    if is_applied "$file_name"; then
      continue
    fi

    echo "apply $file_name"
    psql_exec -f "$CONTAINER_MIGRATIONS_DIR/$file_name"
    run_sql "INSERT INTO $SCHEMA_MIGRATIONS_TABLE (file_name) VALUES ('$file_name') ON CONFLICT (file_name) DO NOTHING;"
    applied_count=$((applied_count + 1))
  done

  echo "마이그레이션 실행 완료"
}

ensure_database_ready

case "$MODE" in
  status)
    print_status
    ;;
  baseline)
    baseline_migrations
    ;;
  migrate)
    migrate_database
    ;;
  *)
    echo "사용법: sh scripts/migrate-production-db.sh [status|baseline|migrate] [기준번호]" >&2
    exit 1
    ;;
esac