#!/usr/bin/env bash
# =============================================================================
# 法规知识库完整备份脚本 (backup_regulations.sh)
#
# 作用:
#   1. 检查共享基础设施容器 shuimu-kb-shared 与数据库状态；
#   2. 采用 pg_dump -Fc 高压缩二进制格式导出 regulations 数据库（含向量与索引）；
#   3. 镜像备份项目根目录的 .regulations 物理文件（支持目录克隆/同步及 tar 归档）；
#   4. 生成 manifest.json 记录基准元数据、统计指标及 SHA256 签名。
#
# 用法:
#   ./scripts/backup_regulations.sh <目标备份目录> [选项]
#
# 选项:
#   --archive, -a   额外将 .regulations 打包为 regulations_files.tar.gz
#   --help, -h      显示帮助信息
# =============================================================================

set -eo pipefail

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

CONTAINER_NAME="shuimu-kb-shared"
DB_NAME="regulations"
DB_USER="regkb"

show_help() {
    cat <<EOF
用法:
    $0 <目标备份目录> [选项]

参数:
    目标备份目录       必须指定，备份文件将保存至该目录下

选项:
    --archive, -a     额外将 .regulations 打包为 regulations_files.tar.gz 压缩包
    --help, -h        显示本帮助信息

示例:
    $0 /Volumes/Backups/regulations_20260911
    $0 ./backups/reg_backup --archive
EOF
    exit 0
}

if [[ $# -lt 1 ]]; then
    show_help
fi

TARGET_DIR=""
ARCHIVE_MODE=0

while [[ $# -gt 0 ]]; do
    case "$1" in
        --help|-h)
            show_help
            ;;
        --archive|-a)
            ARCHIVE_MODE=1
            shift
            ;;
        *)
            if [[ -z "${TARGET_DIR}" ]]; then
                TARGET_DIR="$1"
            else
                echo "[错误] 未知参数: $1"
                show_help
            fi
            shift
            ;;
    esac
done

if [[ -z "${TARGET_DIR}" ]]; then
    echo "[错误] 请指定目标备份目录！"
    exit 1
fi

# 解析绝对路径
mkdir -p "${TARGET_DIR}"
TARGET_DIR="$(cd "${TARGET_DIR}" && pwd)"

echo "============================================================"
echo ">>> 开始执行法规知识库完整备份"
echo ">>> 项目根路径: ${ROOT_DIR}"
echo ">>> 目标备份目录: ${TARGET_DIR}"
echo "============================================================"

# 1. 检查环境与 Docker 容器
if ! command -v docker >/dev/null 2>&1; then
    echo "[错误] 未找到 docker 命令，请先安装或启动 Docker！"
    exit 1
fi

if ! docker ps --format '{{.Names}}' | grep -q "^${CONTAINER_NAME}$"; then
    echo "[警告] 容器 ${CONTAINER_NAME} 未运行，尝试启动共享基础设施..."
    if [[ -f "${ROOT_DIR}/scripts/env-service.sh" ]]; then
        "${ROOT_DIR}/scripts/env-service.sh" shared start
    else
        docker compose -f "${ROOT_DIR}/docker-compose.shared.yml" up -d
    fi
fi

# 等待数据库就绪
echo "[等待] 检查数据库连接状态..."
for i in {1..30}; do
    if docker exec -i "${CONTAINER_NAME}" pg_isready -U "${DB_USER}" -d "${DB_NAME}" >/dev/null 2>&1; then
        echo "[就绪] 数据库连接正常。"
        break
    fi
    sleep 1
    if [ "$i" -eq 30 ]; then
        echo "[错误] 数据库连接超时，备份中止！"
        exit 1
    fi
done

# 2. 检查 .regulations 物理目录
REG_SOURCE_DIR="${ROOT_DIR}/.regulations"
if [[ ! -d "${REG_SOURCE_DIR}" ]]; then
    echo "[错误] 项目根目录下未找到 .regulations 目录 (${REG_SOURCE_DIR})！"
    exit 1
fi

# 3. 统计数据库基准指标
echo "[统计] 采集数据库元数据与统计指标..."
DOC_COUNT=$(docker exec -i "${CONTAINER_NAME}" psql -U "${DB_USER}" -d "${DB_NAME}" -t -A -c "SELECT count(*) FROM reg_documents;" 2>/dev/null || echo "0")
CHUNK_COUNT=$(docker exec -i "${CONTAINER_NAME}" psql -U "${DB_USER}" -d "${DB_NAME}" -t -A -c "SELECT count(*) FROM reg_chunks;" 2>/dev/null || echo "0")
NODE_COUNT=$(docker exec -i "${CONTAINER_NAME}" psql -U "${DB_USER}" -d "${DB_NAME}" -t -A -c "SELECT count(*) FROM reg_nodes;" 2>/dev/null || echo "0")
DB_SIZE=$(docker exec -i "${CONTAINER_NAME}" psql -U "${DB_USER}" -d "${DB_NAME}" -t -A -c "SELECT pg_size_pretty(pg_database_size('${DB_NAME}'));" 2>/dev/null || echo "0 MB")

echo "  • 法规文档数 (reg_documents): ${DOC_COUNT}"
echo "  • 法规切片数 (reg_chunks):   ${CHUNK_COUNT}"
echo "  • 大纲节点数 (reg_nodes):    ${NODE_COUNT}"
echo "  • 数据库当前体积:            ${DB_SIZE}"

# 4. 导出数据库
DUMP_FILENAME="regulations_db.dump"
TMP_CONTAINER_DUMP="/tmp/${DUMP_FILENAME}"
DEST_DUMP_PATH="${TARGET_DIR}/${DUMP_FILENAME}"

echo "[导出] 正在执行 PostgreSQL 数据库导出 (pg_dump -Fc 高压缩格式)..."
START_TIME=$(date +%s)
docker exec "${CONTAINER_NAME}" pg_dump -U "${DB_USER}" -d "${DB_NAME}" -Fc -Z 6 -f "${TMP_CONTAINER_DUMP}"
docker cp "${CONTAINER_NAME}:${TMP_CONTAINER_DUMP}" "${DEST_DUMP_PATH}"
docker exec "${CONTAINER_NAME}" rm -f "${TMP_CONTAINER_DUMP}"
DUMP_DURATION=$(( $(date +%s) - START_TIME ))

DUMP_SIZE_HUMAN=$(ls -lh "${DEST_DUMP_PATH}" | awk '{print $5}')
DUMP_SIZE_BYTES=$(stat -f "%z" "${DEST_DUMP_PATH}" 2>/dev/null || stat -c "%s" "${DEST_DUMP_PATH}" 2>/dev/null || echo "0")

echo "[完成] 数据库导出成功，耗时: ${DUMP_DURATION} 秒，体积: ${DUMP_SIZE_HUMAN}"

# 计算哈希
echo "[校验] 计算数据库 Dump 文件的 SHA256 校验和..."
if command -v shasum >/dev/null 2>&1; then
    DUMP_SHA256=$(shasum -a 256 "${DEST_DUMP_PATH}" | awk '{print $1}')
elif command -v sha256sum >/dev/null 2>&1; then
    DUMP_SHA256=$(sha256sum "${DEST_DUMP_PATH}" | awk '{print $1}')
else
    DUMP_SHA256="unavailable"
fi
echo "  • SHA256: ${DUMP_SHA256}"

# 5. 备份物理目录 .regulations
echo "[备份] 正在同步 .regulations 物理文档与解析工作区..."
DEST_REG_DIR="${TARGET_DIR}/.regulations"
mkdir -p "${DEST_REG_DIR}"

# 统计原文件数量与体积
TOTAL_FILES=$(find "${REG_SOURCE_DIR}" -type f | wc -l | tr -d ' ')
DIR_SIZE_HUMAN=$(du -sh "${REG_SOURCE_DIR}" | awk '{print $1}')

echo "  • 源文件总量: ${TOTAL_FILES} 个"
echo "  • 目录总大小: ${DIR_SIZE_HUMAN}"

# 优先使用 macOS APFS clonefile (快速且零物理块拷贝)
if cp -R -p -c "${REG_SOURCE_DIR}/." "${DEST_REG_DIR}/" 2>/dev/null; then
    echo "[完成] 已通过 APFS Copy-on-Write (零额外空间) 完成物理目录克隆镜像。"
else
    # 跨磁盘或非 APFS 降级为 rsync / cp
    if command -v rsync >/dev/null 2>&1; then
        rsync -a --delete "${REG_SOURCE_DIR}/" "${DEST_REG_DIR}/"
    else
        cp -R -p "${REG_SOURCE_DIR}/." "${DEST_REG_DIR}/"
    fi
    echo "[完成] 物理目录同步完成。"
fi

ARCHIVE_TAR_FILE=""
ARCHIVE_TAR_SHA256=""
if [[ "${ARCHIVE_MODE}" -eq 1 ]]; then
    echo "[归档] 正在将 .regulations 物理目录打包为 tar.gz..."
    ARCHIVE_TAR_FILE="regulations_files.tar.gz"
    ARCHIVE_TAR_PATH="${TARGET_DIR}/${ARCHIVE_TAR_FILE}"
    tar -czf "${ARCHIVE_TAR_PATH}" -C "${ROOT_DIR}" .regulations
    if command -v shasum >/dev/null 2>&1; then
        ARCHIVE_TAR_SHA256=$(shasum -a 256 "${ARCHIVE_TAR_PATH}" | awk '{print $1}')
    fi
    echo "[完成] 归档包已生成: ${ARCHIVE_TAR_PATH}"
fi

# 6. 生成元数据清单 manifest.json
MANIFEST_FILE="${TARGET_DIR}/manifest.json"
echo "[元数据] 写入备份清单 ${MANIFEST_FILE}..."
NOW_ISO=$(date -u +"%Y-%m-%dT%H:%M:%SZ")
HOSTNAME_STR=$(hostname 2>/dev/null || echo "unknown")

cat <<EOF > "${MANIFEST_FILE}"
{
  "manifest_version": "1.0",
  "created_at": "${NOW_ISO}",
  "project": "Chat-Agent-System",
  "source_hostname": "${HOSTNAME_STR}",
  "database": {
    "container_name": "${CONTAINER_NAME}",
    "database_name": "${DB_NAME}",
    "user": "${DB_USER}",
    "dump_file": "${DUMP_FILENAME}",
    "dump_sha256": "${DUMP_SHA256}",
    "dump_size_bytes": ${DUMP_SIZE_BYTES},
    "dump_size_human": "${DUMP_SIZE_HUMAN}",
    "document_count": ${DOC_COUNT},
    "chunk_count": ${CHUNK_COUNT},
    "node_count": ${NODE_COUNT},
    "database_size": "${DB_SIZE}"
  },
  "regulations_files": {
    "relative_path": ".regulations",
    "total_files": ${TOTAL_FILES},
    "directory_size": "${DIR_SIZE_HUMAN}",
    "subdirectories": [
      "intake",
      "library",
      "quarantine",
      "work"
    ],
    "archive_file": "${ARCHIVE_TAR_FILE}",
    "archive_sha256": "${ARCHIVE_TAR_SHA256}"
  }
}
EOF

echo "============================================================"
echo ">>> [SUCCESS] 法规知识库完整备份成功！"
echo ">>> 备份清单: ${MANIFEST_FILE}"
echo ">>> 数据库 Dump: ${DEST_DUMP_PATH} (${DUMP_SIZE_HUMAN})"
echo ">>> 物理文件目录: ${DEST_REG_DIR} (${TOTAL_FILES} 文件)"
if [[ -n "${ARCHIVE_TAR_FILE}" ]]; then
    echo ">>> 物理文件归档: ${TARGET_DIR}/${ARCHIVE_TAR_FILE}"
fi
echo "============================================================"
echo "恢复提示: 在任意目标机器上拉取本工程后，只需执行:"
echo "    ./scripts/restore_regulations.sh \"${TARGET_DIR}\""
echo "============================================================"