#!/usr/bin/env bash
# ============================================================
# dump_mysql_schema.sh
# ------------------------------------------------------------
# 导出 MySQL 整库（或指定库）的纯 DDL 到 stdout。
# 目的：把线上生产数据库的"表结构"抓回来，与 docs/sql/init_database.sql 做 diff。
#
# 适用场景（任选其一）：
#   1) 宿主机直接执行（远程 MySQL 同样可用，只要本机能连过去）
#   2) 容器内执行：
#        docker exec -i txw-mysql bash -s < devops/dump_mysql_schema.sh \
#          > prod_schema_$(date +%Y%m%d).sql
#
# 用法示例（远程库）：
#   MYSQL_HOST=192.168.110.55 MYSQL_PORT=3306 \
#   MYSQL_USER=root MYSQL_PWD='your_password' \
#   INCLUDE_DBS=qyd_txw \
#   bash devops/dump_mysql_schema.sh > qyd_txw_schema_$(date +%Y%m%d).sql
#
# 可调环境变量（全部可选）：
#   MYSQL_HOST           远端/本机地址（默认 localhost）
#   MYSQL_PORT           端口（默认 3306）
#   MYSQL_USER           用户名（默认 root）
#   MYSQL_PWD            密码（推荐用单引号包裹，避免 $、! 等被 bash 解释）
#   INCLUDE_DBS          只导指定库，多个用逗号分隔；留空=全部业务库
#   EXCLUDE_DBS          排除的库（默认：information_schema,performance_schema,mysql,sys）
# ============================================================

set -euo pipefail

# ---------- 默认值（与 devops/docker-compose.infra.prod.yml 保持一致） ----------
MYSQL_USER="${MYSQL_USER:-root}"
MYSQL_PWD="${MYSQL_PWD:-MysqlRootPwd@2024#Secure}"
MYSQL_HOST="${MYSQL_HOST:-localhost}"
MYSQL_PORT="${MYSQL_PORT:-3306}"
EXCLUDE_DBS="${EXCLUDE_DBS:-information_schema,performance_schema,mysql,sys}"
INCLUDE_DBS="${INCLUDE_DBS:-}"

# 容器内不落盘：所有 SQL 走 stdout 流到宿主机，容器内零残留。

# ---------- 工具自检 ----------
for bin in mysql mysqldump; do
  if ! command -v "$bin" >/dev/null 2>&1; then
    echo "[FATAL] 当前环境找不到 $bin，请先安装 mysql-client（apt: default-mysql-client / yum: mysql / dnf: mysql）" >&2
    exit 1
  fi
done

# 把密码通过 MYSQL_PWD 环境变量传给客户端，避免命令行泄露
export MYSQL_PWD

log()  { echo "[$(date '+%H:%M:%S')] $*" >&2; }
fail() { echo "[FATAL] $*" >&2; exit 1; }

# ---------- 1. 连通性自检 ----------
log "自检：尝试连接 ${MYSQL_USER}@${MYSQL_HOST}:${MYSQL_PORT} ..."
if ! mysql -h "$MYSQL_HOST" -P "$MYSQL_PORT" -u "$MYSQL_USER" \
      -e "SELECT VERSION();" >/dev/null 2>&1; then
  fail "无法连接 MySQL，请检查账号/密码/网络"
fi
VERSION=$(mysql -h "$MYSQL_HOST" -P "$MYSQL_PORT" -u "$MYSQL_USER" -N -B \
  -e "SELECT VERSION();" 2>/dev/null)
log "连接成功，MySQL 版本: ${VERSION}"

# ---------- 2. 列出要导出的库 ----------
if [ -n "$INCLUDE_DBS" ]; then
  # 把逗号分隔的 INCLUDE_DBS 变成 SQL IN (...) 列表
  IN_CLAUSE=$(printf "%s" "$INCLUDE_DBS" | awk -F',' '{
    out=""; for (i=1;i<=NF;i++){ gsub(/^ +| +$/,"",$i); out=out"'\''"$i"'\''," }
    sub(/,$/,"",out); print out
  }')
  DB_LIST=$(mysql -h "$MYSQL_HOST" -P "$MYSQL_PORT" -u "$MYSQL_USER" -N -B -e \
    "SELECT SCHEMA_NAME FROM information_schema.SCHEMATA
       WHERE SCHEMA_NAME IN ($IN_CLAUSE) ORDER BY SCHEMA_NAME;" 2>/dev/null)
else
  # 用 NOT REGEXP 排除系统库
  EXCLUDED_REGEX=$(printf "%s" "$EXCLUDE_DBS" | sed 's/,/|/g')
  DB_LIST=$(mysql -h "$MYSQL_HOST" -P "$MYSQL_PORT" -u "$MYSQL_USER" -N -B -e \
    "SELECT SCHEMA_NAME FROM information_schema.SCHEMATA
       WHERE SCHEMA_NAME NOT REGEXP '$EXCLUDED_REGEX'
       ORDER BY SCHEMA_NAME;" 2>/dev/null)
fi

if [ -z "$DB_LIST" ]; then
  fail "未找到任何目标库（INCLUDE_DBS='${INCLUDE_DBS}', EXCLUDE_DBS='${EXCLUDE_DBS}'）"
fi

log "将导出以下库: $(echo $DB_LIST | tr '\n' ' ')"

# ---------- 3. 写文件头（直写 stdout，不落盘） ----------
echo "-- ============================================================"
echo "-- MySQL 整库 DDL 导出"
echo "-- 数据库版本: ${VERSION}"
echo "-- 生成时间 : $(date '+%Y-%m-%d %H:%M:%S %z')"
echo "-- 目标库   : $(echo $DB_LIST | tr '\n' ',' | sed 's/,$//')"
echo "-- 生成方式 : mysqldump --no-data（仅结构，不含数据）"
echo "-- ============================================================"
echo "SET NAMES utf8mb4;"
echo "SET FOREIGN_KEY_CHECKS = 0;"

# ---------- 4. 逐库 dump（直接 echo 到 stdout） ----------
TOTAL_TABLES=0
TOTAL_VIEWS=0

for DB in $DB_LIST; do
  log "==> 导出库 [$DB]"

  echo ""
  echo "-- ----------------------------"
  echo "-- Database: ${DB}"
  echo "-- ----------------------------"
  echo "USE \`${DB}\`;"

  # 取表列表
  TABLES=$(mysql -h "$MYSQL_HOST" -P "$MYSQL_PORT" -u "$MYSQL_USER" -N -B -e \
    "SELECT TABLE_NAME FROM information_schema.TABLES
       WHERE TABLE_SCHEMA='${DB}' AND TABLE_TYPE='BASE TABLE'
       ORDER BY TABLE_NAME;" 2>/dev/null)

  for TBL in $TABLES; do
    echo "DROP TABLE IF EXISTS \`${TBL}\`;"
    mysqldump -h "$MYSQL_HOST" -P "$MYSQL_PORT" -u "$MYSQL_USER" \
      --no-data --skip-comments --skip-add-locks \
      --skip-lock-tables --skip-disable-keys \
      --skip-tz-utc --set-gtid-purged=OFF \
      --default-character-set=utf8mb4 \
      --compact --skip-add-drop-table \
      "${DB}" "${TBL}" 2>/dev/null
    echo ";"
    echo ""
    TOTAL_TABLES=$((TOTAL_TABLES + 1))
  done

  # 取视图列表
  VIEWS=$(mysql -h "$MYSQL_HOST" -P "$MYSQL_PORT" -u "$MYSQL_USER" -N -B -e \
    "SELECT TABLE_NAME FROM information_schema.VIEWS
       WHERE TABLE_SCHEMA='${DB}' ORDER BY TABLE_NAME;" 2>/dev/null || true)

  for VW in $VIEWS; do
    echo "DROP VIEW IF EXISTS \`${VW}\`;"
    mysqldump -h "$MYSQL_HOST" -P "$MYSQL_PORT" -u "$MYSQL_USER" \
      --no-data --skip-comments --skip-add-locks \
      --skip-lock-tables --skip-disable-keys \
      --set-gtid-purged=OFF \
      --default-character-set=utf8mb4 \
      --compact --skip-add-drop-table \
      "${DB}" "${VW}" 2>/dev/null
    echo ";"
    echo ""
    TOTAL_VIEWS=$((TOTAL_VIEWS + 1))
  done
done

# ---------- 5. 文件尾 ----------
echo ""
echo "SET FOREIGN_KEY_CHECKS = 1;"

# 统计日志走 stderr，不会污染 stdout 上的 SQL 文件
log "导出完成：表 ${TOTAL_TABLES} 个，视图 ${TOTAL_VIEWS} 个"