#!/usr/bin/env bash
# ==============================================================================
# db_log_exporter — 安装部署脚本
# ==============================================================================
# 用法:
#   sudo ./setup.sh [install | uninstall | status]
#
# 支持: CentOS 7/8, RHEL, Fedora, Debian, Ubuntu
# ==============================================================================

set -euo pipefail

APP_NAME="db_log_exporter"
INSTALL_DIR="/opt/${APP_NAME}"
CONFIG_DIR="/etc/${APP_NAME}"
SYSTEMD_UNIT="${APP_NAME}.service"
LOG_DIR="/var/log/${APP_NAME}"
DATA_DIR="/var/lib/${APP_NAME}"
RUN_DIR="/var/run/${APP_NAME}"
CHECKPOINT_DIR="${DATA_DIR}/checkpoints"

# 颜色
RED='\033[0;31m'; GREEN='\033[0;32m'; YELLOW='\033[1;33m'; NC='\033[0m'

info()    { echo -e "${GREEN}[INFO]${NC}  $*"; }
warn()    { echo -e "${YELLOW}[WARN]${NC}  $*" >&2; }
error()   { echo -e "${RED}[ERROR]${NC} $*" >&2; exit 1; }
need_root() { [ "$(id -u)" -eq 0 ] || error "请用 root 权限运行: sudo $0 $*"; }

# ---------------------------------------------------------------------------
# 检查依赖
# ---------------------------------------------------------------------------
check_deps() {
    info "检查依赖..."
    local missing=()

    if ! command -v python3 &>/dev/null; then
        missing+=("python3")
    fi

    if ! python3 -c "import pymysql" 2>/dev/null; then
        missing+=("PyMySQL (pip3 install pymysql)")
    fi
    if ! python3 -c "import psycopg2" 2>/dev/null; then
        missing+=("psycopg2-binary (pip3 install psycopg2-binary)")
    fi
    if ! python3 -c "import yaml" 2>/dev/null; then
        missing+=("PyYAML (pip3 install pyyaml)")
    fi

    if [ ${#missing[@]} -gt 0 ]; then
        error "缺少依赖: ${missing[*]} \n请先安装: pip3 install PyMySQL psycopg2-binary PyYAML"
    fi

    # 检查 MySQL / PostgreSQL 客户端(仅检查命令是否存在，不强制要求服务运行)
    if command -v mysql &>/dev/null || command -v psql &>/dev/null; then
        info "数据库客户端已找到"
    else
        warn "未找到 mysql/psql 客户端(程序使用 Python DB 驱动，不影响运行)"
    fi

    info "依赖检查通过 ✓"
}

# ---------------------------------------------------------------------------
# 安装
# ---------------------------------------------------------------------------
do_install() {
    need_root "$@"
    check_deps

    info "开始安装 ${APP_NAME}..."

    # 1. 创建目录
    for d in "${INSTALL_DIR}" "${CONFIG_DIR}" "${LOG_DIR}" "${DATA_DIR}" "${CHECKPOINT_DIR}" "${RUN_DIR}"; do
        mkdir -p "$d"
        echo "  创建: $d"
    done

    # 2. 复制文件
    cp "$(dirname "$0")/db_log_exporter.py"  "${INSTALL_DIR}/"
    cp "$(dirname "$0")/config.yaml"          "${CONFIG_DIR}/config.yaml.example"
    [ -f "$(dirname "$0")/requirements.txt" ] && \
        cp "$(dirname "$0")/requirements.txt" "${INSTALL_DIR}/"

    info "文件已复制到 ${INSTALL_DIR} 和 ${CONFIG_DIR}"

    # 3. 创建 config.yaml(如果不存在)
    if [ ! -f "${CONFIG_DIR}/config.yaml" ]; then
        if [ -f "${CONFIG_DIR}/config.yaml.example" ]; then
            cp "${CONFIG_DIR}/config.yaml.example" "${CONFIG_DIR}/config.yaml"
            warn "已创建默认配置: ${CONFIG_DIR}/config.yaml"
            warn "请编辑配置文件，填入数据库连接信息后再启动服务！"
        fi
    fi

    # 4. 安装 systemd 服务
    local systemd_dir="/etc/systemd/system"
    cp "$(dirname "$0")/${SYSTEMD_UNIT}" "${systemd_dir}/"
    chmod 644 "${systemd_dir}/${SYSTEMD_UNIT}"
    systemctl daemon-reload

    info "systemd 服务已安装 ✓"
    info ""
    info "=== 后续步骤 ==="
    info "1. 编辑配置:   nano ${CONFIG_DIR}/config.yaml"
    info "2. 检查连接:   python3 ${INSTALL_DIR}/${APP_NAME}.py -c ${CONFIG_DIR}/config.yaml --dry-run"
    info "3. 启动服务:   systemctl start  ${APP_NAME}"
    info "4. 开机自启:  systemctl enable ${APP_NAME}"
    info "5. 查看日志:  journalctl -u ${APP_NAME} -f"
    info ""
    info "安装完成 ✓"
}

# ---------------------------------------------------------------------------
# 卸载
# ---------------------------------------------------------------------------
do_uninstall() {
    need_root "$@"

    info "停止并禁用服务..."
    systemctl stop   "${APP_NAME}"  2>/dev/null || true
    systemctl disable "${APP_NAME}"  2>/dev/null || true

    info "删除 systemd unit..."
    rm -f "/etc/systemd/system/${SYSTEMD_UNIT}"
    systemctl daemon-reload

    info "删除安装目录(确认不再需要)..."
    read -rp "是否删除 ${INSTALL_DIR} 和 ${CONFIG_DIR}？[y/N]: " confirm
    if [[ "$confirm" =~ ^[Yy]$ ]]; then
        rm -rf "${INSTALL_DIR}" "${CONFIG_DIR}" "${LOG_DIR}" "${DATA_DIR}" "${RUN_DIR}"
        info "已删除所有文件 ✓"
    else
        warn "保留文件，手动清理: rm -rf ${INSTALL_DIR} ${CONFIG_DIR}"
    fi
}

# ---------------------------------------------------------------------------
# 状态
# ---------------------------------------------------------------------------
do_status() {
    if systemctl is-active --quiet "${APP_NAME}"; then
        info "服务状态: 运行中 ✓"
        systemctl status "${APP_NAME}" --no-pager
    elif systemctl is-enabled --quiet "${APP_NAME}"; then
        warn "服务状态: 未运行(已开机自启)"
    else
        warn "服务状态: 未安装或未启用"
    fi

    if [ -d "${CHECKPOINT_DIR}" ]; then
        echo ""
        info "断点文件:"
        ls -la "${CHECKPOINT_DIR}" 2>/dev/null | grep -v "^total" || echo "  (空)"
    fi

    if [ -d "${LOG_DIR}" ]; then
        echo ""
        info "日志文件:"
        ls -lh "${LOG_DIR}" 2>/dev/null || echo "  (空)"
    fi
}

# ---------------------------------------------------------------------------
# 主入口
# ---------------------------------------------------------------------------
ACTION="${1:-install}"

case "$ACTION" in
    install)   do_install   "$@" ;;
    uninstall) do_uninstall "$@" ;;
    status)   do_status    "$@" ;;
    *)        error "未知操作: $ACTION(支持: install | uninstall | status)" ;;
esac