#!/bin/bash
# ===========================================
# 蓝绿切换脚本
# 切换生产环境 OpenResty proxy_pass 指向
# 实现零停机切换
# ===========================================

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
PROJECT_ROOT="$(dirname "$SCRIPT_DIR")"
ENV_FILE="$PROJECT_ROOT/.env"

# ---------- 配置 ----------
ROOT_CONF="/etc/nginx/sites-enabled/xmclassmate.top"
NGINX_SSL_CONF="/www/sites/xmclassmate.top/ssl/fullchain.pem"
SSH_HOST="deploy@47.109.203.92"

# ---------- 颜色输出 ----------
RED='\033[0;31m'; GREEN='\033[0;32m'; YELLOW='\033[1;33m'; BLUE='\033[0;34m'; NC='\033[0m'
info()  { echo -e "${GREEN}[INFO]${NC} $1"; }
warn()  { echo -e "${YELLOW}[WARN]${NC} $1"; }
error() { echo -e "${RED}[ERROR]${NC} $1" >&2; }

# ---------- 获取 SSH 主机 ----------
get_ssh_host() {
    grep '^SSH_SERVER=' "$ENV_FILE" 2>/dev/null | head -1 | cut -d'=' -f2- | tr -d '"' | tr -d "'" | xargs
}

# ---------- 使用说明 ----------
usage() {
    echo "用法: $0 [--status|--switch blue|green|--help]"
    echo ""
    echo "  --status             查看当前活动环境"
    echo "  --switch <blue|green> 切换到指定环境"
    echo "  --help               显示帮助"
    exit 0
}

# ---------- 获取当前活动环境 ----------
get_active() {
    local proxy_conf; proxy_conf=$(ssh "$SSH_HOST" "sudo cat ${ROOT_CONF}" 2>/dev/null || echo "")
    if echo "$proxy_conf" | grep -q "127.0.0.1:4433"; then
        echo "blue"
    elif echo "$proxy_conf" | grep -q "127.0.0.1:4434"; then
        echo "green"
    else
        echo "unknown"
    fi
}

# ---------- 查看状态 ----------
show_status() {
    local active; active=$(get_active)
    echo ""
    echo "═══════════════════════════════════════"
    echo "  蓝绿部署状态"
    echo "═══════════════════════════════════════"
    echo ""
    echo "  蓝色 :4433  $( [ "$active" = "blue" ] && echo '★ 活动中' || echo '○ 待命中' )"
    echo "  绿色 :4434  $( [ "$active" = "green" ] && echo '★ 活动中' || echo '○ 待命中' )"
    echo ""
    echo "  反向代理: xmclassmate.top"
    echo "  数据库:   milkydata (blue/green) / milkydata_dev (dev)"
    echo ""

    # 检查两个端口是否可达
    local blue_ok;  blue_ok=$(ssh "$SSH_HOST" "curl -s -o /dev/null -w '%{http_code}' --max-time 3 https://127.0.0.1:4433/health -k" 2>/dev/null || echo "000")
    local green_ok; green_ok=$(ssh "$SSH_HOST" "curl -s -o /dev/null -w '%{http_code}' --max-time 3 https://127.0.0.1:4434/health -k" 2>/dev/null || echo "000")
    echo "  蓝色健康: HTTP $blue_ok"
    echo "  绿色健康: HTTP $green_ok"
    echo ""
}

# ---------- 切换 ----------
switch_to() {
    local target="$1"
    local current; current=$(get_active)
    
    [ "$target" = "$current" ] && { warn "已经是 ${target} 环境，无需切换"; return 0; }

    local target_port=""
    [ "$target" = "blue" ] && target_port="4433"
    [ "$target" = "green" ] && target_port="4434"

    echo ""
    echo "═══════════════════════════════════════"
    echo "  切换: ${current} → ${target} (:${target_port})"
    echo "═══════════════════════════════════════"
    echo ""

    # 先验证目标环境健康
    echo "验证目标环境健康..."
    local proto="https"
    local extra="-k"
    local target_ok; target_ok=$(ssh "$SSH_HOST" "curl -s -o /dev/null -w '%{http_code}' --max-time 3 ${proto}://127.0.0.1:${target_port}/health ${extra}" 2>/dev/null || echo "000")
    if [ "$target_ok" != "200" ]; then
        error "目标环境 :${target_port} 健康检查失败 (HTTP $target_ok)，取消切换"
        exit 1
    fi
    info "目标环境健康 ✅"

    # 修改 proxy_pass（两个端口都是 HTTPS）
    local target_proto="https"
    info "修改 nginx proxy_pass → ${target_proto}://127.0.0.1:${target_port}..."
    ssh "$SSH_HOST" "sudo sed -i 's|proxy_pass https\?://127.0.0.1:[0-9]*|proxy_pass ${target_proto}://127.0.0.1:${target_port}|' ${ROOT_CONF}" 2>&1 || {
        error "修改 proxy_pass 失败"
        exit 1
    }

    # 重新加载 nginx
    info "重新加载 nginx..."
    ssh "$SSH_HOST" "sudo nginx -s reload" 2>&1 || {
        error "nginx 重载失败"
        exit 1
    }

    # 验证切换后
    sleep 2
    local verify; verify=$(curl -s -o /dev/null -w "%{http_code}" --max-time 5 "https://xmclassmate.top/health" 2>/dev/null || echo "000")
    if [ "$verify" = "200" ]; then
        info "切换完成 ✅ xmclassmate.top → :${target_port} (HTTP $verify)"
    else
        warn "切换完成，但 xmclassmate.top 返回 HTTP $verify（可能是旧代码无 /health 端点）"
    fi
}

# ---------- 主流程 ----------
[ $# -eq 0 ] && { show_status; exit 0; }

case "$1" in
    --status)   show_status ;;
    --switch)   [ -z "${2:-}" ] && { error "请指定 blue 或 green"; exit 1; }
                case "$2" in
                    blue|green) switch_to "$2" ;;
                    *) error "参数错误: $2 (应为 blue 或 green)" ;;
                esac ;;
    --help|-h)  usage ;;
    *) error "未知选项: $1"; usage ;;
esac