#!/bin/bash
# 灰度回滚脚本：切回全量稳定版本，停止 canary 容器
# 用法: ./scripts/rollback_gray.sh

set -euo pipefail

NGINX_CONF="${NGINX_CONF:-/etc/nginx/sites-enabled/00-xiaoxia-saas}"
CANARY_API="${CANARY_API:-xiaoxia-api-canary}"
CANARY_WEB="${CANARY_WEB:-xiaoxia-web-canary}"

echo "============================================"
echo "  灰度回滚"
echo "  目标: 全量切回稳定版本"
echo "============================================"

# 1. 找最近的灰度备份
echo ""
echo ">>> 查找最近的灰度备份..."
LATEST_BAK=$(ls -t "${NGINX_CONF}".bak.gray.* 2>/dev/null | head -1 || true)

if [[ -z "$LATEST_BAK" ]]; then
    echo "  未找到灰度备份，尝试手动移除 upstream 配置..."
    
    # 手动回滚：移除 upstream 块，把 proxy_pass 改回 127.0.0.1
    TMP_CONF=$(mktemp)
    
    # 移除 upstream 块（从 "# Gray release upstreams" 到空行结束）
    awk '
        /^# Gray release upstreams/ { skip=1; next }
        skip && /^$/ && !found_first_empty { found_first_empty=1; next }
        skip && found_first_empty && /^$/ { skip=0; found_first_empty=0; next }
        skip { next }
        { print }
    ' "$NGINX_CONF" > "$TMP_CONF"
    
    # 把 upstream 名改回 IP
    sed -i 's|proxy_pass http://saas_api_backend|proxy_pass http://127.0.0.1:8001|g' "$TMP_CONF"
    sed -i 's|proxy_pass http://saas_web_backend/|proxy_pass http://127.0.0.1:3002/|g' "$TMP_CONF"
    
    mv "$TMP_CONF" "$NGINX_CONF"
else
    echo "  从备份恢复: $LATEST_BAK"
    cp "$LATEST_BAK" "$NGINX_CONF"
fi

# 2. 测试并 reload nginx
echo ""
echo ">>> Nginx 测试 & reload..."
if ! nginx -t 2>&1; then
    echo "  ❌ Nginx 配置测试失败！请检查"
    exit 1
fi
nginx -s reload
echo "  ✅ Nginx 已回滚，全量切回稳定版本"

# 3. 停止 canary 容器（延迟停止，保留30分钟便于排查）
echo ""
echo ">>> Canary 容器将在30分钟后停止（便于排查）"
echo "    立即停止请执行: docker rm -f $CANARY_API $CANARY_WEB"

# 30分钟后停止（后台执行，不阻塞脚本）
(
    sleep 1800
    for c in "$CANARY_API" "$CANARY_WEB"; do
        if docker ps --format '{{.Names}}' | grep -q "^${c}$"; then
            docker stop "$c" >/dev/null 2>&1 && docker rm "$c" >/dev/null 2>&1
            echo "[$(date)] 已停止 canary 容器: $c"
        fi
    done
) &

echo ""
echo "============================================"
echo "  ✅ 灰度回滚完成"
echo "  流量已全部切回稳定版本"
echo "  Canary 容器: 30分钟后自动清理"
echo "============================================"