// udeServer: DeleteService 走事务 —— 同一事务内先删该服务下的 t_directory,
// 再删 t_service。任一步失败全部回滚,不会残留孤儿目录数据。

package logic

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"path"
	"strings"

	"udeServer/internal/model"
	"udeServer/internal/svc"
	"udeServer/internal/types"

	"github.com/zeromicro/go-zero/core/logx"
	"github.com/zeromicro/go-zero/core/stores/sqlx"
)

type DeleteServiceLogic struct {
	logx.Logger
	ctx    context.Context
	svcCtx *svc.ServiceContext
}

func NewDeleteServiceLogic(ctx context.Context, svcCtx *svc.ServiceContext) *DeleteServiceLogic {
	return &DeleteServiceLogic{
		Logger: logx.WithContext(ctx),
		ctx:    ctx,
		svcCtx: svcCtx,
	}
}

func (l *DeleteServiceLogic) DeleteService(req *types.ServiceIdReq) (*types.DeleteResp, error) {
	if err := checkId(req.Id); err != nil {
		return nil, err
	}
	// 先查出服务实体:删库前要拿 ip/port 去通知外挂程序卸载,删了就查不到了
	svc, err := findService(l.ctx, l.svcCtx.ServiceModel, req.Id)
	if err != nil {
		return nil, err
	}

	// P1 联动卸载:先卸载后删库。卸载失败软处理(不阻塞删除,外挂机器可能已下线),
	// 聚合成 unmountWarning 由前端弹黄色警告。
	unmountWarning := l.notifyFuseUnmount(svc)

	err = l.svcCtx.DB.Transact(func(session sqlx.Session) error {
		dirModel := l.svcCtx.DirectoryModel.WithSession(session)
		svcModel := l.svcCtx.ServiceModel.WithSession(session)

		if err := dirModel.DeleteByServiceId(l.ctx, req.Id); err != nil {
			return fmt.Errorf("delete t_directory of service %d: %w", req.Id, err)
		}
		if err := svcModel.Delete(l.ctx, req.Id); err != nil {
			return fmt.Errorf("delete t_service %d: %w", req.Id, err)
		}
		return nil
	})
	if err != nil {
		l.Errorf("delete service tx failed: %v", err)
		return nil, err
	}

	resp := &types.DeleteResp{Ok: true}
	if unmountWarning != "" {
		resp.UnmountWarning = unmountWarning
	}
	return resp, nil
}

// notifyFuseUnmount 删库前回调外挂程序(svc.Ip:svc.Port)的 GET /api/fuseUnMount 接口,
// 逐目录卸载该服务全部 FUSE 挂载。
// 软处理:单个目录失败只记录并聚合,绝不阻塞删除流程(外挂机器可能已关机,
// 服务记录必须还能删)。返回空串 = 全部卸载成功或无需卸载。
func (l *DeleteServiceLogic) notifyFuseUnmount(svc *model.TService) string {
	ip, port := svc.Ip.String, svc.Port // port 已是 int64
	if ip == "" || port == 0 {
		return "外挂服务 IP/端口为空,无法联动卸载,目录可能仍处于挂载状态"
	}
	dirs, err := l.svcCtx.DirectoryModel.FindDirsByServiceId(l.ctx, svc.Id)
	if err != nil {
		return fmt.Sprintf("查询保护目录失败,无法联动卸载: %v", err)
	}
	if len(dirs) == 0 {
		return "" // 没配保护目录,无需卸载
	}
	baseURL := fmt.Sprintf("http://%s:%d/api/fuseUnMount", ip, port) // %d:port 是 int64
	var msgs []string
	for _, mount := range dirs {
		// path.Clean(非 filepath!):该路径发给远程 Linux 外挂程序,必须保持 / 分隔符
		cleanMount := path.Clean(mount)
		reqURL, uerr := url.Parse(baseURL)
		if uerr != nil {
			msgs = append(msgs, fmt.Sprintf("解析 URL 失败: %v", uerr))
			continue
		}
		// q.Encode() 自动做 URL 编码(/ → %2F),外挂侧 Query().Get 自动解码还原
		q := reqURL.Query()
		q.Set("mount", cleanMount)
		reqURL.RawQuery = q.Encode()
		l.Infof("fuse unmount forward: GET %s", reqURL.String()) // 打出转发 URL 便于排查
		resp, rerr := fuseMountClient.Get(reqURL.String())       // 复用挂载逻辑里的 HTTP 客户端(同包变量)
		if rerr != nil {
			msgs = append(msgs, fmt.Sprintf("卸载目录 %s 失败(外挂程序未启动?): %v", cleanMount, rerr))
			continue
		}
		if resp.StatusCode >= http.StatusBadRequest {
			snippet, _ := io.ReadAll(io.LimitReader(resp.Body, 256)) // 带出外挂错误内容(前 256 字节)
			resp.Body.Close()
			msgs = append(msgs, fmt.Sprintf("卸载目录 %s 失败,外挂程序返回 HTTP %d: %s", cleanMount, resp.StatusCode, string(snippet)))
			continue
		}
		_, _ = io.Copy(io.Discard, resp.Body) // 读入"黑洞"保证 TCP 连接复用 Keep-Alive
		resp.Body.Close()
		l.Infof("fuse unmount ok: %s", cleanMount)
	}
	if len(msgs) == 0 {
		return ""
	}
	return "服务已删除,但卸载挂载失败: " + strings.Join(msgs, "; ")
}