package server

import (
	"encoding/base64"
	"encoding/json"
	"io"
	"net/http"
	"path"
	"time"

	"github.com/x-grk/longpolling-remote-access/internal/proto"
)

// fsOps maps the URL op segment to a proto task type.
var fsOps = map[string]string{
	"list":    proto.TaskFSList,
	"read":    proto.TaskFSRead,
	"write":   proto.TaskFSWrite,
	"mkdir":   proto.TaskFSMkdir,
	"delete":  proto.TaskFSDelete,
	"deltree": proto.TaskFSDelTree,
	"unzip":   proto.TaskFSUnzip,
	"zip":     proto.TaskFSZip,
	"move":    proto.TaskFSMove,
}

// fsTaskTimeout bounds how long we wait for an agent to answer a file op.
const fsTaskTimeout = 60 * time.Second

func (s *Server) handleFilesPage(w http.ResponseWriter, r *http.Request) {
	id := r.PathValue("id")
	a, err := s.db.GetAgent(id)
	if err != nil || a == nil {
		http.NotFound(w, r)
		return
	}
	s.render(w, "files.html", map[string]any{"Agent": a, "EditLimit": proto.FSReadCap})
}

// POST /api/panel/agents/{id}/fs/{op} - run a file-manager operation on the
// agent and return its result. The request body is the op's JSON args and is
// forwarded verbatim to the agent.
func (s *Server) handleFSOp(w http.ResponseWriter, r *http.Request) {
	agentID := r.PathValue("id")
	op := r.PathValue("op")
	taskType, ok := fsOps[op]
	if !ok {
		http.Error(w, "unknown op", http.StatusBadRequest)
		return
	}
	a, err := s.db.GetAgent(agentID)
	if err != nil || a == nil {
		http.NotFound(w, r)
		return
	}
	if !s.online(a) {
		writeJSON(w, proto.TaskResult{Error: "машина офлайн"})
		return
	}
	args, err := io.ReadAll(http.MaxBytesReader(w, r.Body, 64<<20))
	if err != nil {
		http.Error(w, "bad request", http.StatusBadRequest)
		return
	}

	taskID, resultCh := s.hub.CreateTask(agentID, taskType, args)
	defer s.hub.DiscardTask(taskID)

	select {
	case res := <-resultCh:
		writeJSON(w, res)
	case <-time.After(fsTaskTimeout):
		writeJSON(w, proto.TaskResult{Error: "таймаут ожидания агента"})
	}
}

// GET /api/panel/agents/{id}/fs/download?path=... - stream a file as a download.
func (s *Server) handleFSDownload(w http.ResponseWriter, r *http.Request) {
	agentID := r.PathValue("id")
	p := r.URL.Query().Get("path")
	a, err := s.db.GetAgent(agentID)
	if err != nil || a == nil {
		http.NotFound(w, r)
		return
	}
	if !s.online(a) {
		http.Error(w, "машина офлайн", http.StatusServiceUnavailable)
		return
	}
	args, _ := json.Marshal(proto.FSPathArgs{Path: p})
	taskID, ch := s.hub.CreateTask(agentID, proto.TaskFSDownload, args)
	defer s.hub.DiscardTask(taskID)

	select {
	case res := <-ch:
		if !res.OK {
			http.Error(w, res.Error, http.StatusBadGateway)
			return
		}
		var rr proto.FSReadResult
		if err := json.Unmarshal(res.Data, &rr); err != nil {
			http.Error(w, "bad result", http.StatusBadGateway)
			return
		}
		data, _ := base64.StdEncoding.DecodeString(rr.Content)
		name := path.Base(p)
		w.Header().Set("Content-Type", "application/octet-stream")
		w.Header().Set("Content-Disposition", "attachment; filename=\""+name+"\"")
		if rr.Truncated {
			w.Header().Set("X-Truncated", "1")
		}
		_, _ = w.Write(data)
	case <-time.After(fsTaskTimeout):
		http.Error(w, "таймаут ожидания агента", http.StatusGatewayTimeout)
	}
}