package server

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"log/slog"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"time"

	"github.com/coder/websocket"

	"g.fc.run/misc/byre/internal/clients"
)

func (s *Server) ConnectClient(w http.ResponseWriter, r *http.Request) {
	host := r.Header.Get("Byre-Host")
	if host == "" {
		writeError(w, http.StatusBadRequest, errors.New("missing Byre-Host"))
		return
	}

	ws, err := websocket.Accept(w, r, nil)
	if err != nil {
		slog.Warn("accept client websocket", "host", host, "err", err)
		return
	}
	defer ws.CloseNow()

	s.clients.Serve(r.Context(), ws, clients.Client{
		Login:       actor(r),
		Host:        host,
		Commit:      r.Header.Get("Byre-Commit"),
		ConnectedAt: time.Now().UTC(),
	})
}

func (s *Server) GetClientTransfer(w http.ResponseWriter, r *http.Request, transferID string) {
	t, ok := s.clients.Transfer(transferID)
	if !ok || t.Receive {
		writeError(w, http.StatusNotFound, fmt.Errorf("no transfer %s to send", transferID))
		return
	}

	w.Header().Set("Content-Type", "application/gzip")
	cmd := exec.CommandContext(r.Context(), "tar", "-czf", "-", "-C", t.Dir, "--", t.Name)
	cmd.Stdout = w
	stderr := &bytes.Buffer{}
	cmd.Stderr = stderr
	err := cmd.Run()
	if err != nil {
		slog.Error("stream client transfer", "transfer", transferID, "dir", t.Dir, "name", t.Name, "err", err, "stderr", stderr.String())
		panic(http.ErrAbortHandler)
	}
}

func (s *Server) PutClientTransfer(w http.ResponseWriter, r *http.Request, transferID string) {
	t, ok := s.clients.Transfer(transferID)
	if !ok || !t.Receive {
		writeError(w, http.StatusNotFound, fmt.Errorf("no transfer %s to receive", transferID))
		return
	}

	f, err := os.OpenFile(filepath.Join(t.Dir, t.Name), os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0o600)
	if err != nil {
		writeError(w, http.StatusNotFound, fmt.Errorf("transfer %s: %w", transferID, err))
		return
	}
	_, err = io.Copy(f, r.Body)
	cerr := f.Close()
	if err == nil {
		err = cerr
	}
	if err != nil {
		writeError(w, http.StatusInternalServerError, fmt.Errorf("receive transfer %s: %w", transferID, err))
		return
	}
	w.WriteHeader(http.StatusNoContent)
}