package web

import (
	"fmt"
	"log"
	"net/http"
	"strconv"

	"pcap-web-tools/internal/pcap"
)

type reorderPage struct {
	MaxUpload string
	Error     string
}

func (s *Server) handleReorderForm(w http.ResponseWriter, r *http.Request) {
	s.render(w, http.StatusOK, "reorder.html", "/reorder", reorderPage{MaxUpload: s.maxUpload()})
}

func (s *Server) handleReorder(w http.ResponseWriter, r *http.Request) {
	page := reorderPage{MaxUpload: s.maxUpload()}
	fail := func(status int, msg string) {
		page.Error = msg
		s.render(w, status, "reorder.html", "/reorder", page)
	}

	file, hdr, status, msg := s.parseUpload(w, r)
	if status != 0 {
		fail(status, msg)
		return
	}
	defer file.Close()

	// Indexing reads the whole file, so problems are reported on the page
	// before any of the download is sent.
	ro, err := pcap.NewReorder(file, hdr.Size)
	if err != nil {
		fail(http.StatusBadRequest, hdr.Filename+": "+err.Error())
		return
	}

	w.Header().Set("Content-Type", "application/vnd.tcpdump.pcap")
	w.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=%q", uploadStem(hdr)+"_reordered.pcap"))
	// Summary for scripted clients; browsers just save the file.
	w.Header().Set("X-Pcap-Packets", strconv.Itoa(ro.Packets()))
	w.Header().Set("X-Pcap-Out-Of-Order", strconv.Itoa(ro.OutOfOrder()))
	w.Header().Set("X-Pcap-Truncated", strconv.FormatBool(ro.Truncated()))
	if _, err := ro.WriteTo(w); err != nil {
		// The response has already started, so the error cannot be shown on the page.
		log.Printf("reorder %q: %v", hdr.Filename, err)
	}
}