package archive

import (
	"archive/tar"
	"compress/gzip"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"time"
)

func (this *ArchiveServer) serveDownload(w http.ResponseWriter) {
	w.Header().Set(`Content-Type`, `application/octet-stream`)
	w.Header().Set(`Content-Disposition`, `download; filename="chat-archive-`+time.Now().Format("20060102030405")+`.tar.gz"`)
	w.WriteHeader(200)

	gzw := gzip.NewWriter(w)
	defer gzw.Close()

	t := tar.NewWriter(gzw)
	defer t.Close()

	for i, ls := range this.cfg.Logs {

		slug, _ := this.bestSlugFor(&this.cfg.Logs[i])

		limit := ls.LatestDate().Next() // one off the end
		for ympair := ls.EarliestDate(); !ympair.Equals(limit); ympair = ympair.Next() {

			fname, err := this.LogFile(&ls, ympair)
			if err != nil {
				continue // no log exists for this ym
			}

			fi, err := os.Stat(fname)
			if err != nil {
				continue
			}

			fh, err := os.Open(fname)
			if err != nil {
				continue // can't open this log file
			}

			tHdr, _ := tar.FileInfoHeader(fi, "")
			tHdr.Name = fmt.Sprintf(`/%s/%d-%02d.log`, slug, ympair.Year, ympair.Month)
			t.WriteHeader(tHdr)

			func() {
				defer fh.Close()

				_, err := io.Copy(t, fh)
				if err != nil {
					log.Printf("Error while archiving file '%s': %s", fname, err.Error())
					return
				}
			}()

			t.Flush()
		}

	}

}