feat(hamqth): upload the whole log in one file

The per-QSO API is the only correct way to send a SELECTION, and at the
pace it must be driven a 14k backlog costs the better part of an hour.
HamQTH's other endpoint takes a whole log as one file — and REPLACES
what is on the site with it: its documentation says plainly that partial
uploads do not exist. So it is offered as its own deliberate act behind
a confirmation, never as the batch path behind 'send these', where it
would delete every QSO the operator had not selected.

Scoped to the callsign this profile uploads as, so a database holding
two operators' contacts cannot push one into the other's log; tar.gz
above 12 MB because the ceiling is 20 and a six-figure log passes it as
text; and every QSO not already stamped is marked sent afterwards, in
bulk, so the backlog list agrees with reality.

internal/extsvc/hamqth.go

@@ -1,9 +1,13 @@
 package extsvc
 
 import (
+	"archive/tar"
+	"bytes"
+	"compress/gzip"
 	"context"
 	"fmt"
 	"io"
+	"mime/multipart"
 	"net/http"
 	"net/url"
 	"strings"
@@ -18,6 +22,20 @@ import (
 // duplicate…, reason in the body), 403 wrong credentials, 500 server error.
 const hamqthUploadURL = "https://www.hamqth.com/qso_realtime.php"
 
+// hamqthFullLogURL takes a WHOLE log as a file. Note "whole": HamQTH's own
+// documentation says "you always have to upload whole log. HamQTH doesn't
+// support partial upload" — the file REPLACES what is on the site. That is why
+// it is not the batch path for a selection, and why the caller must have said
+// so out loud before we get here.
+const hamqthFullLogURL = "https://www.hamqth.com/prg_log_upload.php"
+
+// hamqthMaxUpload is the documented ceiling for one upload.
+const hamqthMaxUpload = 20 << 20
+
+// hamqthCompressAbove is where a plain .adi stops being sent as text. Well
+// under the limit: the multipart envelope and the form fields ride along too.
+const hamqthCompressAbove = 12 << 20
+
 // hamqthLoginURL is the callbook session login — the one authenticated HamQTH
 // endpoint that cannot change anything in the log, which is what the settings
 // Test button must call.
@@ -92,6 +110,127 @@ func uploadHamQTHTo(ctx context.Context, client *http.Client, endpoint string, c
 	}
 }
 
+// UploadHamQTHFullLog replaces the account's log with the given ADIF.
+//
+// DESTRUCTIVE by design of the remote API, not by ours: everything on HamQTH
+// for this callsign that is not in this file stops existing. The caller owns
+// the confirmation.
+//
+// The file goes in the multipart field "f" (HamQTH's own curl example:
+// curl -F [email protected] -F send_log=OK -F u=… -F p=…). A large log is sent as a
+// tar.gz — one of the archive formats the site unpacks — because the ceiling is
+// 20 MB and a six-figure log passes it as plain text.
+func UploadHamQTHFullLog(ctx context.Context, client *http.Client, cfg ServiceConfig, adifText string) (UploadResult, error) {
+	user := strings.TrimSpace(cfg.Username)
+	switch {
+	case user == "":
+		return UploadResult{}, fmt.Errorf("hamqth: username not set")
+	case cfg.Password == "":
+		return UploadResult{}, fmt.Errorf("hamqth: password not set")
+	case strings.TrimSpace(adifText) == "":
+		return UploadResult{}, fmt.Errorf("hamqth: nothing to upload")
+	}
+
+	payload := []byte(adifText)
+	name := "opslog.adi"
+	if len(payload) > hamqthCompressAbove {
+		gz, err := tarGzADIF(payload)
+		if err != nil {
+			return UploadResult{}, fmt.Errorf("hamqth: compressing the log: %w", err)
+		}
+		payload, name = gz, "opslog.tar.gz"
+	}
+	if len(payload) > hamqthMaxUpload {
+		return UploadResult{}, fmt.Errorf("hamqth: the log is %d MB compressed, over HamQTH's %d MB limit",
+			len(payload)>>20, hamqthMaxUpload>>20)
+	}
+
+	var body bytes.Buffer
+	mw := multipart.NewWriter(&body)
+	_ = mw.WriteField("u", user)
+	_ = mw.WriteField("p", cfg.Password)
+	if c := strings.ToUpper(strings.TrimSpace(cfg.Callsign)); c != "" {
+		_ = mw.WriteField("c", c)
+	}
+	_ = mw.WriteField("send_log", "OK")
+	fw, err := mw.CreateFormFile("f", name)
+	if err != nil {
+		return UploadResult{}, err
+	}
+	if _, err := fw.Write(payload); err != nil {
+		return UploadResult{}, err
+	}
+	if err := mw.Close(); err != nil {
+		return UploadResult{}, err
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, hamqthFullLogURL, &body)
+	if err != nil {
+		return UploadResult{}, err
+	}
+	req.Header.Set("Content-Type", mw.FormDataContentType())
+	if client == nil {
+		// A whole log is a long POST on a slow uplink.
+		client = &http.Client{Timeout: 10 * time.Minute}
+	}
+	resp, err := client.Do(req)
+	if err != nil {
+		return UploadResult{}, err
+	}
+	defer resp.Body.Close()
+	raw, _ := io.ReadAll(io.LimitReader(resp.Body, 64<<10))
+	msg := strings.TrimSpace(string(raw))
+	if looksLikeHTML(msg) {
+		msg = ""
+	}
+	if resp.StatusCode != http.StatusOK {
+		if msg != "" && len(msg) < 300 {
+			return UploadResult{}, fmt.Errorf("hamqth: HTTP %d: %s", resp.StatusCode, msg)
+		}
+		return UploadResult{}, fmt.Errorf("hamqth: HTTP %d", resp.StatusCode)
+	}
+	// The site answers in prose, and only its own refusals are worth reading
+	// back: the ADIF itself is validated later, in the background, and any
+	// complaint about it reaches the operator by e-mail rather than here.
+	low := strings.ToLower(msg)
+	switch {
+	case strings.Contains(low, "successfully"):
+		return UploadResult{OK: true, Message: msg}, nil
+	case strings.Contains(low, "wrong username"), strings.Contains(low, "password"):
+		return UploadResult{}, fmt.Errorf("hamqth: %s", msg)
+	case strings.Contains(low, "cannot upload log for this callsign"):
+		return UploadResult{}, fmt.Errorf("hamqth: %s", msg)
+	case msg == "":
+		// HTTP 200 with nothing to say: taken as accepted, and said so.
+		return UploadResult{OK: true, Message: "uploaded (no reply text)"}, nil
+	default:
+		return UploadResult{OK: false, Message: msg}, nil
+	}
+}
+
+// tarGzADIF wraps the ADIF as log.adi inside a tar.gz — the archive must carry
+// a .adi/.adif member for HamQTH to find the log in it.
+func tarGzADIF(adif []byte) ([]byte, error) {
+	var out bytes.Buffer
+	gz := gzip.NewWriter(&out)
+	tw := tar.NewWriter(gz)
+	if err := tw.WriteHeader(&tar.Header{
+		Name: "opslog.adi", Mode: 0o644, Size: int64(len(adif)),
+	}); err != nil {
+		return nil, err
+	}
+	if _, err := tw.Write(adif); err != nil {
+		return nil, err
+	}
+	if err := tw.Close(); err != nil {
+		return nil, err
+	}
+	if err := gz.Close(); err != nil {
+		return nil, err
+	}
+	return out.Bytes(), nil
+}
+
 // TestHamQTH verifies the credentials against the callbook session login —
 // authenticated, and unable to touch the log.
 func TestHamQTH(ctx context.Context, client *http.Client, cfg ServiceConfig) (string, error) {