fix: Added LOTW badge for Lotw users colored depending on their last upload

internal/lotwusers/lotwusers.go

@@ -0,0 +1,178 @@
+// Package lotwusers tracks which callsigns are LoTW users and when they last
+// uploaded, from ARRL's public "lotw-user-activity.csv" feed. OpsLog shows a
+// colour-coded badge next to the entered callsign (recent upload = likely to
+// confirm on LoTW). The list is cached on disk so it survives restarts.
+package lotwusers
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+)
+
+// feedURL is ARRL's public LoTW last-upload activity list (CSV:
+// "CALLSIGN,YYYY-MM-DD,HH:MM:SS", one line per registered LoTW callsign).
+const feedURL = "https://lotw.arrl.org/lotw-user-activity.csv"
+
+const cacheFile = "lotw-user-activity.csv"
+
+// Info is a lookup result for one callsign.
+type Info struct {
+	IsUser     bool   `json:"is_user"`
+	LastUpload string `json:"last_upload,omitempty"` // YYYY-MM-DD
+	DaysAgo    int    `json:"days_ago"`              // days since last upload (-1 if unknown)
+}
+
+// Manager holds the parsed list + cache location.
+type Manager struct {
+	mu      sync.RWMutex
+	users   map[string]time.Time // UPPER(callsign) → last-upload date (UTC)
+	updated time.Time            // when the cache was last refreshed
+	dir     string
+	client  *http.Client
+}
+
+// NewManager loads any on-disk cache and returns a ready manager.
+func NewManager(dataDir string) *Manager {
+	m := &Manager{
+		users:  map[string]time.Time{},
+		dir:    dataDir,
+		client: &http.Client{Timeout: 90 * time.Second},
+	}
+	m.loadCache()
+	return m
+}
+
+func (m *Manager) path() string { return filepath.Join(m.dir, cacheFile) }
+
+func (m *Manager) loadCache() {
+	data, err := os.ReadFile(m.path())
+	if err != nil {
+		return
+	}
+	m.parse(data)
+	if fi, e := os.Stat(m.path()); e == nil {
+		m.mu.Lock()
+		m.updated = fi.ModTime()
+		m.mu.Unlock()
+	}
+}
+
+// Download fetches the latest list, caches it to disk and replaces the in-memory
+// map. Returns the number of callsigns loaded.
+func (m *Manager) Download(ctx context.Context) (int, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, feedURL, nil)
+	if err != nil {
+		return 0, err
+	}
+	req.Header.Set("User-Agent", "OpsLog")
+	resp, err := m.client.Do(req)
+	if err != nil {
+		return 0, fmt.Errorf("lotwusers: request failed: %w", err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return 0, fmt.Errorf("lotwusers: http %d", resp.StatusCode)
+	}
+	body, err := io.ReadAll(io.LimitReader(resp.Body, 64*1024*1024))
+	if err != nil {
+		return 0, fmt.Errorf("lotwusers: read: %w", err)
+	}
+	n := m.parse(body)
+	if n == 0 {
+		return 0, fmt.Errorf("lotwusers: feed parsed to 0 callsigns")
+	}
+	_ = os.WriteFile(m.path(), body, 0o644) // best-effort cache
+	m.mu.Lock()
+	m.updated = time.Now()
+	m.mu.Unlock()
+	return n, nil
+}
+
+// parse loads the CSV bytes into the map and returns the count.
+func (m *Manager) parse(data []byte) int {
+	users := make(map[string]time.Time, 1<<20)
+	sc := bufio.NewScanner(bytes.NewReader(data))
+	sc.Buffer(make([]byte, 1024*1024), 1024*1024)
+	for sc.Scan() {
+		line := strings.TrimSpace(sc.Text())
+		if line == "" {
+			continue
+		}
+		parts := strings.Split(line, ",")
+		if len(parts) < 2 {
+			continue
+		}
+		call := strings.ToUpper(strings.TrimSpace(parts[0]))
+		if call == "" || strings.EqualFold(call, "callsign") {
+			continue // header row
+		}
+		t, err := time.Parse("2006-01-02", strings.TrimSpace(parts[1]))
+		if err != nil {
+			continue
+		}
+		users[call] = t
+	}
+	if len(users) == 0 {
+		return 0
+	}
+	m.mu.Lock()
+	m.users = users
+	m.mu.Unlock()
+	return len(users)
+}
+
+// Lookup reports whether callsign is a LoTW user and how long ago it uploaded.
+// Tries the exact call, then (for portable calls like "EA8/DL1ABC" or "F5ABC/P")
+// the longest slash-separated segment — the base call LoTW is keyed on.
+func (m *Manager) Lookup(callsign string) Info {
+	c := strings.ToUpper(strings.TrimSpace(callsign))
+	if c == "" {
+		return Info{DaysAgo: -1}
+	}
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	if len(m.users) == 0 {
+		return Info{DaysAgo: -1}
+	}
+	t, ok := m.users[c]
+	if !ok && strings.Contains(c, "/") {
+		base := ""
+		for _, seg := range strings.Split(c, "/") {
+			if len(seg) > len(base) {
+				base = seg
+			}
+		}
+		t, ok = m.users[base]
+	}
+	if !ok {
+		return Info{DaysAgo: -1}
+	}
+	days := int(time.Since(t).Hours() / 24)
+	if days < 0 {
+		days = 0
+	}
+	return Info{IsUser: true, LastUpload: t.Format("2006-01-02"), DaysAgo: days}
+}
+
+// Count returns how many callsigns are loaded.
+func (m *Manager) Count() int {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	return len(m.users)
+}
+
+// Updated returns when the list was last refreshed (zero if never).
+func (m *Manager) Updated() time.Time {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	return m.updated
+}