2026-07-26 18:54:43 +07:00
2 changed files with 440 additions and 0 deletions
@@ -0,0 +1,162 @@
+package main
+
+import (
+	"context"
+	"log"
+	"time"
+)
+
+// fetcher retrieves a series page. It exists as an interface so tests can inject
+// a fake: nothing in the test suite may touch the network or the TLS client.
+type fetcher interface {
+	Get(ctx context.Context, url string) (body string, status int, err error)
+}
+
+// latestPoller re-checks each bookmarked series' newest published chapter on a
+// schedule, independent of the userscript's own in-browser checks. The two run
+// in parallel and report the same observable fact, so whichever writes last wins
+// and neither needs to know about the other.
+//
+// Two clocks, deliberately independent:
+//
+//   - interval is how often this goroutine wakes up and looks.
+//   - cooldown is how long one bookmark rests since its own last check.
+//
+// Only the cooldown is per bookmark, and it is enforced by the WHERE clause in
+// DueForLatestCheck rather than by any timer. Shortening interval therefore
+// cannot shorten anyone's cooldown; it only makes the poller wake up and find
+// nothing due more often.
+type latestPoller struct {
+	store    *Store
+	fetch    fetcher
+	now      func() time.Time // injected so tests can freeze it
+	cooldown time.Duration
+	interval time.Duration
+	stagger  time.Duration
+	batch    int
+}
+
+// Run polls until ctx is cancelled.
+//
+// runOnce is called synchronously, so a batch that overruns the tick delays the
+// next one instead of stacking a second batch on top of it. That is the intended
+// failure mode for a misconfigured batch x stagger: a slower cadence, never
+// concurrent fetch storms.
+func (p *latestPoller) Run(ctx context.Context) {
+	log.Printf("latest-chapter poller: interval=%s cooldown=%s batch=%d stagger=%s",
+		p.interval, p.cooldown, p.batch, p.stagger)
+	t := time.NewTicker(p.interval)
+	defer t.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			log.Println("latest-chapter poller: stopped")
+			return
+		case <-t.C:
+			p.runOnce(ctx)
+		}
+	}
+}
+
+// runOnce processes one batch of due bookmarks.
+func (p *latestPoller) runOnce(ctx context.Context) {
+	cutoff := p.now().Add(-p.cooldown).UnixMilli()
+	due, err := p.store.DueForLatestCheck(cutoff, p.batch)
+	if err != nil {
+		log.Printf("latest poll: due query: %v", err)
+		return
+	}
+	if len(due) == 0 {
+		return
+	}
+
+	checked := 0
+	for i, b := range due {
+		if ctx.Err() != nil {
+			break
+		}
+		// Staggered rather than fired together: a burst of simultaneous requests
+		// from one server IP is the traffic shape most likely to move that IP's
+		// bot score. This is the server-side analogue of the userscript's "one
+		// series per navigation ... indistinguishable from browsing" (L455-456).
+		if i > 0 && p.stagger > 0 {
+			select {
+			case <-ctx.Done():
+				return
+			case <-time.After(p.stagger):
+			}
+		}
+		p.checkOne(ctx, b)
+		checked++
+	}
+	// due vs checked is how you tell which constraint is binding: ticks that
+	// report due=0 mean the cooldown is the limit, ticks that report due==batch
+	// every time mean throughput is.
+	log.Printf("latest poll: due=%d checked=%d", len(due), checked)
+}
+
+// checkOne re-checks one series. Every failure path here is "log and move on":
+// the poller is a best-effort enhancement, and no single bad series may stall a
+// batch or take down the process.
+func (p *latestPoller) checkOne(ctx context.Context, b Bookmark) {
+	defer func() {
+		if r := recover(); r != nil {
+			log.Printf("latest poll %q: recovered from panic: %v", b.Key, r)
+		}
+	}()
+
+	// Stamped before the fetch, not after, so an error, a timeout, or a shutdown
+	// mid-request still consumes the cooldown. Otherwise a renamed or deleted
+	// series would be retried on every single tick forever. The userscript
+	// stamps in the same order and for the same reason (L471-473).
+	if err := p.store.MarkLatestChecked(b.Key, p.now().UnixMilli()); err != nil {
+		log.Printf("latest poll %q: mark checked: %v", b.Key, err)
+		return
+	}
+
+	body, status, err := p.fetch.Get(ctx, b.SeriesURL)
+	if err != nil {
+		log.Printf("latest poll %q: fetch %s: %v", b.Key, b.SeriesURL, err)
+		return
+	}
+	if status != 200 {
+		log.Printf("latest poll %q: fetch %s: status %d", b.Key, b.SeriesURL, status)
+		return
+	}
+
+	latest, ok := latestChapterFrom(b.Site, b.SeriesURL, body)
+	if !ok {
+		// Most likely a challenge page or a layout change. Either way the row is
+		// already stamped, so this waits out a cooldown instead of hot-looping.
+		log.Printf("latest poll %q: no chapter links in %d bytes", b.Key, len(body))
+		return
+	}
+
+	// Re-read: the row may have been updated or deleted while the fetch was in
+	// flight, and writing b back wholesale would undo that.
+	cur, found, err := p.store.Get(b.Key)
+	if err != nil {
+		log.Printf("latest poll %q: reread: %v", b.Key, err)
+		return
+	}
+	if !found {
+		return
+	}
+	// Equality, not >, mirroring the userscript (L427): a site that retracts a
+	// chapter should correct the stored number downward.
+	if cur.LatestChapterNum != nil && *cur.LatestChapterNum == latest.Num {
+		return
+	}
+
+	num := latest.Num
+	cur.LatestChapter = latest.Label
+	cur.LatestChapterNum = &num
+	// A candidate only. last_chapter_num is untouched, so the CASE in Upsert
+	// keeps the stored updated_at and the bookmark list does not reorder.
+	cur.UpdatedAt = p.now().UnixMilli()
+	if _, err := p.store.Upsert(cur); err != nil {
+		log.Printf("latest poll %q: upsert: %v", b.Key, err)
+		return
+	}
+	log.Printf("latest poll %q: latest is now %s", b.Key, latest.Label)
+}
@@ -0,0 +1,278 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"sync"
+	"testing"
+	"time"
+)
+
+// fakeFetcher stands in for the network. Every poller test uses it, so nothing
+// in this file can reach tls-client or a real site.
+type fakeFetcher struct {
+	mu     sync.Mutex
+	calls  []string
+	body   string
+	status int
+	err    error
+	// perURL overrides body/status/err for specific URLs.
+	perURL map[string]fakeResponse
+}
+
+type fakeResponse struct {
+	body   string
+	status int
+	err    error
+}
+
+func (f *fakeFetcher) Get(ctx context.Context, url string) (string, int, error) {
+	f.mu.Lock()
+	f.calls = append(f.calls, url)
+	f.mu.Unlock()
+	if r, ok := f.perURL[url]; ok {
+		return r.body, r.status, r.err
+	}
+	return f.body, f.status, f.err
+}
+
+func (f *fakeFetcher) callCount() int {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	return len(f.calls)
+}
+
+// newTestPoller wires a poller with a frozen clock and no stagger, so tests run
+// instantly and deterministically.
+func newTestPoller(t *testing.T, s *Store, f fetcher, at time.Time) *latestPoller {
+	t.Helper()
+	return &latestPoller{
+		store:    s,
+		fetch:    f,
+		now:      func() time.Time { return at },
+		cooldown: time.Hour,
+		interval: 10 * time.Minute,
+		stagger:  0,
+		batch:    14,
+	}
+}
+
+func TestRunOnceRecordsLatestChapter(t *testing.T) {
+	s := newTestStore(t)
+	const url = "https://asurascans.com/comics/chronicles-of-the-demon-faction-f886a8af"
+	seedForCheck(t, s, "asura:chronicles-of-the-demon-faction-f886a8af", url, 0)
+
+	now := time.UnixMilli(5_000_000)
+	f := &fakeFetcher{body: asuraSeriesFixture, status: 200}
+	newTestPoller(t, s, f, now).runOnce(context.Background())
+
+	b, ok, err := s.Get("asura:chronicles-of-the-demon-faction-f886a8af")
+	if err != nil || !ok {
+		t.Fatalf("Get: %v ok=%v", err, ok)
+	}
+	if b.LatestChapterNum == nil || *b.LatestChapterNum != 181 {
+		t.Fatalf("LatestChapterNum = %v, want 181", b.LatestChapterNum)
+	}
+	if b.LatestChapter != "Chapter 181" {
+		t.Fatalf("LatestChapter = %q, want %q", b.LatestChapter, "Chapter 181")
+	}
+	if got := readLatestCheckedAt(t, s, "asura:chronicles-of-the-demon-faction-f886a8af"); got != now.UnixMilli() {
+		t.Fatalf("latest_checked_at = %d, want %d", got, now.UnixMilli())
+	}
+}
+
+// The whole point of the updated_at CASE in Upsert: a newly published chapter is
+// not reading progress and must not move the series up the list.
+func TestRunOnceDoesNotReorderList(t *testing.T) {
+	s := newTestStore(t)
+	const url = "https://asurascans.com/comics/chronicles-of-the-demon-faction-f886a8af"
+	const key = "asura:chronicles-of-the-demon-faction-f886a8af"
+
+	// "other" is the most recently read, so it must stay at the top of List().
+	if _, err := s.Upsert(Bookmark{
+		Key: "asura:other", Site: "asura", SeriesID: "other",
+		SeriesURL: "https://asurascans.com/comics/other", UpdatedAt: 9_000_000,
+	}); err != nil {
+		t.Fatalf("seed other: %v", err)
+	}
+	seedForCheck(t, s, key, url, 0)
+	before, _, err := s.Get(key)
+	if err != nil {
+		t.Fatalf("Get before: %v", err)
+	}
+
+	f := &fakeFetcher{body: asuraSeriesFixture, status: 200}
+	newTestPoller(t, s, f, time.UnixMilli(9_999_999)).runOnce(context.Background())
+
+	after, _, err := s.Get(key)
+	if err != nil {
+		t.Fatalf("Get after: %v", err)
+	}
+	if after.UpdatedAt != before.UpdatedAt {
+		t.Fatalf("updated_at moved from %d to %d on a latest-chapter bump",
+			before.UpdatedAt, after.UpdatedAt)
+	}
+	list, err := s.List()
+	if err != nil {
+		t.Fatalf("List: %v", err)
+	}
+	if list[0].Key != "asura:other" {
+		t.Fatalf("list reordered: head is %q, want asura:other", list[0].Key)
+	}
+}
+
+// A failed fetch must still consume the cooldown, or a renamed series gets
+// retried on every tick forever.
+func TestRunOnceMarksCheckedOnFailure(t *testing.T) {
+	tests := []struct {
+		name string
+		resp fakeResponse
+	}{
+		{"network error", fakeResponse{err: errors.New("dial tcp: refused")}},
+		{"non-200", fakeResponse{body: "nope", status: 503}},
+		{"challenge page", fakeResponse{body: challengeFixture, status: 200}},
+		{"empty body", fakeResponse{body: "", status: 200}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			s := newTestStore(t)
+			const url = "https://asurascans.com/comics/x"
+			seedForCheck(t, s, "asura:x", url, 0)
+
+			now := time.UnixMilli(7_000_000)
+			f := &fakeFetcher{perURL: map[string]fakeResponse{url: tt.resp}}
+			newTestPoller(t, s, f, now).runOnce(context.Background())
+
+			if got := readLatestCheckedAt(t, s, "asura:x"); got != now.UnixMilli() {
+				t.Fatalf("latest_checked_at = %d, want %d", got, now.UnixMilli())
+			}
+			b, _, err := s.Get("asura:x")
+			if err != nil {
+				t.Fatalf("Get: %v", err)
+			}
+			if b.LatestChapterNum != nil {
+				t.Fatalf("LatestChapterNum = %v, want nil on a failed check", *b.LatestChapterNum)
+			}
+		})
+	}
+}
+
+func TestRunOnceRespectsBatchLimit(t *testing.T) {
+	s := newTestStore(t)
+	for i := 0; i < 20; i++ {
+		key := "asura:s" + string(rune('a'+i))
+		seedForCheck(t, s, key, "https://asurascans.com/comics/"+key, 0)
+	}
+
+	f := &fakeFetcher{body: "", status: 200}
+	p := newTestPoller(t, s, f, time.UnixMilli(5_000_000))
+	p.batch = 5
+	p.runOnce(context.Background())
+
+	if got := f.callCount(); got != 5 {
+		t.Fatalf("fetched %d series, want 5 (batch limit)", got)
+	}
+}
+
+// One unreachable series must not abandon the rest of the batch.
+func TestRunOnceOneBadSeriesDoesNotStallBatch(t *testing.T) {
+	s := newTestStore(t)
+	keys := []string{"asura:a", "asura:b", "asura:c", "asura:d", "asura:e"}
+	for _, k := range keys {
+		seedForCheck(t, s, k, "https://asurascans.com/comics/"+k, 0)
+	}
+
+	now := time.UnixMilli(6_000_000)
+	f := &fakeFetcher{
+		body: "", status: 200,
+		perURL: map[string]fakeResponse{
+			"https://asurascans.com/comics/asura:b": {err: errors.New("boom")},
+		},
+	}
+	newTestPoller(t, s, f, now).runOnce(context.Background())
+
+	if got := f.callCount(); got != 5 {
+		t.Fatalf("fetched %d series, want all 5 attempted", got)
+	}
+	for _, k := range keys {
+		if got := readLatestCheckedAt(t, s, k); got != now.UnixMilli() {
+			t.Fatalf("%s latest_checked_at = %d, want %d", k, got, now.UnixMilli())
+		}
+	}
+}
+
+// The cooldown is enforced by the due query, so a second immediate pass must do
+// nothing at all — this is what makes the tick interval independent of it.
+func TestRunOnceHonoursCooldownAcrossPasses(t *testing.T) {
+	s := newTestStore(t)
+	const url = "https://asurascans.com/comics/x"
+	seedForCheck(t, s, "asura:x", url, 0)
+
+	now := time.UnixMilli(8_000_000)
+	f := &fakeFetcher{body: asuraSeriesFixture, status: 200}
+	p := newTestPoller(t, s, f, now)
+
+	p.runOnce(context.Background())
+	if got := f.callCount(); got != 1 {
+		t.Fatalf("first pass fetched %d, want 1", got)
+	}
+	// Same instant, and again 59 minutes later: both inside the 1h cooldown.
+	p.runOnce(context.Background())
+	p.now = func() time.Time { return now.Add(59 * time.Minute) }
+	p.runOnce(context.Background())
+	if got := f.callCount(); got != 1 {
+		t.Fatalf("fetched %d times inside the cooldown, want 1", got)
+	}
+	// Past the cooldown, it is due again.
+	p.now = func() time.Time { return now.Add(61 * time.Minute) }
+	p.runOnce(context.Background())
+	if got := f.callCount(); got != 2 {
+		t.Fatalf("fetched %d times after the cooldown, want 2", got)
+	}
+}
+
+// A site that retracts a chapter should correct the stored number downward,
+// mirroring the userscript's equality check (L427) rather than a >.
+func TestRunOnceCorrectsDownward(t *testing.T) {
+	s := newTestStore(t)
+	const url = "https://demonicscans.org/manga/Catastrophic-Necromancer"
+	const key = "demonic:Catastrophic-Necromancer"
+
+	high := 400.0
+	if _, err := s.Upsert(Bookmark{
+		Key: key, Site: "demonic", SeriesID: "Catastrophic-Necromancer",
+		SeriesURL: url, LatestChapter: "Chapter 400", LatestChapterNum: &high,
+		UpdatedAt: 1000,
+	}); err != nil {
+		t.Fatalf("seed: %v", err)
+	}
+
+	f := &fakeFetcher{body: demonicSeriesFixture, status: 200}
+	newTestPoller(t, s, f, time.UnixMilli(5_000_000)).runOnce(context.Background())
+
+	b, _, err := s.Get(key)
+	if err != nil {
+		t.Fatalf("Get: %v", err)
+	}
+	if b.LatestChapterNum == nil || *b.LatestChapterNum != 296 {
+		t.Fatalf("LatestChapterNum = %v, want 296", b.LatestChapterNum)
+	}
+}
+
+// A cancelled context must abandon the batch rather than run it to completion.
+func TestRunOnceStopsOnCancelledContext(t *testing.T) {
+	s := newTestStore(t)
+	for _, k := range []string{"asura:a", "asura:b", "asura:c"} {
+		seedForCheck(t, s, k, "https://asurascans.com/comics/"+k, 0)
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+
+	f := &fakeFetcher{body: "", status: 200}
+	newTestPoller(t, s, f, time.UnixMilli(5_000_000)).runOnce(ctx)
+
+	if got := f.callCount(); got != 0 {
+		t.Fatalf("fetched %d series with a cancelled context, want 0", got)
+	}
+}