feat(story-2.4-2.5): add article handler, background fetcher worker

internal/worker/fetcher.go

@@ -0,0 +1,78 @@
+// Package worker provides background job processing.
+package worker
+
+import (
+	"context"
+	"log"
+	"sync"
+	"time"
+
+	"github.com/michael/flowreader/internal/service"
+)
+
+// FeedFetcher handles periodic feed fetching.
+type FeedFetcher struct {
+	fetchService *service.FetchService
+	interval     time.Duration
+	concurrency  int
+	stopCh       chan struct{}
+	wg           sync.WaitGroup
+}
+
+// NewFeedFetcher creates a new feed fetcher worker.
+func NewFeedFetcher(fetchService *service.FetchService, interval time.Duration, concurrency int) *FeedFetcher {
+	return &FeedFetcher{
+		fetchService: fetchService,
+		interval:     interval,
+		concurrency:  concurrency,
+		stopCh:       make(chan struct{}),
+	}
+}
+
+// Start begins the background fetch loop.
+func (f *FeedFetcher) Start() {
+	f.wg.Add(1)
+	go f.run()
+	log.Printf("Feed fetcher started (interval: %s, concurrency: %d)", f.interval, f.concurrency)
+}
+
+// Stop gracefully stops the fetcher.
+func (f *FeedFetcher) Stop() {
+	close(f.stopCh)
+	f.wg.Wait()
+	log.Println("Feed fetcher stopped")
+}
+
+func (f *FeedFetcher) run() {
+	defer f.wg.Done()
+
+	// Initial fetch on startup
+	f.fetch()
+
+	ticker := time.NewTicker(f.interval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ticker.C:
+			f.fetch()
+		case <-f.stopCh:
+			return
+		}
+	}
+}
+
+func (f *FeedFetcher) fetch() {
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Minute)
+	defer cancel()
+
+	count, err := f.fetchService.FetchAllPending(ctx, f.concurrency)
+	if err != nil {
+		log.Printf("Feed fetch error: %v", err)
+		return
+	}
+
+	if count > 0 {
+		log.Printf("Fetched %d feeds", count)
+	}
+}