1 files changed, 166 insertions, 0 deletions
diff --git a/fetchers/cache.go b/fetchers/cache.go
new file mode 100644
index 0000000..dc43c53
--- /dev/null
+++ b/fetchers/cache.go
@@ -0,0 +1,166 @@
+package fetchers
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"llostre/notes"
+	"sort"
+	"time"
+
+	"github.com/redis/go-redis/v9"
+)
+
+type Cache struct {
+	client     *redis.Client
+	ctx        context.Context
+	expiryTime time.Duration
+}
+
+func NewCache(addr, password string, expiryMinutes int) (*Cache, error) {
+	client := redis.NewClient(&redis.Options{
+		Addr:     addr,
+		Password: password,
+		DB:       0,
+	})
+
+	ctx := context.Background()
+	if err := client.Ping(ctx).Err(); err != nil {
+		return nil, fmt.Errorf("redis connection failed: %w", err)
+	}
+
+	return &Cache{
+		client:     client,
+		ctx:        ctx,
+		expiryTime: time.Duration(expiryMinutes) * time.Minute,
+	}, nil
+}
+
+func (c *Cache) Get(uri string) (*notes.Note, bool) {
+	key := fmt.Sprintf("post:%s", uri)
+	data, err := c.client.Get(c.ctx, key).Bytes()
+	if err != nil {
+		return nil, false
+	}
+
+	var note notes.Note
+	if err := json.Unmarshal(data, &note); err != nil {
+		return nil, false
+	}
+
+	return &note, true
+}
+
+func (c *Cache) Set(uri string, note *notes.Note) {
+	key := fmt.Sprintf("post:%s", uri)
+	data, err := json.Marshal(note)
+	if err != nil {
+		return
+	}
+
+	c.client.Set(c.ctx, key, data, c.expiryTime)
+}
+
+func (c *Cache) GetAuthor(did string) (*notes.Author, bool) {
+	key := fmt.Sprintf("profile:%s", did)
+	data, err := c.client.Get(c.ctx, key).Bytes()
+	if err != nil {
+		return nil, false
+	}
+
+	var author notes.Author
+	if err := json.Unmarshal(data, &author); err != nil {
+		return nil, false
+	}
+
+	return &author, true
+}
+
+func (c *Cache) SetAuthor(did string, author *notes.Author) {
+	key := fmt.Sprintf("profile:%s", did)
+	data, err := json.Marshal(author)
+	if err != nil {
+		return
+	}
+
+	c.client.Set(c.ctx, key, data, c.expiryTime)
+}
+
+func (c *Cache) GetCursor(did string) (string, bool) {
+	key := fmt.Sprintf("cursor:%s", did)
+	cursor, err := c.client.Get(c.ctx, key).Result()
+	if err != nil {
+		return "", false
+	}
+	return cursor, true
+}
+
+func (c *Cache) SetCursor(did, cursor string) {
+	key := fmt.Sprintf("cursor:%s", did)
+	if cursor == "" {
+		c.client.Del(c.ctx, key)
+		return
+	}
+	c.client.Set(c.ctx, key, cursor, 24*time.Hour)
+}
+
+func (c *Cache) GetPostsByDID(did string) ([]notes.Note, error) {
+	pattern := fmt.Sprintf("post:at://%s/*", did)
+	var posts []notes.Note
+
+	iter := c.client.Scan(c.ctx, 0, pattern, 0).Iterator()
+	for iter.Next(c.ctx) {
+		data, err := c.client.Get(c.ctx, iter.Val()).Bytes()
+		if err != nil {
+			continue
+		}
+		var note notes.Note
+		if err := json.Unmarshal(data, &note); err != nil {
+			continue
+		}
+		posts = append(posts, note)
+	}
+
+	if err := iter.Err(); err != nil {
+		return nil, err
+	}
+
+	sort.Slice(posts, func(i, j int) bool {
+		return posts[i].CreatedAt.After(posts[j].CreatedAt)
+	})
+
+	return posts, nil
+}
+
+// track oldest sent post per profile
+func (c *Cache) GetOldestSent(did string) (time.Time, bool) {
+	key := fmt.Sprintf("oldest_sent:%s", did)
+	ts, err := c.client.Get(c.ctx, key).Int64()
+	if err != nil {
+		return time.Time{}, false
+	}
+	return time.Unix(ts, 0), true
+}
+
+func (c *Cache) SetOldestSent(did string, timestamp time.Time) {
+	key := fmt.Sprintf("oldest_sent:%s", did)
+	c.client.Set(c.ctx, key, timestamp.Unix(), 24*time.Hour)
+}
+
+// count posts older than timestamp for a profile
+func (c *Cache) CountPostsOlderThan(did string, timestamp time.Time) (int, error) {
+	posts, err := c.GetPostsByDID(did)
+	if err != nil {
+		return 0, err
+	}
+	for i, p := range posts {
+		if p.CreatedAt.Before(timestamp) {
+			return len(posts) - i, nil
+		}
+	}
+	return 0, nil
+}
+
+func (c *Cache) Close() error {
+	return c.client.Close()
+}