commit 4f291c93e5e3a44aa58da16f64d69978be8ff1bf
Author: tijl <contact@tijl.dev>
Date:   Wed Aug 6 10:23:12 2025 +0200

    first commit

diff --git a/client.go b/client.go
new file mode 100644
index 0000000..c7e67c7
--- /dev/null
+++ b/client.go
@@ -0,0 +1,72 @@
+package shortify
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"io"
+	"net"
+	"net/http"
+	"time"
+)
+
+type ClientConfig struct {
+	UseUnixSocket bool   // true = unix socket, false = http
+	SocketPath    string // e.g. /tmp/shorty.sock
+	HTTPAddress   string // e.g. http://localhost:8080
+	Timeout       time.Duration
+}
+
+type Client struct {
+	httpClient *http.Client
+	baseURL    string
+}
+
+func NewClient(cfg ClientConfig) (*Client, error) {
+	transport := &http.Transport{}
+
+	if cfg.UseUnixSocket {
+		dialer := func(_ context.Context, _, _ string) (net.Conn, error) {
+			return net.Dial("unix", cfg.SocketPath)
+		}
+		transport.DialContext = dialer
+		cfg.HTTPAddress = "http://unix" // dummy for request building
+	}
+
+	client := &http.Client{
+		Transport: transport,
+		Timeout:   cfg.Timeout,
+	}
+
+	return &Client{
+		httpClient: client,
+		baseURL:    cfg.HTTPAddress,
+	}, nil
+}
+
+func (c *Client) Shorten(url string) (string, error) {
+	body := []byte(url)
+
+	req, err := http.NewRequest("POST", c.baseURL+"/s", bytes.NewReader(body))
+	if err != nil {
+		return "", err
+	}
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		b, _ := io.ReadAll(resp.Body)
+		return "", errors.New("shorten failed: " + string(b))
+	}
+
+	result, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return "", err
+	}
+
+	return string(result), nil
+}
diff --git a/examples/main.go b/examples/main.go
new file mode 100644
index 0000000..3859832
--- /dev/null
+++ b/examples/main.go
@@ -0,0 +1,19 @@
+package main
+
+import (
+	"git.tijl.dev/tijl/shortify"
+)
+
+func main() {
+	s, err := shortify.NewShortener(shortify.Config{
+		DataFolder:    "./shortify",
+		CacheSize:     10000,
+		AccessLogSize: 10000,
+	})
+	if err != nil {
+		panic(err)
+	}
+
+	go s.ServeSocket("./data/shortify.sock")
+	s.ServeHTTP("0.0.0.0:3001")
+}
diff --git a/generation.go b/generation.go
new file mode 100644
index 0000000..fb870d5
--- /dev/null
+++ b/generation.go
@@ -0,0 +1,218 @@
+package shortify
+
+import (
+	"crypto/rand"
+	"errors"
+	"log"
+	"math/big"
+	"sync"
+	"time"
+
+	"go.etcd.io/bbolt"
+)
+
+type IDPool struct {
+	db           *bbolt.DB
+	mu           sync.Mutex
+	idLen        int
+	poolCap      int
+	regenThresh  int
+	inMemoryPool []string
+	cond         *sync.Cond
+	stopCh       chan struct{}
+	usedChan     chan string
+}
+
+func NewIDPool(db *bbolt.DB, idLen int, poolCap int, regenThresh int) (*IDPool, error) {
+	p := &IDPool{
+		db:          db,
+		idLen:       idLen,
+		poolCap:     poolCap,
+		regenThresh: regenThresh,
+		stopCh:      make(chan struct{}),
+		usedChan:    make(chan string, 1000),
+	}
+	p.cond = sync.NewCond(&p.mu)
+
+	err := db.Update(func(tx *bbolt.Tx) error {
+		_, err := tx.CreateBucketIfNotExists(idpoolBucket)
+		return err
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	if err := p.loadFromDB(); err != nil {
+		return nil, err
+	}
+
+	if len(p.inMemoryPool) == 0 {
+		// idpool empty at startup, generating initial batch...
+		if err := p.GenerateBatch(); err != nil {
+			return nil, err
+		}
+		if err := p.loadFromDB(); err != nil {
+			return nil, err
+		}
+	}
+
+	go p.backgroundGenerator()
+	go p.flushUsedIDs()
+
+	return p, nil
+}
+
+func (p *IDPool) loadFromDB() error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	var ids []string
+
+	err := p.db.View(func(tx *bbolt.Tx) error {
+		b := tx.Bucket(idpoolBucket)
+		if b == nil {
+			return nil
+		}
+
+		c := b.Cursor()
+		for k, _ := c.First(); k != nil; k, _ = c.Next() {
+			ids = append(ids, string(k))
+		}
+		return nil
+	})
+
+	if err != nil {
+		return err
+	}
+
+	p.inMemoryPool = ids
+	return nil
+}
+
+func (p *IDPool) GenerateBatch() error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	return p.db.Update(func(tx *bbolt.Tx) error {
+		b := tx.Bucket(idpoolBucket)
+		count := b.Stats().KeyN
+		for count < p.poolCap {
+			id, err := generateID(p.idLen)
+			if err != nil {
+				return err
+			}
+			if b.Get([]byte(id)) != nil {
+				continue
+			}
+			if err := b.Put([]byte(id), []byte{}); err != nil {
+				return err
+			}
+			count++
+		}
+		return nil
+	})
+}
+
+// PopID returns an ID from memory and queues it for async DB removal
+func (p *IDPool) PopID() (string, error) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	if len(p.inMemoryPool) == 0 {
+		return "", errors.New("id pool empty")
+	}
+
+	// Fast O(1) pop
+	id := p.inMemoryPool[0]
+	p.inMemoryPool = p.inMemoryPool[1:]
+
+	// Queue for async delete
+	select {
+	case p.usedChan <- id:
+	default:
+		// If the channel is full, we drop the delete. Risky only if shutdown happens
+		log.Println("Warning: used ID queue full; delete may be delayed")
+	}
+
+	// Signal for batch regen if low
+	if len(p.inMemoryPool) < p.regenThresh {
+		p.cond.Signal()
+	}
+
+	return id, nil
+}
+
+func (p *IDPool) backgroundGenerator() {
+	for {
+		p.mu.Lock()
+		for len(p.inMemoryPool) >= p.regenThresh {
+			p.cond.Wait()
+		}
+		p.mu.Unlock()
+
+		select {
+		case <-p.stopCh:
+			return
+		default:
+		}
+
+		// generating batch
+		err := p.GenerateBatch()
+		if err != nil {
+			// error generating batch:(
+			time.Sleep(time.Second * 5)
+			continue
+		}
+		if err := p.loadFromDB(); err != nil {
+			// error laoding from db:(
+		}
+	}
+}
+
+func (p *IDPool) flushUsedIDs() {
+	for {
+		select {
+		case <-p.stopCh:
+			return
+		case id := <-p.usedChan:
+			err := p.db.Update(func(tx *bbolt.Tx) error {
+				b := tx.Bucket(idpoolBucket)
+				return b.Delete([]byte(id))
+			})
+			if err != nil {
+				log.Printf("Failed to delete used ID %s: %v\n", id, err)
+			}
+		}
+	}
+}
+
+func (p *IDPool) Stop() {
+	close(p.stopCh)
+	// Drain and flush remaining used IDs
+	for {
+		select {
+		case id := <-p.usedChan:
+			p.db.Update(func(tx *bbolt.Tx) error {
+				b := tx.Bucket(idpoolBucket)
+				return b.Delete([]byte(id))
+			})
+		default:
+			return
+		}
+	}
+}
+
+var idpoolBucket = []byte("idpool")
+var base62 = []rune("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz")
+
+func generateID(n int) (string, error) {
+	id := make([]rune, n)
+	for i := range id {
+		num, err := rand.Int(rand.Reader, big.NewInt(int64(len(base62))))
+		if err != nil {
+			return "", err
+		}
+		id[i] = base62[num.Int64()]
+	}
+	return string(id), nil
+}
diff --git a/global.go b/global.go
new file mode 100644
index 0000000..f5543ec
--- /dev/null
+++ b/global.go
@@ -0,0 +1,35 @@
+package shortify
+
+import (
+	"sync"
+
+	"go.etcd.io/bbolt"
+)
+
+// Global instance
+var (
+	Global *Shortener
+	once   sync.Once
+)
+
+func Init(cfg Config) error {
+	var err error
+	once.Do(func() {
+		Global, err = NewShortener(cfg)
+	})
+	return err
+}
+
+// Global instance (duc)
+var (
+	GlobalIDPool *IDPool
+	oncePopper   sync.Once
+)
+
+func InitIDPool(db *bbolt.DB, idLen, poolCap, regenThresh int) error {
+	var err error
+	oncePopper.Do(func() {
+		GlobalIDPool, err = NewIDPool(db, idLen, poolCap, regenThresh)
+	})
+	return err
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..2538c65
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module git.tijl.dev/tijl/shortify
+
+go 1.24.3
diff --git a/logger.go b/logger.go
new file mode 100644
index 0000000..e494edd
--- /dev/null
+++ b/logger.go
@@ -0,0 +1,72 @@
+package shortify
+
+import (
+	"database/sql"
+	"fmt"
+	"time"
+
+	_ "github.com/marcboeker/go-duckdb/v2"
+)
+
+type VisitLog struct {
+	ShortID string
+	LongURL string
+
+	IP string
+
+	UserAgent string
+	Referer   string
+	Language  string
+
+	Time time.Time
+}
+
+func (s *Shortener) LogVisit(log VisitLog) {
+	s.logChan <- log
+}
+
+func (s *Shortener) startLogging() {
+
+	db, err := sql.Open("duckdb", s.DataFolder+"/analytics.db")
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	defer db.Close()
+
+	_, err = db.Exec(`
+CREATE SEQUENCE IF NOT EXISTS seq_visitid START 1;
+CREATE TABLE IF NOT EXISTS visits (
+    id INTEGER PRIMARY KEY,
+    shortid VARCHAR,
+    longurl VARCHAR,
+    ip VARCHAR,
+    useragent VARCHAR,
+    referer VARCHAR,
+    language VARCHAR,
+    time TIMESTAMP
+);
+		`)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	stmt, err := db.Prepare(`
+    INSERT INTO visits (id, shortid, longurl, ip, useragent, referer, language, time)
+    VALUES (nextval('seq_visitid'), ?, ?, ?, ?, ?, ?, ?)
+`)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	defer stmt.Close()
+
+	for log := range s.logChan {
+		_, err = stmt.Exec(log.ShortID, log.LongURL, log.IP, log.UserAgent, log.Referer, log.Language, log.Time)
+		if err != nil {
+			fmt.Println(err)
+			return
+		}
+	}
+}
diff --git a/server.go b/server.go
new file mode 100644
index 0000000..44c31d2
--- /dev/null
+++ b/server.go
@@ -0,0 +1,122 @@
+package shortify
+
+import (
+	"errors"
+	"log"
+	"net"
+	"os"
+	"time"
+
+	"github.com/gofiber/fiber/v2"
+)
+
+// wow
+func (s *Shortener) ServeSocket(path string) {
+
+	// Remove old socket if exists
+	socketPath := path
+	_ = os.Remove(socketPath)
+
+	// Create a Unix socket listener
+	ln, err := net.Listen("unix", socketPath)
+	if err != nil {
+		log.Fatalf("Failed to listen on unix socket: %v", err)
+	}
+
+	// Optionally set permissions so other processes can connect
+	_ = os.Chmod(socketPath, 0666)
+
+	app := fiber.New()
+
+	app.Post("/s", s.HandlePOSTShortURLDirect())
+
+	log.Fatal(app.Listener(ln))
+}
+func (s *Shortener) ServeHTTP(addr string) {
+	app := fiber.New()
+
+	app.Get("/s/:id", s.HandleGETShortURL())
+
+	log.Fatal(app.Listen(addr))
+}
+
+func (s *Shortener) NewShortURL(longUrl string) string {
+	shortID, err := s.idPool.PopID()
+	if err != nil {
+		return ""
+	}
+
+	err = s.put(shortID, longUrl)
+	if err != nil {
+		return ""
+	}
+
+	return shortID
+}
+
+func (s *Shortener) HandleGETShortURL() func(*fiber.Ctx) error {
+	return func(c *fiber.Ctx) error {
+		shortID := c.Params("id")
+
+		url, err := s.get(shortID)
+		if err != nil {
+			return err
+		}
+
+		s.LogVisit(VisitLog{
+			ShortID: shortID,
+			LongURL: url,
+
+			IP: c.IP(),
+
+			UserAgent: string(c.Context().UserAgent()),
+			Language:  c.GetReqHeaders()["Accept-Language"][0],
+			Referer:   string(c.Request().Header.Referer()),
+
+			Time: time.Now(),
+		})
+
+		c.Set("Referrer-Policy", "no-referrer")
+		return c.Redirect(url, fiber.StatusFound)
+	}
+}
+
+func (s *Shortener) HandlePOSTShortURL() func(*fiber.Ctx) error {
+	return func(c *fiber.Ctx) error {
+		longUrl := string(c.Body())
+
+		if longUrl == "" {
+			return errors.New("whut")
+		}
+
+		shortID, err := s.idPool.PopID()
+		if err != nil {
+			return err
+		}
+
+		err = s.put(shortID, longUrl)
+		if err != nil {
+			return err
+		}
+
+		return c.SendString(shortID)
+	}
+}
+
+func (s *Shortener) HandlePOSTShortURLDirect() func(*fiber.Ctx) error {
+	return func(c *fiber.Ctx) error {
+		longUrl := string(c.Body())
+		shortID := c.Query("s")
+
+		if longUrl == "" || shortID == "" {
+			return errors.New("no comment")
+		}
+
+		err := s.put(shortID, longUrl)
+		if err != nil {
+			return err
+		}
+
+		return c.SendString(shortID)
+	}
+}
diff --git a/shortify.go b/shortify.go
new file mode 100644
index 0000000..24d73d5
--- /dev/null
+++ b/shortify.go
@@ -0,0 +1,58 @@
+package shortify
+
+import (
+	"sync"
+
+	"github.com/hashicorp/golang-lru"
+	bolt "go.etcd.io/bbolt"
+)
+
+type Shortener struct {
+	DataFolder string
+
+	db          *bolt.DB
+	cache       *lru.Cache
+	accessCache *lru.Cache
+	logChan     chan VisitLog
+	idPool      *IDPool
+
+	writeChan chan [2]string // queue of writes: [shortID, longURL]
+	memStore  sync.Map       // thread-safe built-in
+
+}
+
+type Config struct {
+	DataFolder    string
+	CacheSize     int
+	AccessLogSize int
+}
+
+func NewShortener(cfg Config) (*Shortener, error) {
+	db, err := bolt.Open(cfg.DataFolder+"/database.db", 0600, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	urlCache, _ := lru.New(cfg.CacheSize)
+	accessCache, _ := lru.New(cfg.AccessLogSize)
+
+	idPool, err := NewIDPool(db, 8, 10000, 2000)
+	if err != nil {
+		return nil, err
+	}
+
+	s := &Shortener{
+		DataFolder:  cfg.DataFolder,
+		db:          db,
+		cache:       urlCache,
+		accessCache: accessCache,
+		logChan:     make(chan VisitLog, 1000),
+		writeChan:   make(chan [2]string, 1000),
+		idPool:      idPool,
+	}
+
+	go s.startLogging()
+	go s.asyncDBWriter()
+
+	return s, nil
+}
diff --git a/storage.go b/storage.go
new file mode 100644
index 0000000..ec77850
--- /dev/null
+++ b/storage.go
@@ -0,0 +1,71 @@
+package shortify
+
+import (
+	"errors"
+	"log"
+
+	"go.etcd.io/bbolt"
+)
+
+var bucketName = []byte("shorturls")
+
+func (s *Shortener) get(shortID string) (string, error) {
+	if val, ok := s.memStore.Load(shortID); ok {
+		s.cache.Add(shortID, val.(string))
+		return val.(string), nil
+	}
+
+	if val, ok := s.cache.Get(shortID); ok {
+		return val.(string), nil
+	}
+
+	var longURL string
+	err := s.db.View(func(tx *bbolt.Tx) error {
+		b := tx.Bucket(bucketName)
+		if b == nil {
+			return errors.New("not found")
+		}
+		v := b.Get([]byte(shortID))
+		if v != nil {
+			longURL = string(v)
+			s.cache.Add(shortID, longURL)
+			return nil
+		}
+		return errors.New("not found")
+	})
+
+	return longURL, err
+}
+
+func (s *Shortener) put(shortID, longURL string) error {
+
+	s.memStore.Store(shortID, longURL)
+	s.cache.Add(shortID, longURL)
+
+	// Queue write to DB (non-blocking)
+	select {
+	case s.writeChan <- [2]string{shortID, longURL}:
+	default:
+		log.Println("Warning: write queue full, short URL write may be dropped")
+	}
+
+	return nil
+}
+
+func (s *Shortener) asyncDBWriter() {
+	for pair := range s.writeChan {
+		shortID := pair[0]
+		longURL := pair[1]
+
+		err := s.db.Update(func(tx *bbolt.Tx) error {
+			b, err := tx.CreateBucketIfNotExists(bucketName)
+			if err != nil {
+				return err
+			}
+			return b.Put([]byte(shortID), []byte(longURL))
+		})
+		if err != nil {
+			log.Printf("DB write failed for %s: %v", shortID, err)
+		}
+	}
+}