move nostr-sdk repository into here because why not?

sdk/hints/memory/memory_hints.go

@@ -0,0 +1,142 @@
+package memory
+
+import (
+	"fmt"
+	"math"
+	"slices"
+	"sync"
+
+	"github.com/nbd-wtf/go-nostr"
+	"github.com/nbd-wtf/go-nostr/sdk/hints"
+)
+
+var _ hints.HintsDB = (*HintDB)(nil)
+
+type HintDB struct {
+	RelayBySerial         []string
+	OrderedRelaysByPubKey map[string]RelaysForPubKey
+
+	sync.Mutex
+}
+
+func NewHintDB() *HintDB {
+	return &HintDB{
+		RelayBySerial:         make([]string, 0, 100),
+		OrderedRelaysByPubKey: make(map[string]RelaysForPubKey, 100),
+	}
+}
+
+func (db *HintDB) Save(pubkey string, relay string, key hints.HintKey, ts nostr.Timestamp) {
+	now := nostr.Now()
+	// this is used for calculating what counts as a usable hint
+	threshold := (now - 60*60*24*180)
+	if threshold < 0 {
+		threshold = 0
+	}
+
+	relayIndex := slices.Index(db.RelayBySerial, relay)
+	if relayIndex == -1 {
+		relayIndex = len(db.RelayBySerial)
+		db.RelayBySerial = append(db.RelayBySerial, relay)
+	}
+
+	db.Lock()
+	defer db.Unlock()
+	// fmt.Println(" ", relay, "index", relayIndex, "--", "adding", hints.HintKey(key).String(), ts)
+
+	rfpk, _ := db.OrderedRelaysByPubKey[pubkey]
+
+	entries := rfpk.Entries
+
+	entryIndex := slices.IndexFunc(entries, func(re RelayEntry) bool { return re.Relay == relayIndex })
+	if entryIndex == -1 {
+		// we don't have an entry for this relay, so add one
+		entryIndex = len(entries)
+
+		entry := RelayEntry{
+			Relay: relayIndex,
+		}
+		entry.Timestamps[key] = ts
+
+		entries = append(entries, entry)
+	} else {
+		// just update this entry
+		if entries[entryIndex].Timestamps[key] < ts {
+			entries[entryIndex].Timestamps[key] = ts
+		} else {
+			// no need to update anything
+			return
+		}
+	}
+
+	rfpk.Entries = entries
+
+	db.OrderedRelaysByPubKey[pubkey] = rfpk
+}
+
+func (db *HintDB) TopN(pubkey string, n int) []string {
+	db.Lock()
+	defer db.Unlock()
+
+	urls := make([]string, 0, n)
+	if rfpk, ok := db.OrderedRelaysByPubKey[pubkey]; ok {
+		// sort everything from scratch
+		slices.SortFunc(rfpk.Entries, func(a, b RelayEntry) int {
+			return int(b.Sum() - a.Sum())
+		})
+
+		for i, re := range rfpk.Entries {
+			urls = append(urls, db.RelayBySerial[re.Relay])
+			if i+1 == n {
+				break
+			}
+		}
+	}
+	return urls
+}
+
+func (db *HintDB) PrintScores() {
+	db.Lock()
+	defer db.Unlock()
+
+	fmt.Println("= print scores")
+	for pubkey, rfpk := range db.OrderedRelaysByPubKey {
+		fmt.Println("== relay scores for", pubkey)
+		for i, re := range rfpk.Entries {
+			fmt.Printf("  %3d :: %30s (%3d) ::> %12d\n", i, db.RelayBySerial[re.Relay], re.Relay, re.Sum())
+		}
+	}
+}
+
+type RelaysForPubKey struct {
+	Entries []RelayEntry
+}
+
+type RelayEntry struct {
+	Relay      int
+	Timestamps [8]nostr.Timestamp
+}
+
+func (re RelayEntry) Sum() int64 {
+	now := nostr.Now() + 24*60*60
+	var sum int64
+	for i, ts := range re.Timestamps {
+		if ts == 0 {
+			continue
+		}
+
+		hk := hints.HintKey(i)
+		divisor := int64(now - ts)
+		if divisor == 0 {
+			divisor = 1
+		} else {
+			divisor = int64(math.Pow(float64(divisor), 1.3))
+		}
+
+		multiplier := hk.BasePoints()
+		value := multiplier * 10000000000 / divisor
+		// fmt.Println("   ", i, "value:", value)
+		sum += value
+	}
+	return sum
+}