From b0ab2ed92870d8c651267db10d68eb695da2ec62 Mon Sep 17 00:00:00 2001
From: SayaAndy <saya.andy@posteo.com>
Date: Tue, 26 Aug 2025 23:41:00 +0700
Subject: feat: like button (only inmem-cache for now)

---
 internal/router/client-cache.go | 82 +++++++++++++++++++++++++++++++++--------
 1 file changed, 66 insertions(+), 16 deletions(-)

(limited to 'internal/router/client-cache.go')

diff --git a/internal/router/client-cache.go b/internal/router/client-cache.go
index a4a0cc2..3104a66 100644
--- a/internal/router/client-cache.go
+++ b/internal/router/client-cache.go
@@ -9,40 +9,90 @@ import (
 )
 
 type ClientCache struct {
-	hashMap  map[string][]byte
-	mutexMap map[string]*sync.Mutex
-	salt     []byte
+	hashMap      map[string]string
+	mutexLikeMap map[string]*sync.Mutex
+	mutexHashMap map[string]*sync.Mutex
+	likePageMap  map[string]map[string]struct{}
+	salt         []byte
 }
 
 var CCache *ClientCache
 
 func NewClientCache(salt []byte) *ClientCache {
 	return &ClientCache{
-		hashMap:  make(map[string][]byte),
-		mutexMap: make(map[string]*sync.Mutex),
-		salt:     salt,
+		hashMap:      make(map[string]string),
+		mutexLikeMap: make(map[string]*sync.Mutex),
+		mutexHashMap: make(map[string]*sync.Mutex),
+		likePageMap:  make(map[string]map[string]struct{}),
+		salt:         salt,
 	}
 }
 
-func (c *ClientCache) GetHash(id string) []byte {
-
+func (c *ClientCache) GetHash(id string) string {
 	if val, ok := c.hashMap[id]; ok {
-		slog.Debug("gave an old hash", slog.String("hash", base64.RawStdEncoding.EncodeToString(val)))
+		slog.Debug("gave an old hash", slog.String("hash", val))
 		return val
 	}
 
-	if _, ok := c.mutexMap[id]; !ok {
-		c.mutexMap[id] = &sync.Mutex{}
+	if _, ok := c.mutexHashMap[id]; !ok {
+		c.mutexHashMap[id] = &sync.Mutex{}
 	}
-	c.mutexMap[id].Lock()
-	defer c.mutexMap[id].Unlock()
+	c.mutexHashMap[id].Lock()
+	defer c.mutexHashMap[id].Unlock()
 
 	if val, ok := c.hashMap[id]; ok {
-		slog.Debug("gave a newly generated hash", slog.String("hash", base64.RawStdEncoding.EncodeToString(val)))
+		slog.Debug("gave a newly generated hash", slog.String("hash", val))
 		return val
 	}
 
-	c.hashMap[id] = argon2.IDKey([]byte(id), c.salt, 1, 64*1024, 4, 32)
-	slog.Debug("generated hash", slog.String("hash", base64.RawStdEncoding.EncodeToString(c.hashMap[id])))
+	c.hashMap[id] = base64.RawStdEncoding.EncodeToString(argon2.IDKey([]byte(id), c.salt, 1, 64*1024, 4, 32))
+	slog.Debug("generated hash", slog.String("hash", c.hashMap[id]))
 	return c.hashMap[id]
 }
+
+func (c *ClientCache) GetLikeStatus(id string, page string) bool {
+	if _, ok := c.likePageMap[page]; !ok {
+		return false
+	}
+	_, ok := c.likePageMap[page][c.GetHash(id)]
+	return ok
+}
+
+func (c *ClientCache) LikeOn(id string, page string) (alreadyLiked bool) {
+	if _, ok := c.mutexLikeMap[id]; !ok {
+		c.mutexLikeMap[id] = &sync.Mutex{}
+	}
+	c.mutexLikeMap[id].Lock()
+	defer c.mutexLikeMap[id].Unlock()
+
+	hash := c.GetHash(id)
+
+	if userSet, ok := c.likePageMap[page]; ok {
+		_, alreadyLiked = userSet[hash]
+		c.likePageMap[page][hash] = struct{}{}
+		return
+	}
+
+	c.likePageMap[page] = make(map[string]struct{})
+	c.likePageMap[page][hash] = struct{}{}
+	return
+}
+
+func (c *ClientCache) LikeOff(id string, page string) (alreadyUnliked bool) {
+	if _, ok := c.mutexLikeMap[id]; !ok {
+		c.mutexLikeMap[id] = &sync.Mutex{}
+	}
+	c.mutexLikeMap[id].Lock()
+	defer c.mutexLikeMap[id].Unlock()
+
+	if _, ok := c.likePageMap[page]; !ok {
+		return true
+	}
+	hash := c.GetHash(id)
+	if _, ok := c.likePageMap[page][hash]; !ok {
+		return true
+	}
+
+	delete(c.likePageMap[page], hash)
+	return false
+}
-- 
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