usercache: we'll do it ourselves

we don't need expr or anything like that, cmp.Less and vim macros exist.

usercache.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"cmp"
 	"sync"
 	"time"
 )
@@ -17,6 +18,7 @@ type UserCache struct {
 }
 
 func (c *UserCache) Gen(app *appContext) error {
+	c.Lock.Lock()
 	if !time.Now().After(c.LastSync.Add(WEB_USER_CACHE_SYNC)) {
 		return nil
 	}
@@ -24,7 +26,6 @@ func (c *UserCache) Gen(app *appContext) error {
 	if err != nil {
 		return err
 	}
-	c.Lock.Lock()
 	c.Cache = make([]respUser, len(users))
 	for i, jfUser := range users {
 		c.Cache[i] = app.userSummary(jfUser)
@@ -33,3 +34,116 @@ func (c *UserCache) Gen(app *appContext) error {
 	c.Lock.Unlock()
 	return nil
 }
+
+type SortableUserList struct {
+	Cache    []respUser
+	lessFunc func(a, b *respUser) bool
+}
+
+func (sc *SortableUserList) Len() int {
+	return len(sc.Cache)
+}
+
+func (sc *SortableUserList) Swap(i, j int) {
+	sc.Cache[i], sc.Cache[j] = sc.Cache[j], sc.Cache[i]
+}
+
+func (sc *SortableUserList) Less(i, j int) bool {
+	return sc.lessFunc(&sc.Cache[i], &sc.Cache[j])
+}
+
+// instead of making a Less for bools, just convert them to integers
+// https://0x0f.me/blog/golang-compiler-optimization/
+func bool2int(b bool) int {
+	var i int
+	if b {
+		i = 1
+	} else {
+		i = 0
+	}
+	return i
+}
+
+// Allow sorting by respUser's struct fields (well, it's JSON-representation's fields)
+// Ugly I know, but at least cmp.Less exists.
+// Done with vim macros, thank god they exist
+func SortUsersBy(u []respUser, field string) SortableUserList {
+	s := SortableUserList{Cache: u}
+
+	switch field {
+	case "id":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(a.ID, b.ID)
+		}
+
+	case "name":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(a.Name, b.Name)
+		}
+	case "email":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(a.Email, b.Email)
+		}
+	case "notify_email":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(bool2int(a.NotifyThroughEmail), bool2int(b.NotifyThroughEmail))
+		}
+	case "last_active":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(a.LastActive, b.LastActive)
+		}
+	case "admin":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(bool2int(a.Admin), bool2int(b.Admin))
+		}
+	case "expiry":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(a.Expiry, b.Expiry)
+		}
+	case "disabled":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(bool2int(a.Disabled), bool2int(b.Disabled))
+		}
+	case "telegram":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(a.Telegram, b.Telegram)
+		}
+	case "notify_telegram":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(bool2int(a.NotifyThroughTelegram), bool2int(b.NotifyThroughTelegram))
+		}
+	case "discord":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(a.Discord, b.Discord)
+		}
+	case "discord_id":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(a.DiscordID, b.DiscordID)
+		}
+	case "notify_discord":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(bool2int(a.NotifyThroughDiscord), bool2int(b.NotifyThroughDiscord))
+		}
+	case "matrix":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(a.Matrix, b.Matrix)
+		}
+	case "notify_matrix":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(bool2int(a.NotifyThroughMatrix), bool2int(b.NotifyThroughMatrix))
+		}
+	case "label":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(a.Label, b.Label)
+		}
+	case "accounts_admin":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(bool2int(a.AccountsAdmin), bool2int(b.AccountsAdmin))
+		}
+	case "referrals_enabled":
+		s.lessFunc = func(a, b *respUser) bool {
+			return cmp.Less(bool2int(a.ReferralsEnabled), bool2int(b.ReferralsEnabled))
+		}
+	}
+	return s
+}