Fix fuzzyCompare

backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/command/description/CommandArgParserBuiltins.kt

@@ -195,12 +195,15 @@ public object ExistMemberArgumentParser : InternalCommandArgumentParserExtension
          - `botId.group.memberId`
          - `botId.group.memberCard` (模糊搜索, 寻找最优匹配)
          - `~` (指代指令调用人自己. 仅聊天环境下)
+         - `$` (随机成员)
          
          当只登录了一个 [Bot] 时, 无需上述 `botId` 参数即可
     """.trimIndent()
 
     public override fun parse(raw: String, sender: CommandSender): Member {
-        if (raw == "~") return (sender as? MemberCommandSender)?.user ?: illegalArgument("当前语境下无法推断目标群员")
+        if (raw == "~") return (sender as? MemberCommandSender)?.user ?: illegalArgument("当前语境下无法推断自身作为群员")
+        if (raw == "\$") return (sender as? MemberCommandSender)?.group?.members?.randomOrNull()
+            ?: illegalArgument("当前语境下无法推断随机群员")
 
         val components = raw.split(".")
 
@@ -221,7 +224,12 @@ public object ExistMemberArgumentParser : InternalCommandArgumentParserExtension
     public override fun parse(raw: SingleMessage, sender: CommandSender): Member {
         return if (raw is At) {
             checkArgument(sender is MemberCommandSender)
-            sender.group.members[raw.target]
+            val bot = sender.inferBotOrFail()
+            val group = sender.inferGroupOrFail()
+            if (raw.target == bot.id) {
+                return group.botAsMember
+            }
+            group[raw.target]
         } else {
             parse(raw.content, sender)
         }
@@ -247,10 +255,12 @@ internal interface InternalCommandArgumentParserExtensions<T : Any> : CommandArg
     fun Bot.findMemberOrFail(id: String): Friend =
         getFriendOrNull(id.parseToLongOrFail()) ?: illegalArgument("无法找到群员: $this")
 
-    fun Group.findMemberOrFail(idOrCard: String): Member =
-        idOrCard.toLongOrNull()?.let { getOrNull(it) }
+    fun Group.findMemberOrFail(idOrCard: String): Member {
+        if (idOrCard == "\$") return members.randomOrNull() ?: illegalArgument("当前语境下无法推断随机群员")
+        return idOrCard.toLongOrNull()?.let { getOrNull(it) }
             ?: fuzzySearchMember(idOrCard)
             ?: illegalArgument("无法找到目标群员 $idOrCard")
+    }
 
     fun CommandSender.inferBotOrFail(): Bot = (this as? BotAwareCommandSender)?.bot ?: illegalArgument("当前语境下无法推断目标群员")
 

backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/internal/command/internal.kt

@@ -14,6 +14,7 @@ import net.mamoe.mirai.console.command.description.CommandArgumentParserExceptio
 import net.mamoe.mirai.contact.Group
 import net.mamoe.mirai.contact.Member
 import net.mamoe.mirai.contact.nameCardOrNick
+import kotlin.math.max
 
 
 internal infix fun Array<String>.matchesBeginning(list: List<Any>): Boolean {
@@ -31,53 +32,39 @@ internal infix fun Array<out String>.intersectsIgnoringCase(other: Array<out Str
     return false
 }
 
-internal fun String.fuzzyCompare(target: String): Double {
-    var step = 0
+internal fun String.fuzzyMatchWith(target: String): Double {
     if (this == target) {
         return 1.0
     }
-    if (target.length > this.length) {
-        return 0.0
-    }
-    for (i in this.indices) {
-        if (target.length == i) {
-            step--
-        } else {
-            if (this[i] != target[i]) {
-                break
-            }
-            step++
+    var match = 0
+    for (i in 0..(max(this.lastIndex, target.lastIndex))) {
+        val t = target.getOrNull(match)
+        if (t == this.getOrNull(i) && t != null) {
+            match++
         }
     }
-
-    if (step == this.length - 1) {
-        return 1.0
-    }
-    return step.toDouble() / this.length
+    return match.toDouble() / (max(this.lastIndex, target.lastIndex) + 1)
 }
 
-/**
- * 模糊搜索一个List中index最接近target的东西
- */
 internal inline fun <T : Any> Collection<T>.fuzzySearch(
     target: String,
-    index: (T) -> String
+    crossinline index: (T) -> String
 ): T? {
-    var potential: T? = null
-    var rate = 0.0
-    this.forEach {
-        val thisIndex = index(it)
-        if (thisIndex == target) {
-            return it
-        }
-        with(thisIndex.fuzzyCompare(target)) {
-            if (this > rate) {
-                rate = this
-                potential = it
-            }
+    var maxElement: T? = null
+    var max = 0.0
+
+    for (t in this) {
+        val r = index(t).fuzzyMatchWith(target)
+        if (r > max) {
+            maxElement = t
+            max = r
         }
     }
-    return potential
+
+    if (max >= 0.7) {
+        return maxElement
+    }
+    return null
 }
 
 /**
@@ -93,7 +80,7 @@ internal inline fun <T : Any> Collection<T>.fuzzySearchOnly(
     var rate = 0.0
     var collide = 0
     this.forEach {
-        with(index(it).fuzzyCompare(target)) {
+        with(index(it).fuzzyMatchWith(target)) {
             if (this > rate) {
                 rate = this
                 potential = it