From 2abededab6862b7d9b5ab8282fab57a7695260b3 Mon Sep 17 00:00:00 2001
From: Shigma <shigma10826@gmail.com>
Date: Tue, 7 May 2024 00:50:51 +0800
Subject: [PATCH] feat(database): sequence tracing

---
 packages/database/src/channel.ts | 21 +++++++++++----------
 packages/database/src/index.ts   | 14 +++++++++++++-
 2 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/packages/database/src/channel.ts b/packages/database/src/channel.ts
index c4c9c397..d7edefd1 100644
--- a/packages/database/src/channel.ts
+++ b/packages/database/src/channel.ts
@@ -78,12 +78,10 @@ export class SyncChannel {
   }
 
   async queue(session: Session) {
-    const message = Message.from(session.event.message!, session.platform)
+    const prev = this._hasLatest ? this._spans[0] : undefined
+    const message = Message.from(session.event.message!, session.platform, 'after', prev?.front[0])
     const span = this.insert([message], 0)
-    if (this._hasLatest) {
-      span.prev = this._spans[1]
-      span.prev.next = span
-    }
+    span.link('prev', prev)
     this._hasLatest = true
     span.flush()
   }
@@ -104,7 +102,7 @@ export class SyncChannel {
     return [...before, message, ...after]
   }
 
-  private async locate(id: string, direction: Universal.Direction, limit: number): Promise<[Span, MessageLike, boolean?]> {
+  private async locate(id: string, direction: Universal.Direction, limit?: number): Promise<[Span, MessageLike, boolean?]> {
     // condition 1: message in memory
     for (const span of this._spans) {
       const message = span.data?.find(message => message.id === id)
@@ -145,14 +143,15 @@ export class SyncChannel {
     for (let i = index - 1; i >= 0; i--) {
       prev = this._spans.find(span => span.front[1] === result.data[i].id)
       if (prev) break
-      data.unshift(Message.from(result.data[i], this.bot.platform))
+      // @ts-ignore
+      data.unshift(Message.from(result.data[i], this.bot.platform, 'before', data[0]?.sid))
     }
 
     let next: Span | undefined
     for (let i = index + 1; i < result.data.length; i++) {
       next = this._spans.find(span => span.back[1] === result.data[i].id)
       if (next) break
-      data.push(Message.from(result.data[i], this.bot.platform))
+      data.push(Message.from(result.data[i], this.bot.platform, 'after', data[data.length - 1]?.sid))
     }
 
     if (data.length) {
@@ -230,13 +229,15 @@ export class SyncChannel {
       span[dir.next] ??= await (span[`${dir.next}Task`] ??= (async (prev: Span) => {
         const data: Message[] = []
         const result = await this.bot.getMessageList(this.channelId, prev[dir.front][1], direction, limit - buffer.length, dir.asc)
-        let next: Span | undefined
+        let next: Span | undefined, last: Message | undefined
         for (const item of result.data) {
           next = this._spans.find(span => span[dir.back][1] === item.id)
           if (next) break
-          data.push(Message.from(item, this.bot.platform))
+          last = Message.from(item, this.bot.platform, direction, last?.sid)
+          data[dir.push](last)
         }
         if (data.length) {
+          // TODO sync new span
           const span = this.insert(data)
           span.link(dir.prev, prev)
           span.link(dir.next, next)
diff --git a/packages/database/src/index.ts b/packages/database/src/index.ts
index 4dfa858a..d3e7c8e2 100644
--- a/packages/database/src/index.ts
+++ b/packages/database/src/index.ts
@@ -44,9 +44,21 @@ export interface Message extends Universal.Message {
 }
 
 export namespace Message {
-  export const from = (message: Universal.Message, platform: string) => ({
+  export type Ref = ['before' | 'after', bigint]
+
+  function sequence(ts: bigint, dir?: 'before' | 'after', ref?: bigint) {
+    if (!dir || !ref) return (ts << 12n) + 0x800n
+    if (ts === ref >> 12n) {
+      return ref + (dir === 'before' ? -1n : 1n)
+    } else {
+      return (ts << 12n) + (dir === 'before' ? 0xfffn : 0n)
+    }
+  }
+
+  export const from = (message: Universal.Message, platform: string, dir?: 'before' | 'after', ref?: bigint) => ({
     platform,
     id: message.id,
+    sid: sequence(BigInt(message.timestamp!), dir, ref),
     content: message.content,
     timestamp: message.timestamp,
     channel: { id: message.channel?.id },