feat: scaffold center and guild backend NestJS skeletons

Fabric.Backend.Guild/src/messaging/messaging.controller.ts

@@ -0,0 +1,62 @@
+import { Body, Controller, Delete, Get, Param, Patch, Post, Query } from '@nestjs/common';
+
+type Message = {
+  messageId: string;
+  seq: number;
+  content: string;
+};
+
+@Controller('channels/:id/messages')
+export class MessagingController {
+  private seqByChannel = new Map<string, number>();
+  private messagesByChannel = new Map<string, Message[]>();
+
+  @Post()
+  create(@Param('id') channelId: string, @Body() body: { content?: string; messageId?: string }) {
+    const next = (this.seqByChannel.get(channelId) ?? 0) + 1;
+    this.seqByChannel.set(channelId, next);
+
+    const message: Message = {
+      messageId: body.messageId ?? `m-${channelId}-${next}`,
+      seq: next,
+      content: body.content ?? '',
+    };
+
+    const arr = this.messagesByChannel.get(channelId) ?? [];
+    arr.push(message);
+    this.messagesByChannel.set(channelId, arr);
+
+    return message;
+  }
+
+  @Patch(':messageId')
+  edit(@Param('id') channelId: string, @Param('messageId') messageId: string, @Body() body: { content?: string }) {
+    const arr = this.messagesByChannel.get(channelId) ?? [];
+    const item = arr.find((m) => m.messageId === messageId);
+    if (!item) return { status: 'not_found' };
+    item.content = body.content ?? item.content;
+    return item;
+  }
+
+  @Delete(':messageId')
+  remove(@Param('id') channelId: string, @Param('messageId') messageId: string) {
+    const arr = this.messagesByChannel.get(channelId) ?? [];
+    const next = arr.filter((m) => m.messageId !== messageId);
+    this.messagesByChannel.set(channelId, next);
+    return { status: 'deleted', messageId };
+  }
+
+  @Get()
+  listBySeq(
+    @Param('id') channelId: string,
+    @Query('seq_from') seqFrom?: string,
+    @Query('seq_to') seqTo?: string,
+  ) {
+    const from = seqFrom ? Number(seqFrom) : 1;
+    const to = seqTo ? Number(seqTo) : Number.MAX_SAFE_INTEGER;
+    const arr = this.messagesByChannel.get(channelId) ?? [];
+    return {
+      items: arr.filter((m) => m.seq >= from && m.seq <= to),
+    };
+  }
+}