diff --git a/TODO b/TODO
index 155ed765..24fedd49 100644
--- a/TODO
+++ b/TODO
@@ -2,3 +2,7 @@
 为model.system添加缓存
 bug修复
 修复discussion前端权限节点显示异常
+web端运行脚本似乎异常
+讨论回复通知
+比赛举办者发布通知
+举报功能
diff --git a/hydro/entry/setup.ts b/hydro/entry/setup.ts
index 55a19cdd..7f341975 100644
--- a/hydro/entry/setup.ts
+++ b/hydro/entry/setup.ts
@@ -141,7 +141,7 @@ export function load() {
                 ),
                 db.collection('system').updateOne(
                     { _id: 'server.port' },
-                    { $set: { value: listenPort } },
+                    { $set: { value: parseInt(listenPort, 10) } },
                     { upsert: true },
                 ),
             ]);
diff --git a/hydro/handler/home.ts b/hydro/handler/home.ts
index 22a37b99..2be75628 100644
--- a/hydro/handler/home.ts
+++ b/hydro/handler/home.ts
@@ -336,6 +336,14 @@ class HomeMessagesHandler extends Handler {
         else throw new PermissionError();
         this.back();
     }
+
+    @param('messageId', Types.ObjectID)
+    async postRead(domainId: string, messageId: ObjectID) {
+        const msg = await message.get(messageId);
+        if ([msg.from, msg.to].includes(this.user._id)) await message.setFlag(messageId, message.FLAG_UNREAD);
+        else throw new PermissionError();
+        this.back();
+    }
 }
 
 class HomeMessagesConnectionHandler extends ConnectionHandler {
diff --git a/hydro/interface.ts b/hydro/interface.ts
index fd0ee80e..baa45895 100644
--- a/hydro/interface.ts
+++ b/hydro/interface.ts
@@ -69,6 +69,7 @@ export interface Pdoc {
     data?: ObjectID | string,
     hidden: boolean,
     config: string,
+    acMsg?: string,
 }
 
 export type Pdict = Dictionary<Pdoc>;
@@ -150,7 +151,7 @@ export interface Mdoc {
     from: number,
     to: number,
     content: string,
-    unread: boolean,
+    flag: number,
 }
 
 // Userfile
diff --git a/hydro/model/file.ts b/hydro/model/file.ts
index a781c541..694fd1de 100644
--- a/hydro/model/file.ts
+++ b/hydro/model/file.ts
@@ -135,6 +135,13 @@ export function url(arg0: any, name: any) {
     return __url(arg0, name);
 }
 
+export function ensureIndexes() {
+    return Promise.all([
+        collChunk.createIndex({ files_id: 1, n: 1 }, { unique: true }),
+        collFile.createIndex({ md5: 1 }),
+    ]);
+}
+
 global.Hydro.model.file = {
-    add, get, del, inc, dec, getMeta, getWithSecret, getMulti, getMetaDict, url,
+    add, get, del, inc, dec, getMeta, getWithSecret, getMulti, getMetaDict, url, ensureIndexes,
 };
diff --git a/hydro/model/message.ts b/hydro/model/message.ts
index c879ad6c..00c1fbc3 100644
--- a/hydro/model/message.ts
+++ b/hydro/model/message.ts
@@ -4,12 +4,15 @@ import * as db from '../service/db';
 
 const coll = db.collection('message');
 
-export async function send(from: number, to: number, content: string): Promise<Mdoc> {
+export const FLAG_UNREAD = 1;
+export const FLAG_NOTIFICATION = 2;
+
+export async function send(from: number, to: number, content: string, flag: number): Promise<Mdoc> {
     const res = await coll.insertOne({
-        from, to, content, unread: true,
+        from, to, content, flag: FLAG_UNREAD | flag,
     });
     return {
-        from, to, content, unread: true, _id: res.insertedId,
+        from, to, content, _id: res.insertedId, flag: FLAG_UNREAD | flag,
     };
 }
 
@@ -27,6 +30,15 @@ export async function getMany(query: any, sort: any, page: number, limit: number
         .toArray();
 }
 
+export async function setFlag(messageId: ObjectID, flag: number) {
+    const result = await coll.findOneAndUpdate(
+        { _id: messageId },
+        { $bit: { flag: { xor: flag } } },
+        { returnOriginal: false },
+    );
+    return result.value;
+}
+
 export async function del(_id: ObjectID) {
     return await coll.deleteOne({ _id });
 }
@@ -47,10 +59,14 @@ export function ensureIndexes() {
 }
 
 global.Hydro.model.message = {
+    FLAG_UNREAD,
+    FLAG_NOTIFICATION,
+
     count,
     get,
     getByUser,
     del,
+    setFlag,
     getMany,
     getMulti,
     send,
diff --git a/hydro/model/problem.ts b/hydro/model/problem.ts
index 1eef4b81..dd6d813f 100644
--- a/hydro/model/problem.ts
+++ b/hydro/model/problem.ts
@@ -22,6 +22,7 @@ export const pdocHidden: Pdoc = {
     data: null,
     hidden: true,
     config: '',
+    acMsg: '',
 };
 
 export async function add(
diff --git a/hydro/service/server.ts b/hydro/service/server.ts
index 58dfd2cf..875b2534 100644
--- a/hydro/service/server.ts
+++ b/hydro/service/server.ts
@@ -13,6 +13,7 @@ import Router from 'koa-router';
 import cache from 'koa-static-cache';
 import sockjs from 'sockjs';
 import serialize from 'serialize-javascript';
+import parse from 'yargs-parser';
 import { lrucache } from '../utils';
 import { User, DomainDoc } from '../interface';
 import {
@@ -31,8 +32,8 @@ import * as token from '../model/token';
 import * as opcount from '../model/opcount';
 import hash from '../lib/hash.hydro';
 
+const argv = parse(process.argv.slice(2));
 let enableLog = true;
-
 const app = new Koa();
 let server;
 const router = new Router();
@@ -760,8 +761,8 @@ export async function start() {
     } else enableLog = false;
     app.use(router.routes()).use(router.allowedMethods());
     Route('notfound_handler', '*', Handler);
-    server.listen(port);
-    console.log('Server listening at: %s', port);
+    server.listen(argv.port || port);
+    console.log('Server listening at: %s', argv.port || port);
 }
 
 global.Hydro.service.server = {
diff --git a/templates/partials/problem_sidebar_normal.html b/templates/partials/problem_sidebar_normal.html
index 0c4656a7..7b5a2dc0 100644
--- a/templates/partials/problem_sidebar_normal.html
+++ b/templates/partials/problem_sidebar_normal.html
@@ -97,6 +97,10 @@
       {% else %}
         {{ _('(None)') }}
       {% endif %}
+      {% if pdoc['acMsg'] and pdoc['psdoc']['status'] == STATUS.STATUS_ACCEPTED %}
+        <dt>{{ _('AC Message') }}</dt>
+        <dd>{{ pdoc['acMsg'] }}</dd>
+      {% endif %}
       </dd>
     {% endif %}
     {% endif %}