diff --git a/packages/geoip/lib.ts b/packages/geoip/lib.ts
index ca325cc4c..0ceecc87a 100644
--- a/packages/geoip/lib.ts
+++ b/packages/geoip/lib.ts
@@ -14,7 +14,7 @@ export interface Result {
     display: string
 }
 
-export function lookup(ip: string, locale: string): any {
+export function lookup(ip: string, locale: string) {
     const res: any = reader.get(ip);
     if (!res) return {};
     const ret: Result = { display: '' };
diff --git a/packages/geoip/package.json b/packages/geoip/package.json
index dfd5d11e8..f33b6c06f 100644
--- a/packages/geoip/package.json
+++ b/packages/geoip/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@hydrooj/geoip",
-    "version": "1.1.11",
+    "version": "1.1.12",
     "main": "package.json",
     "repository": "git@github.com:hydro-dev/Hydro.git",
     "author": "undefined <masnn0@outlook.com>",
diff --git a/packages/hydrooj/package.json b/packages/hydrooj/package.json
index c7a3f93d9..949d886f8 100644
--- a/packages/hydrooj/package.json
+++ b/packages/hydrooj/package.json
@@ -1,6 +1,6 @@
 {
     "name": "hydrooj",
-    "version": "2.12.26",
+    "version": "2.12.27",
     "bin": "bin/hydrooj.js",
     "main": "dist/loader.js",
     "typings": "dist/loader.d.ts",
diff --git a/packages/hydrooj/src/check.ts b/packages/hydrooj/src/check.ts
index 343f2167e..c2e62047d 100644
--- a/packages/hydrooj/src/check.ts
+++ b/packages/hydrooj/src/check.ts
@@ -43,7 +43,7 @@ const checks: Dictionary<CheckItem> = {
     },
 };
 
-export async function start(ctx, log, warn, error, cb) {
+export async function start(ctx, log, warn, error, cb: (id: string) => any) {
     const id = String.random(6);
     cb(id);
     for (const name in checks) {
diff --git a/packages/hydrooj/src/handler/domain.ts b/packages/hydrooj/src/handler/domain.ts
index 59602f9ba..412e2b41c 100644
--- a/packages/hydrooj/src/handler/domain.ts
+++ b/packages/hydrooj/src/handler/domain.ts
@@ -14,6 +14,7 @@ import paginate from '../lib/paginate';
 import {
     Route, Handler, Types, param,
 } from '../service/server';
+import { DomainDoc } from '../interface';
 
 class DomainRankHandler extends Handler {
     @param('page', Types.PositiveInt, true)
@@ -40,7 +41,7 @@ class DomainRankHandler extends Handler {
 }
 
 class ManageHandler extends Handler {
-    domain: any;
+    domain: DomainDoc;
 
     async prepare({ domainId }) {
         this.checkPerm(PERM.PERM_EDIT_DOMAIN);
diff --git a/packages/hydrooj/src/handler/manage.ts b/packages/hydrooj/src/handler/manage.ts
index 388a0c7e5..5edf4f3ca 100644
--- a/packages/hydrooj/src/handler/manage.ts
+++ b/packages/hydrooj/src/handler/manage.ts
@@ -51,7 +51,7 @@ class SystemMainHandler extends SystemHandler {
 }
 
 class SystemCheckConnHandler extends ConnectionHandler {
-    id: any;
+    id: string;
 
     async prepare() {
         this.checkPriv(PRIV.PRIV_EDIT_SYSTEM);
diff --git a/packages/hydrooj/src/handler/training.ts b/packages/hydrooj/src/handler/training.ts
index d2320366f..a18c01560 100644
--- a/packages/hydrooj/src/handler/training.ts
+++ b/packages/hydrooj/src/handler/training.ts
@@ -102,8 +102,8 @@ class TrainingDetailHandler extends Handler {
             problem.getList(domainId, pids, this.user.hasPerm(PERM.PERM_VIEW_PROBLEM_HIDDEN)),
         ]);
         const psdict = await problem.getListStatus(domainId, this.user._id, pids);
-        const donePids = new Set();
-        const progPids = new Set();
+        const donePids = new Set<number>();
+        const progPids = new Set<number>();
         for (const pid in psdict) {
             const psdoc = psdict[pid];
             if (psdoc.status) {
@@ -114,7 +114,7 @@ class TrainingDetailHandler extends Handler {
         }
         const nsdict = {};
         const ndict = {};
-        const doneNids = new Set();
+        const doneNids = new Set<number>();
         for (const node of tdoc.dag) {
             ndict[node._id] = node;
             const totalCount = node.pids.length;
@@ -174,13 +174,9 @@ class TrainingCreateHandler extends Handler {
         _dag: string, description: string,
     ) {
         const dag = await _parseDagJson(domainId, _dag);
-        const pids = training.getPids({ dag });
+        const pids = training.getPids(dag);
         assert(pids.length, new ValidationError('dag'));
-        const pdocs = await problem.getMulti(domainId, {
-            // TODO
-            // @ts-ignore
-            $or: [{ docId: { $in: pids } }, { pid: { $in: pids } }],
-        }).sort('_id', 1).toArray();
+        const pdocs = await problem.getMulti(domainId, { docId: { $in: pids } }).sort('_id', 1).toArray();
         const existPids = pdocs.map((pdoc) => pdoc.docId);
         const existPnames = pdocs.map((pdoc) => pdoc.pid);
         if (pids.length !== existPids.length) {
@@ -235,7 +231,7 @@ class TrainingEditHandler extends Handler {
         _dag: string, description: string,
     ) {
         const dag = await _parseDagJson(domainId, _dag);
-        const pids = training.getPids({ dag });
+        const pids = training.getPids(dag);
         assert(pids.length, new ValidationError('dag'));
         const pdocs = await problem.getMulti(domainId, {
             $or: [
diff --git a/packages/hydrooj/src/interface.ts b/packages/hydrooj/src/interface.ts
index 39241e121..928ec384e 100644
--- a/packages/hydrooj/src/interface.ts
+++ b/packages/hydrooj/src/interface.ts
@@ -31,7 +31,7 @@ export interface Udoc extends Dictionary<any> {
 }
 
 export interface User extends Dictionary<any> {
-    udoc: () => any,
+    udoc: () => Udoc,
     dudoc: () => any,
     _id: number,
     mail: string,
@@ -211,6 +211,13 @@ export interface ScoreboardNode {
 
 export type PenaltyRules = Dictionary<number>;
 
+export interface TrainingNode {
+    _id: number,
+    title: string,
+    requireNids: number[],
+    pids: number[],
+}
+
 export interface Tdoc {
     _id: ObjectID,
     domainId: string,
@@ -230,7 +237,13 @@ export interface Tdoc {
     penaltyRules?: PenaltyRules,
 
     // For training
-    dag: any
+    description?: string,
+    dag?: TrainingNode[],
+}
+
+export interface TrainingDoc extends Tdoc {
+    description: string,
+    dag: TrainingNode[],
 }
 
 export interface DomainDoc extends Dictionary<any> {
@@ -365,7 +378,7 @@ export interface JudgeResultBody {
     stderr?: string,
 }
 
-export type PathComponent = [string, string, any?, boolean?];
+export type PathComponent = [string, string, Dictionary<any>?, boolean?];
 
 export interface Model {
     blacklist: typeof import('./model/blacklist'),
diff --git a/packages/hydrooj/src/model/builtin.ts b/packages/hydrooj/src/model/builtin.ts
index 78d703aba..a1c1b8fd4 100644
--- a/packages/hydrooj/src/model/builtin.ts
+++ b/packages/hydrooj/src/model/builtin.ts
@@ -533,6 +533,11 @@ export const LANG_HIGHLIGHT_ID = {
     rb: 'ruby',
 };
 
+export function registerLanguage(id: string, display: string, highlight: string) {
+    LANG_TEXTS[id] = display;
+    LANG_HIGHLIGHT_ID[id] = highlight;
+}
+
 export const STATUS = {
     STATUS_WAITING: 0,
     STATUS_ACCEPTED: 1,
@@ -618,6 +623,7 @@ export const CONSTANT = {
 
 global.Hydro.model.builtin = {
     Permission,
+    registerLanguage,
     PERM,
     PERMS,
     PERMS_BY_FAMILY,
diff --git a/packages/hydrooj/src/model/discussion.ts b/packages/hydrooj/src/model/discussion.ts
index ce6423894..2d93a7df6 100644
--- a/packages/hydrooj/src/model/discussion.ts
+++ b/packages/hydrooj/src/model/discussion.ts
@@ -183,7 +183,7 @@ export async function getVnode(domainId: string, type: number, id: string) {
         };
     }
     if (type === document.TYPE_TRAINING) {
-        const tdoc = await training.get(domainId, id);
+        const tdoc = await training.get(domainId, new ObjectID(id));
         return { ...tdoc, type, id };
     }
     if (type === document.TYPE_HOMEWORK) {
diff --git a/packages/hydrooj/src/model/training.ts b/packages/hydrooj/src/model/training.ts
index 64f3b8125..c01244576 100644
--- a/packages/hydrooj/src/model/training.ts
+++ b/packages/hydrooj/src/model/training.ts
@@ -1,6 +1,8 @@
-import { ObjectID } from 'mongodb';
+import { FilterQuery, ObjectID } from 'mongodb';
+import { flatten } from 'lodash';
 import * as document from './document';
 import { TrainingNotFoundError, TrainingAlreadyEnrollError } from '../error';
+import { TrainingDoc, TrainingNode } from '../interface';
 
 export function getStatus(domainId: string, tid: ObjectID, uid: number) {
     return document.getStatus(domainId, document.TYPE_TRAINING, tid, uid);
@@ -34,7 +36,7 @@ export function setStatus(domainId: string, tid: ObjectID, uid: number, $set: an
 
 export function add(
     domainId: string, title: string, content: string,
-    owner: number, dag = [], description = '',
+    owner: number, dag: TrainingNode[] = [], description = '',
 ) {
     return document.add(domainId, content, owner, document.TYPE_TRAINING, null, null, null, {
         dag,
@@ -44,24 +46,20 @@ export function add(
     });
 }
 
-export function edit(domainId: string, tid: ObjectID, $set) {
+export function edit(domainId: string, tid: ObjectID, $set: Partial<TrainingDoc>) {
     return document.set(domainId, document.TYPE_TRAINING, tid, $set);
 }
 
-export function getPids(tdoc): number[] {
-    const pids: Set<number> = new Set();
-    for (const node of tdoc.dag) {
-        for (const pid of node.pids) pids.add(pid);
-    }
-    return Array.from(pids);
+export function getPids(dag: TrainingNode[]) {
+    return Array.from(new Set(flatten(dag.map((node) => node.pids))));
 }
 
-export function isDone(node, doneNids, donePids) {
+export function isDone(node: TrainingNode, doneNids: Set<number> | number[], donePids: Set<number> | number[]) {
     return (Set.isSuperset(new Set(doneNids), new Set(node.requireNids))
         && Set.isSuperset(new Set(donePids), new Set(node.pids)));
 }
 
-export function isProgress(node, doneNids, donePids, progPids) {
+export function isProgress(node: TrainingNode, doneNids: Set<number> | number[], donePids: Set<number> | number[], progPids: Set<number> | number[]) {
     return (Set.isSuperset(new Set(doneNids), new Set(node.requireNids))
         && !Set.isSuperset(new Set(donePids), new Set(node.pids))
         && Set.intersection(
@@ -70,7 +68,7 @@ export function isProgress(node, doneNids, donePids, progPids) {
         ).size);
 }
 
-export function isOpen(node, doneNids, donePids, progPids) {
+export function isOpen(node: TrainingNode, doneNids: Set<number> | number[], donePids: Set<number> | number[], progPids: Set<number> | number[]) {
     return (Set.isSuperset(new Set(doneNids), new Set(node.requireNids))
         && !Set.isSuperset(new Set(donePids), new Set(node.pids))
         && !Set.intersection(
@@ -79,13 +77,14 @@ export function isOpen(node, doneNids, donePids, progPids) {
         ).size);
 }
 
-export const isInvalid = (node, doneNids) =>
+export const isInvalid = (node: TrainingNode, doneNids: Set<number> | number[]) =>
     !Set.isSuperset(new Set(doneNids), new Set(node.requireNids));
 
-export const count = (domainId: string, query: any) =>
-    document.count(domainId, document.TYPE_TRAINING, query);
+export async function count(domainId: string, query: FilterQuery<TrainingDoc>) {
+    return await document.count(domainId, document.TYPE_TRAINING, query);
+}
 
-export async function get(domainId, tid) {
+export async function get(domainId: string, tid: ObjectID) {
     const tdoc = await document.get(domainId, document.TYPE_TRAINING, tid);
     if (!tdoc) throw new TrainingNotFoundError(tid);
     for (const i in tdoc.dag) {
@@ -107,7 +106,7 @@ export async function getList(domainId: string, tids: ObjectID[]) {
     return r;
 }
 
-export const getMulti = (domainId: string, query: any = {}) =>
+export const getMulti = (domainId: string, query: FilterQuery<TrainingDoc> = {}) =>
     document.getMulti(domainId, document.TYPE_TRAINING, query).sort('_id', 1);
 
 global.Hydro.model.training = {