refactor: Update Prisma schema to include UserMessage, Class, Room, and RoomMessage models

prisma/schema.prisma

@@ -1,21 +1,64 @@
-// This is your Prisma schema file,
-// learn more about it in the docs: https://pris.ly/d/prisma-schema
-
-// Looking for ways to speed up your queries, or scale easily with your serverless or edge functions?
-// Try Prisma Accelerate: https://pris.ly/cli/accelerate-init
-
 generator client {
     provider = "prisma-client-js"
 }
 
 datasource db {
-    provider = "sqlite"
+    provider = "mysql"
     url      = env("DATABASE_URL")
 }
 
 model User {
     id       String  @id @default(cuid())
     username String?
-    isAdmin  Boolean @default(false)
+    role     Role    @default(STUDENT)
-    password String?
+
+    Class            Class[]
+    SentMessages     UserMessage[] @relation("SentMessages")
+    ReceivedMessages UserMessage[] @relation("ReceivedMessages")
+}
+
+model UserMessage {
+    id      Int    @id @default(autoincrement())
+    content String
+
+    sender         User   @relation(fields: [sender_user_Id], references: [id], name: "SentMessages")
+    sender_user_Id String
+
+    receiver         User   @relation(fields: [receiver_user_Id], references: [id], name: "ReceivedMessages")
+    receiver_user_Id String
+}
+
+model Class {
+    id   String @id @default(cuid())
+    name String
+
+    ClassRoom Room[]
+    students  User[]
+}
+
+model Room {
+    id        String         @id @default(cuid())
+    name      String
+    class     Class[]
+    Messages  RoomMessage[]
+    Documents RoomDocument[]
+}
+
+model RoomMessage {
+    id      Int    @id @default(autoincrement())
+    content String
+    Room    Room   @relation(fields: [roomId], references: [id])
+    roomId  String
+}
+
+model RoomDocument {
+    id      Int    @id @default(autoincrement())
+    content String
+    Room    Room   @relation(fields: [roomId], references: [id])
+    roomId  String
+}
+
+enum Role {
+    STUDENT
+    TEACHER
 }