// 班级小助手 - 数据模型
//
// 设计说明：
// 1) 本 schema 使用 sqlite provider（本地 MVP / 离线开发）。
//    字段全部使用 String / Int / Float / Boolean / DateTime 等跨库通用类型，
//    不使用 Prisma enum 与 @db.* 原生类型，因此可平移到 MySQL。
//    MySQL 版本见同目录 schema.mysql.prisma，切换步骤见 docs/mysql.md。
// 2) 角色与优先级用 String 存储（'ADMIN' | 'TEACHER' | 'STUDENT'、
//    'LOW' | 'NORMAL' | 'HIGH' | 'URGENT'），在 API 层用 zod 校验，
//    这样 SQLite / MySQL 行为完全一致。
// 3) 所有主键使用 cuid 字符串，便于多端离线生成与合并。

generator client {
  provider = "prisma-client"
  output   = "../src/generated/prisma"
}

datasource db {
  provider = "sqlite"
}

/// 用户：教师 / 管理员 / 学生统一存储
model User {
  id           String   @id @default(cuid())
  username     String   @unique
  passwordHash String
  name         String
  role         String   @default("STUDENT")
  classId      String?
  createdAt    DateTime @default(now())
  updatedAt    DateTime @updatedAt

  // 学生的主班级（一个学生属于一个主班级）
  class             Class?             @relation("ClassStudents", fields: [classId], references: [id], onDelete: SetNull)
  // 教师创建（负责）的班级
  ownedClasses      Class[]            @relation("ClassOwner")
  // 教师被分配协作的班级
  classAssignments  ClassTeacher[]
  courses           Course[]
  homeworkStatuses  HomeworkStatus[]
  notificationReads NotificationRead[]
  grades            Grade[]
  enrollments       Enrollment[]
  createdHomeworks  Homework[]         @relation("HomeworkCreator")
  createdNotices    Notification[]     @relation("NotificationCreator")

  @@index([classId])
  @@index([role])
}

/// 班级
model Class {
  id        String   @id @default(cuid())
  name      String
  grade     String
  teacherId String
  /// 班级码：学生端「班级账号」登录用（唯一，字母数字，4~16 位，存大写）
  code      String   @unique
  /// 班级密码（bcrypt 哈希）；null = 尚未设置，此时禁止班级账号登录
  passwordHash String?
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt

  teacher       User             @relation("ClassOwner", fields: [teacherId], references: [id], onDelete: Cascade)
  students      User[]           @relation("ClassStudents")
  teachers      ClassTeacher[]
  courses       Course[]
  schedules     Schedule[]
  homeworks     Homework[]
  notifications Notification[]
  grades        Grade[]
  enrollments   Enrollment[]
  timeLayouts   TimeLayout[]

  @@index([teacherId])
}

/// 教师-班级 分配关系（一个教师可管理多个班级）
model ClassTeacher {
  id        String   @id @default(cuid())
  classId   String
  teacherId String
  createdAt DateTime @default(now())

  class   Class @relation(fields: [classId], references: [id], onDelete: Cascade)
  teacher User  @relation(fields: [teacherId], references: [id], onDelete: Cascade)

  @@unique([classId, teacherId])
  @@index([teacherId])
}

/// 学生-班级 选课/归属记录（与 User.classId 保持同步，支持未来多班）
model Enrollment {
  id        String   @id @default(cuid())
  userId    String
  classId   String
  createdAt DateTime @default(now())

  user  User  @relation(fields: [userId], references: [id], onDelete: Cascade)
  class Class @relation(fields: [classId], references: [id], onDelete: Cascade)

  @@unique([userId, classId])
  @@index([classId])
}

/// 课程
model Course {
  id        String   @id @default(cuid())
  name      String
  teacherId String
  classId   String
  createdAt DateTime @default(now())

  teacher   User       @relation(fields: [teacherId], references: [id], onDelete: Cascade)
  class     Class      @relation(fields: [classId], references: [id], onDelete: Cascade)
  schedules Schedule[]
  homeworks Homework[]
  grades    Grade[]

  @@unique([classId, name])
  @@index([classId])
}

/// 课表条目
model Schedule {
  id        String   @id @default(cuid())
  classId   String
  courseId  String
  /// 1=周一 ... 7=周日
  dayOfWeek Int
  /// HH:mm
  startTime String
  /// HH:mm
  endTime   String
  location  String?
  /// 学期起始周次（含）
  weekStart Int      @default(1)
  /// 学期结束周次（含）
  weekEnd   Int      @default(20)
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt

  class  Class  @relation(fields: [classId], references: [id], onDelete: Cascade)
  course Course @relation(fields: [courseId], references: [id], onDelete: Cascade)

  @@index([classId, dayOfWeek])
  @@index([courseId])
}

/// 作业
model Homework {
  id            String    @id @default(cuid())
  classId       String
  courseId      String?
  title         String
  content       String
  attachmentUrl String?
  /// 遗留字段：作业"截止时间"功能已下线（UI/接口均不再读写）。
  /// 保留列以免对已安装的库做破坏性迁移；新库该列恒为 null。
  dueAt         DateTime?
  createdBy     String
  createdAt     DateTime  @default(now())
  updatedAt     DateTime  @updatedAt

  class    Class            @relation(fields: [classId], references: [id], onDelete: Cascade)
  course   Course?          @relation(fields: [courseId], references: [id], onDelete: SetNull)
  creator  User             @relation("HomeworkCreator", fields: [createdBy], references: [id], onDelete: Cascade)
  statuses HomeworkStatus[]

  @@index([classId, createdAt])
  @@index([courseId])
  @@index([dueAt])
}

/// 学生作业完成状态
model HomeworkStatus {
  id         String   @id @default(cuid())
  homeworkId String
  userId     String
  completed  Boolean  @default(false)
  updatedAt  DateTime @updatedAt

  homework Homework @relation(fields: [homeworkId], references: [id], onDelete: Cascade)
  user     User     @relation(fields: [userId], references: [id], onDelete: Cascade)

  @@unique([homeworkId, userId])
  @@index([userId])
}

/// 通知
model Notification {
  id        String   @id @default(cuid())
  classId   String
  title     String
  content   String
  priority  String   @default("NORMAL")
  createdBy String
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt

  class   Class              @relation(fields: [classId], references: [id], onDelete: Cascade)
  creator User               @relation("NotificationCreator", fields: [createdBy], references: [id], onDelete: Cascade)
  reads   NotificationRead[]

  @@index([classId, createdAt])
}

/// 通知已读记录
model NotificationRead {
  id             String   @id @default(cuid())
  notificationId String
  userId         String
  readAt         DateTime @default(now())

  notification Notification @relation(fields: [notificationId], references: [id], onDelete: Cascade)
  user         User         @relation(fields: [userId], references: [id], onDelete: Cascade)

  @@unique([notificationId, userId])
  @@index([userId])
}


/// 课表时间配置（ClassIsland 同款 JSON 导入后的节次时间表）
model TimeLayout {
  id        String   @id @default(cuid())
  classId   String
  name      String
  /// 来源：classisland | manual
  source    String   @default("classisland")
  /// 节次数组（JSON 字符串）：[{ index, name, startTime, endTime, type, skipped }]
  items     String
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt

  class Class @relation(fields: [classId], references: [id], onDelete: Cascade)

  @@index([classId])
}

/// 成绩
model Grade {
  id          String   @id @default(cuid())
  classId     String
  courseId    String?
  userId      String
  examName    String
  score       Float
  totalScore  Float    @default(100)
  publishedAt DateTime @default(now())
  createdAt   DateTime @default(now())
  updatedAt   DateTime @updatedAt

  class   Class   @relation(fields: [classId], references: [id], onDelete: Cascade)
  course  Course? @relation(fields: [courseId], references: [id], onDelete: SetNull)
  student User    @relation(fields: [userId], references: [id], onDelete: Cascade)

  @@index([userId, publishedAt])
  @@index([classId, examName])
  @@index([courseId])
}