// This is your Prisma schema file,
// learn more about it in the docs: https://pris.ly/d/prisma-schema

generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider = "sqlite"
  url      = "file:./dev.db"
}

model Course {
  id            String    @id @default(uuid())
  title         String
  description   String
  category      String    // ML_BASICS, DEEP_LEARNING, NLP, LLM, AI_TOOLS
  difficulty    String    // BEGINNER, INTERMEDIATE, ADVANCED
  estimatedHours Int
  createdAt     DateTime  @default(now())
  updatedAt     DateTime  @updatedAt
  chapters      Chapter[]
  pathItems     PathItem[]
}

model Chapter {
  id          String   @id @default(uuid())
  courseId    String
  title       String
  order       Int
  content     String   // Markdown content
  createdAt   DateTime @default(now())
  updatedAt   DateTime @updatedAt
  course      Course   @relation(fields: [courseId], references: [id], onDelete: Cascade)
  pathItems   PathItem[]
}

model LearningPath {
  id            String     @id @default(uuid())
  name          String
  description   String
  targetAudience String
  createdAt     DateTime   @default(now())
  updatedAt     DateTime   @updatedAt
  pathItems     PathItem[]
}

model PathItem {
  id          String        @id @default(uuid())
  pathId      String
  courseId    String
  chapterId   String?
  order       Int
  type        String        // 'course' or 'chapter'
  createdAt   DateTime      @default(now())
  updatedAt   DateTime      @updatedAt
  path        LearningPath  @relation(fields: [pathId], references: [id], onDelete: Cascade)
  course      Course        @relation(fields: [courseId], references: [id], onDelete: Cascade)
  chapter     Chapter?      @relation(fields: [chapterId], references: [id], onDelete: Cascade)
}

model UserProgress {
  id          String   @id @default(uuid())
  userId      String   @default("default") // MVP阶段使用默认用户
  courseId    String
  chapterId  String?
  completed  Boolean  @default(false)
  lastAccessed DateTime @default(now())
  createdAt   DateTime @default(now())
  updatedAt   DateTime @updatedAt
  
  @@unique([userId, courseId, chapterId])
}