import "dotenv/config";
import { db } from "../src/shared/db";
import { 
  users, roles, usersToRoles, 
  questions, knowledgePoints, questionsToKnowledgePoints,
  exams, examQuestions, examSubmissions, submissionAnswers,
  textbooks, chapters
} from "../src/shared/db/schema";
import { createId } from "@paralleldrive/cuid2";
import { faker } from "@faker-js/faker";
import { sql } from "drizzle-orm";

/**
 * Enterprise-Grade Seed Script for Next_Edu
 * 
 * Scenarios Covered:
 * 1. IAM: RBAC with multiple roles (Teacher & Grade Head).
 * 2. Knowledge Graph: Nested Knowledge Points (Math -> Algebra -> Linear Equations).
 * 3. Question Bank: Rich Text Content & Nested Questions (Reading Comprehension).
 * 4. Exams: JSON Structure for Sectioning.
 */

async function seed() {
  console.log("🌱 Starting Database Seed...");
  const start = performance.now();

  // --- 0. Cleanup (Optional: Truncate tables for fresh start) ---
  // Note: Order matters due to foreign keys if checks are enabled.
  // Ideally, use: SET FOREIGN_KEY_CHECKS = 0;
  try {
    await db.execute(sql`SET FOREIGN_KEY_CHECKS = 0;`);
    const tables = [
      "submission_answers", "exam_submissions", "exam_questions", "exams",
      "questions_to_knowledge_points", "questions", "knowledge_points",
      "chapters", "textbooks",
      "users_to_roles", "roles", "users", "accounts", "sessions"
    ];
    for (const table of tables) {
      await db.execute(sql.raw(`TRUNCATE TABLE \`${table}\`;`));
    }
    await db.execute(sql`SET FOREIGN_KEY_CHECKS = 1;`);
    console.log("🧹 Cleaned up existing data.");
  } catch (e) {
    console.warn("⚠️ Cleanup warning (might be fresh DB):", e);
  }

  // --- 1. IAM & Roles ---
  console.log("👤 Seeding IAM...");
  
  // Roles
  const roleMap = {
    admin: "role_admin",
    teacher: "role_teacher",
    student: "role_student",
    grade_head: "role_grade_head"
  };

  await db.insert(roles).values([
    { id: roleMap.admin, name: "admin", description: "System Administrator" },
    { id: roleMap.teacher, name: "teacher", description: "Academic Instructor" },
    { id: roleMap.student, name: "student", description: "Learner" },
    { id: roleMap.grade_head, name: "grade_head", description: "Head of Grade Year" }
  ]);

  // Users
  const usersData = [
    {
      id: "user_admin",
      name: "Admin User",
      email: "admin@next-edu.com",
      role: "admin", // Legacy field
      image: "https://api.dicebear.com/7.x/avataaars/svg?seed=Admin"
    },
    {
      id: "user_teacher_math",
      name: "Mr. Math",
      email: "math@next-edu.com",
      role: "teacher",
      image: "https://api.dicebear.com/7.x/avataaars/svg?seed=Math"
    },
    {
      id: "user_student_1",
      name: "Alice Student",
      email: "alice@next-edu.com",
      role: "student",
      image: "https://api.dicebear.com/7.x/avataaars/svg?seed=Alice"
    }
  ];

  await db.insert(users).values(usersData);

  // Assign Roles (RBAC)
  await db.insert(usersToRoles).values([
    { userId: "user_admin", roleId: roleMap.admin },
    { userId: "user_teacher_math", roleId: roleMap.teacher },
    // Math teacher is also a Grade Head
    { userId: "user_teacher_math", roleId: roleMap.grade_head },
    { userId: "user_student_1", roleId: roleMap.student },
  ]);

  // --- 2. Knowledge Graph (Tree) ---
  console.log("🧠 Seeding Knowledge Graph...");
  
  const kpMathId = createId();
  const kpAlgebraId = createId();
  const kpLinearId = createId();

  await db.insert(knowledgePoints).values([
    { id: kpMathId, name: "Mathematics", level: 0 },
    { id: kpAlgebraId, name: "Algebra", parentId: kpMathId, level: 1 },
    { id: kpLinearId, name: "Linear Equations", parentId: kpAlgebraId, level: 2 },
  ]);

  // --- 3. Question Bank (Rich Content) ---
  console.log("📚 Seeding Question Bank...");

  // 3.1 Simple Single Choice
  const qSimpleId = createId();
  await db.insert(questions).values({
    id: qSimpleId,
    authorId: "user_teacher_math",
    type: "single_choice",
    difficulty: 1,
    content: {
      text: "What is 2 + 2?",
      options: [
        { id: "A", text: "3", isCorrect: false },
        { id: "B", text: "4", isCorrect: true },
        { id: "C", text: "5", isCorrect: false }
      ]
    }
  });

  // Link to KP
  await db.insert(questionsToKnowledgePoints).values({
    questionId: qSimpleId,
    knowledgePointId: kpLinearId // Just for demo
  });

  // 3.2 Composite Question (Reading Comprehension)
  const qParentId = createId();
  const qChild1Id = createId();
  const qChild2Id = createId();

  // Parent (Passage)
  await db.insert(questions).values({
    id: qParentId,
    authorId: "user_teacher_math",
    type: "composite",
    difficulty: 3,
    content: {
      text: "Read the following passage about Algebra...\n(Long text here)...",
      assets: []
    }
  });

  // Children
  await db.insert(questions).values([
    {
      id: qChild1Id,
      authorId: "user_teacher_math",
      parentId: qParentId, // <--- Key: Nested
      type: "single_choice",
      difficulty: 2,
      content: {
        text: "What is the main topic?",
        options: [
          { id: "A", text: "Geometry", isCorrect: false },
          { id: "B", text: "Algebra", isCorrect: true }
        ]
      }
    },
    {
      id: qChild2Id,
      authorId: "user_teacher_math",
      parentId: qParentId,
      type: "text",
      difficulty: 4,
      content: {
        text: "Explain the concept of variables.",
      }
    }
  ]);

  // --- 4. Exams (New Structure) ---
  console.log("📝 Seeding Exams...");

  const examId = createId();
  const examStructure = [
    {
      type: "group",
      title: "Part 1: Basics",
      children: [
        { type: "question", questionId: qSimpleId, score: 10 }
      ]
    },
    {
      type: "group",
      title: "Part 2: Reading",
      children: [
        // For composite questions, we usually add the parent, and the system fetches children
        { type: "question", questionId: qParentId, score: 20 } 
      ]
    }
  ];

  await db.insert(exams).values({
    id: examId,
    title: "Algebra Mid-Term 2025",
    description: "Comprehensive assessment",
    creatorId: "user_teacher_math",
    status: "published",
    startTime: new Date(),
    structure: examStructure as unknown
  });

  // Link questions physically (Source of Truth)
  await db.insert(examQuestions).values([
    { examId, questionId: qSimpleId, score: 10, order: 0 },
    { examId, questionId: qParentId, score: 20, order: 1 },
    // Note: Child questions are often implicitly included or explicitly added depending on logic.
    // For this seed, we assume linking Parent is enough for the relation, 
    // but let's link children too for completeness if the query strategy requires it.
    { examId, questionId: qChild1Id, score: 0, order: 2 }, 
    { examId, questionId: qChild2Id, score: 0, order: 3 },
  ]);

  const end = performance.now();
  console.log(`✅ Seed completed in ${(end - start).toFixed(2)}ms`);
  process.exit(0);
}

seed().catch((err) => {
  console.error("❌ Seed failed:", err);
  process.exit(1);
});