localStorageService.ts

import { Student, User } from './types';

const STORAGE_KEY_TEACHER_NAME = 'phonicstrack_teacher_name';
const STORAGE_KEY_STUDENTS = 'phonicstrack_students';
const STORAGE_KEY_CURRENT_USER = 'phonicstrack_current_user';


// Simple in-memory store for current user (cleared on browser refresh)
let currentUser: User | null = null;

// Initialize stored data if needed
const initializeStorage = () => {
  if (!localStorage.getItem(STORAGE_KEY_STUDENTS)) {
    localStorage.setItem(STORAGE_KEY_STUDENTS, JSON.stringify([]));
  }
};

export const localStorageService = {



  getCurrentUser: (): User | null => {
    if (currentUser) return currentUser;
    
    const stored = localStorage.getItem(STORAGE_KEY_CURRENT_USER);
    if (stored) {
      try {
        currentUser = JSON.parse(stored);
        return currentUser;
      } catch {
        return null;
      }
    }
    return null;
  },

  // Get teacher name
  getTeacherName: (): string => {
    return localStorage.getItem(STORAGE_KEY_TEACHER_NAME) || 'Teacher';
  },

  // Update teacher name
  updateTeacherName: (name: string): void => {
    localStorage.setItem(STORAGE_KEY_TEACHER_NAME, name);
  },

  // Student methods
  getStudentsByUserId: (userId: string): Student[] => {
    initializeStorage();
    const students = JSON.parse(localStorage.getItem(STORAGE_KEY_STUDENTS) || '[]') as Student[];
    return students.filter(s => s.userId === userId);
  },

  addStudent: (student: Omit<Student, 'id'>): Student => {
    initializeStorage();
    const students = JSON.parse(localStorage.getItem(STORAGE_KEY_STUDENTS) || '[]') as Student[];
    const id = `student_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`;
    const newStudent: Student = { ...student, id };
    students.push(newStudent);
    localStorage.setItem(STORAGE_KEY_STUDENTS, JSON.stringify(students));
    return newStudent;
  },

  updateStudent: (student: Student): Student => {
    initializeStorage();
    const students = JSON.parse(localStorage.getItem(STORAGE_KEY_STUDENTS) || '[]') as Student[];
    const index = students.findIndex(s => s.id === student.id);
    
    if (index === -1) {
      throw new Error('Student not found');
    }

    students[index] = student;
    localStorage.setItem(STORAGE_KEY_STUDENTS, JSON.stringify(students));
    return student;
  },

  deleteStudent: (studentId: string): void => {
    initializeStorage();
    const students = JSON.parse(localStorage.getItem(STORAGE_KEY_STUDENTS) || '[]') as Student[];
    const filtered = students.filter(s => s.id !== studentId);
    localStorage.setItem(STORAGE_KEY_STUDENTS, JSON.stringify(filtered));
  },

  // Batch operations
  addMultipleStudents: (studentsData: Omit<Student, 'id'>[]): Student[] => {
    initializeStorage();
    const students = JSON.parse(localStorage.getItem(STORAGE_KEY_STUDENTS) || '[]') as Student[];
    
    const newStudents = studentsData.map(data => ({
      ...data,
      id: `student_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`
    }));

    students.push(...newStudents);
    localStorage.setItem(STORAGE_KEY_STUDENTS, JSON.stringify(students));
    return newStudents;
  },

  // Clear all data (for dev/testing)
  clearAllData: (): void => {
    localStorage.removeItem(STORAGE_KEY_TEACHER_NAME);
    localStorage.removeItem(STORAGE_KEY_STUDENTS);
    localStorage.removeItem(STORAGE_KEY_CURRENT_USER);
    currentUser = null;
  },

  // Remove only students data (preserve teacher name/current user)
  clearStudents: (): void => {
    localStorage.removeItem(STORAGE_KEY_STUDENTS);
    initializeStorage();
  }
};