import { create } from 'zustand'
import { supabase } from '@/lib/supabase'
import type { User } from '@/types'

interface AuthState {
  user: User | null
  isLoading: boolean
  login: (email: string, password: string) => Promise<void>
  register: (name: string, email: string, password: string) => Promise<void>
  logout: () => Promise<void>
  initialize: () => Promise<void>
}

function sessionToUser(session: { user: { id: string; email?: string; user_metadata?: { name?: string } } } | null): User | null {
  if (!session) return null
  const { id, email, user_metadata } = session.user
  const name = user_metadata?.name ?? email?.split('@')[0] ?? 'Người dùng'
  return { id, email: email ?? '', name }
}

export const useAuthStore = create<AuthState>((set) => ({
  user: null,
  isLoading: true,

  initialize: async () => {
    set({ isLoading: true })

    // Restore existing session (JWT in localStorage via Supabase SDK)
    const { data: { session } } = await supabase.auth.getSession()
    set({ user: sessionToUser(session), isLoading: false })

    // Keep state in sync across tabs and token refresh
    supabase.auth.onAuthStateChange((_event, newSession) => {
      set({ user: sessionToUser(newSession), isLoading: false })
    })
  },

  login: async (email, password) => {
    const { error } = await supabase.auth.signInWithPassword({ email, password })
    if (error) throw new Error(mapAuthError(error.message))
    // onAuthStateChange fires and updates user state
  },

  register: async (name, email, password) => {
    const { error } = await supabase.auth.signUp({
      email,
      password,
      options: { data: { name } },
    })
    if (error) throw new Error(mapAuthError(error.message))
    // onAuthStateChange fires and updates user state
  },

  logout: async () => {
    await supabase.auth.signOut()
    // onAuthStateChange fires → user set to null
  },
}))

function mapAuthError(msg: string): string {
  if (msg.includes('already registered') || msg.includes('already exists')) {
    return 'Email này đã được sử dụng. Vui lòng đăng nhập.'
  }
  if (msg.includes('Invalid login credentials') || msg.includes('invalid_credentials')) {
    return 'Sai email hoặc mật khẩu. Vui lòng kiểm tra lại.'
  }
  if (msg.includes('Email not confirmed')) {
    return 'Email chưa được xác nhận.'
  }
  return 'Đã có lỗi xảy ra. Vui lòng thử lại.'
}