import { createClient, SupabaseClient } from '@supabase/supabase-js'
import type { Database } from '~/types/database.types'

let supabaseInstance: SupabaseClient<Database> | null = null

export const useSupabase = () => {
  const config = useRuntimeConfig()
  
  if (!supabaseInstance) {
    supabaseInstance = createClient<Database>(
      config.public.supabaseUrl,
      config.public.supabaseAnonKey,
      {
        auth: {
          persistSession: true,
          autoRefreshToken: true,
          detectSessionInUrl: true,
          storage: process.client ? window.localStorage : undefined
        }
      }
    )
  }

  return supabaseInstance
}

/**
 * Composable for Supabase authentication
 */
export const useSupabaseAuth = () => {
  const supabase = useSupabase()
  const user = useState('supabase_user', () => null as any)
  const session = useState('supabase_session', () => null as any)

  // Initialize auth state
  const initAuth = async () => {
    const { data: { session: currentSession } } = await supabase.auth.getSession()
    session.value = currentSession
    user.value = currentSession?.user || null

    // Listen for auth changes
    supabase.auth.onAuthStateChange((_event, newSession) => {
      session.value = newSession
      user.value = newSession?.user || null
    })
  }

  // Call initAuth on composable mount
  if (process.client) {
    initAuth()
  }

  const signIn = async (email: string, password: string) => {
    const { data, error } = await supabase.auth.signInWithPassword({
      email,
      password
    })
    return { data, error }
  }

  const signUp = async (email: string, password: string) => {
    const { data, error } = await supabase.auth.signUp({
      email,
      password
    })
    return { data, error }
  }

  const signOut = async () => {
    const { error } = await supabase.auth.signOut()
    return { error }
  }

  return {
    user: readonly(user),
    session: readonly(session),
    signIn,
    signUp,
    signOut
  }
}