BelajarMediatorLive

package com.example.storyapp.ui.login

import androidx.lifecycle.LiveData
import androidx.lifecycle.MediatorLiveData
import androidx.lifecycle.ViewModel
import com.example.storyapp.data.response.auth.LoginResult
import com.example.storyapp.di.Repository
import com.example.storyapp.utils.ResultState

class LoginViewModel(private val repository: Repository) : ViewModel() {

    fun performLogin2(email: String, password: String): LiveData<ResultState<LoginResult>> =
        repository.login(email, password)

    // 1. Terapkan enkapsulasi. ViewModel memiliki state-nya sendiri.
    private val _loginResult = MediatorLiveData<ResultState<LoginResult>>()
    val loginResult: LiveData<ResultState<LoginResult>> = _loginResult

    // 2. Buat fungsi yang dipanggil UI untuk *memulai* proses login.
    // Fungsi ini tidak mengembalikan apa-apa (Unit).
    fun performLogin(email: String, password: String) {
        // Panggil fungsi repository yang mengembalikan LiveData
        val resultLiveData = repository.login(email, password)

        // 3. Tempelkan (source) LiveData dari repository ke LiveData internal ViewModel.
        _loginResult.addSource(resultLiveData) { result ->
            // 4. Update nilai LiveData internal dengan hasil dari repository.
            _loginResult.value = result
            // Hapus source setelah mendapatkan hasil agar tidak ada duplikasi observer
            _loginResult.removeSource(resultLiveData)
        }
    }
}



// di kelas Repository
fun login(
        email: String,
        password: String
    ): LiveData<ResultState<LoginResult>> = liveData {
        emit(ResultState.Loading)
        try {
            val response = apiService.login(email, password)
            if (!response.error) {
                val loginResult = response.loginResult
                userPreference.saveSession(loginResult) // Menyimpan data login ke sesi
                emit(ResultState.Success(loginResult))
            } else {
                emit(ResultState.Error(ErrorType.ApiError(response.message)))
            }
        } catch (e: HttpException) {
            if (e.code() == 401) {
                emit(ResultState.Error(ErrorType.ResourceError(R.string.error_wrong_credentials)))
            } else {
                val errorBody = e.response()?.errorBody()?.string()
                val errorResponse = Gson().fromJson(errorBody, LoginResponse::class.java)
                emit(ResultState.Error(ErrorType.ApiError(errorResponse.message)))
            }
        } catch (e: Exception) {
            emit(ResultState.Error(ErrorType.ResourceError(R.string.login_failed)))
        }
    }