app/src/main/java/com/topit/randomcoffee/presentation/viewmodel/MenuViewModel.kt - develop - Stalnodg/RandomCoffee

app/src/main/java/com/topit/randomcoffee/presentation/viewmodel/MenuViewModel.kt

97 строк3 KB

Max

presentation: pagination moved from data to presentation, bug with broken reload fixed, ViewModel for shopping cart created

05 май 2026, 18:21

05 май 2026, 18:21c0f75ae

package com.topit.randomcoffee.presentation.viewmodel

import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import androidx.paging.PagingData
import androidx.paging.cachedIn
import com.topit.randomcoffee.domain.models.OperationResult
import com.topit.randomcoffee.domain.models.Category
import com.topit.randomcoffee.domain.models.Product
import com.topit.randomcoffee.domain.usecase.GetCategoriesUseCase
import com.topit.randomcoffee.presentation.paging.GetPagedProducts
import dagger.hilt.android.lifecycle.HiltViewModel
import kotlinx.coroutines.CancellationException
import kotlinx.coroutines.ExperimentalCoroutinesApi
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.asStateFlow
import kotlinx.coroutines.flow.flatMapLatest
import kotlinx.coroutines.flow.update
import kotlinx.coroutines.launch
import javax.inject.Inject

@OptIn(ExperimentalCoroutinesApi::class)
@HiltViewModel
class MenuViewModel @Inject constructor(
    private val getCategoriesUseCase: GetCategoriesUseCase,
    private val getPagedProducts: GetPagedProducts
) : ViewModel() {

    private val _uiState = MutableStateFlow(MenuUiState())
    val uiState = _uiState.asStateFlow()

    private val categoryIdForPaging = MutableStateFlow<Int?>(null)

    val products: Flow<PagingData<Product>> =
        categoryIdForPaging.flatMapLatest(getPagedProducts::invoke).cachedIn(viewModelScope)

    init {
        loadCategories()
    }

    private fun loadCategories() {
        viewModelScope.launch {
            try {
                when (val result = getCategoriesUseCase()) {
                    is OperationResult.Success -> {
                        _uiState.update {
                            it.copy(categories = result.data, categoriesError = null)
                        }
                        syncPagingCategoryFromSelection()
                    }
                    is OperationResult.Failure -> {
                        _uiState.update {
                            it.copy(categoriesError = "Не удалось загрузить категории")
                        }
                    }
                }
            } catch (e: CancellationException) {
                throw e
            } catch (e: Exception) {
                _uiState.update {
                    it.copy(categoriesError = e.message ?: "Не удалось загрузить категории")
                }
            }
        }
    }

    fun refreshCategories() {
        loadCategories()
    }

    fun dismissCategoriesError() {
        _uiState.update { it.copy(categoriesError = null) }
    }

    private fun syncPagingCategoryFromSelection() {
        val selection = _uiState.value.selectedTabIndexes
        val categoryId = if (selection.size == 1) {
            val index = selection.first()
            _uiState.value.categories.getOrNull(index)?.id
        } else {
            null
        }
        categoryIdForPaging.value = categoryId
    }

    fun updateSelectedTabIndexes(newSelection: Set<Int>) {
        _uiState.update { it.copy(selectedTabIndexes = newSelection) }
        syncPagingCategoryFromSelection()
    }
}

data class MenuUiState(
    val categories: List<Category> = emptyList(),
    val selectedTabIndexes: Set<Int> = emptySet(),
    val categoriesError: String? = null
)