/*
 * Copyright (C) 2020 Conny Duck
 *
 * This file is part of Pixelcat.
 *
 * Pixelcat is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Pixelcat is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

package at.connyduck.pixelcat.components.profile

import androidx.lifecycle.MutableLiveData
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import androidx.paging.ExperimentalPagingApi
import androidx.paging.Pager
import androidx.paging.PagingConfig
import androidx.paging.cachedIn
import at.connyduck.pixelcat.components.util.Error
import at.connyduck.pixelcat.components.util.Success
import at.connyduck.pixelcat.components.util.UiState
import at.connyduck.pixelcat.db.AccountManager
import at.connyduck.pixelcat.model.Account
import at.connyduck.pixelcat.model.Relationship
import at.connyduck.pixelcat.network.FediverseApi
import kotlinx.coroutines.FlowPreview
import kotlinx.coroutines.launch
import javax.inject.Inject

class ProfileViewModel @Inject constructor(
    private val api: FediverseApi,
    private val accountManager: AccountManager
) : ViewModel() {

    val profile = MutableLiveData<UiState<Account>>()
    val relationship = MutableLiveData<UiState<Relationship>>()

    @OptIn(FlowPreview::class)
    @ExperimentalPagingApi
    val imageFlow = Pager(
        config = PagingConfig(pageSize = 10, enablePlaceholders = false),
        pagingSourceFactory = { ProfileImagePagingSource(api, accountId, accountManager) }
    ).flow
        .cachedIn(viewModelScope)

    val isSelf: Boolean
        get() = accountId == null

    private var accountId: String? = null

    fun load(reload: Boolean = false) {
        loadAccount(reload)
        if (!isSelf) {
            loadRelationship(reload)
        }
    }

    fun setAccountInfo(accountId: String?) {
        this@ProfileViewModel.accountId = accountId
        load(false)
    }

    private fun loadAccount(reload: Boolean = false) {
        if (profile.value == null || reload) {
            viewModelScope.launch {
                api.account(getAccountId()).fold(
                    {
                        profile.value = Success(it)
                    },
                    {
                        profile.value = Error(cause = it)
                    }
                )
            }
        }
    }

    private fun loadRelationship(reload: Boolean = false) {
        if (relationship.value == null || reload) {
            viewModelScope.launch {
                api.relationships(listOf(getAccountId())).fold(
                    {
                        relationship.value = Success(it.first())
                    },
                    {
                        relationship.value = Error(cause = it)
                    }
                )
            }
        }
    }

    private suspend fun getAccountId(): String {
        return accountId ?: accountManager.activeAccount()?.accountId!!
    }
}
