/*
 * Copyright (C) 2022 E FOUNDATION
 *
 * This program 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.
 *
 * This program 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 foundation.e.advancedprivacy.common

import kotlinx.coroutines.FlowPreview
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.flow
import kotlin.time.Duration

@FlowPreview
fun <T> Flow<T>.throttleFirst(windowDuration: Duration): Flow<T> = flow {
    var lastEmissionTime = 0L
    collect { upstream ->
        val currentTime = System.currentTimeMillis()
        val mayEmit = currentTime - lastEmissionTime > windowDuration.inWholeMilliseconds
        if (mayEmit) {
            lastEmissionTime = currentTime
            emit(upstream)
        }
    }
}