package oppen.tva.ui

import androidx.lifecycle.ViewModel
import oppen.tva.Tva
import oppen.tva.io.gemini.Datasource
import oppen.tva.io.TvaState
import java.net.URI

class TvaViewModel: ViewModel() {

    private lateinit var gemini: Datasource
    private var onState: (state: TvaState) -> Unit = {}
    private var activeTab = 0

    val history = mutableListOf<URI>()



    fun initialise(gemini: Datasource, onState: (state: TvaState) -> Unit){
        this.gemini = gemini
        this.onState = onState

        request(URI.create(Tva.DEFAULT_HOME_CAPSULE))
        onState(TvaState.TabChange(1))
    }

    fun request(address: String) {
        request(URI.create(address))
    }

    fun request(uri: URI){
        gemini.request(uri){ state ->
            onState(state)
        }
    }

    fun canGoBack(): Boolean = history.size > 1

    @ExperimentalStdlibApi
    fun goBack(){
        when {
            history.size >= 2 -> {
                val previous = history[history.size - 2]
                history.removeLast()
                request(previous)
            }
        }
    }
}