package oppen.gem.ui

import androidx.lifecycle.ViewModel
import oppen.gem.Gem
import oppen.gem.io.gemini.Datasource
import oppen.gem.io.GemState
import oppen.gem.io.bookmarks.BookmarksDatasource
import java.net.URI

class GemViewModel: ViewModel() {

    private lateinit var gemini: Datasource
    private lateinit var bookmarks: BookmarksDatasource
    private var onState: (state: GemState) -> Unit = {}

    private val history = mutableListOf<URI>()

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

        request(URI.create(Gem.DEFAULT_HOME_CAPSULE))//todo - regression: should check prefs...
        onState(GemState.TabChange(1))
    }

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

    fun request(uri: URI){
        gemini.request(uri){ state ->
            if(history.isEmpty()){
                history.add(uri)
            }else if(history.last().toString() != uri.toString()) {
                history.add(uri)
            }
            onState(state)
        }
    }

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

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

                println("Requesting history item: $previous")
                request(previous)
                logHistory()
            }
        }
    }

    private fun logHistory(){
        history.forEach { uri ->
            println("History: $uri")
        }
    }
}