package cash.z.ecc.android.ui.history

import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import androidx.fragment.app.activityViewModels
import androidx.lifecycle.lifecycleScope
import androidx.paging.PagedList
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import cash.z.ecc.android.R
import cash.z.ecc.android.databinding.FragmentHistoryBinding
import cash.z.ecc.android.ext.*
import cash.z.ecc.android.feedback.Report
import cash.z.ecc.android.feedback.Report.Tap.HISTORY_BACK
import cash.z.ecc.android.sdk.db.entity.ConfirmedTransaction
import cash.z.ecc.android.sdk.ext.collectWith
import cash.z.ecc.android.sdk.ext.toAbbreviatedAddress
import cash.z.ecc.android.sdk.model.WalletBalance
import cash.z.ecc.android.ui.base.BaseFragment
import cash.z.ecc.android.util.twig
import kotlinx.coroutines.flow.filterNotNull
import kotlinx.coroutines.launch

class HistoryFragment : BaseFragment<FragmentHistoryBinding>() {
    override val screen = Report.Screen.HISTORY

    private val viewModel: HistoryViewModel by activityViewModels()

    private lateinit var transactionAdapter: TransactionAdapter<ConfirmedTransaction>

    override fun inflate(inflater: LayoutInflater): FragmentHistoryBinding =
        FragmentHistoryBinding.inflate(inflater)

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        twig("HistoryFragment.onViewCreated")
        super.onViewCreated(view, savedInstanceState)
        initTransactionUI()
        binding.backButtonHitArea.onClickNavUp { tapped(HISTORY_BACK) }
        lifecycleScope.launch {
            binding.textAddress.text = viewModel.getAddress().toAbbreviatedAddress(10, 10)
        }
    }

    override fun onResume() {
        twig("HistoryFragment.onResume")
        super.onResume()
        viewModel.balance.filterNotNull().collectWith(resumedScope) {
            onBalanceUpdated(it)
        }
        viewModel.transactions.collectWith(resumedScope) { onTransactionsUpdated(it) }
    }

    private fun onBalanceUpdated(balance: WalletBalance) {
        if (balance.available.value < 0) {
            binding.textBalanceAvailable.text = "Updating"
            return
        }

        binding.textBalanceAvailable.text = WalletZecFormmatter.toZecStringShort(balance.available)
        val change = balance.pending
        binding.textBalanceDescription.apply {
            goneIf(change.value <= 0L)
            val changeString = WalletZecFormmatter.toZecStringFull(change)
            val expecting = R.string.home_banner_expecting.toAppString(true)
            val symbol = getString(R.string.symbol)
            text = "($expecting +$changeString $symbol)".toColoredSpan(R.color.text_light, "+$changeString")
        }
    }

    private fun initTransactionUI() {
        twig("HistoryFragment.initTransactionUI")
        transactionAdapter = TransactionAdapter()
        transactionAdapter.stateRestorationPolicy =
            RecyclerView.Adapter.StateRestorationPolicy.PREVENT_WHEN_EMPTY

        binding.recyclerTransactions.apply {
            layoutManager = LinearLayoutManager(activity, LinearLayoutManager.VERTICAL, false)
            adapter = transactionAdapter
        }
    }

    private fun onTransactionsUpdated(transactions: List<ConfirmedTransaction>) {
        twig("HistoryFragment.onTransactionsUpdated")
        transactions.size.let { newCount ->
            twig("got a new paged list of transactions of length $newCount")
            binding.groupEmptyViews.goneIf(newCount > 0)

            // tricky: we handle two types of lists, empty and PagedLists. It's not easy to construct an empty PagedList so the SDK currently returns an emptyList() but that will not cast to a PagedList
            if (newCount == 0) {
                transactionAdapter.submitList(null)
            } else {
                // tricky: for now, explicitly fail (cast exception) if the transactions are not in a PagedList. Otherwise, this would silently fail to show items and be hard to debug if we're ever passed a non-empty list that isn't an instance of PagedList. This awkwardness will go away when we switch to Paging3
                transactionAdapter.submitList(transactions as PagedList<ConfirmedTransaction>)
            }
        }
    }

    // TODO: maybe implement this for better fade behavior. Or do an actual scroll behavior instead, yeah do that. Or an item decoration.
    fun onLastItemShown(item: ConfirmedTransaction, position: Int) {
        binding.footerFade.alpha = position.toFloat() / (binding.recyclerTransactions.adapter?.itemCount ?: 1)
    }
}