/*
 * This file is part of GNU Taler
 * (C) 2020 Taler Systems S.A.
 *
 * GNU Taler 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, or (at your option) any later version.
 *
 * GNU Taler 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
 * GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
 */

package net.taler.wallet.payment

import android.annotation.SuppressLint
import android.graphics.Bitmap
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.View.GONE
import android.view.View.VISIBLE
import android.view.ViewGroup
import androidx.fragment.app.Fragment
import androidx.fragment.app.activityViewModels
import androidx.lifecycle.Observer
import androidx.lifecycle.observe
import androidx.navigation.fragment.findNavController
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.transition.TransitionManager.beginDelayedTransition
import kotlinx.android.synthetic.main.payment_bottom_bar.*
import kotlinx.android.synthetic.main.payment_details.*
import net.taler.wallet.Amount
import net.taler.wallet.R
import net.taler.wallet.WalletViewModel
import net.taler.wallet.fadeIn
import net.taler.wallet.fadeOut

/**
 * Show a payment and ask the user to accept/decline.
 */
class PromptPaymentFragment : Fragment(), ProductImageClickListener {

    private val model: WalletViewModel by activityViewModels()
    private val paymentManager by lazy { model.paymentManager }
    private val adapter = ProductAdapter(this)

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        return inflater.inflate(R.layout.fragment_prompt_payment, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        paymentManager.payStatus.observe(viewLifecycleOwner, this::onPaymentStatusChanged)
        paymentManager.detailsShown.observe(viewLifecycleOwner, Observer { shown ->
            beginDelayedTransition(view as ViewGroup)
            val res = if (shown) R.string.payment_hide_details else R.string.payment_show_details
            detailsButton.setText(res)
            productsList.visibility = if (shown) VISIBLE else GONE
        })

        detailsButton.setOnClickListener {
            paymentManager.toggleDetailsShown()
        }
        productsList.apply {
            adapter = this@PromptPaymentFragment.adapter
            layoutManager = LinearLayoutManager(requireContext())
        }

        abortButton.setOnClickListener {
            paymentManager.abortPay()
            findNavController().navigateUp()
        }
    }

    override fun onDestroy() {
        super.onDestroy()
        if (!requireActivity().isChangingConfigurations) {
            paymentManager.abortPay()
        }
    }

    private fun showLoading(show: Boolean) {
        model.showProgressBar.value = show
        if (show) {
            progressBar.fadeIn()
        } else {
            progressBar.fadeOut()
        }
    }

    private fun onPaymentStatusChanged(payStatus: PayStatus) {
        when (payStatus) {
            is PayStatus.Prepared -> {
                showLoading(false)
                showOrder(payStatus.contractTerms, payStatus.totalFees)
                confirmButton.isEnabled = true
                confirmButton.setOnClickListener {
                    model.showProgressBar.value = true
                    paymentManager.confirmPay(payStatus.proposalId)
                    confirmButton.fadeOut()
                    confirmProgressBar.fadeIn()
                }
            }
            is PayStatus.InsufficientBalance -> {
                showLoading(false)
                showOrder(payStatus.contractTerms, null)
                errorView.setText(R.string.payment_balance_insufficient)
                errorView.fadeIn()
            }
            is PayStatus.Success -> {
                showLoading(false)
                paymentManager.resetPayStatus()
                findNavController().navigate(R.id.action_promptPayment_to_paymentSuccessful)
            }
            is PayStatus.AlreadyPaid -> {
                showLoading(false)
                paymentManager.resetPayStatus()
                findNavController().navigate(R.id.action_promptPayment_to_alreadyPaid)
            }
            is PayStatus.Error -> {
                showLoading(false)
                errorView.text = getString(R.string.payment_error, payStatus.error)
                errorView.fadeIn()
            }
            is PayStatus.None -> {
                // No payment active.
                showLoading(false)
            }
            is PayStatus.Loading -> {
                // Wait until loaded ...
                showLoading(true)
            }
        }
    }

    private fun showOrder(contractTerms: ContractTerms, totalFees: Amount?) {
        orderView.text = contractTerms.summary
        adapter.setItems(contractTerms.products)
        if (contractTerms.products.size == 1) paymentManager.toggleDetailsShown()
        val amount = contractTerms.amount
        @SuppressLint("SetTextI18n")
        totalView.text = "${amount.amount} ${amount.currency}"
        if (totalFees != null && !totalFees.isZero()) {
            val fee = "${totalFees.amount} ${totalFees.currency}"
            feeView.text = getString(R.string.payment_fee, fee)
            feeView.fadeIn()
        } else {
            feeView.visibility = GONE
        }
        orderLabelView.fadeIn()
        orderView.fadeIn()
        if (contractTerms.products.size > 1) detailsButton.fadeIn()
        totalLabelView.fadeIn()
        totalView.fadeIn()
    }

    override fun onImageClick(image: Bitmap) {
        val f = ProductImageFragment.new(image)
        f.show(parentFragmentManager, "image")
    }

}