package de.twomartens.troubleshooting

import android.os.Bundle
import android.view.View
import android.widget.ArrayAdapter
import android.widget.Spinner
import androidx.appcompat.app.AppCompatActivity
import androidx.constraintlayout.widget.ConstraintLayout
import androidx.lifecycle.Observer
import androidx.lifecycle.ViewModelProvider
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import com.udevel.widgetlab.TypingIndicatorView
import de.twomartens.troubleshooting.databinding.ActivityMessageListBinding
import kotlinx.coroutines.delay
import kotlinx.coroutines.launch

class MessageListActivity : AppCompatActivity() {
    private lateinit var recyclerView: RecyclerView
    private lateinit var binding: ActivityMessageListBinding
    private val viewAdapter: MessageListAdapter = MessageListAdapter()
    private lateinit var spinner: Spinner
    private lateinit var horizontalLayout: ConstraintLayout
    private lateinit var typingIndicator: TypingIndicatorView

    private lateinit var model: MessageListViewModel

    private lateinit var adapter: ArrayAdapter<SpinnerOption>

    private var showSpinner = true

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMessageListBinding.inflate(layoutInflater)
        setContentView(binding.root)

        initVariables()
        adapter = initSpinner(model, spinner)
        bindMessageObserver(viewAdapter, model)
        initButton(::step, spinner)
        val messages = initFirstChoice(adapter, model, horizontalLayout)
        receiveMessages(messages, model, typingIndicator, recyclerView, horizontalLayout)
    }

    private fun initVariables() {
        val viewManager = LinearLayoutManager(this)
        viewManager.stackFromEnd = true
        viewManager.reverseLayout = false

        model = ViewModelProvider(this)[MessageListViewModel::class.java]

        horizontalLayout = binding.layoutChatbox
        typingIndicator = binding.indicator
        typingIndicator.visibility = View.GONE
        horizontalLayout.visibility = View.GONE
        spinner = binding.spinner

        recyclerView = binding.messageList.apply {
            // use this setting to improve performance if you know that changes
            // in content do not change the layout size of the RecyclerView
            setHasFixedSize(true)

            // use a linear layout manager
            layoutManager = viewManager

            // specify an viewAdapter (see also next example)
            adapter = viewAdapter
        }
    }

    private fun initSpinner(model: MessageListViewModel,
                            spinner: Spinner): ArrayAdapter<SpinnerOption> {
        val spinnerOptions: ArrayList<SpinnerOption>? = model.spinnerOptions.value
        if (spinnerOptions != null) {
            val arrayAdapter = ArrayAdapter(this, R.layout.spinner_item, spinnerOptions)
            // Specify the layout to use when the list of choices appears
            arrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item)
            arrayAdapter.setNotifyOnChange(true)
            // Apply the adapter to the spinner
            spinner.adapter = arrayAdapter
            return arrayAdapter
        }

        return ArrayAdapter(this, android.R.layout.simple_spinner_item, ArrayList<SpinnerOption>())
    }

    private fun bindMessageObserver(viewAdapter: MessageListAdapter, model: MessageListViewModel) {
        val messageObserver = Observer<ArrayList<Message>> { messages ->
            viewAdapter.replaceMessages(messages)
        }

        model.getMessages().observe(this, messageObserver)
    }

    private fun initButton(step: (SpinnerOption) -> Unit, spinner: Spinner) {
        binding.buttonSend.setOnClickListener {
            val option = spinner.selectedItem
            if (option is SpinnerOption) {
                step(option)
            }
        }
    }

    private fun initFirstChoice(adapter: ArrayAdapter<SpinnerOption>,
                                model: MessageListViewModel,
                                horizontalLayout: ConstraintLayout): List<Message> {
        val isInitialized = model.initialized.value
        return if (isInitialized != null && !isInitialized) {
            model.spinnerOptions.value?.addAll(SpinnerOption.getOptions(
                resources.getStringArray(R.array.components_values),
                resources.getStringArray(R.array.components),
                OptionType.COMPONENT))
            adapter.notifyDataSetChanged()
            model.initialized.value = true
            listOf(Message(getString(R.string.greeting), false, System.currentTimeMillis()))
        } else {
            val spinnerVisible = model.spinnerVisible.value
            if (spinnerVisible != null && spinnerVisible) horizontalLayout.visibility = View.VISIBLE
            listOf()
        }
    }

    private fun step(selectedOption: SpinnerOption) {
        sendMessage(selectedOption, model, recyclerView, horizontalLayout)
        val messages = branch(
            selectedOption,
            model, adapter,
            ::componentSelected,
            ::problemSelected,
            ::didItWorkQuestion,
            ::pleaseTry,
            ::problemSolved,
            ::nextSolutionQuestion,
            ::doNotShowSpinner)
        receiveMessages(messages, model, typingIndicator, recyclerView, horizontalLayout, showSpinner)
    }

    private fun sendMessage(selectedOption: SpinnerOption, model: MessageListViewModel,
                            recyclerView: RecyclerView, horizontalLayout: ConstraintLayout) {
        val message = Message(selectedOption.toString(), true, System.currentTimeMillis())
        model.add(message)
        recyclerView.scrollToPosition(model.size() - 1)
        horizontalLayout.visibility = View.GONE
        model.spinnerVisible.value = false
    }

    private fun receiveMessages(messages: List<Message>,
                                model: MessageListViewModel,
                                typingIndicator: View,
                                recyclerView: RecyclerView,
                                horizontalLayout: ConstraintLayout,
                                showSpinner: Boolean = true) {
        model.uiScope.launch {
            for (message in messages) {
                typingIndicator.visibility = View.VISIBLE
                delay(1500)
                typingIndicator.visibility = View.GONE
                model.add(message)
                recyclerView.scrollToPosition(model.size() - 1)
            }
            if (messages.isNotEmpty() && showSpinner) {
                horizontalLayout.visibility = View.VISIBLE
                model.spinnerVisible.value = true
            }
        }
    }

    private fun doNotShowSpinner() {
        showSpinner = false
    }

    private fun branch(selectedOption: SpinnerOption,
                       model: MessageListViewModel,
                       adapter: ArrayAdapter<SpinnerOption>,
                       componentSelected: (MessageListViewModel, ArrayAdapter<SpinnerOption>) -> List<Message>,
                       problemSelected: (MessageListViewModel, ArrayAdapter<SpinnerOption>) -> List<Message>,
                       didItWorkQuestion: (MessageListViewModel, ArrayAdapter<SpinnerOption>) -> List<Message>,
                       pleaseTry: () -> List<Message>,
                       problemSolved: (MessageListViewModel, ArrayAdapter<SpinnerOption>) -> List<Message>,
                       nextSolutionQuestion: (MessageListViewModel, ArrayAdapter<SpinnerOption>) -> List<Message>,
                       doNotShowSpinner: () -> Unit): List<Message> {

        return when (selectedOption.type) {
            OptionType.COMPONENT -> {
                model.component.value = Component.valueOf(selectedOption.id)
                componentSelected(model, adapter)
            }
            OptionType.PROBLEM -> {
                model.problem.value = Problem.valueOf(selectedOption.id)
                problemSelected(model, adapter)
            }
            OptionType.BINARY_HAVE_YOU_TRIED -> {
                when (selectedOption.id) {
                    "YES" -> didItWorkQuestion(model, adapter)
                    else -> pleaseTry()
                }
            }
            OptionType.BINARY_DID_IT_WORK -> {
                when (selectedOption.id) {
                    "YES" -> problemSolved(model, adapter)
                    else -> nextSolutionQuestion(model, adapter)
                }
            }
            OptionType.STORY -> {
                doNotShowSpinner()
                if (selectedOption.id == "WHO_ARE_YOU") {
                    listOf(
                        Message(
                            getString(R.string.gardner_second),
                            false,
                            System.currentTimeMillis()
                        )
                    )
                }
                else {
                    listOf(
                        Message(getString(R.string.okay), false, System.currentTimeMillis()),
                        Message(getString(R.string.im_gardner), false, System.currentTimeMillis()),
                        Message(getString(R.string.okay_saves_time), false, System.currentTimeMillis()),
                        Message(getString(R.string.its_funny), false, System.currentTimeMillis()))
                }
            }
        }
    }

    private fun componentSelected(model: MessageListViewModel, adapter: ArrayAdapter<SpinnerOption>): List<Message> {
        model.spinnerOptions.value?.clear()
        model.spinnerOptions.value?.addAll(SpinnerOption.getOptions(
            resources.getStringArray(resources.getIdentifier(
                model.component.value?.name.plus("_problems_values"),
                "array",
                packageName)),
            resources.getStringArray(resources.getIdentifier(
                model.component.value?.name.plus("_problems"),
                "array",
                packageName)),
            OptionType.PROBLEM))
        adapter.notifyDataSetChanged()

        return listOf(
            Message(getString(R.string.okay), false, System.currentTimeMillis()),
            Message(getString(R.string.select_problem), false, System.currentTimeMillis())
        )
    }

    private fun problemSelected(model: MessageListViewModel, adapter: ArrayAdapter<SpinnerOption>): List<Message> {
        model.solutions.value?.addAll(resources.getStringArray(resources.getIdentifier(
            model.component.value?.name.plus("_").plus(model.problem.value?.name),
            "array",
            packageName
        )))

        val firstSolutionQuestion = getString(R.string.have_you_tried, model.solutions.value?. let { it[0] })
        model.nextSolutionIndex.value = (model.nextSolutionIndex.value ?: 0) + 1
        model.spinnerOptions.value?.clear()
        model.spinnerOptions.value?.addAll(SpinnerOption.getOptions(
            resources.getStringArray(R.array.binary_values),
            resources.getStringArray(R.array.binary),
            OptionType.BINARY_HAVE_YOU_TRIED))
        adapter.notifyDataSetChanged()

        return listOf(
            Message(getString(R.string.okay), false, System.currentTimeMillis()),
            Message(firstSolutionQuestion, false, System.currentTimeMillis())
        )
    }

    private fun didItWorkQuestion(model: MessageListViewModel, adapter: ArrayAdapter<SpinnerOption>): List<Message> {
        model.currentSolutionState.value = State.DID_IT_WORK
        model.spinnerOptions.value?.clear()
        model.spinnerOptions.value?.addAll(SpinnerOption.getOptions(
            resources.getStringArray(R.array.binary_values),
            resources.getStringArray(R.array.binary),
            OptionType.BINARY_DID_IT_WORK))
        adapter.notifyDataSetChanged()

        return listOf(
            Message(getString(R.string.okay), false, System.currentTimeMillis()),
            Message(getString(R.string.did_it_work), false, System.currentTimeMillis())
        )
    }

    private fun pleaseTry(): List<Message> {
        return listOf(
            Message(getString(R.string.okay), false, System.currentTimeMillis()),
            Message(getString(R.string.please_try), false, System.currentTimeMillis()),
            Message(getString(R.string.i_wait), false, System.currentTimeMillis()),
            Message(getString(R.string.have_you_tried, model.solutions.value?.let { it[(model.nextSolutionIndex.value ?: 1) - 1]}), false, System.currentTimeMillis())
        )
    }

    private fun problemSolved(model: MessageListViewModel, adapter: ArrayAdapter<SpinnerOption>): List<Message> {
        model.spinnerOptions.value?.clear()
        model.spinnerOptions.value?.add(SpinnerOption(
            "SAY_SOMETHING_DIFFERENT",
            getString(R.string.can_you_say_sth_different),
            OptionType.STORY))
        adapter.notifyDataSetChanged()
        return listOf(Message(getString(R.string.okay), false, System.currentTimeMillis()))
    }

    private fun nextSolutionQuestion(model: MessageListViewModel, adapter: ArrayAdapter<SpinnerOption>): List<Message> {
        if (model.nextSolutionIndex.value == model.solutions.value?.size) {
            // we exhausted all options
            var summary = """
                Component: ${model.component.value.toString()}
                Problem: ${model.problem.value.toString()}
                Tried Solutions:
            """.trimIndent()
            val solutions: ArrayList<CharSequence>? = model.solutions.value
            if (solutions != null) {
                for (solution in solutions) {
                    val item = "\n    - $solution"
                    summary = summary.plus(item)
                }
            }

            model.spinnerOptions.value?.clear()
            model.spinnerOptions.value?.add(SpinnerOption(
                "WHO_ARE_YOU",
                getString(R.string.who_are_you),
                OptionType.STORY))
            adapter.notifyDataSetChanged()

            return listOf(
                Message(getString(R.string.okay), false, System.currentTimeMillis()),
                Message(getString(R.string.sorry), false, System.currentTimeMillis()),
                Message(getString(R.string.cant_help), false, System.currentTimeMillis()),
                Message(getString(R.string.should_contact_support), false, System.currentTimeMillis()),
                Message(getString(R.string.okay_wait), false, System.currentTimeMillis()),
                Message(getString(R.string.tell_support), false, System.currentTimeMillis()),
                Message(summary, false, System.currentTimeMillis())
            )
        }
        else {
            val solutionQuestion = getString(R.string.have_you_tried, model.solutions.value?.let {it[model.nextSolutionIndex.value ?: 0]})
            model.nextSolutionIndex.value = (model.nextSolutionIndex.value ?: 0) + 1
            model.currentSolutionState.value = State.HAVE_YOU_TRIED
            model.spinnerOptions.value?.clear()
            model.spinnerOptions.value?.addAll(SpinnerOption.getOptions(
                resources.getStringArray(R.array.binary_values),
                resources.getStringArray(R.array.binary),
                OptionType.BINARY_HAVE_YOU_TRIED))
            adapter.notifyDataSetChanged()

            return listOf(
                Message(getString(R.string.okay), false, System.currentTimeMillis()),
                Message(getString(R.string.sorry), false, System.currentTimeMillis()),
                Message(solutionQuestion, false, System.currentTimeMillis())
            )
        }
    }
}