HumanLearning2021/HumanLearningApp

package com.github.HumanLearning2021.HumanLearningApp.view.dataset_editing

import android.content.Intent
import android.graphics.BitmapFactory
import android.net.Uri
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.appcompat.app.AlertDialog
import androidx.core.content.ContextCompat.getColor
import androidx.core.os.bundleOf
import androidx.fragment.app.Fragment
import androidx.fragment.app.FragmentActivity
import androidx.fragment.app.setFragmentResult
import androidx.navigation.fragment.findNavController
import androidx.navigation.fragment.navArgs
import com.bumptech.glide.Glide
import com.github.HumanLearning2021.HumanLearningApp.R
import com.github.HumanLearning2021.HumanLearningApp.databinding.FragmentSelectPictureBinding
import com.github.HumanLearning2021.HumanLearningApp.model.Category
import com.github.HumanLearning2021.HumanLearningApp.model.Id

/**
 * Fragment used to select a picture from the user's device which is then added to the dataset.
 */
class SelectPictureFragment : Fragment() {
    private lateinit var parentActivity: FragmentActivity
    private var selectedPicture: Uri? = null
    private var selectedCategory: Category? = null
    private var categories = setOf<Category>()
    private lateinit var datasetId: Id // ugly hack, but necessary to navigate back to display dataset fragment. Popping backstack doesn't seem to work

    private var _binding: FragmentSelectPictureBinding? = null
    private val binding get() = _binding!!

    private val args: SelectPictureFragmentArgs by navArgs()

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View {
        parentActivity = requireActivity()



        _binding = FragmentSelectPictureBinding.inflate(inflater, container, false)
        return binding.root
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        datasetId = args.datasetId
        categories = categories.plus(args.categories.toList())

        binding.buttonChoosePicture.setOnClickListener {
            /**
             * Allow the user to select an existing picture in their device.
             */
            launchOpenPicture()
        }

        binding.buttonSelectCategorySelectPictureFragment.setOnClickListener {
            /**
             * Allow the user to select the category of the selected picture.
             */
            onSelectCategoryButton()
        }

        /**
         * sends the picture to the display dataset fragment who adds the picture to the dataset.
         */
        binding.buttonSaveSelectPictureFragment.setOnClickListener {
            setFragmentResult(
                AddPictureFragment.REQUEST_KEY,
                bundleOf("chosenCategory" to selectedCategory!!, "pictureUri" to selectedPicture!!)
            )
            findNavController().popBackStack()
        }
    }

    private fun launchOpenPicture() {
        val intent = Intent(Intent.ACTION_OPEN_DOCUMENT).apply {
            addCategory(Intent.CATEGORY_OPENABLE)
            type = "image/*"
        }
        /** This method is deprecated. However, the [official documentation][1] recommends using it
         * for this purpose as of 2021-05-12. We do not currently know how to avoid this.
         *
         * [1]:
         * https://developer.android.com/training/data-storage/shared/documents-files#open-file
         */
        @Suppress("DEPRECATION")  // FIXME: use something non-deprecated
        startActivityForResult(intent, RC_OPEN_PICTURE)
    }

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        @Suppress("DEPRECATION")
        super.onActivityResult(requestCode, resultCode, data)
        when (requestCode) {
            RC_OPEN_PICTURE -> {
                data?.data?.also {
                    val bytes = requireContext().contentResolver.openInputStream(it).use { src ->
                        src!!.readBytes()
                    }
                    val bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.size)
                    selectedPicture =
                        AddPictureFragment.applyImageSizeReduction(bitmap, requireContext())
                    displayPicture(it)
                    notifySaveButton()
                }
            }
        }
    }


    override fun onDestroyView() {
        super.onDestroyView()
        _binding = null
    }

    private fun displayPicture(pic: Uri) {
        Glide.with(this).load(pic).into(binding.imageViewSelectPicturePreview)
    }

    private fun onSelectCategoryButton() {
        val builder = AlertDialog.Builder(parentActivity)
        builder.apply {
            setTitle(getString(R.string.AddPicture_categorySelectionDialogTitle))
            setItems(categories.map { cat -> cat.name }.toTypedArray()) { _, category_index ->
                val button = binding.buttonSelectCategorySelectPictureFragment
                categories.elementAt(category_index).let {
                    button.text = it.name
                    selectedCategory = it
                    button.apply {
                        setBackgroundColor(getColor(parentActivity, R.color.button_set))
                        button.setTextColor(getColor(parentActivity, R.color.black))
                    }
                    notifySaveButton()
                }
            }
            val dialog = builder.create()
            dialog.show()
        }
    }


    private fun notifySaveButton() {
        /**
         * the save button is only enabled if the picture and the category have been selected.
         */
        binding.buttonSaveSelectPictureFragment.isEnabled =
            selectedCategory != null && selectedPicture != null
    }

    companion object {
        val RC_OPEN_PICTURE = "open picture".hashCode()
    }
}