package org.oxycblt.auxio

import android.content.res.ColorStateList
import android.os.Bundle
import android.view.LayoutInflater
import android.view.MenuItem
import android.view.View
import android.view.ViewGroup
import androidx.fragment.app.Fragment
import androidx.fragment.app.activityViewModels
import androidx.navigation.NavController
import androidx.navigation.NavOptions
import androidx.navigation.fragment.NavHostFragment
import androidx.navigation.fragment.findNavController
import org.oxycblt.auxio.databinding.FragmentMainBinding
import org.oxycblt.auxio.detail.DetailViewModel
import org.oxycblt.auxio.music.MusicStore
import org.oxycblt.auxio.music.Song
import org.oxycblt.auxio.playback.PlaybackViewModel
import org.oxycblt.auxio.ui.accent
import org.oxycblt.auxio.ui.getTransparentAccent
import org.oxycblt.auxio.ui.isLandscape
import org.oxycblt.auxio.ui.toColor

/**
 * The primary "Home" [Fragment] for Auxio.
 */
class MainFragment : Fragment() {
    private val playbackModel: PlaybackViewModel by activityViewModels()
    private val detailModel: DetailViewModel by activityViewModels()

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        val binding = FragmentMainBinding.inflate(inflater)

        // If the music was cleared while the app was closed [Likely due to Auxio being suspended
        // in the background], then navigate back to LoadingFragment to reload the music.
        // This may actually not happen in normal use, but its a good failsafe.
        if (MusicStore.getInstance().songs.isEmpty()) {
            findNavController().navigate(MainFragmentDirections.actionReturnToLoading())

            return null
        }

        val colorActive = accent.first.toColor(requireContext())
        val colorInactive = getTransparentAccent(
            requireContext(), accent.first, 150
        )

        // Set up the tints for the navigation icons + text
        val navTints = ColorStateList(
            arrayOf(
                intArrayOf(-android.R.attr.state_checked),
                intArrayOf(android.R.attr.state_checked)
            ),
            intArrayOf(colorInactive, colorActive)
        )

        val navController = (
            childFragmentManager.findFragmentById(R.id.explore_nav_host)
                as NavHostFragment?
            )?.findNavController()

        // --- UI SETUP ---

        binding.lifecycleOwner = this

        binding.navBar.itemIconTintList = navTints
        binding.navBar.itemTextColor = navTints

        navController?.let { controller ->
            binding.navBar.setOnNavigationItemSelectedListener {
                navigateWithItem(controller, it)
            }
        }

        // --- VIEWMODEL SETUP ---

        // Change CompactPlaybackFragment's visibility here so that an animation occurs.
        if (!isLandscape(resources)) {
            handleCompactPlaybackVisibility(binding, playbackModel.song.value)

            playbackModel.song.observe(viewLifecycleOwner) {
                handleCompactPlaybackVisibility(binding, it)
            }
        }

        detailModel.navToItem.observe(viewLifecycleOwner) {
            if (it != null && navController != null) {
                val curDest = navController.currentDestination?.id

                // SongsFragment and SettingsFragment have no navigation pathways, so correct
                // them to the library tab instead.
                if (curDest == R.id.songs_fragment || curDest == R.id.settings_fragment) {
                    binding.navBar.selectedItemId = R.id.library_fragment
                }
            }
        }

        playbackModel.restorePlaybackIfNeeded(requireContext())

        logD("Fragment Created.")

        return binding.root
    }

    /**
     * Custom navigator code that has proper animations, unlike BottomNavigationView.setupWithNavController().
     */
    private fun navigateWithItem(navController: NavController, item: MenuItem): Boolean {
        if (navController.currentDestination!!.id != item.itemId) {
            // Create custom NavOptions myself so that animations work
            val options = NavOptions.Builder()
                .setLaunchSingleTop(true)
                .setEnterAnim(R.animator.nav_default_enter_anim)
                .setExitAnim(R.animator.nav_default_exit_anim)
                .setPopEnterAnim(R.animator.nav_default_pop_enter_anim)
                .setPopExitAnim(R.animator.nav_default_pop_exit_anim)
                .build()

            return try {
                navController.navigate(item.itemId, null, options)
                true
            } catch (e: IllegalArgumentException) {
                false
            }
        }

        return false
    }

    /**
     * Handle the visibility of CompactPlaybackFragment. Done here so that there's a nice animation.
     */
    private fun handleCompactPlaybackVisibility(binding: FragmentMainBinding, song: Song?) {
        if (song == null) {
            logD("Hiding CompactPlaybackFragment since no song is being played.")

            binding.compactPlayback.visibility = View.GONE
            playbackModel.disableAnimation()
        } else {
            binding.compactPlayback.visibility = View.VISIBLE
        }
    }
}