Yuito-app-android/app/src/main/java/com/keylesspalace/tusky/components/followedtags/FollowedTagsActivity.kt

package com.keylesspalace.tusky.components.followedtags

import android.os.Bundle
import android.util.Log
import androidx.activity.viewModels
import androidx.lifecycle.lifecycleScope
import androidx.paging.LoadState
import androidx.recyclerview.widget.DividerItemDecoration
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.SimpleItemAnimator
import at.connyduck.calladapter.networkresult.fold
import com.google.android.material.snackbar.Snackbar
import com.keylesspalace.tusky.BaseActivity
import com.keylesspalace.tusky.R
import com.keylesspalace.tusky.databinding.ActivityFollowedTagsBinding
import com.keylesspalace.tusky.di.ViewModelFactory
import com.keylesspalace.tusky.interfaces.HashtagActionListener
import com.keylesspalace.tusky.network.MastodonApi
import com.keylesspalace.tusky.util.hide
import com.keylesspalace.tusky.util.show
import com.keylesspalace.tusky.util.viewBinding
import com.keylesspalace.tusky.util.visible
import kotlinx.coroutines.flow.collectLatest
import kotlinx.coroutines.launch
import java.io.IOException
import javax.inject.Inject

class FollowedTagsActivity : BaseActivity(), HashtagActionListener {
    @Inject
    lateinit var api: MastodonApi

    @Inject
    lateinit var viewModelFactory: ViewModelFactory

    private val binding by viewBinding(ActivityFollowedTagsBinding::inflate)
    private val viewModel: FollowedTagsViewModel by viewModels { viewModelFactory }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setContentView(binding.root)
        setSupportActionBar(binding.includedToolbar.toolbar)
        supportActionBar?.run {
            setTitle(R.string.title_followed_hashtags)
            // Back button
            setDisplayHomeAsUpEnabled(true)
            setDisplayShowHomeEnabled(true)
        }

        setupAdapter().let { adapter ->
            setupRecyclerView(adapter)

            lifecycleScope.launch {
                viewModel.pager.collectLatest { pagingData ->
                    adapter.submitData(pagingData)
                }
            }
        }
    }

    private fun setupRecyclerView(adapter: FollowedTagsAdapter) {
        binding.followedTagsView.adapter = adapter
        binding.followedTagsView.setHasFixedSize(true)
        binding.followedTagsView.layoutManager = LinearLayoutManager(this)
        binding.followedTagsView.addItemDecoration(DividerItemDecoration(this, DividerItemDecoration.VERTICAL))
        (binding.followedTagsView.itemAnimator as SimpleItemAnimator).supportsChangeAnimations = false
    }

    private fun setupAdapter(): FollowedTagsAdapter {
        return FollowedTagsAdapter(this, viewModel).apply {
            addLoadStateListener { loadState ->
                binding.followedTagsProgressBar.visible(loadState.refresh == LoadState.Loading && itemCount == 0)

                if (loadState.refresh is LoadState.Error) {
                    binding.followedTagsView.hide()
                    binding.followedTagsMessageView.show()
                    val errorState = loadState.refresh as LoadState.Error
                    if (errorState.error is IOException) {
                        binding.followedTagsMessageView.setup(R.drawable.elephant_offline, R.string.error_network) { retry() }
                    } else {
                        binding.followedTagsMessageView.setup(R.drawable.elephant_error, R.string.error_generic) { retry() }
                    }
                    Log.w(TAG, "error loading followed hashtags", errorState.error)
                } else {
                    binding.followedTagsView.show()
                    binding.followedTagsMessageView.hide()
                }
            }
        }
    }

    private fun follow(tagName: String, position: Int) {
        lifecycleScope.launch {
            api.followTag(tagName).fold(
                {
                    viewModel.tags.add(position, it)
                    viewModel.currentSource?.invalidate()
                },
                {
                    Snackbar.make(
                        this@FollowedTagsActivity,
                        binding.followedTagsView,
                        getString(R.string.error_following_hashtag_format, tagName),
                        Snackbar.LENGTH_SHORT
                    )
                        .show()
                }
            )
        }
    }

    override fun unfollow(tagName: String, position: Int) {
        lifecycleScope.launch {
            api.unfollowTag(tagName).fold(
                {
                    viewModel.tags.removeAt(position)
                    Snackbar.make(
                        this@FollowedTagsActivity,
                        binding.followedTagsView,
                        getString(R.string.confirmation_hashtag_unfollowed, tagName),
                        Snackbar.LENGTH_LONG
                    )
                        .setAction(R.string.action_undo) {
                            follow(tagName, position)
                        }
                        .show()
                    viewModel.currentSource?.invalidate()
                },
                {
                    Snackbar.make(
                        this@FollowedTagsActivity,
                        binding.followedTagsView,
                        getString(
                            R.string.error_unfollowing_hashtag_format,
                            tagName
                        ),
                        Snackbar.LENGTH_SHORT
                    )
                        .show()
                }
            )
        }
    }

    companion object {
        const val TAG = "FollowedTagsActivity"
    }
}