/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

package org.mozilla.fenix.library.history

import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.core.view.isVisible
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.SimpleItemAnimator
import kotlinx.android.synthetic.main.component_history.*
import kotlinx.android.synthetic.main.component_history.view.*
import mozilla.components.support.base.feature.UserInteractionHandler
import org.mozilla.fenix.R
import org.mozilla.fenix.library.LibraryPageView
import org.mozilla.fenix.library.SelectionInteractor
import org.mozilla.fenix.theme.ThemeManager

/**
 * Interface for the HistoryViewInteractor. This interface is implemented by objects that want
 * to respond to user interaction on the HistoryView
 */
interface HistoryViewInteractor : SelectionInteractor<HistoryItem> {

    /**
     * Called on backpressed to exit edit mode
     */
    fun onBackPressed(): Boolean

    /**
     * Called when the mode is switched so we can invalidate the menu
     */
    fun onModeSwitched()

    /**
     * Copies the URL of a history item to the copy-paste buffer.
     *
     * @param item the history item to copy the URL from
     */
    fun onCopyPressed(item: HistoryItem)

    /**
     * Opens the share sheet for a history item.
     *
     * @param item the history item to share
     */
    fun onSharePressed(item: HistoryItem)

    /**
     * Opens a history item in a new tab.
     *
     * @param item the history item to open in a new tab
     */
    fun onOpenInNormalTab(item: HistoryItem)

    /**
     * Opens a history item in a private tab.
     *
     * @param item the history item to open in a private tab
     */
    fun onOpenInPrivateTab(item: HistoryItem)

    /**
     * Called when delete all is tapped
     */
    fun onDeleteAll()

    /**
     * Called when multiple history items are deleted
     * @param items the history items to delete
     */
    fun onDeleteSome(items: Set<HistoryItem>)

    /**
     * Called when the user requests a sync of the history
     */
    fun onRequestSync()

    /**
     * Called when the user clicks on recently closed tab button.
     */
    fun onRecentlyClosedClicked()
}

/**
 * View that contains and configures the History List
 */
class HistoryView(
    container: ViewGroup,
    val interactor: HistoryInteractor
) : LibraryPageView(container), UserInteractionHandler {

    val view: View = LayoutInflater.from(container.context)
        .inflate(R.layout.component_history, container, true)

    var mode: HistoryFragmentState.Mode = HistoryFragmentState.Mode.Normal
        private set

    val historyAdapter = HistoryAdapter(interactor)
    private val layoutManager = LinearLayoutManager(container.context)

    init {
        view.history_list.apply {
            layoutManager = this@HistoryView.layoutManager
            adapter = historyAdapter
            (itemAnimator as SimpleItemAnimator).supportsChangeAnimations = false
        }

        val primaryTextColor =
            ThemeManager.resolveAttribute(R.attr.primaryText, context)
        view.swipe_refresh.setColorSchemeColors(primaryTextColor)
        view.swipe_refresh.setOnRefreshListener {
            interactor.onRequestSync()
            view.history_list.scrollToPosition(0)
        }
    }

    fun update(state: HistoryFragmentState) {
        val oldMode = mode

        view.progress_bar.isVisible = state.isDeletingItems
        view.swipe_refresh.isRefreshing = state.mode === HistoryFragmentState.Mode.Syncing
        view.swipe_refresh.isEnabled =
            state.mode === HistoryFragmentState.Mode.Normal || state.mode === HistoryFragmentState.Mode.Syncing
        mode = state.mode

        historyAdapter.updatePendingDeletionIds(state.pendingDeletionIds)

        updateEmptyState(state.pendingDeletionIds.size != historyAdapter.currentList?.size)

        historyAdapter.updateMode(state.mode)
        val first = layoutManager.findFirstVisibleItemPosition()
        val last = layoutManager.findLastVisibleItemPosition() + 1
        historyAdapter.notifyItemRangeChanged(first, last - first)

        if (state.mode::class != oldMode::class) {
            interactor.onModeSwitched()
        }

        if (state.mode is HistoryFragmentState.Mode.Editing) {
            val unselectedItems = oldMode.selectedItems - state.mode.selectedItems

            state.mode.selectedItems.union(unselectedItems).forEach { item ->
                historyAdapter.notifyItemChanged(item.id)
            }
        }

        when (val mode = state.mode) {
            is HistoryFragmentState.Mode.Normal -> {
                setUiForNormalMode(
                    context.getString(R.string.library_history)
                )
            }
            is HistoryFragmentState.Mode.Editing -> {
                setUiForSelectingMode(
                    context.getString(R.string.history_multi_select_title, mode.selectedItems.size)
                )
            }
        }
    }

    fun updateEmptyState(userHasHistory: Boolean) {
        history_list.isVisible = userHasHistory
        history_empty_view.isVisible = !userHasHistory
        if (!userHasHistory) {
            history_empty_view.announceForAccessibility(context.getString(R.string.history_empty_message))
        }
    }

    override fun onBackPressed(): Boolean {
        return interactor.onBackPressed()
    }
}