/* 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 mozilla.components.feature.addons.ui

import android.annotation.SuppressLint
import android.graphics.Bitmap
import android.graphics.Typeface
import android.graphics.drawable.BitmapDrawable
import android.graphics.drawable.TransitionDrawable
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ImageView
import android.widget.RatingBar
import android.widget.TextView
import androidx.annotation.ColorRes
import androidx.annotation.DimenRes
import androidx.annotation.DrawableRes
import androidx.annotation.StringRes
import androidx.annotation.VisibleForTesting
import androidx.core.content.ContextCompat
import androidx.core.view.isVisible
import androidx.recyclerview.widget.DiffUtil
import androidx.recyclerview.widget.ListAdapter
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.Dispatchers.Main
import kotlinx.coroutines.Job
import kotlinx.coroutines.launch
import mozilla.components.feature.addons.Addon
import mozilla.components.feature.addons.R
import mozilla.components.feature.addons.amo.AddonCollectionProvider
import mozilla.components.feature.addons.ui.CustomViewHolder.AddonViewHolder
import mozilla.components.feature.addons.ui.CustomViewHolder.SectionViewHolder
import mozilla.components.feature.addons.ui.CustomViewHolder.UnsupportedSectionViewHolder
import mozilla.components.support.base.log.logger.Logger
import mozilla.components.support.ktx.android.content.res.resolveAttribute
import java.io.IOException

private const val VIEW_HOLDER_TYPE_SECTION = 0
private const val VIEW_HOLDER_TYPE_NOT_YET_SUPPORTED_SECTION = 1
private const val VIEW_HOLDER_TYPE_ADDON = 2

/**
 * An adapter for displaying add-on items. This will display information related to the state of
 * an add-on such as recommended, unsupported or installed. In addition, it will perform actions
 * such as installing an add-on.
 *
 * @property addonCollectionProvider Provider of AMO collection API.
 * @property addonsManagerDelegate Delegate that will provides method for handling the add-on items.
 * @param addons The list of add-on based on the AMO store.
 * @property style Indicates how items should look like.
 * @property excludedAddonIDs The list of add-on IDs to be excluded from the recommended section.
 */
@Suppress("LargeClass")
class AddonsManagerAdapter(
    private val addonCollectionProvider: AddonCollectionProvider,
    private val addonsManagerDelegate: AddonsManagerAdapterDelegate,
    addons: List<Addon>,
    private val style: Style? = null,
    private val excludedAddonIDs: List<String> = emptyList()
) : ListAdapter<Any, CustomViewHolder>(DifferCallback) {
    private val scope = CoroutineScope(Dispatchers.IO)
    private val logger = Logger("AddonsManagerAdapter")

    /**
     * Represents all the add-ons that will be distributed in multiple headers like
     * enabled, recommended and unsupported, this help have the data source of the items,
     * displayed in the UI.
     */
    @VisibleForTesting
    internal var addonsMap: MutableMap<String, Addon> = addons.associateBy({ it.id }, { it }).toMutableMap()

    init {
        submitList(createListWithSections(addons, excludedAddonIDs))
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): CustomViewHolder {
        return when (viewType) {
            VIEW_HOLDER_TYPE_ADDON -> createAddonViewHolder(parent)
            VIEW_HOLDER_TYPE_SECTION -> createSectionViewHolder(parent)
            VIEW_HOLDER_TYPE_NOT_YET_SUPPORTED_SECTION -> createUnsupportedSectionViewHolder(parent)
            else -> throw IllegalArgumentException("Unrecognized viewType")
        }
    }

    private fun createSectionViewHolder(parent: ViewGroup): CustomViewHolder {
        val context = parent.context
        val inflater = LayoutInflater.from(context)
        val view = inflater.inflate(R.layout.mozac_feature_addons_section_item, parent, false)
        val titleView = view.findViewById<TextView>(R.id.title)
        val divider = view.findViewById<View>(R.id.divider)
        return SectionViewHolder(view, titleView, divider)
    }

    private fun createUnsupportedSectionViewHolder(parent: ViewGroup): CustomViewHolder {
        val context = parent.context
        val inflater = LayoutInflater.from(context)
        val view = inflater.inflate(
            R.layout.mozac_feature_addons_section_unsupported_section_item,
            parent,
            false
        )
        val titleView = view.findViewById<TextView>(R.id.title)
        val descriptionView = view.findViewById<TextView>(R.id.description)

        return UnsupportedSectionViewHolder(view, titleView, descriptionView)
    }

    private fun createAddonViewHolder(parent: ViewGroup): AddonViewHolder {
        val context = parent.context
        val inflater = LayoutInflater.from(context)
        val view = inflater.inflate(R.layout.mozac_feature_addons_item, parent, false)
        val iconView = view.findViewById<ImageView>(R.id.add_on_icon)
        val titleView = view.findViewById<TextView>(R.id.add_on_name)
        val summaryView = view.findViewById<TextView>(R.id.add_on_description)
        val ratingView = view.findViewById<RatingBar>(R.id.rating)
        val ratingAccessibleView = view.findViewById<TextView>(R.id.rating_accessibility)
        val userCountView = view.findViewById<TextView>(R.id.users_count)
        val addButton = view.findViewById<ImageView>(R.id.add_button)
        val allowedInPrivateBrowsingLabel = view.findViewById<ImageView>(R.id.allowed_in_private_browsing_label)
        return AddonViewHolder(
            view,
            iconView,
            titleView,
            summaryView,
            ratingView,
            ratingAccessibleView,
            userCountView,
            addButton,
            allowedInPrivateBrowsingLabel
        )
    }

    override fun getItemViewType(position: Int): Int {
        return when (getItem(position)) {
            is Addon -> VIEW_HOLDER_TYPE_ADDON
            is Section -> VIEW_HOLDER_TYPE_SECTION
            is NotYetSupportedSection -> VIEW_HOLDER_TYPE_NOT_YET_SUPPORTED_SECTION
            else -> throw IllegalArgumentException("items[position] has unrecognized type")
        }
    }

    override fun onBindViewHolder(holder: CustomViewHolder, position: Int) {
        val item = getItem(position)

        when (holder) {
            is SectionViewHolder -> bindSection(holder, item as Section, position)
            is AddonViewHolder -> bindAddon(holder, item as Addon)
            is UnsupportedSectionViewHolder -> bindNotYetSupportedSection(
                holder,
                item as NotYetSupportedSection
            )
        }
    }

    @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
    internal fun bindSection(holder: SectionViewHolder, section: Section, position: Int) {
        holder.titleView.setText(section.title)

        style?.let {
            holder.divider.isVisible = it.visibleDividers && position != 0
            it.maybeSetSectionsTextColor(holder.titleView)
            it.maybeSetSectionsTypeFace(holder.titleView)
            it.maybeSetSectionsDividerStyle(holder.divider)
        }
    }

    @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
    internal fun bindNotYetSupportedSection(
        holder: UnsupportedSectionViewHolder,
        section: NotYetSupportedSection
    ) {
        val unsupportedAddons = addonsMap.values.filter { it.inUnsupportedSection() }
        val context = holder.itemView.context
        holder.titleView.setText(section.title)
        holder.descriptionView.text =
            if (unsupportedAddons.size == 1) {
                context.getString(R.string.mozac_feature_addons_unsupported_caption)
            } else {
                context.getString(
                    R.string.mozac_feature_addons_unsupported_caption_plural,
                    unsupportedAddons.size.toString()
                )
            }

        holder.itemView.setOnClickListener {
            addonsManagerDelegate.onNotYetSupportedSectionClicked(unsupportedAddons)
        }
    }

    @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
    internal fun bindAddon(holder: AddonViewHolder, addon: Addon) {
        val context = holder.itemView.context
        addon.rating?.let {
            val userCount = context.getString(R.string.mozac_feature_addons_user_rating_count_2)
            val ratingContentDescription =
                String.format(
                    context.getString(R.string.mozac_feature_addons_rating_content_description),
                    it.average
                )
            holder.ratingView.contentDescription = ratingContentDescription
            // Android RatingBar is not very accessibility-friendly, we will use non visible TextView
            // for contentDescription for the TalkBack feature
            holder.ratingAccessibleView.text = ratingContentDescription
            holder.ratingView.rating = it.average
            holder.userCountView.text = String.format(userCount, getFormattedAmount(it.reviews))
        }

        holder.titleView.text =
            if (addon.translatableName.isNotEmpty()) {
                addon.translateName(context)
            } else {
                addon.id
            }

        if (addon.translatableSummary.isNotEmpty()) {
            holder.summaryView.text = addon.translateSummary(context)
        } else {
            holder.summaryView.visibility = View.GONE
        }

        holder.itemView.tag = addon
        holder.itemView.setOnClickListener {
            addonsManagerDelegate.onAddonItemClicked(addon)
        }

        holder.addButton.isVisible = !addon.isInstalled()
        holder.addButton.setOnClickListener {
            if (!addon.isInstalled()) {
                addonsManagerDelegate.onInstallAddonButtonClicked(addon)
            }
        }

        holder.allowedInPrivateBrowsingLabel.isVisible = addon.isAllowedInPrivateBrowsing()
        style?.maybeSetPrivateBrowsingLabelDrawale(holder.allowedInPrivateBrowsingLabel)

        fetchIcon(addon, holder.iconView)
        style?.maybeSetAddonNameTextColor(holder.titleView)
        style?.maybeSetAddonSummaryTextColor(holder.summaryView)
    }

    @Suppress("MagicNumber")
    @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
    internal fun fetchIcon(addon: Addon, iconView: ImageView, scope: CoroutineScope = this.scope): Job {
        return scope.launch {
            try {
                // We calculate how much time takes to fetch an icon,
                // if takes less than a second, we assume it comes
                // from a cache and we don't show any transition animation.
                val startTime = System.currentTimeMillis()
                val iconBitmap = addonCollectionProvider.getAddonIconBitmap(addon)
                val timeToFetch: Double = (System.currentTimeMillis() - startTime) / 1000.0
                val isFromCache = timeToFetch < 1
                if (iconBitmap != null) {
                    scope.launch(Main) {
                        if (isFromCache) {
                            iconView.setImageDrawable(BitmapDrawable(iconView.resources, iconBitmap))
                        } else {
                            setWithCrossFadeAnimation(iconView, iconBitmap)
                        }
                    }
                } else if (addon.installedState?.icon != null) {
                    scope.launch(Main) {
                        iconView.setImageDrawable(BitmapDrawable(iconView.resources, addon.installedState.icon))
                    }
                }
            } catch (e: IOException) {
                scope.launch(Main) {
                    val context = iconView.context
                    val att = context.theme.resolveAttribute(android.R.attr.textColorPrimary)
                    iconView.setColorFilter(ContextCompat.getColor(context, att))
                    iconView.setImageDrawable(
                        ContextCompat.getDrawable(context, R.drawable.mozac_ic_extensions))
                }
                logger.error("Attempt to fetch the ${addon.id} icon failed", e)
            }
        }
    }

    @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
    @Suppress("ComplexMethod")
    internal fun createListWithSections(addons: List<Addon>, excludedAddonIDs: List<String> = emptyList()): List<Any> {
        val itemsWithSections = ArrayList<Any>()
        val installedAddons = ArrayList<Addon>()
        val recommendedAddons = ArrayList<Addon>()
        val disabledAddons = ArrayList<Addon>()
        val unsupportedAddons = ArrayList<Addon>()

        addons.forEach { addon ->
            when {
                addon.inUnsupportedSection() -> unsupportedAddons.add(addon)
                addon.inRecommendedSection() -> recommendedAddons.add(addon)
                addon.inInstalledSection() -> installedAddons.add(addon)
                addon.inDisabledSection() -> disabledAddons.add(addon)
            }
        }

        // Add installed section and addons if available
        if (installedAddons.isNotEmpty()) {
            itemsWithSections.add(Section(R.string.mozac_feature_addons_enabled, false))
            itemsWithSections.addAll(installedAddons)
        }

        // Add disabled section and addons if available
        if (disabledAddons.isNotEmpty()) {
            itemsWithSections.add(Section(R.string.mozac_feature_addons_disabled_section, true))
            itemsWithSections.addAll(disabledAddons)
        }

        // Add recommended section and addons if available
        if (recommendedAddons.isNotEmpty()) {
            itemsWithSections.add(Section(R.string.mozac_feature_addons_recommended_section, true))
            val filteredRecommendedAddons = recommendedAddons.filter {
                it.id !in excludedAddonIDs
            }
            itemsWithSections.addAll(filteredRecommendedAddons)
        }

        // Add unsupported section
        if (unsupportedAddons.isNotEmpty()) {
            itemsWithSections.add(NotYetSupportedSection(R.string.mozac_feature_addons_unavailable_section))
        }

        return itemsWithSections
    }

    @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
    internal data class Section(@StringRes val title: Int, val visibleDivider: Boolean = true)

    @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
    internal data class NotYetSupportedSection(@StringRes val title: Int)

    /**
     * Allows to customize how items should look like.
     */
    data class Style(
        @ColorRes
        val sectionsTextColor: Int? = null,
        @ColorRes
        val addonNameTextColor: Int? = null,
        @ColorRes
        val addonSummaryTextColor: Int? = null,
        val sectionsTypeFace: Typeface? = null,
        @DrawableRes
        val addonAllowPrivateBrowsingLabelDrawableRes: Int? = null,
        val visibleDividers: Boolean = true,
        @ColorRes
        val dividerColor: Int? = null,
        @DimenRes
        val dividerHeight: Int? = null
    ) {
        internal fun maybeSetSectionsTextColor(textView: TextView) {
            sectionsTextColor?.let {
                val color = ContextCompat.getColor(textView.context, it)
                textView.setTextColor(color)
            }
        }

        internal fun maybeSetSectionsTypeFace(textView: TextView) {
            sectionsTypeFace?.let {
                textView.typeface = it
            }
        }

        internal fun maybeSetAddonNameTextColor(textView: TextView) {
            addonNameTextColor?.let {
                val color = ContextCompat.getColor(textView.context, it)
                textView.setTextColor(color)
            }
        }

        internal fun maybeSetAddonSummaryTextColor(textView: TextView) {
            addonSummaryTextColor?.let {
                val color = ContextCompat.getColor(textView.context, it)
                textView.setTextColor(color)
            }
        }

        internal fun maybeSetPrivateBrowsingLabelDrawale(imageView: ImageView) {
            addonAllowPrivateBrowsingLabelDrawableRes?.let {
                imageView.setImageDrawable(ContextCompat.getDrawable(imageView.context, it))
            }
        }

        internal fun maybeSetSectionsDividerStyle(divider: View) {
            dividerColor?.let {
                divider.setBackgroundColor(it)
            }
            dividerHeight?.let {
                divider.layoutParams.height = divider.context.resources.getDimensionPixelOffset(it)
            }
        }
    }

    /**
     * Update the portion of the list that contains the provided [addon].
     * @property addon The add-on to be updated.
     */
    fun updateAddon(addon: Addon) {
        addonsMap[addon.id] = addon
        submitList(createListWithSections(addonsMap.values.toList(), excludedAddonIDs))
    }

    /**
     * Updates only the portion of the list that changes between the current list and the new provided [addons].
     * Be aware that updating a subset of the visible list is not supported, [addons] will replace
     * the current list, but only the add-ons that have been changed will be updated in the UI.
     * If you provide a subset it will replace the current list.
     * @property addons A list of add-on to replace the actual list.
     */
    fun updateAddons(addons: List<Addon>) {
        addonsMap = addons.associateBy({ it.id }, { it }).toMutableMap()
        submitList(createListWithSections(addons))
    }

    internal object DifferCallback : DiffUtil.ItemCallback<Any>() {
        override fun areItemsTheSame(oldItem: Any, newItem: Any): Boolean {
            return when {
                oldItem is Addon && newItem is Addon -> oldItem.id == newItem.id
                oldItem is Section && newItem is Section -> oldItem.title == newItem.title
                oldItem is NotYetSupportedSection && newItem is NotYetSupportedSection -> oldItem.title == newItem.title
                else -> false
            }
        }

        @SuppressLint("DiffUtilEquals")
        override fun areContentsTheSame(oldItem: Any, newItem: Any): Boolean {
            return oldItem == newItem
        }
    }

    internal fun setWithCrossFadeAnimation(image: ImageView, bitmap: Bitmap, durationMillis: Int = 1700) {
        with(image) {
            val bitmapDrawable = BitmapDrawable(context.resources, bitmap)
            val animation = TransitionDrawable(arrayOf(drawable, bitmapDrawable))
            animation.isCrossFadeEnabled = true
            setImageDrawable(animation)
            animation.startTransition(durationMillis)
        }
    }
}

private fun Addon.inUnsupportedSection() = isInstalled() && !isSupported()
private fun Addon.inRecommendedSection() = !isInstalled()
private fun Addon.inInstalledSection() = isInstalled() && isSupported() && isEnabled()
private fun Addon.inDisabledSection() = isInstalled() && isSupported() && !isEnabled()
