mihon/app/src/main/java/eu/kanade/tachiyomi/widget/ExtendedNavigationView.kt

package eu.kanade.tachiyomi.widget

import android.content.Context
import android.graphics.drawable.Drawable
import android.support.annotation.CallSuper
import android.support.graphics.drawable.VectorDrawableCompat
import android.support.v4.content.ContextCompat
import android.support.v7.widget.RecyclerView
import android.util.AttributeSet
import android.view.View
import android.view.ViewGroup
import eu.kanade.tachiyomi.R
import eu.kanade.tachiyomi.util.getResourceColor

/**
 * An alternative implementation of [android.support.design.widget.NavigationView], without menu
 * inflation and allowing customizable items (multiple selections, custom views, etc).
 */
open class ExtendedNavigationView @JvmOverloads constructor(
        context: Context,
        attrs: AttributeSet? = null,
        defStyleAttr: Int = 0)
    : SimpleNavigationView(context, attrs, defStyleAttr) {

    /**
     * Every item of the nav view. Generic items must belong to this list, custom items could be
     * implemented by an abstract class. If more customization is needed in the future, this can be
     * changed to an interface instead of sealed class.
     */
    sealed class Item {
        /**
         * A view separator.
         */
        class Separator(val paddingTop: Int = 0, val paddingBottom: Int = 0) : Item()

        /**
         * A header with a title.
         */
        class Header(val resTitle: Int) : Item()

        /**
         * A checkbox.
         */
        open class Checkbox(val resTitle: Int, var checked: Boolean = false) : Item()

        /**
         * A checkbox belonging to a group. The group must handle selections and restrictions.
         */
        class CheckboxGroup(resTitle: Int, override val group: Group, checked: Boolean = false)
            : Checkbox(resTitle, checked), GroupedItem

        /**
         * A radio belonging to a group (a sole radio makes no sense). The group must handle
         * selections and restrictions.
         */
        class Radio(val resTitle: Int, override val group: Group, var checked: Boolean = false)
            : Item(), GroupedItem

        /**
         * An item with which needs more than two states (selected/deselected).
         */
        abstract class MultiState(val resTitle: Int, var state: Int = 0) : Item() {

            /**
             * Returns the drawable associated to every possible each state.
             */
            abstract fun getStateDrawable(context: Context): Drawable?

            /**
             * Creates a vector tinted with the accent color.
             *
             * @param context any context.
             * @param resId the vector resource to load and tint
             */
            fun tintVector(context: Context, resId: Int): Drawable {
                return VectorDrawableCompat.create(context.resources, resId, context.theme)!!.apply {
                    setTint(context.getResourceColor(R.attr.colorAccent))
                }
            }
        }

        /**
         * An item with which needs more than two states (selected/deselected) belonging to a group.
         * The group must handle selections and restrictions.
         */
        abstract class MultiStateGroup(resTitle: Int, override val group: Group, state: Int = 0)
            : MultiState(resTitle, state), GroupedItem

        /**
         * A multistate item for sorting lists (unselected, ascending, descending).
         */
        class MultiSort(resId: Int, group: Group) : MultiStateGroup(resId, group) {

            companion object {
                const val SORT_NONE = 0
                const val SORT_ASC = 1
                const val SORT_DESC = 2
            }

            override fun getStateDrawable(context: Context): Drawable? {
                return when (state) {
                    SORT_ASC -> tintVector(context, R.drawable.ic_arrow_up_white_32dp)
                    SORT_DESC -> tintVector(context, R.drawable.ic_arrow_down_white_32dp)
                    SORT_NONE -> ContextCompat.getDrawable(context, R.drawable.empty_drawable_32dp)
                    else -> null
                }
            }

        }
    }

    /**
     * Interface for an item belonging to a group.
     */
    interface GroupedItem {
        val group: Group
    }

    /**
     * A group containing a list of items.
     */
    interface Group {

        /**
         * An optional header for the group, typically a [Item.Header].
         */
        val header: Item?

        /**
         * An optional footer for the group, typically a [Item.Separator].
         */
        val footer: Item?

        /**
         * The items of the group, excluding header and footer.
         */
        val items: List<Item>

        /**
         * Creates all the elements of this group. Implementations can override this method for more
         * customization.
         */
        fun createItems() = (mutableListOf<Item>() + header + items + footer).filterNotNull()

        /**
         * Called after creating the list of items. Implementations should load the current values
         * into the models.
         */
        fun initModels()

        /**
         * Called when an item of this group is clicked. The group is responsible for all the
         * selections of its items.
         */
        fun onItemClicked(item: Item)

    }

    /**
     * Base adapter for the navigation view. It knows how to create and render every subclass of
     * [Item].
     */
    abstract inner class Adapter(private val items: List<Item>) : RecyclerView.Adapter<Holder>() {

        private val onClick = View.OnClickListener {
            val pos = recycler.getChildAdapterPosition(it)
            val item = items[pos]
            onItemClicked(item)
        }

        fun notifyItemChanged(item: Item) {
            val pos = items.indexOf(item)
            if (pos != -1) notifyItemChanged(pos)
        }

        override fun getItemCount(): Int {
            return items.size
        }

        @CallSuper
        override fun getItemViewType(position: Int): Int {
            val item = items[position]
            return when (item) {
                is Item.Header -> VIEW_TYPE_HEADER
                is Item.Separator -> VIEW_TYPE_SEPARATOR
                is Item.Radio -> VIEW_TYPE_RADIO
                is Item.Checkbox -> VIEW_TYPE_CHECKBOX
                is Item.MultiState -> VIEW_TYPE_MULTISTATE
            }
        }

        @CallSuper
        override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): Holder {
            return when (viewType) {
                VIEW_TYPE_HEADER -> HeaderHolder(parent)
                VIEW_TYPE_SEPARATOR -> SeparatorHolder(parent)
                VIEW_TYPE_RADIO -> RadioHolder(parent, onClick)
                VIEW_TYPE_CHECKBOX -> CheckboxHolder(parent, onClick)
                VIEW_TYPE_MULTISTATE -> MultiStateHolder(parent, onClick)
                else -> throw Exception("Unknown view type")
            }
        }

        @CallSuper
        override fun onBindViewHolder(holder: Holder, position: Int) {
            when (holder) {
                is HeaderHolder -> {
                    val item = items[position] as Item.Header
                    holder.title.setText(item.resTitle)
                }
                is SeparatorHolder -> {
                    val view = holder.itemView
                    val item = items[position] as Item.Separator
                    view.setPadding(0, item.paddingTop, 0, item.paddingBottom)
                }
                is RadioHolder -> {
                    val item = items[position] as Item.Radio
                    holder.radio.setText(item.resTitle)
                    holder.radio.isChecked = item.checked
                }
                is CheckboxHolder -> {
                    val item = items[position] as Item.CheckboxGroup
                    holder.check.setText(item.resTitle)
                    holder.check.isChecked = item.checked
                }
                is MultiStateHolder -> {
                    val item = items[position] as Item.MultiStateGroup
                    val drawable = item.getStateDrawable(context)
                    holder.text.setText(item.resTitle)
                    holder.text.setCompoundDrawablesWithIntrinsicBounds(drawable, null, null, null)
                }
            }
        }

        abstract fun onItemClicked(item: Item)

    }

}