/*
 * Copyright 2019 New Vector Ltd
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package im.vector.riotredesign.features.home.room.list

import androidx.annotation.StringRes
import com.airbnb.epoxy.TypedEpoxyController
import im.vector.matrix.android.api.session.room.model.RoomSummary
import im.vector.riotredesign.core.resources.StringProvider

class RoomSummaryController(private val stringProvider: StringProvider
) : TypedEpoxyController<RoomListViewState>() {

    var callback: Callback? = null

    override fun buildModels(viewState: RoomListViewState) {
        val roomSummaries = viewState.asyncRooms()
        roomSummaries?.forEach { (category, summaries) ->
            if (summaries.isEmpty()) {
                return@forEach
            } else {
                val isExpanded = viewState.isCategoryExpanded(category)
                buildRoomCategory(viewState, summaries, category.titleRes, viewState.isCategoryExpanded(category)) {
                    callback?.onToggleRoomCategory(category)
                }
                if (isExpanded) {
                    buildRoomModels(summaries, viewState.visibleRoomId)
                }
            }
        }
    }

    private fun buildRoomCategory(viewState: RoomListViewState,
                                  summaries: List<RoomSummary>,
                                  @StringRes titleRes: Int,
                                  isExpanded: Boolean,
                                  mutateExpandedState: () -> Unit) {
        if (summaries.isEmpty()) {
            return
        }
        //TODO should add some business logic later
        val unreadCount = if (summaries.isEmpty()) {
            0
        } else {
            summaries.map { it.notificationCount }.reduce { acc, i -> acc + i }
        }
        val showHighlighted = summaries.any { it.highlightCount > 0 }
        roomCategoryItem {
            id(titleRes)
            title(stringProvider.getString(titleRes).toUpperCase())
            expanded(isExpanded)
            unreadCount(unreadCount)
            showHighlighted(showHighlighted)
            listener {
                mutateExpandedState()
                setData(viewState)
            }
        }
    }

    private fun buildRoomModels(summaries: List<RoomSummary>, selectedRoomId: String?) {
        summaries.forEach { roomSummary ->
            val unreadCount = roomSummary.notificationCount
            val showHighlighted = roomSummary.highlightCount > 0
            val isSelected = roomSummary.roomId == selectedRoomId

            roomSummaryItem {
                id(roomSummary.roomId)
                roomName(roomSummary.displayName)
                avatarUrl(roomSummary.avatarUrl)
                selected(isSelected)
                showHighlighted(showHighlighted)
                unreadCount(unreadCount)
                listener { callback?.onRoomSelected(roomSummary) }
            }
        }
    }

    interface Callback {
        fun onToggleRoomCategory(roomCategory: RoomCategory)
        fun onRoomSelected(room: RoomSummary)
    }

}