/*
 * Copyright (C) 2019 The Android Open Source Project
 *
 * 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 com.android.permissioncontroller.permission.data

import android.app.Application
import android.os.UserHandle
import androidx.lifecycle.LiveData
import com.android.permissioncontroller.permission.model.livedatatypes.AppPermGroupUiInfo
import com.android.permissioncontroller.permission.model.livedatatypes.PermGroupPackagesUiInfo

/**
 * A LiveData which tracks all app permission groups for a set of permission groups, either platform
 * or custom, as well as the UI information related to each app permission group, and the permission
 * group as a whole.
 *
 * @param app The current application
 */
class PermGroupsPackagesUiInfoLiveData(
    private val app: Application,
    groupNamesLiveData: LiveData<List<String>>
) : SmartUpdateMediatorLiveData<
    @kotlin.jvm.JvmSuppressWildcards Map<String, PermGroupPackagesUiInfo?>>() {

    /**
     * Map<permission group name, PermGroupUiLiveDatas>
     */
    private val permGroupPackagesLiveDatas = mutableMapOf<String,
        SinglePermGroupPackagesUiInfoLiveData>()
    private val allPackageData = mutableMapOf<String, PermGroupPackagesUiInfo?>()

    private lateinit var groupNames: List<String>

    init {
        addSource(groupNamesLiveData) {
            groupNames = it ?: emptyList()
            updateIfActive()
            getPermGroupPackageLiveDatas()
        }
    }

    private fun getPermGroupPackageLiveDatas() {
        val getLiveData = { groupName: String -> SinglePermGroupPackagesUiInfoLiveData[groupName] }
        setSourcesToDifference(groupNames, permGroupPackagesLiveDatas, getLiveData)
    }

    private fun getNonSystemTotal(uiInfo: Map<Pair<String, UserHandle>, AppPermGroupUiInfo>): Int {
        var shownNonSystem = 0
        for ((_, appPermGroup) in uiInfo) {
            if (appPermGroup.shouldShow && !appPermGroup.isSystem) {
                shownNonSystem++
            }
        }
        return shownNonSystem
    }

    private fun getNonSystemGranted(
        uiInfo: Map<Pair<String, UserHandle>, AppPermGroupUiInfo>
    ): Int {
        var granted = 0
        for ((_, appPermGroup) in uiInfo) {
            if (appPermGroup.shouldShow && !appPermGroup.isSystem &&
                appPermGroup.permGrantState != AppPermGroupUiInfo.PermGrantState.PERMS_DENIED &&
                appPermGroup.permGrantState != AppPermGroupUiInfo.PermGrantState.PERMS_ASK) {
                granted++
            }
        }
        return granted
    }

    override fun onUpdate() {
        /**
         * Only update when either-
         * We have a list of groups, and none have loaded their data, or
         * All packages have loaded their data
         */
        val haveAllLiveDatas = groupNames.all { permGroupPackagesLiveDatas.contains(it) }
        val allInitialized = permGroupPackagesLiveDatas.all { it.value.isInitialized }
        for (groupName in groupNames) {
            allPackageData[groupName] = if (haveAllLiveDatas && allInitialized) {
                permGroupPackagesLiveDatas[groupName]?.value?.let { uiInfo ->
                    PermGroupPackagesUiInfo(groupName,
                        getNonSystemTotal(uiInfo), getNonSystemGranted(uiInfo))
                }
            } else {
                null
            }
        }
        value = allPackageData.toMap()
    }
}