/*
 * 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.content.pm.PackageManager
import android.content.pm.PermissionInfo
import android.os.Build
import android.os.UserHandle
import com.android.permissioncontroller.PermissionControllerApplication
import com.android.permissioncontroller.permission.utils.PermissionMapping
import kotlinx.coroutines.Job

/**
 * LiveData with a map representing the runtime permissions a group requests and all of the
 * installed, non-runtime, normal protection permissions. Key is the group name or
 * NON_RUNTIME_NORMAL_PERMS, value is the requested runtime permissions in that group (or all
 * installed non-runtime normal protection permissions, for NON_RUNTME_NORMAL_PERMS).
 *
 * @param app The current Application
 * @param packageName The name of the package this LiveData will watch for mode changes for
 * @param user The user for whom the packageInfo will be defined
 */
class PackagePermissionsLiveData private constructor(
    private val app: Application,
    packageName: String,
    user: UserHandle
) : SmartAsyncMediatorLiveData<Map<String, List<String>>?>() {

    private val packageInfoLiveData = LightPackageInfoLiveData[packageName, user]

    init {
        addSource(packageInfoLiveData) {
            if (packageInfoLiveData.isInitialized && packageInfoLiveData.value == null) {
                invalidateSingle(packageName to user)
                value = null
                return@addSource
            }
            update()
        }
    }

    override suspend fun loadDataAndPostValue(job: Job) {
        val packageInfo = packageInfoLiveData.value ?: return
        val permissionMap = mutableMapOf<String, MutableList<String>>()
        for (permName in packageInfo.requestedPermissions) {
            var groupName = PermissionMapping.getGroupOfPlatformPermission(permName)
            if (groupName == null) {
                val permInfo = try {
                    app.packageManager.getPermissionInfo(permName, 0)
                } catch (e: PackageManager.NameNotFoundException) {
                    continue
                }

                if (permInfo.flags and PermissionInfo.FLAG_INSTALLED == 0 ||
                    permInfo.flags and PermissionInfo.FLAG_REMOVED != 0) {
                    continue
                }

                if (packageInfo.isInstantApp && permInfo.protectionFlags and
                    PermissionInfo.PROTECTION_FLAG_INSTANT == 0) {
                    continue
                }

                if (packageInfo.targetSdkVersion < Build.VERSION_CODES.M &&
                    (permInfo.protectionFlags and PermissionInfo.PROTECTION_FLAG_RUNTIME_ONLY) !=
                    0) {
                    continue
                }

                // If this permission is a non-runtime, normal permission, add it to the
                // "non runtime" group
                if (permInfo.protection != PermissionInfo.PROTECTION_DANGEROUS) {
                    if (permInfo.protection == PermissionInfo.PROTECTION_NORMAL) {
                        val otherPermsList =
                            permissionMap.getOrPut(NON_RUNTIME_NORMAL_PERMS) { mutableListOf() }
                        otherPermsList.add(permInfo.name)
                    }
                    continue
                }

                groupName = PermissionMapping.getGroupOfPermission(permInfo) ?: permName
            }

            permissionMap.getOrPut(groupName) { mutableListOf() }.add(permName)
        }

        postValue(permissionMap)
    }

    /**
     * Repository for PackagePermissionsLiveData objects
     * <p> Key value is a string package name and userHandle, value is its corresponding LiveData.
     */
    companion object : DataRepositoryForPackage<Pair<String, UserHandle>,
        PackagePermissionsLiveData>() {
        override fun newValue(key: Pair<String, UserHandle>):
            PackagePermissionsLiveData {
            return PackagePermissionsLiveData(PermissionControllerApplication.get(), key.first,
                key.second)
        }

        const val NON_RUNTIME_NORMAL_PERMS = "nonRuntimeNormalPerms"
    }
}