//
/*
Copyright 2023 Splunk Inc.

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.
*/

import Foundation
import System
import UIKit

internal class DeviceStats {
    class var batteryLevel: String {
        UIDevice.current.isBatteryMonitoringEnabled = true
        let level = abs(UIDevice.current.batteryLevel * 100)
        return "\(level)%"
    }
    class var freeDiskSpace: String {
        do {
            let systemAttributes = try FileManager.default.attributesOfFileSystem(forPath: NSHomeDirectory() as String)
            let maybeFreeSpace = (systemAttributes[FileAttributeKey.systemFreeSize] as? NSNumber)?.int64Value
            guard let freeSpace = maybeFreeSpace else {
                return "Unknown"
            }
            return ByteCountFormatter.string(fromByteCount: freeSpace, countStyle: .file)
        } catch {
            return "Unknown"
        }
    }
    // https://stackoverflow.com/questions/5012886/determining-the-available-amount-of-ram-on-an-ios-device/8540665#8540665
    class var freeMemory: String {
        var usedBytes: Float = 0
        let totalBytes = Float(ProcessInfo.processInfo.physicalMemory)
        var info = mach_task_basic_info()
        var count = mach_msg_type_number_t(MemoryLayout<mach_task_basic_info>.size) / 4
        let kerr: kern_return_t = withUnsafeMutablePointer(to: &info) {
            $0.withMemoryRebound(to: integer_t.self, capacity: 1) {
                task_info(
                        mach_task_self_,
                        task_flavor_t(MACH_TASK_BASIC_INFO),
                        $0,
                        &count
                )
            }
        }
        if kerr == KERN_SUCCESS {
            usedBytes = Float(info.resident_size)
        } else {
            return "Unknown"
        }
        let freeBytes = totalBytes - usedBytes
        return ByteCountFormatter.string(fromByteCount: Int64(freeBytes), countStyle: .memory)
    }

}