ALLogger.swift

//
//  ALLogger.swift
//
//  Created by Antoine van der Lee on 21/06/16.
//  Copyright © 2016 Antoine van der Lee. All rights reserved.
//

import Foundation
import UIKit

public typealias DDLogLevel = ALLogLevel
public typealias DDASLLogger = ALASLLogger

public func DDLogVerbose(_ logText: @autoclosure () -> String, level: ALLogLevel? = nil){
    ALLogger.logVerbose(logText, level: level ?? .verbose)
}

public func DDLogInfo(_ logText: @autoclosure () -> String, level: ALLogLevel? = nil){
    ALLogger.logInfo(logText, level: level ?? .verbose)
}

public func DDLogDebug(_ logText: @autoclosure () -> String, level: ALLogLevel? = nil){
    ALLogger.logDebug(logText, level: level ?? .verbose)
}

public func DDLogWarn(_ logText: @autoclosure () -> String, level: ALLogLevel? = nil){
    ALLogger.logWarn(logText, level: level ?? .verbose)
}

public func DDLogError(_ logText: @autoclosure () -> String, level: ALLogLevel? = nil){
    ALLogger.logError(logText, level: level ?? .verbose)
}


public enum ALLogLevel : Int {
    case verbose = 0
    case info = 1
    case debug = 2
    case warning = 3
    case error = 4
}

extension ALLogLevel : Equatable { }


public func ==(lhs:ALLogLevel, rhs:ALLogLevel) -> Bool {
    return lhs.rawValue == rhs.rawValue
}

public func <=(lhs:ALLogLevel, rhs:ALLogLevel) -> Bool {
    return lhs.rawValue >= rhs.rawValue
}

public func >=(lhs:ALLogLevel, rhs:ALLogLevel) -> Bool {
    return lhs.rawValue <= rhs.rawValue
}


public struct ALLogMessage {
    let message: String
    let level: ALLogLevel
}

public final class ALLogger {
    
    public static let sharedInstance = ALLogger()
    
    private lazy var abstractLoggers = [ALAbstractLogger]()
    private static let defaultDebugLevel = ALLogLevel.verbose
    
    public func addLogger(_ logger:ALAbstractLogger){
        abstractLoggers.append(logger)
    }
    
    static func logVerbose(_ logText: @autoclosure () -> String, level: ALLogLevel = defaultDebugLevel){
        guard ALLogLevel.verbose <= level else { return }
        log(logText, level: level)
    }
    
    static func logInfo(_ logText: @autoclosure () -> String, level: ALLogLevel = defaultDebugLevel){
        guard ALLogLevel.info <= level else { return }
        log(logText, level: level)
    }
    
    static func logDebug(_ logText: @autoclosure () -> String, level: ALLogLevel = defaultDebugLevel){
        guard ALLogLevel.debug <= level else { return }
        log(logText, level: level)
    }
    
    static func logWarn(_ logText: @autoclosure () -> String, level: ALLogLevel = defaultDebugLevel){
        guard ALLogLevel.warning <= level else { return }
        log(logText, level: level)
    }
    
    static func logError(_ logText: @autoclosure () -> String, level: ALLogLevel = defaultDebugLevel){
        guard ALLogLevel.error <= level else { return }
        log(logText, level: level)
    }
    
    private static func log(_ logText: @autoclosure () -> String, level: ALLogLevel = defaultDebugLevel){
        let message = ALLogMessage(message: logText(), level: level)
        sharedInstance.abstractLoggers.forEach { $0.logMessage(message) }
    }
}

public protocol ALAbstractLogger {
    func logMessage(_ logMessage: ALLogMessage)
}

/**
 * This class provides a logger for the Apple System Log facility.
 *
 * As described in the "Getting Started" page,
 * the traditional NSLog() function directs its output to two places:
 *
 * - Apple System Log
 * - StdErr (if stderr is a TTY) so log statements show up in Xcode console
 *
 * To duplicate NSLog() functionality you can simply add this logger and a tty logger.
 * However, if you instead choose to use file logging (for faster performance),
 * you may choose to use a file logger and a tty logger.
 **/
public final class ALASLLogger : ALAbstractLogger {
    
    public var colorsEnabled:Bool = false
    
    public init(){}
    
    public func logMessage(_ logMessage: ALLogMessage){
        if colorsEnabled {
            ColorLog.log(logMessage.message, withColor: logMessage.level.colorValue.cgColor)
        } else {
            print("|>>> \(logMessage.message)")
        }
    }
}

private struct ColorLog {
    static let ESCAPE = "\u{001b}["
    static let RESET_FG = ESCAPE + "fg;" // Clear any foreground color
    static let RESET_BG = ESCAPE + "bg;" // Clear any background color
    static let RESET = ESCAPE + ";"   // Clear any foreground or background color
    
    static func log<T>(_ object: T, withColor color:CGColor){
        let components = color.components
        let red = (components?[0])! * 255
        let green = (components?[1])! * 255
        let blue = (components?[2])! * 255
        
        let printString = String(format: "\(ESCAPE)fg%.0f,%.0f,%.0f;\(object)\(RESET)", red, green, blue)
        print(printString)
    }
}

private extension ALLogLevel {
    var colorValue:UIColor {
        switch self {
        case .info:
            return UIColor.blue
        case .warning:
            return UIColor.orange
        case .error:
            return UIColor.red
        default:
            return UIColor.black
        }
    }
}