//
//  KMImageOptimization.swift
//  PDF Reader Pro
//
//  Created by lizhe on 2023/5/25.
//

import AppKit
import CoreGraphics
import CoreImage

class KMImageOptimization: NSObject {
    static func compressImageLosslessly(image: NSImage, targetSize: CGSize, maxSizeInBytes: Int, targetCompression: CGFloat) -> Data? {
        guard let cgImage = image.cgImage(forProposedRect: nil, context: nil, hints: nil) else {
            return nil
        }
        
        //宽高自适应
        let newSize: CGSize
        let widthRatio = targetSize.width / image.size.width
        let heightRatio = targetSize.height / image.size.height
        
        if widthRatio > heightRatio {
            newSize = CGSize(width: targetSize.height * image.size.width / image.size.height, height: targetSize.height)
        } else {
            newSize = CGSize(width: targetSize.width, height: targetSize.width * image.size.height / image.size.width)
        }
        
        let options: [CFString: Any] = [
            kCGImageSourceThumbnailMaxPixelSize: max(newSize.width, newSize.height),
            kCGImageSourceCreateThumbnailFromImageAlways: true,
            kCGImageDestinationLossyCompressionQuality: 1.0
        ]
        
        guard var imageData = CFDataCreateMutable(nil, 0) else {
            return nil
        }
        
        guard let destination = CGImageDestinationCreateWithData(imageData, kUTTypeJPEG, 1, nil) else {
            return nil
        }
        
        CGImageDestinationAddImage(destination, cgImage, options as CFDictionary)
        CGImageDestinationFinalize(destination)
        
        var dataSize = CFDataGetLength(imageData)
        let targetSizeInBytes = Int(CGFloat(maxSizeInBytes) * targetCompression)
        
        if dataSize <= targetSizeInBytes {
            return imageData as Data
        }
        
        var compressedData: Data?
        
        let optionsLow: [CFString: Any] = [
            kCGImageSourceThumbnailMaxPixelSize: max(newSize.width, newSize.height) / 2,
            kCGImageSourceCreateThumbnailFromImageAlways: true,
            kCGImageDestinationLossyCompressionQuality: targetCompression
        ]
        
        let optionsHigh: [CFString: Any] = [
            kCGImageSourceThumbnailMaxPixelSize: max(newSize.width, newSize.height),
            kCGImageSourceCreateThumbnailFromImageAlways: true,
            kCGImageDestinationLossyCompressionQuality: targetCompression
        ]
        
        while compressedData == nil {
            autoreleasepool {
                if targetSizeInBytes > 0 {
                    if dataSize <= targetSizeInBytes {
                        compressedData = imageData as Data
                    } else {
                        let resizedImageData = NSMutableData()
                        
                        guard let resizedDestination = CGImageDestinationCreateWithData(resizedImageData as CFMutableData, kUTTypeJPEG, 1, nil) else {
                            return
                        }
                        
                        let bitmapInfo = CGImageAlphaInfo.premultipliedLast.rawValue
                        let contextBounds = CGRect(origin: .zero, size: newSize)
                        
                        if let context = CGContext(data: nil, width: Int(newSize.width), height: Int(newSize.height), bitsPerComponent: 8, bytesPerRow: 0, space: CGColorSpaceCreateDeviceRGB(), bitmapInfo: bitmapInfo) {
                            context.interpolationQuality = .high
                            context.draw(cgImage, in: contextBounds)
                            let resizedCGImage = context.makeImage()
                            
                            if let resizedCGImage = resizedCGImage {
                                CGImageDestinationAddImage(resizedDestination, resizedCGImage, optionsLow as CFDictionary)
                                CGImageDestinationFinalize(resizedDestination)
                                
                                imageData = resizedImageData
                                dataSize = CFDataGetLength(imageData)
                            } else {
                                compressedData = imageData as Data
                            }
                        }
                    }
                } else {
                    compressedData = imageData as Data
                }
            }
        }
        
        return compressedData
    }
    
    static func resizeImage(_ image: NSImage, toSize newSize: NSSize) -> Data? {
        let resizedImage = NSImage(size: newSize)
        
        resizedImage.lockFocus()
        NSGraphicsContext.current?.imageInterpolation = .high
        
        image.draw(in: NSRect(x: 0, y: 0, width: newSize.width, height: newSize.height), from: NSRect.zero, operation: .copy, fraction: 1.0)
        
        resizedImage.unlockFocus()
        
        guard let imageData = resizedImage.tiffRepresentation,
              let bitmapImage = NSBitmapImageRep(data: imageData),
              let compressedData = bitmapImage.representation(using: .png, properties: [:]) else {
            return nil
        }
        
        return compressedData
    }
    
    static func needCompressImageLosslessly(image: NSImage, targetSize: CGSize, maxSizeInBytes: Int, targetCompression: CGFloat) -> String {
        let kFilePath: NSString = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first!.path + "KMImageOptimizationCache" as NSString
        let string: NSString = (kFilePath as String) + "/" + "optimization.png" as NSString
        if (!FileManager.default.fileExists(atPath: string.deletingLastPathComponent as String)) {
            try?FileManager.default.createDirectory(atPath: string.deletingLastPathComponent as String, withIntermediateDirectories: true, attributes: nil)
        }
        
        if (!FileManager.default.fileExists(atPath: string as String)) {
            FileManager.default.createFile(atPath: string as String, contents: nil)
        }
        
        if let compressedData = KMImageOptimization.compressImageLosslessly(image: image, targetSize: targetSize, maxSizeInBytes: maxSizeInBytes, targetCompression: targetCompression) {
            let saveURL = URL(fileURLWithPath: string as String)//URL(fileURLWithPath: "/path/to/save/compressed_image.png")
            do {
                try compressedData.write(to: saveURL)
                KMPrint("保存图像成功：\(string)")
            } catch {
                KMPrint("保存图像失败：\(error)")
            }
        }
        
        return string as String
    }
}