//
//  KMConvertPDFManager.swift
//  PDF Master
//
//  Created by wanjun on 2022/12/19.
//

import Cocoa

class KMConvertPDFPage: CPDFPage {
    var url: URL?
    
    override func draw(with box: CPDFDisplayBox, to context: CGContext!) {
        super.draw(with: box, to: context)
        if (context != nil) {
            NSGraphicsContext.current = NSGraphicsContext.init(cgContext: context, flipped: false)
        }
        drawImageTocontext(context)
    }
    
    func drawImageTocontext(_ context: CGContext) -> Void {
        let blankA4Size = CGSize(width: 595, height: 842)
        let imageCIImage = CIImage(data: try! Data(contentsOf: url!))
        let imagesize = imageCIImage?.extent.size
        var rect = NSZeroRect
        let image = NSImage.init(contentsOfFile: url!.path)
        if imagesize!.width <= blankA4Size.width && imagesize!.height <= blankA4Size.height {
            rect = CGRect(x: (blankA4Size.width-imagesize!.width)/2, y: (blankA4Size.height-imagesize!.height)/2, width: imagesize!.width, height: imagesize!.height)
        } else {
            let scanl = min(blankA4Size.width/imagesize!.width, blankA4Size.height/imagesize!.height)
            rect = CGRect(x: 0, y: 0, width: imagesize!.width * scanl, height: imagesize!.height * scanl)
        }
        image?.draw(in: rect, from: NSZeroRect, operation: .sourceOver, fraction: 1.0)
    }
}

class KMConvertPDFManager: NSObject {
    
    class func convertImages(_ imagesPaths: [URL], savePath: String, completionHandler complet: @escaping (_ success: Bool, _ errorDic: [String: Any]) -> Void) -> Void {
        DispatchQueue.global().async {
            let pdf = CPDFDocument.init()
            let blankA4Size = CGSize(width: 595, height: 842)
            for url in imagesPaths {
                let page = KMConvertPDFPage.init()
                page.url = url
                let imageCIImage = CIImage(data: try! Data(contentsOf: url))
                let size = imageCIImage?.extent.size
                var contextSize = NSZeroSize
                
                if size!.width <= blankA4Size.width && size!.height <= blankA4Size.height {
                    contextSize = blankA4Size
                } else {
                    let scanl = min(blankA4Size.width/size!.width, blankA4Size.height/size!.height)
                    contextSize = CGSize(width: size!.width * scanl, height: size!.height * scanl)
                }
                
                page.setBounds(CGRect(x: 0, y: 0, width: contextSize.width, height: contextSize.height), for: .mediaBox)
                pdf?.insertPageObject(page, at: pdf!.pageCount)
            }
            
            DispatchQueue.main.async {
                let isSucceed = pdf?.write(toFile: savePath)
                complet(isSucceed!, [:])
            }
        }
    }

}