//
//  PDFConvertObject.swift
//  PDF Reader Pro
//
//  Created by liujiajie on 2023/11/17.
//

import Foundation

@objc(PDFConvertObjectDelegate)
protocol PDFConvertObjectDelegate: AnyObject {
    @objc optional func PDFConvertObjectDidStartConversion(_ converter: PDFConvertObject, error: Error?)
    @objc optional func PDFConvertObjectDidEndConversion(_ converter: PDFConvertObject, error: Error?)
    @objc optional func PDFConvertObjectDidPdfPage(_ converter: PDFConvertObject, didPDFPageIndexA: Int, didPageCountA: Int)
}

class PDFConvertObject: NSObject {
    var delegate: PDFConvertObjectDelegate?
    var document: CPDFDocument?
    lazy var suffix: Int = {
        if suffix == 0 {
            var suf = self.document?.pageCount
            while suf ?? 0 > 10 {
                suf! /= 10
                suffix += 1
            }
            suffix += 1
        }
        return suffix
    }()
    
    override init() {
        super.init()
        suffix = 0
    }
    
    func stopConversionIfNeeded() {
        self.document?.cancelExtractImage()
    }
    func extractResourcesFromPDF(at pdfPathA: String, pdfPassword pdfPasswordA: String?, selectIndexSet indexSet: IndexSet, destDocPath destDocPathA: String, moreOptions moreOptionsA: [AnyHashable: Any]?) {
        self.document = CPDFDocument(url: URL(fileURLWithPath: pdfPathA))
        if pdfPasswordA?.count ?? 0 > 0 {
            self.document?.unlock(withPassword: pdfPasswordA)
        }
        self.document?.extractImage(fromPages: indexSet, toPath: destDocPathA) { (pageIndex, imageIndex, index) -> String? in
            let fileName = self.document?.documentURL.deletingPathExtension().lastPathComponent
            let imageName = String(format: "%@_Page%ld_%@", fileName ?? "",pageIndex+1,self.imageNumberSuffix(imageIndex+1))
            return imageName
        }
        
        self.delegate?.PDFConvertObjectDidEndConversion?(self, error: nil)
    }
    func imageNumberSuffix(_ imageIndex: Int) -> String {
        let indexString = String(format: "%d", imageIndex)
        var suffixString = ""
        if suffix > indexString.count {
            for _ in 0..<(suffix - indexString.count) {
                suffixString = "(suffixString)0"
            }
            suffixString = "(suffixString)(indexString)"
            return suffixString
        }
        suffixString = indexString
        return suffixString
    }
}