//
//  KMFileThumbManager.swift
//  PDF Reader Pro
//
//  Created by Niehaoyu on 2024/11/22.
//

import Cocoa
import CryptoKit

class KMFileThumbManager: NSObject {
    
    let thumbFolderPath = NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.applicationSupportDirectory, FileManager.SearchPathDomainMask.userDomainMask, true).last?.stringByAppendingPathComponent(Bundle.main.bundleIdentifier!).stringByAppendingPathComponent("thumb")
    
    @objc public static let manager = KMFileThumbManager()
    
    private var iconSize: CGSize = CGSizeMake(126*3, 168*3)
    
    override init() {
        super.init()
        
        if (!FileManager.default.fileExists(atPath: thumbFolderPath!)) {
            try?FileManager.default.createDirectory(atPath: thumbFolderPath!, withIntermediateDirectories: true, attributes: nil)
        }
        
        refreshData()
    }
    
    private func refreshData() {
        let urls: Array<URL> = NSDocumentController.shared.recentDocumentURLs
        
        var fileNames: [String] = []
        for url in urls {
            let filePath = url.path
            let fileName = filePath.getLastComponentDeleteExtension
            
            let resultPath = thumbFolderPath?.stringByAppendingPathComponent((fileName + ".png"))
            if (!FileManager.default.fileExists(atPath: resultPath!)) {
                updateFile(url, iconSize)
            }
            fileNames.append((fileName + ".png"))
        }
        
        if let contents = try?FileManager.default.contentsOfDirectory(atPath: thumbFolderPath!) {
            for name in contents {
                if name != ".DS_Store" {
                    if let index = fileNames.firstIndex(of: name) {
                        
                    } else {
                        if let path = thumbFolderPath?.stringByAppendingPathComponent(name) {
                            try?FileManager.default.removeItem(atPath: path)
                        }
                    }
                }
            }
        }
    }
    
    private func generateThumbnail(for pdfURL: URL, _ size: NSSize) -> NSImage? {
        guard let pdfDocument = CGPDFDocument(pdfURL as CFURL),
              let pdfPage = pdfDocument.page(at: 1) else {
            
            return nil
        }
        
        let pageRect = pdfPage.getBoxRect(.mediaBox)
        
        // 创建图形上下文
        let bitsPerComponent = 8
        let bitmapInfo = CGImageAlphaInfo.premultipliedLast.rawValue
        let context = CGContext(data: nil, width: Int(size.width), height: Int(size.height), bitsPerComponent: bitsPerComponent, bytesPerRow: 0, space: CGColorSpaceCreateDeviceRGB(), bitmapInfo: bitmapInfo)
        
        // 绘制PDF页面
        //        context?.saveGState()
        //        context?.translateBy(x: 0, y: size.height)
        //        context?.scaleBy(x: 1.0, y: -1.0) // 反转坐标系
        context?.scaleBy(x: size.width / pageRect.width, y: size.height / pageRect.height) // 缩放
        context?.drawPDFPage(pdfPage)
        context?.restoreGState()
        
        // 创建NSImage
        if let cgImage = context?.makeImage() {
            return NSImage(cgImage: cgImage, size: NSSize(width: size.width, height: size.height))
        }
        return nil
    }
    
    public func updateFile(_ fileURL: URL, _ iconSize: CGSize) {
        let filePath = fileURL.path
        let fileName = filePath.getLastComponentDeleteExtension
        
        if let resultPath: String = thumbFolderPath?.stringByAppendingPathComponent((fileName + ".png")) {
            if let image = generateThumbnail(for: fileURL, iconSize) {
                guard let data = image.tiffRepresentation else {
                    return
                }
                let imageRep = NSBitmapImageRep(data: data)
                imageRep?.size = image.size
                if let imageData = imageRep?.representation(using: .png, properties: [:]) {
                    try?imageData.write(to: URL(fileURLWithPath: resultPath))
                }
            }
        }
    }
    
    public func getFileThumb(_ fileURL: URL) -> NSImage? {
        let filePath = fileURL.path
        let fileName = filePath.getLastComponentDeleteExtension
        
        if let resultPath: String = thumbFolderPath?.stringByAppendingPathComponent((fileName + ".png")) {
            return NSImage(contentsOf: URL(fileURLWithPath: resultPath))
        }
        return nil
    } 
    
    
}