//
//  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()
         
        let tabClosingNoti = NSNotification.Name("CTTabClosingNotification")
        NotificationCenter.default.addObserver(self, selector: #selector(tabClosingNotification), name: tabClosingNoti, object: nil)

        refreshData()
    }
    
    func refreshData() {
        
        if let path = thumbFolderPath {
            try?FileManager.default.removeItem(atPath: path)
            
            if (!FileManager.default.fileExists(atPath: path)) {
                try?FileManager.default.createDirectory(atPath: path, withIntermediateDirectories: true, attributes: nil)
            }
        }
        
        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 = PDFDocument(url: pdfURL),
              let pdfPage = pdfDocument.page(at: 0) else {
            return nil
        }
        
        if pdfDocument.isLocked || pdfDocument.isEncrypted {
            return NSImage(named: "file_lock")
        }
        let pdfPageBounds = pdfPage.bounds(for: .mediaBox)
        let scale = min(size.width / pdfPageBounds.width, size.height / pdfPageBounds.height)
        
        let thumbnailSize = CGSize(width: pdfPageBounds.width * scale, height: pdfPageBounds.height * scale)
        let thumbnail = pdfPage.thumbnail(of: thumbnailSize, for: .mediaBox)
        
        return thumbnail
    }
    
    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
    } 
    
    @objc func tabClosingNotification(_ sender: Notification) {
        self.refreshData()
    }
    
}