//
//  KMThumbnailCache.swift
//  PDF Reader Pro
//
//  Created by lizhe on 2024/8/9.
//

class KMThumbnailCache: NSObject {
    static let shared = KMThumbnailCache()
    
    private let maxCacheSize = 50
    private var thumbnails: [Int: NSImage] = [:]
    private var order: [Int] = [] // 记录插入顺序的数组

    func addThumbnail(id: Int, image: NSImage) {
        if thumbnails.count >= maxCacheSize {
            if let oldestID = order.first {
                thumbnails.removeValue(forKey: oldestID)
                order.removeFirst()
            }
        }
        
        thumbnails[id] = image
        order.append(id)
    }
    
    func thumbnail(for id: Int) -> NSImage? {
        return thumbnails[id]
    }
    
    func removeThumbnail(for id: Int) {
        if let index = order.firstIndex(of: id) {
            thumbnails.removeValue(forKey: id)
            order.remove(at: index)
        } else {
            print("ID not found")
        }
    }
    
    func clearCache() {
        thumbnails.removeAll()
        order.removeAll()
    }
}