//
//  KMPDFThumbnialPageView.swift
//  PDF Master
//
//  Created by tangchao on 2022/11/24.
//

import Cocoa
import PDFKit

class KMPDFThumbnialPageLayer: CATiledLayer {
    var page: CPDFPage?
    
    override init() {
        super.init()
        
        self.initDefaultValue()
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        
        self.initDefaultValue()
    }
    
    public func initDefaultValue() {
        self.levelsOfDetail = 2
        self.levelsOfDetailBias = 3
        self.tileSize = CGSize(width: 1024, height: 1024)
    }
    
    override func draw(in ctx: CGContext) {
        super.draw(in: ctx)
        
        if (self.page != nil) {
            ctx.saveGState();
            
            var bounds = self.page!.bounds
            let transform = self.page!.transform()
            bounds = bounds.applying(transform);
            
            let viewWidth: CGFloat = NSWidth(self.bounds)
            let viewHeight: CGFloat = NSHeight(self.bounds)
            
            if (self.page!.rotation == -90 || self.page!.rotation == -270) {
                let height = bounds.size.height
                bounds.size.height = bounds.size.width
                bounds.size.width = height
            }
            
            ctx.scaleBy(x: viewWidth / bounds.size.width,
                        y: viewHeight / bounds.size.height);
            self.page!.drawEdit(with: .cropBox, to: ctx)
            ctx.restoreGState();
        }
    }
}

class KMPDFThumbnialPageView: NSView {
    internal var _page: CPDFPage?
    var page: CPDFPage? {
        get {
            self._page
        }
        set {
            self._page = newValue
            
            if pageLayer != nil {
                pageLayer.contents = nil
                pageLayer.delegate = nil
                pageLayer.removeFromSuperlayer()
            }
            
            pageLayer = KMPDFThumbnialPageLayer()
            pageLayer.frame = self.bounds
            pageLayer.page = newValue
            self.layer?.addSublayer(pageLayer)
        }
    }
    
    var pageLayer: KMPDFThumbnialPageLayer!
    
    override init(frame frameRect: NSRect) {
        super.init(frame: frameRect)
        
        self.wantsLayer = true
        self.layer?.backgroundColor = NSColor.white.cgColor
        
        self.shadow = NSShadow()
        self.layer?.shadowColor = NSColor.black.cgColor
        self.layer?.shadowOpacity = 0.2
        self.layer?.shadowRadius = 3
        self.layer?.shadowOffset = CGSize(width: 0, height: -3)
        
        if (pageLayer != nil) {
            pageLayer.frame = self.bounds;
        }
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
    }
    
    override func layout() {
        super.layout()
        
        if (pageLayer != nil) {
            pageLayer.frame = self.bounds;
            pageLayer.setNeedsDisplay()
        }
    }
    
}