//
//  KMPageIndicator.swift
//  PDF Reader Pro
//
//  Created by tangchao on 2023/10/10.
//

import Cocoa

@objc(TCPageIndicatorDelegate)
protocol KMPageIndicatorDelegate: AnyObject {
    func pageIndicator(_ pageIndicator: KMPageIndicator, didSelectPageAt index: UInt)
}

@objc (TCPageIndicator)
@objcMembers class KMPageIndicator: NSView {
    weak var delegate: KMPageIndicatorDelegate?
    var selectedColor: NSColor?
    var normalColor: NSColor?
    
    var indicatorMargin: CGFloat = 8.0 {
        didSet {
            self.needsDisplay = true
        }
    }
    var currentPage: UInt = 0 {
        didSet {
            self.needsDisplay = true
        }
    }
    
    var numberOfPages: UInt = 0 {
        didSet {
            self.needsDisplay = true
        }
    }
    var pageIndicatorSize: NSSize = NSMakeSize(6, 6) {
        didSet {
            self.needsDisplay = true
        }
    }
    
    // 是否响应事件 [默认为 YES ]
    var enabled = true
    
    private var _indicatorRects: [NSValue]?
    
    override init(frame frameRect: NSRect) {
        super.init(frame: frameRect)
        
        self.initDefaultValue()
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        
        self.initDefaultValue()
    }
    
    func initDefaultValue() {
        self.selectedColor = NSColor.gray
        self.normalColor = NSColor.gray.withAlphaComponent(0.5)
        
        self._indicatorRects = [NSValue](repeating: NSValue(rect: NSZeroRect), count: 10)
    }
    
    override func draw(_ dirtyRect: NSRect) {
        super.draw(dirtyRect)
        
        var indicatorAreaWidth = 0.0
        if (self.numberOfPages > 0) {
            indicatorAreaWidth = self.pageIndicatorSize.width * self.numberOfPages.cgFloat + self.indicatorMargin * (self.numberOfPages-1).cgFloat
        }
        
        var leftPosition = (self.bounds.size.width - indicatorAreaWidth) * 0.5
        let topPadding = (self.bounds.size.height - self.pageIndicatorSize.height) * 0.5
        
        self._indicatorRects?.removeAll()
        for i in 0 ..< self.numberOfPages {
            let position = NSMakePoint(leftPosition, topPadding)
            let rect = NSMakeRect(position.x, position.y, self.pageIndicatorSize.width, self.pageIndicatorSize.height)
            self._indicatorRects?.append(NSValue(rect: rect))
            
            let path = NSBezierPath(ovalIn: rect)
            if (self.currentPage == i) {
                self.selectedColor?.setFill()
            } else {
                self.normalColor?.setFill()
            }
            path.fill()
            leftPosition += (self.pageIndicatorSize.width + self.indicatorMargin)
        }
    }
    
    override func mouseDown(with event: NSEvent) {
        super.mouseDown(with: event)
        
        if (self.enabled == false) {
            return
        }
        
        let eventLocation = event.locationInWindow
        /// 转换成视图的本地坐标
        let pointInView = self.convert(eventLocation, from: nil)
        for i in 0 ..< self.numberOfPages {
            if let datas = self._indicatorRects {
                let rect = KMRectInset(datas[Int(i)].rectValue, -2, -2)
                if (NSPointInRect(pointInView, rect)) {
                    self.currentPage = i
                    
                    self.delegate?.pageIndicator(self, didSelectPageAt: i)
                }
            }
        }
    }
}