//
//  ExcelViewSwifty.swift
//  YunYingSwift
//
//  Created by AlasKu on 17/2/10.
//  Copyright © 2017年 innostic. All rights reserved.
//

import UIKit
import NVActivityIndicatorView

let AKCollectionViewCellIdentifier = "AKCollectionView_Cell"
let AKCollectionViewHeaderIdentifier = "AKCollectionView_Header"

@objc protocol AKExcelViewDelegate : NSObjectProtocol {
    
    @objc optional func excelView(_ excelView: AKExcelView, didSelectItemAt indexPath: IndexPath)
    @objc optional func excelView(_ excelView: AKExcelView, viewAt indexPath: IndexPath) -> UIView?
    @objc optional func excelView(_ excelView: AKExcelView, attributedStringAt indexPath: IndexPath) -> NSAttributedString?
}

class AKExcelView: UIView , UICollectionViewDelegate , UICollectionViewDataSource , UIScrollViewDelegate , UICollectionViewDelegateFlowLayout{
    
    /// Delegate
    weak var delegate : AKExcelViewDelegate?
    /// CellTextMargin
    var textMargin : CGFloat = 5
    /// Cell Max width
    var itemMaxWidth : CGFloat = 200
    /// cell Min width
    var itemMinWidth : CGFloat = 50
    /// cell heihth
    var itemHeight : CGFloat = 44
    /// header Height
    var headerHeight : CGFloat = 44
    /// header BackgroundColor
    var headerBackgroundColor : UIColor = UIColor.lightGray
    /// header Text Color
    var headerTextColor : UIColor = UIColor.black
    /// header Text Font
    var headerTextFontSize : UIFont = UIFont.systemFont(ofSize: 15)
    /// contenTCell TextColor
    var contentTextColor : UIColor = UIColor.black
    /// content backgroung Color
    var contentBackgroundColor : UIColor = UIColor.white
    /// content Text Font
    var contentTextFontSize : UIFont = UIFont.systemFont(ofSize: 13)
    /// letf freeze column
    var leftFreezeColumn : Int = 1
    /// header Titles
    var headerTitles : [String]?
    /// content Data
    var contentData : Array<NSObject>?
    /// 颜色支持
    var contentDataColor: [[UIColor]]?
    /// set Column widths
    var columnWidthSetting : Dictionary<Int, CGFloat>?
    /// CelledgeInset
    var itemInsets : UIEdgeInsets?
    /// showsProperties
    var properties : Array<String>?
    /// autoScrollItem default is false
    var autoScrollToNearItem = false
    /// if set, there is no loading view when reload datas. default is true
    var isNeedLoadingView = true
    
    fileprivate lazy var horizontalShadow : CAShapeLayer = {  //水平阴影
        let s = CAShapeLayer()
        s.strokeColor = UIColor.lightGray.cgColor
        s.shadowColor = UIColor.black.cgColor
        s.shadowOffset = CGSize.init(width: 2, height: 0)
        s.shadowOpacity = 1
        return s
    }()
    
    fileprivate lazy var veritcalShadow : CAShapeLayer = {   //垂直阴影
        let s = CAShapeLayer()
        s.strokeColor = UIColor.lightGray.cgColor
        s.shadowColor = UIColor.black.cgColor
        s.shadowOffset = CGSize.init(width: 0, height: 3)
        s.shadowOpacity = 1
        return s
    }()

    // MARK: - Public Method
    override init(frame: CGRect) {
        super.init(frame: frame)
        setup()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setup()
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        setUpFrames()
    }
    
    func reloadData() {
        
        if isNeedLoadingView {
            
            // 开启Loading
            NVActivityIndicatorPresenter.sharedInstance.startAnimating(ActivityData(message: "数据加载中...", color: UIColor.loding()), NVActivityIndicatorView.DEFAULT_FADE_IN_ANIMATION)
        }

        
        DispatchQueue.global().sync {
            
            self.dataManager.caculateData()
            DispatchQueue.main.async {
                
                if self.isNeedLoadingView {
                    
                    NVActivityIndicatorPresenter.sharedInstance.stopAnimating(NVActivityIndicatorView.DEFAULT_FADE_OUT_ANIMATION)
                }
                
                self.setUpFrames()
                self.headFreezeCollectionView.reloadData()
                self.headMovebleCollectionView.reloadData()
                self.contentFreezeCollectionView.reloadData()
                self.contentMoveableCollectionView.reloadData()
            }
        }
    }
    
    func sizeForItem(item: Int) -> CGSize {
        
        if item < leftFreezeColumn {
            return NSCoder.cgSize(for: self.dataManager.freezeItemSize[item])
        } else {
            return NSCoder.cgSize(for: self.dataManager.slideItemSize[item - leftFreezeColumn])
        }
    }
    
    //MARK: - Private Method
    private func setup() {
        
        dataManager.excelView = self
        clipsToBounds = true
        
        
        addSubview(headFreezeCollectionView)
        addSubview(contentFreezeCollectionView)
        addSubview(contentScrollView)
        
        contentScrollView.addSubview(headMovebleCollectionView)
        contentScrollView.addSubview(contentMoveableCollectionView)
        
        contentMoveableCollectionView.contentInset = UIEdgeInsets(top: -1, left: 0, bottom: 0, right: 0)
        contentFreezeCollectionView.contentInset = UIEdgeInsets(top: -1, left: 0, bottom: 0, right: 0)

        layer.addSublayer(horizontalShadow)
        contentScrollView.layer.addSublayer(veritcalShadow)
    }
    
   fileprivate func showHorizontalDivideShadowLayer() {
    if horizontalShadow.path == nil {
        let path = UIBezierPath()
        path.move(to: CGPoint(x: 0, y: headerHeight))
        path.addLine(to: CGPoint(x: min(self.bounds.width, self.dataManager.freezeWidth + self.dataManager.slideWidth), y: headerHeight))
        path.lineWidth = 0.5
        horizontalShadow.path = path.cgPath
    }
    }
    
    fileprivate func dismissHorizontalDivideShadowLayer() {
        horizontalShadow.path = nil
    }
    
    fileprivate func showVerticalDivideShadowLayer() {
        if veritcalShadow.path == nil {
            let path = UIBezierPath()
            let heigh = contentScrollView.contentSize.height // + headFreezeCollectionView.contentSize.height
            path.move(to: CGPoint(x: 0, y: 0))
            path.addLine(to: CGPoint(x: 0, y: heigh))
            path.lineWidth = 0.5
            veritcalShadow.path = path.cgPath
        }
    }
    
    fileprivate func dismissVerticalDivideShadowLayer() {
        veritcalShadow.path = nil
    }
    
    fileprivate func setUpFrames() {
        
        let width = bounds.width
        let height = bounds.height
        
        if headerTitles != nil {
            
            headFreezeCollectionView.frame = CGRect(x: 0, y: 0, width: dataManager.freezeWidth, height: headerHeight)
            contentFreezeCollectionView.frame = CGRect(x: 0, y: headerHeight, width: dataManager.freezeWidth, height: height - headerHeight)
            
            contentScrollView.frame = CGRect(x: dataManager.freezeWidth, y: 0, width: width - dataManager.freezeWidth , height: height)
            contentScrollView.contentSize = CGSize(width: dataManager.slideWidth, height: height)
            
            headMovebleCollectionView.frame = CGRect(x: 0, y: 0, width: dataManager.slideWidth, height: headerHeight)
            contentMoveableCollectionView.frame = CGRect(x: 0, y: headerHeight, width: dataManager.slideWidth, height: height - headerHeight)
        } else {
            
            contentFreezeCollectionView.frame = CGRect(x: 0, y: 0, width: dataManager.freezeWidth, height: height)
            
            contentScrollView.frame = CGRect(x: dataManager.freezeWidth, y: 0, width: width - dataManager.freezeWidth, height: height)
            contentScrollView.contentSize = CGSize(width: dataManager.slideWidth, height: height)
            
            contentMoveableCollectionView.frame = CGRect(x: 0, y: 0, width: dataManager.slideWidth, height: height)
        }
    }
    
    //MARK: - 懒加载
    fileprivate let dataManager : AKExcelDataManager = AKExcelDataManager()
    
    fileprivate lazy var headFreezeCollectionView : UICollectionView = {
        
        return UICollectionView.init(delelate: self, datasource: self)
    }()

    fileprivate lazy var headMovebleCollectionView : UICollectionView = {
        
        return UICollectionView.init(delelate: self, datasource: self)
    }()

    fileprivate lazy var contentFreezeCollectionView : UICollectionView = {
        
        return UICollectionView.init(delelate: self, datasource: self)
    }()

    fileprivate lazy var contentMoveableCollectionView : UICollectionView = {
        
        return UICollectionView.init(delelate: self, datasource: self)
    }()

    fileprivate lazy var contentScrollView : UIScrollView = {
        
        let slideScrollView = UIScrollView()
        slideScrollView.bounces = false
        slideScrollView.showsHorizontalScrollIndicator = true
        slideScrollView.delegate = self
        
        return slideScrollView
    }()

}

//MARK: - UICollectionView Delegate & DataSource & collectionPrivate
extension AKExcelView {
    
     func numberOfSections(in collectionView: UICollectionView) -> Int {
        
        if collectionView == headMovebleCollectionView || collectionView == headFreezeCollectionView {
            return 1
        }
        return contentData?.count ?? 0
    }
    
     func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        
        guard let firstBodyData = self.contentData?.first else { return 0 }
        
        if collectionView == headFreezeCollectionView || collectionView == contentFreezeCollectionView {
            return leftFreezeColumn
        } else {

            if let pros = properties {
                return pros.count - leftFreezeColumn
            }
            let slideColumn = firstBodyData.propertyNames().count - leftFreezeColumn
            return slideColumn
        }
    }
    
     func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: AKCollectionViewCellIdentifier, for: indexPath) as! AKExcelCollectionViewCell
        cell.horizontalMargin = self.textMargin
        self.configCells(collectionView: collectionView, cell: cell, indexPath: indexPath)
        
        return cell
    }
    
    private func configCells(collectionView:UICollectionView ,cell:AKExcelCollectionViewCell ,indexPath: IndexPath) {
        
        var targetIndexPath = indexPath

        if collectionView == headFreezeCollectionView {
            
            cell.textLabel.text = headerTitles?[indexPath.row]
            cell.backgroundColor = headerBackgroundColor
            cell.textLabel.font = headerTextFontSize
        } else if collectionView == headMovebleCollectionView {
            
            cell.backgroundColor = headerBackgroundColor
            cell.textLabel.text = headerTitles?[indexPath.item + leftFreezeColumn]
            cell.textLabel.font = headerTextFontSize
            targetIndexPath = NSIndexPath(item: indexPath.item + leftFreezeColumn, section: indexPath.section) as IndexPath
        }else if (collectionView == contentFreezeCollectionView) {
            let text = dataManager.contentFreezeData[indexPath.section][indexPath.item]
            cell.textLabel.text = text
            cell.backgroundColor = contentBackgroundColor
            cell.textLabel.textColor = contentTextColor
            cell.textLabel.font = contentTextFontSize
            targetIndexPath = NSIndexPath(item: indexPath.item, section: indexPath.section + 1) as IndexPath
        } else {
            let text = dataManager.contentSlideData[indexPath.section][indexPath.item]
            cell.textLabel.text = text
            cell.backgroundColor = contentBackgroundColor
            if let contentDataColor = contentDataColor {
                cell.textLabel.textColor = contentDataColor[indexPath.section][indexPath.item + 1]
            } else {
                cell.textLabel.textColor = contentTextColor
            }
            cell.textLabel.font = contentTextFontSize
            targetIndexPath = NSIndexPath(item: indexPath.item + leftFreezeColumn, section: indexPath.section + 1) as IndexPath
        }
        
        self.customViewInCell(cell: cell, indexPath: targetIndexPath)
        self.attributeStringInCell(cell: cell, indexPath: targetIndexPath)
    }
    
     func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        if (contentData?.count == 0) || self.dataManager.freezeItemSize.count == 0 || self.dataManager.slideItemSize.count == 0 {
            
            return CGSize.zero
        } else {
            
            if (collectionView == headFreezeCollectionView ||
                collectionView == contentFreezeCollectionView) {
                
                return NSCoder.cgSize(for: self.dataManager.freezeItemSize[indexPath.item])
            } else {
                
                return NSCoder.cgSize(for: self.dataManager.slideItemSize[indexPath.item])
            }
        }
    }
    
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        
        var targetIndexPath = indexPath
        if collectionView == headFreezeCollectionView {
            
        } else if (collectionView == headMovebleCollectionView) {
            targetIndexPath = NSIndexPath.init(item: indexPath.item + leftFreezeColumn, section: indexPath.section) as IndexPath
        } else if (collectionView == contentFreezeCollectionView) {
            targetIndexPath = NSIndexPath.init(item: indexPath.item, section: indexPath.section + 1) as IndexPath
        } else {
            targetIndexPath = NSIndexPath.init(item: indexPath.item + leftFreezeColumn, section: indexPath.section + 1) as IndexPath
        }
        self.delegate?.excelView?(self, didSelectItemAt: targetIndexPath)
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
        
        if itemInsets != nil {
            return itemInsets!
        }
        return UIEdgeInsets.zero
    }
}

//MARK: - UISCrollViewDelegate
extension AKExcelView {
    
     func scrollViewDidScroll(_ scrollView: UIScrollView) {
        
        if scrollView != contentScrollView {
            contentFreezeCollectionView.contentOffset = scrollView.contentOffset
            contentMoveableCollectionView.contentOffset = scrollView.contentOffset
            
            if scrollView.contentOffset.y > 1 {
                showHorizontalDivideShadowLayer()
            } else {
                dismissHorizontalDivideShadowLayer()
            }

        }else{
            dPrint("scrollView.contentOffset.y is \(scrollView.contentOffset.y)")
            if (scrollView.contentOffset.x > 0) {
                showVerticalDivideShadowLayer()
            } else {
                dismissVerticalDivideShadowLayer()
            }
            CATransaction.begin()
            CATransaction.setDisableActions(true)
            veritcalShadow.transform = CATransform3DMakeTranslation(scrollView.contentOffset.x, 0, 0)
            CATransaction.commit()
        }
    }
    
    func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {

        if autoScrollToNearItem && scrollView == contentScrollView && !decelerate {
            scrollEndAnimation(scrollView: scrollView)

        }
    }
    
    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
        if scrollView == contentScrollView && autoScrollToNearItem {
            scrollEndAnimation(scrollView: scrollView)
        }
    }
    
    fileprivate func scrollEndAnimation(scrollView: UIScrollView) {
    
        let offSetX = scrollView.contentOffset.x
        
        let deltaOffSets = dataManager.slideItemOffSetX.compactMap({ (offset) -> CGFloat in
            
            return abs(offset - offSetX)
        })
        
        var min:CGFloat = deltaOffSets[0]
        
        for i in 0 ..< deltaOffSets.count {
            if deltaOffSets[i] < min {
                min = deltaOffSets[i]
            }
        }
        let index = deltaOffSets.firstIndex(of: min)
        let slideToOffset = dataManager.slideItemOffSetX[index!]
        
        let scrollViewWidth = bounds.width - dataManager.freezeWidth
        
        dPrint("dataManager.slideWidth - offSetX - scrollViewWidth is \(dataManager.slideWidth - offSetX - scrollViewWidth)")
        if abs(dataManager.slideWidth - offSetX - scrollViewWidth) <= 1 { // FIXME: 不知为何，有一些误差
            
            return
        }
        
        UIView.animate(withDuration: 0.5, animations: {
            scrollView.contentOffset.x = slideToOffset
        })
    }
}

//MARK: - CollectionView Extension
extension UICollectionView {
    
    /**
     *  遍历构造函数
     */
    
    convenience init(delelate: UICollectionViewDelegate , datasource: UICollectionViewDataSource){
        
        let flowLayout = UICollectionViewFlowLayout()
        flowLayout.minimumLineSpacing = 0
        flowLayout.minimumInteritemSpacing = 0
        flowLayout.headerReferenceSize = CGSize(width: kScreenWidth, height: 0)
        
        self.init(frame: CGRect.zero, collectionViewLayout: flowLayout)
        
        dataSource = datasource
        delegate = delelate
        register(AKExcelCollectionViewCell.self, forCellWithReuseIdentifier: AKCollectionViewCellIdentifier)
        backgroundColor = UIColor.clear
        showsVerticalScrollIndicator = false
        translatesAutoresizingMaskIntoConstraints = false
        if #available(iOS 11.0, *) {
            self.contentInsetAdjustmentBehavior = .never
        }
    }
}

//MARK: - AKExcelView Delegate Implemention
extension AKExcelView {
    
     fileprivate func customViewInCell(cell : AKExcelCollectionViewCell , indexPath : IndexPath) {
        
        let customView = delegate?.excelView?(self, viewAt: indexPath)
            cell.customView = customView
    }
    
     fileprivate func attributeStringInCell(cell: AKExcelCollectionViewCell , indexPath : IndexPath) {
        
        let attributeString = delegate?.excelView?(self, attributedStringAt: indexPath)
        if attributeString != nil {
            cell.textLabel.attributedText = attributeString
        }
    }
}