//
//  EmptyDataSet.swift
// JiuLaiBao
//
//  Created by 霹雳火 on 01/06/2018.
//  Copyright © 2018 GuoXiaoMei. All rights reserved.
//

import Foundation
import RxSwift
import UIKit

private var emptyDataSetAssociatedKey: UInt8 = 0

public extension DLWrapper where Base: UIScrollView {
    /// DLEmptyDataSet
    var emptyDataSet: DLEmptyDataSet? { objc_getAssociatedObject(base, &emptyDataSetAssociatedKey) as? DLEmptyDataSet  }
    
    ///
    /// - Parameters:
    ///   - customEmptyHandler: 自定义Empty样式回调，可以对empty进行设置
    ///   - customButtonDidTap: 自定义按钮点击回调
    ///   - didTapRefresh: 网络失败按钮点击事件回调
    /// - Returns: DLEmptyDataSet
    @discardableResult
    func addEmptyDataSet(customEmptyHandler: ((DLEmptyDataSet) -> Void)? = nil,
                         customButtonDidTap: (() -> Void)? = nil,
                         didTapRefresh: (() -> Void)? = nil) -> DLEmptyDataSet {
        let emptyDataSet = DLEmptyDataSet(scrollView: base)
        emptyDataSet.didTapRefresh = didTapRefresh
        emptyDataSet.customDidTap = customButtonDidTap
        customEmptyHandler?(emptyDataSet)
        objc_setAssociatedObject(base, &emptyDataSetAssociatedKey, emptyDataSet, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
        return emptyDataSet
    }
}

public struct EmptyDataSetConfig {
    static public var titleColor = UIColor(hexStr: "#666666")
    static public var detailColor = UIColor(hexStr: "#999999")
    static public var emptyNoDataTitle = "oapp_EmptyNoData"
    static public var emptyNoDataDetail = ""
    static public var emptyNoDataImage = UIImage(named: "empty_data")
    static public var emptyNetworkErrorTitle = "请检查网络连接"
    static public var emptyNetworkErrorDetail = ""
    static public var emptyNetworkErrorImage = UIImage(named: "empty_network")
    static public var emptyReloadButtonImage = UIImage(named: "empty_reload")
    static public var reloadButtonTitle = "重新加载"
    static public var customButtonTitle = ""
    static public var backgroundColor: UIColor = .clear
    static public var spaceHeight: CGFloat = 15.0
    
    /// 重置
    public static func resetConfig() {
        titleColor = UIColor(hexStr: "#666666")
        detailColor = UIColor(hexStr: "#999999")
        emptyNoDataTitle = "暂无数据"
        emptyNoDataDetail = ""
        emptyNoDataImage = UIImage(named: "empty_data")
        emptyNetworkErrorTitle = "请检查网络连接"
        emptyNetworkErrorDetail = ""
        emptyNetworkErrorImage = UIImage(named: "empty_network")
        emptyReloadButtonImage = UIImage(named: "empty_reload")
        customButtonTitle = ""
        backgroundColor = .clear
    }
}

public class DLEmptyDataSet: NSObject {
    
    private var disposeBag = DisposeBag()
    private weak var scrollView: UIScrollView!
    private var refreshStatus: RefreshStatus?
    private var isEmptyVariable = BehaviorSubject<Bool?>(value: nil)
    // 是否开始就显示empty占位图
    private var shouldBeForcedToDisplay = false
    public var titleColor = EmptyDataSetConfig.titleColor
    public var detailColor = EmptyDataSetConfig.detailColor
    public var emptyNoDataTitle = EmptyDataSetConfig.emptyNoDataTitle
    public var emptyNoDataDetail = EmptyDataSetConfig.emptyNoDataDetail
    public var emptyNoDataImage = EmptyDataSetConfig.emptyNoDataImage
    public var emptyNetworkErrorTitle = EmptyDataSetConfig.emptyNetworkErrorTitle
    public var emptyNetworkErrorDetail = EmptyDataSetConfig.emptyNetworkErrorDetail
    public var emptyNetworkErrorImage = EmptyDataSetConfig.emptyNetworkErrorImage
    public var emptyReloadButtonImage = EmptyDataSetConfig.emptyReloadButtonImage
    public var reloadButtonTitle = EmptyDataSetConfig.reloadButtonTitle
    public var customButtonTitle = EmptyDataSetConfig.customButtonTitle
    public var backgroundColor: UIColor = EmptyDataSetConfig.backgroundColor
    public var spaceHeight: CGFloat = EmptyDataSetConfig.spaceHeight
    public var offsetY: CGFloat = 0 {
        didSet {
            scrollView.reloadEmptyDataSet()
        }
    }
    
    public var didTapRefresh: (() -> Void)?
    public var customDidTap: (() -> Void)?
    
    required public init(scrollView: UIScrollView) {
        super.init()
        self.scrollView = scrollView
        scrollView.emptyDataSetSource = self
        scrollView.emptyDataSetDelegate = self
        isEmptyVariable.asObservable().subscribe(onNext: { [unowned self] value in
            if let _ = value {
                self.scrollView.reloadEmptyDataSet()
            }
        }).disposed(by: disposeBag)
    }
    
    public func update(status: RefreshStatus?, isEmpty: Bool, shouldForcedDisplay: Bool = false) {
        refreshStatus = status
        shouldBeForcedToDisplay = shouldForcedDisplay
        isEmptyVariable.onNext(isEmpty)
    }
    
    public func reset() {
        shouldBeForcedToDisplay = false
        refreshStatus = nil
        isEmptyVariable.onNext(false)
    }
}

extension DLEmptyDataSet: EmptyDataSetSource, EmptyDataSetDelegate {

    // MARK: DZNEmptyDataSetSource
    public func title(forEmptyDataSet _: UIScrollView) -> NSAttributedString? {
        let text = refreshStatus == .invalidData ? emptyNetworkErrorTitle : emptyNoDataTitle
        let attributes: [NSAttributedString.Key: Any] = [.font: UIFont.systemFont(ofSize: 13),
                                                         .foregroundColor: titleColor]
        return NSAttributedString(string: text, attributes: attributes)
    }
    
    public func description(forEmptyDataSet scrollView: UIScrollView) -> NSAttributedString? {
        let text = refreshStatus == .invalidData ? emptyNetworkErrorDetail : emptyNoDataDetail
        let attributes: [NSAttributedString.Key: Any] = [.font: UIFont.systemFont(ofSize: 13),
                                                         .foregroundColor: detailColor]
        return NSAttributedString(string: text, attributes: attributes)
    }
    
    public func buttonTitle(forEmptyDataSet scrollView: UIScrollView, for state: UIControl.State) -> String? {
        return refreshStatus == .invalidData ? "  \(reloadButtonTitle)  " : customButtonTitle.isEmpty ? nil : "  \(customButtonTitle)  "
    }
    
    public func buttonAttributedTitle(forEmptyDataSet scrollView: UIScrollView, for state: UIControl.State) -> NSAttributedString? {
//        let errorAttri = NSAttributedString(string: "oapp_Reload".localizedString,
//                                            font: UIFont.systemFont(ofSize: 15),
//                                            color: UIColor.dl.rgb666666)
//        return refreshStatus == .invalidData ? errorAttri : nil
        return nil
    }
    
    public func image(forEmptyDataSet _: UIScrollView) -> UIImage? {
        return refreshStatus == .invalidData ? emptyNetworkErrorImage : emptyNoDataImage
    }
    
//    public func buttonImage(forEmptyDataSet scrollView: UIScrollView!, for state: UIControl.State) -> UIImage! {
//        return refreshStatus == .invalidData ? emptyReloadButtonImage : nil
//    }
    
    public func backgroundColor(forEmptyDataSet _: UIScrollView) -> UIColor? {
        return backgroundColor
    }
    
    // MARK: DZNEmptyDataSetDelegate
    public func emptyDataSetShouldDisplay(_: UIScrollView) -> Bool {
        // 判断是否正在刷新
        guard refreshStatus != nil,
              let isDisplay = try? isEmptyVariable.value() else {
            return false
        }
        // 网络请求错误或者请求数据为空
        return isDisplay
    }
    
    public func emptyDataSetShouldAllowTouch(_ scrollView: UIScrollView) -> Bool {
        return true
    }
    
    public func emptyDataSetShouldAllowScroll(_ scrollView: UIScrollView) -> Bool {
        return true
    }
    
    public func emptyDataSet(_ scrollView: UIScrollView, didTapView view: UIView) {
        
    }
    
    public func emptyDataSet(_ scrollView: UIScrollView, didTapButton button: UIButton) {
        if customButtonTitle.isEmpty {
            reset()
            didTapRefresh?()
        }
        else {
            customDidTap?()
        }
    }
    
    public func emptyDataSetWillAppear(_ scrollView: UIScrollView) {
        scrollView.contentOffset = CGPoint()
    }
    
    public func verticalOffset(forEmptyDataSet scrollView: UIScrollView) -> CGFloat {
        return offsetY
    }
    
    public func spaceHeight(forEmptyDataSet scrollView: UIScrollView) -> CGFloat {
        return spaceHeight
    }
    
    @objc public func emptyDataSetShouldBeForcedToDisplay(_ scrollView: UIScrollView) -> Bool {
        return shouldBeForcedToDisplay
    }
}