//
//  EnhancePagerModule.swift
//  FollowNative
//
//  Created by Innei on 2025/3/30.
//

import ExpoModulesCore

public class EnhancePagerViewModule: Module {
    public func definition() -> ModuleDefinition {
        Name("EnhancePagerView")

        View(EnhancePagerView.self) {
            OnViewDidUpdateProps { view in
                view.initizlize()
            }

            Prop("page") { (view: EnhancePagerView, index: Int) in
                view.page = index
            }

            Prop("pageGap") { (view: EnhancePagerView, gap: Int) in
                view.pageGap = gap
            }

            Prop("transitionStyle") { (view: EnhancePagerView, style: TransitionStyle?) in
                guard let style = style else { return }
                view.transitionStyle = style
            }

            AsyncFunction("setPage") { (view: EnhancePagerView, index: Int) in
                view.pageController?.setCurrentPage(index: index)
            }

            AsyncFunction("getCurrentPage") { view in
                view.pageController?.getCurrentPageIndex()
            }

            AsyncFunction("getState") { view -> String? in
                if let pageController = view.pageController {
                    return pageController.getState().rawValue
                }
                return nil
            }

            Events("onPageChange")
            Events("onScroll")
            Events("onScrollBegin")
            Events("onScrollEnd")
            Events("onPageWillAppear")
        }
    }
}

enum TransitionStyle: String, Enumerable {
    case scroll
    case pageCurl
    func toUIPageViewControllerTransitionStyle() -> UIPageViewController.TransitionStyle {
        switch self {
        case .scroll:
            return .scroll
        case .pageCurl:
            return .pageCurl
        }
    }
}

private class EnhancePagerView: ExpoView {
    fileprivate var pageController: EnhancePagerController?

    private let onScroll = EventDispatcher()
    private let onScrollBegin = EventDispatcher()
    private let onScrollEnd = EventDispatcher()
    private let onPageChange = EventDispatcher()
    private let onPageWillAppear = EventDispatcher()

    private var pageViews: [UIView] = []

    required init(appContext: AppContext? = nil) {
        super.init(appContext: appContext)
    }

    override func insertSubview(_ view: UIView, at index: Int) {
        pageViews.insert(view, at: index)
        pageController?.insertPageView(view: view)
    }

    func willRemoveSubview(_ subview: UIView, at index: Int) {
        pageViews.remove(at: index)
        pageController?.removePageView(at: index)
    }

    // Props
    var page: Int = 0 {
        willSet {
            pageController?.setCurrentPage(index: newValue)
        }
    }

    var pageGap = 20
    var transitionStyle: TransitionStyle = .scroll

    func initizlize() {
        pageController = EnhancePagerController(pageViews: pageViews, initialPageIndex: page,
                                                transitionStyle: transitionStyle.toUIPageViewControllerTransitionStyle(),
                                                options: [
                                                    .interPageSpacing: pageGap,
                                                ])
        guard let pageController = pageController else { return }
        addSubview(pageController.view)
        pageController.view.snp.makeConstraints { make in
            make.edges.equalToSuperview()
        }

        pageController.onPageIndexChange = { [weak self] index in
            self?.onPageChange(["index": index])
        }
        pageController.onScrollStart = { [weak self] index in
            self?.onScrollBegin(["index": index])
        }
        pageController.onScroll = { [weak self] percent, direction in
            self?.onScroll(["percent": percent, "direction": direction.rawValue])
        }
        pageController.onScrollEnd = { [weak self] index in
            self?.onScrollEnd(["index": index])
        }
        pageController.onPageWillAppear = { [weak self] index in
            self?.onPageWillAppear(["index": index])
        }
    }

    #if RCT_NEW_ARCH_ENABLED
        override func mountChildComponentView(_ childComponentView: UIView, index: Int) {
            if childComponentView is EnhancePageView {
                insertSubview(childComponentView, at: index)
            }
        }

        override func unmountChildComponentView(_ childComponentView: UIView, index: Int) {
            if childComponentView is EnhancePageView {
                willRemoveSubview(childComponentView, at: index)
            }
        }
    #endif
}