import SwiftUI

struct CreatorChannelReplyDetailFeedView: View {
    let parentItem: CreatorChannelReplyDetailDisplayItem
    let replies: [CreatorChannelReplyDetailDisplayItem]
    let selectedActionItem: CreatorChannelReplyDetailDisplayItem?
    let canEdit: (CreatorChannelReplyDetailDisplayItem) -> Bool
    let canDelete: (CreatorChannelReplyDetailDisplayItem) -> Bool
    let onTapAction: (CreatorChannelReplyDetailDisplayItem) -> Void
    let onTapEdit: (CreatorChannelReplyDetailDisplayItem) -> Void
    let onTapDelete: (CreatorChannelReplyDetailDisplayItem) -> Void
    let onReplyAppear: (CreatorChannelReplyDetailDisplayItem) -> Void

    @State private var itemFrames = [CreatorChannelReplyDetailItemKey: CGRect]()

    var body: some View {
        ZStack(alignment: .topTrailing) {
            ScrollView(.vertical, showsIndicators: false) {
                VStack(alignment: .leading, spacing: 0) {
                    parentView

                    if replies.isEmpty == false {
                        repliesView
                            .padding(.top, SodaSpacing.s12)
                            .padding(.leading, 50)
                    }

                    Spacer(minLength: SodaSpacing.s20)
                }
                .padding(.horizontal, SodaSpacing.s14)
                .padding(.top, SodaSpacing.s16)
                .padding(.bottom, SodaSpacing.s20)
            }

            actionPopupLayer
                .zIndex(1)
        }
        .coordinateSpace(name: Self.coordinateSpaceName)
        .onPreferenceChange(CreatorChannelReplyDetailItemFramePreferenceKey.self) { frames in
            itemFrames.merge(frames) { _, new in new }
        }
    }

    @ViewBuilder
    private var actionPopupLayer: some View {
        if let selectedActionItem,
           let itemFrame = itemFrames[CreatorChannelReplyDetailItemKey(item: selectedActionItem)] {
            CreatorChannelReplyDetailActionPopup(
                canEdit: canEdit(selectedActionItem),
                canDelete: canDelete(selectedActionItem),
                onTapEdit: { onTapEdit(selectedActionItem) },
                onTapDelete: { onTapDelete(selectedActionItem) }
            )
            .padding(.top, itemFrame.minY + 32)
            .padding(.trailing, SodaSpacing.s14)
        }
    }

    private var parentView: some View {
        VStack(alignment: .leading, spacing: SodaSpacing.s12) {
            itemHeader(item: parentItem, profileSize: 42, showsSecret: true)

            Text(parentItem.content)
                .appFont(size: 16, weight: .regular)
                .foregroundColor(.white)
                .fixedSize(horizontal: false, vertical: true)
                .frame(maxWidth: .infinity, alignment: .leading)
                .padding(.leading, 50)
                .background(alignment: .topLeading) {
                    if replies.isEmpty == false {
                        GeometryReader { proxy in
                            CreatorChannelReplyDetailConnector()
                                .stroke(Color.gray800, style: StrokeStyle(lineWidth: 2, lineCap: .round, lineJoin: .round))
                                .frame(height: proxy.size.height + SodaSpacing.s12 + SodaSpacing.s20)
                        }
                    }
                }
        }
    }

    private var repliesView: some View {
        VStack(alignment: .leading, spacing: SodaSpacing.s8) {
            ForEach(replies) { reply in
                replyCard(reply)
                    .onAppear { onReplyAppear(reply) }
            }
        }
    }

    private func replyCard(_ item: CreatorChannelReplyDetailDisplayItem) -> some View {
        VStack(alignment: .leading, spacing: SodaSpacing.s8) {
            itemHeader(item: item, profileSize: 20, showsSecret: false)

            Text(item.content)
                .appFont(size: 16, weight: .regular)
                .foregroundColor(.white)
                .fixedSize(horizontal: false, vertical: true)
                .frame(maxWidth: .infinity, alignment: .leading)
        }
        .padding(SodaSpacing.s12)
        .frame(maxWidth: .infinity, alignment: .leading)
        .background(Color.gray900)
        .clipShape(RoundedRectangle(cornerRadius: SodaSpacing.s14, style: .continuous))
    }

    private func itemHeader(
        item: CreatorChannelReplyDetailDisplayItem,
        profileSize: CGFloat,
        showsSecret: Bool
    ) -> some View {
        HStack(alignment: .center, spacing: SodaSpacing.s8) {
            DownsampledKFImage(
                url: URL(string: item.profileImageUrl),
                size: CGSize(width: profileSize, height: profileSize)
            )
            .background(Color.white.opacity(0.6))
            .clipShape(Circle())

            Text(item.nickname)
                .appFont(size: profileSize > 20 ? 14 : 13, weight: .medium)
                .foregroundColor(.white)
                .lineLimit(1)

            Text(item.relativeTimeText)
                .appFont(size: 14, weight: .regular)
                .foregroundColor(Color.gray500)
                .lineLimit(1)

            if showsSecret && item.isSecret {
                Text(I18n.Explorer.secretComment)
                    .appFont(size: 11, weight: .medium)
                    .foregroundColor(Color.grayee)
                    .padding(.horizontal, 4)
                    .padding(.vertical, 2)
                    .background(Color.soda400.opacity(0.2))
                    .cornerRadius(3)
            }

            Spacer(minLength: 0)

            if canEdit(item) || canDelete(item) {
                Button(action: { onTapAction(item) }) {
                    Image("ic_new_more")
                        .resizable()
                        .frame(width: 24, height: 24)
                }
                .buttonStyle(.plain)
            }
        }
        .trackReplyDetailItemFrame(item)
    }

    fileprivate static let coordinateSpaceName = "CreatorChannelReplyDetailFeedView"
}

private struct CreatorChannelReplyDetailItemKey: Hashable {
    let id: Int
    let source: Int

    init(item: CreatorChannelReplyDetailDisplayItem) {
        id = item.id
        switch item.source {
        case .community:
            source = 0
        case .fanTalk:
            source = 1
        }
    }
}

private struct CreatorChannelReplyDetailItemFramePreferenceKey: PreferenceKey {
    static var defaultValue: [CreatorChannelReplyDetailItemKey: CGRect] = [:]

    static func reduce(
        value: inout [CreatorChannelReplyDetailItemKey: CGRect],
        nextValue: () -> [CreatorChannelReplyDetailItemKey: CGRect]
    ) {
        value.merge(nextValue()) { _, new in new }
    }
}

private extension View {
    func trackReplyDetailItemFrame(_ item: CreatorChannelReplyDetailDisplayItem) -> some View {
        background {
            GeometryReader { proxy in
                Color.clear.preference(
                    key: CreatorChannelReplyDetailItemFramePreferenceKey.self,
                    value: [CreatorChannelReplyDetailItemKey(item: item): proxy.frame(in: .named(CreatorChannelReplyDetailFeedView.coordinateSpaceName))]
                )
            }
        }
    }
}

private struct CreatorChannelReplyDetailConnector: Shape {
    func path(in rect: CGRect) -> Path {
        var path = Path()
        let avatarCenterX: CGFloat = 21
        let replyCardStartX: CGFloat = 50
        let connectorGap: CGFloat = 14
        let connectorEndX = replyCardStartX - connectorGap
        let startY: CGFloat = 0
        let endY = rect.height - 8
        let bendY = max(startY, endY - 14)

        path.move(to: CGPoint(x: avatarCenterX, y: startY))
        path.addLine(to: CGPoint(x: avatarCenterX, y: bendY))
        path.addQuadCurve(
            to: CGPoint(x: connectorEndX, y: endY),
            control: CGPoint(x: avatarCenterX, y: endY)
        )
        return path
    }
}