import SwiftUI

struct MainHomeFollowingChatSection: View {
    let recentChats: [ChatRoomListItemResponse]
    let onTapTitle: () -> Void
    let onTapChatRoom: (Int, String) -> Void

    init(
        recentChats: [ChatRoomListItemResponse],
        onTapTitle: @escaping () -> Void = {},
        onTapChatRoom: @escaping (Int, String) -> Void = { _, _ in }
    ) {
        self.recentChats = recentChats
        self.onTapTitle = onTapTitle
        self.onTapChatRoom = onTapChatRoom
    }

    var body: some View {
        if !recentChats.isEmpty {
            VStack(alignment: .leading, spacing: SodaSpacing.s14) {
                SectionTitle(title: I18n.HomeFollowing.recentChatTitle, action: onTapTitle)

                ScrollView(.horizontal, showsIndicators: false) {
                    LazyHStack(alignment: .top, spacing: SodaSpacing.s8) {
                        ForEach(recentChats) { chat in
                            MainHomeFollowingChatItemView(chat: chat) {
                                onTapChatRoom(chat.roomId, chat.chatType)
                            }
                        }
                    }
                    .padding(.leading, SodaSpacing.s14)
                }
            }
        }
    }
}

private struct MainHomeFollowingChatItemView: View {
    let chat: ChatRoomListItemResponse
    let action: () -> Void

    var body: some View {
        Button(action: action) {
            HStack(alignment: .center, spacing: SodaSpacing.s12) {
                DownsampledKFImage(url: URL(string: chat.targetImageUrl), size: CGSize(width: 64, height: 64))
                    .clipShape(Circle())

                VStack(alignment: .leading, spacing: SodaSpacing.s4) {
                    HStack(alignment: .top, spacing: SodaSpacing.s6) {
                        if chat.isDirectMessage {
                            DirectTagView()
                        }

                        Spacer(minLength: 0)

                        Text(chat.relativeLastMessageAtText())
                            .appFont(size: 12, weight: .regular)
                            .foregroundColor(Color.gray500)
                            .lineLimit(1)
                    }
                    .frame(height: 19)

                    Text(chat.targetName)
                        .appFont(size: 14, weight: .bold)
                        .foregroundColor(.white)
                        .lineLimit(1)
                        .truncationMode(.tail)

                    Text(chat.lastMessage)
                        .appFont(size: 14, weight: .regular)
                        .foregroundColor(.white)
                        .lineLimit(1)
                        .truncationMode(.tail)
                }
                .frame(maxWidth: .infinity, alignment: .leading)
            }
            .padding(SodaSpacing.s14)
            .frame(width: 288, alignment: .leading)
            .background(Color.gray900)
            .cornerRadius(14)
        }
        .buttonStyle(.plain)
    }
}

private struct DirectTagView: View {
    var body: some View {
        Text(I18n.HomeFollowing.directTag)
            .appFont(size: 12, weight: .bold)
            .italic()
            .foregroundColor(.white)
            .padding(.horizontal, SodaSpacing.s4)
            .padding(.vertical, 2)
            .background(Color.soda400)
            .cornerRadius(4)
    }
}

private extension ChatRoomListItemResponse {
    var isDirectMessage: Bool {
        chatType == "DM"
    }

    func relativeLastMessageAtText(now: Date = Date()) -> String {
        DateParser.relativeTimeText(fromUTC: lastMessageAt, fallback: lastMessageAt, now: now)
    }
}

struct MainHomeFollowingChatSection_Previews: PreviewProvider {
    private static let previewImageUrl = "https://picsum.photos/500/500"

    static var previews: some View {
        MainHomeFollowingChatSection(
            recentChats: [
                ChatRoomListItemResponse(
                    roomId: 1,
                    chatType: "DM",
                    targetName: "크리에이터 이름",
                    targetImageUrl: previewImageUrl,
                    lastMessage: "마지막 대화 내용이 들어가는 부분 한줄만",
                    lastMessageAt: "2026-07-01T01:30:00Z"
                ),
                ChatRoomListItemResponse(
                    roomId: 2,
                    chatType: "GROUP",
                    targetName: "소다",
                    targetImageUrl: previewImageUrl,
                    lastMessage: "다음 대화 내용입니다",
                    lastMessageAt: "2026-07-01T01:20:00Z"
                )
            ]
        )
        .padding(.vertical, SodaSpacing.s20)
        .background(Color.black)
        .previewLayout(.sizeThatFits)
    }
}