//
//  GroupChatVC.swift
//  QuickLocation
//
//  Created by 八条 on 2026/6/4.
//

import UIKit
import RxSwift
import RxCocoa
import RxDataSources
import OpenIMSDK

final class GroupChatVC: BaseViewController {

    override var isNavigationBarHidden: Bool { true }

    fileprivate var rootView: GroupChatView!
    private let viewModel = GroupChatViewModel()
    private var msgListener: MessageListenerProxy?

    // MARK: - Init
    init(groupId: String) {
        viewModel.groupId = groupId
        super.init(nibName: nil, bundle: nil)
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func loadView() {
        rootView = GroupChatView(frame: UIScreen.main.bounds)
        view = rootView
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        bindViewModel()
        requestGroupInfoByKey()
        reactiveAction()
        setupMessageListener()
    }

    // MARK: - Bindings
    private func bindViewModel() {
        viewModel.output.messages
            .skip(1)
            .map { [ChatSectionModel(model: "", items: $0)] }
            .observe(on: MainScheduler.asyncInstance)
            .bind(to: rootView.tableView.rx.items(dataSource: dataSource))
            .disposed(by: disposeBag)

        viewModel.output.messages
            .skip(1)
            .observe(on: MainScheduler.asyncInstance)
            .subscribe(onNext: { [weak self] _ in
                self?.scrollToBottom()
            })
            .disposed(by: disposeBag)

        let emojiItems = UITableViewCell.emojiFileNames.map { $0 }
        Observable.just([SectionModel(model: "", items: emojiItems)])
            .bind(to: rootView.emojiCollectionView.rx.items(dataSource: emojiDataSource))
            .disposed(by: disposeBag)
    }

    private var hasScrolledToBottom = false

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        if !hasScrolledToBottom {
            hasScrolledToBottom = true
            scrollToBottom()
        }
    }

    private func scrollToBottom() {
        let count = dataSource.sectionModels.first?.items.count ?? 0
        guard count > 0 else { return }
        DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
            self.rootView.tableView.layoutIfNeeded()
            let indexPath = IndexPath(row: count - 1, section: 0)
            self.rootView.tableView.scrollToRow(at: indexPath, at: .bottom, animated: false)
        }
    }

    // MARK: - dataSource
    private lazy var dataSource: RxTableViewSectionedReloadDataSource<ChatSectionModel> = {
        RxTableViewSectionedReloadDataSource<ChatSectionModel> { _, tableView, indexPath, item in
            switch item {
            case let .send(msg):
                let cell: TextSendMsgCell = tableView.dequeueReusableCell(for: indexPath)
                cell.configure(msg)
                return cell
            case let .received(msg):
                let cell: TextReceivedMsgCell = tableView.dequeueReusableCell(for: indexPath)
                cell.configure(msg)
                return cell
            case let .emojiSend(msg):
                let cell: EmojiSendMsgCell = tableView.dequeueReusableCell(for: indexPath)
                cell.configure(msg)
                return cell
            case let .emojiReceived(msg):
                let cell: EmojiReceivedMsgCell = tableView.dequeueReusableCell(for: indexPath)
                cell.configure(msg)
                return cell
            case let .voiceSend(msg):
                let cell: VoiceSendMsgCell = tableView.dequeueReusableCell(for: indexPath)
                cell.configure(msg)
                return cell
            case let .voiceReceived(msg):
                let cell: VoiceReceivedMsgCell = tableView.dequeueReusableCell(for: indexPath)
                cell.configure(msg)
                return cell
            case let .notification(text):
                let cell: NotificationMsgCell = tableView.dequeueReusableCell(for: indexPath)
                cell.configure(text)
                return cell
            }
        }
    }()

    private lazy var emojiDataSource: RxCollectionViewSectionedReloadDataSource<SectionModel<String, String>> = {
        RxCollectionViewSectionedReloadDataSource<SectionModel<String, String>> { _, collectionView, indexPath, name in
            let cell: EmojiPanelCell = collectionView.dequeueReusableCell(for: indexPath)
            if let path = Bundle.main.path(forResource: name, ofType: "json") {
                cell.configure(path: path)
            }
            return cell
        }
    }()

    // MARK: - Message Listener
    private func setupMessageListener() {
        msgListener = MessageListenerProxy { [weak self] msg in
            guard let self = self, msg.groupID == self.viewModel.groupId else { return }
            self.viewModel.onReceiveMessage(msg)
        }
        OIMManager.callbacker.addAdvancedMsgListener(listener: msgListener!)
    }

    // MARK: - Actions
    private func reactiveAction() {
        rootView.backBtn.rx.tap
            .subscribe(onNext: { _ in
                AppRouter.shared.popOrDismiss()
            })
            .disposed(by: disposeBag)

        rootView.emojiBtn.rx.tap
            .subscribe(onNext: { [weak self] _ in
                guard let self = self else { return }
                let show = self.rootView.emojiPanelView.isHidden
                self.rootView.emojiPanelView.isHidden = !show
                let offset: CGFloat = show ? -220 : 0
                UIView.animate(withDuration: 0.25) {
                    self.rootView.bottomBar.transform = CGAffineTransform(translationX: 0, y: offset)
                    self.rootView.tableView.transform = CGAffineTransform(translationX: 0, y: offset)
                }
                if show {
                    self.rootView.textField.resignFirstResponder()
                    EmojiPanelCell.preloadAnimations()
                }
            })
            .disposed(by: disposeBag)

        rootView.emojiCollectionView.rx.modelSelected(String.self)
            .subscribe(onNext: { [weak self] name in
                guard let self = self, let idx = UITableViewCell.emojiFileNames.firstIndex(of: name) else { return }
                self.viewModel.input.sendMessage.onNext("js_emoji:\(idx)")
            })
            .disposed(by: disposeBag)

        let sendText = Observable.merge(
            rootView.sendBtn.rx.tap.map { [weak self] _ in self?.rootView.textField.text ?? "" },
            rootView.textField.rx.controlEvent(.editingDidEndOnExit)
                .map { [weak self] _ in self?.rootView.textField.text ?? "" }
        )
        .filter { !$0.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty }
        .do(onNext: { [weak self] _ in self?.rootView.textField.text = "" })

        sendText
            .bind(to: viewModel.input.sendMessage)
            .disposed(by: disposeBag)
    }

    // MARK: - API
    private func requestGroupInfoByKey() {
        GroupService.groupInfoByKey(viewModel.groupId).subscribe { response in
            guard let model = response.model else { return }
            self.viewModel.memberList = response.list
            self.rootView.groupNameLabel.text = model.name
            self.rootView.groupAvatarView.image = model.groupIcon
            self.viewModel.loadMessages()
        }.disposed(by: disposeBag)
    }
}

// MARK: - MessageListenerProxy
private class MessageListenerProxy: NSObject, OIMAdvancedMsgListener {
    private let handler: (OIMMessageInfo) -> Void

    init(handler: @escaping (OIMMessageInfo) -> Void) {
        self.handler = handler
    }

    func onRecvNewMessage(_ msg: OIMMessageInfo) {
        handler(msg)
    }
}