//
//  CreateGroupView.swift
//  QuickLocation
//
//  Created by 八条 on 2026/6/2.
//

import UIKit
import RxSwift
import RxCocoa

class CreateGroupView: UIView {
    
    var disposeBag = DisposeBag()
    
    private let limitCount = 50
    private let tagMaxLength = 10
    
    var onConfirmAddTag: ((String) -> Void)?
    
    private func setupRx() {
        groupNameTF.rx.text.orEmpty
            .subscribe(onNext: { [weak self] text in
                guard let self = self else { return }
                if text.count > 10 {
                    self.groupNameTF.text = String(text.prefix(10))
                }
            })
            .disposed(by: disposeBag)
        
        Observable.merge(
            groupContentTV.rx.didChange.asObservable(),
            groupContentTV.rx.text.map { _ in () },
            groupContentTV.rx.methodInvoked(#selector(UITextView.paste(_:))).map { _ in () }
        )
            .throttle(.milliseconds(100), scheduler: MainScheduler.instance)
            .subscribe(onNext: { [weak self] in
                guard let self = self else { return }
                let count = self.groupContentTV.text.count
                self.placeholderLab.isHidden = count != 0
                
                if count > self.limitCount {
                    self.groupContentTV.text = String(self.groupContentTV.text.prefix(self.limitCount))
                    self.groupContentTV.selectedRange = NSRange(location: self.limitCount, length: 0)
                    return
                }
            })
            .disposed(by: disposeBag)
        
        addTagTF.rx.text.orEmpty
            .subscribe(onNext: { [weak self] text in
                guard let self = self else { return }
                if text.count > self.tagMaxLength {
                    self.addTagTF.text = String(text.prefix(self.tagMaxLength))
                }
                let count = self.addTagTF.text?.count ?? 0
                self.addTagCountLab.text = "\(count)/\(self.tagMaxLength)"
            })
            .disposed(by: disposeBag)
        
        sheetCancelBtn.rx.tap
            .subscribe(onNext: { [weak self] in
                self?.dismissAddTagSheet()
            })
            .disposed(by: disposeBag)
        
        sheetConfirmBtn.rx.tap
            .subscribe(onNext: { [weak self] in
                guard let self = self else { return }
                self.onConfirmAddTag?(self.addTagTF.text ?? "")
            })
            .disposed(by: disposeBag)
        
        addTagClearBtn.rx.tap
            .subscribe(onNext: { [weak self] in
                self?.addTagTF.text = ""
                self?.addTagCountLab.text = "0/\(self?.tagMaxLength ?? 10)"
            })
            .disposed(by: disposeBag)
    }
    
    private func setupUI() {
        addSubview(navBgView)
        addSubview(navView)
        addSubview(scrollView)
        addSubview(submitBtn)
        
        scrollView.addSubview(contentView)
        contentView.addSubview(iconCarousel)
        contentView.addSubview(typeNamePlaceholder)
        contentView.addSubview(groupNameTitleLab)
        contentView.addSubview(groupNameInputView)
        groupNameInputView.addSubview(groupNameTF)
        contentView.addSubview(groupContentTitleLab)
        contentView.addSubview(groupContentInputView)
        groupContentInputView.addSubview(groupContentTV)
        groupContentInputView.addSubview(placeholderLab)
        contentView.addSubview(tagTitleLab)
        contentView.addSubview(tagView)
        
        navBgView.layoutChain
            .edges(excludingEdge: .bottom)
            .heightToWidth(160/375)
        
        navView.layoutChain
            .edges(excludingEdge: .bottom)
            .height(kNaviHeight)
        
        submitBtn.layoutChain
            .bottom(kSafeBottomMargin + 24)
            .centerX()
            .edgesHorzontal(30)
            .height(56)
        
        scrollView.layoutChain
            .topToBottomOfView(navView)
            .edgesHorzontal()
            .bottomToTopOfView(submitBtn, offset: -12)
        
        contentView.layoutChain
            .edges()
            .widthToView(scrollView)
        
        iconCarousel.layoutChain
            .top(8)
            .edgesHorzontal()
            .height(130)
        
        typeNamePlaceholder.layoutChain
            .topToBottomOfView(iconCarousel, offset: 4)
            .centerX()
        
        groupNameTitleLab.layoutChain
            .topToBottomOfView(typeNamePlaceholder, offset: 24)
            .left(24)
        
        groupNameInputView.layoutChain
            .topToBottomOfView(groupNameTitleLab, offset: 10)
            .edgesHorzontal(20)
            .height(50)
        
        groupNameTF.layoutChain
            .edgesVertical()
            .left(16)
            .right(48)
        
        groupContentTitleLab.layoutChain
            .topToBottomOfView(groupNameInputView, offset: 18)
            .left(24)
        
        groupContentInputView.layoutChain
            .topToBottomOfView(groupContentTitleLab, offset: 10)
            .edgesHorzontal(20)
            .height(96)
        
        groupContentTV.layoutChain
            .top(8)
            .left(12)
            .right(48)
            .bottom(8)
        
        placeholderLab.layoutChain
            .topToView(groupContentTV, offset: 8)
            .leftToView(groupContentTV, offset: 5)
        
        tagTitleLab.layoutChain
            .topToBottomOfView(groupContentInputView, offset: 18)
            .left(24)
        
        tagView.layoutChain
            .topToBottomOfView(tagTitleLab, offset: 12)
            .edgesHorzontal(20)
            .height(28)
            .bottom(24)
        
        setupSheet()
    }
    
    func updateTagViewHeight() {
        tagView.collectionViewLayout.invalidateLayout()
        tagView.layoutIfNeeded()
        let height = max(28, tagView.collectionViewLayout.collectionViewContentSize.height)
        tagView.layoutChain.height(height)
    }
    
    func showAddTagSheet() {
        addTagTF.text = ""
        addTagCountLab.text = "0/\(tagMaxLength)"
        sheetOverlay.isHidden = false
        sheetOverlay.alpha = 0
        sheetPanel.transform = CGAffineTransform(translationX: 0, y: 40)
        UIView.animate(withDuration: 0.28, delay: 0, options: .curveEaseOut) {
            self.sheetOverlay.alpha = 1
            self.sheetPanel.transform = .identity
        } completion: { _ in
            self.addTagTF.becomeFirstResponder()
        }
    }
    
    func dismissAddTagSheet() {
        addTagTF.resignFirstResponder()
        UIView.animate(withDuration: 0.22, delay: 0, options: .curveEaseIn) {
            self.sheetOverlay.alpha = 0
            self.sheetPanel.transform = CGAffineTransform(translationX: 0, y: 40)
        } completion: { _ in
            self.sheetOverlay.isHidden = true
            self.addTagTF.text = ""
            self.addTagCountLab.text = "0/\(self.tagMaxLength)"
        }
    }
    
    // MARK: - Sheet
    
    private func setupSheet() {
        sheetOverlay.backgroundColor = UIColor.black.withAlphaComponent(0.45)
        sheetOverlay.isHidden = true
        addSubview(sheetOverlay)
        sheetOverlay.layoutChain.edges()
        
        sheetPanel.backgroundColor = .white
        sheetPanel.layer.cornerRadius = 24
        sheetPanel.layer.maskedCorners = [.layerMinXMinYCorner, .layerMaxXMinYCorner]
        sheetPanel.clipsToBounds = true
        sheetOverlay.addSubview(sheetPanel)
        sheetPanel.layoutChain.edgesHorzontal().bottom()
        
        sheetHeaderView.backgroundColor = UIColor(hexStr: "#E8F7FF")
        sheetPanel.addSubview(sheetHeaderView)
        sheetHeaderView.layoutChain.edgesHorzontal().top().height(56)
        
        sheetTitleLab.text = "添加标签"
        sheetTitleLab.font = .systemFont(ofSize: 16, weight: .medium)
        sheetTitleLab.textColor = ThemeManager.shared.color.titleAuxColor
        sheetTitleLab.textAlignment = .center
        sheetHeaderView.addSubview(sheetTitleLab)
        sheetTitleLab.layoutChain.center()
        
        sheetAddIcon.backgroundColor = UIColor(hexStr: "#D6F0FF")
        sheetAddIcon.cornerRadius = 8
        sheetAddIcon.contentMode = .center
        let plusConfig = UIImage.SymbolConfiguration(pointSize: 13, weight: .medium)
        sheetAddIcon.image = UIImage(systemName: "plus", withConfiguration: plusConfig)
        sheetAddIcon.tintColor = UIColor(hexStr: "#16B3FF")
        sheetPanel.addSubview(sheetAddIcon)
        sheetAddIcon.layoutChain
            .topToBottomOfView(sheetHeaderView, offset: 24)
            .left(20)
            .width(32)
            .height(32)
        
        addTagInputView.backgroundColor = UIColor(hexStr: "#F7F8FA")
        addTagInputView.cornerRadius = 10
        sheetPanel.addSubview(addTagInputView)
        
        addTagClearBtn.setImage(UIImage(systemName: "xmark.circle.fill"), for: .normal)
        addTagClearBtn.tintColor = UIColor(hexStr: "#FF5B5B")
        sheetPanel.addSubview(addTagClearBtn)
        addTagClearBtn.layoutChain
            .centerY(sheetAddIcon)
            .right(20)
            .width(22)
            .height(22)
        
        addTagInputView.layoutChain
            .centerY(sheetAddIcon)
            .leftToRightOfView(sheetAddIcon, offset: 10)
            .rightToLeftOfView(addTagClearBtn, offset: -10)
            .height(40)
        
        addTagInputView.addSubview(addTagTF)
        addTagInputView.addSubview(addTagCountLab)
        addTagCountLab.layoutChain
            .centerY()
            .right(12)
        addTagTF.layoutChain
            .edgesVertical()
            .left(12)
            .rightToLeftOfView(addTagCountLab, offset: -8)
        
        sheetPanel.addSubview(sheetCancelBtn)
        sheetPanel.addSubview(sheetConfirmBtn)
        
        sheetCancelBtn.layoutChain
            .topToBottomOfView(sheetAddIcon, offset: 28)
            .left(24)
            .height(44)
            .bottom(20 + kSafeBottomMargin)
        
        sheetConfirmBtn.layoutChain
            .leftToRightOfView(sheetCancelBtn, offset: 12)
            .right(24)
            .bottomToView(sheetCancelBtn)
            .heightToView(sheetCancelBtn)
            .widthToView(sheetCancelBtn)
        
        let tap = UITapGestureRecognizer(target: self, action: #selector(tapSheetMask))
        sheetOverlay.addGestureRecognizer(tap)
    }
    
    @objc private func tapSheetMask(_ gesture: UITapGestureRecognizer) {
        let point = gesture.location(in: sheetPanel)
        if sheetPanel.bounds.contains(point) { return }
        dismissAddTagSheet()
    }
    
    // MARK: - Views
    
    lazy var navBgView: UIImageView = {
        let iv = UIImageView()
        iv.image = UIImage(named: "Common/navBar_bg_2")
        iv.contentMode = .scaleAspectFill
        return iv
    }()
    
    lazy var navView: BaseNavigationView = {
        let nav = BaseNavigationView(title: "创建圈子")
        return nav
    }()
    
    lazy var scrollView: UIScrollView = {
        let view = UIScrollView()
        view.backgroundColor = .clear
        view.keyboardDismissMode = .onDrag
        view.showsVerticalScrollIndicator = false
        return view
    }()
    
    lazy var contentView: UIView = {
        let view = UIView()
        view.backgroundColor = .clear
        return view
    }()
    
    lazy var iconCarousel: CreateGroupIconCarouselView = {
        let view = CreateGroupIconCarouselView()
        return view
    }()
    
    lazy var typeNamePlaceholder: UIView = {
        let view = UIView()
        view.backgroundColor = .white
        view.cornerRadius = 10
        view.isUserInteractionEnabled = false
        
        view.addSubview(typeNameLab)
        typeNameLab.layoutChain
            .edgesVertical(10)
            .edgesHorzontal(31)
        
        return view
    }()
    
    lazy var typeNameLab: UILabel = {
        let label = UILabel()
        label.text = "未知"
        label.font = .systemFont(ofSize: 16, weight: .bold)
        label.textColor = UIColor(hexStr: "#3D3D3D")
        return label
    }()
    
    lazy var groupNameTitleLab: UILabel = {
        let label = UILabel()
        label.text = "圈子名称"
        label.font = .systemFont(ofSize: 14, weight: .medium)
        label.textColor = ThemeManager.shared.color.titleAuxColor
        return label
    }()
    
    lazy var groupNameInputView: UIView = {
        let view = UIView()
        view.backgroundColor = .white
        view.cornerRadius = 10
        
        let icon = UIImageView()
        icon.image = UIImage(named: "Group/edit")
        icon.contentMode = .scaleAspectFit
        view.addSubview(icon)
        icon.layoutChain
            .right(14)
            .centerY()
            .width(22)
            .height(22)
        
        return view
    }()
    
    lazy var groupNameTF: UITextField = {
        let textField = UITextField(frame: .zero)
        textField.font = UIFont.systemFont(ofSize: 14, weight: .medium)
        textField.textColor = ThemeManager.shared.color.titleAuxColor
        textField.placeholderColor(placeholder: "请输入圈子名称",
                                   color: UIColor(hexStr: "#999999", alpha: 1.0))
        return textField
    }()
    
    lazy var groupContentTitleLab: UILabel = {
        let label = UILabel()
        label.text = "圈子描述"
        label.font = .systemFont(ofSize: 14, weight: .medium)
        label.textColor = ThemeManager.shared.color.titleAuxColor
        return label
    }()
    
    lazy var groupContentInputView: UIView = {
        let view = UIView()
        view.backgroundColor = .white
        view.cornerRadius = 10
        
        let icon = UIImageView()
        icon.image = UIImage(named: "Group/edit")
        icon.contentMode = .scaleAspectFit
        view.addSubview(icon)
        icon.layoutChain
            .right(14)
            .bottom(14)
            .width(22)
            .height(22)
        
        return view
    }()
    
    lazy var groupContentTV: UITextView = {
        let textView = UITextView()
        textView.backgroundColor = .clear
        textView.font = .systemFont(ofSize: 14, weight: .medium)
        textView.textColor = ThemeManager.shared.color.titleAuxColor
        textView.isScrollEnabled = true
        textView.textContainerInset = UIEdgeInsets(top: 8, left: 0, bottom: 8, right: 0)
        return textView
    }()
    
    lazy var placeholderLab: UILabel = {
        let label = UILabel()
        label.text = "请输入.."
        label.textColor = ThemeManager.shared.color.contentColor
        label.font = .systemFont(ofSize: 14, weight: .medium)
        return label
    }()
    
    lazy var tagTitleLab: UILabel = {
        let label = UILabel()
        label.text = "选择标签"
        label.font = .systemFont(ofSize: 14, weight: .medium)
        label.textColor = ThemeManager.shared.color.titleAuxColor
        return label
    }()
    
    lazy var tagView: UICollectionView = {
        let layout = CreateGroupTagFlowLayout()
        layout.minimumInteritemSpacing = 8
        layout.minimumLineSpacing = 8
        layout.sectionInset = .zero
        
        let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
        cv.backgroundColor = .clear
        cv.isScrollEnabled = false
        cv.register(TagCell.self)
        return cv
    }()
    
    lazy var submitBtn: UIButton = {
        let btn = UIButton(type: .custom)
        btn.setTitle("创建", for: .normal)
        btn.setTitleColor(.white, for: .normal)
        btn.titleLabel?.font = FontManager.boboBold(18)
        btn.setBackgroundImage(UIImage(named: "Common/button_bg_2"), for: .normal)
        btn.cornerRadius = 20
        return btn
    }()
    
    private let sheetOverlay = UIView()
    private let sheetPanel = UIView()
    private let sheetHeaderView = UIView()
    private let sheetTitleLab = UILabel()
    private let sheetAddIcon = UIImageView()
    private let addTagInputView = UIView()
    
    lazy var addTagTF: UITextField = {
        let textField = UITextField(frame: .zero)
        textField.font = .systemFont(ofSize: 14, weight: .medium)
        textField.textColor = ThemeManager.shared.color.titleAuxColor
        textField.placeholderColor(placeholder: "请输入标签",
                                   color: UIColor(hexStr: "#999999", alpha: 1.0),
                                   font: .systemFont(ofSize: 14, weight: .medium))
        return textField
    }()
    
    lazy var addTagCountLab: UILabel = {
        let label = UILabel()
        label.text = "0/10"
        label.font = .systemFont(ofSize: 12, weight: .regular)
        label.textColor = ThemeManager.shared.color.contentColor
        return label
    }()
    
    lazy var addTagClearBtn: UIButton = {
        let btn = UIButton(type: .custom)
        return btn
    }()
    
    lazy var sheetCancelBtn: UIButton = {
        let btn = UIButton(type: .custom)
        btn.setTitle("取消", for: .normal)
        btn.setTitleColor(UIColor(hexStr: "#16B3FF"), for: .normal)
        btn.titleLabel?.font = .systemFont(ofSize: 15, weight: .medium)
        btn.backgroundColor = .white
        btn.borderWidth = 1
        btn.borderColor = UIColor(hexStr: "#16B3FF")
        btn.cornerRadius = 22
        return btn
    }()
    
    lazy var sheetConfirmBtn: UIButton = {
        let btn = UIButton(type: .custom)
        btn.setTitle("确定", for: .normal)
        btn.setTitleColor(.white, for: .normal)
        btn.titleLabel?.font = .systemFont(ofSize: 15, weight: .medium)
        btn.setBackgroundImage(UIImage(named: "Common/gradient_bg"), for: .normal)
        btn.cornerRadius = 22
        btn.clipsToBounds = true
        return btn
    }()
    
    override init(frame: CGRect) {
        super.init(frame: .zero)
        setupUI()
        setupRx()
        backgroundColor = UIColor(hexStr: "#FAFAFA")
    }

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

// MARK: - Icon Carousel

final class CreateGroupIconCarouselView: UIView {
    
    var onSelectIndex: ((Int) -> Void)?
    
    private let iconCount = 11
    private let itemSize: CGFloat = 80
    private var lastWidth: CGFloat = 0
    
    var selectedIndex: Int = 1 {
        didSet {
            guard oldValue != selectedIndex else { return }
            onSelectIndex?(selectedIndex)
        }
    }
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        clipsToBounds = false
        addSubview(collectionView)
        collectionView.layoutChain.edges()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        guard bounds.width > 0 else { return }
        if bounds.width != lastWidth {
            lastWidth = bounds.width
            let inset = max(0, (bounds.width - itemSize) / 2)
            flowLayout.sectionInset = UIEdgeInsets(top: 25, left: inset, bottom: 25, right: inset)
            collectionView.layoutIfNeeded()
            scrollToIndex(selectedIndex, animated: false)
        }
        applyTransforms()
    }
    
    private func scrollToIndex(_ index: Int, animated: Bool) {
        let item = max(0, min(iconCount - 1, index - 1))
        collectionView.scrollToItem(at: IndexPath(item: item, section: 0),
                                    at: .centeredHorizontally,
                                    animated: animated)
    }
    
    private func nearestIndex() -> Int {
        let centerX = collectionView.contentOffset.x + collectionView.bounds.width / 2
        var nearest = 0
        var minDist = CGFloat.greatestFiniteMagnitude
        for i in 0..<iconCount {
            guard let attr = collectionView.layoutAttributesForItem(at: IndexPath(item: i, section: 0)) else { continue }
            let dist = abs(attr.center.x - centerX)
            if dist < minDist {
                minDist = dist
                nearest = i
            }
        }
        return nearest
    }
    
    private func applyTransforms() {
        let midX = collectionView.contentOffset.x + collectionView.bounds.width / 2
        for cell in collectionView.visibleCells {
            guard let attr = collectionView.layoutAttributesForItem(at: collectionView.indexPath(for: cell) ?? IndexPath()) else { continue }
            let distance = abs(attr.center.x - midX)
            let scale = max(0.72, 1.25 - distance / 180)
            let alpha = max(0.45, 1 - distance / 220)
            cell.transform = CGAffineTransform(scaleX: scale, y: scale)
            cell.alpha = alpha
        }
    }
    
    private lazy var flowLayout: UICollectionViewFlowLayout = {
        let layout = UICollectionViewFlowLayout()
        layout.scrollDirection = .horizontal
        layout.itemSize = CGSize(width: itemSize, height: itemSize)
        layout.minimumLineSpacing = 18
        layout.minimumInteritemSpacing = 0
        return layout
    }()
    
    private lazy var collectionView: UICollectionView = {
        let cv = UICollectionView(frame: .zero, collectionViewLayout: flowLayout)
        cv.backgroundColor = .clear
        cv.showsHorizontalScrollIndicator = false
        cv.decelerationRate = .fast
        cv.clipsToBounds = false
        cv.register(CreateGroupIconCell.self)
        cv.dataSource = self
        cv.delegate = self
        return cv
    }()
}

extension CreateGroupIconCarouselView: UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        iconCount
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(for: indexPath) as CreateGroupIconCell
        cell.configure(UIImage(named: "GroupIcon/\(indexPath.item + 1)"))
        return cell
    }
    
    func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
        applyTransforms()
    }
    
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        selectedIndex = indexPath.item + 1
        collectionView.scrollToItem(at: indexPath, at: .centeredHorizontally, animated: true)
    }
    
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        applyTransforms()
    }
    
    func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
        let proposedCenter = targetContentOffset.pointee.x + scrollView.bounds.width / 2
        var nearest = 0
        var minDist = CGFloat.greatestFiniteMagnitude
        for i in 0..<iconCount {
            guard let attr = collectionView.layoutAttributesForItem(at: IndexPath(item: i, section: 0)) else { continue }
            let dist = abs(attr.center.x - proposedCenter)
            if dist < minDist {
                minDist = dist
                nearest = i
            }
        }
        if let attr = collectionView.layoutAttributesForItem(at: IndexPath(item: nearest, section: 0)) {
            targetContentOffset.pointee.x = attr.center.x - scrollView.bounds.width / 2
        }
        selectedIndex = nearest + 1
    }
    
    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
        selectedIndex = nearestIndex() + 1
        applyTransforms()
    }
    
    func scrollViewDidEndScrollingAnimation(_ scrollView: UIScrollView) {
        applyTransforms()
    }
}

final class CreateGroupIconCell: UICollectionViewCell {
    private let imageView: UIImageView = {
        let view = UIImageView()
        view.contentMode = .scaleAspectFill
        view.clipsToBounds = true
        view.cornerRadius = 18
        return view
    }()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        contentView.addSubview(imageView)
        imageView.layoutChain.edges()
        contentView.clipsToBounds = false
        clipsToBounds = false
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func configure(_ image: UIImage?) {
        imageView.image = image
    }
    
    override func prepareForReuse() {
        super.prepareForReuse()
        transform = .identity
        alpha = 1
    }
}

// MARK: - Tag Flow Layout

final class CreateGroupTagFlowLayout: UICollectionViewFlowLayout {
    private var alignedAttrs: [IndexPath: UICollectionViewLayoutAttributes] = [:]
    
    override func prepare() {
        super.prepare()
        alignedAttrs.removeAll()
        let rect = CGRect(origin: .zero, size: collectionViewContentSize)
        guard let original = super.layoutAttributesForElements(in: rect) else { return }
        let attrs = original.map { $0.copy() as! UICollectionViewLayoutAttributes }
        leftAlign(attrs)
        attrs.forEach { alignedAttrs[$0.indexPath] = $0 }
    }
    
    override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
        alignedAttrs.values.filter { $0.frame.intersects(rect) }
    }
    
    override func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
        alignedAttrs[indexPath] ?? super.layoutAttributesForItem(at: indexPath)
    }
    
    override func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
        collectionView?.bounds.width != newBounds.width
    }
    
    private func leftAlign(_ attrs: [UICollectionViewLayoutAttributes]) {
        var x = sectionInset.left
        var y = sectionInset.top
        var lineHeight: CGFloat = 0
        let maxX = (collectionView?.bounds.width ?? 0) - sectionInset.right
        for attr in attrs where attr.representedElementCategory == .cell {
            if x > sectionInset.left && x + attr.frame.width > maxX {
                x = sectionInset.left
                y += lineHeight + minimumLineSpacing
                lineHeight = 0
            }
            attr.frame.origin = CGPoint(x: x, y: y)
            x += attr.frame.width + minimumInteritemSpacing
            lineHeight = max(lineHeight, attr.frame.height)
        }
    }
}

// MARK: - TagCell

final class TagCell: UICollectionViewCell {
    static let reuseId = "TagCell"
    
    private let label: UILabel = {
        let l = UILabel()
        l.font = .systemFont(ofSize: 12, weight: .medium)
        l.textAlignment = .center
        return l
    }()
    
    private let plusView: UIImageView = {
        let view = UIImageView()
        let config = UIImage.SymbolConfiguration(pointSize: 13, weight: .medium)
        view.image = UIImage(systemName: "plus", withConfiguration: config)
        view.tintColor = .white
        view.contentMode = .center
        view.isHidden = true
        return view
    }()
    
    private var isTagSelected = false
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        contentView.addSubview(label)
        contentView.addSubview(plusView)
        label.layoutChain.edges()
        plusView.layoutChain.edges()
        contentView.layer.cornerRadius = 8
        contentView.backgroundColor = UIColor(hexStr: "#F0F2F5")
        updateStyle()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func prepareForReuse() {
        super.prepareForReuse()
        plusView.isHidden = true
        label.isHidden = false
        label.text = nil
    }
    
    static func preferredSize(for item: String) -> CGSize {
        if item == CreateGroupViewModel.addTagToken {
            return CGSize(width: 28, height: 28)
        }
        let font = UIFont.systemFont(ofSize: 12, weight: .medium)
        let textW = ceil((item as NSString).size(withAttributes: [.font: font]).width)
        return CGSize(width: max(52, textW + 20), height: 28)
    }
    
    func configure(_ text: String, isSelected: Bool) {
        plusView.isHidden = true
        label.isHidden = false
        label.text = text
        isTagSelected = isSelected
        contentView.layer.cornerRadius = 8
        updateStyle()
    }
    
    func configureAsAdd() {
        plusView.isHidden = false
        label.isHidden = true
        label.text = nil
        isTagSelected = false
        contentView.backgroundColor = UIColor(hexStr: "#16B3FF")
        contentView.layer.borderWidth = 0
        contentView.layer.cornerRadius = 8
    }
    
    func toggleSelection() {
        isTagSelected.toggle()
        updateStyle()
    }
    
    private func updateStyle() {
        if isTagSelected {
            label.textColor = UIColor(hexStr: "#16B3FF")
            contentView.backgroundColor = UIColor(hexStr: "#E3F6FF")
            contentView.layer.borderWidth = 1
            contentView.layer.borderColor = UIColor(hexStr: "#16B3FF").cgColor
        } else {
            label.textColor = ThemeManager.shared.color.titleAuxColor
            contentView.backgroundColor = UIColor(hexStr: "#F0F2F5")
            contentView.layer.borderWidth = 0
        }
    }
}