//
//  LNJoinUsSelectSkillView.swift
//  Gami
//
//  Created by OneeChan on 2026/1/19.
//

import Foundation
import UIKit
import SnapKit


protocol LNJoinUsSelectSkillViewDelegate: AnyObject {
    func joinUsSelectSkillView(view: LNJoinUsSelectSkillView, didSelect skill: LNGameCategoryItemVO)
}


class LNJoinUsSelectSkillView: UIView {
    private let columns = 4
    private let collectionViewLayout = UICollectionViewFlowLayout()
    private let collectionView: UICollectionView
    
    private var categories: [LNGameTypeItemVO] = []
    
    weak var delegate: LNJoinUsSelectSkillViewDelegate?
    
    override init(frame: CGRect) {
        collectionView = UICollectionView(frame: .zero, collectionViewLayout: collectionViewLayout)
        super.init(frame: frame)
        
        setupViews()
        
        update(categories: LNGameMateManager.shared.curGameTypes)
    }
    
    private func update(categories: [LNGameTypeItemVO]) {
        self.categories = categories
        collectionView.reloadData()
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        
        let width = (collectionView.bounds.width - collectionViewLayout.minimumInteritemSpacing) / CGFloat(columns) - collectionViewLayout.minimumInteritemSpacing
        collectionViewLayout.itemSize = .init(width: width, height: 68)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

extension LNJoinUsSelectSkillView: UICollectionViewDataSource, UICollectionViewDelegate {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        categories[section].children.count
    }
    
    func numberOfSections(in collectionView: UICollectionView) -> Int {
        categories.count
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: LNJoinUsSelectSkillCell.className, for: indexPath) as! LNJoinUsSelectSkillCell
        
        let item = categories[indexPath.section].children[indexPath.row]
        cell.tabItemView.update(item)
        
        return cell
    }
    
    func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
        guard kind == UICollectionView.elementKindSectionHeader else {
            return UICollectionReusableView()
        }
        
        let view = collectionView.dequeueReusableSupplementaryView(ofKind: UICollectionView.elementKindSectionHeader, withReuseIdentifier: LNJoinUsSelectSkillHeader.className, for: indexPath) as! LNJoinUsSelectSkillHeader
        
        let section = categories[indexPath.section]
        view.update(section.name)
        
        return view
    }
    
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        let category = categories[indexPath.section]
        let game = category.children[indexPath.row]
        delegate?.joinUsSelectSkillView(view: self, didSelect: game)
    }
}

extension LNJoinUsSelectSkillView {
    private func setupViews() {
        collectionViewLayout.itemSize = .init(width: 77, height: 68)
        collectionViewLayout.minimumLineSpacing = 10
        collectionViewLayout.minimumInteritemSpacing = 12
        collectionViewLayout.headerReferenceSize = .init(width: 100, height: LNJoinUsSelectSkillHeader.height)
        collectionViewLayout.sectionInset = .init(top: 0, left: 12, bottom: 40, right: 12)
        
        collectionView.backgroundColor = .clear
        collectionView.dataSource = self
        collectionView.delegate = self
        collectionView.contentInsetAdjustmentBehavior = .never
        collectionView.showsHorizontalScrollIndicator = false
        collectionView.showsVerticalScrollIndicator = false
        collectionView.register(LNJoinUsSelectSkillCell.self, forCellWithReuseIdentifier: LNJoinUsSelectSkillCell.className)
        collectionView.register(LNJoinUsSelectSkillHeader.self, forSupplementaryViewOfKind: UICollectionView.elementKindSectionHeader, withReuseIdentifier: LNJoinUsSelectSkillHeader.className)
        addSubview(collectionView)
        collectionView.snp.makeConstraints { make in
            make.horizontalEdges.equalToSuperview().inset(6)
            make.top.equalToSuperview().offset(17)
            make.bottom.equalToSuperview()
        }
    }
}

private class LNJoinUsSelectSkillCell: UICollectionViewCell {
    let tabItemView = LNHomeGameTabItemView()
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        contentView.addSubview(tabItemView)
        tabItemView.snp.makeConstraints { make in
            make.edges.equalToSuperview()
        }
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

private class LNJoinUsSelectSkillHeader: UICollectionReusableView {
    static let height = 36
    private let titleLabel = UILabel()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        snp.makeConstraints { make in
            make.height.equalTo(Self.height)
        }
        
        titleLabel.font = .heading_h2
        titleLabel.textColor = .text_5
        addSubview(titleLabel)
        titleLabel.snp.makeConstraints { make in
            make.bottom.equalToSuperview().offset(-8)
            make.leading.equalToSuperview().offset(10)
        }
    }
    
    func update(_ title: String) {
        titleLabel.text = title
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}