//
//  LNInterestSetupViewController.swift
//  Lanu
//
//  Created by OneeChan on 2025/12/3.
//

import Foundation
import UIKit
import SnapKit


extension UIView {
    func pushToInterestSetup(_ config: LNProfileUpdateConfig) {
        let vc = LNInterestSetupViewController(config: config)
        navigationController?.pushViewController(vc, animated: true)
    }
}


class LNInterestSetupViewController: LNViewController {
    private let updateConfig: LNProfileUpdateConfig
    
    private let horizentalSpace = 22.0
    private let lineSpace = 8.0
    private let itemSpacing = 13.0
    private let minWidth = 115.0
    private let itemHeight = 85.0
    static let headerHeight = 44.0
    private let collectionViewLayout = UICollectionViewFlowLayout()
    private let collectionView: UICollectionView
    
    private let nextButton = UIButton()
    private let bottomGradient = CAGradientLayer()
    
    private let maxCount = LNGameMateManager.gameSelectionMaxCount
    private var selectedIndexs: [IndexPath] = []
    private var games: [LNGameTypeItemVO] = LNGameMateManager.shared.curGameTypes
    
    init(config: LNProfileUpdateConfig) {
        updateConfig = config
        
        collectionView = UICollectionView(frame: .zero, collectionViewLayout: collectionViewLayout)
        
        super.init(nibName: nil, bundle: nil)
        
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        setupViews()
    }
    
    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        
        if let superlayer = bottomGradient.superlayer {
            bottomGradient.frame = superlayer.bounds
        }
    }
}

extension LNInterestSetupViewController: UICollectionViewDataSource, UICollectionViewDelegate {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        games[section].children.count
    }
    
    func numberOfSections(in collectionView: UICollectionView) -> Int {
        games.count
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: LNInterestItemCell.className, for: indexPath) as! LNInterestItemCell
        
        let item = games[indexPath.section].children[indexPath.row]
        cell.update(item)
        cell.inSelected = selectedIndexs.contains(indexPath)
        cell.isEnable = selectedIndexs.count < maxCount || selectedIndexs.contains(indexPath)
        
        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: LNInterestGroupHeader.className, for: indexPath) as! LNInterestGroupHeader
        
        let section = games[indexPath.section]
        view.update(section.name)
        
        return view
    }
    
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        let needReload: Bool
        if selectedIndexs.contains(indexPath) {
            needReload = selectedIndexs.count == maxCount
            selectedIndexs.removeAll { $0 == indexPath }
        } else if selectedIndexs.count < maxCount {
            selectedIndexs.append(indexPath)
            needReload = selectedIndexs.count == maxCount
        } else {
            needReload = false
        }
            
        if needReload {
            collectionView.reloadData()
        } else {
            collectionView.reloadItems(at: [indexPath])
        }
        checkNextButtonEnable()
    }
}

extension LNInterestSetupViewController {
    private func checkNextButtonEnable() {
        nextButton.isEnabled = selectedIndexs.count > 0
    }
    
    private func setupViews() {
        view.backgroundColor = .primary_1
        navigationBarColor = .clear
        
        let bg = UIImageView()
        bg.image = .icLoginInterestBg
        view.addSubview(bg)
        bg.snp.makeConstraints { make in
            make.horizontalEdges.equalToSuperview()
            make.top.equalTo(fakeNaviBgView)
        }
        
        let titleView = buildTitles()
        view.addSubview(titleView)
        titleView.snp.makeConstraints { make in
            make.horizontalEdges.equalToSuperview().inset(22)
            make.top.equalToSuperview().offset(22)
        }
        
        let listView = buildListView()
        view.addSubview(listView)
        listView.snp.makeConstraints { make in
            make.horizontalEdges.equalToSuperview().inset(horizentalSpace)
            make.top.equalTo(titleView.snp.bottom).offset(6)
        }
        
        let bottom = buildBottomView()
        view.addSubview(bottom)
        bottom.snp.makeConstraints { make in
            make.horizontalEdges.equalToSuperview()
            make.bottom.equalTo(view.safeAreaLayoutGuide.snp.bottom)
            make.top.equalTo(listView.snp.bottom).offset(-16)
        }
    }
    
    private func buildTitles() -> UIView {
        let stackView = UIStackView()
        stackView.axis = .vertical
        stackView.spacing = 6
        
        let mainLabel = UILabel()
        mainLabel.text = .init(key: "A00111")
        mainLabel.font = .heading_h1
        mainLabel.textColor = .text_5
        mainLabel.numberOfLines = 0
        stackView.addArrangedSubview(mainLabel)
        
        let descLabel = UILabel()
        descLabel.font = .body_m
        descLabel.textColor = .text_3
        descLabel.text = .init(key: "A00112")
        descLabel.numberOfLines = 0
        stackView.addArrangedSubview(descLabel)
        
        return stackView
    }
    
    private func buildListView() -> UIView {
        let count = floor(CGFloat((view.bounds.width - horizentalSpace * 2) + itemSpacing) / minWidth)
        let itemWidth = (view.bounds.width - horizentalSpace * 2 + itemSpacing) / count - itemSpacing
        collectionViewLayout.itemSize = .init(width: itemWidth, height: itemHeight)
        collectionViewLayout.minimumLineSpacing = lineSpace
        collectionViewLayout.minimumInteritemSpacing = itemSpacing
        collectionViewLayout.headerReferenceSize = .init(width: view.bounds.width - horizentalSpace * 2, height: Self.headerHeight)
//        collectionViewLayout.sectionHeadersPinToVisibleBounds = true
        
        collectionView.backgroundColor = .clear
        collectionView.dataSource = self
        collectionView.delegate = self
        collectionView.showsHorizontalScrollIndicator = false
        collectionView.showsVerticalScrollIndicator = false
        collectionView.register(LNInterestItemCell.self, forCellWithReuseIdentifier: LNInterestItemCell.className)
        collectionView.register(LNInterestGroupHeader.self, forSupplementaryViewOfKind: UICollectionView.elementKindSectionHeader, withReuseIdentifier: LNInterestGroupHeader.className)
        collectionView.contentInset = .init(top: 0, left: 0, bottom: 20, right: 0)
        
        return collectionView
    }
    
    private func buildBottomView() -> UIView {
        let container = UIView()
        
        bottomGradient.colors = [
            UIColor.white.withAlphaComponent(0).cgColor,
            UIColor.primary_1.cgColor,
            UIColor.primary_1.cgColor
        ]
        bottomGradient.locations = [0, 0.3, 1]
        bottomGradient.startPoint = .init(x: 0, y: 0)
        bottomGradient.endPoint = .init(x: 0, y: 1)
        container.layer.addSublayer(bottomGradient)
        
        nextButton.setBackgroundImage(.primary_8, for: .normal)
        nextButton.setTitle(.init(key: "A00113"), for: .normal)
        nextButton.setTitleColor(.text_1, for: .normal)
        nextButton.titleLabel?.font = .heading_h3
        nextButton.layer.cornerRadius = 23.5
        nextButton.clipsToBounds = true
        nextButton.isEnabled = false
        nextButton.addAction(UIAction(handler: { [weak self] _ in
            guard let self else { return }
            let interests = selectedIndexs.compactMap {
                self.games[$0.section].children[$0.row].code
            }
            updateConfig.interest = interests
            LNProfileManager.shared.modifyMyProfile(config: updateConfig) { [weak self] success in
                guard let self else { return }
                guard success else { return }
                navigationController?.popToRootViewController(animated: true)
                LNGameMateManager.shared.getGameTypeList { _ in }
            }
        }), for: .touchUpInside)
        container.addSubview(nextButton)
        nextButton.snp.makeConstraints { make in
            make.horizontalEdges.equalToSuperview().inset(16)
            make.top.equalToSuperview().offset(16)
            make.bottom.equalToSuperview().offset(-4)
            make.height.equalTo(47)
        }
        
        return container
    }
}

private class LNInterestItemCell: UICollectionViewCell {
    private let ic = UIImageView()
    private let nameLabel = UILabel()
    private let bg = UIImageView()
    
    var inSelected: Bool = false {
        didSet {
            bg.image = inSelected ? .icLoginInterestItemSelected : .icLoginInterestItem
        }
    }
    var isEnable: Bool = true {
        didSet {
            contentView.alpha = isEnable ? 1.0 : 0.5
            isUserInteractionEnabled = isEnable
        }
    }
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        contentView.addSubview(bg)
        bg.snp.makeConstraints { make in
            make.center.equalToSuperview()
            make.width.equalTo(102)
            make.height.equalTo(85)
        }
        
        ic.layer.cornerRadius = 25
        ic.clipsToBounds = true
        ic.backgroundColor = .white
        bg.addSubview(ic)
        ic.snp.makeConstraints { make in
            make.centerX.equalToSuperview()
            make.top.equalToSuperview().offset(7)
            make.width.height.equalTo(50)
        }
        
        nameLabel.font = .body_s
        nameLabel.textColor = .text_5
        nameLabel.textAlignment = .center
        bg.addSubview(nameLabel)
        nameLabel.snp.makeConstraints { make in
            make.horizontalEdges.equalToSuperview().inset(6)
            make.bottom.equalToSuperview().offset(-6)
        }
    }
    
    func update(_ item: LNGameCategoryItemVO) {
        ic.sd_setImage(with: URL(string: item.icon))
        nameLabel.text = item.name
        
        let curState = isSelected
        isSelected = curState
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

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