//
//  LNUserRelationViewController.swift
//  Lanu
//
//  Created by OneeChan on 2025/12/19.
//

import Foundation
import UIKit
import SnapKit


extension UIView {
    func pushToRelationList(uid: String, tabType: LNUserRelationTabType = .follow) {
        let vc = LNUserRelationViewController()
        navigationController?.pushViewController(vc, animated: true)
        vc.locatedTo(tabType)
    }
}


enum LNUserRelationTabType: CaseIterable {
    case follow
    case fans
}


class LNUserRelationViewController: LNViewController {
    private var curTabType: LNUserRelationTabType = .follow {
        didSet {
            locatedTabTo(curTabType, animated: true)
        }
    }
    private let tabIndicator = UIImageView()
    private let followLabel = UILabel()
    private let fansLabel = UILabel()
    
    private let scrollView = UIScrollView()
    private let followList = LNUserRelationListView(curType: .follow)
    private let fansList = LNUserRelationListView(curType: .fans)
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        setupViews()
        
        let tabType = curTabType
        curTabType = tabType
    }
    
    func locatedTo(_ tab: LNUserRelationTabType) {
        view.layoutIfNeeded()
        curTabType = tab
    }
}

extension LNUserRelationViewController: LNUserRelationListViewDelegate {
    func onUserRelationListViewTotalChanged(view: LNUserRelationListView, total: Int) {
        switch view.curType {
        case .fans:
            fansLabel.text = .init(key: "A00234", total)
        case .follow:
            followLabel.text = .init(key: "A00238", total)
        }
    }
}

extension LNUserRelationViewController: UIScrollViewDelegate {
    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
        let page = Int(scrollView.contentOffset.x / scrollView.bounds.width)
        let tab = LNUserRelationTabType.allCases[page]
        locatedTabTo(tab, animated: true)
    }
}

extension LNUserRelationViewController {
    private func scrollTo(_ tab: LNUserRelationTabType, animated: Bool) {
        let page = LNUserRelationTabType.allCases.firstIndex(of: tab) ?? 0
        let offsetX = scrollView.bounds.width * CGFloat(page)
        scrollView.setContentOffset(.init(x: offsetX, y: 0), animated: animated)
    }
    
    private func locatedTabTo(_ tab: LNUserRelationTabType, animated: Bool) {
        let targetTab: UIView?
        switch tab {
        case .follow:
            targetTab = followLabel.superview
            followLabel.textColor = .text_5
            fansLabel.textColor = .text_2
        case .fans:
            targetTab = fansLabel.superview
            followLabel.textColor = .text_2
            fansLabel.textColor = .text_5
        }
        guard let targetTab else { return }
        
        tabIndicator.snp.remakeConstraints { make in
            make.center.equalTo(targetTab)
            make.height.equalTo(16)
        }
        scrollTo(tab, animated: animated)
        
        if animated {
            UIView.animate(withDuration: 0.25) { [weak self] in
                guard let self else { return }
                followLabel.superview?.superview?.layoutIfNeeded()
            }
        }
    }
    
    private func setupViews() {
        setupNavBar()
        
        scrollView.delegate = self
        scrollView.isPagingEnabled = true
        scrollView.showsVerticalScrollIndicator = false
        scrollView.showsHorizontalScrollIndicator = false
        view.addSubview(scrollView)
        scrollView.snp.makeConstraints { make in
            make.horizontalEdges.equalToSuperview()
            make.bottom.equalToSuperview()
            make.top.equalToSuperview()
        }
        
        followList.delegate = self
        scrollView.addSubview(followList)
        followList.snp.makeConstraints { make in
            make.verticalEdges.equalToSuperview()
            make.leading.equalToSuperview()
            make.width.height.equalToSuperview()
        }
        
        fansList.delegate = self
        scrollView.addSubview(fansList)
        fansList.snp.makeConstraints { make in
            make.verticalEdges.equalToSuperview()
            make.trailing.equalToSuperview()
            make.leading.equalTo(followList.snp.trailing)
            make.width.height.equalToSuperview()
        }
    }
    
    private func setupNavBar() {
        let stackView = UIStackView()
        stackView.axis = .horizontal
        stackView.spacing = 0
        stackView.distribution = .fillEqually
        setTitleView(stackView)
        stackView.snp.makeConstraints { make in
            make.width.equalTo(view.bounds.width).priority(.medium)
            make.height.equalTo(44)
        }
        
        tabIndicator.image = .icHomeTabSelected
        tabIndicator.contentMode = .scaleAspectFit
        stackView.addSubview(tabIndicator)
        
        let followButton = UIButton()
        followButton.addAction(UIAction(handler: { [weak self] _ in
            guard let self else { return }
            curTabType = .follow
        }), for: .touchUpInside)
        stackView.addArrangedSubview(followButton)
        
        followLabel.font = .heading_h3
        followLabel.textColor = .text_5
        followLabel.text = .init(key: "A00238", 0)
        followButton.addSubview(followLabel)
        followLabel.snp.makeConstraints { make in
            make.center.equalToSuperview()
        }
        
        let fansButton = UIButton()
        fansButton.addAction(UIAction(handler: { [weak self] _ in
            guard let self else { return }
            curTabType = .fans
        }), for: .touchUpInside)
        stackView.addArrangedSubview(fansButton)
        
        fansLabel.font = .heading_h3
        fansLabel.textColor = .text_5
        fansLabel.text = .init(key: "A00234", 0)
        fansButton.addSubview(fansLabel)
        fansLabel.snp.makeConstraints { make in
            make.center.equalToSuperview()
        }
    }
}