Visual_Novel_iOS/crush/Crush/Src/Components/UI/Placeholder/PlaceholderView.swift

//
//  PlaceholderView.swift
//  Crush
//
//  Created by Leon on 2025/7/14.
//

import SnapKit
import UIKit

/// A reusable placeholder view with an image and text label
class PlaceholderView: UIView {
    // MARK: - Properties

    lazy var emptyImage: UIImage? = {
        UIImage(named: "empty_placeholder_icon")
    }()

    var viewStartOffset: CGFloat = 0
    var startY: CGFloat = 0

    private let placeholderImageView: UIImageView = {
        let imageView = UIImageView()
        imageView.contentMode = .scaleAspectFit
        imageView.tintColor = .gray // Adjust tint for template images
        return imageView
    }()

    private let placeholderLabel: UILabel = {
        let label = UILabel()
        label.textAlignment = .center
        label.textColor = .gray
        label.font = .systemFont(ofSize: 16, weight: .regular)
        label.numberOfLines = 0 // Allow multiple lines
        return label
    }()

    // MARK: - Initialization

    init(text: String, viewStartOffset: CGFloat = 0) {
        super.init(frame: .zero)
        self.viewStartOffset = viewStartOffset
        setupViews(image: emptyImage)
        updateViewOffset(text: text)
    }

    init(text: String, startY: CGFloat = 0) {
        super.init(frame: .zero)
        self.startY = startY
        setupViews(image: emptyImage)
        updateViewStartY(text: text)
    }

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

    // MARK: - Setup

    private func setupViews(image: UIImage?) {
        isUserInteractionEnabled = false
        backgroundColor = .clear // Adjust as needed

        // Add subviews
        addSubview(placeholderImageView)
        addSubview(placeholderLabel)

        // Configure content
        placeholderImageView.image = image
    }

    // MARK: - Public Methods

    func updateViewOffset(text: String) {
        placeholderLabel.text = text
        placeholderImageView.snp.makeConstraints { make in
            make.centerX.equalToSuperview()
            make.centerY.equalToSuperview().offset((-40 + viewStartOffset) * 0.5) // Offset to position image above text
            make.size.equalTo(CGSize(width: 183, height: 135))
        }

        placeholderLabel.snp.makeConstraints { make in
            make.top.equalTo(placeholderImageView.snp.bottom).offset(16)
            make.left.right.equalToSuperview().inset(16)
        }
    }

    func updateViewStartY(text: String) {
        placeholderLabel.text = text
        placeholderImageView.snp.makeConstraints { make in
            make.centerX.equalToSuperview()
            make.top.equalToSuperview().offset(startY)
            make.width.height.equalTo(100) // Adjust size as needed
        }

        placeholderLabel.snp.makeConstraints { make in
            make.top.equalTo(placeholderImageView.snp.bottom).offset(16)
            make.left.right.equalToSuperview().inset(16)
        }
    }
}

// MARK: - UIView Extension

extension UIView {
    /// Adds a placeholder view with an image and text to the view
    /// - Parameters:
    ///   - text: The placeholder text
    /// - Returns: The created PlaceholderView instance
    @discardableResult
    func showEmpty(text: String, viewStartOffset: CGFloat = 0) -> PlaceholderView {
        // Remove any existing placeholder views
        subviews.filter { $0 is PlaceholderView }.forEach { $0.removeFromSuperview() }

        // Create and configure placeholder view
        let placeholderView = PlaceholderView(text: text, viewStartOffset: viewStartOffset)
        addSubview(placeholderView)

        // Setup Auto Layout
        placeholderView.snp.makeConstraints { make in
            make.edges.equalToSuperview()
        }
        
        placeholderView.setNeedsDisplay()
        placeholderView.layoutIfNeeded()

        return placeholderView
    }

    @discardableResult
    func showStartYEmpty(text: String, startY: CGFloat = 200) -> PlaceholderView {
        // Remove any existing placeholder views
        subviews.filter { $0 is PlaceholderView }.forEach { $0.removeFromSuperview() }

        // Create and configure placeholder view
        let placeholderView = PlaceholderView(text: text, startY: startY)
        addSubview(placeholderView)

        // Setup Auto Layout
        placeholderView.snp.makeConstraints { make in
            make.edges.equalToSuperview()
        }

        return placeholderView
    }

    /// Removes any existing placeholder view
    func removeEmpty() {
        subviews.filter { $0 is PlaceholderView }.forEach { $0.removeFromSuperview() }
    }
    
    func hideEmpty(){
        removeEmpty()
    }
    
    // MARK: - Public
    func setupEmpty(empty: Bool, startY: CGFloat? = 0,  msg: String?){
        if(empty){
            if let y = startY, y > 0{
                showStartYEmpty(text: msg ?? "", startY: y)
            }else{
                showEmpty(text: msg ?? "")
            }
        }else{
            removeEmpty()
        }
    }
}