//
//  HomeMenuIconFactory.swift
//  suixinkan
//

import UIKit

/// 首页 / 全部功能菜单图标加载，统一 SF Symbol 与资源图的视觉尺寸。
enum HomeMenuIconFactory {

    /// 菜单图标统一使用的逻辑画布尺寸。
    static let canvasSize = CGSize(width: 24, height: 24)

    /// 与菜单图标槽位（约 24–26pt）对齐的系统图标配置。
    static let symbolConfiguration = UIImage.SymbolConfiguration(pointSize: 18, weight: .medium)

    private static let imageCache = NSCache<NSString, UIImage>()

    /// 优先加载 Assets 资源图；否则加载 SF Symbol，并统一渲染到固定画布。
    static func image(named iconName: String) -> UIImage? {
        let cacheKey = iconName as NSString
        if let cachedImage = imageCache.object(forKey: cacheKey) {
            return cachedImage
        }

        guard let sourceImage = UIImage(named: iconName)
            ?? UIImage(systemName: iconName, withConfiguration: symbolConfiguration) else {
            return nil
        }

        let normalizedImage = renderOnFixedCanvas(sourceImage)
        imageCache.setObject(normalizedImage, forKey: cacheKey)
        return normalizedImage
    }

    private static func renderOnFixedCanvas(_ image: UIImage) -> UIImage {
        let sourceSize = image.size
        guard sourceSize.width > 0, sourceSize.height > 0 else {
            return image
        }

        let scale = min(canvasSize.width / sourceSize.width, canvasSize.height / sourceSize.height)
        let drawSize = CGSize(width: sourceSize.width * scale, height: sourceSize.height * scale)
        let drawRect = CGRect(
            x: (canvasSize.width - drawSize.width) / 2,
            y: (canvasSize.height - drawSize.height) / 2,
            width: drawSize.width,
            height: drawSize.height
        )
        let renderer = UIGraphicsImageRenderer(size: canvasSize)
        let renderedImage = renderer.image { _ in
            image.withRenderingMode(.alwaysOriginal).draw(in: drawRect)
        }
        return renderedImage.withRenderingMode(.alwaysTemplate)
    }
}