import UIKit

final class RDEPUBImageViewerCoordinator {

    private weak var presentingController: UIViewController?
    private let theme: RDEPUBReaderTheme

    init(presentingController: UIViewController, theme: RDEPUBReaderTheme) {
        self.presentingController = presentingController
        self.theme = theme
    }

    // MARK: - From Native Text Path (UIImage already resolved)

    func presentImage(_ image: UIImage, sourceRect: CGRect? = nil, altText: String? = nil) {
        let config = RDEPUBImageViewController.Configuration(
            image: image,
            sourceRect: sourceRect,
            altText: altText,
            theme: theme
        )
        let viewerVC = RDEPUBImageViewController(configuration: config)
        presentingController?.present(viewerVC, animated: true)
    }

    // MARK: - From WebView Path (need to resolve from src URL)

    func presentImageFromWebView(
        src: String,
        baseHref: String?,
        resourceResolver: RDEPUBResourceResolver
    ) {
        guard let image = loadImage(src: src, baseHref: baseHref, resourceResolver: resourceResolver) else {
            return
        }
        presentImage(image)
    }

    // MARK: - Private

    private func loadImage(
        src: String,
        baseHref: String?,
        resourceResolver: RDEPUBResourceResolver
    ) -> UIImage? {
        let pathPart = src.components(separatedBy: "#").first ?? src
        guard !pathPart.isEmpty else { return nil }

        let fileURL: URL?
        if let baseHref {
            fileURL = resourceResolver.fileURL(forReference: pathPart, relativeToHref: baseHref)
        } else {
            let normalized = resourceResolver.normalizedHref(pathPart)
            fileURL = normalized.flatMap { resourceResolver.fileURL(forRelativePath: $0) }
        }

        // 经统一资源入口读取：加密图片由 provider 解密，明文图片直读磁盘
        guard let fileURL, let data = resourceResolver.resourceData(at: fileURL) else { return nil }
        return UIImage(data: data)
    }
}