import Foundation

struct ThumbnailListGenerator {

    private let factory: TemplateFactory

    let files: FileProcessor

    init(factory: TemplateFactory, files: FileProcessor) {
        self.factory = factory
        self.files = files
    }

    func generateContent(items: [ThumbnailInfo], style: ThumbnailStyle) throws -> String {
        try items.map { try itemContent($0, style: style) }
            .joined(separator: "\n")
    }

    private func itemContent(_ thumbnail: ThumbnailInfo, style: ThumbnailStyle) throws -> String {
        var content = [ThumbnailKey : String]()
        content[.url] = thumbnail.url.unwrapped { "href=\"\($0)\"" }
        content[.image] = thumbnail.imageHtmlUrl
        content[.title] = thumbnail.title
        content[.image2x] = thumbnail.imageHtmlUrl.insert("@2x", beforeLast: ".")
        content[.corner] = thumbnail.cornerText.unwrapped {
            factory.largeThumbnail.makeCorner(text: $0)
        }

        try files.requireImage(
            source: thumbnail.imageFilePath,
            destination: thumbnail.imageFilePath,
            width: style.width,
            desiredHeight: style.height,
            createDoubleVersion: true)

        return try factory.thumbnail(style: style).generate(content, shouldIndent: false)
    }
}