import Foundation

struct OverviewPageGenerator {

    private let factory: LocalizedSiteTemplate

    init(factory: LocalizedSiteTemplate) {
        self.factory = factory
    }

    func generate(
        section: Element,
        language: String) {
            let path = section.localizedPath(for: language)
            let url = files.urlInOutputFolder(path)

            let metadata = section.localized(for: language)
            let backLinkText = section.backLinkText(for: language)

            var content = [PageTemplate.Key : String]()
            content[.head] = factory.pageHead.generate(page: section, language: language)
            let languageButton = section.nextLanguage(for: language)
            content[.topBar] = factory.topBar.generate(
                sectionUrl: section.sectionUrl(for: language),
                languageButton: languageButton)
            content[.contentClass] = "overview"
            content[.header] = makeHeader(metadata: metadata, language: language, backText: backLinkText)
            content[.content] = makeContent(section: section, language: language)
            content[.footer] = section.customFooterContent()
            guard factory.page.generate(content, to: url) else {
                return
            }
            log.add(info: "Generated \(path)", source: section.path)
    }

    private func makeContent(section: Element, language: String) -> String {
        if section.hasNestingElements {
            return factory.overviewSection.generate(
                sections: section.elements,
                in: section,
                language: language,
                sectionItemCount: section.overviewItemCount)
        } else {
            return factory.overviewSection.generate(section: section, language: language)
        }
    }

    private func makeHeader(metadata: Element.LocalizedMetadata,
                            language: String,
                            backText: String?) -> String {
        var content = [HeaderKey : String]()
        content[.title] = metadata.title
        #warning("Add title suffix")
        content[.subtitle] = metadata.subtitle
        content[.titleText] = metadata.description
        content[.backLink] = backText.unwrapped { factory.makeBackLink(text: $0, language: language) }
        return factory.factory.centeredHeader.generate(content)
    }
}