import Foundation

struct OverviewPageGenerator {

    private let factory: LocalizedSiteTemplate

    private let results: GenerationResultsHandler

    init(factory: LocalizedSiteTemplate, results: GenerationResultsHandler) {
        self.factory = factory
        self.results = results
    }

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

            let metadata = section.localized(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,
                page: section)
            content[.language] = language
            content[.contentClass] = "overview"
            content[.header] = makeHeader(page: section, metadata: metadata, language: language)
            content[.content] = makeContent(section: section, language: language)
            content[.footer] = results.getContentOfOptionalFile(at: section.additionalFooterContentPath, source: section.path)
            factory.page.generate(content, to: path, source: section.path)
    }

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

    private func makeHeader(page: Element, metadata: Element.LocalizedMetadata, language: String) -> String {
        let content = factory.makeHeaderContent(page: page, metadata: metadata, language: language)
        return factory.factory.centeredHeader.generate(content)
    }
}