import Foundation

struct PrefilledTopBarTemplate {

    let language: String

    let sections: [SectionInfo]

    let topBarWebsiteTitle: String

    private let topBar: TopBarTemplate

    init(template: TopBarTemplate, language: String, sections: [SectionInfo], topBarWebsiteTitle: String) throws {
        self.topBar = template
        self.language = language
        self.sections = sections
        self.topBarWebsiteTitle = topBarWebsiteTitle
    }

    func generate(section: String?, languageButton: String?) -> String {
        var content = [TopBarTemplate.Key : String]()
        content[.title] = topBarWebsiteTitle
        content[.titleLink] = topBarWebsiteTitle(language: language)
        content[.elements] = elements(activeSection: section)
        content[.languageButton] = languageButton.unwrapped(topBarLanguageButton) ?? ""
        return topBar.generate(content)
    }

    private func elements(activeSection: String?) -> String {
        sections
            .map {
                topBarNavigationLink(url: $0.url, text: $0.name, isActive: activeSection == $0.id)
            }
            .joined(separator: "\n")
    }

    #warning("Move HTML code to single location")
    private func topBarWebsiteTitle(language: String) -> String {
        "/\(language).html"
    }

    private func topBarLanguageButton(_ language: String) -> String {
        "<a href=\"\(language).html\">\(language)</a>"
    }

    private func topBarNavigationLink(url: String, text: String, isActive: Bool) -> String {
        "<a\(isActive ? " class=\"active\"" : "") href=\"/\(url)\">\(text)</a>"
    }

    struct SectionInfo {

        let id: String

        let name: String

        let url: String
    }
}