# XHTML generation
# Copyright (C) 2023  Nguyễn Gia Phong
#
# This file if part of hybring.
#
# Hybring is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Hybring is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with hybring.  If not, see <https://www.gnu.org/licenses/>.

require "xml"

CSS = "
      html {
          margin: auto;
          max-width: 72ch;
      }
      body { margin-bottom: 2rem }
      h1, h2, h3, h4, h5, h6 { margin: 1ex 0 }
      form {
          display: grid;
          grid-template-columns: max-content 1fr 0;
      }
      form label { margin-right: 1ch }
      form input { margin-bottom: 1ex }
      .error { color: red }
    "

def criteria(xml)
  xml.element "h2" do xml.text "criteria" end
  xml.element "p" do
    xml.text "We accept pretty much any site"
    xml.text " served under an OpenNIC domain"
    xml.text " meeting the following requirements."
  end
  xml.element "ul" do
    xml.element "li" do xml.text "Family-friendly content" end
    xml.element "li" do xml.text "No violence incitation or doxing" end
    xml.element "li" do xml.text "No user tracking" end
    xml.element "li" do
      xml.text "ICANN counterpart accessible via HTTPS"
    end
    xml.element "li" do
      xml.text "Both linking to neighboring members"
    end
  end
  xml.element "p" do
    xml.text "Note that the two sites needn't be the same, as long as"
    xml.text " they represent the same entity, e.g. person or organization."
    xml.text "  The clear net site is for serving visitors"
    xml.text " without OpenNIC access or preferring secure connections."
  end
end

def input(xml, name, label, hint, error, value)
  if error
    xml.element "span"
    xml.element "span", class: "error" do xml.text error end
  end
  xml.element "label", for: name do xml.text label end
  xml.element "input", name: name, placeholder: hint, value: value,
              required: "required"
end

def form(xml, errors = {} of String => String,
         params = {} of String => String)
  # FIXME: get URL from configuration
  xml.element "form", action: "http://127.0.0.1:8080", method: "POST" do
    input xml, "nick", "Nickname", "digits and lowercase letters",
      errors.fetch("nick", nil), params.fetch("nick", nil)
    input xml, "opennic", "OpenNIC URL", "e.g. http://example.null",
      errors.fetch("opennic", nil), params.fetch("opennic", nil)
    input xml, "icann", "ICANN URL", "e.g. https://example.net",
      errors.fetch("icann", nil), params.fetch("icann", nil)
    xml.element "span"
    xml.element "input", type: "submit", value: "Let me in!"
  end
end

def member(xml, nick, opennic, icann, feed? = false)
  xml.element "p" do
    xml.text "The following membership is pending for approval."
    xml.text "  Please subscribe to the "
    # FIXME: get base URL from configuration
    xml.element "a", href: "http://127.0.0.1:42069/#{nick}.atom" do
        xml.text "web feed"
    end
    xml.text " for further instructions."
  end if feed?
  xml.element "h3" do xml.text nick end
  xml.text "OpenNIC: "
  xml.element "a", href: opennic do xml.text opennic end
  xml.element "br"
  xml.text "ICANN: "
  xml.element "a", href: icann do xml.text icann end
  xml.element "br"
end

def page(errors = {} of String => String,
         params = {} of String => String) : String
  XML.build encoding: "UTF-8", indent: "  " do |xml|
    xml.element "html", xmlns: "http://www.w3.org/1999/xhtml", lang: "en" do
      xml.element "head" do
        xml.element "meta", name: "viewport",
                    content: "width=device-width,initial-scale=1.0"
        xml.element "link", rel: "icon", href: "data:,"
        xml.element "style" do xml.text CSS end
        xml.element "title" do xml.text "le cercle libre" end
      end
      xml.element "body" do
        xml.element "h1" do xml.text "le cercle libre" end
        xml.element "p" do
          xml.text "The Free Circle is a web ring for sites"
          xml.text " with an OpenNIC domain."
        end
        criteria xml

        xml.element "h2" do xml.text "joining" end
        # FIXME: query database for this
        left = right = "http://cercle.libre"
        if params.empty? # static page
          xml.element "p" do
            xml.text "First, add "
            xml.element "a",
                        href: "https://html.spec.whatwg.org/#the-a-element" do
                xml.text "anchors"
            end
            xml.text " refering to the following neighbors to your sites"
            xml.text " on both OpenNIC and ICANN domains."
            xml.text "  Your neighbors will change as people come and go,"
            xml.text " so you will be given an Atom feed with instructions"
            xml.text " to keep the hyperlinks up to date."
          end
          xml.element "ul" do
            xml.element "li" do
              xml.text "Left: "
              xml.element "a", href: left do xml.text left end
            end
            xml.element "li" do
              xml.text "Right: "
              xml.element "a", href: right do xml.text right end
            end
          end

          xml.element "p" do
            xml.text "Then, please fill out the form below."
          end
          form xml
          xml.element "h2" do xml.text "members" end
          # FIXME: query database for this
          member xml, "self", "http://cercle.libre", "https://khoanh.loang.net"
        elsif errors.empty?
          member xml, params["nick"], params["opennic"], params["icann"], true
        else
          form xml, errors, params
        end
      end
    end
  end
end