# Nick's web site: css_source filter.  Add a notice to generated CSS
# files where the reader may find the source code.
#
# Copyright © 2020 Nick Bowler
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

class CssSourceFilter < Nanoc::Filter
    identifier :css_source

    def run(content, params = {})
        srcuri = if params[:uribase]
            then params[:uribase] + item_source(@item) end
        copypattern = /\/\*.*?[Cc]opyright.*?\*\//m
        css = content.gsub(copypattern, "")
        css.gsub!(/^@charset.*?$\n?/m, "")

        begin
            copymsgs = @item.compiled_content(snapshot: :css_source)
        rescue Nanoc::Core::Errors::NoSuchSnapshot
            copymsgs = content
        end
        copymsgs = copymsgs.scan(copypattern)

        ["/*",
         " * Generated file, do not edit!",
         " * Compiled from " + item_source(@item) + " on " +
            Time.now.gmtime.strftime("%Y-%m-%d %H:%M UTC"),
         if srcuri then
            " * Source code is available online at <" + srcuri + ">"
         end, "*/", copymsgs, css].compact.join("\n")
    end
end