# SPDX-License-Identifier: Apache-2.0
# Copyright (C) 2021 OKTET Labs Ltd. All rights reserved.

#
# General CGI helpers
#

HEADER_FILE = "header.html"
FOOTER_FILE = "footer.html"

CURRENT_MONTH = "- Current -"
# Where to place it in the months list
CURRENT_MONTH_NUMBER = 0

def cgi_debug_log(msg)
    STDERR.puts "DEBUG: " + msg
end

class MyCGI < CGI

    # http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/23950?help-en
    def MyCGI::pretty(string, shift = "  ")
        i = 0; preserve = {}
        lines = string.gsub(/\n*<pre.*<\/pre>\n*/inm) {
            t = "%PRE#{i}"; i += 1
            preserve[t] = $&
            t
        }
        lines = lines.gsub(/\n*<textarea.*<\/textarea>\n*/inm) {
            t = "%TEXTAREA#{i}"; i += 1
            preserve[t] = $&
            t
        }
        lines = lines.gsub(/(?!\A)<(?:.|\n)*?>/n,
                           "\n\\0").gsub(/<(?:.|\n)*?>(?!\n)/n, "\\0\n")
        end_pos = 0
        while end_pos = lines.index(/^<\/(\w+)/n, end_pos)
            element = $1.dup
            start_pos = lines.rindex(/^\s*<#{element}/ni, end_pos)
            lines[start_pos ... end_pos] = "__" +
                lines[start_pos ...  end_pos].
                    gsub(/\n(?!\z)/n, "\n" + shift) +
                "__"
        end
        lines = lines.gsub(/^((?:#{Regexp::quote(shift)})*)__(?=<\/?\w)/n,
                           '\1')
        preserve.each { |t, s|
            lines.sub!(/#{Regexp::quote(t)}/, s)
        }
        lines
    end

    def MyCGI::list_select(list, param)
        param = Array.new if not param
        list.collect do |entry|
            param.include?(entry[0]) ? entry.dup.push(true) : entry
        end
    end

    def initialize(form_type, default_params, multiple_key, multiline_key, *args)
        super(*args)
        @form_type = form_type
        @tree_params = default_params
        @multiple_key = multiple_key
        @multiline_key = multiline_key
        self.params.each do |key, value|
                @tree_params = add_value(@tree_params, key, value, @multiple_key.include?(key))
        end
    end

    def add_value(hash, key, value, multiple)
        hash = Hash.new if not hash
        if /^(.*?):(.*)$/ =~ key
            hash[$1] = add_value(hash[$1], $2, value, @multiple_key.include?($1))
        elsif @multiline_key.include?(key)
            hash[key] = value.join
        else
            hash[key] = (multiple or value.length > 1) ? value : value[0]
        end
        hash
    end

    def hiddens(value)
        value.inject([]) do |res, item|
            res + [Amrita.a(:name => item[0], :value => item[1])]
        end
    end

    # Create array of pairs [name, value] from the parameters subtree
    def tree_flatten(keys)
        hash = @tree_params
        keys.each do |key|
            return [] if not hash[key]
            hash = hash[key]
        end
        add_flatten(keys[0..-2], keys[-1], hash)
    end

    def add_flatten(prefix, field, data)
        names = field ? prefix + [field] : prefix
        if data.is_a? Hash
            data.inject([]) do |res, pair|
                res + add_flatten(names, pair[0], pair[1])
            end
        elsif data.is_a? Array
            data.inject([]) do |res, value|
                res << [names.join(":"), value.to_s]
            end
        else
            # single value
            [[names.join(":"), data.to_s]]
        end
    end

    def tree_hidden(keys)
        hash = @tree_params
        keys.each do |key|
            return "" if not hash[key]
            hash = hash[key]
        end
        add_hidden(keys[0..-2], keys[-1], hash)
    end

    def MyCGI::list_options(data, selections = nil)
        selection = ((selections.is_a? Array) ? selections[0] : selections).to_s
        data.collect do |pair|
            item = Amrita.a(:value => pair[0]){ pair[1] }
            item << Amrita.a(:selected => "selected")[0] if
                pair[0].to_s == selection
            item
        end
    end

    def tree_hidden_e(keys)
        hash = @tree_params
        keys.each do |key|
            return [] if not hash[key]
            hash = hash[key]
        end
        add_hidden_e(keys[0..-2], keys[-1], hash)
    end

    def add_hidden_e(prefix, field, value)
        if value.is_a? Hash
            value.inject([]) do |res, pair|
                res + add_hidden_e(prefix + [field], pair[0], pair[1])
            end
        else
            value.inject([]) do |res, value1|
                res + [ Amrita.a(:name => (prefix + [field]).join(":"),
                               :value => value1) ]
            end
        end
    end

    def add_hidden(prefix, field, value)
        if value.is_a?Hash
            value.inject("") do |res, pair|
                res + add_hidden(prefix + [field], pair[0], pair[1])
            end
        else
            value.inject("") do |res, value1|
                res + hidden((prefix + [field]).join(":"), value1)
            end
        end
    end

    def MyCGI::hash2date(hash)
        begin
            value = %w(year month day).collect do |p|
                    hash[p].is_a?(Array) ? hash[p][0] : hash[p]
                    end
            value[0] = case value[0]
                       when '$' then 9999
                       when '#' then Date.today.year
                       else value[0].to_i
                       end
            value[1] = case value[1]
                       when '$' then Date::MONTHNAMES.length - 1
                       when CURRENT_MONTH then Date.today.month
                       when CURRENT_MONTH_NUMBER.to_s then Date.today.month
                       else value[1].to_i
                       end

            if value[2] == '$'
                value[2] = 1
                (Date.new(*value) >> 1) - 1
            elsif value[2] == '#'
                value[2] = Date.today.day
                Date.new(*value)
            else
                value[2] = value[2].to_i
                Date.new(*value)
            end
        rescue ArgumentError
            raise "Invalid date #{hash["year"]}-#{hash["month"]}-#{hash["day"]}"
        end
    end
    def MyCGI::date2hash(date)
        {
            "year" => [date.year.to_s],
            "month" => [date.mon.to_s],
            "day" => [date.day.to_s]
        }
    end

    def MyCGI::select_date(prefix = "", value = nil, edit = false)
        if value == nil
            edit = true
            value = MyCGI::date2hash(Date.today)
        elsif value.is_a?Hash
            # TODO: !!!!
            value = { "year" => [value["year"]],
                      "month" => [value["month"]],
                      "day" => [value["day"]] } unless value["year"].is_a?Array
            edit = true
        else
            value = MyCGI::date2hash(value)
        end
        if edit
            template = Amrita::TemplateText.new(
                "<input class='form-control' id='day' size='2' type='text'>
                 <select class='form-control' id='month'><option id='item'></select>
                 <input class='form-control' id='year' size='4' type='text'>")
            template.asxml = true
            s = String.new
            template.expand(s,
                {:day => Amrita.a(
                    :name => prefix + ":day",
                    :value => value["day"][0]),
                 :month => Amrita.a(
                     :name => prefix + ":month"){
                     {:item => list_options(
                          (0..(Date::MONTHNAMES.length - 1)).collect do |m|
                              case m
                              when CURRENT_MONTH_NUMBER then [m.to_s, CURRENT_MONTH]
                              else [m.to_s, Date::MONTHNAMES[m]]
                              end
                          end, value["month"][0])
                      }
                      },
                 :year => Amrita.a(
                     :name => prefix + ":year",
                     :value => value["year"][0])
                 })
            s
        else
            d = Date.new(value["year"][0].to_i, value["month"][0].to_i,
                         value["day"][0].to_i)
            sprintf("%s %s %s (%s)", value["day"][0],
                    Date::MONTHNAMES[value["month"][0].to_i],
                    value["year"][0],
                    Date::ABBR_DAYNAMES[d.wday])
        end
    end

    def MyCGI::select_date_e(prefix = "", value = nil, edit = false)
        noescape{ select_date(prefix, value, edit) }
    end

    # Assign values to the all-site common parts of the page
    #
    # @param data  Hash of data for amrita template of the page
    def MyCGI::add_commons(data)
        data[:header] = noescape{ File.open(HEADER_FILE) { |f| f.read }}
        data[:footer] = noescape{ File.open(FOOTER_FILE) { |f| f.read }}
    end

    def MyCGI::optional(data)
        { :value => data }
    end

    # Create string from the 'value' that can be used
    # as a value of HTML DOM attribute 'id'
    #
    # @return String of proposed attribute value
    def MyCGI::element_id(value)
        id = value.to_s
        if id.empty? or id !~ /[A-Za-z].*/
            "s" + id
        else
            id
        end
    end

    def MyCGI.dump(value)
        case value.class.to_s
        when "Hash" then
            "{" + value.collect do |key, x|
                "#{key} => #{dump(x)}"
            end.join(", ") + "}"
        when "String" then
            "\"#{value}\""
        when "Array" then
            "[#{value.collect {|x| dump(x)}.join(",")}]"
        else
            "#{value.class}(#{value.to_s})"
        end
    end

    attr_accessor :form_type, :tree_params, :multiple_key
    private :add_value
end