require 'sinatra'
require 'sinatra/contrib'

REGEXP = {
    php:    'echo\s([0-9]+)\s?\+\s?([0-9]+);',
    perl:   'print\s([0-9]+)\s?\+\s?([0-9]+);',
    python: 'print\s([0-9]+)\s?\+\s?([0-9]+)$',
    asp:    'Response.Write\(\s?([0-9]+)\s?\+\s?([0-9]+)\s?\)'
}

def exec( lang, str, prefix = nil, postfix = nil )
    return if !str

    r = ''
    r << Regexp.escape( prefix ) if prefix
    r << '^' if !(prefix || postfix)
    r << REGEXP[lang]
    r << Regexp.escape( postfix ) if postfix

    x, y = str.scan( Regexp.new( r ) ).flatten
    (x && y) ? Integer( x ) + Integer( y ) : nil
end

def variations
    @@v ||= [ '', ';%s', "\";%s#", "';%s#" ]
end

def get_variations( lang, str )
    variations.map do |v|
        pre, post = v.split( '%s' )
        exec( lang, str, pre, post )
    end.compact.to_s
end

REGEXP.keys.each do |language|
    language_str = language.to_s

    get '/' + language_str do
        <<-EOHTML
            <a href="/#{language_str}/link?input=default">Link</a>
            <a href="/#{language_str}/form">Form</a>
            <a href="/#{language_str}/cookie">Cookie</a>
            <a href="/#{language_str}/header">Header</a>
        EOHTML
    end

    get "/#{language_str}/link" do
        <<-EOHTML
            <a href="/#{language_str}/link/straight?input=default">Link</a>
            <a href="/#{language_str}/link/append?input=default">Link</a>
        EOHTML
    end

    get "/#{language_str}/link/straight" do
        default = 'default'
        return if params['input'].start_with?( default )

        get_variations( language, params['input'] )
    end

    get "/#{language_str}/link/append" do
        default = 'default'
        return if !params['input'].start_with?( default )

        get_variations( language, params['input'].split( default ).last )
    end

    get "/#{language_str}/form" do
        <<-EOHTML
            <form action="/#{language_str}/form/straight" method='post'>
                <input name='input' value='default' />
            </form>

            <form action="/#{language_str}/form/append">
                <input name='input' value='default' />
            </form>
        EOHTML
    end

    post "/#{language_str}/form/straight" do
        default = 'default'
        return if !params['input'] || params['input'].start_with?( default )

        get_variations( language, params['input'] )
    end

    get "/#{language_str}/form/append" do
        default = 'default'
        return if !params['input'] || !params['input'].start_with?( default )

        get_variations( language, params['input'].split( default ).last )
    end


    get "/#{language_str}/cookie" do
        <<-EOHTML
            <a href="/#{language_str}/cookie/straight">Cookie</a>
            <a href="/#{language_str}/cookie/append">Cookie</a>
        EOHTML
    end

    get "/#{language_str}/cookie/straight" do
        default = 'cookie value'
        cookies['cookie'] ||= default
        return if cookies['cookie'].start_with?( default )

        get_variations( language, cookies['cookie'] )
    end

    get "/#{language_str}/cookie/append" do
        default = 'cookie value'
        cookies['cookie2'] ||= default
        return if !cookies['cookie2'].start_with?( default )

        get_variations( language, cookies['cookie2'].split( default ).last )
    end

    get "/#{language_str}/header" do
        <<-EOHTML
            <a href="/#{language_str}/header/straight">Cookie</a>
            <a href="/#{language_str}/header/append">Cookie</a>
        EOHTML
    end

    get "/#{language_str}/header/straight" do
        default = 'arachni_user'
        return if env['HTTP_USER_AGENT'].start_with?( default )

        get_variations( language, env['HTTP_USER_AGENT'] )
    end

    get "/#{language_str}/header/append" do
        default = 'arachni_user'
        return if !env['HTTP_USER_AGENT'].start_with?( default )

        get_variations( language, env['HTTP_USER_AGENT'].split( default ).last )
    end

end