# == About camping/fastcgi.rb
#
# Camping works very well with FastCGI, since your application is only loaded
# once -- when FastCGI starts.  In addition, this class lets you mount several
# Camping apps under a single FastCGI process, to help save memory costs.
#
# So where do you use the Camping::FastCGI class?  Use it in your application's
# postamble and then you can point your web server directly at your application.
# See Camping::FastCGI docs for more.
require 'camping'
require 'fcgi'

module Camping
# Camping::FastCGI is a small class for hooking one or more Camping apps up to
# FastCGI.  Generally, you'll use this class in your application's postamble.
#
# == The Smallest Example
#
#  if __FILE__ == $0
#    require 'camping/fastcgi'
#    Camping::FastCGI.start(YourApp)
#  end
#
# This example is stripped down to the basics.  The postamble has no database
# connection.  It just loads this class and calls Camping::FastCGI.start.
#
# Now, in Lighttpd or Apache, you can point to your app's file, which will
# be executed, only to discover that your app now speaks the FastCGI protocol.
#
# Here's a sample lighttpd.conf (tested with Lighttpd 1.4.11) to serve as example:
#
#   server.port                 = 3044
#   server.bind                 = "127.0.0.1"
#   server.modules              = ( "mod_fastcgi" )
#   server.document-root        = "/var/www/camping/blog/" 
#   server.errorlog             = "/var/www/camping/blog/error.log" 
#   
#   #### fastcgi module
#   fastcgi.server = ( "/" => ( 
#     "localhost" => ( 
#       "socket" => "/tmp/camping-blog.socket",
#       "bin-path" => "/var/www/camping/blog/blog.rb",
#       "check-local" => "disable",
#       "max-procs" => 1 ) ) )
#
# The file <tt>/var/www/camping/blog/blog.rb</tt> is the Camping app with
# the postamble.
#
# == Mounting Many Apps
#
#  require 'camping/fastcgi'
#  fast = Camping::FastCGI.new
#  fast.mount("/blog", Blog)
#  fast.mount("/tepee", Tepee)
#  fast.mount("/", Index)
#  fast.start
#
class FastCGI
    CHUNK_SIZE=(4 * 1024)

    attr_reader :mounts

    # Creates a Camping::FastCGI class with empty mounts.
    def initialize
        @mounts = {}
    end
    # Mounts a Camping application.  The +dir+ being the name of the directory
    # to serve as the application's root.  The +app+ is a Camping class.
    def mount(dir, app)
        dir.gsub!(/\/{2,}/, '/')
        dir.gsub!(/\/+$/, '')
        @mounts[dir] = app
    end

    # 
    # Starts the FastCGI main loop.
    def start(&blk)
        FCGI.each do |req|
            camp_do(req, &blk)
        end
    end

    # A simple single-app starter mechanism
    #
    #   Camping::FastCGI.start(Blog)
    #
    def self.start(app)
        cf = Camping::FastCGI.new
        cf.mount("/", app)
        cf.start
    end

    # Serve an entire directory of Camping apps. (See 
    # http://code.whytheluckystiff.net/camping/wiki/TheCampingServer.)
    #
    # Use this method inside your FastCGI dispatcher:
    #
    #   #!/usr/local/bin/ruby
    #   require 'rubygems'
    #   require 'camping/fastcgi'
    #   Camping::Models::Base.establish_connection :adapter => 'sqlite3', :database => "/path/to/db"
    #   Camping::FastCGI.serve("/home/why/cvs/camping/examples")
    # 
    def self.serve(path, index=nil)
        require 'camping/reloader'
        if File.directory? path
            fast = Camping::FastCGI.new
            script_load = proc do |script|
                app = Camping::Reloader.new(script)
                fast.mount("/#{app.mount}", app)
                app
            end
            Dir[File.join(path, '*.rb')].each &script_load
            fast.mount("/", index) if index

            fast.start do |dir, app|
                 Dir[File.join(path, dir, '*.rb')].each do |script|
                     smount = "/" + File.basename(script, '.rb')
                     script_load[script] unless fast.mounts.has_key? smount
                 end
            end
        else
            start(Camping::Reloader.new(path))
        end
    end

    private

    def camp_do(req)
        root, path, dir, app = "/"
        if ENV['FORCE_ROOT'] and ENV['FORCE_ROOT'].to_i == 1
            path = req.env['SCRIPT_NAME']
        else
            root = req.env['SCRIPT_NAME']
            path = req.env['PATH_INFO']
        end

        dir, app = @mounts.max { |a,b| match(path, a[0]) <=> match(path, b[0]) }
        unless dir and app
            dir, app = '/', Camping
        end
        yield dir, app if block_given?

        req.env['SERVER_SCRIPT_NAME'] = req.env['SCRIPT_NAME']
        req.env['SERVER_PATH_INFO'] = req.env['PATH_INFO']
        req.env['SCRIPT_NAME'] = File.join(root, dir)
        req.env['PATH_INFO'] = path.gsub(/^#{dir}/, '')

        controller = app.run(SeekStream.new(req.in), req.env)
        sendfile = nil
        headers = {}
        controller.headers.each do |k, v|
            if k =~ /^X-SENDFILE$/i and !ENV['SERVER_X_SENDFILE']
                sendfile = v
            else
                headers[k] = v
            end
        end

        body = controller.body
        controller.body = ""
        controller.headers = headers

        req.out << controller.to_s
        if sendfile
            File.open(sendfile, "rb") do |f|
                while chunk = f.read(CHUNK_SIZE) and chunk.length > 0
                    req.out << chunk
                end
            end
        elsif body.respond_to? :read
            while chunk = body.read(CHUNK_SIZE) and chunk.length > 0
                req.out << chunk
            end
            body.close if body.respond_to? :close
        else
            req.out << body.to_s
        end
    rescue Errno::EPIPE, EOFError 
    rescue SystemExit 
        raise 
    rescue Exception => exc
        req.out << server_error(root, path, exc, req)
    ensure
        req.finish
    end

    def server_error(root, path, exc, req)
        "Content-Type: text/html\r\n\r\n" +
        "<h1>Camping Problem!</h1>" +
        "<h2><strong>#{root}</strong>#{path}</h2>" + 
        "<h3>#{exc.class} #{esc exc.message}</h3>" +
        "<ul>" + exc.backtrace.map { |bt| "<li>#{esc bt}</li>" }.join + "</ul>" +
        "<hr /><p>#{req.env.inspect}</p>"
    end

    def match(path, mount)
        m = path.match(/^#{Regexp::quote mount}(\/|$)/)
        if m; m.end(0)
        else  -1
        end
    end

    def esc(str)
        str.gsub(/&/n, '&amp;').gsub(/\"/n, '&quot;').gsub(/>/n, '&gt;').gsub(/</n, '&lt;')
    end

    class SeekStream
        def initialize(stream)
            @last_read = ""
            @stream = stream
            @buffer = ""
        end
        def eof?
            @buffer.empty? && @stream.eof?
        end
        def each
            while true
                pull(1024) until eof? or @buffer.index("\n")
                return nil if eof?
                yield @buffer.slice!(0..(@buffer.index("\n") || -1))
            end
        end
        def pull(len)
            @buffer += @stream.read(len).to_s
        end
        def read(len = 16384)
            pull(len)
            @last_read =
                if eof?
                    nil
                else
                    @buffer.slice!(0...len)
                end
        end
        def seek(len, typ)
            raise NotImplementedError, "only IO::SEEK_CUR is supported with SeekStream" if typ != IO::SEEK_CUR
            raise NotImplementedError, "only rewinding is supported with SeekStream" if len > 0
            raise NotImplementedError, "rewinding #{-len} past the buffer #{@last_read.size} start not supported with SeekStream" if -len > @last_read.size
            @buffer = @last_read[len..-1] + @buffer
            @last_read = ""
            self
        end
    end

end
end