require "process"
require "io"
require "socket"

require "./config"

at_exit { GC.collect }

module Taro

  enum MsgType : UInt8
    MBOX_LIST
    GET_MBOX
    MAIL_LIST
    MARK_ALL_READ
    SEARCH_MAIL = 5
    REFILE_MAIL = 7
    TRASH_MAIL = 9
    READ_MAIL = 11
    COMPOSE_MAIL = 13
    UPDATE_UI = 15
  end

  MSG_SIZES = {
    MsgType::MBOX_LIST => 4096_u16,
    MsgType::MAIL_LIST => 32768_u16,
  }

  def u8arr_tou16(s : Slice(UInt8)) : UInt16
    if s.size < 2
      return 0_u16
    else
      low : UInt16 = UInt16.new(s[0])*256
      high : UInt16 = UInt16.new(s[1])
      return low + high
    end
  end

  enum WinType
    LIST
    READER
    COMPOSE
  end
  
  class Mesg
    @type : MsgType
    @data : Slice(UInt8)
    
    def type
      @type
    end
    
    def data
      @data
    end
    
    def initialize(@type, @data)
    end
  end

  class ChildWindow
    include Taro
  
    @@msg : Channel(Mesg) = Channel(Mesg).new
    
    def self.msg
      @@msg
    end

    @lifetime : Channel(UInt8)
    @stdout_w : IO::FileDescriptor
    @stdout_r : IO::FileDescriptor
    @stdin_w : IO::FileDescriptor 
    @stdin_r : IO::FileDescriptor 
    @decoding : Bool = false
    @sizing : Bool = false
    @szshort : UInt16 = 0
    
    def initialize(w : WinType = WinType::LIST, arg : String = "")
      @stdout_r, @stdout_w = IO.pipe
      @stdin_r, @stdin_w = IO.pipe
      @lifetime = Channel(UInt8).new
      
      case w
      when WinType::LIST then
        spawn do
          Process.run(
            command: "#{TARO_LIB}/#{UXN_EMU}",
            args: [ "taro-ls" ],
            chdir: TARO_LIB, 
            input: @stdin_r, 
            output: @stdout_w, 
            error: Process::Redirect::Inherit)
          @lifetime.send(0)
        end
        spawn do
          loop do
            @@msg.send(read_msg)
          end
        end
      when WinType::READER then
        spawn do
          Process.run(command: READER_PROG + " " + arg, shell: true)
          @@msg.send(Mesg.new(MsgType::UPDATE_UI, Slice(UInt8).new(0)))
        end
      when WinType::COMPOSE then
        spawn do
          Process.run(command: COMPOSE_PROG, shell: true)
          @@msg.send(Mesg.new(MsgType::UPDATE_UI, Slice(UInt8).new(0)))
        end
      end
          
    end
    
    def lifetime
      @lifetime
    end
    
    def write_msg(msgtype : MsgType, data : Slice)
      msgsz = UInt16.new(data.size > MSG_SIZES[msgtype] ? MSG_SIZES[msgtype] : data.size)
      msgtype.value.to_io(@stdin_w, IO::ByteFormat::BigEndian)
      msgsz.to_io(@stdin_w, IO::ByteFormat::BigEndian)
      
      if msgsz == MSG_SIZES[msgtype]
        @stdin_w.write(data[0..msgsz - 2])
        10_u8.to_io(@stdin_w, IO::ByteFormat::BigEndian)
      elsif msgsz != 0
        @stdin_w.write(data[0..msgsz - 1])
      end
    end
    
    def read_msg
      msgType : MsgType = MsgType::MBOX_LIST
      data : Slice(UInt8) = Slice(UInt8).new(0)
      loop do
        if @stdout_r.closed?
          @decoding = false
          @sizing = false
          @szshort = 0
          break
        end
        if !@decoding
          msgType = MsgType.new(@stdout_r.read_byte || 0_u8)
          @decoding = true
          @sizing = true
        elsif @sizing
          szslice = Slice(UInt8).new(2)
          @stdout_r.read_fully(szslice)
          @szshort = u8arr_tou16(szslice)
          @sizing = false
          if @szshort == 0
            @decoding = false
            break
          end
        else
          slc = Slice(UInt8).new(@szshort)
          @stdout_r.read_fully(slc)
          data = slc
          @decoding = false
          @szshort = 0
          break
        end
      end
      return Mesg.new(msgType, data)
    end

  end
  
  class CappedIO < IO::Memory
    def write(slice : Bytes)
      if slice.size >= MSG_SIZES[MsgType::MAIL_LIST]
        super(slice[0..MSG_SIZES[MsgType::MAIL_LIST] - 1])
      else
        super(slice)
      end
    end
  end
  
  class MblazeProxy
    @@mailbox : String = "INBOX"
    @@search_regex : String = ""
  
    def self.mailbox
      @@mailbox
    end
    
    def self.search_regex
      @@search_regex
    end
    
    private def run_cmd(cmdtxt : String) : IO::Memory
      io = CappedIO.new
      Process.run(cmdtxt, shell: true, output: io)
      return io
    end
  
    def list_mail : IO::Memory
      if @@search_regex != ""
        return search_mail(@@search_regex, false, false)
      end
      cmd = "
        mbox=#{MBOX_ROOT}/#{@@mailbox}
    
        mdirs ${mbox} | xargs minc > /dev/null
        mlist ${mbox} | msort -dr | mseq -S | mscan"

      return run_cmd(cmd)
    end
    
    def list_mboxes : IO::Memory
      cmd = "echo 'INBOX' ; for x in $(mdirs -a #{MBOX_ROOT} | sort | grep -v INBOX); do echo ${x##{MBOX_ROOT}/}; done"
    
      return run_cmd(cmd)
    end
    
    def mark_all_read
      cmd = "mflag -S :"
      run_cmd(cmd)
    end
    
    def set_mbox(box : String)
      @@mailbox = box
      @@search_regex = ""
    end
    
    def trash_mail(range_start : UInt16, range_end : UInt16)
      cmd = "mrefile #{range_start}:#{range_end} #{MBOX_ROOT}/Trash"
      
      # destroy mail if we are trashing what's already in the trash!
      if @@mailbox == "Trash"
        cmd = "for x in $(mseq #{range_start}:#{range_end}); do rm $x; done"
      end
      run_cmd(cmd)
    end
    
    def refile_mail(range_start : UInt16, range_end : UInt16, to_mbox : String)
      canonical_mbox = run_cmd("readlink -f '#{MBOX_ROOT}/#{to_mbox.gsub("'", "\'")}'").to_s
      
      # if readlink is not available, fall back to what the user gave :shrug:
      if canonical_mbox.empty?
        canonical_mbox = "#{MBOX_ROOT}/#{to_mbox}"
      end
      
      if canonical_mbox.starts_with?(MBOX_ROOT)
        cmd = "mrefile #{range_start}:#{range_end} #{canonical_mbox.gsub(" ", "\ ").gsub("\"", "\\\"").gsub("'", "\'")}"
        run_cmd(cmd)
      end
    end
    
    def search_mail(query : String, body : Bool, case_sensitive : Bool) : IO::Memory
      query = query.gsub("'", "\'")
      @@search_regex = query
      cmd = "mlist #{MBOX_ROOT}/#{@@mailbox} | magrep #{case_sensitive ? "" : "-i"} #{body ? "/" : "*"}:'#{query}' | msort -dr | uniq | mseq -S | mscan"
      return run_cmd(cmd)
    end
  end

  class TaroCtl
  
    include Taro
  
    @mblaze : MblazeProxy
    @lsWin : ChildWindow
    @socket : UNIXServer
  
    def initialize
      @lsWin = ChildWindow.new
      @mblaze = MblazeProxy.new
      
      File.delete?("#{TARO_LIB}/taro.sock")
      @socket = UNIXServer.new("#{TARO_LIB}/taro.sock")
      
      list = @mblaze.list_mail
      mboxes = @mblaze.list_mboxes
      @lsWin.write_msg(MsgType::MBOX_LIST, mboxes.to_slice)
      @lsWin.write_msg(MsgType::MAIL_LIST, list.to_slice)
    end
    
    def run
      spawn do
        while client = @socket.accept?
          spawn do
            b = Slice(UInt8).new(1)
            client.read(b)
            ChildWindow.msg.send(Mesg.new(MsgType::UPDATE_UI, Slice(UInt8).new(0)))
          end
        end
      end

      loop do
        select
        when @lsWin.lifetime.receive?
          @socket.close
          exit
        when m = ChildWindow.msg.receive
          case m.type
          when MsgType::GET_MBOX then
            @mblaze.set_mbox(String.new(m.data))
            @lsWin.write_msg(MsgType::MAIL_LIST, @mblaze.list_mail.to_slice)
          when MsgType::MARK_ALL_READ then
            @mblaze.mark_all_read
            @lsWin.write_msg(MsgType::MAIL_LIST, @mblaze.list_mail.to_slice)
          when MsgType::SEARCH_MAIL then
            search_results = @mblaze.search_mail(String.new(m.data), false, false)
            @lsWin.write_msg(MsgType::MAIL_LIST, search_results.to_slice)
          when MsgType::REFILE_MAIL then
            range_start = u8arr_tou16(m.data[0..1])
            range_end = u8arr_tou16(m.data[2..3])
            dest_mbox = String.new(m.data[4..])
            @mblaze.refile_mail(range_start, range_end, dest_mbox)
            @lsWin.write_msg(MsgType::MAIL_LIST, @mblaze.list_mail.to_slice)
          when MsgType::TRASH_MAIL then
            range_start = u8arr_tou16(m.data[0..1])
            range_end = u8arr_tou16(m.data[2..3])
            @mblaze.trash_mail(range_start, range_end)
            @lsWin.write_msg(MsgType::MAIL_LIST, @mblaze.list_mail.to_slice)
          when MsgType::READ_MAIL then
            mmsg = u8arr_tou16(m.data[0..1])
            ChildWindow.new(WinType::READER, mmsg.to_s)
          when MsgType::COMPOSE_MAIL then
            ChildWindow.new(WinType::COMPOSE)
          when MsgType::UPDATE_UI then
            @lsWin.write_msg(MsgType::MAIL_LIST, @mblaze.list_mail.to_slice)
          end
        end
      end
    end

  end

end

taro = Taro::TaroCtl.new
taro.run