#!/usr/bin/env elixir

# Start the application dependencies
{:ok, _} = Application.ensure_all_started(:logger)

# Start the Mix project to load dependencies
Mix.start()
Mix.env(:dev)
Code.eval_file("mix.exs")

# Load dependencies
{:ok, _} = Application.ensure_all_started(:iso_8583)

# Compile the modules we need
Code.compile_file("lib/da_product_app/switch/message_handler.ex")

alias DaProductApp.Switch.MessageHandler

defmodule MessageHandlerTest do
  require Logger

  def test_mercury_tpdu_parsing do
    Logger.info("Testing Mercury TPDU message parsing...")
    
    # Test data: Mercury TPDU (6000782000) + binary ISO8583 message
    # TPDU: 6000782000 (5 bytes)
    # ISO8583: Binary format starting with MTI 0400
    message_payload = <<
      0x60, 0x00, 0x78, 0x20, 0x00,  # Mercury TPDU
      0x04, 0x00,                    # MTI 0400 in BCD
      0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  # Primary bitmap
      0x00, 0x00, 0x00, 0x00, 0x01, 0x23, 0x45, 0x67,  # Fields data
      0x89, 0xAB, 0xCD, 0xEF, 0x00, 0x01, 0x02, 0x03,
      0x04, 0x05, 0x06, 0x07, 0x08, 0x09
    >>
    
    # Create proper length header
    length = byte_size(message_payload)
    test_data = <<length::16-big>> <> message_payload
    
    Logger.info("Test data (#{byte_size(test_data)} bytes): #{Base.encode16(test_data)}")
    Logger.info("Message payload length: #{length} bytes")
    
    case MessageHandler.parse(test_data) do
      {:ok, result, _remaining} ->
        Logger.info("✅ Parse successful!")
        Logger.info("Result: #{inspect(result)}")
        
        # Check if TPDU was preserved
        case Map.get(result, :tpdu) do
          nil ->
            Logger.info("❌ TPDU context not preserved")
          tpdu ->
            Logger.info("✅ TPDU preserved: #{Base.encode16(tpdu)}")
        end
        
      {:error, reason} ->
        Logger.error("❌ Parse failed: #{inspect(reason)}")
        
      {:incomplete, _} ->
        Logger.info("⚠️  Message incomplete")
    end
  end

  def test_binary_data_analysis do
    Logger.info("Testing binary data analysis...")
    
    # Just the ISO8583 part without TPDU (for analysis)
    iso8583_binary = <<
      0x04, 0x00,                    # MTI 0400 in BCD
      0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  # Primary bitmap
      0x00, 0x00, 0x00, 0x00, 0x01, 0x23, 0x45, 0x67,  # Fields data
      0x89, 0xAB, 0xCD, 0xEF, 0x00, 0x01, 0x02, 0x03,
      0x04, 0x05, 0x06, 0x07, 0x08, 0x09
    >>
    
    Logger.info("Binary ISO8583 data: #{Base.encode16(iso8583_binary)}")
    
    # Test each decode strategy individually
    <<mti_bytes::binary-size(2), rest::binary>> = iso8583_binary
    Logger.info("MTI bytes: #{Base.encode16(mti_bytes)} (#{inspect(mti_bytes)})")
    
    # BCD conversion test
    case mti_bytes do
      <<high_nibble::4, low_nibble::4, high_nibble2::4, low_nibble2::4>> ->
        ascii_mti = "#{high_nibble}#{low_nibble}#{high_nibble2}#{low_nibble2}"
        Logger.info("BCD to ASCII MTI: #{ascii_mti}")
      _ ->
        Logger.info("❌ BCD conversion failed")
    end
    
    # Full hex conversion test
    hex_string = Base.encode16(iso8583_binary)
    Logger.info("Full hex conversion: #{String.slice(hex_string, 0, 50)}...")
  end

  def run_all_tests do
    Logger.info("=== Starting Message Handler Tests ===")
    test_binary_data_analysis()
    Logger.info("")
    test_mercury_tpdu_parsing()
    Logger.info("=== Tests Complete ===")
  end
end

MessageHandlerTest.run_all_tests()