#!/usr/bin/env elixir

# Test script for network packagers
# Usage: elixir test_network_packagers.exs

defmodule NetworkPackagerTest do
  @moduledoc """
  Test script to verify VISA and MasterCard packagers work correctly
  """

  alias DaProductApp.MercuryISO8583.Packagers.{ISOMsg}
  alias DaProductApp.MercuryISO8583.Packagers.NetworkPackagers.{VisaPackager, MasterCardPackager}

  def run_tests do
    IO.puts("=== Network Packager Test Suite ===\n")
    
    test_visa_packager()
    test_mastercard_packager()
    test_routing_logic()
    
    IO.puts("\n=== All tests completed ===")
  end

  def test_visa_packager do
    IO.puts("Testing VISA Packager...")
    
    # Create a test purchase transaction
    visa_message = %ISOMsg{
      mti: "0200",
      fields: %{
        "2" => "4111111111111111",   # VISA PAN
        "3" => "000000",            # Processing code - purchase
        "4" => "000000010000",      # Transaction amount - $100.00
        "7" => "0110123456",        # Transmission date/time
        "11" => "123456",           # STAN
        "12" => "123456",           # Local time
        "13" => "1101",             # Local date
        "22" => "012",              # POS entry mode
        "25" => "00",               # POS condition code
        "32" => "123456",           # Acquiring institution ID
        "37" => "123456789012",     # Retrieval reference number
        "41" => "TERM0001",         # Terminal ID
        "42" => "MERCHANT00001",    # Merchant ID
        "49" => "840"               # Currency code - USD
      },
      dirty: false,
      max_field: 128
    }
    
    case VisaPackager.pack(visa_message) do
      {:ok, packed_data} ->
        IO.puts("  ✓ VISA pack successful, #{byte_size(packed_data)} bytes")
        
        case VisaPackager.unpack(packed_data) do
          {:ok, unpacked_message} ->
            IO.puts("  ✓ VISA unpack successful")
            verify_message_fields(visa_message, unpacked_message, "VISA")
          
          {:error, reason} ->
            IO.puts("  ✗ VISA unpack failed: #{inspect(reason)}")
        end
      
      {:error, reason} ->
        IO.puts("  ✗ VISA pack failed: #{inspect(reason)}")
    end
    
    IO.puts("")
  end

  def test_mastercard_packager do
    IO.puts("Testing MasterCard Packager...")
    
    # Create a test purchase transaction
    mc_message = %ISOMsg{
      mti: "0200",
      fields: %{
        "2" => "5555555555554444",   # MasterCard PAN
        "3" => "000000",            # Processing code - purchase
        "4" => "000000050000",      # Transaction amount - $500.00
        "7" => "0110123456",        # Transmission date/time
        "11" => "654321",           # STAN
        "12" => "123456",           # Local time
        "13" => "1101",             # Local date
        "22" => "012",              # POS entry mode
        "25" => "00",               # POS condition code
        "32" => "654321",           # Acquiring institution ID
        "37" => "210987654321",     # Retrieval reference number
        "41" => "TERM0002",         # Terminal ID
        "42" => "MERCHANT00002",    # Merchant ID
        "48" => "TEST_EBCDIC_DATA", # Special EBCDIC subfield data
        "49" => "840"               # Currency code - USD
      },
      dirty: false,
      max_field: 128
    }
    
    case MasterCardPackager.pack(mc_message) do
      {:ok, packed_data} ->
        IO.puts("  ✓ MasterCard pack successful, #{byte_size(packed_data)} bytes")
        
        case MasterCardPackager.unpack(packed_data) do
          {:ok, unpacked_message} ->
            IO.puts("  ✓ MasterCard unpack successful")
            verify_message_fields(mc_message, unpacked_message, "MasterCard")
          
          {:error, reason} ->
            IO.puts("  ✗ MasterCard unpack failed: #{inspect(reason)}")
        end
      
      {:error, reason} ->
        IO.puts("  ✗ MasterCard pack failed: #{inspect(reason)}")
    end
    
    IO.puts("")
  end

  def test_routing_logic do
    IO.puts("Testing BIN-based routing logic...")
    
    test_cases = [
      {"4111111111111111", :visa, "VISA card"},
      {"5555555555554444", :mastercard, "MasterCard"},
      {"2223000048400011", :mastercard, "MasterCard 2-series"},
      {"378282246310005", :amex, "American Express"},
      {"6011111111111117", :discover, "Discover"},
      {"1234567890123456", :unknown, "Unknown card type"}
    ]
    
    Enum.each(test_cases, fn {pan, expected_network, description} ->
      detected_network = determine_network_by_pan(pan)
      
      if detected_network == expected_network do
        IO.puts("  ✓ #{description}: #{pan} → #{detected_network}")
      else
        IO.puts("  ✗ #{description}: #{pan} → expected #{expected_network}, got #{detected_network}")
      end
    end)
    
    IO.puts("")
  end

  # Helper functions

  defp verify_message_fields(original, unpacked, network_name) do
    # Check that critical fields match
    critical_fields = ["2", "3", "4", "11", "37", "41", "42"]
    
    all_match = Enum.all?(critical_fields, fn field ->
      original_value = get_field_value(original, field)
      unpacked_value = get_field_value(unpacked, field)
      original_value == unpacked_value
    end)
    
    if all_match do
      IO.puts("  ✓ #{network_name} field verification passed")
    else
      IO.puts("  ✗ #{network_name} field verification failed")
      
      # Show mismatches
      Enum.each(critical_fields, fn field ->
        original_value = get_field_value(original, field)
        unpacked_value = get_field_value(unpacked, field)
        
        if original_value != unpacked_value do
          IO.puts("    Field #{field}: #{inspect(original_value)} → #{inspect(unpacked_value)}")
        end
      end)
    end
  end

  defp get_field_value(%ISOMsg{fields: fields}, field) do
    Map.get(fields, field)
  end

  defp determine_network_by_pan(pan) when is_binary(pan) and byte_size(pan) >= 4 do
    case pan do
      # VISA - starts with 4
      "4" <> _ -> :visa
      
      # MasterCard - starts with 5 or 2221-2720
      "5" <> _ -> :mastercard
      "2221" <> _ -> :mastercard
      "2222" <> _ -> :mastercard
      "2223" <> _ -> :mastercard
      "2224" <> _ -> :mastercard
      "2225" <> _ -> :mastercard
      "2226" <> _ -> :mastercard
      "2227" <> _ -> :mastercard
      
      # American Express - starts with 34 or 37
      "34" <> _ -> :amex
      "37" <> _ -> :amex
      
      # Discover - starts with 6011, 644-649, 65
      "6011" <> _ -> :discover
      "644" <> _ -> :discover
      "645" <> _ -> :discover
      "65" <> _ -> :discover
      
      _ -> :unknown
    end
  end

  defp determine_network_by_pan(_), do: :unknown
end

# Run the tests
NetworkPackagerTest.run_tests()