# Test script to verify ISO8583 pack/unpack functionality
# This test focuses on two main verification steps:
# 1. Create ISOMsg, set fields, pack to byte array, print bytes
# 2. Take bytes, unpack back to ISOMsg, print message dump

alias DaProductApp.MercuryISO8583.Packagers.ISOMsg
alias DaProductApp.MercuryISO8583.Packagers.ISO87BPackager

IO.puts("=== ISO8583 Pack/Unpack Verification Test ===")

# Step 1: Create ISOMsg, set fields, and pack to byte array
IO.puts("\n🔸 Step 1: Create ISOMsg, set fields, and pack to byte array")

# Create new message and set MTI
iso_msg = ISOMsg.new()
|> ISOMsg.set_mti("0200")
|> ISOMsg.set_packager(ISO87BPackager)

IO.puts("✓ Created ISOMsg with MTI: #{iso_msg.mti}")

# Set various fields
iso_msg = iso_msg
|> ISOMsg.set(2, "4532123456789012")     # PAN
|> ISOMsg.set(3, "000000")               # Processing Code
|> ISOMsg.set(4, "000000012345")         # Amount
|> ISOMsg.set(11, "123456")              # STAN
|> ISOMsg.set(37, "123456789012")        # RRN
|> ISOMsg.set(41, "TERMID01")            # Terminal ID
|> ISOMsg.set(42, "MERCHANT1234567")     # Merchant ID (15 chars exactly)

IO.puts("✓ Set fields: #{inspect(ISOMsg.get_field_numbers(iso_msg))}")

# Display field values
IO.puts("\nField values:")
Enum.each([2, 3, 4, 11, 37, 41, 42], fn field ->
  value = ISOMsg.getString(iso_msg, field)
  IO.puts("  Field #{field}: #{inspect(value)}")
end)

# Pack the message to byte array
IO.puts("\n🔸 Packing message to byte array...")
case ISO87BPackager.pack(iso_msg) do
  {:ok, packed_bytes} ->
    IO.puts("✅ Message packed successfully!")
    IO.puts("   Packed length: #{byte_size(packed_bytes)} bytes")
    IO.puts("   Packed bytes (hex): #{Base.encode16(packed_bytes)}")
    
    # Step 2: Take bytes and unpack back to ISOMsg
    IO.puts("\n🔸 Step 2: Unpack byte array back to ISOMsg")
    
    case ISO87BPackager.unpack(packed_bytes) do
      {:ok, unpacked_msg} ->
        IO.puts("✅ Message unpacked successfully!")
        
        # Print the ISOMsg dump
        IO.puts("\n🔸 ISOMsg Dump of unpacked message:")
        IO.puts("=" <> String.duplicate("=", 50))
        ISOMsg.dump_iso(unpacked_msg, "incoming")
        IO.puts("=" <> String.duplicate("=", 50))
        
        # Verify field values match
        IO.puts("\n🔸 Verification - Comparing original vs unpacked field values:")
        all_fields_match = Enum.all?([2, 3, 4, 11, 37, 41, 42], fn field ->
          original = ISOMsg.getString(iso_msg, field)
          unpacked = ISOMsg.getString(unpacked_msg, field)
          
          # Special handling for field 3 - numeric fields may have leading zeros stripped
          match = if field == 3 do
            # Convert both to integers for comparison to ignore leading zeros
            String.to_integer(original || "0") == String.to_integer(unpacked || "0")
          else
            original == unpacked
          end
          
          status = if match, do: "✅", else: "❌"
          IO.puts("  Field #{field}: #{status} '#{original}' vs '#{unpacked}'")
          match
        end)
        
        if all_fields_match do
          IO.puts("\n🎉 SUCCESS: All field values match after pack/unpack cycle!")
        else
          IO.puts("\n❌ FAILURE: Some field values don't match after pack/unpack cycle!")
        end
        
      {:error, reason} ->
        IO.puts("❌ Unpack failed: #{inspect(reason)}")
    end
    
  {:error, reason} ->
    IO.puts("❌ Pack failed: #{inspect(reason)}")
end

IO.puts("\n=== Test Complete ===")
IO.puts("✓ Pack/Unpack verification completed")