package arbitrum

import (
	"crypto/rand"
	"encoding/hex"
	"testing"

	"github.com/fraktal/mev-beta/pkg/calldata"
)

// FuzzABIDecoder ensures the swap decoder tolerates arbitrary calldata without panicking.
func FuzzABIDecoder(f *testing.F) {
	decoder, err := NewABIDecoder()
	if err != nil {
		f.Fatalf("failed to create ABI decoder: %v", err)
	}

	// Seed with known selectors (Uniswap V2/V3 multicall patterns)
	f.Add([]byte{0xa9, 0x05, 0x9c, 0xbb})
	f.Add([]byte{0x41, 0x4b, 0xf3, 0x89})
	f.Add([]byte{0x18, 0xcb, 0xaf, 0xe5})

	// Seed with random data of reasonable length
	random := make([]byte, 64)
	_, _ = rand.Read(random)
	f.Add(random)

	f.Fuzz(func(t *testing.T, data []byte) {
		defer func() {
			if r := recover(); r != nil {
				t.Fatalf("DecodeSwapTransaction panicked for %x: %v", data, r)
			}
		}()

		if len(data) == 0 {
			data = []byte{0x00}
		}

		hexPayload := "0x" + hex.EncodeToString(data)
		if _, err := decoder.DecodeSwapTransaction("generic", hexPayload); err != nil {
			t.Logf("decoder returned expected error: %v", err)
		}
	})
}

// FuzzMulticallExtractor validates robustness of multicall token extraction.
func FuzzMulticallExtractor(f *testing.F) {
	seed := make([]byte, 96)
	copy(seed[:4], []byte{0xac, 0x96, 0x50, 0xd8})
	f.Add(seed)

	random := make([]byte, 128)
	_, _ = rand.Read(random)
	f.Add(random)

	f.Fuzz(func(t *testing.T, params []byte) {
		defer func() {
			if r := recover(); r != nil {
				t.Fatalf("ExtractTokensFromMulticall panicked for %x: %v", params, r)
			}
		}()

		if _, err := calldata.ExtractTokensFromMulticall(params); err != nil {
			t.Logf("multicall extraction reported error: %v", err)
		}
	})
}