package discovery

import (
	"testing"

	"github.com/ethereum/go-ethereum/common"
	"github.com/stretchr/testify/assert"

	"coppertone.tech/fraktal/mev-bot/pkg/cache"
)

// TestNewUniswapV2PoolDiscovery tests the constructor for pool discovery
func TestNewUniswapV2PoolDiscovery(t *testing.T) {
	tests := []struct {
		name      string
		client    interface{} // Using interface{} since we can't easily mock ethclient
		poolCache cache.PoolCache
		wantError bool
	}{
		{
			name:      "nil client should error",
			client:    nil,
			poolCache: cache.NewPoolCache(),
			wantError: true,
		},
		{
			name:      "nil cache should error",
			client:    "mock", // Not nil but not a real client
			poolCache: nil,
			wantError: true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			// We can't actually create a real client here without RPC endpoint
			// This test mainly validates the nil checks
			// Real integration tests would use actual Arbitrum RPC
			if tt.client == nil {
				_, err := NewUniswapV2PoolDiscovery(nil, tt.poolCache)
				if tt.wantError {
					assert.Error(t, err)
				} else {
					assert.NoError(t, err)
				}
			}
		})
	}
}

// TestMajorTokenPairs validates that the major token pairs are correctly defined
func TestMajorTokenPairs(t *testing.T) {
	// Verify we have the expected pairs
	assert.NotEmpty(t, MajorTokenPairs, "should have major token pairs defined")
	assert.GreaterOrEqual(t, len(MajorTokenPairs), 10, "should have at least 10 major pairs")

	// Verify WETH/USDC pair exists (most liquid pair)
	foundWETHUSDC := false
	for _, pair := range MajorTokenPairs {
		if (pair[0] == WETH && pair[1] == USDC) || (pair[0] == USDC && pair[1] == WETH) {
			foundWETHUSDC = true
			break
		}
	}
	assert.True(t, foundWETHUSDC, "should include WETH/USDC pair")
}

// TestGetTokenDecimals validates the token decimals helper
func TestGetTokenDecimals(t *testing.T) {
	tests := []struct {
		name     string
		token    common.Address
		expected uint8
	}{
		{
			name:     "WETH should be 18 decimals",
			token:    WETH,
			expected: 18,
		},
		{
			name:     "USDC should be 6 decimals",
			token:    USDC,
			expected: 6,
		},
		{
			name:     "USDT should be 6 decimals",
			token:    USDT,
			expected: 6,
		},
		{
			name:     "ARB should be 18 decimals",
			token:    ARB,
			expected: 18,
		},
		{
			name:     "WBTC should be 18 decimals (Arbitrum wrapped BTC)",
			token:    WBTC,
			expected: 18,
		},
		{
			name:     "unknown token should default to 18",
			token:    common.HexToAddress("0x0000000000000000000000000000000000000001"),
			expected: 18,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			decimals := getTokenDecimals(tt.token)
			assert.Equal(t, tt.expected, decimals)
		})
	}
}

// TestUniswapV2FactoryAddress validates the factory address is set
func TestUniswapV2FactoryAddress(t *testing.T) {
	// Verify factory address is not zero
	assert.NotEqual(t, common.Address{}, UniswapV2FactoryAddress, "factory address should not be zero")

	// Verify it matches the known Arbitrum UniswapV2 factory
	expectedFactory := common.HexToAddress("0xf1D7CC64Fb4452F05c498126312eBE29f30Fbcf9")
	assert.Equal(t, expectedFactory, UniswapV2FactoryAddress, "should match Arbitrum UniswapV2 factory")
}

// TestWellKnownTokenAddresses validates all token addresses are non-zero
func TestWellKnownTokenAddresses(t *testing.T) {
	tokens := map[string]common.Address{
		"WETH": WETH,
		"USDC": USDC,
		"USDT": USDT,
		"ARB":  ARB,
		"WBTC": WBTC,
		"DAI":  DAI,
		"LINK": LINK,
		"UNI":  UNI,
	}

	for name, addr := range tokens {
		t.Run(name, func(t *testing.T) {
			assert.NotEqual(t, common.Address{}, addr, "%s address should not be zero", name)
		})
	}
}

// NOTE: Integration tests that actually call Arbitrum RPC would go in a separate file
// marked with build tags (e.g., // +build integration) so they don't run in CI
// without proper RPC configuration. Example:
//
// // +build integration
//
// func TestDiscoverMajorPools_Integration(t *testing.T) {
//     // This would require ARBITRUM_RPC_URL environment variable
//     rpcURL := os.Getenv("ARBITRUM_RPC_URL")
//     if rpcURL == "" {
//         t.Skip("ARBITRUM_RPC_URL not set")
//     }
//
//     client, err := ethclient.Dial(rpcURL)
//     require.NoError(t, err)
//     defer client.Close()
//
//     poolCache := cache.NewPoolCache()
//     discovery, err := NewUniswapV2PoolDiscovery(client, poolCache)
//     require.NoError(t, err)
//
//     ctx := context.Background()
//     count, err := discovery.DiscoverMajorPools(ctx)
//     assert.NoError(t, err)
//     assert.Greater(t, count, 0, "should discover at least one pool")
// }