package uniswap

import (
	"math/big"
	"testing"
)

// TestPricePrecisionRoundTrip verifies precision of price conversions
func TestPricePrecisionRoundTrip(t *testing.T) {
	testCases := []struct {
		name         string
		sqrtPriceX96 string
		expectedTick int
	}{
		{
			name:         "Price 1.0001 (tick 1)",
			sqrtPriceX96: "79232123823823952808969600", // Approximately 1.0001^0.5 * 2^96
			expectedTick: 1,
		},
		{
			name:         "Price 1.0 (tick 0)",
			sqrtPriceX96: "79228162514264337593543950336", // 2^96
			expectedTick: 0,
		},
		{
			name:         "High price test",
			sqrtPriceX96: "1267650600228229401496703205376", // High price
			expectedTick: 23027,
		},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			// Parse input
			sqrtPriceX96, ok := new(big.Int).SetString(tc.sqrtPriceX96, 10)
			if !ok {
				t.Fatalf("Failed to parse sqrtPriceX96: %s", tc.sqrtPriceX96)
			}

			// Convert to tick
			calculatedTick := SqrtPriceX96ToTick(sqrtPriceX96)

			// Convert back to sqrtPriceX96
			roundTripSqrtPrice := TickToSqrtPriceX96(calculatedTick)

			// Calculate precision loss
			originalFloat := new(big.Float).SetInt(sqrtPriceX96)
			roundTripFloat := new(big.Float).SetInt(roundTripSqrtPrice)

			// Calculate percentage difference
			diff := new(big.Float).Sub(originalFloat, roundTripFloat)
			diff.Quo(diff, originalFloat)
			diff.Abs(diff)

			precisionLoss, _ := diff.Float64()

			t.Logf("Original sqrtPriceX96: %s", sqrtPriceX96.String())
			t.Logf("Calculated tick: %d", calculatedTick)
			t.Logf("Round-trip sqrtPriceX96: %s", roundTripSqrtPrice.String())
			t.Logf("Precision loss: %.10f%%", precisionLoss*100)

			// Verify tick is within reasonable range
			if calculatedTick < -887272 || calculatedTick > 887272 {
				t.Errorf("Tick %d is outside valid range [-887272, 887272]", calculatedTick)
			}

			// Verify precision loss is acceptable (less than 0.01%)
			if precisionLoss > 0.0001 {
				t.Errorf("Precision loss %.10f%% exceeds threshold 0.01%%", precisionLoss*100)
			}
		})
	}
}

// TestPriceConversionAccuracy tests specific known price conversions
func TestPriceConversionAccuracy(t *testing.T) {
	testCases := []struct {
		name          string
		sqrtPriceX96  string
		expectedPrice float64
		tolerance     float64
	}{
		{
			name:          "Price 1.0",
			sqrtPriceX96:  "79228162514264337593543950336", // 2^96
			expectedPrice: 1.0,
			tolerance:     0.000001,
		},
		{
			name:          "Price 4.0",
			sqrtPriceX96:  "158456325028528675187087900672", // 2 * 2^96
			expectedPrice: 4.0,
			tolerance:     0.000001,
		},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			sqrtPriceX96, ok := new(big.Int).SetString(tc.sqrtPriceX96, 10)
			if !ok {
				t.Fatalf("Failed to parse sqrtPriceX96: %s", tc.sqrtPriceX96)
			}

			price := SqrtPriceX96ToPrice(sqrtPriceX96)
			priceFloat, _ := price.Float64()

			diff := priceFloat - tc.expectedPrice
			if diff < 0 {
				diff = -diff
			}

			t.Logf("Calculated price: %.10f", priceFloat)
			t.Logf("Expected price: %.10f", tc.expectedPrice)
			t.Logf("Difference: %.10f", diff)

			if diff > tc.tolerance {
				t.Errorf("Price difference %.10f exceeds tolerance %.10f", diff, tc.tolerance)
			}
		})
	}
}

// TestTickBoundaries verifies tick calculations at boundaries
func TestTickBoundaries(t *testing.T) {
	testCases := []struct {
		name string
		tick int
	}{
		{"Minimum tick", -887272},
		{"Maximum tick", 887272},
		{"Zero tick", 0},
		{"Positive tick", 100000},
		{"Negative tick", -100000},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			// Convert tick to sqrtPriceX96
			sqrtPriceX96 := TickToSqrtPriceX96(tc.tick)

			// Convert back to tick
			roundTripTick := SqrtPriceX96ToTick(sqrtPriceX96)

			// Calculate tick difference
			tickDiff := tc.tick - roundTripTick
			if tickDiff < 0 {
				tickDiff = -tickDiff
			}

			t.Logf("Original tick: %d", tc.tick)
			t.Logf("Round-trip tick: %d", roundTripTick)
			t.Logf("Tick difference: %d", tickDiff)

			// Verify tick difference is within acceptable range
			if tickDiff > 1 {
				t.Errorf("Tick difference %d exceeds threshold 1", tickDiff)
			}
		})
	}
}

// BenchmarkSqrtPriceConversion benchmarks price conversion performance
func BenchmarkSqrtPriceConversion(b *testing.B) {
	sqrtPriceX96, _ := new(big.Int).SetString("79228162514264337593543950336", 10)

	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		SqrtPriceX96ToPrice(sqrtPriceX96)
	}
}

// BenchmarkTickConversion benchmarks tick conversion performance
func BenchmarkTickConversion(b *testing.B) {
	tick := 100000

	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		TickToSqrtPriceX96(tick)
	}
}