package imgcache

import (
	"fmt"
	"math"
	"testing"
)

func TestSizePercentSafeWithZeroFetchBytes(t *testing.T) {
	// Simulate the calculation from processAndStore
	fetchBytes := int64(0)
	outputSize := int64(100)

	var sizePercent float64
	if fetchBytes > 0 {
		sizePercent = float64(outputSize) / float64(fetchBytes) * 100.0
	}

	// sizePercent should be 0, not Inf or NaN
	if math.IsInf(sizePercent, 0) || math.IsNaN(sizePercent) {
		t.Errorf("sizePercent = %f, should not be Inf/NaN", sizePercent)
	}

	// Should produce valid log output
	result := fmt.Sprintf("%.1f%%", sizePercent)
	if result != "0.0%" {
		t.Errorf("formatted size ratio = %q, want %q", result, "0.0%")
	}
}

func TestSizePercentNormalCase(t *testing.T) {
	fetchBytes := int64(1000)
	outputSize := int64(500)

	var sizePercent float64
	if fetchBytes > 0 {
		sizePercent = float64(outputSize) / float64(fetchBytes) * 100.0
	}

	if math.Abs(sizePercent-50.0) > 0.001 {
		t.Errorf("sizePercent = %f, want 50.0", sizePercent)
	}
}