// Copyright (c) 2026 Charles KWON OhJun (charleskwonohjun@gmail.com)
// All rights reserved.

package dbf

import (
	"bytes"
	"testing"
)

// TestEncodeNumericKey_SortOrder pins the sortable-numeric encoding
// used by NTX/CDX indexes. Lexicographic byte order of the encoded
// keys must match numeric order across signs and magnitudes — the
// previous `%20.10f` encoding sorted -100 AFTER 99 because '-'
// (0x2D) > ' ' (0x20).
func TestEncodeNumericKey_SortOrder(t *testing.T) {
	// Strictly ascending input values.
	values := []float64{-1e9, -1e6, -1000, -100, -99, -1, -0.5, 0, 0.5, 1, 99, 100, 1000, 1e6, 1e9}
	encoded := make([][]byte, len(values))
	for i, v := range values {
		encoded[i] = encodeNumericKey(v)
	}
	for i := 1; i < len(encoded); i++ {
		if bytes.Compare(encoded[i-1], encoded[i]) >= 0 {
			t.Errorf("encoding[%v]=%q !< encoding[%v]=%q",
				values[i-1], encoded[i-1], values[i], encoded[i])
		}
	}
}

// TestEncodeNumericKey_NegativeBeforePositive guards the specific
// inversion called out in the bug report: -100 must encode to a key
// that sorts before 99.
func TestEncodeNumericKey_NegativeBeforePositive(t *testing.T) {
	neg100 := encodeNumericKey(-100)
	pos99 := encodeNumericKey(99)
	if bytes.Compare(neg100, pos99) >= 0 {
		t.Errorf("expected -100 < 99 lexicographically; got %q !< %q", neg100, pos99)
	}
}

// TestEncodeNumericKey_NegativeMagnitudeOrder ensures that within
// the negative range, more-negative values sort earlier.
func TestEncodeNumericKey_NegativeMagnitudeOrder(t *testing.T) {
	neg200 := encodeNumericKey(-200)
	neg100 := encodeNumericKey(-100)
	neg1 := encodeNumericKey(-1)
	if bytes.Compare(neg200, neg100) >= 0 {
		t.Errorf("-200 should sort before -100: %q vs %q", neg200, neg100)
	}
	if bytes.Compare(neg100, neg1) >= 0 {
		t.Errorf("-100 should sort before -1: %q vs %q", neg100, neg1)
	}
}