package ws

import (
	"bytes"
	"testing"
)

func TestCompressDecompressRoundTrip(t *testing.T) {
	c := NewCompressor(6)

	original := []byte(`{"type":"chat_message","payload":{"conversation_id":"conv1","message":"hello world"}}`)

	compressed, err := c.Compress(original)
	if err != nil {
		t.Fatalf("Compress failed: %v", err)
	}

	if len(compressed) >= len(original) {
		t.Logf("warning: compressed size (%d) >= original size (%d), but this can happen for small payloads", len(compressed), len(original))
	}

	if !IsCompressed(compressed) {
		t.Fatal("IsCompressed should return true for gzip data")
	}

	decompressed, err := c.Decompress(compressed)
	if err != nil {
		t.Fatalf("Decompress failed: %v", err)
	}

	if !bytes.Equal(decompressed, original) {
		t.Fatalf("round-trip mismatch: got %q, want %q", decompressed, original)
	}
}

func TestIsCompressed(t *testing.T) {
	if IsCompressed([]byte{}) {
		t.Fatal("empty data should not be considered compressed")
	}
	if IsCompressed([]byte{0x00}) {
		t.Fatal("0x00 should not be considered gzip magic byte")
	}
	if !IsCompressed([]byte{0x1F, 0x8B}) {
		t.Fatal("gzip magic bytes should be detected")
	}
}

func TestDecompressNonGzipData(t *testing.T) {
	c := NewCompressor(6)
	_, err := c.Decompress([]byte("not gzip data"))
	if err == nil {
		t.Fatal("expected error when decompressing non-gzip data")
	}
}

func TestDefaultCompressor(t *testing.T) {
	data := []byte("test data for default compressor")
	compressed, err := DefaultCompressor.Compress(data)
	if err != nil {
		t.Fatalf("DefaultCompressor.Compress failed: %v", err)
	}
	decompressed, err := DefaultCompressor.Decompress(compressed)
	if err != nil {
		t.Fatalf("DefaultCompressor.Decompress failed: %v", err)
	}
	if !bytes.Equal(decompressed, data) {
		t.Fatalf("DefaultCompressor round-trip mismatch")
	}
}

func BenchmarkCompress(b *testing.B) {
	c := NewCompressor(6)
	data := bytes.Repeat([]byte(`{"type":"chat_message","payload":{"message":"hello"}}`), 10)
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		_, err := c.Compress(data)
		if err != nil {
			b.Fatal(err)
		}
	}
}

func BenchmarkDecompress(b *testing.B) {
	c := NewCompressor(6)
	data := bytes.Repeat([]byte(`{"type":"chat_message","payload":{"message":"hello"}}`), 10)
	compressed, _ := c.Compress(data)
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		_, err := c.Decompress(compressed)
		if err != nil {
			b.Fatal(err)
		}
	}
}