package compressutil

import (
	"bytes"
	"compress/gzip"
	"testing"
)

func TestCompressUtil_CompressDecompress(t *testing.T) {
	t.Parallel()

	tests := []struct {
		compressionType   string
		compressionConfig CompressionConfig
		canary            byte
	}{
		{
			"GZIP default implicit",
			CompressionConfig{Type: CompressionTypeGzip},
			CompressionCanaryGzip,
		},
		{
			"GZIP default explicit",
			CompressionConfig{Type: CompressionTypeGzip, GzipCompressionLevel: gzip.DefaultCompression},
			CompressionCanaryGzip,
		},
		{
			"GZIP best speed",
			CompressionConfig{Type: CompressionTypeGzip, GzipCompressionLevel: gzip.BestSpeed},
			CompressionCanaryGzip,
		},
		{
			"GZIP best compression",
			CompressionConfig{Type: CompressionTypeGzip, GzipCompressionLevel: gzip.BestCompression},
			CompressionCanaryGzip,
		},
		{
			"Snappy",
			CompressionConfig{Type: CompressionTypeSnappy},
			CompressionCanarySnappy,
		},
		{
			"LZ4",
			CompressionConfig{Type: CompressionTypeLZ4},
			CompressionCanaryLZ4,
		},
		{
			"LZW",
			CompressionConfig{Type: CompressionTypeLZW},
			CompressionCanaryLZW,
		},
	}

	inputJSONBytes := []byte(`{"sample":"data","verification":"process"}`)

	for _, test := range tests {
		// Compress the input
		compressedJSONBytes, err := Compress(inputJSONBytes, &test.compressionConfig)
		if err != nil {
			t.Fatalf("compress error (%s): %s", test.compressionType, err)
		}
		if len(compressedJSONBytes) == 0 {
			t.Fatalf("failed to compress data in %s format", test.compressionType)
		}

		// Check the presence of the canary
		if compressedJSONBytes[0] != test.canary {
			t.Fatalf("bad (%s): compression canary: expected: %d actual: %d", test.compressionType, test.canary, compressedJSONBytes[0])
		}

		decompressedJSONBytes, wasNotCompressed, err := Decompress(compressedJSONBytes)
		if err != nil {
			t.Fatalf("decompress error (%s): %s", test.compressionType, err)
		}

		// Check if the input for decompress was not compressed in the first place
		if wasNotCompressed {
			t.Fatalf("bad (%s): expected compressed bytes", test.compressionType)
		}

		if len(decompressedJSONBytes) == 0 {
			t.Fatalf("bad (%s): expected decompressed bytes", test.compressionType)
		}

		// Compare the value after decompression
		if !bytes.Equal(inputJSONBytes, decompressedJSONBytes) {
			t.Fatalf("bad (%s): decompressed value;\nexpected: %q\nactual: %q", test.compressionType, string(inputJSONBytes), string(decompressedJSONBytes))
		}
	}
}

func TestCompressUtil_InvalidConfigurations(t *testing.T) {
	t.Parallel()

	inputJSONBytes := []byte(`{"sample":"data","verification":"process"}`)

	// Test nil configuration
	if _, err := Compress(inputJSONBytes, nil); err == nil {
		t.Fatal("expected an error")
	}

	// Test invalid configuration
	if _, err := Compress(inputJSONBytes, &CompressionConfig{}); err == nil {
		t.Fatal("expected an error")
	}
}