// steamcache/steamcache_test.go
package steamcache

import (
	"io"
	"net/http"
	"os"
	"path/filepath"
	"testing"
)

func TestCaching(t *testing.T) {
	td := t.TempDir()

	os.WriteFile(filepath.Join(td, "key2"), []byte("value2"), 0644)

	sc := New("localhost:8080", "1G", "1G", td, "", "lru", "lru")

	w, err := sc.vfs.Create("key", 5)
	if err != nil {
		t.Errorf("Create failed: %v", err)
	}
	w.Write([]byte("value"))
	w.Close()

	w, err = sc.vfs.Create("key1", 6)
	if err != nil {
		t.Errorf("Create failed: %v", err)
	}
	w.Write([]byte("value1"))
	w.Close()

	if sc.diskgc.Size() != 17 {
		t.Errorf("Size failed: got %d, want %d", sc.diskgc.Size(), 17)
	}

	if sc.vfs.Size() != 17 {
		t.Errorf("Size failed: got %d, want %d", sc.vfs.Size(), 17)
	}

	rc, err := sc.vfs.Open("key")
	if err != nil {
		t.Errorf("Open failed: %v", err)
	}
	d, _ := io.ReadAll(rc)
	rc.Close()
	if string(d) != "value" {
		t.Errorf("Get failed: got %s, want %s", d, "value")
	}

	rc, err = sc.vfs.Open("key1")
	if err != nil {
		t.Errorf("Open failed: %v", err)
	}
	d, _ = io.ReadAll(rc)
	rc.Close()
	if string(d) != "value1" {
		t.Errorf("Get failed: got %s, want %s", d, "value1")
	}

	rc, err = sc.vfs.Open("key2")
	if err != nil {
		t.Errorf("Open failed: %v", err)
	}
	d, _ = io.ReadAll(rc)
	rc.Close()
	if string(d) != "value2" {
		t.Errorf("Get failed: got %s, want %s", d, "value2")
	}

	if sc.diskgc.Size() != 17 {
		t.Errorf("Size failed: got %d, want %d", sc.diskgc.Size(), 17)
	}

	if sc.vfs.Size() != 17 {
		t.Errorf("Size failed: got %d, want %d", sc.vfs.Size(), 17)
	}

	sc.memory.Delete("key2")
	os.Remove(filepath.Join(td, "key2"))

	if _, err := sc.vfs.Open("key2"); err == nil {
		t.Errorf("Open failed: got nil, want error")
	}
}

func TestCacheMissAndHit(t *testing.T) {
	sc := New("localhost:8080", "0", "1G", t.TempDir(), "", "lru", "lru")

	key := "testkey"
	value := []byte("testvalue")

	// Simulate miss: but since no upstream, skip full ServeHTTP, test VFS
	w, err := sc.vfs.Create(key, int64(len(value)))
	if err != nil {
		t.Fatal(err)
	}
	w.Write(value)
	w.Close()

	rc, err := sc.vfs.Open(key)
	if err != nil {
		t.Fatal(err)
	}
	got, _ := io.ReadAll(rc)
	rc.Close()

	if string(got) != string(value) {
		t.Errorf("expected %s, got %s", value, got)
	}
}

func TestHashExtraction(t *testing.T) {
	// Test the specific key from the user's issue
	testCases := []struct {
		filename       string
		expectedHash   string
		shouldHaveHash bool
	}{
		{
			filename:       "e89c81a1a926eb4732e146bc806491da8a7d89ca",
			expectedHash:   "e89c81a1a926eb4732e146bc806491da8a7d89ca",
			shouldHaveHash: true, // Now it should work with the new standalone hash pattern
		},
		{
			filename:       "chunk_e89c81a1a926eb4732e146bc806491da8a7d89ca",
			expectedHash:   "",
			shouldHaveHash: false, // No longer supported with simplified patterns
		},
		{
			filename:       "file.e89c81a1a926eb4732e146bc806491da8a7d89ca.chunk",
			expectedHash:   "",
			shouldHaveHash: false, // No longer supported with simplified patterns
		},
		{
			filename:       "chunk_abc123def456",
			expectedHash:   "",
			shouldHaveHash: false, // Not 40 chars
		},
	}

	for _, tc := range testCases {
		hash, hasHash := extractHashFromFilename(tc.filename)
		if hasHash != tc.shouldHaveHash {
			t.Errorf("filename: %s, expected hasHash: %v, got: %v", tc.filename, tc.shouldHaveHash, hasHash)
		}
		if hasHash && hash != tc.expectedHash {
			t.Errorf("filename: %s, expected hash: %s, got: %s", tc.filename, tc.expectedHash, hash)
		}
	}
}

func TestHashCalculation(t *testing.T) {
	// Test data
	testData := []byte("Hello, World!")

	// Calculate hash
	hash := calculateFileHash(testData)

	// Expected SHA1 hash of "Hello, World!"
	expectedHash := "0a0a9f2a6772942557ab5355d76af442f8f65e01"

	if hash != expectedHash {
		t.Errorf("Hash calculation failed: expected %s, got %s", expectedHash, hash)
	}

	// Test verification
	if !verifyFileHash(testData, expectedHash) {
		t.Error("Hash verification failed for correct hash")
	}

	if verifyFileHash(testData, "wronghash") {
		t.Error("Hash verification passed for wrong hash")
	}
}

func TestHashVerificationWithRealData(t *testing.T) {
	// Test with some real data to ensure our hash calculation is correct
	testCases := []struct {
		data     string
		expected string
	}{
		{"", "da39a3ee5e6b4b0d3255bfef95601890afd80709"},              // SHA1 of empty string
		{"test", "a94a8fe5ccb19ba61c4c0873d391e987982fbbd3"},          // SHA1 of "test"
		{"Hello, World!", "0a0a9f2a6772942557ab5355d76af442f8f65e01"}, // SHA1 of "Hello, World!"
	}

	for _, tc := range testCases {
		data := []byte(tc.data)
		hash := calculateFileHash(data)
		if hash != tc.expected {
			t.Errorf("Hash calculation failed for '%s': expected %s, got %s", tc.data, tc.expected, hash)
		}

		if !verifyFileHash(data, tc.expected) {
			t.Errorf("Hash verification failed for '%s'", tc.data)
		}
	}
}

func TestResponseHashCalculation(t *testing.T) {
	// Create a mock HTTP response
	resp := &http.Response{
		StatusCode: 200,
		Status:     "200 OK",
		Header: http.Header{
			"Content-Type":   []string{"application/octet-stream"},
			"Content-Length": []string{"13"},
			"Cache-Control":  []string{"public, max-age=3600"},
		},
	}

	bodyData := []byte("Hello, World!")
	
	// Calculate response hash
	responseHash := calculateResponseHash(resp, bodyData)
	
	// The hash should be different from just the body hash
	bodyHash := calculateFileHash(bodyData)
	
	if responseHash == bodyHash {
		t.Error("Response hash should be different from body hash when headers are present")
	}
	
	// Test that the same response produces the same hash
	responseHash2 := calculateResponseHash(resp, bodyData)
	if responseHash != responseHash2 {
		t.Error("Response hash should be consistent for the same response")
	}
	
	// Test with different headers
	resp2 := &http.Response{
		StatusCode: 200,
		Status:     "200 OK",
		Header: http.Header{
			"Content-Type":   []string{"text/plain"},
			"Content-Length": []string{"13"},
		},
	}
	
	responseHash3 := calculateResponseHash(resp2, bodyData)
	if responseHash == responseHash3 {
		t.Error("Response hash should be different for different headers")
	}
}