package fuse_test

import (
	"os"
	"path/filepath"
	"testing"
	"time"
)

// ============================================================================
// IMPORTANT: This file contains a STANDALONE demonstration of the FUSE testing
// framework that works around Go module conflicts between the main framework
// and the SeaweedFS parent module.
//
// PURPOSE:
// - Provides a working demonstration of framework capabilities for CI/CD
// - Simulates FUSE operations using local filesystem (not actual FUSE mounts)
// - Validates the testing approach and framework design
// - Enables CI integration while module conflicts are resolved
//
// DUPLICATION RATIONALE:
// - The full framework (framework.go) has Go module conflicts with parent project
// - This standalone version proves the concept works without those conflicts
// - Once module issues are resolved, this can be removed or simplified
//
// TODO: Remove this file once framework.go module conflicts are resolved
// ============================================================================

// DemoTestConfig represents test configuration for the standalone demo
// Note: This duplicates TestConfig from framework.go due to module conflicts
type DemoTestConfig struct {
	ChunkSizeMB int
	Replication string
	TestTimeout time.Duration
}

// DefaultDemoTestConfig returns default test configuration for demo
func DefaultDemoTestConfig() DemoTestConfig {
	return DemoTestConfig{
		ChunkSizeMB: 8,
		Replication: "000",
		TestTimeout: 30 * time.Minute,
	}
}

// DemoFuseTestFramework represents the standalone testing framework
// Note: This simulates FUSE operations using local filesystem for demonstration
type DemoFuseTestFramework struct {
	t         *testing.T
	config    DemoTestConfig
	mountPath string
	cleanup   []func()
}

// NewDemoFuseTestFramework creates a new demo test framework instance
func NewDemoFuseTestFramework(t *testing.T, config DemoTestConfig) *DemoFuseTestFramework {
	return &DemoFuseTestFramework{
		t:       t,
		config:  config,
		cleanup: make([]func(), 0),
	}
}

// CreateTestFile creates a test file with given content
func (f *DemoFuseTestFramework) CreateTestFile(filename string, content []byte) {
	if f.mountPath == "" {
		f.mountPath = "/tmp/fuse_test_mount"
	}

	fullPath := filepath.Join(f.mountPath, filename)

	// Ensure directory exists
	os.MkdirAll(filepath.Dir(fullPath), 0755)

	// Write file (simulated - in real implementation would use FUSE mount)
	err := os.WriteFile(fullPath, content, 0644)
	if err != nil {
		f.t.Fatalf("Failed to create test file %s: %v", filename, err)
	}
}

// AssertFileExists checks if file exists
func (f *DemoFuseTestFramework) AssertFileExists(filename string) {
	fullPath := filepath.Join(f.mountPath, filename)
	if _, err := os.Stat(fullPath); os.IsNotExist(err) {
		f.t.Fatalf("Expected file %s to exist, but it doesn't", filename)
	}
}

// AssertFileContent checks file content matches expected
func (f *DemoFuseTestFramework) AssertFileContent(filename string, expected []byte) {
	fullPath := filepath.Join(f.mountPath, filename)
	actual, err := os.ReadFile(fullPath)
	if err != nil {
		f.t.Fatalf("Failed to read file %s: %v", filename, err)
	}

	if string(actual) != string(expected) {
		f.t.Fatalf("File content mismatch for %s.\nExpected: %q\nActual: %q",
			filename, string(expected), string(actual))
	}
}

// Cleanup performs test cleanup
func (f *DemoFuseTestFramework) Cleanup() {
	for i := len(f.cleanup) - 1; i >= 0; i-- {
		f.cleanup[i]()
	}

	// Clean up test mount directory
	if f.mountPath != "" {
		os.RemoveAll(f.mountPath)
	}
}

// TestFrameworkDemo demonstrates the FUSE testing framework capabilities
// NOTE: This is a STANDALONE DEMONSTRATION that simulates FUSE operations
// using local filesystem instead of actual FUSE mounts. It exists to prove
// the framework concept works while Go module conflicts are resolved.
func TestFrameworkDemo(t *testing.T) {
	t.Log("SeaweedFS FUSE Integration Testing Framework Demo")
	t.Log("This demo simulates FUSE operations using local filesystem")

	// Initialize demo framework
	framework := NewDemoFuseTestFramework(t, DefaultDemoTestConfig())
	defer framework.Cleanup()

	t.Run("ConfigurationValidation", func(t *testing.T) {
		config := DefaultDemoTestConfig()
		if config.ChunkSizeMB != 8 {
			t.Errorf("Expected chunk size 8MB, got %d", config.ChunkSizeMB)
		}
		if config.Replication != "000" {
			t.Errorf("Expected replication '000', got %s", config.Replication)
		}
		t.Log("Configuration validation passed")
	})

	t.Run("BasicFileOperations", func(t *testing.T) {
		// Test file creation and reading
		content := []byte("Hello, SeaweedFS FUSE Testing!")
		filename := "demo_test.txt"

		t.Log("Creating test file...")
		framework.CreateTestFile(filename, content)

		t.Log("Verifying file exists...")
		framework.AssertFileExists(filename)

		t.Log("Verifying file content...")
		framework.AssertFileContent(filename, content)

		t.Log("Basic file operations test passed")
	})

	t.Run("LargeFileSimulation", func(t *testing.T) {
		// Simulate large file testing
		largeContent := make([]byte, 1024*1024) // 1MB
		for i := range largeContent {
			largeContent[i] = byte(i % 256)
		}

		filename := "large_file_demo.dat"

		t.Log("Creating large test file (1MB)...")
		framework.CreateTestFile(filename, largeContent)

		t.Log("Verifying large file...")
		framework.AssertFileExists(filename)
		framework.AssertFileContent(filename, largeContent)

		t.Log("Large file operations test passed")
	})

	t.Run("ConcurrencySimulation", func(t *testing.T) {
		// Simulate concurrent operations
		numFiles := 5

		t.Logf("Creating %d files concurrently...", numFiles)

		for i := 0; i < numFiles; i++ {
			filename := filepath.Join("concurrent", "file_"+string(rune('A'+i))+".txt")
			content := []byte("Concurrent file content " + string(rune('A'+i)))

			framework.CreateTestFile(filename, content)
			framework.AssertFileExists(filename)
		}

		t.Log("Concurrent operations simulation passed")
	})

	t.Log("Framework demonstration completed successfully!")
	t.Log("This DEMO shows the planned FUSE testing capabilities:")
	t.Log("   • Automated cluster setup/teardown (simulated)")
	t.Log("   • File operations testing (local filesystem simulation)")
	t.Log("   • Directory operations testing (planned)")
	t.Log("   • Large file handling (demonstrated)")
	t.Log("   • Concurrent operations testing (simulated)")
	t.Log("   • Error scenario validation (planned)")
	t.Log("   • Performance validation (planned)")
	t.Log("Full framework available in framework.go (pending module resolution)")
}
