import Foundation
import DriverKit
import BlockStorageDeviceDriverKit

class VDiskTestDriver: IOBlockStorageDevice {
    
    // Test DriverKit access to vdisk
    // Device: /dev/disk14 (vdisk)
    // Purpose: Verify if Block Storage Device Entitlement is required
    
    private var vdiskDevice: IOBlockStorageDevice?
    private var blockSize: UInt64 = 4096
    private var diskSize: UInt64 = 10527662080
    private var devicePath: String = "/dev/disk14"
    
    override init() {
        super.init()
        print("VDiskTestDriver initializing...")
        print("  Device Path: \(devicePath)")
        print("  Block Size: \(blockSize) Bytes")
        print("  Disk Size: \(diskSize) Bytes")
    }
    
    override func Start() -> IOReturn {
        print("VDiskTestDriver Start() called")
        
        let result = super.Start()
        
        if result == kIOReturnSuccess {
            print("VDiskTestDriver started successfully")
            
            // Initialize vdisk device
            initializeVDiskDevice()
            
            // Test Block Storage operations
            testBlockStorageOperations()
            
            // Report test results
            reportTestResults()
        } else {
            print("VDiskTestDriver start failed: \(result)")
            print("  Error: This may indicate Entitlement requirement")
        }
        
        return result
    }
    
    func initializeVDiskDevice() {
        print("Step 1: Initializing vdisk device...")
        
        print("  - Matching IOBlockStorageDevice...")
        
        // IOServiceMatching for Block Storage Device
        let matching = IOServiceMatching("IOBlockStorageDevice")
        
        if matching != nil {
            print("  - IOBlockStorageDevice matching successful")
            print("  - This indicates Block Storage Device DriverKit API is available")
        } else {
            print("  - IOBlockStorageDevice matching failed")
            print("  - This may indicate Entitlement is required")
        }
        
        print("  - vdisk device path: \(devicePath)")
        print("  - vdisk is a virtual Block Storage Device")
        print("  - vdisk can be accessed via /dev/disk14")
    }
    
    func testBlockStorageOperations() {
        print("Step 2: Testing Block Storage operations...")
        
        // Test read operations
        testReadOperations()
        
        // Test write operations
        testWriteOperations()
        
        // Test performance
        testPerformance()
    }
    
    func testReadOperations() {
        print("Test 1: Read Operations")
        
        print("  - Testing Block Storage read API...")
        print("  - Read from vdisk device")
        print("  - Read offset: 0")
        print("  - Read length: 4096 (one block)")
        
        // Placeholder: Actual read operation
        // In real implementation:
        // let readResult = readBlock(offset: 0, length: 4096)
        // print("    Read result: \(readResult.success ? "SUCCESS" : "FAILED")")
        
        print("    Read test: PLACEHOLDER (need actual DriverKit implementation)")
        print("    Note: Actual read requires DriverKit Extension Bundle to be loaded")
    }
    
    func testWriteOperations() {
        print("Test 2: Write Operations")
        
        print("  - Testing Block Storage write API...")
        print("  - Write to vdisk device")
        print("  - Write offset: 0")
        print("  - Write length: 4096 (one block)")
        
        // Placeholder: Actual write operation
        // In real implementation:
        // let writeResult = writeBlock(offset: 0, data: testData)
        // print("    Write result: \(writeResult.success ? "SUCCESS" : "FAILED")")
        
        print("    Write test: PLACEHOLDER (need actual DriverKit implementation)")
        print("    Note: Actual write requires DriverKit Extension Bundle to be loaded")
    }
    
    func testPerformance() {
        print("Test 3: Performance Test")
        
        print("  - Testing Block Storage performance...")
        print("  - Target read speed: >100 MB/s")
        print("  - Target write speed: >100 MB/s")
        print("  - Target IOPS: >1000")
        
        // Placeholder: Actual performance test
        print("    Performance test: PLACEHOLDER (need actual DriverKit implementation)")
        print("    Note: Actual performance requires DriverKit Extension Bundle to be loaded")
    }
    
    func reportTestResults() {
        print("Step 3: Reporting test results...")
        
        print("  Test Summary:")
        print("  - VDiskTestDriver initialization: SUCCESS")
        print("  - IOBlockStorageDevice API availability: TO BE VERIFIED")
        print("  - Block Storage operations: TO BE VERIFIED")
        
        print("  Key Findings:")
        print("  1. VDiskTestDriver created successfully")
        print("  2. IOBlockStorageDevice API imported successfully")
        print("  3. BlockStorageDeviceDriverKit.framework imported successfully")
        
        print("  Next Steps:")
        print("  1. Create DriverKit Extension Bundle")
        print("  2. Load DriverKit Extension")
        print("  3. Test actual Block Storage operations")
        print("  4. Verify if Entitlement is required")
    }
    
    override func Stop() -> IOReturn {
        print("VDiskTestDriver stopping...")
        
        // Cleanup
        vdiskDevice = nil
        
        return super.Stop()
    }
    
    deinit {
        print("VDiskTestDriver deinitialized")
    }
}

// Helper functions for testing
extension VDiskTestDriver {
    
    func readBlock(offset: UInt64, length: UInt64) -> ReadResult {
        // Placeholder: Actual read implementation
        return ReadResult(success: true, data: nil)
    }
    
    func writeBlock(offset: UInt64, data: Data) -> WriteResult {
        // Placeholder: Actual write implementation
        return WriteResult(success: true)
    }
}

// Result structures
struct ReadResult {
    let success: Bool
    let data: Data?
}

struct WriteResult {
    let success: Bool
}