use rstest::*;
use std::env;
use trustformers::config_management::ConfigurationManager;
use trustformers::error::TrustformersError;
use trustformers::hub::get_cache_dir;

/// Cross-platform compatibility tests for TrustformeRS
/// These tests verify functionality across different platforms, architectures, and environments

#[cfg(test)]
mod compatibility_tests {
    use super::*;

    /// Test platform-specific path handling
    #[rstest]
    fn test_platform_path_compatibility() {
        let cache_dir = get_cache_dir().expect("Should get cache directory");

        // Test path separators work on current platform
        let model_path = cache_dir.join("models").join("test-model");
        assert!(model_path.is_absolute());

        // Test path component handling
        let components: Vec<_> = model_path.components().collect();
        assert!(!components.is_empty());

        // Test path string conversion
        let path_str = model_path.to_string_lossy();
        assert!(!path_str.is_empty());
    }

    /// Test memory alignment across architectures
    // TODO: Implement GlobalMemoryPool or remove this test
    #[rstest]
    #[ignore = "GlobalMemoryPool not implemented"]
    fn test_memory_alignment_compatibility() {
        // let pool = GlobalMemoryPool::instance();

        // Test different alignment requirements
        // for alignment in [8, 16, 32, 64, 128] {
        //     let size = 1024;
        //     let ptr =
        //         pool.allocate_aligned(size, alignment).expect("Should allocate aligned memory");

        //     // Verify alignment
        //     assert_eq!(
        //         ptr as usize % alignment,
        //         0,
        //         "Memory should be aligned to {} bytes",
        //         alignment
        //     );

        //     pool.deallocate(ptr, size);
        // }

        // Placeholder test to avoid empty function
        assert!(true);
    }

    /// Test endianness compatibility
    #[rstest]
    fn test_endianness_compatibility() {
        let test_value: u32 = 0x12345678;
        let bytes = test_value.to_le_bytes();
        let reconstructed = u32::from_le_bytes(bytes);
        assert_eq!(test_value, reconstructed);

        // Test f32 endianness
        let float_value: f32 = 3.14159;
        let float_bytes = float_value.to_le_bytes();
        let reconstructed_float = f32::from_le_bytes(float_bytes);
        assert!((float_value - reconstructed_float).abs() < f32::EPSILON);
    }

    /// Test CPU architecture specific features
    #[rstest]
    fn test_cpu_architecture_compatibility() {
        // Test CPU features detection
        #[cfg(target_arch = "x86_64")]
        {
            // Test x86_64 specific functionality
            let features = ["sse", "sse2", "avx"];
            for feature in features {
                // Test that we can query CPU features without crashing
                println!("Testing CPU feature: {}", feature);
            }
        }

        #[cfg(target_arch = "aarch64")]
        {
            // Test ARM64 specific functionality
            let features = ["neon"];
            for feature in features {
                println!("Testing ARM feature: {}", feature);
            }
        }

        // Test pointer size consistency
        assert_eq!(
            std::mem::size_of::<usize>(),
            std::mem::size_of::<*const u8>()
        );
    }

    /// Test thread safety across platforms
    // TODO: Implement GlobalMemoryPool or remove this test
    #[rstest]
    #[ignore = "GlobalMemoryPool not implemented"]
    fn test_thread_safety_compatibility() {
        // use std::sync::{Arc, Barrier};

        // let num_threads = 4;
        // let barrier = Arc::new(Barrier::new(num_threads));
        // let pool = Arc::new(GlobalMemoryPool::instance());

        // let handles: Vec<_> = (0..num_threads)
        //     .map(|i| {
        //         let barrier = barrier.clone();
        //         let pool = pool.clone();
        //         thread::spawn(move || {
        //             barrier.wait();

        //             // Test concurrent memory allocation
        //             let size = 1024 + i * 512;
        //             let ptr = pool.allocate(size).expect("Should allocate memory");

        //             // Do some work
        //             thread::sleep(Duration::from_millis(10));

        //             pool.deallocate(ptr, size);
        //         })
        //     })
        //     .collect();

        // for handle in handles {
        //     handle.join().expect("Thread should complete successfully");
        // }

        // Placeholder test to avoid empty function
        assert!(true);
    }

    /// Test file system compatibility
    #[rstest]
    fn test_filesystem_compatibility() {
        let temp_dir = std::env::temp_dir();
        let test_file = temp_dir.join("trustformers_test.tmp");

        // Test file creation and deletion
        std::fs::write(&test_file, b"test data").expect("Should write test file");
        assert!(test_file.exists());

        let content = std::fs::read(&test_file).expect("Should read test file");
        assert_eq!(content, b"test data");

        std::fs::remove_file(&test_file).expect("Should remove test file");
        assert!(!test_file.exists());
    }

    /// Test environment variable handling
    #[rstest]
    fn test_environment_variable_compatibility() {
        // Test setting and getting environment variables
        let test_var = "TRUSTFORMERS_TEST_VAR";
        let test_value = "test_value_123";

        env::set_var(test_var, test_value);
        assert_eq!(env::var(test_var).unwrap(), test_value);

        env::remove_var(test_var);
        assert!(env::var(test_var).is_err());
    }

    /// Test numeric precision across platforms
    #[rstest]
    fn test_numeric_precision_compatibility() {
        // Test f32 precision
        let a: f32 = 0.1;
        let b: f32 = 0.2;
        let c: f32 = 0.3;
        let sum = a + b;

        // Use appropriate epsilon for f32 comparison
        assert!((sum - c).abs() < 1e-6, "f32 precision should be consistent");

        // Test f64 precision
        let a64: f64 = 0.1;
        let b64: f64 = 0.2;
        let c64: f64 = 0.3;
        let sum64 = a64 + b64;

        assert!(
            (sum64 - c64).abs() < 1e-15,
            "f64 precision should be consistent"
        );
    }

    /// Test zero-copy operations compatibility
    // TODO: Implement ZeroCopyTensorView or remove this test
    #[rstest]
    #[ignore = "ZeroCopyTensorView not implemented"]
    fn test_zero_copy_compatibility() {
        // let data = vec![1.0f32, 2.0, 3.0, 4.0, 5.0, 6.0];
        // let shape = vec![2, 3];

        // // Test zero-copy tensor creation
        // let tensor_view =
        //     ZeroCopyTensorView::from_slice(&data, &shape).expect("Should create zero-copy view");

        // // Test that data is accessible
        // assert_eq!(tensor_view.shape(), &shape);
        // assert_eq!(tensor_view.data().len(), data.len());

        // // Test subview creation
        // let subview = tensor_view.subview(&[0..1, 0..2]).expect("Should create subview");
        // assert_eq!(subview.shape(), &[1, 2]);

        // Placeholder test to avoid empty function
        assert!(true);
    }

    /// Test platform-specific compilation features
    #[rstest]
    #[allow(unexpected_cfgs)]
    fn test_compilation_features_compatibility() {
        // Test that required features are available
        #[cfg(feature = "std")]
        {
            println!("std feature is available");
        }

        #[cfg(feature = "alloc")]
        {
            println!("alloc feature is available");
        }

        // Test optional features gracefully
        #[cfg(feature = "cuda")]
        {
            println!("CUDA feature is available");
        }
        #[cfg(not(feature = "cuda"))]
        {
            println!("CUDA feature is not available");
        }

        #[cfg(feature = "mkl")]
        {
            println!("MKL feature is available");
        }
        #[cfg(not(feature = "mkl"))]
        {
            println!("MKL feature is not available");
        }
    }

    /// Test configuration serialization compatibility
    #[rstest]
    fn test_config_serialization_compatibility() {
        let config = serde_json::json!({
            "model_type": "bert",
            "hidden_size": 768,
            "num_attention_heads": 12,
            "num_hidden_layers": 12,
            "intermediate_size": 3072,
            "hidden_act": "gelu",
            "hidden_dropout_prob": 0.1,
            "attention_probs_dropout_prob": 0.1,
            "max_position_embeddings": 512,
            "type_vocab_size": 2,
            "vocab_size": 30522
        });

        // Test JSON serialization/deserialization
        let json_str = serde_json::to_string(&config).expect("Should serialize to JSON");
        let deserialized: serde_json::Value =
            serde_json::from_str(&json_str).expect("Should deserialize from JSON");
        assert_eq!(config, deserialized);

        // Test pretty printing
        let pretty_json = serde_json::to_string_pretty(&config).expect("Should pretty print");
        assert!(pretty_json.len() > json_str.len());
    }

    /// Test SIMD compatibility where available
    #[rstest]
    fn test_simd_compatibility() {
        let data1 = vec![1.0f32, 2.0, 3.0, 4.0];
        let data2 = vec![5.0f32, 6.0, 7.0, 8.0];
        let mut result = vec![0.0f32; 4];

        // Test basic vector operations (fallback implementation)
        for i in 0..4 {
            result[i] = data1[i] + data2[i];
        }

        let expected = vec![6.0f32, 8.0, 10.0, 12.0];
        assert_eq!(result, expected);
    }

    /// Test async runtime compatibility
    #[tokio::test]
    async fn test_async_runtime_compatibility() {
        use tokio::time::{sleep, Duration};

        // Test basic async operations
        let start = std::time::Instant::now();
        sleep(Duration::from_millis(10)).await;
        let elapsed = start.elapsed();

        assert!(elapsed >= Duration::from_millis(9));
        assert!(elapsed < Duration::from_millis(100));

        // Test async task spawning
        let handle = tokio::spawn(async {
            sleep(Duration::from_millis(1)).await;
            42
        });

        let result = handle.await.expect("Task should complete");
        assert_eq!(result, 42);
    }

    /// Test error handling compatibility
    #[rstest]
    fn test_error_handling_compatibility() {
        // Test different error types
        let io_error = std::io::Error::new(std::io::ErrorKind::NotFound, "File not found");
        let trustformers_error = TrustformersError::Io {
            message: io_error.to_string(),
            path: None,
            suggestion: Some("Check file permissions and disk space".to_string()),
        };

        // Test error display
        let error_msg = format!("{}", trustformers_error);
        assert!(!error_msg.is_empty());

        // Test error debugging
        let debug_msg = format!("{:?}", trustformers_error);
        assert!(!debug_msg.is_empty());
    }

    /// Test profiler compatibility across platforms
    // TODO: Implement GlobalProfiler or remove this test
    #[rstest]
    #[ignore = "GlobalProfiler not implemented"]
    fn test_profiler_compatibility() {
        // let profiler = GlobalProfiler::instance();

        // Test basic profiling operations
        // let session_id = profiler.start_session("compatibility_test");
        // assert!(session_id.is_ok());

        // let session_id = session_id.unwrap();

        // // Test operation timing
        // profiler.start_operation(&session_id, "test_operation", None);
        // thread::sleep(Duration::from_millis(1));
        // profiler.end_operation(&session_id, "test_operation");

        // // Test session cleanup
        // let result = profiler.end_session(&session_id);
        // assert!(result.is_ok());

        // Placeholder test to avoid empty function
        assert!(true);
    }

    /// Test configuration validation across platforms
    #[rstest]
    fn test_config_validation_compatibility() {
        let config_manager = ConfigurationManager::new();

        // Test configuration with platform-specific paths
        let config = serde_json::json!({
            "cache_dir": get_cache_dir().unwrap(),
            "model_type": "bert",
            "hidden_size": 768
        });

        let validation_result = config_manager.validate_config("model", &config);
        // Should not panic on any platform
        println!("Validation result: {:?}", validation_result);
    }
}

/// Platform-specific tests
#[cfg(test)]
mod platform_specific_tests {
    use super::*;

    #[cfg(target_os = "windows")]
    mod windows_tests {
        use super::*;

        #[rstest]
        fn test_windows_path_handling() {
            let cache_dir = get_cache_dir().expect("Should get cache directory");
            let path_str = cache_dir.to_string_lossy();

            // Windows paths might contain backslashes
            if path_str.contains('\\') {
                println!("Windows-style path detected: {}", path_str);
            }

            // Test UNC path handling if applicable
            if path_str.starts_with(r"\\") {
                println!("UNC path detected: {}", path_str);
            }
        }
    }

    #[cfg(target_os = "linux")]
    mod linux_tests {
        use super::*;

        #[rstest]
        fn test_linux_path_handling() {
            let cache_dir = get_cache_dir().expect("Should get cache directory");
            let path_str = cache_dir.to_string_lossy();

            // Linux paths should use forward slashes
            assert!(
                path_str.contains('/'),
                "Linux paths should contain forward slashes"
            );
            assert!(path_str.starts_with('/'), "Linux paths should be absolute");
        }
    }

    #[cfg(target_os = "macos")]
    mod macos_tests {
        use super::*;

        #[rstest]
        fn test_macos_path_handling() {
            let cache_dir = get_cache_dir().expect("Should get cache directory");
            let path_str = cache_dir.to_string_lossy();

            // macOS paths should use forward slashes
            assert!(
                path_str.contains('/'),
                "macOS paths should contain forward slashes"
            );
            assert!(path_str.starts_with('/'), "macOS paths should be absolute");

            // Might be under /Users or /System
            assert!(
                path_str.starts_with("/Users")
                    || path_str.starts_with("/System")
                    || path_str.starts_with("/Library")
            );
        }
    }
}

/// Architecture-specific tests
#[cfg(test)]
mod architecture_tests {
    use super::*;

    #[cfg(target_arch = "x86_64")]
    mod x86_64_tests {
        use super::*;

        #[rstest]
        fn test_x86_64_features() {
            // Test that pointers are 64-bit
            assert_eq!(std::mem::size_of::<usize>(), 8);
            assert_eq!(std::mem::size_of::<*const u8>(), 8);

            // Test alignment requirements
            assert_eq!(std::mem::align_of::<f64>(), 8);
            assert_eq!(std::mem::align_of::<i64>(), 8);
        }
    }

    #[cfg(target_arch = "aarch64")]
    mod aarch64_tests {
        use super::*;

        #[rstest]
        fn test_aarch64_features() {
            // Test that pointers are 64-bit
            assert_eq!(std::mem::size_of::<usize>(), 8);
            assert_eq!(std::mem::size_of::<*const u8>(), 8);

            // Test ARM64-specific alignment
            assert_eq!(std::mem::align_of::<f64>(), 8);
            assert_eq!(std::mem::align_of::<i64>(), 8);
        }
    }

    #[cfg(target_arch = "x86")]
    mod x86_tests {
        use super::*;

        #[rstest]
        fn test_x86_features() {
            // Test that pointers are 32-bit
            assert_eq!(std::mem::size_of::<usize>(), 4);
            assert_eq!(std::mem::size_of::<*const u8>(), 4);
        }
    }
}
