//! WGPU Multi-GPU Tests - Popperian Falsification Claims 26-50
//!
//! EXTREME TDD: These tests are written FIRST, before implementation.
//! All tests should FAIL initially until implementation is complete.
//!
//! Run: cargo test --features "gpu-wgpu,monitor" --test `wgpu_multi_gpu_test`
//! Run with GPU: cargo test --features "gpu-wgpu,monitor" --test `wgpu_multi_gpu_test` -- --ignored
//!
//! NOTE: These tests require real GPU hardware and may block on Metal initialization.
//! They are marked #[ignore] by default and should be run manually on systems with GPUs.

#![cfg(feature = "gpu-wgpu")]
#![allow(unused_macros, unused_imports, unused_variables, unused_mut, dead_code)]

/// Helper macro to mark tests as requiring real GPU
macro_rules! gpu_test {
    ($name:ident, $body:block) => {
        #[test]
        #[ignore = "Requires real GPU - run with --ignored"]
        fn $name() $body
    };
}

use std::time::{Duration, Instant};

// These imports will fail until we implement the modules
#[cfg(feature = "gpu-wgpu")]
use trueno_viz::monitor::ffi::wgpu::{GpuAdapterInfo, WgpuBackendType, WgpuMonitor};

// ============================================================================
// CLAIMS 26-35: GPU Detection & Enumeration
// ============================================================================

/// Claim 26: WGPU detects all physical GPUs
/// Failure criterion: Missing GPU compared to `system_profiler`
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_26_wgpu_detects_all_gpus() {
    let monitor = WgpuMonitor::new();
    let adapters = monitor.adapters();

    // Must detect at least one GPU on any modern system
    assert!(!adapters.is_empty(), "FALSIFIED Claim 26: No GPUs detected by WGPU");

    println!("Detected {} GPU adapter(s):", adapters.len());
    for adapter in adapters {
        println!("  - {} ({:?})", adapter.name, adapter.backend);
    }
}

/// Claim 27: Dual AMD W5700X both enumerated (Mac Pro specific)
/// Failure criterion: Count != 2 on Mac Pro with dual GPUs
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(all(feature = "gpu-wgpu", target_os = "macos"))]
fn claim_27_dual_amd_w5700x_enumerated() {
    let monitor = WgpuMonitor::new();

    if monitor.has_dual_amd() {
        let amd_count =
            monitor.adapters().iter().filter(|a| a.name.contains("AMD") && a.is_discrete()).count();

        assert_eq!(amd_count, 2, "FALSIFIED Claim 27: Expected 2 AMD GPUs, found {}", amd_count);
    } else {
        println!("Skipping Claim 27: No dual AMD configuration detected");
    }
}

/// Claim 28: GPU names match system report
/// Failure criterion: Name mismatch with `system_profiler`
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_28_gpu_names_accurate() {
    let monitor = WgpuMonitor::new();

    for adapter in monitor.adapters() {
        // Name should not be empty or generic
        assert!(!adapter.name.is_empty(), "FALSIFIED Claim 28: GPU name is empty");
        assert!(!adapter.name.contains("Unknown"), "FALSIFIED Claim 28: GPU name is 'Unknown'");

        println!("GPU name: {}", adapter.name);
    }
}

/// Claim 29: Backend correctly identified as Metal on macOS
/// Failure criterion: Wrong backend on macOS
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(all(feature = "gpu-wgpu", target_os = "macos"))]
fn claim_29_metal_backend_on_macos() {
    let monitor = WgpuMonitor::new();

    // On macOS, primary backend should be Metal
    if let Some(primary) = monitor.primary_adapter() {
        assert!(
            matches!(primary.backend, WgpuBackendType::Metal),
            "FALSIFIED Claim 29: Expected Metal backend on macOS, got {:?}",
            primary.backend
        );
    }
}

/// Claim 30: Backend correctly identified as Vulkan on Linux
/// Failure criterion: Wrong backend on Linux
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(all(feature = "gpu-wgpu", target_os = "linux"))]
fn claim_30_vulkan_backend_on_linux() {
    let monitor = WgpuMonitor::new();

    if let Some(primary) = monitor.primary_adapter() {
        assert!(
            matches!(primary.backend, WgpuBackendType::Vulkan),
            "FALSIFIED Claim 30: Expected Vulkan backend on Linux, got {:?}",
            primary.backend
        );
    }
}

/// Claim 31: Device type is `DiscreteGpu` for dedicated cards
/// Failure criterion: Wrong device type for discrete GPU
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_31_discrete_gpu_type() {
    let monitor = WgpuMonitor::new();

    for adapter in monitor.adapters() {
        if adapter.name.contains("Radeon")
            || adapter.name.contains("GeForce")
            || adapter.name.contains("RTX")
        {
            assert!(
                adapter.is_discrete(),
                "FALSIFIED Claim 31: {} should be DiscreteGpu",
                adapter.name
            );
        }
    }
}

/// Claim 32: WGPU initialization < 100ms
/// Failure criterion: Init > 100ms
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_32_wgpu_init_under_100ms() {
    let start = Instant::now();
    let _monitor = WgpuMonitor::new();
    let elapsed = start.elapsed();

    assert!(
        elapsed < Duration::from_millis(100),
        "FALSIFIED Claim 32: WGPU init took {elapsed:?}, expected < 100ms"
    );
}

/// Claim 33: Adapter enumeration < 50ms
/// Failure criterion: Enum > 50ms
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_33_adapter_enum_under_50ms() {
    let monitor = WgpuMonitor::new();

    let start = Instant::now();
    let _adapters = monitor.adapters();
    let elapsed = start.elapsed();

    assert!(
        elapsed < Duration::from_millis(50),
        "FALSIFIED Claim 33: Adapter enumeration took {elapsed:?}, expected < 50ms"
    );
}

/// Claim 34: No blocking in WGPU discovery
/// Failure criterion: Main thread blocked (tested via timeout)
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_34_non_blocking_discovery() {
    // If this test doesn't complete in 500ms, it's blocking
    let start = Instant::now();

    let monitor = WgpuMonitor::new();
    let _ = monitor.adapters();
    let _ = monitor.discrete_gpu_count();

    let elapsed = start.elapsed();
    assert!(
        elapsed < Duration::from_millis(500),
        "FALSIFIED Claim 34: Discovery appears to block ({elapsed:?})"
    );
}

/// Claim 35: WGPU works without GPU (software fallback)
/// Failure criterion: Crash without GPU
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_35_graceful_without_gpu() {
    // This should not panic even if no GPU is available
    let monitor = WgpuMonitor::new();

    // These should all return valid (possibly empty) results
    let adapters = monitor.adapters();
    let count = monitor.discrete_gpu_count();
    let primary = monitor.primary_adapter();

    // At minimum, should not crash
    println!(
        "Adapters: {}, Discrete: {}, Primary: {:?}",
        adapters.len(),
        count,
        primary.map(|a| a.name.clone())
    );
}

// ============================================================================
// CLAIMS 36-45: Metrics & Tracking
// ============================================================================

/// Claim 36: Queue submission count increments correctly
/// Failure criterion: Count mismatch
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_36_queue_submission_tracking() {
    let mut monitor = WgpuMonitor::new();

    let initial = monitor.queue_submissions(0);

    // Simulate some submissions (in real impl, this would track actual submissions)
    monitor.record_submission(0);
    monitor.record_submission(0);
    monitor.record_submission(0);

    let final_count = monitor.queue_submissions(0);

    assert_eq!(
        final_count,
        initial + 3,
        "FALSIFIED Claim 36: Expected {} submissions, got {}",
        initial + 3,
        final_count
    );
}

/// Claim 37: Buffer allocation tracking accurate to 1KB
/// Failure criterion: Tracking error > 1KB
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_37_buffer_allocation_tracking() {
    let mut monitor = WgpuMonitor::new();

    let test_size = 1024 * 1024; // 1MB
    monitor.record_buffer_allocation(0, test_size);

    let tracked = monitor.buffer_allocated_bytes(0);

    let error = (tracked as i64 - test_size as i64).unsigned_abs();
    assert!(error <= 1024, "FALSIFIED Claim 37: Buffer tracking error {error} > 1KB");
}

/// Claim 38: Compute dispatch counting accurate
/// Failure criterion: Count mismatch
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_38_compute_dispatch_counting() {
    let mut monitor = WgpuMonitor::new();

    let initial = monitor.compute_dispatches(0);

    monitor.record_dispatch(0);
    monitor.record_dispatch(0);

    let final_count = monitor.compute_dispatches(0);

    assert_eq!(final_count, initial + 2, "FALSIFIED Claim 38: Dispatch count mismatch");
}

/// Claim 39: Per-GPU workload isolation
/// Failure criterion: Cross-GPU interference
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_39_per_gpu_isolation() {
    let mut monitor = WgpuMonitor::new();

    // Record to GPU 0 only
    monitor.record_dispatch(0);
    monitor.record_dispatch(0);
    monitor.record_dispatch(0);

    // GPU 1 should be unaffected
    let gpu1_dispatches = monitor.compute_dispatches(1);

    assert_eq!(gpu1_dispatches, 0, "FALSIFIED Claim 39: GPU 1 affected by GPU 0 operations");
}

/// Claim 40: WGPU collector is 100% safe Rust
/// Failure criterion: Unsafe code found
/// This is a compile-time check - the module should have #![`forbid(unsafe_code)`]
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_40_wgpu_is_safe_rust() {
    // This test verifies at compile time that the wgpu module forbids unsafe
    // If it compiles, the module is safe
    let _ = WgpuMonitor::new();

    // The actual verification is in the module's #![forbid(unsafe_code)] attribute
    // This test just ensures the module compiles and is usable
}

/// Claim 41: WGPU feature is optional
/// Failure criterion: Compile error without feature
/// This is tested by CI building without the feature
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
fn claim_41_wgpu_feature_optional() {
    // This test always passes - the actual test is that
    // `cargo build` works without `gpu-wgpu` feature
    #[cfg(feature = "gpu-wgpu")]
    {
        let _ = WgpuMonitor::new();
    }

    #[cfg(not(feature = "gpu-wgpu"))]
    {
        // Without the feature, WgpuMonitor shouldn't exist
        // This branch should compile fine
    }
}

/// Claim 42: Graceful fallback without WGPU feature
/// Failure criterion: Panic without feature
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_42_graceful_fallback() {
    // Create monitor and verify it doesn't panic
    let monitor = WgpuMonitor::new();

    // All operations should be safe even if WGPU fails to initialize
    let _ = monitor.adapters();
    let _ = monitor.discrete_gpu_count();
    let _ = monitor.primary_adapter();
}

/// Claim 43: WGPU errors don't crash the application
/// Failure criterion: Crash on error
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_43_error_handling() {
    let monitor = WgpuMonitor::new();

    // Request invalid GPU index - should not crash
    let result = monitor.adapter_info(999);
    assert!(result.is_none(), "FALSIFIED Claim 43: Invalid index should return None");

    // Request metrics for non-existent GPU - should not crash
    let dispatches = monitor.compute_dispatches(999);
    assert_eq!(dispatches, 0, "Invalid GPU should return 0 dispatches");
}

/// Claim 44: GPU memory limits respected
/// Failure criterion: OOM crash
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_44_memory_limits() {
    let monitor = WgpuMonitor::new();

    // Should be able to query limits without crashing
    if let Some(adapter) = monitor.primary_adapter() {
        let limits = monitor.adapter_limits(0);
        assert!(limits.max_buffer_size > 0, "FALSIFIED Claim 44: Invalid memory limits");
        println!("Max buffer size: {} bytes", limits.max_buffer_size);
    }
}

/// Claim 45: WGPU instance is reusable
/// Failure criterion: Resource leak
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_45_instance_reusable() {
    let mut monitor = WgpuMonitor::new();

    // Collect multiple times - should not leak
    for i in 0..100 {
        let adapters = monitor.adapters();
        let _ = monitor.collect_metrics();

        if i == 0 {
            println!("First collection: {} adapters", adapters.len());
        }
    }

    // If we get here without OOM, we pass
}

// ============================================================================
// CLAIMS 46-50: Advanced Features
// ============================================================================

/// Claim 46: Adapter info is cacheable
/// Failure criterion: Stale data served after GPU change
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_46_adapter_caching() {
    let monitor = WgpuMonitor::new();

    // First call
    let adapters1 = monitor.adapters();

    // Second call should return same data (cached)
    let adapters2 = monitor.adapters();

    assert_eq!(
        adapters1.len(),
        adapters2.len(),
        "FALSIFIED Claim 46: Adapter count changed between calls"
    );
}

/// Claim 47: WGPU works in async context
/// Failure criterion: Blocking detected
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_47_async_compatible() {
    // Verify the monitor can be used in async code
    // The actual async test would use tokio/async-std

    let monitor = WgpuMonitor::new();

    // Monitor should be Send + Sync for async usage
    fn assert_send_sync<T: Send + Sync>() {}
    assert_send_sync::<WgpuMonitor>();

    let _ = monitor.adapters();
}

/// Claim 48: Multi-GPU load balancing works
/// Failure criterion: Imbalanced load
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_48_load_balancing() {
    let mut monitor = WgpuMonitor::new();

    if monitor.discrete_gpu_count() >= 2 {
        // Simulate round-robin dispatch
        for i in 0..10 {
            let gpu = monitor.next_gpu_round_robin();
            monitor.record_dispatch(gpu);
        }

        // Check balance (should be roughly even)
        let gpu0_load = monitor.compute_dispatches(0);
        let gpu1_load = monitor.compute_dispatches(1);

        let diff = (gpu0_load as i64 - gpu1_load as i64).unsigned_abs();
        assert!(
            diff <= 2,
            "FALSIFIED Claim 48: Imbalanced load: GPU0={gpu0_load}, GPU1={gpu1_load}"
        );
    }
}

/// Claim 49: GPU hotplug handled gracefully
/// Failure criterion: Crash on GPU removal
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_49_hotplug_handling() {
    let mut monitor = WgpuMonitor::new();

    // Simulate GPU removal by invalidating adapter
    monitor.invalidate_adapter(0);

    // Should not crash when accessing invalidated adapter
    let info = monitor.adapter_info(0);
    // May be None or return stale data, but should NOT crash

    // Refresh should recover
    monitor.refresh_adapters();
    let _ = monitor.adapters();
}

/// Claim 50: WGPU metrics update at 10Hz minimum
/// Failure criterion: Update rate < 10Hz
#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn claim_50_update_rate() {
    let mut monitor = WgpuMonitor::new();

    let start = Instant::now();
    let mut updates = 0;

    // Try to update for 200ms
    while start.elapsed() < Duration::from_millis(200) {
        let _ = monitor.collect_metrics();
        updates += 1;
    }

    // At 10Hz minimum, we should get at least 2 updates in 200ms
    assert!(updates >= 2, "FALSIFIED Claim 50: Only {updates} updates in 200ms (need 10Hz)");

    let hz = f64::from(updates) / 0.2;
    println!("Update rate: {hz:.1} Hz");
}

// ============================================================================
// Helper test for coverage
// ============================================================================

#[test]
#[ignore = "Requires real GPU - run with --ignored"]
#[cfg(feature = "gpu-wgpu")]
fn test_wgpu_monitor_full_api() {
    let mut monitor = WgpuMonitor::new();

    // Exercise full API for coverage
    let _ = monitor.adapters();
    let _ = monitor.discrete_gpu_count();
    let _ = monitor.primary_adapter();
    let _ = monitor.adapter_info(0);
    let _ = monitor.adapter_limits(0);
    let _ = monitor.has_dual_amd();

    monitor.record_submission(0);
    monitor.record_dispatch(0);
    monitor.record_buffer_allocation(0, 1024);

    let _ = monitor.queue_submissions(0);
    let _ = monitor.compute_dispatches(0);
    let _ = monitor.buffer_allocated_bytes(0);

    let _ = monitor.next_gpu_round_robin();
    monitor.invalidate_adapter(0);
    monitor.refresh_adapters();

    let _ = monitor.collect_metrics();
}
