#![cfg_attr(coverage_nightly, coverage(off))]
use super::*;

// GPU resource scheduler
/// Gpu scheduler.
pub struct GpuScheduler {
    _limits: GpuLimits,
}

impl GpuScheduler {
    #[provable_contracts_macros::contract("pmat-core.yaml", equation = "check_compliance")]
    /// Create a new instance.
    pub fn new(limits: GpuLimits) -> Result<Self, ResourceError> {
        Ok(Self { _limits: limits })
    }
}

impl ResourceController for GpuScheduler {
    fn apply_limits(&self, _limits: &ResourceLimits) -> Result<(), ResourceError> {
        Ok(())
    }

    fn get_usage(&self) -> Result<ResourceUsage, ResourceError> {
        Ok(ResourceUsage {
            cpu_percent: 0.0,
            memory_bytes: 0,
            gpu_memory_bytes: Some(0),
            gpu_compute_percent: Some(0.0),
            network_ingress_bytes: 0,
            network_egress_bytes: 0,
            disk_read_bytes: 0,
            disk_write_bytes: 0,
            timestamp: std::time::SystemTime::now(),
        })
    }

    fn release(&self) -> Result<(), ResourceError> {
        Ok(())
    }
}

#[cfg_attr(coverage_nightly, coverage(off))]
#[cfg(test)]
mod coverage_tests {
    use super::*;

    fn create_test_gpu_limits() -> GpuLimits {
        GpuLimits {
            device_id: 0,
            memory_bytes: 8 * 1024 * 1024 * 1024, // 8GB
            compute_percent: 100.0,
            exclusive: false,
        }
    }

    fn create_test_resource_limits() -> ResourceLimits {
        ResourceLimits::default()
    }

    #[test]
    fn test_gpu_scheduler_new_success() {
        let limits = create_test_gpu_limits();
        let result = GpuScheduler::new(limits);
        assert!(result.is_ok());
    }

    #[test]
    fn test_gpu_scheduler_new_with_different_device() {
        let limits = GpuLimits {
            device_id: 1,
            memory_bytes: 4 * 1024 * 1024 * 1024, // 4GB
            compute_percent: 50.0,
            exclusive: true,
        };
        let result = GpuScheduler::new(limits);
        assert!(result.is_ok());
    }

    #[test]
    fn test_gpu_scheduler_new_exclusive_mode() {
        let limits = GpuLimits {
            device_id: 0,
            memory_bytes: 16 * 1024 * 1024 * 1024, // 16GB
            compute_percent: 100.0,
            exclusive: true,
        };
        let result = GpuScheduler::new(limits);
        assert!(result.is_ok());
    }

    #[test]
    fn test_gpu_scheduler_new_with_minimal_resources() {
        let limits = GpuLimits {
            device_id: 0,
            memory_bytes: 1,
            compute_percent: 0.1,
            exclusive: false,
        };
        let result = GpuScheduler::new(limits);
        assert!(result.is_ok());
    }

    #[test]
    fn test_gpu_scheduler_apply_limits() {
        let limits = create_test_gpu_limits();
        let scheduler = GpuScheduler::new(limits).unwrap();
        let resource_limits = create_test_resource_limits();

        let result = scheduler.apply_limits(&resource_limits);
        assert!(result.is_ok());
    }

    #[test]
    fn test_gpu_scheduler_get_usage() {
        let limits = create_test_gpu_limits();
        let scheduler = GpuScheduler::new(limits).unwrap();

        let result = scheduler.get_usage();
        assert!(result.is_ok());

        let usage = result.unwrap();
        assert_eq!(usage.cpu_percent, 0.0);
        assert_eq!(usage.memory_bytes, 0);
        assert_eq!(usage.gpu_memory_bytes, Some(0));
        assert_eq!(usage.gpu_compute_percent, Some(0.0));
        assert_eq!(usage.network_ingress_bytes, 0);
        assert_eq!(usage.network_egress_bytes, 0);
        assert_eq!(usage.disk_read_bytes, 0);
        assert_eq!(usage.disk_write_bytes, 0);
    }

    #[test]
    fn test_gpu_scheduler_get_usage_reports_gpu_metrics() {
        let limits = create_test_gpu_limits();
        let scheduler = GpuScheduler::new(limits).unwrap();

        let usage = scheduler.get_usage().unwrap();

        // GPU scheduler should report GPU metrics (Some values)
        assert!(usage.gpu_memory_bytes.is_some());
        assert!(usage.gpu_compute_percent.is_some());
    }

    #[test]
    fn test_gpu_scheduler_get_usage_has_valid_timestamp() {
        let limits = create_test_gpu_limits();
        let scheduler = GpuScheduler::new(limits).unwrap();

        let before = std::time::SystemTime::now();
        let usage = scheduler.get_usage().unwrap();
        let after = std::time::SystemTime::now();

        assert!(usage.timestamp >= before);
        assert!(usage.timestamp <= after);
    }

    #[test]
    fn test_gpu_scheduler_release() {
        let limits = create_test_gpu_limits();
        let scheduler = GpuScheduler::new(limits).unwrap();

        let result = scheduler.release();
        assert!(result.is_ok());
    }

    #[test]
    fn test_gpu_scheduler_multiple_usage_calls() {
        let limits = create_test_gpu_limits();
        let scheduler = GpuScheduler::new(limits).unwrap();

        // Should be able to call get_usage multiple times
        for _ in 0..10 {
            assert!(scheduler.get_usage().is_ok());
        }
    }

    #[test]
    fn test_gpu_scheduler_apply_limits_with_gpu_config() {
        let limits = create_test_gpu_limits();
        let scheduler = GpuScheduler::new(limits).unwrap();

        // Create resource limits with GPU configuration
        let mut resource_limits = create_test_resource_limits();
        resource_limits.gpu = Some(GpuLimits {
            device_id: 0,
            memory_bytes: 4 * 1024 * 1024 * 1024,
            compute_percent: 50.0,
            exclusive: false,
        });

        let result = scheduler.apply_limits(&resource_limits);
        assert!(result.is_ok());
    }

    #[test]
    fn test_gpu_scheduler_release_then_get_usage() {
        let limits = create_test_gpu_limits();
        let scheduler = GpuScheduler::new(limits).unwrap();

        // Release first, then get usage (should still work)
        assert!(scheduler.release().is_ok());
        assert!(scheduler.get_usage().is_ok());
    }

    #[test]
    fn test_gpu_scheduler_with_zero_compute_percent() {
        let limits = GpuLimits {
            device_id: 0,
            memory_bytes: 1024,
            compute_percent: 0.0,
            exclusive: false,
        };
        let result = GpuScheduler::new(limits);
        assert!(result.is_ok());
    }
}
