use anyhow::Result;
use std::sync::Arc;
use crate::datastore::NodeStore;

pub struct ABTestRunner {
    backend_a: Arc<dyn NodeStore>,
    backend_b: Arc<dyn NodeStore>,
    metrics_collector: MetricsCollector,
}

impl ABTestRunner {
    pub async fn new(
        backend_a: Arc<dyn NodeStore>,
        backend_b: Arc<dyn NodeStore>,
    ) -> Result<Self> {
        Ok(Self {
            backend_a,
            backend_b,
            metrics_collector: MetricsCollector::new(),
        })
    }
    
    pub async fn run_parallel_test<F, T>(
        &self,
        test_name: &str,
        test_fn: F,
    ) -> Result<ABTestResult<T>>
    where
        F: Fn(Arc<dyn NodeStore>) -> Result<T> + Send + Sync,
        T: PartialEq + std::fmt::Debug,
    {
        let start_a = Instant::now();
        let result_a = test_fn(self.backend_a.clone())?;
        let duration_a = start_a.elapsed();
        
        let start_b = Instant::now();
        let result_b = test_fn(self.backend_b.clone())?;
        let duration_b = start_b.elapsed();
        
        // Validate results match
        assert_eq!(result_a, result_b, "Backend results diverged!");
        
        // Collect metrics
        self.metrics_collector.record(test_name, duration_a, duration_b);
        
        Ok(ABTestResult {
            backend_a_duration: duration_a,
            backend_b_duration: duration_b,
            delta_percent: calculate_delta(duration_a, duration_b),
            result: result_a,
        })
    }
}

#[derive(Debug)]
pub struct ABTestResult<T> {
    pub backend_a_duration: Duration,
    pub backend_b_duration: Duration,
    pub delta_percent: f64,
    pub result: T,
}

use std::time::Duration;

pub struct MetricsCollector {
    metrics: Vec<OperationMetric>,
}

#[derive(Debug, Clone)]
pub struct OperationMetric {
    pub operation: String,
    pub backend_a_duration: Duration,
    pub backend_b_duration: Duration,
    pub timestamp: SystemTime,
}

impl MetricsCollector {
    pub fn new() -> Self {
        Self { metrics: Vec::new() }
    }
    
    pub fn record(
        &mut self,
        operation: &str,
        backend_a_duration: Duration,
        backend_b_duration: Duration,
    ) {
        self.metrics.push(OperationMetric {
            operation: operation.to_string(),
            backend_a_duration,
            backend_b_duration,
            timestamp: SystemTime::now(),
        });
    }
    
    pub fn generate_report(&self) -> MetricsReport {
        // Calculate averages, percentiles, deltas
        MetricsReport::from_metrics(&self.metrics)
    }
    
    pub fn export_csv(&self, path: &Path) -> Result<()> {
        // Export metrics to CSV for analysis
    }
}

#[tokio::test]
async fn test_ab_crud_operations() {
    let turso = create_turso_store().await.unwrap();
    let surreal = create_surreal_store().await.unwrap();
    
    let runner = ABTestRunner::new(turso, surreal).await.unwrap();
    
    // Test create_node
    let result = runner.run_parallel_test("create_node", |store| {
        store.create_node(test_node()).await
    }).await.unwrap();
    
    assert!(result.delta_percent < 100.0, "Performance delta >100%");
    
    // Test query_nodes
    let result = runner.run_parallel_test("query_nodes", |store| {
        store.query_nodes(test_filter()).await
    }).await.unwrap();
    
    assert!(result.delta_percent < 100.0, "Performance delta >100%");
    
    // Generate report
    let report = runner.metrics_collector.generate_report();
    println!("{:?}", report);
}

#[tokio::test]
async fn test_ab_scale_100k() {
    // Run 100K node test on both backends
    // Validate performance within 2x of each other
}

#[tokio::test]
async fn test_ab_pagination() {
    // Test deep pagination on both backends
    // Validate results identical and performance acceptable
}

#[tokio::test]
async fn test_ab_complex_queries() {
    // Test complex queries on both backends
    // Validate query results match exactly
}