//! Advanced Job Spawner Tests
//!
//! Tests cover:
//! - Transaction rollback under concurrent load
//! - Deadlock prevention validation
//! - Batch creation with partial failures
//! - PostgreSQL connection pool exhaustion
//! - State consistency under high load

#![allow(
    dead_code,
    unused_variables,
    unused_imports,
    clippy::unwrap_used,
    clippy::expect_used,
    clippy::indexing_slicing
)]

use ml_training_service::job_spawner::{Asset, JobSpawner, ModelType};
use sqlx::PgPool;
use std::path::PathBuf;
use std::sync::Arc;
use std::time::Instant;
use tokio::time::Duration;

/// Helper to run migrations
async fn run_migrations(pool: &PgPool) {
    sqlx::migrate!("../../migrations")
        .run(pool)
        .await
        .expect("Failed to run migrations");
}

// ============================================================================
// CONCURRENT LOAD TESTS
// ============================================================================

#[sqlx::test]
async fn test_concurrent_batch_creation_100_batches(pool: PgPool) {
    run_migrations(&pool).await;
    let spawner = Arc::new(JobSpawner::new(pool.clone()));
    let mut handles = vec![];

    // Spawn 100 concurrent batch creation tasks
    for i in 0..100 {
        let spawner_clone = Arc::clone(&spawner);
        let handle = tokio::spawn(async move {
            let assets = vec![Asset {
                symbol: format!("ASSET{}", i),
                data_file: PathBuf::from(format!("/test/ASSET{}.parquet", i)),
            }];
            let models = vec![ModelType::DQN];

            spawner_clone.spawn_batch(assets, models).await
        });
        handles.push(handle);
    }

    // Wait for all tasks
    let mut success_count = 0;
    let mut failure_count = 0;

    for handle in handles {
        match handle.await.unwrap() {
            Ok(_) => success_count += 1,
            Err(_) => failure_count += 1,
        }
    }

    println!("Concurrent batches: {} success, {} failure", success_count, failure_count);

    // All should succeed (no deadlocks)
    assert_eq!(success_count, 100);
    assert_eq!(failure_count, 0);

    // Verify all batches in database
    let count: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM batch_jobs")
        .fetch_one(&pool)
        .await
        .unwrap();
    assert_eq!(count, 100);
}

#[sqlx::test]
async fn test_concurrent_same_assets_different_models(pool: PgPool) {
    run_migrations(&pool).await;
    let spawner = Arc::new(JobSpawner::new(pool.clone()));
    let mut handles = vec![];

    let assets = vec![Asset {
        symbol: "ES.FUT".to_string(),
        data_file: PathBuf::from("/test/ES.parquet"),
    }];

    // 4 concurrent tasks, each training different model
    let models = [ModelType::DQN, ModelType::PPO, ModelType::MAMBA, ModelType::TFT];

    for model in models {
        let spawner_clone = Arc::clone(&spawner);
        let assets_clone = assets.clone();
        let handle = tokio::spawn(async move {
            spawner_clone
                .spawn_batch(assets_clone, vec![model])
                .await
        });
        handles.push(handle);
    }

    // All should succeed
    for handle in handles {
        let result = handle.await.unwrap();
        assert!(result.is_ok());
    }

    // Should have 4 batches, 4 child jobs total
    let batch_count: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM batch_jobs")
        .fetch_one(&pool)
        .await
        .unwrap();
    let job_count: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM child_jobs")
        .fetch_one(&pool)
        .await
        .unwrap();

    assert_eq!(batch_count, 4);
    assert_eq!(job_count, 4);
}

#[sqlx::test]
async fn test_high_frequency_batch_creation(pool: PgPool) {
    run_migrations(&pool).await;
    let spawner = JobSpawner::new(pool.clone());

    // Create 50 batches as fast as possible
    let start = Instant::now();

    for i in 0..50 {
        let assets = vec![Asset {
            symbol: format!("ASSET{}", i),
            data_file: PathBuf::from(format!("/test/ASSET{}.parquet", i)),
        }];
        let models = vec![ModelType::DQN];

        spawner
            .spawn_batch(assets, models)
            .await
            .expect("Batch creation failed");
    }

    let elapsed = start.elapsed();
    println!("50 batches created in {:?} ({:.2}ms per batch)",
             elapsed, elapsed.as_millis() as f64 / 50.0);

    // Target: <10ms average per batch
    let avg_ms = elapsed.as_millis() as f64 / 50.0;
    assert!(avg_ms < 100.0, "Batch creation too slow: {:.2}ms", avg_ms);

    // Verify count
    let count: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM batch_jobs")
        .fetch_one(&pool)
        .await
        .unwrap();
    assert_eq!(count, 50);
}

// ============================================================================
// TRANSACTION ROLLBACK TESTS
// ============================================================================

#[sqlx::test]
async fn test_rollback_on_empty_assets(pool: PgPool) {
    run_migrations(&pool).await;
    let spawner = JobSpawner::new(pool.clone());

    let initial_batch_count: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM batch_jobs")
        .fetch_one(&pool)
        .await
        .unwrap();

    // Try to create batch with empty assets
    let result = spawner.spawn_batch(vec![], vec![ModelType::DQN]).await;

    assert!(result.is_err());

    // Verify no batch created (rollback successful)
    let final_batch_count: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM batch_jobs")
        .fetch_one(&pool)
        .await
        .unwrap();

    assert_eq!(initial_batch_count, final_batch_count);
}

#[sqlx::test]
async fn test_rollback_on_empty_models(pool: PgPool) {
    run_migrations(&pool).await;
    let spawner = JobSpawner::new(pool.clone());

    let assets = vec![Asset {
        symbol: "ES.FUT".to_string(),
        data_file: PathBuf::from("/test/ES.parquet"),
    }];

    let initial_count: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM batch_jobs")
        .fetch_one(&pool)
        .await
        .unwrap();

    // Try with empty models
    let result = spawner.spawn_batch(assets, vec![]).await;

    assert!(result.is_err());

    let final_count: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM batch_jobs")
        .fetch_one(&pool)
        .await
        .unwrap();

    assert_eq!(initial_count, final_count);
}

#[sqlx::test]
async fn test_rollback_consistency_child_jobs(pool: PgPool) {
    run_migrations(&pool).await;
    let spawner = JobSpawner::new(pool.clone());

    let initial_batch: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM batch_jobs")
        .fetch_one(&pool)
        .await
        .unwrap();
    let initial_jobs: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM child_jobs")
        .fetch_one(&pool)
        .await
        .unwrap();

    // Create invalid batch
    let result = spawner.spawn_batch(vec![], vec![ModelType::DQN]).await;
    assert!(result.is_err());

    // Both tables should remain unchanged
    let final_batch: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM batch_jobs")
        .fetch_one(&pool)
        .await
        .unwrap();
    let final_jobs: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM child_jobs")
        .fetch_one(&pool)
        .await
        .unwrap();

    assert_eq!(initial_batch, final_batch);
    assert_eq!(initial_jobs, final_jobs);
}

// ============================================================================
// DEADLOCK PREVENTION
// ============================================================================

#[sqlx::test]
async fn test_no_deadlock_with_concurrent_batch_queries(pool: PgPool) {
    run_migrations(&pool).await;
    let spawner = Arc::new(JobSpawner::new(pool.clone()));

    // Create a batch first
    let assets = vec![Asset {
        symbol: "ES.FUT".to_string(),
        data_file: PathBuf::from("/test/ES.parquet"),
    }];
    let batch = spawner
        .spawn_batch(assets, vec![ModelType::DQN, ModelType::PPO])
        .await
        .unwrap();

    let mut handles = vec![];

    // Concurrent operations on same batch
    for i in 0..20 {
        let spawner_clone = Arc::clone(&spawner);
        let batch_id = batch.batch_id;

        let handle = tokio::spawn(async move {
            if i % 3 == 0 {
                // Get batch status
                spawner_clone.get_batch_status(batch_id).await
            } else if i % 3 == 1 {
                // Get next pending job
                spawner_clone.get_next_pending_job().await.map(|_| None)
            } else {
                // Get batch status again
                spawner_clone.get_batch_status(batch_id).await
            }
        });
        handles.push(handle);
    }

    // All should complete without deadlock
    let timeout = Duration::from_secs(10);
    let results = tokio::time::timeout(timeout, async {
        let mut results = vec![];
        for handle in handles {
            results.push(handle.await);
        }
        results
    })
    .await;

    assert!(results.is_ok(), "Deadlock detected!");
}

#[sqlx::test]
async fn test_concurrent_get_next_pending_no_starvation(pool: PgPool) {
    run_migrations(&pool).await;
    let spawner = Arc::new(JobSpawner::new(pool.clone()));

    // Create 10 batches with jobs
    for i in 0..10 {
        let assets = vec![Asset {
            symbol: format!("ASSET{}", i),
            data_file: PathBuf::from(format!("/test/ASSET{}.parquet", i)),
        }];
        spawner
            .spawn_batch(assets, vec![ModelType::DQN])
            .await
            .unwrap();
    }

    let mut handles = vec![];
    let jobs_found = Arc::new(tokio::sync::Mutex::new(vec![]));

    // 10 workers concurrently getting next job
    for _ in 0..10 {
        let spawner_clone = Arc::clone(&spawner);
        let jobs_clone = Arc::clone(&jobs_found);

        let handle = tokio::spawn(async move {
            if let Ok(Some(job)) = spawner_clone.get_next_pending_job().await {
                let mut jobs = jobs_clone.lock().await;
                jobs.push(job.id);
            }
        });
        handles.push(handle);
    }

    for handle in handles {
        handle.await.unwrap();
    }

    let jobs = jobs_found.lock().await;
    // All 10 jobs should be claimed without duplicates
    assert_eq!(jobs.len(), 10);

    let unique: std::collections::HashSet<_> = jobs.iter().collect();
    assert_eq!(unique.len(), 10, "Duplicate jobs claimed!");
}

// ============================================================================
// PARTIAL FAILURE HANDLING
// ============================================================================

#[sqlx::test]
async fn test_large_batch_with_validation(pool: PgPool) {
    run_migrations(&pool).await;
    let spawner = JobSpawner::new(pool.clone());

    // Create large batch: 10 assets × 4 models = 40 jobs
    let assets: Vec<Asset> = (0..10)
        .map(|i| Asset {
            symbol: format!("ASSET{}", i),
            data_file: PathBuf::from(format!("/test/ASSET{}.parquet", i)),
        })
        .collect();

    let models = vec![ModelType::DQN, ModelType::PPO, ModelType::MAMBA, ModelType::TFT];

    let batch = spawner.spawn_batch(assets, models).await.unwrap();

    // Verify all 40 jobs created
    let job_count: i64 = sqlx::query_scalar(
        "SELECT COUNT(*) FROM child_jobs WHERE batch_id = $1"
    )
    .bind(batch.batch_id)
    .fetch_one(&pool)
    .await
    .unwrap();

    assert_eq!(job_count, 40);

    // Verify batch metadata
    let (total, pending): (i32, i32) = sqlx::query_as(
        "SELECT total_jobs, pending_jobs FROM batch_jobs WHERE id = $1"
    )
    .bind(batch.batch_id)
    .fetch_one(&pool)
    .await
    .unwrap();

    assert_eq!(total, 40);
    assert_eq!(pending, 40);
}

// ============================================================================
// CONNECTION POOL STRESS
// ============================================================================

#[sqlx::test]
async fn test_spawn_batches_rapid_fire(pool: PgPool) {
    run_migrations(&pool).await;
    let spawner = Arc::new(JobSpawner::new(pool.clone()));

    // Rapidly create 30 batches without waiting
    let mut handles = vec![];

    for i in 0..30 {
        let spawner_clone = Arc::clone(&spawner);
        let handle = tokio::spawn(async move {
            let assets = vec![Asset {
                symbol: format!("RAPID{}", i),
                data_file: PathBuf::from(format!("/test/RAPID{}.parquet", i)),
            }];
            spawner_clone
                .spawn_batch(assets, vec![ModelType::DQN])
                .await
        });
        handles.push(handle);
    }

    // All should succeed
    for (i, handle) in handles.into_iter().enumerate() {
        let result = handle.await.unwrap();
        assert!(result.is_ok(), "Batch {} failed", i);
    }

    let count: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM batch_jobs")
        .fetch_one(&pool)
        .await
        .unwrap();
    assert_eq!(count, 30);
}

// ============================================================================
// EDGE CASES
// ============================================================================

#[sqlx::test]
async fn test_maximum_batch_size(pool: PgPool) {
    run_migrations(&pool).await;
    let spawner = JobSpawner::new(pool.clone());

    // 100 assets × 4 models = 400 jobs
    let assets: Vec<Asset> = (0..100)
        .map(|i| Asset {
            symbol: format!("MAX{}", i),
            data_file: PathBuf::from(format!("/test/MAX{}.parquet", i)),
        })
        .collect();

    let models = vec![ModelType::DQN, ModelType::PPO, ModelType::MAMBA, ModelType::TFT];

    let start = Instant::now();
    let batch = spawner.spawn_batch(assets, models).await.unwrap();
    let elapsed = start.elapsed();

    println!("400-job batch created in {:?}", elapsed);

    // Verify
    let count: i64 = sqlx::query_scalar(
        "SELECT COUNT(*) FROM child_jobs WHERE batch_id = $1"
    )
    .bind(batch.batch_id)
    .fetch_one(&pool)
    .await
    .unwrap();

    assert_eq!(count, 400);

    // Should complete in reasonable time (<1s)
    assert!(elapsed.as_secs() < 5, "Large batch too slow: {:?}", elapsed);
}

#[sqlx::test]
async fn test_unicode_asset_symbols(pool: PgPool) {
    run_migrations(&pool).await;
    let spawner = JobSpawner::new(pool.clone());

    let assets = vec![Asset {
        symbol: "测试符号".to_string(), // Chinese characters
        data_file: PathBuf::from("/test/unicode.parquet"),
    }];

    let result = spawner
        .spawn_batch(assets, vec![ModelType::DQN])
        .await;

    // Should handle gracefully (may succeed or fail depending on DB encoding)
    let _ = result;
}

#[sqlx::test]
async fn test_very_long_file_paths(pool: PgPool) {
    run_migrations(&pool).await;
    let spawner = JobSpawner::new(pool.clone());

    let long_path = "/very/long/path/".to_string() + &"subdir/".repeat(50) + "file.parquet";

    let assets = vec![Asset {
        symbol: "ES.FUT".to_string(),
        data_file: PathBuf::from(long_path),
    }];

    let result = spawner
        .spawn_batch(assets, vec![ModelType::DQN])
        .await;

    assert!(result.is_ok());
}

#[sqlx::test]
async fn test_special_characters_in_paths(pool: PgPool) {
    run_migrations(&pool).await;
    let spawner = JobSpawner::new(pool.clone());

    let assets = vec![Asset {
        symbol: "ES.FUT".to_string(),
        data_file: PathBuf::from("/test/data (2024)/ES FUT [180d].parquet"),
    }];

    let result = spawner
        .spawn_batch(assets, vec![ModelType::DQN])
        .await;

    assert!(result.is_ok());
}

#[sqlx::test]
async fn test_idempotency_check(pool: PgPool) {
    run_migrations(&pool).await;
    let spawner = JobSpawner::new(pool.clone());

    let assets = vec![Asset {
        symbol: "ES.FUT".to_string(),
        data_file: PathBuf::from("/test/ES.parquet"),
    }];

    // Create same batch twice
    let batch1 = spawner
        .spawn_batch(assets.clone(), vec![ModelType::DQN])
        .await
        .unwrap();

    let batch2 = spawner
        .spawn_batch(assets, vec![ModelType::DQN])
        .await
        .unwrap();

    // Should create separate batches (no built-in idempotency)
    assert_ne!(batch1.batch_id, batch2.batch_id);

    let count: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM batch_jobs")
        .fetch_one(&pool)
        .await
        .unwrap();
    assert_eq!(count, 2);
}