use std::sync::Arc;
use std::time::Duration;

use surrealdb::{
    engine::remote::ws::{Client, Ws},
    opt::auth::Root,
    Surreal,
};
use tokio::time::{sleep, timeout};
use vapora_a2a::{
    bridge::CoordinatorBridge,
    protocol::{A2aMessage, A2aMessagePart, A2aTask, TaskState},
    task_manager::TaskManager,
};
use vapora_agents::{
    config::AgentConfig, coordinator::AgentCoordinator, messages::AgentMessage,
    messages::TaskCompleted, registry::AgentRegistry,
};

/// Setup test database connection
async fn setup_test_db() -> Surreal<Client> {
    let db = Surreal::new::<Ws>("127.0.0.1:8000")
        .await
        .expect("Failed to connect to SurrealDB");

    db.signin(Root {
        username: "root",
        password: "root",
    })
    .await
    .expect("Failed to sign in");

    db.use_ns("test")
        .use_db("vapora_a2a_integration_test")
        .await
        .expect("Failed to use namespace");

    db
}

/// Setup test NATS connection
async fn setup_test_nats() -> async_nats::Client {
    async_nats::connect("127.0.0.1:4222")
        .await
        .expect("Failed to connect to NATS")
}

/// Test 1: Task persistence - tasks survive restarts
#[tokio::test]
#[ignore] // Requires SurrealDB running
async fn test_task_persistence_after_restart() {
    let db = setup_test_db().await;
    let task_manager = Arc::new(TaskManager::new(db.clone()));

    let task = A2aTask {
        id: "persistence-test-123".to_string(),
        message: A2aMessage {
            role: "user".to_string(),
            parts: vec![A2aMessagePart::Text("Test persistence task".to_string())],
        },
        metadata: Default::default(),
    };

    // Create task
    task_manager
        .create(task)
        .await
        .expect("Failed to create task");

    // Simulate restart by creating new TaskManager instance
    let task_manager2 = Arc::new(TaskManager::new(db.clone()));

    // Verify task still exists
    let status = task_manager2
        .get("persistence-test-123")
        .await
        .expect("Failed to get status after restart");

    assert_eq!(status.id, "persistence-test-123");
    assert_eq!(status.state, TaskState::Waiting.as_str());

    // Cleanup
    let _ = db
        .query("DELETE FROM a2a_tasks WHERE task_id = $task_id")
        .bind(("task_id", "persistence-test-123"))
        .await;
}

/// Test 2: NATS task completion updates DB correctly
#[tokio::test]
#[ignore] // Requires SurrealDB + NATS running
async fn test_nats_task_completion_updates_db() {
    let db = setup_test_db().await;
    let nats = setup_test_nats().await;

    let task_manager = Arc::new(TaskManager::new(db.clone()));
    let registry = Arc::new(AgentRegistry::new(10));
    let config = AgentConfig::default();
    let coordinator = Arc::new(AgentCoordinator::new(config, registry).await.unwrap());

    let bridge = Arc::new(CoordinatorBridge::new(
        coordinator,
        task_manager.clone(),
        Some(nats.clone()),
    ));

    bridge
        .start_result_listener()
        .await
        .expect("Failed to start listener");

    let task_id = "nats-completion-test-456".to_string();

    // Create task
    let task = A2aTask {
        id: task_id.clone(),
        message: A2aMessage {
            role: "user".to_string(),
            parts: vec![A2aMessagePart::Text("Test NATS completion".to_string())],
        },
        metadata: Default::default(),
    };

    task_manager
        .create(task)
        .await
        .expect("Failed to create task");

    // Publish TaskCompleted message to NATS
    let task_completed = TaskCompleted {
        task_id: task_id.clone(),
        agent_id: "test-agent".to_string(),
        result: "Test output from agent".to_string(),
        artifacts: vec!["/path/to/artifact.txt".to_string()],
        tokens_used: 100,
        duration_ms: 500,
        completed_at: chrono::Utc::now(),
    };

    let message = AgentMessage::TaskCompleted(task_completed);
    nats.publish(
        "vapora.tasks.completed",
        serde_json::to_vec(&message).unwrap().into(),
    )
    .await
    .expect("Failed to publish");

    // Wait for DB update (give NATS subscriber time to process)
    sleep(Duration::from_millis(1000)).await;

    // Verify DB updated
    let status = task_manager
        .get(&task_id)
        .await
        .expect("Failed to get status");

    assert_eq!(status.state, TaskState::Completed.as_str());
    assert!(status.result.is_some());

    let result = status.result.unwrap();
    assert_eq!(result.message.parts.len(), 1);

    if let A2aMessagePart::Text(text) = &result.message.parts[0] {
        assert_eq!(text, "Test output from agent");
    } else {
        panic!("Expected text message part");
    }

    assert!(result.artifacts.is_some());
    assert_eq!(result.artifacts.as_ref().unwrap().len(), 1);

    // Cleanup
    let _ = db
        .query("DELETE FROM a2a_tasks WHERE task_id = $task_id")
        .bind(("task_id", task_id))
        .await;
}

/// Test 3: Task state transitions work correctly
#[tokio::test]
#[ignore] // Requires SurrealDB running
async fn test_task_state_transitions() {
    let db = setup_test_db().await;
    let task_manager = Arc::new(TaskManager::new(db.clone()));

    let task_id = "state-transition-test-789".to_string();

    let task = A2aTask {
        id: task_id.clone(),
        message: A2aMessage {
            role: "user".to_string(),
            parts: vec![A2aMessagePart::Text("Test state transitions".to_string())],
        },
        metadata: Default::default(),
    };

    // Create task (waiting state)
    task_manager
        .create(task)
        .await
        .expect("Failed to create task");

    let status = task_manager.get(&task_id).await.unwrap();
    assert_eq!(status.state, TaskState::Waiting.as_str());

    // Transition to working
    task_manager
        .update_state(&task_id, TaskState::Working)
        .await
        .expect("Failed to update to working");

    let status = task_manager.get(&task_id).await.unwrap();
    assert_eq!(status.state, TaskState::Working.as_str());

    // Complete task
    let result = vapora_a2a::protocol::A2aTaskResult {
        message: A2aMessage {
            role: "assistant".to_string(),
            parts: vec![A2aMessagePart::Text("Task completed".to_string())],
        },
        artifacts: None,
    };

    task_manager
        .complete(&task_id, result)
        .await
        .expect("Failed to complete task");

    let status = task_manager.get(&task_id).await.unwrap();
    assert_eq!(status.state, TaskState::Completed.as_str());
    assert!(status.result.is_some());

    // Cleanup
    let _ = db
        .query("DELETE FROM a2a_tasks WHERE task_id = $task_id")
        .bind(("task_id", task_id))
        .await;
}

/// Test 4: Task failure handling
#[tokio::test]
#[ignore] // Requires SurrealDB running
async fn test_task_failure_handling() {
    let db = setup_test_db().await;
    let task_manager = Arc::new(TaskManager::new(db.clone()));

    let task_id = "failure-test-999".to_string();

    let task = A2aTask {
        id: task_id.clone(),
        message: A2aMessage {
            role: "user".to_string(),
            parts: vec![A2aMessagePart::Text("Test failure handling".to_string())],
        },
        metadata: Default::default(),
    };

    task_manager
        .create(task)
        .await
        .expect("Failed to create task");

    // Fail task
    let error = vapora_a2a::protocol::A2aErrorObj {
        code: -1,
        message: "Test error message".to_string(),
    };

    task_manager
        .fail(&task_id, error)
        .await
        .expect("Failed to fail task");

    let status = task_manager.get(&task_id).await.unwrap();
    assert_eq!(status.state, TaskState::Failed.as_str());
    assert!(status.error.is_some());
    assert_eq!(status.error.unwrap().message, "Test error message");

    // Cleanup
    let _ = db
        .query("DELETE FROM a2a_tasks WHERE task_id = $task_id")
        .bind(("task_id", task_id))
        .await;
}

/// Test 5: End-to-end task dispatch with timeout
#[tokio::test]
#[ignore] // Requires SurrealDB + NATS + Agent running
async fn test_end_to_end_task_dispatch() {
    let db = setup_test_db().await;
    let nats = setup_test_nats().await;

    let task_manager = Arc::new(TaskManager::new(db.clone()));
    let registry = Arc::new(AgentRegistry::new(10));
    let config = AgentConfig::default();
    let coordinator = Arc::new(AgentCoordinator::new(config, registry).await.unwrap());

    let bridge = Arc::new(CoordinatorBridge::new(
        coordinator,
        task_manager.clone(),
        Some(nats.clone()),
    ));

    bridge
        .start_result_listener()
        .await
        .expect("Failed to start listener");

    let task = A2aTask {
        id: "e2e-test-task-001".to_string(),
        message: A2aMessage {
            role: "user".to_string(),
            parts: vec![A2aMessagePart::Text(
                "Create hello world function".to_string(),
            )],
        },
        metadata: Default::default(),
    };

    // Dispatch task
    let task_id = bridge
        .dispatch(task)
        .await
        .expect("Failed to dispatch task");

    // Poll for completion with timeout
    let result = timeout(Duration::from_secs(60), async {
        loop {
            let status = bridge
                .get_task(&task_id)
                .await
                .expect("Failed to get status");

            match task_state_from_str(&status.state) {
                TaskState::Completed => return Ok(status),
                TaskState::Failed => return Err(format!("Task failed: {:?}", status.error)),
                _ => {
                    sleep(Duration::from_millis(500)).await;
                }
            }
        }
    })
    .await;

    match result {
        Ok(Ok(status)) => {
            println!("Task completed successfully: {:?}", status);
            assert_eq!(status.state, TaskState::Completed.as_str());
        }
        Ok(Err(e)) => panic!("Task failed: {}", e),
        Err(_) => {
            println!(
                "Task did not complete within 60 seconds (this is expected if no agent is running)"
            );
            // Cleanup partial task
            let _ = db
                .query("DELETE FROM a2a_tasks WHERE task_id = $task_id")
                .bind(("task_id", task_id))
                .await;
        }
    }
}

// Helper to convert string to TaskState
fn task_state_from_str(s: &str) -> TaskState {
    match s {
        "waiting" => TaskState::Waiting,
        "working" => TaskState::Working,
        "completed" => TaskState::Completed,
        "failed" => TaskState::Failed,
        _ => TaskState::Waiting,
    }
}