use anyhow::Result;
use common_contracts::messages::{SyncStateCommand, TaskType, WorkflowEvent};
use common_contracts::workflow_types::TaskStatus;
use serde_json::json;
use std::sync::Arc;
use std::time::Duration;
use tokio::sync::Mutex;
use uuid::Uuid;
use workflow_orchestrator_service::dag_scheduler::DagScheduler;
use workflow_orchestrator_service::logging::LogBufferManager;
use workflow_orchestrator_service::state::AppState;
use workflow_orchestrator_service::workflow::WorkflowEngine;
use workflow_orchestrator_service::config::AppConfig;
use futures::stream::StreamExt;

// Note: This test requires a running NATS server.
// Set NATS_URL environment variable if needed, otherwise defaults to localhost:4222
#[tokio::test]
async fn test_workflow_rehydration_flow() -> Result<()> {
    // 1. Setup NATS
    let nats_url = std::env::var("NATS_URL").unwrap_or_else(|_| "nats://localhost:4222".to_string());
    let nats_client = async_nats::connect(&nats_url).await;
    
    if nats_client.is_err() {
        println!("Skipping test: NATS not available at {}", nats_url);
        return Ok(());
    }
    let nats_client = nats_client?;

    // 2. Setup AppState (Mocking Dependencies)
    let config = AppConfig {
        nats_addr: nats_url.clone(),
        data_persistence_service_url: "http://localhost:3001".to_string(), // Mock URL
        workflow_data_path: "/tmp/workflow_data".to_string(),
        server_port: 0,
    };

    let (log_tx, _) = tokio::sync::broadcast::channel(100);
    let log_manager = Arc::new(LogBufferManager::new("/tmp/workflow_logs"));
    
    let state = Arc::new(AppState::new(config, log_manager.clone(), log_tx).await?);
    
    let engine = WorkflowEngine::new(state.clone(), nats_client.clone());

    // 3. Construct a Fake Workflow State (In-Memory)
    let req_id = Uuid::new_v4();
    let task_id = "task:fake_analysis".to_string();

    let mut dag = DagScheduler::new(req_id, "init_commit".to_string());
    dag.add_node(
        task_id.clone(),
        Some("Fake Analysis".to_string()),
        TaskType::Analysis,
        "fake.routing".to_string(),
        json!({"some": "config"})
    );
    // Mark it as running so it captures stream
    dag.update_status(&task_id, TaskStatus::Running);

    // Insert into State
    state.workflows.insert(req_id, Arc::new(Mutex::new(dag)));

    // 4. Subscribe to Workflow Events (Simulating Frontend)
    let subject = common_contracts::subjects::NatsSubject::WorkflowProgress(req_id).to_string();
    let mut sub = nats_client.subscribe(subject.clone()).await?;

    // 5. Simulate Receiving Stream Data & Logs
    // In real world, MessageConsumer calls these. Here we call Engine methods directly 
    // to simulate "Consumer received NATS msg -> updated DAG".
    
    let log_msg = "[INFO] Starting deep analysis...".to_string();
    let content_part1 = "Analysis Part 1...".to_string();
    let content_part2 = "Analysis Part 2 [Done]".to_string();

    engine.handle_task_log(task_id.clone(), log_msg.clone(), req_id).await?;
    engine.handle_task_stream_update(task_id.clone(), content_part1.clone(), req_id).await?;
    engine.handle_task_stream_update(task_id.clone(), content_part2.clone(), req_id).await?;

    println!("State injected. Now simulating Page Refresh (SyncState)...");

    // 6. Simulate Page Refresh -> Send SyncStateCommand
    let sync_cmd = SyncStateCommand { request_id: req_id };
    
    // We can call handle_sync_state directly or publish command.
    // Let's call directly to ensure we test the logic, but verify the OUTPUT via NATS subscription.
    engine.handle_sync_state(sync_cmd).await?;

    // 7. Verify Snapshot Received on NATS
    let mut snapshot_received = false;
    
    // We might receive other events, loop until snapshot or timeout
    let timeout = tokio::time::sleep(Duration::from_secs(2));
    tokio::pin!(timeout);

    loop {
        tokio::select! {
            Some(msg) = sub.next() => {
                if let Ok(event) = serde_json::from_slice::<WorkflowEvent>(&msg.payload) {
                    match event {
                        WorkflowEvent::WorkflowStateSnapshot { task_states, .. } => {
                            println!("Received Snapshot!");
                            
                            // Verify Task State
                            if let Some(ts) = task_states.get(&task_id) {
                                // Check Logs
                                assert!(ts.logs.contains(&log_msg), "Snapshot missing logs");
                                
                                // Check Content
                                let full_content = format!("{}{}", content_part1, content_part2);
                                assert_eq!(ts.content.as_ref().unwrap(), &full_content, "Snapshot content mismatch");
                                
                                println!("Snapshot verification passed!");
                                snapshot_received = true;
                                break;
                            } else {
                                panic!("Task state not found in snapshot");
                            }
                        },
                        _ => println!("Ignored other event: {:?}", event),
                    }
                }
            }
            _ = &mut timeout => {
                break;
            }
        }
    }

    assert!(snapshot_received, "Did not receive WorkflowStateSnapshot within timeout");

    Ok(())
}