ubiquity-core 0.1.1

//! Local command execution implementation using tokio::process

use async_trait::async_trait;
use futures::Stream;
use std::pin::Pin;
use std::process::Stdio;
use std::sync::Arc;
use std::time::Instant;
use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
use tokio::process::Command;
use tokio::sync::{mpsc, oneshot};
use tracing::error;
use uuid::Uuid;

use crate::command::{
    CommandContext, CommandEvent, CommandExecutor, CommandHandle, CommandRequest, CommandResult,
};
use crate::error::UbiquityError;

/// Local command executor using native OS processes
pub struct LocalCommandExecutor {
    context: Arc<CommandContext>,
    event_buffer_size: usize,
}

impl LocalCommandExecutor {
    pub fn new() -> Self {
        Self {
            context: Arc::new(CommandContext::new()),
            event_buffer_size: 1024,
        }
    }

    pub fn with_event_buffer_size(mut self, size: usize) -> Self {
        self.event_buffer_size = size;
        self
    }

    async fn execute_process(
        request: CommandRequest,
        event_tx: mpsc::Sender<CommandEvent>,
        cancel_rx: mpsc::Receiver<()>,
        status_rx: mpsc::Receiver<oneshot::Sender<CommandResult>>,
    ) -> Result<(), UbiquityError> {
        let start_time = Instant::now();
        let command_id = request.id;

        // Send start event
        event_tx
            .send(CommandEvent::Started {
                command_id,
                command: request.command.clone(),
                args: request.args.clone(),
                timestamp: chrono::Utc::now(),
            })
            .await
            .map_err(|_| UbiquityError::Internal("Failed to send start event".to_string()))?;

        // Build the command
        let mut cmd = Command::new(&request.command);
        cmd.args(&request.args);
        cmd.stdout(Stdio::piped());
        cmd.stderr(Stdio::piped());
        cmd.stdin(Stdio::piped());

        // Set environment variables
        for (key, value) in &request.env {
            cmd.env(key, value);
        }

        // Set working directory
        if let Some(dir) = &request.working_dir {
            cmd.current_dir(dir);
        }

        // Spawn the process
        let mut child = cmd
            .spawn()
            .map_err(|e| UbiquityError::CommandExecution(format!("Failed to spawn process: {}", e)))?;

        // Get handles to stdio
        let stdout = child
            .stdout
            .take()
            .ok_or_else(|| UbiquityError::Internal("Failed to capture stdout".to_string()))?;
        let stderr = child
            .stderr
            .take()
            .ok_or_else(|| UbiquityError::Internal("Failed to capture stderr".to_string()))?;
        let mut stdin = child
            .stdin
            .take()
            .ok_or_else(|| UbiquityError::Internal("Failed to capture stdin".to_string()))?;

        // Write stdin if provided
        if let Some(input) = &request.stdin {
            stdin
                .write_all(input.as_bytes())
                .await
                .map_err(|e| UbiquityError::CommandExecution(format!("Failed to write stdin: {}", e)))?;
            stdin.shutdown().await.ok();
        }

        // Create readers for stdout and stderr
        let stdout_reader = BufReader::new(stdout);
        let stderr_reader = BufReader::new(stderr);

        // Collect output
        let collected_stdout;
        let collected_stderr;

        // Create tasks for reading output
        let event_tx_stdout = event_tx.clone();
        let event_tx_stderr = event_tx.clone();

        let stdout_task = tokio::spawn(async move {
            let mut lines = stdout_reader.lines();
            let mut output = Vec::new();
            while let Ok(Some(line)) = lines.next_line().await {
                output.push(line.clone());
                let _ = event_tx_stdout
                    .send(CommandEvent::Stdout {
                        command_id,
                        data: line,
                        timestamp: chrono::Utc::now(),
                    })
                    .await;
            }
            output
        });

        let stderr_task = tokio::spawn(async move {
            let mut lines = stderr_reader.lines();
            let mut output = Vec::new();
            while let Ok(Some(line)) = lines.next_line().await {
                output.push(line.clone());
                let _ = event_tx_stderr
                    .send(CommandEvent::Stderr {
                        command_id,
                        data: line,
                        timestamp: chrono::Utc::now(),
                    })
                    .await;
            }
            output
        });

        // Create a task to handle the process
        let process_task = tokio::spawn(async move {
            child.wait().await
        });

        // Create cancellation and status handling
        let (cancel_tx, mut cancel_rx_internal) = mpsc::channel::<()>(1);
        let (status_tx_internal, mut status_rx_internal) = mpsc::channel::<oneshot::Sender<CommandResult>>(1);

        // Forward external cancel/status requests to internal channels
        let cancel_forward = tokio::spawn(async move {
            let mut cancel_rx = cancel_rx;
            while let Some(()) = cancel_rx.recv().await {
                let _ = cancel_tx.send(()).await;
            }
        });

        let status_forward = tokio::spawn(async move {
            let mut status_rx = status_rx;
            while let Some(tx) = status_rx.recv().await {
                let _ = status_tx_internal.send(tx).await;
            }
        });

        // Clone the handle for later use
        let process_task_handle = process_task.abort_handle();
        
        // Wait for completion, cancellation, or timeout
        let result = tokio::select! {
            // Process completed normally
            exit_status = process_task => {
                match exit_status {
                    Ok(Ok(status)) => {
                        let exit_code = status.code().unwrap_or(-1);
                        let duration_ms = start_time.elapsed().as_millis() as u64;
                        
                        // Wait for output collection
                        collected_stdout = stdout_task.await.unwrap_or_default();
                        collected_stderr = stderr_task.await.unwrap_or_default();
                        
                        event_tx
                            .send(CommandEvent::Completed {
                                command_id,
                                exit_code,
                                duration_ms,
                                timestamp: chrono::Utc::now(),
                            })
                            .await
                            .ok();
                        
                        Ok(CommandResult {
                            id: command_id,
                            exit_code: Some(exit_code),
                            stdout: collected_stdout.join("\n"),
                            stderr: collected_stderr.join("\n"),
                            duration_ms,
                            cancelled: false,
                        })
                    }
                    Ok(Err(e)) => {
                        let duration_ms = start_time.elapsed().as_millis() as u64;
                        let error_msg = format!("Process error: {}", e);
                        
                        event_tx
                            .send(CommandEvent::Failed {
                                command_id,
                                error: error_msg.clone(),
                                duration_ms,
                                timestamp: chrono::Utc::now(),
                            })
                            .await
                            .ok();
                        
                        Err(UbiquityError::CommandExecution(error_msg))
                    }
                    Err(e) => {
                        let duration_ms = start_time.elapsed().as_millis() as u64;
                        let error_msg = format!("Task join error: {}", e);
                        
                        event_tx
                            .send(CommandEvent::Failed {
                                command_id,
                                error: error_msg.clone(),
                                duration_ms,
                                timestamp: chrono::Utc::now(),
                            })
                            .await
                            .ok();
                        
                        Err(UbiquityError::Internal(error_msg))
                    }
                }
            }
            
            // Cancellation requested
            _ = cancel_rx_internal.recv() => {
                let duration_ms = start_time.elapsed().as_millis() as u64;
                
                // Try to terminate the process
                if let Ok(mut child) = cmd.spawn() {
                    let _ = child.kill().await;
                }
                
                // Cancel output tasks
                stdout_task.abort();
                stderr_task.abort();
                process_task_handle.abort();
                
                event_tx
                    .send(CommandEvent::Cancelled {
                        command_id,
                        duration_ms,
                        timestamp: chrono::Utc::now(),
                    })
                    .await
                    .ok();
                
                Ok(CommandResult {
                    id: command_id,
                    exit_code: None,
                    stdout: String::new(),
                    stderr: String::new(),
                    duration_ms,
                    cancelled: true,
                })
            }
            
            // Timeout
            _ = async {
                if let Some(timeout_duration) = request.timeout {
                    tokio::time::sleep(timeout_duration).await
                } else {
                    // No timeout, wait forever
                    std::future::pending::<()>().await
                }
            } => {
                let duration_ms = start_time.elapsed().as_millis() as u64;
                
                // Try to terminate the process
                if let Ok(mut child) = cmd.spawn() {
                    let _ = child.kill().await;
                }
                
                // Cancel output tasks
                stdout_task.abort();
                stderr_task.abort();
                process_task_handle.abort();
                
                let error_msg = format!("Command timed out after {:?}", request.timeout.unwrap());
                event_tx
                    .send(CommandEvent::Failed {
                        command_id,
                        error: error_msg.clone(),
                        duration_ms,
                        timestamp: chrono::Utc::now(),
                    })
                    .await
                    .ok();
                
                Err(UbiquityError::Timeout(error_msg))
            }
        };

        // Clone result for status handler
        let result_for_status = result.as_ref().ok().cloned();
        
        // Handle status requests
        tokio::spawn(async move {
            while let Some(response_tx) = status_rx_internal.recv().await {
                if let Some(ref cmd_result) = result_for_status {
                    let _ = response_tx.send(cmd_result.clone());
                }
            }
        });

        // Clean up forwarding tasks
        cancel_forward.abort();
        status_forward.abort();

        result.map(|_| ())
    }
}

impl Default for LocalCommandExecutor {
    fn default() -> Self {
        Self::new()
    }
}

#[async_trait]
impl CommandExecutor for LocalCommandExecutor {
    async fn execute(
        &self,
        request: CommandRequest,
    ) -> Result<Pin<Box<dyn Stream<Item = CommandEvent> + Send>>, UbiquityError> {
        let (event_tx, event_rx) = mpsc::channel(self.event_buffer_size);
        let (cancel_tx, cancel_rx) = mpsc::channel(1);
        let (status_tx, status_rx) = mpsc::channel(1);

        let command_id = request.id;
        let handle = CommandHandle::new(command_id, cancel_tx, status_tx);
        
        // Register the command
        self.context.register(command_id, handle).await;

        // Spawn the execution task
        let context = self.context.clone();
        let event_tx_clone = event_tx.clone();
        tokio::spawn(async move {
            let result = Self::execute_process(request, event_tx_clone, cancel_rx, status_rx).await;
            
            // Unregister the command when done
            context.unregister(&command_id).await;
            
            if let Err(e) = result {
                error!("Command execution error: {}", e);
            }
        });

        Ok(Box::pin(tokio_stream::wrappers::ReceiverStream::new(event_rx)))
    }

    async fn cancel(&self, command_id: Uuid) -> Result<(), UbiquityError> {
        self.context.cancel(&command_id).await
    }

    async fn status(&self, command_id: Uuid) -> Result<Option<CommandResult>, UbiquityError> {
        if let Some(handle) = self.context.get(&command_id).await {
            Ok(Some(handle.status().await?))
        } else {
            Ok(None)
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use futures::StreamExt;

    #[tokio::test]
    async fn test_local_command_execution() {
        let executor = LocalCommandExecutor::new();
        let request = CommandRequest::new("echo").with_args(vec!["hello world".to_string()]);

        let mut stream = executor.execute(request).await.unwrap();
        let mut events = Vec::new();

        while let Some(event) = stream.next().await {
            events.push(event);
        }

        assert!(!events.is_empty());
        
        // Should have at least Started and Completed events
        let has_started = events.iter().any(|e| matches!(e, CommandEvent::Started { .. }));
        let has_completed = events.iter().any(|e| matches!(e, CommandEvent::Completed { .. }));
        
        assert!(has_started);
        assert!(has_completed);
    }

    #[tokio::test]
    async fn test_command_cancellation() {
        let executor = LocalCommandExecutor::new();
        let request = CommandRequest::new("sleep").with_args(vec!["10".to_string()]);
        let command_id = request.id;

        let mut stream = executor.execute(request).await.unwrap();

        // Wait a bit then cancel
        tokio::time::sleep(Duration::from_millis(100)).await;
        executor.cancel(command_id).await.unwrap();

        let mut cancelled = false;
        while let Some(event) = stream.next().await {
            if matches!(event, CommandEvent::Cancelled { .. }) {
                cancelled = true;
                break;
            }
        }

        assert!(cancelled);
    }

    #[tokio::test]
    async fn test_command_timeout() {
        let executor = LocalCommandExecutor::new();
        let request = CommandRequest::new("sleep")
            .with_args(vec!["10".to_string()])
            .with_timeout(Duration::from_millis(100));

        let mut stream = executor.execute(request).await.unwrap();
        let mut timed_out = false;

        while let Some(event) = stream.next().await {
            if let CommandEvent::Failed { error, .. } = event {
                if error.contains("timed out") {
                    timed_out = true;
                    break;
                }
            }
        }

        assert!(timed_out);
    }

    #[tokio::test]
    async fn test_command_with_stdin() {
        let executor = LocalCommandExecutor::new();
        let request = CommandRequest::new("cat").with_stdin("test input data");

        let mut stream = executor.execute(request).await.unwrap();
        let mut stdout_data = String::new();

        while let Some(event) = stream.next().await {
            if let CommandEvent::Stdout { data, .. } = event {
                stdout_data.push_str(&data);
            }
        }

        assert_eq!(stdout_data.trim(), "test input data");
    }
}