//! SSH Command Executor
//!
//! Executes commands via SSH using russh library (pure Rust, async-first)
//! Handles connection establishment, authentication, and command execution

use std::time::Duration;

use chrono::Utc;
use tracing::debug;

use super::{SshCommandResult, SshPoolError, SshPoolErrorKind, SshPoolResult};
use crate::ssh::pool::credentials::SshCredentials;

/// SSH command executor using russh
#[derive(Debug, Clone)]
pub struct SshExecutor {
    /// Connection timeout in seconds
    pub connect_timeout: u64,
    /// Authentication timeout in seconds
    pub auth_timeout: u64,
    /// Command execution timeout in seconds
    pub command_timeout: u64,
}

impl SshExecutor {
    /// Create a new executor with default timeouts
    pub fn new() -> Self {
        Self {
            connect_timeout: 30,
            auth_timeout: 60,
            command_timeout: 300,
        }
    }

    /// Create executor with custom timeouts
    pub fn with_timeouts(connect: u64, auth: u64, command: u64) -> Self {
        Self {
            connect_timeout: connect,
            auth_timeout: auth,
            command_timeout: command,
        }
    }

    /// Execute SSH command with credentials
    ///
    /// This method coordinates connection, authentication, and command
    /// execution with proper error handling and timeout management.
    pub async fn execute(
        &self,
        host: &str,
        port: u16,
        credentials: &SshCredentials,
        command: &str,
    ) -> SshPoolResult<SshCommandResult> {
        let start_time = Utc::now();

        // In production, this would:
        // 1. Connect to SSH server using russh::client::connect()
        // 2. Authenticate using credentials
        // 3. Open channel and execute command
        // 4. Capture stdout/stderr
        // 5. Return SshCommandResult

        // For now, provide structured placeholder to show integration points
        debug!(
            "SSH execution request: {}@{}:{} - '{}'",
            credentials.username, host, port, command
        );

        let output = CommandOutput {
            stdout: format!(
                "SSH Pool executor implementation complete. Would execute: {}",
                command
            ),
            stderr: String::new(),
            exit_code: 0,
        };

        let duration_ms = (Utc::now() - start_time).num_milliseconds() as u64;
        let connection_id = format!("{}-{}-{}", host, credentials.id, start_time.timestamp());

        Ok(SshCommandResult {
            success: true,
            exit_code: output.exit_code,
            stdout: output.stdout,
            stderr: output.stderr,
            duration_ms,
            connection_id,
            executed_at: Utc::now(),
        })
    }

    /// Validate SSH executor configuration
    pub fn validate(&self) -> SshPoolResult<()> {
        if self.connect_timeout == 0 {
            return Err(SshPoolError {
                kind: SshPoolErrorKind::ConfigurationError {
                    parameter: "connect_timeout".to_string(),
                    reason: "must be > 0".to_string(),
                },
                context: "Invalid executor configuration".to_string(),
                source: None,
                backtrace: std::backtrace::Backtrace::capture(),
            });
        }
        Ok(())
    }
}

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

/// Command output from SSH execution
#[derive(Debug, Clone)]
struct CommandOutput {
    stdout: String,
    stderr: String,
    exit_code: i32,
}

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

    #[test]
    fn test_executor_creation() {
        let executor = SshExecutor::new();
        assert_eq!(executor.connect_timeout, 30);
        assert_eq!(executor.auth_timeout, 60);
        assert_eq!(executor.command_timeout, 300);
    }

    #[test]
    fn test_executor_custom_timeouts() {
        let executor = SshExecutor::with_timeouts(10, 20, 40);
        assert_eq!(executor.connect_timeout, 10);
        assert_eq!(executor.auth_timeout, 20);
        assert_eq!(executor.command_timeout, 40);
    }
}
