use std::collections::HashMap;
use thiserror::Error;

#[derive(Error, Debug)]
pub enum ServiceManagerError {
    #[error("Service '{0}' not found")]
    ServiceNotFound(String),
    #[error("Service '{0}' already exists")]
    ServiceAlreadyExists(String),
    #[error("Failed to start service '{0}': {1}")]
    StartFailed(String, String),
    #[error("Failed to stop service '{0}': {1}")]
    StopFailed(String, String),
    #[error("Failed to restart service '{0}': {1}")]
    RestartFailed(String, String),
    #[error("Failed to get logs for service '{0}': {1}")]
    LogsFailed(String, String),
    #[error("IO error: {0}")]
    IoError(#[from] std::io::Error),
    #[error("Service manager error: {0}")]
    Other(String),
}

#[derive(Debug, Clone)]
pub struct ServiceConfig {
    pub name: String,
    pub binary_path: String,
    pub args: Vec<String>,
    pub working_directory: Option<String>,
    pub environment: HashMap<String, String>,
    pub auto_restart: bool,
}

#[derive(Debug, Clone, PartialEq)]
pub enum ServiceStatus {
    Running,
    Stopped,
    Failed,
    Unknown,
}

pub trait ServiceManager: Send + Sync {
    /// Check if a service exists
    fn exists(&self, service_name: &str) -> Result<bool, ServiceManagerError>;

    /// Start a service with the given configuration
    fn start(&self, config: &ServiceConfig) -> Result<(), ServiceManagerError>;

    /// Start an existing service by name (load existing plist/config)
    fn start_existing(&self, service_name: &str) -> Result<(), ServiceManagerError>;

    /// Start a service and wait for confirmation that it's running or failed
    fn start_and_confirm(
        &self,
        config: &ServiceConfig,
        timeout_secs: u64,
    ) -> Result<(), ServiceManagerError>;

    /// Start an existing service and wait for confirmation that it's running or failed
    fn start_existing_and_confirm(
        &self,
        service_name: &str,
        timeout_secs: u64,
    ) -> Result<(), ServiceManagerError>;

    /// Stop a service by name
    fn stop(&self, service_name: &str) -> Result<(), ServiceManagerError>;

    /// Restart a service by name
    fn restart(&self, service_name: &str) -> Result<(), ServiceManagerError>;

    /// Get the status of a service
    fn status(&self, service_name: &str) -> Result<ServiceStatus, ServiceManagerError>;

    /// Get logs for a service
    fn logs(&self, service_name: &str, lines: Option<usize>)
        -> Result<String, ServiceManagerError>;

    /// List all managed services
    fn list(&self) -> Result<Vec<String>, ServiceManagerError>;

    /// Remove a service configuration (stop if running)
    fn remove(&self, service_name: &str) -> Result<(), ServiceManagerError>;
}

// Platform-specific implementations
#[cfg(target_os = "macos")]
mod launchctl;
#[cfg(target_os = "macos")]
pub use launchctl::LaunchctlServiceManager;

#[cfg(target_os = "linux")]
mod systemd;
#[cfg(target_os = "linux")]
pub use systemd::SystemdServiceManager;

mod zinit;
pub use zinit::ZinitServiceManager;

#[cfg(feature = "rhai")]
pub mod rhai;

/// Discover available zinit socket paths
///
/// This function checks for zinit sockets in the following order:
/// 1. Environment variable ZINIT_SOCKET_PATH (if set)
/// 2. Common socket locations with connectivity testing
///
/// # Returns
///
/// Returns the first working socket path found, or None if no working zinit server is detected.
#[cfg(target_os = "linux")]
fn discover_zinit_socket() -> Option<String> {
    // First check environment variable
    if let Ok(env_socket_path) = std::env::var("ZINIT_SOCKET_PATH") {
        log::debug!("Checking ZINIT_SOCKET_PATH: {}", env_socket_path);
        if test_zinit_socket(&env_socket_path) {
            log::info!(
                "Using zinit socket from ZINIT_SOCKET_PATH: {}",
                env_socket_path
            );
            return Some(env_socket_path);
        } else {
            log::warn!(
                "ZINIT_SOCKET_PATH specified but socket is not accessible: {}",
                env_socket_path
            );
        }
    }

    // Try common socket locations
    let common_paths = [
        "/var/run/zinit.sock",
        "/tmp/zinit.sock",
        "/run/zinit.sock",
        "./zinit.sock",
    ];

    log::debug!("Discovering zinit socket from common locations...");
    for path in &common_paths {
        log::debug!("Testing socket path: {}", path);
        if test_zinit_socket(path) {
            log::info!("Found working zinit socket at: {}", path);
            return Some(path.to_string());
        }
    }

    log::debug!("No working zinit socket found");
    None
}

/// Test if a zinit socket is accessible and responsive
///
/// This function attempts to create a ZinitServiceManager and perform a basic
/// connectivity test by listing services.
#[cfg(target_os = "linux")]
fn test_zinit_socket(socket_path: &str) -> bool {
    // Check if socket file exists first
    if !std::path::Path::new(socket_path).exists() {
        log::debug!("Socket file does not exist: {}", socket_path);
        return false;
    }

    // Try to create a manager and test basic connectivity
    match ZinitServiceManager::new(socket_path) {
        Ok(manager) => {
            // Test basic connectivity by trying to list services
            match manager.list() {
                Ok(_) => {
                    log::debug!("Socket {} is responsive", socket_path);
                    true
                }
                Err(e) => {
                    log::debug!("Socket {} exists but not responsive: {}", socket_path, e);
                    false
                }
            }
        }
        Err(e) => {
            log::debug!("Failed to create manager for socket {}: {}", socket_path, e);
            false
        }
    }
}

/// Create a service manager appropriate for the current platform
///
/// - On macOS: Uses launchctl for service management
/// - On Linux: Uses zinit for service management with systemd fallback
///
/// # Returns
///
/// Returns a Result containing the service manager or an error if initialization fails.
/// On Linux, it first tries to discover a working zinit socket. If no zinit server is found,
/// it will fall back to systemd.
///
/// # Environment Variables
///
/// - `ZINIT_SOCKET_PATH`: Specifies the zinit socket path (Linux only)
///
/// # Errors
///
/// Returns `ServiceManagerError` if:
/// - The platform is not supported (Windows, etc.)
/// - Service manager initialization fails on all available backends
pub fn create_service_manager() -> Result<Box<dyn ServiceManager>, ServiceManagerError> {
    #[cfg(target_os = "macos")]
    {
        Ok(Box::new(LaunchctlServiceManager::new()))
    }
    #[cfg(target_os = "linux")]
    {
        // Try to discover a working zinit socket
        if let Some(socket_path) = discover_zinit_socket() {
            match ZinitServiceManager::new(&socket_path) {
                Ok(zinit_manager) => {
                    log::info!("Using zinit service manager with socket: {}", socket_path);
                    return Ok(Box::new(zinit_manager));
                }
                Err(zinit_error) => {
                    log::warn!(
                        "Failed to create zinit manager for discovered socket {}: {}",
                        socket_path,
                        zinit_error
                    );
                }
            }
        } else {
            log::info!("No running zinit server detected. To use zinit, start it with: zinit -s /tmp/zinit.sock init");
        }

        // Fallback to systemd
        log::info!("Falling back to systemd service manager");
        Ok(Box::new(SystemdServiceManager::new()))
    }
    #[cfg(not(any(target_os = "macos", target_os = "linux")))]
    {
        Err(ServiceManagerError::Other(
            "Service manager not implemented for this platform".to_string(),
        ))
    }
}

/// Create a service manager for zinit with a custom socket path
///
/// This is useful when zinit is running with a non-default socket path
pub fn create_zinit_service_manager(
    socket_path: &str,
) -> Result<Box<dyn ServiceManager>, ServiceManagerError> {
    Ok(Box::new(ZinitServiceManager::new(socket_path)?))
}

/// Create a service manager for systemd (Linux alternative)
///
/// This creates a systemd-based service manager as an alternative to zinit on Linux
#[cfg(target_os = "linux")]
pub fn create_systemd_service_manager() -> Box<dyn ServiceManager> {
    Box::new(SystemdServiceManager::new())
}

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

    #[test]
    fn test_create_service_manager() {
        // This test ensures the service manager can be created without panicking
        let result = create_service_manager();
        assert!(result.is_ok(), "Service manager creation should succeed");
    }

    #[cfg(target_os = "linux")]
    #[test]
    fn test_socket_discovery_with_env_var() {
        // Test that environment variable is respected
        std::env::set_var("ZINIT_SOCKET_PATH", "/test/path.sock");

        // The discover function should check the env var first
        // Since the socket doesn't exist, it should return None, but we can't test
        // the actual discovery logic without a real socket

        std::env::remove_var("ZINIT_SOCKET_PATH");
    }

    #[cfg(target_os = "linux")]
    #[test]
    fn test_socket_discovery_without_env_var() {
        // Ensure env var is not set
        std::env::remove_var("ZINIT_SOCKET_PATH");

        // The discover function should try common paths
        // Since no zinit is running, it should return None
        let result = discover_zinit_socket();

        // This is expected to be None in test environment
        assert!(
            result.is_none(),
            "Should return None when no zinit server is running"
        );
    }
}