use crate::AutomationError;
use std::process::Command;
use tracing::info;

/// Configuration for virtual display
#[derive(Debug, Clone)]
pub struct VirtualDisplayConfig {
    pub width: u32,
    pub height: u32,
    pub color_depth: u32,
    pub refresh_rate: u32,
    pub driver_path: Option<String>,
}

impl Default for VirtualDisplayConfig {
    fn default() -> Self {
        Self {
            width: 1920,
            height: 1080,
            color_depth: 32,
            refresh_rate: 60,
            driver_path: None,
        }
    }
}

/// Manages virtual display for headless UI automation
pub struct VirtualDisplayManager {
    pub config: VirtualDisplayConfig,
    session_id: Option<u32>,
    is_initialized: bool,
}

impl VirtualDisplayManager {
    pub fn new(config: VirtualDisplayConfig) -> Self {
        Self {
            config,
            session_id: None,
            is_initialized: false,
        }
    }

    /// Initialize virtual display using Windows Virtual Display Driver
    pub fn initialize(&mut self) -> Result<(), AutomationError> {
        info!(
            "Initializing virtual display: {}x{}",
            self.config.width, self.config.height
        );

        // For MVP, we'll detect if we're in a headless environment
        // and set up accordingly
        if is_headless_environment() {
            info!("Headless environment detected, setting up virtual session");
            self.session_id = Some(0); // Virtual session ID
            self.create_virtual_session()?;
        } else {
            // Get current session ID from environment or use default
            self.session_id = Some(1);
            info!("Using session ID: {:?}", self.session_id);
        }

        // Mark as initialized
        self.is_initialized = true;
        info!("Virtual display initialized");

        Ok(())
    }

    /// Create a virtual display context
    #[allow(dead_code)]
    fn create_virtual_display(&mut self) -> Result<(), AutomationError> {
        // For the MVP, we'll use a simpler approach that doesn't require
        // direct Windows API calls that may not be available
        info!("Creating virtual display context");

        // The actual display creation would happen here if we had
        // a virtual display driver installed
        if self.config.driver_path.is_some() {
            info!("Virtual display driver configured, would use driver-based display");
        } else {
            info!("No driver configured, using default virtual session");
        }

        Ok(())
    }

    /// Create a memory-based display as fallback
    #[allow(dead_code)]
    fn create_memory_display(&mut self) -> Result<(), AutomationError> {
        // Simplified approach for MVP
        info!("Setting up memory-based virtual display");

        // In a real implementation, we would:
        // 1. Create a memory device context
        // 2. Set up a bitmap for rendering
        // 3. Configure the display properties

        self.is_initialized = true;
        Ok(())
    }

    /// Create a virtual session for headless operation
    fn create_virtual_session(&mut self) -> Result<(), AutomationError> {
        // This would typically involve:
        // 1. Creating a new window station
        // 2. Creating a new desktop
        // 3. Setting up the session for UI automation

        // For MVP, we'll use a simpler approach
        info!("Setting up virtual session for headless operation");

        // Ensure we have a valid window station and desktop
        // This is simplified - full implementation would create new ones
        Ok(())
    }

    /// Install virtual display driver if needed
    pub fn install_driver(&self) -> Result<(), AutomationError> {
        if let Some(driver_path) = &self.config.driver_path {
            info!("Installing virtual display driver from: {}", driver_path);

            let output = Command::new("pnputil")
                .args(["/add-driver", driver_path, "/install"])
                .output()
                .map_err(|e| {
                    AutomationError::PlatformError(format!("Failed to install driver: {e}"))
                })?;

            if !output.status.success() {
                let stderr = String::from_utf8_lossy(&output.stderr);
                return Err(AutomationError::PlatformError(format!(
                    "Driver installation failed: {stderr}"
                )));
            }

            info!("Virtual display driver installed successfully");
        }
        Ok(())
    }

    /// Check if virtual display is available
    pub fn is_available(&self) -> bool {
        self.is_initialized
    }

    /// Get the current session ID
    pub fn get_session_id(&self) -> Option<u32> {
        self.session_id
    }

    /// Cleanup virtual display resources
    pub fn cleanup(&mut self) {
        self.is_initialized = false;
        info!("Virtual display cleaned up");
    }
}

impl Drop for VirtualDisplayManager {
    fn drop(&mut self) {
        self.cleanup();
    }
}

/// Helper to check if we're running in a headless environment
pub fn is_headless_environment() -> bool {
    // Check environment variables that might indicate headless operation
    if let Ok(val) = std::env::var("TERMINATOR_HEADLESS") {
        return val.to_lowercase() == "true" || val == "1";
    }

    // Additional checks could be added here for:
    // - Checking if running as a service
    // - Detecting container environments
    // - Checking for remote sessions

    false
}

/// Configuration for running terminator in virtual/headless mode
#[derive(Debug, Clone)]
pub struct HeadlessConfig {
    pub use_virtual_display: bool,
    pub virtual_display_config: VirtualDisplayConfig,
    pub fallback_to_memory: bool,
}

impl Default for HeadlessConfig {
    fn default() -> Self {
        Self {
            use_virtual_display: is_headless_environment(),
            virtual_display_config: VirtualDisplayConfig::default(),
            fallback_to_memory: true,
        }
    }
}
