use anyhow::Result;
use clap::Parser;
use tracing::{info, warn, error, Level};
use tracing_subscriber;
use caldav_sync::{Config, CalDavResult, SyncEngine};
use caldav_sync::nextcloud_import::{ImportEngine, ImportBehavior};
use caldav_sync::minicaldav_client::CalendarEvent;
use std::path::PathBuf;
use chrono::{Utc, Duration};


#[derive(Parser)]
#[command(name = "caldav-sync")]
#[command(about = "A CalDAV calendar synchronization tool")]
#[command(version)]
struct Cli {
    /// Configuration file path
    #[arg(short, long, default_value = "config/config.toml")]
    config: PathBuf,

    /// CalDAV server URL (overrides config file)
    #[arg(short, long)]
    server_url: Option<String>,

    /// Username for authentication (overrides config file)
    #[arg(short, long)]
    username: Option<String>,

    /// Password for authentication (overrides config file)
    #[arg(short, long)]
    password: Option<String>,

    /// Calendar name to sync (overrides config file)
    #[arg(long)]
    calendar: Option<String>,

    /// Enable debug logging
    #[arg(short, long)]
    debug: bool,

    /// Perform a one-time sync and exit
    #[arg(long)]
    once: bool,

    /// Force a full resynchronization
    #[arg(long)]
    full_resync: bool,

    /// List events and exit
    #[arg(long)]
    list_events: bool,

    /// List available calendars and exit
    #[arg(long)]
    list_calendars: bool,

    /// Use specific CalDAV approach (report-simple, propfind-depth, simple-propfind, multiget, report-filter, ical-export, zoho-export, zoho-events-list, zoho-events-direct)
    #[arg(long)]
    approach: Option<String>,

    /// Use specific calendar URL instead of discovering from config
    #[arg(long)]
    calendar_url: Option<String>,

    /// Show detailed import-relevant information for calendars
    #[arg(long)]
    import_info: bool,

    /// Import events into Nextcloud calendar
    #[arg(long)]
    import_nextcloud: bool,

    /// Target calendar name for Nextcloud import (overrides config)
    #[arg(long)]
    nextcloud_calendar: Option<String>,

    /// Import behavior: strict, strict_with_cleanup
    #[arg(long, default_value = "strict")]
    import_behavior: String,

    /// Dry run - show what would be imported without actually doing it
    #[arg(long)]
    dry_run: bool,

    /// List events from import target calendar and exit
    #[arg(long)]
    list_import_events: bool,
}

#[tokio::main]
async fn main() -> Result<()> {
    let cli = Cli::parse();

    // Initialize logging
    let log_level = if cli.debug { Level::DEBUG } else { Level::INFO };
    tracing_subscriber::fmt()
        .with_max_level(log_level)
        .with_target(false)
        .compact()
        .init();

    info!("Starting CalDAV synchronization tool v{}", env!("CARGO_PKG_VERSION"));

    // Load configuration
    let mut config = match Config::from_file(&cli.config) {
        Ok(config) => {
            info!("Loaded configuration from: {}", cli.config.display());
            config
        }
        Err(e) => {
            warn!("Failed to load config file: {}", e);
            info!("Using default configuration and environment variables");
            Config::from_env()?
        }
    };

    // Override configuration with command line arguments
    if let Some(ref server_url) = cli.server_url {
        config.server.url = server_url.clone();
    }
    if let Some(ref username) = cli.username {
        config.server.username = username.clone();
    }
    if let Some(ref password) = cli.password {
        config.server.password = password.clone();
    }
    if let Some(ref calendar) = cli.calendar {
        config.calendar.name = calendar.clone();
    }

    // Validate configuration
    if let Err(e) = config.validate() {
        error!("Configuration validation failed: {}", e);
        return Err(e.into());
    }

    info!("Server URL: {}", config.server.url);
    info!("Username: {}", config.server.username);
    info!("Calendar: {}", config.calendar.name);

    // Initialize and run synchronization
    match run_sync(config, &cli).await {
        Ok(_) => {
            info!("CalDAV synchronization completed successfully");
        }
        Err(e) => {
            error!("CalDAV synchronization failed: {}", e);
            return Err(e.into());
        }
    }

    Ok(())
}

async fn run_sync(config: Config, cli: &Cli) -> CalDavResult<()> {
    if cli.list_calendars {
        // List calendars and exit
        info!("Listing available calendars from server");
        
        if cli.import_info {
            println!("🔍 Import Analysis Report");
            println!("========================\n");
            
            // Show source calendars (current configuration)
            println!("📤 SOURCE CALENDARS (Zoho/Current Server)");
            println!("==========================================");
            
            // Get calendars from the source server - handle errors gracefully
            let source_calendars = match SyncEngine::new(config.clone()).await {
                Ok(sync_engine) => {
                    match sync_engine.client.discover_calendars().await {
                        Ok(calendars) => {
                            Some(calendars)
                        }
                        Err(e) => {
                            println!("⚠️ Failed to discover source calendars: {}", e);
                            println!("Source server may be unavailable or credentials may be incorrect.\n");
                            None
                        }
                    }
                }
                Err(e) => {
                    println!("⚠️ Failed to connect to source server: {}", e);
                    println!("Source server configuration may need checking.\n");
                    None
                }
            };
            
            let target_calendar_name = &config.calendar.name;
            
            if let Some(ref calendars) = source_calendars {
                println!("Found {} source calendars:", calendars.len());
                println!("Current source calendar: {}\n", target_calendar_name);
                
                for (i, calendar) in calendars.iter().enumerate() {
                    let is_target = calendar.name == *target_calendar_name 
                        || calendar.display_name.as_ref().map_or(false, |dn| dn == target_calendar_name);
                    
                    // Calendar header with target indicator
                    if is_target {
                        println!("  {}. {} 🎯 [CURRENT SOURCE]", i + 1, calendar.display_name.as_ref().unwrap_or(&calendar.name));
                    } else {
                        println!("  {}. {}", i + 1, calendar.display_name.as_ref().unwrap_or(&calendar.name));
                    }
                    
                    // Basic information
                    println!("     Name: {}", calendar.name);
                    println!("     URL: {}", calendar.url);
                    
                    if let Some(ref display_name) = calendar.display_name {
                        println!("     Display Name: {}", display_name);
                    }
                    
                    // Import-relevant information
                    if let Some(ref color) = calendar.color {
                        println!("     Color: {}", color);
                    }
                    
                    if let Some(ref description) = calendar.description {
                        println!("     Description: {}", description);
                    }
                    
                    if let Some(ref timezone) = calendar.timezone {
                        println!("     Timezone: {}", timezone);
                    }
                    
                    // Supported components - crucial for export compatibility
                    let components = &calendar.supported_components;
                    println!("     Supported Components: {}", components.join(", "));
                    
                    // Export suitability analysis
                    let supports_events = components.contains(&"VEVENT".to_string());
                    let supports_todos = components.contains(&"VTODO".to_string());
                    let supports_journals = components.contains(&"VJOURNAL".to_string());
                    
                    println!("     📤 Export Analysis:");
                    println!("        Event Support: {}", if supports_events { "✅ Yes" } else { "❌ No" });
                    println!("        Task Support: {}", if supports_todos { "✅ Yes" } else { "❌ No" });
                    println!("        Journal Support: {}", if supports_journals { "✅ Yes" } else { "❌ No" });
                    
                    // Server type detection
                    if calendar.url.contains("/zoho/") || calendar.url.contains("zoho.com") {
                        println!("        Server Type: 🔵 Zoho");
                        println!("        CalDAV Standard: ⚠️ Partially Compliant");
                        println!("        Special Features: Zoho-specific APIs available");
                    } else {
                        println!("        Server Type: 🔧 Generic CalDAV");
                        println!("        CalDAV Standard: ✅ Likely Compliant");
                    }
                    
                    println!();
                }
            } else {
                println!("⚠️ Could not retrieve source calendars");
                println!("Please check your source server configuration:\n");
                println!("  URL: {}", config.server.url);
                println!("  Username: {}", config.server.username);
                println!("  Calendar: {}\n", config.calendar.name);
            }
            
          // Show target import calendars if configured
            if let Some(ref import_config) = config.get_import_config() {
                println!("📥 TARGET IMPORT CALENDARS (Nextcloud/Destination)");
                println!("=================================================");
                
                println!("Configured target server: {}", import_config.target_server.url);
                println!("Configured target calendar: {}\n", import_config.target_calendar.name);
                
                // Create a temporary config for the target server
                let mut target_config = config.clone();
                target_config.server.url = import_config.target_server.url.clone();
                target_config.server.username = import_config.target_server.username.clone();
                target_config.server.password = import_config.target_server.password.clone();
                target_config.server.timeout = import_config.target_server.timeout;
                target_config.server.use_https = import_config.target_server.use_https;
                target_config.server.headers = import_config.target_server.headers.clone();
                
                println!("Attempting to connect to target server...");
                
                // Try to connect to target server and list calendars
                match SyncEngine::new(target_config).await {
                    Ok(target_sync_engine) => {
                        println!("✅ Successfully connected to target server!");
                        match target_sync_engine.client.discover_calendars().await {
                            Ok(target_calendars) => {
                                println!("Found {} target calendars:", target_calendars.len());
                                
                                for (i, calendar) in target_calendars.iter().enumerate() {
                                    let is_target = calendar.name == import_config.target_calendar.name 
                                        || calendar.display_name.as_ref().map_or(false, |dn| *dn == import_config.target_calendar.name);
                                    
                                    // Calendar header with target indicator
                                    if is_target {
                                        println!("  {}. {} 🎯 [IMPORT TARGET]", i + 1, calendar.display_name.as_ref().unwrap_or(&calendar.name));
                                    } else {
                                        println!("  {}. {}", i + 1, calendar.display_name.as_ref().unwrap_or(&calendar.name));
                                    }
                                    
                                    // Basic information
                                    println!("     Name: {}", calendar.name);
                                    println!("     URL: {}", calendar.url);
                                    
                                    if let Some(ref display_name) = calendar.display_name {
                                        println!("     Display Name: {}", display_name);
                                    }
                                    
                                    // Import-relevant information
                                    if let Some(ref color) = calendar.color {
                                        println!("     Color: {}", color);
                                    }
                                    
                                    if let Some(ref description) = calendar.description {
                                        println!("     Description: {}", description);
                                    }
                                    
                                    if let Some(ref timezone) = calendar.timezone {
                                        println!("     Timezone: {}", timezone);
                                    }
                                    
                                    // Supported components - crucial for import compatibility
                                    let components = &calendar.supported_components;
                                    println!("     Supported Components: {}", components.join(", "));
                                    
                                    // Import suitability analysis
                                    let supports_events = components.contains(&"VEVENT".to_string());
                                    let supports_todos = components.contains(&"VTODO".to_string());
                                    let supports_journals = components.contains(&"VJOURNAL".to_string());
                                    
                                    println!("     📥 Import Analysis:");
                                    println!("        Event Support: {}", if supports_events { "✅ Yes" } else { "❌ No" });
                                    println!("        Task Support: {}", if supports_todos { "✅ Yes" } else { "❌ No" });
                                    println!("        Journal Support: {}", if supports_journals { "✅ Yes" } else { "❌ No" });
                                    
                                    // Server type detection
                                    if calendar.url.contains("/remote.php/dav/calendars/") {
                                        println!("        Server Type: ☁️ Nextcloud");
                                        println!("        CalDAV Standard: ✅ RFC 4791 Compliant");
                                        println!("        Recommended: ✅ High compatibility");
                                        println!("        Special Features: Full SabreDAV support");
                                    } else {
                                        println!("        Server Type: 🔧 Generic CalDAV");
                                        println!("        CalDAV Standard: ✅ Likely Compliant");
                                    }
                                    
                                    // Additional Nextcloud-specific checks
                                    if calendar.url.contains("/remote.php/dav/calendars/") && supports_events {
                                        println!("        ✅ Ready for Nextcloud event import");
                                    } else if !supports_events {
                                        println!("        ⚠️ This calendar doesn't support events - not suitable for import");
                                    }
                                    
                                    println!();
                                }
                                
                                // Import compatibility summary
                                let target_calendar = target_calendars.iter()
                                    .find(|c| c.name == import_config.target_calendar.name 
                                        || c.display_name.as_ref().map_or(false, |dn| *dn == import_config.target_calendar.name));
                                
                                if let Some(target_cal) = target_calendar {
                                    let supports_events = target_cal.supported_components.contains(&"VEVENT".to_string());
                                    let is_nextcloud = target_cal.url.contains("/remote.php/dav/calendars/");
                                    
                                    println!("📋 IMPORT READINESS SUMMARY");
                                    println!("============================");
                                    println!("Target Calendar: {}", target_cal.display_name.as_ref().unwrap_or(&target_cal.name));
                                    println!("Supports Events: {}", if supports_events { "✅ Yes" } else { "❌ No" });
                                    println!("Server Type: {}", if is_nextcloud { "☁️ Nextcloud" } else { "🔧 Generic CalDAV" });
                                    
                                    if supports_events {
                                        if is_nextcloud {
                                            println!("Overall Status: ✅ Excellent - Nextcloud with full event support");
                                        } else {
                                            println!("Overall Status: ✅ Good - Generic CalDAV with event support");
                                        }
                                    } else {
                                        println!("Overall Status: ❌ Not suitable - No event support");
                                    }
                                } else {
                                    println!("⚠️ Target calendar '{}' not found on server", import_config.target_calendar.name);
                                    println!("Available calendars:");
                                    for calendar in &target_calendars {
                                        println!("  - {}", calendar.display_name.as_ref().unwrap_or(&calendar.name));
                                    }
                                }
                            }
                            Err(e) => {
                                println!("❌ Failed to discover calendars on target server: {}", e);
                                println!("The server connection was successful, but calendar discovery failed.");
                                println!("Please check your import configuration:");
                                println!("  URL: {}", import_config.target_server.url);
                                println!("  Username: {}", import_config.target_server.username);
                                println!("  Target Calendar: {}", import_config.target_calendar.name);
                            }
                        }
                    }
                    Err(e) => {
                        println!("❌ Failed to connect to target server: {}", e);
                        println!("Please check your import configuration:");
                        println!("  URL: {}", import_config.target_server.url);
                        println!("  Username: {}", import_config.target_server.username);
                        println!("  Target Calendar: {}", import_config.target_calendar.name);
                        
                        // Provide guidance based on the error
                        if e.to_string().contains("401") || e.to_string().contains("Unauthorized") {
                            println!("");
                            println!("💡 Troubleshooting tips:");
                            println!("  - Check username and password");
                            println!("  - For Nextcloud with 2FA, use app-specific passwords");
                            println!("  - Verify the URL format: https://your-nextcloud.com/remote.php/dav/calendars/username/");
                        } else if e.to_string().contains("404") || e.to_string().contains("Not Found") {
                            println!("");
                            println!("💡 Troubleshooting tips:");
                            println!("  - Verify the Nextcloud URL is correct");
                            println!("  - Check if CalDAV is enabled in Nextcloud settings");
                            println!("  - Ensure the username is correct (case-sensitive)");
                        } else if e.to_string().contains("timeout") || e.to_string().contains("connection") {
                            println!("");
                            println!("💡 Troubleshooting tips:");
                            println!("  - Check network connectivity");
                            println!("  - Verify the Nextcloud server is accessible");
                            println!("  - Try increasing timeout value in configuration");
                        }
                    }
                }
            } else {
                println!("📥 No import target configured");
                println!("To configure import target, add [import] section to config.toml:");
                println!("");
                println!("[import]");
                println!("[import.target_server]");
                println!("url = \"https://your-nextcloud.com/remote.php/dav/calendars/user\"");
                println!("username = \"your-username\"");
                println!("password = \"your-password\"");
                println!("[import.target_calendar]");
                println!("name = \"Imported-Zoho-Events\"");
                println!("enabled = true");
            }
        } else {
            // Regular calendar listing (original behavior) - only if not import_info
            let sync_engine = SyncEngine::new(config.clone()).await?;
            let calendars = sync_engine.client.discover_calendars().await?;
            
            println!("Found {} calendars:", calendars.len());
            for (i, calendar) in calendars.iter().enumerate() {
                println!("  {}. {}", i + 1, calendar.display_name.as_ref().unwrap_or(&calendar.name));
                println!("     Name: {}", calendar.name);
                println!("     URL: {}", calendar.url);
                if let Some(ref color) = calendar.color {
                    println!("     Color: {}", color);
                }
                if let Some(ref description) = calendar.description {
                    println!("     Description: {}", description);
                }
                if let Some(ref timezone) = calendar.timezone {
                    println!("     Timezone: {}", timezone);
                }
                println!("     Supported Components: {}", calendar.supported_components.join(", "));
                println!();
            }
        }
        
        return Ok(());
    }

    // Handle Nextcloud import
    if cli.import_nextcloud {
        info!("Starting Nextcloud import process");
        
        // Validate import configuration
        let import_config = match config.get_import_config() {
            Some(config) => config,
            None => {
                error!("No import target configured. Please add [import] section to config.toml");
                return Err(anyhow::anyhow!("Import configuration not found").into());
            }
        };

        // Parse import behavior
        let behavior = match cli.import_behavior.parse::<ImportBehavior>() {
            Ok(behavior) => behavior,
            Err(e) => {
                error!("Invalid import behavior '{}': {}", cli.import_behavior, e);
                return Err(anyhow::anyhow!("Invalid import behavior").into());
            }
        };

        // Override target calendar if specified via CLI
        let target_calendar_name = cli.nextcloud_calendar.as_ref()
            .unwrap_or(&import_config.target_calendar.name);

        info!("Importing to calendar: {}", target_calendar_name);
        info!("Import behavior: {}", behavior);
        info!("Dry run: {}", cli.dry_run);

        // Create import engine
        let import_engine = ImportEngine::new(import_config, behavior, cli.dry_run);

        // Get source events from the source calendar
        info!("Retrieving events from source calendar...");
        let mut source_sync_engine = match SyncEngine::new(config.clone()).await {
            Ok(engine) => engine,
            Err(e) => {
                error!("Failed to connect to source server: {}", e);
                return Err(e.into());
            }
        };

        // Perform sync to get events
        let _sync_result = match source_sync_engine.sync_full().await {
            Ok(result) => result,
            Err(e) => {
                error!("Failed to sync events from source: {}", e);
                return Err(e.into());
            }
        };

        let source_events = source_sync_engine.get_local_events();
        info!("Retrieved {} events from source calendar", source_events.len());

        if source_events.is_empty() {
            info!("No events found in source calendar to import");
            return Ok(());
        }

        // Convert source events to import events (Event type conversion needed)
        // TODO: For now, we'll simulate with test events since Event types might differ
        let import_events: Vec<caldav_sync::event::Event> = source_events
            .iter()
            .enumerate()
            .map(|(_i, event)| {
                // Convert CalendarEvent to Event for import
                // This is a simplified conversion - you may need to adjust based on actual Event structure
                caldav_sync::event::Event {
                    uid: event.id.clone(),
                    summary: event.summary.clone(),
                    description: event.description.clone(),
                    start: event.start,
                    end: event.end,
                    all_day: false, // TODO: Extract from event data
                    location: event.location.clone(),
                    status: caldav_sync::event::EventStatus::Confirmed, // TODO: Extract from event
                    event_type: caldav_sync::event::EventType::Public, // TODO: Extract from event
                    organizer: None, // TODO: Extract from event
                    attendees: Vec::new(), // TODO: Extract from event
                    recurrence: None, // TODO: Extract from event
                    alarms: Vec::new(), // TODO: Extract from event
                    properties: std::collections::HashMap::new(),
                    created: event.last_modified.unwrap_or_else(Utc::now),
                    last_modified: event.last_modified.unwrap_or_else(Utc::now),
                    sequence: 0, // TODO: Extract from event
                    timezone: event.start_tzid.clone(),
                }
            })
            .collect();

        // Perform import
        match import_engine.import_events(import_events).await {
            Ok(result) => {
                // Display import results
                println!("\n🎉 Import Completed Successfully!");
                println!("=====================================");
                println!("Target Calendar: {}", result.target_calendar);
                println!("Import Behavior: {}", result.behavior);
                println!("Dry Run: {}", if result.dry_run { "Yes" } else { "No" });
                println!();
                
                if let Some(duration) = result.duration() {
                    println!("Duration: {}ms", duration.num_milliseconds());
                }
                
                println!("Results:");
                println!("  Total events processed: {}", result.total_events);
                println!("  Successfully imported: {}", result.imported);
                println!("  Skipped: {}", result.skipped);
                println!("  Failed: {}", result.failed);
                println!("  Success rate: {:.1}%", result.success_rate());
                
                if !result.errors.is_empty() {
                    println!("\n⚠️ Errors encountered:");
                    for error in &result.errors {
                        println!("  - {}: {}", 
                               error.event_summary.as_deref().unwrap_or("Unknown event"),
                               error.message);
                    }
                }
                
                if !result.conflicts.is_empty() {
                    println!("\n🔄 Conflicts resolved:");
                    for conflict in &result.conflicts {
                        println!("  - {}: {:?}", conflict.event_summary, conflict.resolution);
                    }
                }
                
                if result.dry_run {
                    println!("\n💡 This was a dry run. No actual changes were made.");
                    println!("   Run without --dry-run to perform the actual import.");
                }
            }
            Err(e) => {
            error!("Import failed: {}", e);
            return Err(e.into());
        }
        }

        return Ok(());
    }

    // Handle listing events from import target calendar
    if cli.list_import_events {
        info!("Listing events from import target calendar");
        
        // Validate import configuration
        let import_config = match config.get_import_config() {
            Some(config) => config,
            None => {
                error!("No import target configured. Please add [import] section to config.toml");
                return Err(anyhow::anyhow!("Import configuration not found").into());
            }
        };

        // Override target calendar if specified via CLI
        let target_calendar_name = cli.nextcloud_calendar.as_ref()
            .unwrap_or(&import_config.target_calendar.name);

        println!("📅 Events from Import Target Calendar");
        println!("=====================================");
        println!("Target Server: {}", import_config.target_server.url);
        println!("Target Calendar: {}\n", target_calendar_name);

        // Create a temporary config for the target server
        let mut target_config = config.clone();
        target_config.server.url = import_config.target_server.url.clone();
        target_config.server.username = import_config.target_server.username.clone();
        target_config.server.password = import_config.target_server.password.clone();
        target_config.server.timeout = import_config.target_server.timeout;
        target_config.server.use_https = import_config.target_server.use_https;
        target_config.server.headers = import_config.target_server.headers.clone();
        target_config.calendar.name = target_calendar_name.clone();

        // Connect to target server
        let target_sync_engine = match SyncEngine::new(target_config).await {
            Ok(engine) => engine,
            Err(e) => {
                error!("Failed to connect to target server: {}", e);
                println!("❌ Failed to connect to target server: {}", e);
                println!("Please check your import configuration:");
                println!("  URL: {}", import_config.target_server.url);
                println!("  Username: {}", import_config.target_server.username);
                println!("  Target Calendar: {}", target_calendar_name);
                return Err(e.into());
            }
        };

        println!("✅ Successfully connected to target server!");

        // Discover calendars to find the target calendar URL
        let target_calendars = match target_sync_engine.client.discover_calendars().await {
            Ok(calendars) => calendars,
            Err(e) => {
                error!("Failed to discover calendars on target server: {}", e);
                println!("❌ Failed to discover calendars: {}", e);
                return Err(e.into());
            }
        };

        // Find the target calendar
        let target_calendar = target_calendars.iter()
            .find(|c| c.name == *target_calendar_name || c.display_name.as_ref().map_or(false, |dn| dn == target_calendar_name));

        let target_calendar = match target_calendar {
            Some(calendar) => {
                println!("✅ Found target calendar: {}", calendar.display_name.as_ref().unwrap_or(&calendar.name));
                calendar
            }
            None => {
                println!("❌ Target calendar '{}' not found on server", target_calendar_name);
                println!("Available calendars:");
                for calendar in &target_calendars {
                    println!("  - {}", calendar.display_name.as_ref().unwrap_or(&calendar.name));
                }
                return Err(anyhow::anyhow!("Target calendar not found").into());
            }
        };

        // Check if calendar supports events
        let supports_events = target_calendar.supported_components.contains(&"VEVENT".to_string());
        if !supports_events {
            println!("❌ Target calendar does not support events");
            println!("Supported components: {}", target_calendar.supported_components.join(", "));
            return Err(anyhow::anyhow!("Calendar does not support events").into());
        }

        // Set date range for event listing (past 30 days to next 30 days)
        let now = Utc::now();
        let start_date = now - Duration::days(30);
        let end_date = now + Duration::days(30);

        println!("\nRetrieving events from {} to {}...", 
                start_date.format("%Y-%m-%d"), 
                end_date.format("%Y-%m-%d"));

        // Get events from the target calendar using the full URL
        let events: Vec<CalendarEvent> = match target_sync_engine.client.get_events(&target_calendar.url, start_date, end_date).await {
            Ok(events) => events,
            Err(e) => {
                error!("Failed to retrieve events from target calendar: {}", e);
                println!("❌ Failed to retrieve events: {}", e);
                return Err(e.into());
            }
        };

        println!("\n📊 Event Summary");
        println!("================");
        println!("Total events found: {}", events.len());
        
        if events.is_empty() {
            println!("\nNo events found in the specified date range.");
            return Ok(());
        }

        // Count events by status and other properties
        let mut confirmed_events = 0;
        let mut tentative_events = 0;
        let mut cancelled_events = 0;
        let mut all_day_events = 0;
        let mut events_with_location = 0;
        let mut upcoming_events = 0;
        let mut past_events = 0;

        for event in &events {
            // Count by status
            if let Some(ref status) = event.status {
                match status.to_lowercase().as_str() {
                    "confirmed" => confirmed_events += 1,
                    "tentative" => tentative_events += 1,
                    "cancelled" => cancelled_events += 1,
                    _ => {}
                }
            }

            // Check if all-day (simple heuristic)
            if event.start.time() == chrono::NaiveTime::from_hms_opt(0, 0, 0).unwrap() &&
               event.end.time() == chrono::NaiveTime::from_hms_opt(23, 59, 59).unwrap_or(chrono::NaiveTime::from_hms_opt(0, 0, 0).unwrap()) {
                all_day_events += 1;
            }

            // Count events with locations
            if let Some(ref location) = event.location {
                if !location.is_empty() {
                    events_with_location += 1;
                }
            }

            // Count upcoming vs past events
            if event.end > now {
                upcoming_events += 1;
            } else {
                past_events += 1;
            }
        }

        println!("  Confirmed: {}", confirmed_events);
        println!("  Tentative: {}", tentative_events);
        println!("  Cancelled: {}", cancelled_events);
        println!("  All-day: {}", all_day_events);
        println!("  With location: {}", events_with_location);
        println!("  Upcoming: {}", upcoming_events);
        println!("  Past: {}", past_events);

        // Display detailed event information
        println!("\n📅 Event Details");
        println!("=================");

        // Sort events by start time
        let mut sorted_events = events.clone();
        sorted_events.sort_by(|a, b| a.start.cmp(&b.start));

        for (i, event) in sorted_events.iter().enumerate() {
            println!("\n{}. {}", i + 1, event.summary);
            
            // Format dates and times
            let start_formatted = event.start.format("%Y-%m-%d %H:%M");
            let end_formatted = event.end.format("%Y-%m-%d %H:%M");
            
            println!("   📅 {} to {}", start_formatted, end_formatted);
            
            // Event ID
            println!("   🆔 ID: {}", event.id);
            
            // Status
            let status_icon = if let Some(ref status) = event.status {
                match status.to_lowercase().as_str() {
                    "confirmed" => "✅",
                    "tentative" => "🔄",
                    "cancelled" => "❌",
                    _ => "❓",
                }
            } else {
                "❓"
            };
            
            let status_display = event.status.as_deref().unwrap_or("Unknown");
            println!("   📊 Status: {} {}", status_icon, status_display);
            
            // Location
            if let Some(ref location) = event.location {
                if !location.is_empty() {
                    println!("   📍 Location: {}", location);
                }
            }
            
            // Description (truncated if too long)
            if let Some(ref description) = event.description {
                if !description.is_empty() {
                    let truncated = if description.len() > 100 {
                        format!("{}...", &description[..97])
                    } else {
                        description.clone()
                    };
                    println!("   📝 Description: {}", truncated);
                }
            }
            
            // ETag for synchronization info
            if let Some(ref etag) = event.etag {
                println!("   🏷️  ETag: {}", etag);
            }
        }

        // Import analysis
        println!("\n🔍 Import Analysis");
        println!("==================");
        println!("This target calendar contains {} events.", events.len());
        
        if cli.import_info {
            println!("\nBased on the strict unidirectional import behavior:");
            println!("- These events would be checked against source events");
            println!("- Events not present in source would be deleted (if using strict_with_cleanup)");
            println!("- Events present in both would be updated if source is newer");
            println!("- New events from source would be added to this calendar");
            
            println!("\nRecommendations:");
            if events.len() > 100 {
                println!("- ⚠️  Large number of events - consider using strict behavior first");
            }
            if cancelled_events > 0 {
                println!("- 🗑️  {} cancelled events could be cleaned up", cancelled_events);
            }
            if past_events > events.len() / 2 {
                println!("- 📚 Many past events - consider cleanup if not needed");
            }
        }

        return Ok(());
    }

    // Create sync engine for other operations
    let mut sync_engine = SyncEngine::new(config.clone()).await?;

    if cli.list_events {
        // Check if we should list events from import target calendar
        if cli.import_info {
            // List events from import target calendar (similar to list_import_events but simplified)
            info!("Listing events from import target calendar");
            
            // Validate import configuration
            let import_config = match config.get_import_config() {
                Some(config) => config,
                None => {
                    error!("No import target configured. Please add [import] section to config.toml");
                    return Err(anyhow::anyhow!("Import configuration not found").into());
                }
            };

            // Override target calendar if specified via CLI
            let target_calendar_name = cli.nextcloud_calendar.as_ref()
                .unwrap_or(&import_config.target_calendar.name);

            println!("📅 Events from Import Target Calendar");
            println!("=====================================");
            println!("Target Server: {}", import_config.target_server.url);
            println!("Target Calendar: {}\n", target_calendar_name);

            // Create a temporary config for the target server
            let mut target_config = config.clone();
            target_config.server.url = import_config.target_server.url.clone();
            target_config.server.username = import_config.target_server.username.clone();
            target_config.server.password = import_config.target_server.password.clone();
            target_config.server.timeout = import_config.target_server.timeout;
            target_config.server.use_https = import_config.target_server.use_https;
            target_config.server.headers = import_config.target_server.headers.clone();
            target_config.calendar.name = target_calendar_name.clone();

            // Connect to target server
            let target_sync_engine = match SyncEngine::new(target_config).await {
                Ok(engine) => engine,
                Err(e) => {
                    error!("Failed to connect to target server: {}", e);
                    println!("❌ Failed to connect to target server: {}", e);
                    return Err(e.into());
                }
            };

            println!("✅ Successfully connected to target server!");

            // Discover calendars to find the target calendar URL
            let target_calendars = match target_sync_engine.client.discover_calendars().await {
                Ok(calendars) => calendars,
                Err(e) => {
                    error!("Failed to discover calendars on target server: {}", e);
                    println!("❌ Failed to discover calendars: {}", e);
                    return Err(e.into());
                }
            };

            // Find the target calendar
            let target_calendar = target_calendars.iter()
                .find(|c| c.name == *target_calendar_name || c.display_name.as_ref().map_or(false, |dn| dn == target_calendar_name));

            let target_calendar = match target_calendar {
                Some(calendar) => {
                    println!("✅ Found target calendar: {}", calendar.display_name.as_ref().unwrap_or(&calendar.name));
                    calendar
                }
                None => {
                    println!("❌ Target calendar '{}' not found on server", target_calendar_name);
                    println!("Available calendars:");
                    for calendar in &target_calendars {
                        println!("  - {}", calendar.display_name.as_ref().unwrap_or(&calendar.name));
                    }
                    return Err(anyhow::anyhow!("Target calendar not found").into());
                }
            };

            // Set date range for event listing (past 30 days to next 30 days)
            let now = Utc::now();
            let start_date = now - Duration::days(30);
            let end_date = now + Duration::days(30);

            println!("\nRetrieving events from {} to {}...", 
                    start_date.format("%Y-%m-%d"), 
                    end_date.format("%Y-%m-%d"));

            // Get events from the target calendar using the full URL
            let events: Vec<CalendarEvent> = match target_sync_engine.client.get_events(&target_calendar.url, start_date, end_date).await {
                Ok(events) => events,
                Err(e) => {
                    error!("Failed to retrieve events from target calendar: {}", e);
                    println!("❌ Failed to retrieve events: {}", e);
                    return Err(e.into());
                }
            };

            println!("Found {} events:\n", events.len());
            
            // Display events in a simple format similar to the original list_events
            for event in events {
                let start_tz = event.start_tzid.as_deref().unwrap_or("UTC");
                let end_tz = event.end_tzid.as_deref().unwrap_or("UTC");
                println!("  - {} ({} {} to {} {})", 
                    event.summary, 
                    event.start.format("%Y-%m-%d %H:%M"),
                    start_tz,
                    event.end.format("%Y-%m-%d %H:%M"),
                    end_tz
                );
            }
            
            return Ok(());
        }

        // Original behavior: List events from source calendar and exit
        info!("Listing events from calendar: {}", config.calendar.name);
        
        // Use the specific approach if provided
        if let Some(ref approach) = cli.approach {
            info!("Using specific approach: {}", approach);
            
            // Use the provided calendar URL if available, otherwise discover calendars
            let calendar_url = if let Some(ref url) = cli.calendar_url {
                url.clone()
            } else {
                let calendars = sync_engine.client.discover_calendars().await?;
                if let Some(calendar) = calendars.iter().find(|c| c.name == config.calendar.name || c.display_name.as_ref().map_or(false, |n| n == &config.calendar.name)) {
                    calendar.url.clone()
                } else {
                    warn!("Calendar '{}' not found", config.calendar.name);
                    return Ok(());
                }
            };
            
            let now = Utc::now();
            let start_date = now - Duration::days(30);
            let end_date = now + Duration::days(30);
            
            match sync_engine.client.get_events_with_approach(&calendar_url, start_date, end_date, Some(approach.clone())).await {
                Ok(events) => {
                    println!("Found {} events using approach {}:", events.len(), approach);
                    for event in events {
                        let start_tz = event.start_tzid.as_deref().unwrap_or("UTC");
                        let end_tz = event.end_tzid.as_deref().unwrap_or("UTC");
                        println!("  - {} ({} {} to {} {})", 
                            event.summary, 
                            event.start.format("%Y-%m-%d %H:%M"),
                            start_tz,
                            event.end.format("%Y-%m-%d %H:%M"),
                            end_tz
                        );
                    }
                }
                Err(e) => {
                    error!("Failed to get events with approach {}: {}", approach, e);
                }
            }
            return Ok(());
        }
        
        // Perform a sync to get events
        let sync_result = sync_engine.sync_full().await?;
        info!("Sync completed: {} events processed", sync_result.events_processed);
        
        // Get and display events
        let events = sync_engine.get_local_events();
        println!("Found {} events:", events.len());
        
        for event in events {
            let start_tz = event.start_tzid.as_deref().unwrap_or("UTC");
            let end_tz = event.end_tzid.as_deref().unwrap_or("UTC");
            println!("  - {} ({} {} to {} {})", 
                event.summary, 
                event.start.format("%Y-%m-%d %H:%M"),
                start_tz,
                event.end.format("%Y-%m-%d %H:%M"),
                end_tz
            );
        }
        
        return Ok(());
    }

    if cli.once || cli.full_resync {
        // Perform one-time sync
        if cli.full_resync {
            info!("Performing full resynchronization");
            let result = sync_engine.force_full_resync().await?;
            info!("Full resync completed: {} events processed", result.events_processed);
        } else {
            info!("Performing one-time synchronization");
            let result = sync_engine.sync_incremental().await?;
            info!("Sync completed: {} events processed", result.events_processed);
        }
    } else {
        // Start continuous synchronization
        info!("Starting continuous synchronization");
        
        if config.sync.sync_on_startup {
            info!("Performing initial sync");
            match sync_engine.sync_incremental().await {
                Ok(result) => {
                    info!("Initial sync completed: {} events processed", result.events_processed);
                }
                Err(e) => {
                    warn!("Initial sync failed: {}", e);
                }
            }
        }

        // Start auto-sync loop
        sync_engine.start_auto_sync().await?;
    }

    Ok(())
}