use chrono::{DateTime, Utc};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;

/// Represents a calendar event with all its properties
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub struct CalendarEvent {
    /// Unique identifier for the event (UID field in iCal)
    pub uid: String,
    
    /// Summary/title of the event
    pub summary: Option<String>,
    
    /// Detailed description of the event
    pub description: Option<String>,
    
    /// Start date and time of the event
    pub start: DateTime<Utc>,
    
    /// End date and time of the event
    pub end: Option<DateTime<Utc>>,
    
    /// Location where the event takes place
    pub location: Option<String>,
    
    /// Event status (TENTATIVE, CONFIRMED, CANCELLED)
    pub status: EventStatus,
    
    /// Event classification (PUBLIC, PRIVATE, CONFIDENTIAL)
    pub class: EventClass,
    
    /// Event priority (0-9, where 0 is undefined, 1 is highest, 9 is lowest)
    pub priority: Option<u8>,
    
    /// Organizer of the event
    pub organizer: Option<String>,
    
    /// List of attendees
    pub attendees: Vec<String>,
    
    /// Categories/tags for the event
    pub categories: Vec<String>,
    
    /// Date and time when the event was created
    pub created: Option<DateTime<Utc>>,
    
    /// Date and time when the event was last modified
    pub last_modified: Option<DateTime<Utc>>,
    
    /// Recurrence rule (RRULE)
    pub recurrence_rule: Option<String>,
    
    /// All-day event flag
    pub all_day: bool,
    
    /// Reminders/alarms for this event
    pub reminders: Vec<EventReminder>,
    
    /// ETag from CalDAV server for conflict detection
    pub etag: Option<String>,
    
    /// URL/href of this event on the CalDAV server
    pub href: Option<String>,
    
    /// Calendar path this event belongs to
    pub calendar_path: Option<String>,
}

/// Event status enumeration
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub enum EventStatus {
    Tentative,
    Confirmed,
    Cancelled,
}

impl Default for EventStatus {
    fn default() -> Self {
        EventStatus::Confirmed
    }
}

/// Event classification enumeration
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub enum EventClass {
    Public,
    Private,
    Confidential,
}

impl Default for EventClass {
    fn default() -> Self {
        EventClass::Public
    }
}

/// Event reminder/alarm information
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub struct EventReminder {
    /// How long before the event to trigger the reminder (in minutes)
    pub minutes_before: i32,
    
    /// Type of reminder action
    pub action: ReminderAction,
    
    /// Optional description for the reminder
    pub description: Option<String>,
}

/// Reminder action types
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub enum ReminderAction {
    Display,
    Email,
    Audio,
}

/// CalDAV client for fetching and parsing calendar events
pub struct CalDAVClient {
    config: crate::config::CalDAVConfig,
    http_client: reqwest::Client,
}

impl CalDAVClient {
    /// Create a new CalDAV client with the given configuration
    pub fn new(config: crate::config::CalDAVConfig) -> Self {
        Self {
            config,
            http_client: reqwest::Client::new(),
        }
    }

    /// Fetch calendar events from the CalDAV server
    /// 
    /// This method performs a REPORT request to get calendar data and parses
    /// the returned iCalendar format into CalendarEvent structs.
    pub async fn fetch_events(&self, calendar_path: &str) -> Result<Vec<CalendarEvent>, CalDAVError> {
        // CalDAV REPORT request to get calendar events
        let report_body = r#"<?xml version="1.0" encoding="utf-8" ?>
<c:calendar-query xmlns:d="DAV:" xmlns:c="urn:ietf:params:xml:ns:caldav">
    <d:prop>
        <d:getetag/>
        <c:calendar-data/>
    </d:prop>
    <c:filter>
        <c:comp-filter name="VCALENDAR">
            <c:comp-filter name="VEVENT"/>
        </c:comp-filter>
    </c:filter>
</c:calendar-query>"#;

        let url = if calendar_path.starts_with("http") {
            calendar_path.to_string()
        } else {
            // Extract the base URL (scheme + host + port) from server_url
            let server_url = &self.config.server_url;
            // Find the first '/' after "https://" or "http://"
            let scheme_end = if server_url.starts_with("https://") { 8 } else { 7 };
            if let Some(path_start) = server_url[scheme_end..].find('/') {
                let base_url = &server_url[..scheme_end + path_start];
                format!("{}{}", base_url, calendar_path)
            } else {
                // No path in server_url, so just append the calendar_path
                format!("{}{}", server_url.trim_end_matches('/'), calendar_path)
            }
        };

        let basic_auth = self.config.get_basic_auth();
        println!("🔑 REPORT Basic Auth: Basic {}", basic_auth);
        println!("🌐 REPORT URL: {}", url);
        
        let response = self.http_client
            .request(reqwest::Method::from_bytes(b"REPORT").unwrap(), &url)
            .header("Authorization", format!("Basic {}", basic_auth))
            .header("Content-Type", "application/xml")
            .header("Depth", "1")
            .header("User-Agent", "calendar-app/0.1.0")
            .body(report_body)
            .send()
            .await
            .map_err(CalDAVError::RequestError)?;

        if !response.status().is_success() && response.status().as_u16() != 207 {
            return Err(CalDAVError::ServerError(response.status().as_u16()));
        }

        let body = response.text().await.map_err(CalDAVError::RequestError)?;
        self.parse_calendar_response(&body, calendar_path)
    }

    /// Parse CalDAV XML response containing calendar data
    fn parse_calendar_response(&self, xml_response: &str, calendar_path: &str) -> Result<Vec<CalendarEvent>, CalDAVError> {
        let mut events = Vec::new();
        
        // Extract calendar data from XML response
        // This is a simplified parser - in production, you'd want a proper XML parser
        let calendar_data_sections = self.extract_calendar_data(xml_response);
        
        for calendar_data in calendar_data_sections {
            if let Ok(parsed_events) = self.parse_ical_data(&calendar_data.data) {
                for mut event in parsed_events {
                    event.etag = calendar_data.etag.clone();
                    event.href = calendar_data.href.clone();
                    event.calendar_path = Some(calendar_path.to_string());
                    events.push(event);
                }
            }
        }

        Ok(events)
    }

    /// Fetch a single calendar event by UID from the CalDAV server
    pub async fn fetch_event_by_uid(&self, calendar_path: &str, uid: &str) -> Result<Option<CalendarEvent>, CalDAVError> {
        // First fetch all events and find the one with matching UID
        let events = self.fetch_events(calendar_path).await?;
        
        // Find event with matching UID
        let event = events.into_iter().find(|e| e.uid == uid);
        
        Ok(event)
    }

    /// Extract calendar data sections from CalDAV XML response
    fn extract_calendar_data(&self, xml_response: &str) -> Vec<CalendarDataSection> {
        let mut sections = Vec::new();
        
        // Simple regex-based extraction (in production, use a proper XML parser)
        // Look for <d:response> blocks containing calendar data
        for response_block in xml_response.split("<d:response>").skip(1) {
            if let Some(end_pos) = response_block.find("</d:response>") {
                let response_content = &response_block[..end_pos];
                
                let href = self.extract_xml_content(response_content, "href").unwrap_or_default();
                let etag = self.extract_xml_content(response_content, "getetag").unwrap_or_default();
                
                if let Some(calendar_data) = self.extract_xml_content(response_content, "cal:calendar-data") {
                    sections.push(CalendarDataSection {
                        href: if href.is_empty() { None } else { Some(href) },
                        etag: if etag.is_empty() { None } else { Some(etag) },
                        data: calendar_data,
                    });
                }
            }
        }
        
        sections
    }

    /// Extract content from XML tags (simple implementation)
    fn extract_xml_content(&self, xml: &str, tag: &str) -> Option<String> {
        // Handle both with and without namespace prefixes
        let patterns = [
            format!("(?s)<{}>(.*?)</{}>", tag, tag),                    // <tag>content</tag>
            format!("(?s)<{}>(.*?)</.*:{}>", tag, tag.split(':').last().unwrap_or(tag)),  // <tag>content</ns:tag>
            format!("(?s)<.*:{}>(.*?)</{}>", tag.split(':').last().unwrap_or(tag), tag), // <ns:tag>content</tag>
            format!("(?s)<.*:{}>(.*?)</.*:{}>", tag.split(':').last().unwrap_or(tag), tag.split(':').last().unwrap_or(tag)), // <ns:tag>content</ns:tag>
            format!("(?s)<{}[^>]*>(.*?)</{}>", tag, tag),               // <tag attr>content</tag>
            format!("(?s)<{}[^>]*>(.*?)</.*:{}>", tag, tag.split(':').last().unwrap_or(tag)),
        ];
        
        for pattern in &patterns {
            if let Ok(re) = regex::Regex::new(pattern) {
                if let Some(captures) = re.captures(xml) {
                    if let Some(content) = captures.get(1) {
                        return Some(content.as_str().trim().to_string());
                    }
                }
            }
        }
        
        None
    }

    /// Parse iCalendar data into CalendarEvent structs
    fn parse_ical_data(&self, ical_data: &str) -> Result<Vec<CalendarEvent>, CalDAVError> {
        let mut events = Vec::new();
        
        // Parse the iCal data using the ical crate
        let reader = ical::IcalParser::new(ical_data.as_bytes());
        
        for calendar in reader {
            let calendar = calendar.map_err(|e| CalDAVError::ParseError(e.to_string()))?;
            
            for event in calendar.events {
                if let Ok(calendar_event) = self.parse_ical_event(event) {
                    events.push(calendar_event);
                }
            }
        }
        
        Ok(events)
    }

    /// Parse a single iCal event into a CalendarEvent struct
    fn parse_ical_event(&self, event: ical::parser::ical::component::IcalEvent) -> Result<CalendarEvent, CalDAVError> {
        let mut properties: HashMap<String, String> = HashMap::new();
        
        // Extract all properties from the event
        for property in &event.properties {
            properties.insert(property.name.to_uppercase(), property.value.clone().unwrap_or_default());
        }

        // Required UID field
        let uid = properties.get("UID")
            .ok_or_else(|| CalDAVError::ParseError("Missing UID field".to_string()))?
            .clone();

        // Parse start time (required)
        let start = properties.get("DTSTART")
            .ok_or_else(|| CalDAVError::ParseError("Missing DTSTART field".to_string()))?;
        let start = self.parse_datetime(start, properties.get("DTSTART"))?;

        // Parse end time (optional - use start time if not present)
        let end = if let Some(dtend) = properties.get("DTEND") {
            Some(self.parse_datetime(dtend, properties.get("DTEND"))?)
        } else if let Some(_duration) = properties.get("DURATION") {
            // TODO: Parse duration and add to start time
            Some(start)
        } else {
            None
        };

        // Determine if it's an all-day event
        let all_day = properties.get("DTSTART")
            .map(|s| !s.contains("T"))
            .unwrap_or(false);

        // Parse status
        let status = properties.get("STATUS")
            .map(|s| match s.to_uppercase().as_str() {
                "TENTATIVE" => EventStatus::Tentative,
                "CANCELLED" => EventStatus::Cancelled,
                _ => EventStatus::Confirmed,
            })
            .unwrap_or_default();

        // Parse classification
        let class = properties.get("CLASS")
            .map(|s| match s.to_uppercase().as_str() {
                "PRIVATE" => EventClass::Private,
                "CONFIDENTIAL" => EventClass::Confidential,
                _ => EventClass::Public,
            })
            .unwrap_or_default();

        // Parse priority
        let priority = properties.get("PRIORITY")
            .and_then(|s| s.parse::<u8>().ok())
            .filter(|&p| p <= 9);

        // Parse categories
        let categories = properties.get("CATEGORIES")
            .map(|s| s.split(',').map(|c| c.trim().to_string()).collect())
            .unwrap_or_default();

        // Parse dates
        let created = properties.get("CREATED")
            .and_then(|s| self.parse_datetime(s, None).ok());
        
        let last_modified = properties.get("LAST-MODIFIED")
            .and_then(|s| self.parse_datetime(s, None).ok());

        Ok(CalendarEvent {
            uid,
            summary: properties.get("SUMMARY").cloned(),
            description: properties.get("DESCRIPTION").cloned(),
            start,
            end,
            location: properties.get("LOCATION").cloned(),
            status,
            class,
            priority,
            organizer: properties.get("ORGANIZER").cloned(),
            attendees: Vec::new(), // TODO: Parse attendees
            categories,
            created,
            last_modified,
            recurrence_rule: properties.get("RRULE").cloned(),
            all_day,
            reminders: self.parse_alarms(&event)?,
            etag: None, // Set by caller
            href: None, // Set by caller
            calendar_path: None, // Set by caller
        })
    }

    /// Parse VALARM components from an iCal event
    fn parse_alarms(&self, event: &ical::parser::ical::component::IcalEvent) -> Result<Vec<EventReminder>, CalDAVError> {
        let mut reminders = Vec::new();
        
        for alarm in &event.alarms {
            if let Ok(reminder) = self.parse_single_alarm(alarm) {
                reminders.push(reminder);
            }
        }
        
        Ok(reminders)
    }

    /// Parse a single VALARM component into an EventReminder
    fn parse_single_alarm(&self, alarm: &ical::parser::ical::component::IcalAlarm) -> Result<EventReminder, CalDAVError> {
        let mut properties: HashMap<String, String> = HashMap::new();
        
        // Extract all properties from the alarm
        for property in &alarm.properties {
            properties.insert(property.name.to_uppercase(), property.value.clone().unwrap_or_default());
        }
        
        // Parse ACTION (required)
        let action = match properties.get("ACTION").map(|s| s.to_uppercase()) {
            Some(ref action_str) if action_str == "DISPLAY" => ReminderAction::Display,
            Some(ref action_str) if action_str == "EMAIL" => ReminderAction::Email,
            Some(ref action_str) if action_str == "AUDIO" => ReminderAction::Audio,
            _ => ReminderAction::Display, // Default
        };
        
        // Parse TRIGGER (required)
        let minutes_before = if let Some(trigger) = properties.get("TRIGGER") {
            self.parse_trigger_duration(trigger).unwrap_or(15) // Default 15 minutes
        } else {
            15 // Default 15 minutes
        };
        
        // Get description
        let description = properties.get("DESCRIPTION").cloned();
        
        Ok(EventReminder {
            minutes_before,
            action,
            description,
        })
    }

    /// Parse a TRIGGER duration string into minutes before event
    fn parse_trigger_duration(&self, trigger: &str) -> Option<i32> {
        // Basic parsing of ISO 8601 duration or relative time
        // Examples: "-PT15M" (15 minutes before), "-P1D" (1 day before)
        
        if trigger.starts_with("-PT") && trigger.ends_with("M") {
            // Parse "-PT15M" format (minutes)
            let minutes_str = &trigger[3..trigger.len()-1];
            minutes_str.parse::<i32>().ok()
        } else if trigger.starts_with("-PT") && trigger.ends_with("H") {
            // Parse "-PT1H" format (hours)
            let hours_str = &trigger[3..trigger.len()-1];
            hours_str.parse::<i32>().ok().map(|h| h * 60)
        } else if trigger.starts_with("-P") && trigger.ends_with("D") {
            // Parse "-P1D" format (days)
            let days_str = &trigger[2..trigger.len()-1];
            days_str.parse::<i32>().ok().map(|d| d * 24 * 60)
        } else {
            // Try to parse as raw minutes
            trigger.parse::<i32>().ok().map(|m| m.abs())
        }
    }

    /// Discover available calendar collections on the server
    pub async fn discover_calendars(&self) -> Result<Vec<String>, CalDAVError> {
        // First, try to discover user calendars if we have a calendar path in config
        if let Some(calendar_path) = &self.config.calendar_path {
            println!("Using configured calendar path: {}", calendar_path);
            return Ok(vec![calendar_path.clone()]);
        }
        
        println!("No calendar path configured, discovering calendars...");

        // Try different common CalDAV discovery paths
        // Note: paths should be relative to the server URL base
        let user_calendar_path = format!("/calendars/{}/", self.config.username);
        
        let discovery_paths = vec![
            "/calendars/",
            user_calendar_path.as_str(),
        ];

        let mut all_calendars = Vec::new();

        for path in discovery_paths {
            println!("Trying discovery path: {}", path);
            if let Ok(calendars) = self.discover_calendars_at_path(&path).await {
                println!("Found {} calendar(s) at {}", calendars.len(), path);
                all_calendars.extend(calendars);
            }
        }

        // Remove duplicates
        all_calendars.sort();
        all_calendars.dedup();

        Ok(all_calendars)
    }

    /// Discover calendars at a specific path
    async fn discover_calendars_at_path(&self, path: &str) -> Result<Vec<String>, CalDAVError> {
        let propfind_body = r#"<?xml version="1.0" encoding="utf-8" ?>
<d:propfind xmlns:d="DAV:" xmlns:c="urn:ietf:params:xml:ns:caldav">
    <d:prop>
        <d:resourcetype />
        <d:displayname />
        <c:supported-calendar-component-set />
    </d:prop>
</d:propfind>"#;

        let url = format!("{}{}", self.config.server_url.trim_end_matches('/'), path);

        let response = self.http_client
            .request(reqwest::Method::from_bytes(b"PROPFIND").unwrap(), &url)
            .header("Authorization", format!("Basic {}", self.config.get_basic_auth()))
            .header("Content-Type", "application/xml")
            .header("Depth", "2") // Deeper search to find actual calendars
            .header("User-Agent", "calendar-app/0.1.0")
            .body(propfind_body)
            .send()
            .await
            .map_err(CalDAVError::RequestError)?;

        if response.status().as_u16() != 207 {
            println!("❌ Discovery PROPFIND failed for {}: HTTP {}", path, response.status().as_u16());
            return Err(CalDAVError::ServerError(response.status().as_u16()));
        }

        let body = response.text().await.map_err(CalDAVError::RequestError)?;
        println!("Discovery response for {}: {}", path, body);
        
        let mut calendar_paths = Vec::new();
        
        // Extract calendar collection URLs from the response
        for response_block in body.split("<d:response>").skip(1) {
            if let Some(end_pos) = response_block.find("</d:response>") {
                let response_content = &response_block[..end_pos];
                
                // Extract href first
                if let Some(href) = self.extract_xml_content(response_content, "href") {
                    println!("🔍 Checking resource: {}", href);
                    
                    // Check if this is a calendar collection by looking for supported-calendar-component-set
                    // This indicates it's an actual calendar that can contain events
                    let has_supported_components = response_content.contains("supported-calendar-component-set") &&
                                                  (response_content.contains("VEVENT") || response_content.contains("VTODO"));
                    let has_calendar_resourcetype = response_content.contains("<cal:calendar") || response_content.contains("<c:calendar");
                    
                    let is_calendar = has_supported_components || has_calendar_resourcetype;
                    
                    // Also check resourcetype for collection
                    let has_collection = response_content.contains("<d:collection") || response_content.contains("<collection");
                    
                    if is_calendar && has_collection {
                        // Exclude system directories like inbox, outbox, and root calendar directories
                        if !href.contains("/inbox/") && !href.contains("/outbox/") && 
                           !href.ends_with("/calendars/") && href.ends_with('/') {
                            println!("📅 Found calendar collection: {}", href);
                            calendar_paths.push(href);
                        } else {
                            println!("❌ Skipping system/root directory: {}", href);
                        }
                    } else {
                        println!("ℹ️  Not a calendar collection: {} (is_calendar: {}, has_collection: {})", 
                               href, is_calendar, has_collection);
                    }
                }
            }
        }
        
        Ok(calendar_paths)
    }

    /// Parse iCal datetime format
    fn parse_datetime(&self, datetime_str: &str, _original_property: Option<&String>) -> Result<DateTime<Utc>, CalDAVError> {
        use chrono::TimeZone;
        
        // Handle different iCal datetime formats
        let cleaned = datetime_str.replace("TZID=", "").trim().to_string();
        
        // Try different parsing formats
        let formats = [
            "%Y%m%dT%H%M%SZ",        // UTC format: 20231225T120000Z
            "%Y%m%dT%H%M%S",         // Local format: 20231225T120000
            "%Y%m%d",                // Date only: 20231225
        ];
        
        for format in &formats {
            if let Ok(dt) = chrono::NaiveDateTime::parse_from_str(&cleaned, format) {
                return Ok(Utc.from_utc_datetime(&dt));
            }
            if let Ok(date) = chrono::NaiveDate::parse_from_str(&cleaned, format) {
                return Ok(Utc.from_utc_datetime(&date.and_hms_opt(0, 0, 0).unwrap()));
            }
        }
        
        Err(CalDAVError::ParseError(format!("Unable to parse datetime: {}", datetime_str)))
    }

    /// Create a new calendar on the CalDAV server using MKCALENDAR
    pub async fn create_calendar(&self, name: &str, description: Option<&str>, color: Option<&str>) -> Result<(), CalDAVError> {
        // Sanitize calendar name for URL path
        let calendar_id = name
            .chars()
            .map(|c| if c.is_alphanumeric() { c } else { '-' })
            .collect::<String>()
            .to_lowercase();
        
        let calendar_path = format!("/calendars/{}/{}/", self.config.username, calendar_id);
        let full_url = format!("{}{}", self.config.server_url.trim_end_matches('/'), calendar_path);
        
        // Build color property if provided
        let color_property = if let Some(color) = color {
            format!(r#"<ic:calendar-color xmlns:ic="http://apple.com/ns/ical/">{}</ic:calendar-color>"#, color)
        } else {
            String::new()
        };
        
        let description_property = if let Some(desc) = description {
            format!(r#"<c:calendar-description xmlns:c="urn:ietf:params:xml:ns:caldav">{}</c:calendar-description>"#, desc)
        } else {
            String::new()
        };
        
        // Create the MKCALENDAR request body
        let mkcalendar_body = format!(
            r#"<?xml version="1.0" encoding="utf-8" ?>
<c:mkcalendar xmlns:d="DAV:" xmlns:c="urn:ietf:params:xml:ns:caldav" xmlns:ic="http://apple.com/ns/ical/">
    <d:set>
        <d:prop>
            <d:displayname>{}</d:displayname>
            <c:supported-calendar-component-set>
                <c:comp name="VEVENT"/>
            </c:supported-calendar-component-set>
            {}
            {}
        </d:prop>
    </d:set>
</c:mkcalendar>"#,
            name, color_property, description_property
        );
        
        println!("Creating calendar at: {}", full_url);
        println!("MKCALENDAR body: {}", mkcalendar_body);
        
        let response = self.http_client
            .request(reqwest::Method::from_bytes(b"MKCALENDAR").unwrap(), &full_url)
            .header("Content-Type", "application/xml; charset=utf-8")
            .header("Authorization", format!("Basic {}", self.config.get_basic_auth()))
            .body(mkcalendar_body)
            .send()
            .await
            .map_err(|e| CalDAVError::ParseError(e.to_string()))?;

        println!("Calendar creation response status: {}", response.status());
        
        if response.status().is_success() {
            println!("✅ Calendar created successfully at {}", calendar_path);
            Ok(())
        } else {
            let status = response.status();
            let error_body = response.text().await.unwrap_or_default();
            println!("❌ Calendar creation failed: {} - {}", status, error_body);
            Err(CalDAVError::ServerError(status.as_u16()))
        }
    }
}

/// Helper struct for extracting calendar data from XML responses
#[derive(Debug)]
struct CalendarDataSection {
    pub href: Option<String>,
    pub etag: Option<String>,
    pub data: String,
}

/// CalDAV-specific error types
#[derive(Debug, thiserror::Error)]
pub enum CalDAVError {
    #[error("HTTP request failed: {0}")]
    RequestError(#[from] reqwest::Error),
    
    #[error("CalDAV server returned error: {0}")]
    ServerError(u16),
    
    #[error("Failed to parse calendar data: {0}")]
    ParseError(String),
    
    #[error("Configuration error: {0}")]
    ConfigError(String),
}

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

    /// Integration test that fetches real calendar events from the Baikal server
    /// 
    /// This test requires a valid .env file and a calendar with some events
    #[tokio::test]
    async fn test_fetch_calendar_events() {
        let config = CalDAVConfig::from_env()
            .expect("Failed to load CalDAV config from environment");
        
        let client = CalDAVClient::new(config);
        
        // First discover available calendars using PROPFIND
        println!("Discovering calendars...");
        let discovery_result = client.discover_calendars().await;
        
        match discovery_result {
            Ok(calendar_paths) => {
                println!("Found {} calendar collection(s)", calendar_paths.len());
                
                if calendar_paths.is_empty() {
                    println!("No calendars found - this might be normal for a new server");
                    return;
                }
                
                // Try the first available calendar
                let calendar_path = &calendar_paths[0];
                println!("Trying to fetch events from: {}", calendar_path);
                
                match client.fetch_events(calendar_path).await {
                    Ok(events) => {
                        println!("Successfully fetched {} calendar events", events.len());
                        
                        for (i, event) in events.iter().take(3).enumerate() {
                            println!("\n--- Event {} ---", i + 1);
                            println!("UID: {}", event.uid);
                            println!("Summary: {:?}", event.summary);
                            println!("Start: {}", event.start);
                            println!("End: {:?}", event.end);
                            println!("All Day: {}", event.all_day);
                            println!("Status: {:?}", event.status);
                            println!("Location: {:?}", event.location);
                            println!("Description: {:?}", event.description);
                            println!("ETag: {:?}", event.etag);
                            println!("HREF: {:?}", event.href);
                        }
                        
                        // Validate that events have required fields
                        for event in &events {
                            assert!(!event.uid.is_empty(), "Event UID should not be empty");
                            // All events should have a start time
                            assert!(event.start > DateTime::from_timestamp(0, 0).unwrap(), "Event should have valid start time");
                        }
                        
                        println!("\n✓ Calendar event fetching test passed!");
                    }
                    Err(e) => {
                        println!("Error fetching events from {}: {:?}", calendar_path, e);
                        println!("This might be normal if the calendar is empty");
                    }
                }
            }
            Err(e) => {
                println!("Error discovering calendars: {:?}", e);
                println!("This might be normal if no calendars are set up yet");
            }
        }
    }

}

/// Test parsing a sample iCal event
    #[test]
    fn test_parse_ical_event() {
        let sample_ical = r#"BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Test//Test//EN
BEGIN:VEVENT
UID:test-event-123@example.com
DTSTART:20231225T120000Z
DTEND:20231225T130000Z
SUMMARY:Test Event
DESCRIPTION:This is a test event
LOCATION:Test Location
STATUS:CONFIRMED
CLASS:PUBLIC
PRIORITY:5
CREATED:20231220T100000Z
LAST-MODIFIED:20231221T150000Z
CATEGORIES:work,important
END:VEVENT
END:VCALENDAR"#;

        let config = CalDAVConfig {
            server_url: "https://example.com".to_string(),
            username: "test".to_string(),
            password: "test".to_string(),
            calendar_path: None,
            tasks_path: None,
        };
        
        let client = CalDAVClient::new(config);
        let events = client.parse_ical_data(sample_ical)
            .expect("Should be able to parse sample iCal data");

        assert_eq!(events.len(), 1);
        
        let event = &events[0];
        assert_eq!(event.uid, "test-event-123@example.com");
        assert_eq!(event.summary, Some("Test Event".to_string()));
        assert_eq!(event.description, Some("This is a test event".to_string()));
        assert_eq!(event.location, Some("Test Location".to_string()));
        assert_eq!(event.status, EventStatus::Confirmed);
        assert_eq!(event.class, EventClass::Public);
        assert_eq!(event.priority, Some(5));
        assert_eq!(event.categories, vec!["work", "important"]);
        assert!(!event.all_day);
        
        println!("✓ iCal parsing test passed!");
    }

    /// Test datetime parsing
    #[test]
    fn test_datetime_parsing() {
        let config = CalDAVConfig {
            server_url: "https://example.com".to_string(),
            username: "test".to_string(),
            password: "test".to_string(),
            calendar_path: None,
            tasks_path: None,
        };
        
        let client = CalDAVClient::new(config);
        
        // Test UTC format
        let dt1 = client.parse_datetime("20231225T120000Z", None)
            .expect("Should parse UTC datetime");
        println!("Parsed UTC datetime: {}", dt1);
        
        // Test date-only format (should be treated as all-day)
        let dt2 = client.parse_datetime("20231225", None)
            .expect("Should parse date-only");
        println!("Parsed date-only: {}", dt2);
        
        // Test local format
        let dt3 = client.parse_datetime("20231225T120000", None)
            .expect("Should parse local datetime");
        println!("Parsed local datetime: {}", dt3);
        
        println!("✓ Datetime parsing test passed!");
    }

    /// Test event status parsing
    #[test]
    fn test_event_enums() {
        // Test status parsing
        assert_eq!(EventStatus::default(), EventStatus::Confirmed);
        
        // Test class parsing  
        assert_eq!(EventClass::default(), EventClass::Public);
        
        println!("✓ Event enum tests passed!");
    }