use cm_dashboard_shared::{Metric, Status};
use ratatui::{
    layout::{Constraint, Direction, Layout, Rect},
    widgets::Paragraph,
    Frame,
};
use std::collections::HashMap;
use tracing::debug;

use super::Widget;
use crate::ui::theme::{Components, StatusIcons, Theme, Typography};
use ratatui::style::Style;

/// Services widget displaying hierarchical systemd service statuses
#[derive(Clone)]
pub struct ServicesWidget {
    /// Parent services (nginx, docker, etc.)
    parent_services: HashMap<String, ServiceInfo>,
    /// Sub-services grouped by parent (nginx -> [gitea, mariehall, ...], docker -> [container1, ...])
    sub_services: HashMap<String, Vec<(String, ServiceInfo)>>,
    /// Aggregated status
    status: Status,
    /// Last update indicator
    has_data: bool,
    /// Currently selected service index (for navigation cursor)
    selected_index: usize,
}

#[derive(Clone)]
struct ServiceInfo {
    status: String,
    memory_mb: Option<f32>,
    disk_gb: Option<f32>,
    latency_ms: Option<f32>,
    widget_status: Status,
}

impl ServicesWidget {
    pub fn new() -> Self {
        Self {
            parent_services: HashMap::new(),
            sub_services: HashMap::new(),
            status: Status::Unknown,
            has_data: false,
            selected_index: 0,
        }
    }

    /// Extract service name and determine if it's a parent or sub-service
    fn extract_service_info(metric_name: &str) -> Option<(String, Option<String>)> {
        if metric_name.starts_with("service_") {
            if let Some(end_pos) = metric_name
                .rfind("_status")
                .or_else(|| metric_name.rfind("_memory_mb"))
                .or_else(|| metric_name.rfind("_disk_gb"))
                .or_else(|| metric_name.rfind("_latency_ms"))
            {
                let service_part = &metric_name[8..end_pos]; // Remove "service_" prefix

                // Check for sub-services patterns
                if service_part.starts_with("nginx_") {
                    // nginx sub-services: service_nginx_gitea_latency_ms -> ("nginx", "gitea")
                    let sub_service = service_part.strip_prefix("nginx_").unwrap_or(service_part);
                    return Some(("nginx".to_string(), Some(sub_service.to_string())));
                } else if service_part.starts_with("docker_") {
                    // docker sub-services: service_docker_container1_status -> ("docker", "container1")
                    let sub_service = service_part.strip_prefix("docker_").unwrap_or(service_part);
                    return Some(("docker".to_string(), Some(sub_service.to_string())));
                } else {
                    // Regular parent service: service_nginx_status -> ("nginx", None)
                    return Some((service_part.to_string(), None));
                }
            }
        }
        None
    }

    /// Format disk size with appropriate units (kB/MB/GB)
    fn format_disk_size(size_gb: f32) -> String {
        let size_mb = size_gb * 1024.0; // Convert GB to MB

        if size_mb >= 1024.0 {
            // Show as GB
            format!("{:.1}GB", size_gb)
        } else if size_mb >= 1.0 {
            // Show as MB
            format!("{:.0}MB", size_mb)
        } else if size_mb >= 0.001 {
            // Convert to kB
            let size_kb = size_mb * 1024.0;
            format!("{:.0}kB", size_kb)
        } else {
            // Show very small sizes as bytes
            let size_bytes = size_mb * 1024.0 * 1024.0;
            format!("{:.0}B", size_bytes)
        }
    }

    /// Format parent service line - returns text without icon for span formatting
    fn format_parent_service_line(&self, name: &str, info: &ServiceInfo) -> String {
        let memory_str = info
            .memory_mb
            .map_or("0M".to_string(), |m| format!("{:.0}M", m));
        let disk_str = info
            .disk_gb
            .map_or("0".to_string(), |d| Self::format_disk_size(d));

        // Truncate long service names to fit layout (account for icon space)
        let short_name = if name.len() > 22 {
            format!("{}...", &name[..19])
        } else {
            name.to_string()
        };

        // Parent services always show actual systemctl status
        let status_str = match info.widget_status {
            Status::Pending => "pending".to_string(),
            _ => info.status.clone(), // Use actual status from agent (active/inactive/failed)
        };

        format!(
            "{:<23} {:<10} {:<8} {:<8}",
            short_name, status_str, memory_str, disk_str
        )
    }



    /// Create spans for sub-service with icon next to name
    fn create_sub_service_spans(
        &self,
        name: &str,
        info: &ServiceInfo,
        is_last: bool,
    ) -> Vec<ratatui::text::Span<'static>> {
        // Truncate long sub-service names to fit layout (accounting for indentation)
        let short_name = if name.len() > 18 {
            format!("{}...", &name[..15])
        } else {
            name.to_string()
        };

        // Get status icon and text
        let icon = StatusIcons::get_icon(info.widget_status);
        let status_color = match info.widget_status {
            Status::Ok => Theme::success(),
            Status::Inactive => Theme::muted_text(),
            Status::Pending => Theme::highlight(),
            Status::Warning => Theme::warning(),
            Status::Critical => Theme::error(),
            Status::Unknown => Theme::muted_text(),
            Status::Offline => Theme::muted_text(),
        };

        // For sub-services, prefer latency if available
        let status_str = if let Some(latency) = info.latency_ms {
            if latency < 0.0 {
                "timeout".to_string()
            } else {
                format!("{:.0}ms", latency)
            }
        } else {
            info.status.clone()
        };
        let tree_symbol = if is_last { "└─" } else { "├─" };

        vec![
            // Indentation and tree prefix
            ratatui::text::Span::styled(
                format!("  {} ", tree_symbol),
                Typography::tree(),
            ),
            // Status icon
            ratatui::text::Span::styled(
                format!("{} ", icon),
                Style::default().fg(status_color).bg(Theme::background()),
            ),
            // Service name
            ratatui::text::Span::styled(
                format!("{:<18} ", short_name),
                Style::default()
                    .fg(Theme::secondary_text())
                    .bg(Theme::background()),
            ),
            // Status/latency text
            ratatui::text::Span::styled(
                status_str,
                Style::default()
                    .fg(Theme::secondary_text())
                    .bg(Theme::background()),
            ),
        ]
    }

    /// Move selection up
    pub fn select_previous(&mut self) {
        if self.selected_index > 0 {
            self.selected_index -= 1;
        }
        debug!("Service selection moved up to: {}", self.selected_index);
    }

    /// Move selection down  
    pub fn select_next(&mut self, total_services: usize) {
        if total_services > 0 && self.selected_index < total_services.saturating_sub(1) {
            self.selected_index += 1;
        }
        debug!("Service selection: {}/{}", self.selected_index, total_services);
    }

    /// Get currently selected service name (for actions)
    pub fn get_selected_service(&self) -> Option<String> {
        // Build the same display list to find the selected service
        let mut display_lines: Vec<(String, Status, bool, Option<(ServiceInfo, bool)>, String)> = Vec::new();
        
        let mut parent_services: Vec<_> = self.parent_services.iter().collect();
        parent_services.sort_by(|(a, _), (b, _)| a.cmp(b));

        for (parent_name, parent_info) in parent_services {
            let parent_line = self.format_parent_service_line(parent_name, parent_info);
            display_lines.push((parent_line, parent_info.widget_status, false, None, parent_name.clone()));
            
            if let Some(sub_list) = self.sub_services.get(parent_name) {
                let mut sorted_subs = sub_list.clone();
                sorted_subs.sort_by(|(a, _), (b, _)| a.cmp(b));
                
                for (i, (sub_name, sub_info)) in sorted_subs.iter().enumerate() {
                    let is_last_sub = i == sorted_subs.len() - 1;
                    let full_sub_name = format!("{}_{}", parent_name, sub_name);
                    display_lines.push((
                        sub_name.clone(),
                        sub_info.widget_status,
                        true,
                        Some((sub_info.clone(), is_last_sub)),
                        full_sub_name,
                    ));
                }
            }
        }
        
        display_lines.get(self.selected_index).map(|(_, _, _, _, raw_name)| raw_name.clone())
    }

    /// Get total count of selectable services (parent services only, not sub-services)
    pub fn get_total_services_count(&self) -> usize {
        // Only count parent services - sub-services are not selectable
        self.parent_services.len()
    }


    /// Calculate which parent service index corresponds to a display line index
    fn calculate_parent_service_index(&self, display_line_index: &usize) -> usize {
        // Build the same display list to map line index to parent service index
        let mut parent_index = 0;
        let mut line_index = 0;
        
        let mut parent_services: Vec<_> = self.parent_services.iter().collect();
        parent_services.sort_by(|(a, _), (b, _)| a.cmp(b));

        for (parent_name, _) in parent_services {
            if line_index == *display_line_index {
                return parent_index;
            }
            line_index += 1; // Parent service line
            
            // Skip sub-services but count them in line_index
            if let Some(sub_list) = self.sub_services.get(parent_name) {
                line_index += sub_list.len();
            }
            
            parent_index += 1;
        }
        
        // If we get here, the display_line_index was probably for a sub-service
        // Return the last valid parent index (should not happen with our logic)
        parent_index.saturating_sub(1)
    }
}

impl Widget for ServicesWidget {
    fn update_from_metrics(&mut self, metrics: &[&Metric]) {
        debug!("Services widget updating with {} metrics", metrics.len());

        // Don't clear existing services - preserve data between metric batches

        // Process individual service metrics
        for metric in metrics {
            if let Some((parent_service, sub_service)) = Self::extract_service_info(&metric.name) {
                match sub_service {
                    None => {
                        // Parent service metric
                        let service_info =
                            self.parent_services
                                .entry(parent_service)
                                .or_insert(ServiceInfo {
                                    status: "unknown".to_string(),
                                    memory_mb: None,
                                    disk_gb: None,
                                    latency_ms: None,
                                    widget_status: Status::Unknown,
                                });

                        if metric.name.ends_with("_status") {
                            service_info.status = metric.value.as_string();
                            service_info.widget_status = metric.status;
                        } else if metric.name.ends_with("_memory_mb") {
                            if let Some(memory) = metric.value.as_f32() {
                                service_info.memory_mb = Some(memory);
                            }
                        } else if metric.name.ends_with("_disk_gb") {
                            if let Some(disk) = metric.value.as_f32() {
                                service_info.disk_gb = Some(disk);
                            }
                        }
                    }
                    Some(sub_name) => {
                        // Sub-service metric
                        let sub_service_list = self
                            .sub_services
                            .entry(parent_service)
                            .or_insert_with(Vec::new);

                        // Find existing sub-service or create new one
                        let sub_service_info = if let Some(pos) = sub_service_list
                            .iter()
                            .position(|(name, _)| name == &sub_name)
                        {
                            &mut sub_service_list[pos].1
                        } else {
                            sub_service_list.push((
                                sub_name.clone(),
                                ServiceInfo {
                                    status: "unknown".to_string(),
                                    memory_mb: None,
                                    disk_gb: None,
                                    latency_ms: None,
                                    widget_status: Status::Unknown,
                                },
                            ));
                            &mut sub_service_list.last_mut().unwrap().1
                        };

                        if metric.name.ends_with("_status") {
                            sub_service_info.status = metric.value.as_string();
                            sub_service_info.widget_status = metric.status;
                        } else if metric.name.ends_with("_memory_mb") {
                            if let Some(memory) = metric.value.as_f32() {
                                sub_service_info.memory_mb = Some(memory);
                            }
                        } else if metric.name.ends_with("_disk_gb") {
                            if let Some(disk) = metric.value.as_f32() {
                                sub_service_info.disk_gb = Some(disk);
                            }
                        } else if metric.name.ends_with("_latency_ms") {
                            if let Some(latency) = metric.value.as_f32() {
                                sub_service_info.latency_ms = Some(latency);
                                sub_service_info.widget_status = metric.status;
                            }
                        }
                    }
                }
            }
        }

        // Aggregate status from all parent and sub-services
        let mut all_statuses = Vec::new();

        // Add parent service statuses
        all_statuses.extend(self.parent_services.values().map(|info| info.widget_status));

        // Add sub-service statuses
        for sub_list in self.sub_services.values() {
            all_statuses.extend(sub_list.iter().map(|(_, info)| info.widget_status));
        }

        self.status = if all_statuses.is_empty() {
            Status::Unknown
        } else {
            Status::aggregate(&all_statuses)
        };

        self.has_data = !self.parent_services.is_empty() || !self.sub_services.is_empty();

        // Ensure selection index is within bounds after update
        let total_count = self.get_total_services_count();
        if self.selected_index >= total_count && total_count > 0 {
            self.selected_index = total_count - 1;
        }

        debug!(
            "Services widget updated: {} parent services, {} sub-service groups, total={}, selected={}, status={:?}",
            self.parent_services.len(),
            self.sub_services.len(),
            total_count,
            self.selected_index,
            self.status
        );
    }

}

impl ServicesWidget {

    /// Render with focus
    pub fn render(&mut self, frame: &mut Frame, area: Rect, is_focused: bool) {
        let services_block = Components::widget_block("services");
        let inner_area = services_block.inner(area);
        frame.render_widget(services_block, area);

        let content_chunks = Layout::default()
            .direction(Direction::Vertical)
            .constraints([Constraint::Length(1), Constraint::Min(0)])
            .split(inner_area);

        // Header
        let header = format!(
            "{:<25} {:<10} {:<8} {:<8}",
            "Service:", "Status:", "RAM:", "Disk:"
        );
        let header_para = Paragraph::new(header).style(Typography::muted());
        frame.render_widget(header_para, content_chunks[0]);

        // Check if we have any services to display
        if self.parent_services.is_empty() && self.sub_services.is_empty() {
            let empty_text = Paragraph::new("No process data").style(Typography::muted());
            frame.render_widget(empty_text, content_chunks[1]);
            return;
        }

        // Render the services list
        self.render_services(frame, content_chunks[1], is_focused);
    }

    /// Render services list
    fn render_services(&mut self, frame: &mut Frame, area: Rect, is_focused: bool) {
        // Build hierarchical service list for display
        let mut display_lines: Vec<(String, Status, bool, Option<(ServiceInfo, bool)>)> = Vec::new();

        // Sort parent services alphabetically for consistent order
        let mut parent_services: Vec<_> = self.parent_services.iter().collect();
        parent_services.sort_by(|(a, _), (b, _)| a.cmp(b));

        for (parent_name, parent_info) in parent_services {
            // Add parent service line
            let parent_line = self.format_parent_service_line(parent_name, parent_info);
            display_lines.push((parent_line, parent_info.widget_status, false, None));

            // Add sub-services for this parent (if any)
            if let Some(sub_list) = self.sub_services.get(parent_name) {
                // Sort sub-services by name for consistent display
                let mut sorted_subs = sub_list.clone();
                sorted_subs.sort_by(|(a, _), (b, _)| a.cmp(b));

                for (i, (sub_name, sub_info)) in sorted_subs.iter().enumerate() {
                    let is_last_sub = i == sorted_subs.len() - 1;
                    // Store sub-service info for custom span rendering
                    display_lines.push((
                        sub_name.clone(),
                        sub_info.widget_status,
                        true,
                        Some((sub_info.clone(), is_last_sub)),
                    )); // true = sub-service, with is_last info
                }
            }
        }

        // Show only what fits, with "X more below" if needed
        let available_lines = area.height as usize;
        let total_lines = display_lines.len();
        
        // Reserve one line for "X more below" if needed
        let lines_for_content = if total_lines > available_lines {
            available_lines.saturating_sub(1)
        } else {
            available_lines
        };
        
        let visible_lines: Vec<_> = display_lines
            .iter()
            .take(lines_for_content)
            .collect();
        
        let hidden_below = total_lines.saturating_sub(lines_for_content);
        
        let lines_to_show = visible_lines.len();

        if lines_to_show > 0 {
            // Add space for "X more below" message if needed
            let total_chunks_needed = if hidden_below > 0 { lines_to_show + 1 } else { lines_to_show };
            let service_chunks = Layout::default()
                .direction(Direction::Vertical)
                .constraints(vec![Constraint::Length(1); total_chunks_needed])
                .split(area);

            for (i, (line_text, line_status, is_sub, sub_info)) in visible_lines.iter().enumerate()
            {
                let actual_index = i; // Simple index since we're not scrolling
                
                // Only parent services can be selected - calculate parent service index
                let is_selected = if !*is_sub {
                    // This is a parent service - count how many parent services came before this one
                    let parent_index = self.calculate_parent_service_index(&actual_index);
                    parent_index == self.selected_index
                } else {
                    false // Sub-services are never selected
                };
                
                let mut spans = if *is_sub && sub_info.is_some() {
                    // Use custom sub-service span creation
                    let (service_info, is_last) = sub_info.as_ref().unwrap();
                    self.create_sub_service_spans(line_text, service_info, *is_last)
                } else {
                    // Parent services - use normal status spans
                    StatusIcons::create_status_spans(*line_status, line_text)
                };
                
                // Apply selection highlighting to parent services only
                // Only show selection when Services panel is focused
                if is_selected && !*is_sub && is_focused {
                    for (i, span) in spans.iter_mut().enumerate() {
                        if i == 0 {
                            // First span is the status icon - use background color for visibility against blue selection
                            span.style = span.style
                                .bg(Theme::highlight())
                                .fg(Theme::background());
                        } else {
                            // Other spans (text) get full selection highlighting
                            span.style = span.style
                                .bg(Theme::highlight())
                                .fg(Theme::background());
                        }
                    }
                }
                
                let service_para = Paragraph::new(ratatui::text::Line::from(spans));
                
                frame.render_widget(service_para, service_chunks[i]);
            }
            
            // Show "X more below" message if content was truncated
            if hidden_below > 0 {
                let more_text = format!("... {} more below", hidden_below);
                let more_para = Paragraph::new(more_text).style(Typography::muted());
                frame.render_widget(more_para, service_chunks[lines_to_show]);
            }
        }
    }
}

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