use anyhow::Result;
use crossterm::event::{Event, KeyCode};
use ratatui::{
    layout::{Constraint, Direction, Layout, Rect},
    style::Style,
    widgets::{Block, Paragraph},
    Frame,
};
use std::time::Instant;
use tracing::info;

pub mod widgets;
pub mod theme;

use widgets::{CpuWidget, MemoryWidget, ServicesWidget, BackupWidget, Widget};
use crate::metrics::{MetricStore, WidgetType};
use cm_dashboard_shared::{Metric, Status};
use theme::{Theme, Layout as ThemeLayout, Typography, Components, StatusIcons};

/// Main TUI application
pub struct TuiApp {
    /// CPU widget
    cpu_widget: CpuWidget,
    /// Memory widget
    memory_widget: MemoryWidget,
    /// Services widget
    services_widget: ServicesWidget,
    /// Backup widget
    backup_widget: BackupWidget,
    /// Current active host
    current_host: Option<String>,
    /// Available hosts
    available_hosts: Vec<String>,
    /// Host index for navigation
    host_index: usize,
    /// Last update time
    last_update: Option<Instant>,
    /// Should quit application
    should_quit: bool,
}

impl TuiApp {
    pub fn new() -> Self {
        Self {
            cpu_widget: CpuWidget::new(),
            memory_widget: MemoryWidget::new(),
            services_widget: ServicesWidget::new(),
            backup_widget: BackupWidget::new(),
            current_host: None,
            available_hosts: Vec::new(),
            host_index: 0,
            last_update: None,
            should_quit: false,
        }
    }
    
    /// Update widgets with metrics from store
    pub fn update_metrics(&mut self, metric_store: &MetricStore) {
        if let Some(ref hostname) = self.current_host {
            // Update CPU widget
            let cpu_metrics = metric_store.get_metrics_for_widget(hostname, WidgetType::Cpu);
            self.cpu_widget.update_from_metrics(&cpu_metrics);
            
            // Update Memory widget
            let memory_metrics = metric_store.get_metrics_for_widget(hostname, WidgetType::Memory);
            self.memory_widget.update_from_metrics(&memory_metrics);
            
            // Update Services widget - get all metrics that start with "service_"
            let all_metrics = metric_store.get_metrics_for_host(hostname);
            let service_metrics: Vec<&Metric> = all_metrics.iter()
                .filter(|m| m.name.starts_with("service_"))
                .copied()
                .collect();
            self.services_widget.update_from_metrics(&service_metrics);
            
            // Update Backup widget - get all metrics that start with "backup_"
            let all_backup_metrics: Vec<&Metric> = all_metrics.iter()
                .filter(|m| m.name.starts_with("backup_"))
                .copied()
                .collect();
            self.backup_widget.update_from_metrics(&all_backup_metrics);
            
            self.last_update = Some(Instant::now());
        }
    }
    
    /// Update available hosts
    pub fn update_hosts(&mut self, hosts: Vec<String>) {
        self.available_hosts = hosts;
        
        // Set current host if none selected
        if self.current_host.is_none() && !self.available_hosts.is_empty() {
            self.current_host = Some(self.available_hosts[0].clone());
            self.host_index = 0;
        }
    }
    
    /// Handle keyboard input
    pub fn handle_input(&mut self, event: Event) -> Result<()> {
        if let Event::Key(key) = event {
            match key.code {
                KeyCode::Char('q') => {
                    self.should_quit = true;
                }
                KeyCode::Left => {
                    self.navigate_host(-1);
                }
                KeyCode::Right => {
                    self.navigate_host(1);
                }
                KeyCode::Char('r') => {
                    info!("Manual refresh requested");
                    // Refresh will be handled by main loop
                }
                KeyCode::Tab => {
                    self.navigate_host(1); // Tab cycles to next host
                }
                _ => {}
            }
        }
        Ok(())
    }
    
    /// Navigate between hosts
    fn navigate_host(&mut self, direction: i32) {
        if self.available_hosts.is_empty() {
            return;
        }
        
        let len = self.available_hosts.len();
        if direction > 0 {
            self.host_index = (self.host_index + 1) % len;
        } else {
            self.host_index = if self.host_index == 0 { len - 1 } else { self.host_index - 1 };
        }
        
        self.current_host = Some(self.available_hosts[self.host_index].clone());
        info!("Switched to host: {}", self.current_host.as_ref().unwrap());
    }
    
    
    /// Render the dashboard (real btop-style multi-panel layout)
    pub fn render(&mut self, frame: &mut Frame, metric_store: &MetricStore) {
        let size = frame.size();
        
        // Clear background to true black like btop
        frame.render_widget(
            Block::default().style(Style::default().bg(Theme::background())), 
            size
        );
        
        // Create real btop-style layout: multi-panel with borders
        // Top section: title bar
        // Bottom section: split into left (mem + disks) and right (CPU + processes)
        let main_chunks = Layout::default()
            .direction(Direction::Vertical)
            .constraints([
                Constraint::Length(1),    // Title bar
                Constraint::Min(0),       // Main content area
            ])
            .split(size);
        
        // New layout: left panels | right services (100% height)
        let content_chunks = ratatui::layout::Layout::default()
            .direction(Direction::Horizontal)
            .constraints([
                Constraint::Percentage(ThemeLayout::LEFT_PANEL_WIDTH),   // Left side: system, backup
                Constraint::Percentage(ThemeLayout::RIGHT_PANEL_WIDTH),  // Right side: services (100% height)
            ])
            .split(main_chunks[1]);
        
        // Left side: system on top, backup on bottom (equal height)
        let left_chunks = ratatui::layout::Layout::default()
            .direction(Direction::Vertical)
            .constraints([
                Constraint::Percentage(ThemeLayout::SYSTEM_PANEL_HEIGHT),  // System section
                Constraint::Percentage(ThemeLayout::BACKUP_PANEL_HEIGHT),  // Backup section
            ])
            .split(content_chunks[0]);
        
        // Render title bar
        self.render_btop_title(frame, main_chunks[0]);
        
        // Render new panel layout
        self.render_system_panel(frame, left_chunks[0], metric_store);
        self.render_backup_panel(frame, left_chunks[1]);
        self.services_widget.render(frame, content_chunks[1]);  // Services takes full right side
    }
    
    /// Render btop-style minimal title
    fn render_btop_title(&self, frame: &mut Frame, area: Rect) {
        use ratatui::text::{Line, Span};
        use ratatui::style::Modifier;
        
        if self.available_hosts.is_empty() {
            let title_text = "cm-dashboard • no hosts discovered";
            let title = Paragraph::new(title_text)
                .style(Typography::title());
            frame.render_widget(title, area);
            return;
        }
        
        // Create spans for each host
        let mut spans = vec![Span::styled("cm-dashboard • ", Typography::title())];
        
        for (i, host) in self.available_hosts.iter().enumerate() {
            if i > 0 {
                spans.push(Span::styled(" ", Typography::title()));
            }
            
            if Some(host) == self.current_host.as_ref() {
                // Selected host in bold bright white
                spans.push(Span::styled(
                    host.clone(),
                    Typography::title().add_modifier(Modifier::BOLD)
                ));
            } else {
                // Other hosts in normal style
                spans.push(Span::styled(host.clone(), Typography::title()));
            }
        }
        
        let title_line = Line::from(spans);
        let title = Paragraph::new(vec![title_line]);
        
        frame.render_widget(title, area);
    }
    
    
    
    fn render_system_panel(&mut self, frame: &mut Frame, area: Rect, metric_store: &MetricStore) {
        let system_block = Components::widget_block("system");
        let inner_area = system_block.inner(area);
        frame.render_widget(system_block, area);
        let content_chunks = ratatui::layout::Layout::default()
            .direction(Direction::Vertical)
            .constraints([
                Constraint::Length(ThemeLayout::CPU_SECTION_HEIGHT),     // CPU section (title, load)
                Constraint::Length(ThemeLayout::MEMORY_SECTION_HEIGHT),  // Memory section (title, used, /tmp)
                Constraint::Min(0)                                       // Storage section
            ])
            .split(inner_area);
        
        self.cpu_widget.render(frame, content_chunks[0]);
        self.memory_widget.render(frame, content_chunks[1]);
        self.render_storage_section(frame, content_chunks[2], metric_store);
    }
    
    fn render_backup_panel(&mut self, frame: &mut Frame, area: Rect) {
        let backup_block = Components::widget_block("backup");
        let inner_area = backup_block.inner(area);
        frame.render_widget(backup_block, area);
        self.backup_widget.render(frame, inner_area);
    }
    
    
    fn render_storage_section(&self, frame: &mut Frame, area: Rect, metric_store: &MetricStore) {
        if area.height < 2 {
            return;
        }

        if let Some(ref hostname) = self.current_host {
            // Get disk count to determine how many disks to display
            let disk_count = if let Some(count_metric) = metric_store.get_metric(hostname, "disk_count") {
                count_metric.value.as_i64().unwrap_or(0) as usize
            } else {
                0
            };

            if disk_count == 0 {
                // No disks found - show error/waiting message
                let content_chunks = ratatui::layout::Layout::default()
                    .direction(Direction::Vertical)
                    .constraints([Constraint::Length(1), Constraint::Min(0)])
                    .split(area);

                let disk_title = Paragraph::new("Storage:").style(Typography::widget_title());
                frame.render_widget(disk_title, content_chunks[0]);

                let no_disks_spans = StatusIcons::create_status_spans(Status::Unknown, "No mounted disks detected");
                let no_disks_para = Paragraph::new(ratatui::text::Line::from(no_disks_spans));
                frame.render_widget(no_disks_para, content_chunks[1]);
                return;
            }

            // Group disks by physical device
            let mut physical_devices: std::collections::HashMap<String, Vec<usize>> = std::collections::HashMap::new();
            
            for disk_index in 0..disk_count {
                if let Some(physical_device_metric) = metric_store.get_metric(hostname, &format!("disk_{}_physical_device", disk_index)) {
                    let physical_device = physical_device_metric.value.as_string();
                    physical_devices.entry(physical_device).or_insert_with(Vec::new).push(disk_index);
                }
            }

            // Calculate how many lines we need
            let mut total_lines_needed = 0;
            for partitions in physical_devices.values() {
                total_lines_needed += 2 + partitions.len(); // title + health + usage_per_partition
            }

            let available_lines = area.height as usize;
            
            // Create constraints dynamically based on physical devices
            let mut constraints = Vec::new();
            let mut devices_to_show = Vec::new();
            let mut current_line = 0;

            for (physical_device, partitions) in &physical_devices {
                let lines_for_this_device = 2 + partitions.len();
                if current_line + lines_for_this_device <= available_lines {
                    devices_to_show.push((physical_device.clone(), partitions.clone()));
                    
                    // Add constraints for this device
                    constraints.push(Constraint::Length(1)); // Device title
                    constraints.push(Constraint::Length(1)); // Health line
                    for _ in 0..partitions.len() {
                        constraints.push(Constraint::Length(1)); // Usage line per partition
                    }
                    
                    current_line += lines_for_this_device;
                } else {
                    break; // Can't fit more devices
                }
            }

            // Add remaining space if any
            if constraints.len() < available_lines {
                constraints.push(Constraint::Min(0));
            }

            let content_chunks = ratatui::layout::Layout::default()
                .direction(Direction::Vertical)
                .constraints(constraints)
                .split(area);

            let mut chunk_index = 0;

            // Display each physical device
            for (physical_device, partitions) in &devices_to_show {
                // Device title
                let disk_title_text = format!("Disk {}:", physical_device);
                let disk_title_para = Paragraph::new(disk_title_text).style(Typography::widget_title());
                frame.render_widget(disk_title_para, content_chunks[chunk_index]);
                chunk_index += 1;

                // Health status (one per physical device)
                let smart_health = metric_store.get_metric(hostname, &format!("disk_smart_{}_health", physical_device))
                    .map(|m| (m.value.as_string(), m.status))
                    .unwrap_or_else(|| ("Unknown".to_string(), Status::Unknown));

                let smart_temp = metric_store.get_metric(hostname, &format!("disk_smart_{}_temperature", physical_device))
                    .and_then(|m| m.value.as_f32());

                let temp_text = if let Some(temp) = smart_temp {
                    format!(" {}°C", temp as i32)
                } else {
                    String::new()
                };

                let health_spans = StatusIcons::create_status_spans(
                    smart_health.1,
                    &format!("Health: {}{}", smart_health.0, temp_text)
                );
                let health_para = Paragraph::new(ratatui::text::Line::from(health_spans));
                frame.render_widget(health_para, content_chunks[chunk_index]);
                chunk_index += 1;

                // Usage lines (one per partition/mount point)
                for &disk_index in partitions {
                    let mount_point = metric_store.get_metric(hostname, &format!("disk_{}_mount_point", disk_index))
                        .map(|m| m.value.as_string())
                        .unwrap_or("?".to_string());

                    let usage_percent = metric_store.get_metric(hostname, &format!("disk_{}_usage_percent", disk_index))
                        .and_then(|m| m.value.as_f32())
                        .unwrap_or(0.0);

                    let used_gb = metric_store.get_metric(hostname, &format!("disk_{}_used_gb", disk_index))
                        .and_then(|m| m.value.as_f32())
                        .unwrap_or(0.0);

                    let total_gb = metric_store.get_metric(hostname, &format!("disk_{}_total_gb", disk_index))
                        .and_then(|m| m.value.as_f32())
                        .unwrap_or(0.0);

                    let usage_status = metric_store.get_metric(hostname, &format!("disk_{}_usage_percent", disk_index))
                        .map(|m| m.status)
                        .unwrap_or(Status::Unknown);

                    // Format mount point for usage line  
                    let mount_display = if mount_point == "/" {
                        "root".to_string()
                    } else if mount_point == "/boot" {
                        "boot".to_string()
                    } else if mount_point.starts_with("/") {
                        mount_point[1..].to_string() // Remove leading slash
                    } else {
                        mount_point.clone()
                    };

                    let usage_spans = StatusIcons::create_status_spans(
                        usage_status,
                        &format!("Usage @{}: {:.1}% • {:.1}/{:.1} GB", mount_display, usage_percent, used_gb, total_gb)
                    );
                    let usage_para = Paragraph::new(ratatui::text::Line::from(usage_spans));
                    frame.render_widget(usage_para, content_chunks[chunk_index]);
                    chunk_index += 1;
                }
            }

            // Show truncation indicator if we couldn't display all devices
            if devices_to_show.len() < physical_devices.len() {
                if let Some(last_chunk) = content_chunks.last() {
                    let truncated_count = physical_devices.len() - devices_to_show.len();
                    let truncated_text = format!("... and {} more disk{}", 
                        truncated_count,
                        if truncated_count == 1 { "" } else { "s" });
                    let truncated_para = Paragraph::new(truncated_text).style(Typography::muted());
                    frame.render_widget(truncated_para, *last_chunk);
                }
            }
        } else {
            // No host connected
            let content_chunks = ratatui::layout::Layout::default()
                .direction(Direction::Vertical)
                .constraints([Constraint::Length(1), Constraint::Min(0)])
                .split(area);

            let disk_title = Paragraph::new("Storage:").style(Typography::widget_title());
            frame.render_widget(disk_title, content_chunks[0]);

            let no_host_spans = StatusIcons::create_status_spans(Status::Unknown, "No host connected");
            let no_host_para = Paragraph::new(ratatui::text::Line::from(no_host_spans));
            frame.render_widget(no_host_para, content_chunks[1]);
        }
    }
    
}