cqlite-cli 0.11.0

use crate::config::Config;
use crate::status_metrics::{HealthIndicator, StatusMetrics, METRICS_REFRESH_INTERVAL};
use anyhow::Result;
use cqlite_core::Database;
use crossterm::{
    event::{self, DisableMouseCapture, EnableMouseCapture, Event, KeyCode, KeyModifiers},
    execute,
    terminal::{disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen},
};
use ratatui::{
    backend::{Backend, CrosstermBackend},
    layout::{Constraint, Direction, Layout, Rect},
    style::{Color, Modifier, Style},
    text::{Line, Span},
    widgets::{
        Block, Borders, Cell, List, ListItem, ListState, Paragraph, Row, Table, TableState, Wrap,
    },
    Frame, Terminal,
};
use std::path::Path;
use std::sync::Arc;
use std::time::{Duration, Instant};

pub async fn start_tui_mode(db_path: &Path, config: &Config, database: Database) -> Result<()> {
    // CRITICAL: Disable all logging to prevent messages from bleeding into TUI display
    // env_logger is already initialized in main.rs, so we can't reinitialize it.
    // Instead, set the global max log level to Off to suppress all log output.
    log::set_max_level(log::LevelFilter::Off);

    // Initialize the database
    let db = Arc::new(database);

    // Setup terminal
    enable_raw_mode()?;
    let mut stdout = std::io::stdout();
    execute!(stdout, EnterAlternateScreen, EnableMouseCapture)?;
    let backend = CrosstermBackend::new(stdout);
    let mut terminal = Terminal::new(backend)?;

    // Create app state
    let mut app = TuiApp::new(db_path, config, db).await?;
    let res = run_tui(&mut terminal, &mut app).await;

    // Restore terminal
    disable_raw_mode()?;
    execute!(
        terminal.backend_mut(),
        LeaveAlternateScreen,
        DisableMouseCapture
    )?;
    terminal.show_cursor()?;

    if let Err(err) = res {
        println!("{:?}", err)
    }

    Ok(())
}

// =============================================================================
// Panel State Structures (Issue #251)
// =============================================================================

/// Panel visibility configuration - toggleable with F2/F3/F4 keys
#[derive(Debug, Clone, Copy)]
struct PanelVisibility {
    tables: bool,  // F2 toggle - Tables browser panel
    results: bool, // F3 toggle - Query results panel
    history: bool, // F4 toggle - Query history panel
}

impl Default for PanelVisibility {
    fn default() -> Self {
        Self {
            tables: true,
            results: true,
            history: true,
        }
    }
}

impl PanelVisibility {
    /// Reset to default layout (F5)
    fn reset(&mut self) {
        *self = Self::default();
    }
}

/// Active panel for keyboard focus navigation
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum FocusPanel {
    Tables,
    Results,
    History,
    Input,
}

impl FocusPanel {
    /// Cycle to next visible panel (Tab key)
    fn next(self, visibility: &PanelVisibility) -> Self {
        let order = [
            (FocusPanel::Tables, visibility.tables),
            (FocusPanel::Results, visibility.results),
            (FocusPanel::History, visibility.history),
            (FocusPanel::Input, true), // Input always visible
        ];

        let current_idx = order.iter().position(|(p, _)| *p == self).unwrap_or(3);

        // Find next visible panel
        for i in 1..=order.len() {
            let next_idx = (current_idx + i) % order.len();
            if order[next_idx].1 {
                return order[next_idx].0;
            }
        }
        FocusPanel::Input // Fallback
    }

    /// Cycle to previous visible panel (Shift+Tab key)
    fn prev(self, visibility: &PanelVisibility) -> Self {
        let order = [
            (FocusPanel::Tables, visibility.tables),
            (FocusPanel::Results, visibility.results),
            (FocusPanel::History, visibility.history),
            (FocusPanel::Input, true),
        ];

        let current_idx = order.iter().position(|(p, _)| *p == self).unwrap_or(3);

        for i in 1..=order.len() {
            let prev_idx = (current_idx + order.len() - i) % order.len();
            if order[prev_idx].1 {
                return order[prev_idx].0;
            }
        }
        FocusPanel::Input
    }
}

/// Table entry in the tables browser
#[derive(Debug, Clone)]
struct TableEntry {
    #[allow(dead_code)] // Reserved for keyspace display
    keyspace: String,
    #[allow(dead_code)] // Reserved for table name display
    name: String,
    qualified_name: String, // "keyspace.table"
}

/// Tables browser panel state
#[derive(Debug)]
struct TablesBrowserState {
    entries: Vec<TableEntry>,
    filtered_indices: Vec<usize>, // Indices into entries after filter
    filter_text: String,
    filter_active: bool, // Is filter input mode active
    list_state: ListState,
}

impl Default for TablesBrowserState {
    fn default() -> Self {
        Self {
            entries: Vec::new(),
            filtered_indices: Vec::new(),
            filter_text: String::new(),
            filter_active: false,
            list_state: ListState::default(),
        }
    }
}

impl TablesBrowserState {
    /// Apply filter to entries and update filtered_indices
    fn apply_filter(&mut self) {
        if self.filter_text.is_empty() {
            self.filtered_indices = (0..self.entries.len()).collect();
        } else {
            let filter_lower = self.filter_text.to_lowercase();
            self.filtered_indices = self
                .entries
                .iter()
                .enumerate()
                .filter(|(_, e)| e.qualified_name.to_lowercase().contains(&filter_lower))
                .map(|(i, _)| i)
                .collect();
        }
        // Reset selection if out of bounds
        if let Some(selected) = self.list_state.selected() {
            if selected >= self.filtered_indices.len() {
                if self.filtered_indices.is_empty() {
                    self.list_state.select(None);
                } else {
                    self.list_state.select(Some(0));
                }
            }
        }
    }

    /// Get currently selected entry
    fn selected_entry(&self) -> Option<&TableEntry> {
        self.list_state
            .selected()
            .and_then(|idx| self.filtered_indices.get(idx))
            .and_then(|&entry_idx| self.entries.get(entry_idx))
    }
}

/// Query results table state with scroll tracking
#[derive(Debug)]
struct ResultsTableState {
    columns: Vec<String>,
    rows: Vec<Vec<String>>,
    row_offset: usize, // Vertical scroll position
    col_offset: usize, // Horizontal scroll position (column index)
    selected_row: Option<usize>,
    column_widths: Vec<u16>, // Calculated widths for each column
    table_state: TableState,
}

impl Default for ResultsTableState {
    fn default() -> Self {
        Self {
            columns: Vec::new(),
            rows: Vec::new(),
            row_offset: 0,
            col_offset: 0,
            selected_row: None,
            column_widths: Vec::new(),
            table_state: TableState::default(),
        }
    }
}

impl ResultsTableState {
    /// Calculate column widths based on content
    fn calculate_widths(&mut self) {
        if self.columns.is_empty() {
            self.column_widths = vec![];
            return;
        }

        // Start with header widths (minimum width)
        let mut widths: Vec<u16> = self.columns.iter().map(|c| c.len() as u16).collect();

        // Expand for content (sample first 100 rows)
        for row in self.rows.iter().take(100) {
            for (i, cell) in row.iter().enumerate() {
                if i < widths.len() {
                    widths[i] = widths[i].max(cell.len() as u16);
                }
            }
        }

        // Add padding (2 spaces) and cap at 40 chars
        for w in &mut widths {
            *w = (*w + 2).min(40);
        }

        self.column_widths = widths;
    }

    /// Get visible columns range based on offset and available width
    fn visible_columns(&self, available_width: u16) -> std::ops::Range<usize> {
        if self.column_widths.is_empty() {
            return 0..0;
        }

        let start = self
            .col_offset
            .min(self.column_widths.len().saturating_sub(1));
        let mut end = start;
        let mut used_width = 0u16;

        for i in start..self.column_widths.len() {
            let col_width = self.column_widths.get(i).copied().unwrap_or(10);
            if used_width + col_width > available_width && end > start {
                break;
            }
            used_width += col_width;
            end = i + 1;
        }

        start..end.max(start + 1).min(self.columns.len())
    }

    /// Check if there are more columns to the left
    fn has_scroll_left(&self) -> bool {
        self.col_offset > 0
    }

    /// Check if there are more columns to the right
    fn has_scroll_right(&self, available_width: u16) -> bool {
        let visible = self.visible_columns(available_width);
        visible.end < self.columns.len()
    }

    /// Clear results
    fn clear(&mut self) {
        self.columns.clear();
        self.rows.clear();
        self.row_offset = 0;
        self.col_offset = 0;
        self.selected_row = None;
        self.column_widths.clear();
        self.table_state = TableState::default();
    }
}

/// Layout areas computed from panel visibility
struct LayoutAreas {
    header: Rect,
    tables: Option<Rect>,
    results: Option<Rect>,
    history: Option<Rect>,
    input: Rect,
    status: Rect,
}

// =============================================================================
// TUI Application State
// =============================================================================

/// TUI Application State
struct TuiApp {
    db_path: std::path::PathBuf,
    database: Arc<Database>,
    input: String,
    #[allow(dead_code)] // Legacy mode - replaced by focus_panel
    input_mode: InputMode,
    messages: Vec<String>,
    #[allow(dead_code)] // Reserved for future scroll implementation
    scroll_offset: usize,
    history: Vec<String>,
    history_index: Option<usize>,
    query_results: Vec<QueryDisplayResult>,
    #[allow(dead_code)] // Legacy - replaced by history_scroll
    results_scroll: ListState,
    show_help: bool,
    status_message: String,
    #[allow(dead_code)] // Reserved for future use
    last_execution_time: Option<Duration>,
    /// Status metrics for enhanced status bar (Issue #242)
    status_metrics: Option<StatusMetrics>,
    /// Last time metrics were refreshed
    metrics_last_updated: Option<Instant>,

    // Issue #251: Multi-panel layout fields
    /// Panel visibility state (F2/F3/F4 toggles)
    panel_visibility: PanelVisibility,
    /// Currently focused panel for keyboard navigation
    focus_panel: FocusPanel,
    /// Tables browser panel state
    tables_browser: TablesBrowserState,
    /// Query results table with horizontal scrolling
    results_table: ResultsTableState,
    /// History panel scroll state
    history_scroll: ListState,
    /// Current keyspace context for header display
    current_keyspace: Option<String>,
}

#[derive(Clone, PartialEq)]
#[allow(dead_code)] // Normal variant reserved for future use
enum InputMode {
    Normal,
    Editing,
    Results,
    Help,
}

#[derive(Clone)]
struct QueryDisplayResult {
    query: String,
    success: bool,
    #[allow(dead_code)] // Row count - used in History panel display
    rows: usize,
    execution_time: Option<Duration>,
    #[allow(dead_code)] // Reserved for future error display
    error_message: Option<String>,
}

impl TuiApp {
    async fn new(db_path: &Path, config: &Config, database: Arc<Database>) -> Result<Self> {
        // Collect initial metrics
        let initial_metrics = StatusMetrics::collect(Some(db_path), Some(&database)).await;

        // Create initial app state
        let mut app = TuiApp {
            db_path: db_path.to_path_buf(),
            database,
            input: String::new(),
            input_mode: InputMode::Editing,
            messages: vec![
                "Welcome to CQLite TUI Mode!".to_string(),
                "Type CQL queries and press Enter to execute.".to_string(),
                "Press F1 for help, Tab to navigate panels, Esc to exit.".to_string(),
                String::new(),
            ],
            scroll_offset: 0,
            history: Vec::new(),
            history_index: None,
            query_results: Vec::new(),
            results_scroll: ListState::default(),
            show_help: false,
            status_message: "Ready".to_string(),
            last_execution_time: None,
            status_metrics: Some(initial_metrics),
            metrics_last_updated: Some(Instant::now()),
            // Issue #251: Multi-panel layout initialization
            panel_visibility: PanelVisibility::default(),
            focus_panel: FocusPanel::Input,
            tables_browser: TablesBrowserState::default(),
            results_table: ResultsTableState::default(),
            history_scroll: ListState::default(),
            current_keyspace: None,
        };

        // Load tables for browser panel (Issue #251)
        app.load_tables(config).await;

        Ok(app)
    }

    /// Check if metrics need refresh (stale after METRICS_REFRESH_INTERVAL)
    fn metrics_stale(&self) -> bool {
        match self.metrics_last_updated {
            Some(last) => last.elapsed() > METRICS_REFRESH_INTERVAL,
            None => true,
        }
    }

    /// Refresh status metrics if stale
    async fn refresh_metrics(&mut self) {
        if self.metrics_stale() {
            self.status_metrics =
                Some(StatusMetrics::collect(Some(&self.db_path), Some(&self.database)).await);
            self.metrics_last_updated = Some(Instant::now());
        }
    }

    /// Load tables into the tables browser (Issue #251)
    ///
    /// Uses the data directory scanning approach from REPL session fallback.
    /// This scans the filesystem for table directories since we don't have
    /// a ReplSession instance in TUI mode.
    async fn load_tables(&mut self, config: &Config) {
        // Get data directory from config
        let data_dir = match &config.data_directory {
            Some(dir) if !dir.as_os_str().is_empty() => dir,
            _ => {
                // No data directory configured - tables panel will be empty
                return;
            }
        };

        // Scan data directory for tables
        match self.scan_tables(data_dir).await {
            Ok(tables) => {
                self.tables_browser.entries = tables;
                self.tables_browser.apply_filter();

                // Select first entry if available
                if !self.tables_browser.filtered_indices.is_empty() {
                    self.tables_browser.list_state.select(Some(0));
                }
            }
            Err(e) => {
                // Log error but don't fail initialization - empty table list is acceptable
                eprintln!("Warning: Failed to load tables: {}", e);
            }
        }
    }

    /// Scan data directory for table entries
    ///
    /// This is adapted from ReplSession::scan_data_directory_tables but
    /// returns TableEntry structs suitable for the TUI browser.
    async fn scan_tables(&self, data_dir: &Path) -> Result<Vec<TableEntry>> {
        use std::fs;

        let mut entries = Vec::new();

        // Scan all keyspace directories
        let read_dir = fs::read_dir(data_dir)
            .map_err(|e| anyhow::anyhow!("Failed to read data directory: {}", e))?;

        for entry in read_dir {
            let entry =
                entry.map_err(|e| anyhow::anyhow!("Failed to read directory entry: {}", e))?;

            if !entry.path().is_dir() {
                continue;
            }

            let keyspace_name = match entry.file_name().to_str() {
                Some(name) if !name.starts_with('.') && name != "system" => name.to_string(),
                _ => continue,
            };

            // Scan tables in this keyspace
            let keyspace_dir = entry.path();
            let table_read_dir = match fs::read_dir(&keyspace_dir) {
                Ok(rd) => rd,
                Err(_) => continue, // Skip unreadable keyspace directories
            };

            for table_entry in table_read_dir {
                let table_entry = match table_entry {
                    Ok(e) => e,
                    Err(_) => continue,
                };

                if !table_entry.path().is_dir() {
                    continue;
                }

                if let Some(dir_name) = table_entry.file_name().to_str() {
                    if let Some(table_name) = extract_table_name(dir_name) {
                        entries.push(TableEntry {
                            keyspace: keyspace_name.clone(),
                            name: table_name.clone(),
                            qualified_name: format!("{}.{}", keyspace_name, table_name),
                        });
                    }
                }
            }
        }

        // Sort by qualified name for consistent ordering
        entries.sort_by(|a, b| a.qualified_name.cmp(&b.qualified_name));

        Ok(entries)
    }

    /// Execute a CQL query
    async fn execute_query(&mut self) {
        if self.input.trim().is_empty() {
            return;
        }

        let query = self.input.trim().to_string();
        self.history.push(query.clone());
        self.history_index = None;

        self.status_message = "Executing query...".to_string();

        let start_time = std::time::Instant::now();
        match self.database.execute(&query).await {
            Ok(result) => {
                let execution_time = start_time.elapsed();
                self.last_execution_time = Some(execution_time);

                let display_result = QueryDisplayResult {
                    query: query.clone(),
                    success: true,
                    rows: result.rows.len(),
                    execution_time: Some(execution_time),
                    error_message: None,
                };

                self.query_results.insert(0, display_result);

                // Add result summary to messages
                if result.rows.is_empty() && result.rows_affected > 0 {
                    self.messages.push(format!(
                        "✓ Query executed: {} rows affected ({})",
                        result.rows_affected,
                        format_duration(execution_time)
                    ));
                    // Clear results table for non-SELECT queries
                    self.results_table.clear();
                } else {
                    self.messages.push(format!(
                        "✓ Query executed: {} rows returned ({})",
                        result.rows.len(),
                        format_duration(execution_time)
                    ));

                    // Populate results table for display (Issue #251)
                    if !result.rows.is_empty() {
                        let column_names = result.rows[0].column_names();
                        self.results_table.columns = column_names.clone();
                        self.results_table.rows = result
                            .rows
                            .iter()
                            .map(|row| {
                                column_names
                                    .iter()
                                    .map(|col| {
                                        row.get(col)
                                            .map(|v| v.to_string())
                                            .unwrap_or_else(|| "NULL".to_string())
                                    })
                                    .collect()
                            })
                            .collect();
                        self.results_table.row_offset = 0;
                        self.results_table.col_offset = 0;
                        self.results_table.calculate_widths();

                        // Also add to messages for scrollback
                        self.messages
                            .push(format!("Columns: {}", column_names.join(", ")));
                    } else {
                        self.results_table.clear();
                    }
                }

                self.status_message =
                    format!("Query completed in {}", format_duration(execution_time));
            }
            Err(e) => {
                let execution_time = start_time.elapsed();

                let display_result = QueryDisplayResult {
                    query: query.clone(),
                    success: false,
                    rows: 0,
                    execution_time: Some(execution_time),
                    error_message: Some(e.to_string()),
                };

                self.query_results.insert(0, display_result);
                self.messages.push(format!("✗ Query failed: {}", e));
                self.status_message = "Query failed".to_string();
                // Don't clear results on error - keep previous results visible
            }
        }

        // Keep only last 20 results
        if self.query_results.len() > 20 {
            self.query_results.truncate(20);
        }

        // Keep only last 100 messages
        if self.messages.len() > 100 {
            self.messages.drain(0..self.messages.len() - 100);
        }

        self.input.clear();
    }

    /// Handle navigation in query history
    fn navigate_history(&mut self, up: bool) {
        if self.history.is_empty() {
            return;
        }

        if up {
            let index = match self.history_index {
                None => self.history.len() - 1,
                Some(i) if i > 0 => i - 1,
                Some(_) => return,
            };
            self.history_index = Some(index);
            self.input = self.history[index].clone();
        } else {
            match self.history_index {
                None => return,
                Some(i) if i < self.history.len() - 1 => {
                    self.history_index = Some(i + 1);
                    self.input = self.history[i + 1].clone();
                }
                Some(_) => {
                    self.history_index = None;
                    self.input.clear();
                }
            }
        }
    }
}

/// Main TUI event loop
async fn run_tui<B: Backend>(terminal: &mut Terminal<B>, app: &mut TuiApp) -> Result<()> {
    loop {
        // Refresh metrics if stale (every 5 seconds)
        app.refresh_metrics().await;

        terminal.draw(|f| ui(f, app))?;

        if event::poll(Duration::from_millis(100))? {
            if let Event::Key(key) = event::read()? {
                // Handle key events
                if handle_key_event(app, key).await {
                    return Ok(()); // Exit requested
                }
            }
        }
    }
}

/// Handle key events - returns true if should exit
async fn handle_key_event(app: &mut TuiApp, key: event::KeyEvent) -> bool {
    // Help mode - any key closes it
    if app.show_help {
        app.show_help = false;
        return false;
    }

    // Filter input mode in tables panel - handle specially
    if app.tables_browser.filter_active {
        return handle_filter_key(app, key);
    }

    // Global keybindings (always active)
    match key.code {
        KeyCode::F(1) => {
            app.show_help = true;
            return false;
        }
        KeyCode::F(2) => {
            app.panel_visibility.tables = !app.panel_visibility.tables;
            // Adjust focus if hiding current panel
            if !app.panel_visibility.tables && app.focus_panel == FocusPanel::Tables {
                app.focus_panel = app.focus_panel.next(&app.panel_visibility);
            }
            return false;
        }
        KeyCode::F(3) => {
            app.panel_visibility.results = !app.panel_visibility.results;
            if !app.panel_visibility.results && app.focus_panel == FocusPanel::Results {
                app.focus_panel = app.focus_panel.next(&app.panel_visibility);
            }
            return false;
        }
        KeyCode::F(4) => {
            app.panel_visibility.history = !app.panel_visibility.history;
            if !app.panel_visibility.history && app.focus_panel == FocusPanel::History {
                app.focus_panel = app.focus_panel.next(&app.panel_visibility);
            }
            return false;
        }
        KeyCode::F(5) => {
            app.panel_visibility.reset();
            return false;
        }
        KeyCode::Esc => {
            return true; // Exit
        }
        KeyCode::Tab => {
            app.focus_panel = app.focus_panel.next(&app.panel_visibility);
            return false;
        }
        KeyCode::BackTab => {
            app.focus_panel = app.focus_panel.prev(&app.panel_visibility);
            return false;
        }
        KeyCode::Char('c') if key.modifiers.contains(KeyModifiers::CONTROL) => {
            return true; // Ctrl+C exits
        }
        KeyCode::Char('l') if key.modifiers.contains(KeyModifiers::CONTROL) => {
            app.messages.clear();
            app.query_results.clear();
            app.results_table.clear();
            app.status_message = "Screen cleared".to_string();
            return false;
        }
        // Number keys for direct panel focus (only when NOT in Input panel)
        KeyCode::Char('1')
            if key.modifiers.is_empty()
                && app.panel_visibility.tables
                && app.focus_panel != FocusPanel::Input =>
        {
            app.focus_panel = FocusPanel::Tables;
            return false;
        }
        KeyCode::Char('2')
            if key.modifiers.is_empty()
                && app.panel_visibility.results
                && app.focus_panel != FocusPanel::Input =>
        {
            app.focus_panel = FocusPanel::Results;
            return false;
        }
        KeyCode::Char('3')
            if key.modifiers.is_empty()
                && app.panel_visibility.history
                && app.focus_panel != FocusPanel::Input =>
        {
            app.focus_panel = FocusPanel::History;
            return false;
        }
        _ => {}
    }

    // Panel-specific keybindings
    match app.focus_panel {
        FocusPanel::Tables => handle_tables_key(app, key).await,
        FocusPanel::Results => handle_results_key(app, key),
        FocusPanel::History => handle_history_key(app, key),
        FocusPanel::Input => handle_input_key(app, key).await,
    }

    false
}

/// Handle keys when filter input is active
fn handle_filter_key(app: &mut TuiApp, key: event::KeyEvent) -> bool {
    match key.code {
        KeyCode::Enter | KeyCode::Esc => {
            app.tables_browser.filter_active = false;
        }
        KeyCode::Char(c) => {
            app.tables_browser.filter_text.push(c);
            app.tables_browser.apply_filter();
        }
        KeyCode::Backspace => {
            app.tables_browser.filter_text.pop();
            app.tables_browser.apply_filter();
        }
        _ => {}
    }
    false
}

/// Handle keys in Tables panel
async fn handle_tables_key(app: &mut TuiApp, key: event::KeyEvent) {
    let browser = &mut app.tables_browser;

    match key.code {
        KeyCode::Char('j') | KeyCode::Down => {
            let selected = browser.list_state.selected().unwrap_or(0);
            if selected < browser.filtered_indices.len().saturating_sub(1) {
                browser.list_state.select(Some(selected + 1));
            }
        }
        KeyCode::Char('k') | KeyCode::Up => {
            let selected = browser.list_state.selected().unwrap_or(0);
            if selected > 0 {
                browser.list_state.select(Some(selected - 1));
            }
        }
        KeyCode::Char('/') => {
            browser.filter_active = true;
        }
        KeyCode::Enter => {
            // Query selected table
            if let Some(entry) = browser.selected_entry().cloned() {
                app.input = format!("SELECT * FROM {} LIMIT 100", entry.qualified_name);
                app.focus_panel = FocusPanel::Input;
            }
        }
        KeyCode::Char('d') => {
            // Describe selected table
            if let Some(entry) = browser.selected_entry().cloned() {
                app.input = format!("DESCRIBE {}", entry.qualified_name);
                app.focus_panel = FocusPanel::Input;
            }
        }
        KeyCode::Char('g') => {
            browser.list_state.select(Some(0));
        }
        KeyCode::Char('G') => {
            let last = browser.filtered_indices.len().saturating_sub(1);
            browser.list_state.select(Some(last));
        }
        _ => {}
    }
}

/// Handle keys in Results panel
fn handle_results_key(app: &mut TuiApp, key: event::KeyEvent) {
    let results = &mut app.results_table;

    match key.code {
        KeyCode::Char('j') | KeyCode::Down => {
            if results.row_offset < results.rows.len().saturating_sub(1) {
                results.row_offset += 1;
            }
        }
        KeyCode::Char('k') | KeyCode::Up => {
            if results.row_offset > 0 {
                results.row_offset -= 1;
            }
        }
        KeyCode::Char('h') | KeyCode::Left => {
            if results.col_offset > 0 {
                results.col_offset -= 1;
            }
        }
        KeyCode::Char('l') | KeyCode::Right => {
            if results.col_offset < results.columns.len().saturating_sub(1) {
                results.col_offset += 1;
            }
        }
        KeyCode::Char('g') => {
            results.row_offset = 0;
            results.col_offset = 0;
        }
        KeyCode::Char('G') => {
            results.row_offset = results.rows.len().saturating_sub(10);
        }
        KeyCode::PageUp => {
            results.row_offset = results.row_offset.saturating_sub(20);
        }
        KeyCode::PageDown => {
            let max_offset = results.rows.len().saturating_sub(10);
            results.row_offset = (results.row_offset + 20).min(max_offset);
        }
        _ => {}
    }
}

/// Handle keys in History panel
fn handle_history_key(app: &mut TuiApp, key: event::KeyEvent) {
    match key.code {
        KeyCode::Char('j') | KeyCode::Down => {
            let selected = app.history_scroll.selected().unwrap_or(0);
            if selected < app.query_results.len().saturating_sub(1) {
                app.history_scroll.select(Some(selected + 1));
            }
        }
        KeyCode::Char('k') | KeyCode::Up => {
            let selected = app.history_scroll.selected().unwrap_or(0);
            if selected > 0 {
                app.history_scroll.select(Some(selected - 1));
            }
        }
        KeyCode::Enter => {
            // Copy selected query to input
            if let Some(selected) = app.history_scroll.selected() {
                if let Some(result) = app.query_results.get(selected) {
                    app.input = result.query.clone();
                    app.focus_panel = FocusPanel::Input;
                }
            }
        }
        KeyCode::Char('g') => {
            app.history_scroll.select(Some(0));
        }
        KeyCode::Char('G') => {
            let last = app.query_results.len().saturating_sub(1);
            app.history_scroll.select(Some(last));
        }
        _ => {}
    }
}

/// Handle keys in Input panel
async fn handle_input_key(app: &mut TuiApp, key: event::KeyEvent) {
    match key.code {
        KeyCode::Enter => {
            app.execute_query().await;
        }
        KeyCode::Char(c) => {
            app.input.push(c);
            // Reset history navigation when user starts typing
            app.history_index = None;
        }
        KeyCode::Backspace => {
            app.input.pop();
            // Reset history navigation when user edits input
            app.history_index = None;
        }
        KeyCode::Up => {
            app.navigate_history(true);
        }
        KeyCode::Down => {
            app.navigate_history(false);
        }
        _ => {}
    }
}

// =============================================================================
// Layout Calculation (Issue #251)
// =============================================================================

/// Build dynamic layout based on panel visibility
fn build_layout(area: Rect, visibility: &PanelVisibility) -> LayoutAreas {
    // Vertical layout: Header | Main | Input | Status
    let vertical_chunks = Layout::default()
        .direction(Direction::Vertical)
        .margin(0)
        .constraints([
            Constraint::Length(3), // Header
            Constraint::Min(10),   // Main content
            Constraint::Length(3), // Input
            Constraint::Length(3), // Status
        ])
        .split(area);

    let main_area = vertical_chunks[1];

    // Horizontal split: Tables panel (left) | Right side
    let (tables_area, right_area) = if visibility.tables {
        let h_chunks = Layout::default()
            .direction(Direction::Horizontal)
            .constraints([
                Constraint::Percentage(25), // Tables panel
                Constraint::Percentage(75), // Right side
            ])
            .split(main_area);
        (Some(h_chunks[0]), h_chunks[1])
    } else {
        (None, main_area)
    };

    // Right side vertical split: Results (top) | History (bottom)
    let (results_area, history_area) = match (visibility.results, visibility.history) {
        (true, true) => {
            let v_chunks = Layout::default()
                .direction(Direction::Vertical)
                .constraints([
                    Constraint::Percentage(65), // Results
                    Constraint::Percentage(35), // History
                ])
                .split(right_area);
            (Some(v_chunks[0]), Some(v_chunks[1]))
        }
        (true, false) => (Some(right_area), None),
        (false, true) => (None, Some(right_area)),
        (false, false) => (None, None),
    };

    LayoutAreas {
        header: vertical_chunks[0],
        tables: tables_area,
        results: results_area,
        history: history_area,
        input: vertical_chunks[2],
        status: vertical_chunks[3],
    }
}

// =============================================================================
// Panel Rendering Functions (Issue #251)
// =============================================================================

/// Render the Tables browser panel
fn render_tables_panel(f: &mut Frame, area: Rect, app: &mut TuiApp) {
    let is_focused = app.focus_panel == FocusPanel::Tables;
    let border_style = if is_focused {
        Style::default().fg(Color::Cyan)
    } else {
        Style::default().fg(Color::DarkGray)
    };

    // Split for filter input (if active or has text)
    let (filter_area, list_area) =
        if app.tables_browser.filter_active || !app.tables_browser.filter_text.is_empty() {
            let chunks = Layout::default()
                .direction(Direction::Vertical)
                .constraints([Constraint::Length(3), Constraint::Min(1)])
                .split(area);
            (Some(chunks[0]), chunks[1])
        } else {
            (None, area)
        };

    // Render filter input if visible
    if let Some(filter_rect) = filter_area {
        let filter_border = if app.tables_browser.filter_active {
            Style::default().fg(Color::Yellow)
        } else {
            Style::default().fg(Color::DarkGray)
        };
        let filter = Paragraph::new(app.tables_browser.filter_text.as_str())
            .block(
                Block::default()
                    .borders(Borders::ALL)
                    .title("Filter (/)")
                    .border_style(filter_border),
            )
            .style(if app.tables_browser.filter_active {
                Style::default().fg(Color::Yellow)
            } else {
                Style::default()
            });
        f.render_widget(filter, filter_rect);

        // Set cursor in filter input mode
        if app.tables_browser.filter_active {
            f.set_cursor(
                filter_rect.x + app.tables_browser.filter_text.len() as u16 + 1,
                filter_rect.y + 1,
            );
        }
    }

    // Render table list - collect items before borrowing list_state mutably
    let items: Vec<ListItem> = app
        .tables_browser
        .filtered_indices
        .iter()
        .map(|&idx| {
            if let Some(entry) = app.tables_browser.entries.get(idx) {
                ListItem::new(Line::from(vec![
                    Span::styled("+ ", Style::default().fg(Color::Green)),
                    Span::raw(entry.qualified_name.clone()),
                ]))
            } else {
                ListItem::new(Line::from(""))
            }
        })
        .collect();

    let title = format!(
        "Tables [1] ({}/{})",
        app.tables_browser.filtered_indices.len(),
        app.tables_browser.entries.len()
    );

    let list = List::new(items)
        .block(
            Block::default()
                .borders(Borders::ALL)
                .title(title)
                .border_style(border_style),
        )
        .highlight_style(
            Style::default()
                .add_modifier(Modifier::REVERSED)
                .fg(Color::Cyan),
        )
        .highlight_symbol("> ");

    f.render_stateful_widget(list, list_area, &mut app.tables_browser.list_state);
}

/// Render the Query Results panel with Table widget
fn render_results_panel(f: &mut Frame, area: Rect, app: &mut TuiApp) {
    let is_focused = app.focus_panel == FocusPanel::Results;
    let border_style = if is_focused {
        Style::default().fg(Color::Cyan)
    } else {
        Style::default().fg(Color::DarkGray)
    };

    // If no results, show empty state with messages
    if app.results_table.columns.is_empty() {
        // Show messages instead when no query results
        let messages: Vec<ListItem> = app
            .messages
            .iter()
            .enumerate()
            .map(|(i, m)| {
                let content = Line::from(Span::raw(format!("{}: {}", i + 1, m)));
                ListItem::new(content)
            })
            .collect();

        let empty_widget = List::new(messages).block(
            Block::default()
                .borders(Borders::ALL)
                .title("Query Results [2]")
                .border_style(border_style),
        );
        f.render_widget(empty_widget, area);
        return;
    }

    // Calculate visible columns based on available width
    let inner_width = area.width.saturating_sub(4); // Account for borders and highlight symbol
    let visible_cols = app.results_table.visible_columns(inner_width);

    // Build column widths for visible columns - clone to avoid borrow issues
    let column_widths: Vec<u16> = app.results_table.column_widths.clone();

    // Build header row - clone columns to avoid borrow issues and truncate to column width
    let header_cells: Vec<Cell> = app.results_table.columns[visible_cols.clone()]
        .iter()
        .enumerate()
        .map(|(idx, h)| {
            // Get column index in full list for width lookup
            let col_idx = visible_cols.start + idx;
            let col_width = column_widths.get(col_idx).copied().unwrap_or(10) as usize;
            let max_chars = col_width.saturating_sub(2);

            // Truncate header to fit column width
            let truncated = if h.len() > max_chars {
                format!("{}…", &h[..max_chars.saturating_sub(1)])
            } else {
                h.clone()
            };

            Cell::from(truncated).style(
                Style::default()
                    .fg(Color::Yellow)
                    .add_modifier(Modifier::BOLD),
            )
        })
        .collect();
    let header = Row::new(header_cells).height(1);

    // Build data rows with vertical scrolling - clone row data to avoid borrow issues
    let visible_height = area.height.saturating_sub(4) as usize; // Account for borders and header
    let row_offset = app.results_table.row_offset;
    let rows: Vec<Row> = app
        .results_table
        .rows
        .iter()
        .skip(row_offset)
        .take(visible_height)
        .map(|row| {
            let cells: Vec<Cell> = visible_cols
                .clone()
                .enumerate()
                .filter_map(|(_idx, i)| {
                    row.get(i).map(|cell_content| {
                        // Get the column width for truncation
                        let col_width = column_widths.get(i).copied().unwrap_or(10) as usize;
                        // Truncate cell content to fit column width (account for padding)
                        let max_chars = col_width.saturating_sub(2);
                        let truncated = if cell_content.len() > max_chars {
                            format!("{}…", &cell_content[..max_chars.saturating_sub(1)])
                        } else {
                            cell_content.clone()
                        };
                        Cell::from(truncated)
                    })
                })
                .collect();
            Row::new(cells)
        })
        .collect();
    let widths: Vec<Constraint> = visible_cols
        .clone()
        .filter_map(|i| column_widths.get(i).map(|&w| Constraint::Length(w)))
        .collect();

    // Build title with scroll indicators
    let has_left = app.results_table.has_scroll_left();
    let has_right = app.results_table.has_scroll_right(inner_width);
    let num_cols = app.results_table.columns.len();
    let num_rows = app.results_table.rows.len();
    let scroll_hint = if has_left || has_right {
        format!(
            " (cols {}-{}/{}) ",
            visible_cols.start + 1,
            visible_cols.end,
            num_cols
        )
    } else {
        String::new()
    };
    let row_hint = if num_rows > visible_height {
        format!(
            " rows {}-{}/{}",
            row_offset + 1,
            (row_offset + visible_height).min(num_rows),
            num_rows
        )
    } else {
        format!(" {} rows", num_rows)
    };
    let title = format!("Query Results [2]{}{}", scroll_hint, row_hint);

    let table = Table::new(rows)
        .header(header)
        .block(
            Block::default()
                .borders(Borders::ALL)
                .title(title)
                .border_style(border_style),
        )
        .widths(&widths)
        .column_spacing(1) // Add 1 space between columns to prevent overlap
        .highlight_style(Style::default().add_modifier(Modifier::REVERSED))
        .highlight_symbol(">> ");

    f.render_stateful_widget(table, area, &mut app.results_table.table_state);
}

/// Render the Query History panel
fn render_history_panel(f: &mut Frame, area: Rect, app: &mut TuiApp) {
    let is_focused = app.focus_panel == FocusPanel::History;
    let border_style = if is_focused {
        Style::default().fg(Color::Cyan)
    } else {
        Style::default().fg(Color::DarkGray)
    };

    let items: Vec<ListItem> = app
        .query_results
        .iter()
        .map(|result| {
            let status = if result.success { "✓" } else { "✗" };
            let time_str = result
                .execution_time
                .map(|t| format_duration(t))
                .unwrap_or_else(|| "--".to_string());

            let status_style = if result.success {
                Style::default().fg(Color::Green)
            } else {
                Style::default().fg(Color::Red)
            };

            // Truncate query to fit available width (estimate ~60 chars for query text)
            let query_text = if result.query.len() > 60 {
                format!("{}…", &result.query[..59])
            } else {
                result.query.clone()
            };

            // CRITICAL: Build the entire line content as a single Line to prevent wrapping
            // Format: "✓ 7ms SELECT * FROM test_basic.composite_key_table"
            let line = Line::from(vec![
                Span::styled(status, status_style),
                Span::raw(" "),
                Span::styled(time_str, Style::default().fg(Color::Cyan)),
                Span::raw(" "),
                Span::raw(query_text),
            ]);

            ListItem::new(line)
        })
        .collect();

    let title = format!("Query History [3] ({})", app.query_results.len());

    let list = List::new(items)
        .block(
            Block::default()
                .borders(Borders::ALL)
                .title(title)
                .border_style(border_style),
        )
        .highlight_style(
            Style::default()
                .add_modifier(Modifier::BOLD)
                .bg(Color::DarkGray),
        )
        .highlight_symbol("> ");

    f.render_stateful_widget(list, area, &mut app.history_scroll);
}

/// Render the header bar
fn render_header(f: &mut Frame, area: Rect, app: &TuiApp) {
    let keyspace_text = app
        .current_keyspace
        .as_ref()
        .map(|ks| format!("[{}]", ks))
        .unwrap_or_else(|| "[no keyspace]".to_string());

    let header = Paragraph::new(vec![
        Line::from(vec![
            Span::styled(
                "CQLite TUI v0.1.0",
                Style::default()
                    .fg(Color::Cyan)
                    .add_modifier(Modifier::BOLD),
            ),
            Span::raw("  "),
            Span::styled(keyspace_text, Style::default().fg(Color::Yellow)),
            Span::raw("  "),
            Span::styled("F1:Help", Style::default().fg(Color::DarkGray)),
            Span::raw(" "),
            Span::styled("F2-F4:Toggle", Style::default().fg(Color::DarkGray)),
            Span::raw(" "),
            Span::styled("Esc:Exit", Style::default().fg(Color::DarkGray)),
        ]),
        Line::from(vec![
            Span::raw("Database: "),
            Span::styled(
                app.db_path.display().to_string(),
                Style::default().fg(Color::Green),
            ),
        ]),
    ])
    .block(Block::default().borders(Borders::ALL));
    f.render_widget(header, area);
}

/// Render the input area
fn render_input(f: &mut Frame, area: Rect, app: &TuiApp) {
    let is_focused = app.focus_panel == FocusPanel::Input;
    let border_style = if is_focused {
        Style::default().fg(Color::Cyan)
    } else {
        Style::default().fg(Color::DarkGray)
    };

    let input = Paragraph::new(app.input.as_str())
        .style(if is_focused {
            Style::default().fg(Color::Yellow)
        } else {
            Style::default()
        })
        .block(
            Block::default()
                .borders(Borders::ALL)
                .title("CQL> ")
                .border_style(border_style),
        );
    f.render_widget(input, area);

    // Set cursor position when input is focused
    if is_focused && !app.tables_browser.filter_active {
        f.set_cursor(area.x + app.input.len() as u16 + 1, area.y + 1);
    }
}

/// Render the status bar
fn render_status(f: &mut Frame, area: Rect, app: &TuiApp) {
    let (health_text, health_color) = match app.status_metrics.as_ref() {
        Some(metrics) => match metrics.health {
            HealthIndicator::Ok => ("OK", Color::Green),
            HealthIndicator::Warning => ("WARN", Color::Yellow),
            HealthIndicator::Error => ("ERR", Color::Red),
        },
        None => ("--", Color::DarkGray),
    };

    let memory_text = app
        .status_metrics
        .as_ref()
        .map(|m| m.format_memory())
        .unwrap_or_else(|| "--".to_string());

    let data_text = app
        .status_metrics
        .as_ref()
        .map(|m| m.format_data())
        .unwrap_or_else(|| "--".to_string());

    // Show focused panel in mode
    let mode_text = match app.focus_panel {
        FocusPanel::Tables => "TABLES",
        FocusPanel::Results => "RESULTS",
        FocusPanel::History => "HISTORY",
        FocusPanel::Input => "INPUT",
    };

    let status_line = Line::from(vec![
        Span::raw("Health: "),
        Span::styled(health_text, Style::default().fg(health_color)),
        Span::raw(" | Mem: "),
        Span::styled(&memory_text, Style::default().fg(Color::Cyan)),
        Span::raw(" | Data: "),
        Span::styled(&data_text, Style::default().fg(Color::Cyan)),
        Span::raw(" | Status: "),
        Span::styled(&app.status_message, Style::default().fg(Color::Green)),
        Span::raw(" | Mode: "),
        Span::styled(mode_text, Style::default().fg(Color::Cyan)),
    ]);

    let status = Paragraph::new(status_line).block(Block::default().borders(Borders::ALL));
    f.render_widget(status, area);
}

/// Draw the TUI interface
fn ui(f: &mut Frame, app: &mut TuiApp) {
    if app.show_help {
        draw_help(f);
        return;
    }

    // Build dynamic layout based on panel visibility
    let layout = build_layout(f.size(), &app.panel_visibility);

    // Render header
    render_header(f, layout.header, app);

    // Render visible panels
    if let Some(tables_area) = layout.tables {
        render_tables_panel(f, tables_area, app);
    }

    if let Some(results_area) = layout.results {
        render_results_panel(f, results_area, app);
    }

    if let Some(history_area) = layout.history {
        render_history_panel(f, history_area, app);
    }

    // If no panels are visible in main area, show a message
    if layout.tables.is_none() && layout.results.is_none() && layout.history.is_none() {
        // This shouldn't happen normally, but handle gracefully
        let main_area = Layout::default()
            .direction(Direction::Vertical)
            .constraints([
                Constraint::Length(3),
                Constraint::Min(1),
                Constraint::Length(3),
                Constraint::Length(3),
            ])
            .split(f.size())[1];

        let msg = Paragraph::new("Press F2/F3/F4 to show panels, or F5 to reset layout")
            .block(Block::default().borders(Borders::ALL).title("No Panels"))
            .style(Style::default().fg(Color::DarkGray));
        f.render_widget(msg, main_area);
    }

    // Render input area
    render_input(f, layout.input, app);

    // Render status bar
    render_status(f, layout.status, app);
}

/// Draw the help screen
fn draw_help(f: &mut Frame) {
    let help_text = vec![
        Line::from(Span::styled(
            "CQLite TUI Help (Issue #251)",
            Style::default()
                .fg(Color::Cyan)
                .add_modifier(Modifier::BOLD),
        )),
        Line::from(""),
        Line::from(Span::styled(
            "Global Commands:",
            Style::default().add_modifier(Modifier::BOLD),
        )),
        Line::from("  F1          Toggle this help screen"),
        Line::from("  F2          Toggle Tables panel"),
        Line::from("  F3          Toggle Results panel"),
        Line::from("  F4          Toggle History panel"),
        Line::from("  F5          Reset layout (show all panels)"),
        Line::from("  Tab         Cycle focus to next panel"),
        Line::from("  Shift+Tab   Cycle focus to previous panel"),
        Line::from("  1/2/3       Jump directly to panel"),
        Line::from("  Esc         Exit application"),
        Line::from("  Ctrl+C      Quit immediately"),
        Line::from("  Ctrl+L      Clear screen and history"),
        Line::from(""),
        Line::from(Span::styled(
            "Tables Panel [1]:",
            Style::default().add_modifier(Modifier::BOLD),
        )),
        Line::from("  j/k, Up/Down  Navigate tables"),
        Line::from("  /             Open filter input"),
        Line::from("  Enter         Query selected table"),
        Line::from("  d             Describe selected table"),
        Line::from("  g/G           Jump to first/last table"),
        Line::from(""),
        Line::from(Span::styled(
            "Results Panel [2]:",
            Style::default().add_modifier(Modifier::BOLD),
        )),
        Line::from("  j/k, Up/Down  Scroll rows"),
        Line::from("  h/l, Left/Right  Scroll columns (horizontal)"),
        Line::from("  g/G           Jump to first/last row"),
        Line::from("  PgUp/PgDn     Page up/down"),
        Line::from(""),
        Line::from(Span::styled(
            "History Panel [3]:",
            Style::default().add_modifier(Modifier::BOLD),
        )),
        Line::from("  j/k, Up/Down  Navigate history"),
        Line::from("  Enter         Copy query to input"),
        Line::from("  g/G           Jump to first/last entry"),
        Line::from(""),
        Line::from(Span::styled(
            "Input Panel:",
            Style::default().add_modifier(Modifier::BOLD),
        )),
        Line::from("  Enter         Execute current query"),
        Line::from("  Up/Down       Navigate command history"),
        Line::from("  Backspace     Delete character"),
        Line::from(""),
        Line::from(Span::styled(
            "Press any key to close this help",
            Style::default().fg(Color::DarkGray),
        )),
    ];

    let help_paragraph = Paragraph::new(help_text)
        .block(
            Block::default()
                .borders(Borders::ALL)
                .title("Help - Press any key to close")
                .border_style(Style::default().fg(Color::Yellow)),
        )
        .wrap(Wrap { trim: true });

    let area = centered_rect(85, 95, f.size());
    f.render_widget(help_paragraph, area);
}

/// Create a centered rectangle
fn centered_rect(percent_x: u16, percent_y: u16, r: Rect) -> Rect {
    let popup_layout = Layout::default()
        .direction(Direction::Vertical)
        .constraints([
            Constraint::Percentage((100 - percent_y) / 2),
            Constraint::Percentage(percent_y),
            Constraint::Percentage((100 - percent_y) / 2),
        ])
        .split(r);

    Layout::default()
        .direction(Direction::Horizontal)
        .constraints([
            Constraint::Percentage((100 - percent_x) / 2),
            Constraint::Percentage(percent_x),
            Constraint::Percentage((100 - percent_x) / 2),
        ])
        .split(popup_layout[1])[1]
}

/// Format a Duration for display with smart unit selection
///
/// - < 1ms: Display as "XXXμs" (microseconds)
/// - 1-999ms: Display as "X.Xms" (milliseconds with 1 decimal)
/// - >= 1000ms: Display as "X.Xs" (seconds with 1 decimal)
///
/// Examples:
/// - 450μs -> "450μs"
/// - 1.2ms -> "1.2ms"
/// - 7.0ms -> "7.0ms"
/// - 1500ms -> "1.5s"
fn format_duration(duration: Duration) -> String {
    let micros = duration.as_micros();

    if micros < 1_000 {
        // Sub-millisecond: show microseconds
        format!("{}μs", micros)
    } else if micros < 1_000_000 {
        // 1-999ms: show milliseconds with 1 decimal place
        format!("{:.1}ms", micros as f64 / 1_000.0)
    } else {
        // >= 1 second: show seconds with 1 decimal place
        format!("{:.1}s", micros as f64 / 1_000_000.0)
    }
}

/// Extract table name from SSTable directory name
///
/// Expected format: tablename-uuid
/// Returns the table name part before the first dash.
fn extract_table_name(dir_name: &str) -> Option<String> {
    if let Some(dash_pos) = dir_name.find('-') {
        let table_part = &dir_name[..dash_pos];
        if !table_part.is_empty() && table_part.chars().all(|c| c.is_alphanumeric() || c == '_') {
            return Some(table_part.to_string());
        }
    }
    None
}

// =============================================================================
// Unit Tests
// =============================================================================

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

    // -------------------------------------------------------------------------
    // FocusPanel Tests
    // -------------------------------------------------------------------------

    #[test]
    fn test_focus_panel_next_all_visible() {
        let visibility = PanelVisibility {
            tables: true,
            results: true,
            history: true,
        };

        // Cycle through all panels
        assert_eq!(FocusPanel::Tables.next(&visibility), FocusPanel::Results);
        assert_eq!(FocusPanel::Results.next(&visibility), FocusPanel::History);
        assert_eq!(FocusPanel::History.next(&visibility), FocusPanel::Input);
        assert_eq!(FocusPanel::Input.next(&visibility), FocusPanel::Tables);
    }

    #[test]
    fn test_focus_panel_prev_all_visible() {
        let visibility = PanelVisibility {
            tables: true,
            results: true,
            history: true,
        };

        // Cycle backwards through all panels
        assert_eq!(FocusPanel::Tables.prev(&visibility), FocusPanel::Input);
        assert_eq!(FocusPanel::Input.prev(&visibility), FocusPanel::History);
        assert_eq!(FocusPanel::History.prev(&visibility), FocusPanel::Results);
        assert_eq!(FocusPanel::Results.prev(&visibility), FocusPanel::Tables);
    }

    #[test]
    fn test_focus_panel_next_skips_hidden_tables() {
        let visibility = PanelVisibility {
            tables: false,
            results: true,
            history: true,
        };

        // Should skip Tables and go to Results
        assert_eq!(FocusPanel::Input.next(&visibility), FocusPanel::Results);
        assert_eq!(FocusPanel::Results.next(&visibility), FocusPanel::History);
        assert_eq!(FocusPanel::History.next(&visibility), FocusPanel::Input);
    }

    #[test]
    fn test_focus_panel_next_skips_hidden_results() {
        let visibility = PanelVisibility {
            tables: true,
            results: false,
            history: true,
        };

        // Should skip Results
        assert_eq!(FocusPanel::Tables.next(&visibility), FocusPanel::History);
        assert_eq!(FocusPanel::History.next(&visibility), FocusPanel::Input);
        assert_eq!(FocusPanel::Input.next(&visibility), FocusPanel::Tables);
    }

    #[test]
    fn test_focus_panel_next_skips_hidden_history() {
        let visibility = PanelVisibility {
            tables: true,
            results: true,
            history: false,
        };

        // Should skip History
        assert_eq!(FocusPanel::Results.next(&visibility), FocusPanel::Input);
        assert_eq!(FocusPanel::Input.next(&visibility), FocusPanel::Tables);
        assert_eq!(FocusPanel::Tables.next(&visibility), FocusPanel::Results);
    }

    #[test]
    fn test_focus_panel_next_only_input_visible() {
        let visibility = PanelVisibility {
            tables: false,
            results: false,
            history: false,
        };

        // All panels hidden - should cycle only on Input
        assert_eq!(FocusPanel::Input.next(&visibility), FocusPanel::Input);
        assert_eq!(FocusPanel::Tables.next(&visibility), FocusPanel::Input);
        assert_eq!(FocusPanel::Results.next(&visibility), FocusPanel::Input);
        assert_eq!(FocusPanel::History.next(&visibility), FocusPanel::Input);
    }

    #[test]
    fn test_focus_panel_prev_skips_hidden_panels() {
        let visibility = PanelVisibility {
            tables: false,
            results: true,
            history: false,
        };

        // Only Results and Input visible
        assert_eq!(FocusPanel::Results.prev(&visibility), FocusPanel::Input);
        assert_eq!(FocusPanel::Input.prev(&visibility), FocusPanel::Results);
    }

    #[test]
    fn test_focus_panel_input_always_reachable() {
        // Input is always reachable regardless of visibility
        let visibility = PanelVisibility {
            tables: false,
            results: false,
            history: false,
        };

        // Start from any panel, should eventually reach Input
        let mut current = FocusPanel::Tables;
        for _ in 0..5 {
            current = current.next(&visibility);
        }
        assert_eq!(current, FocusPanel::Input);
    }

    // -------------------------------------------------------------------------
    // TablesBrowserState Filter Tests
    // -------------------------------------------------------------------------

    #[test]
    fn test_apply_filter_empty_shows_all() {
        let mut state = TablesBrowserState::default();
        state.entries = vec![
            TableEntry {
                keyspace: "ks1".to_string(),
                name: "table1".to_string(),
                qualified_name: "ks1.table1".to_string(),
            },
            TableEntry {
                keyspace: "ks2".to_string(),
                name: "table2".to_string(),
                qualified_name: "ks2.table2".to_string(),
            },
            TableEntry {
                keyspace: "ks3".to_string(),
                name: "users".to_string(),
                qualified_name: "ks3.users".to_string(),
            },
        ];

        state.filter_text = String::new();
        state.apply_filter();

        // All entries should be visible
        assert_eq!(state.filtered_indices, vec![0, 1, 2]);
    }

    #[test]
    fn test_apply_filter_matches_some() {
        let mut state = TablesBrowserState::default();
        state.entries = vec![
            TableEntry {
                keyspace: "ks1".to_string(),
                name: "table1".to_string(),
                qualified_name: "ks1.table1".to_string(),
            },
            TableEntry {
                keyspace: "ks2".to_string(),
                name: "table2".to_string(),
                qualified_name: "ks2.table2".to_string(),
            },
            TableEntry {
                keyspace: "ks3".to_string(),
                name: "users".to_string(),
                qualified_name: "ks3.users".to_string(),
            },
        ];

        state.filter_text = "table".to_string();
        state.apply_filter();

        // Only entries containing "table" should be visible
        assert_eq!(state.filtered_indices, vec![0, 1]);
    }

    #[test]
    fn test_apply_filter_matches_none() {
        let mut state = TablesBrowserState::default();
        state.entries = vec![
            TableEntry {
                keyspace: "ks1".to_string(),
                name: "table1".to_string(),
                qualified_name: "ks1.table1".to_string(),
            },
            TableEntry {
                keyspace: "ks2".to_string(),
                name: "table2".to_string(),
                qualified_name: "ks2.table2".to_string(),
            },
        ];

        state.filter_text = "nonexistent".to_string();
        state.apply_filter();

        // No entries should match
        assert_eq!(state.filtered_indices, Vec::<usize>::new());
    }

    #[test]
    fn test_apply_filter_case_insensitive() {
        let mut state = TablesBrowserState::default();
        state.entries = vec![
            TableEntry {
                keyspace: "TestKS".to_string(),
                name: "Users".to_string(),
                qualified_name: "TestKS.Users".to_string(),
            },
            TableEntry {
                keyspace: "prodks".to_string(),
                name: "products".to_string(),
                qualified_name: "prodks.products".to_string(),
            },
        ];

        state.filter_text = "USERS".to_string();
        state.apply_filter();

        // Case-insensitive match
        assert_eq!(state.filtered_indices, vec![0]);
    }

    #[test]
    fn test_apply_filter_resets_selection_when_out_of_bounds() {
        let mut state = TablesBrowserState::default();
        state.entries = vec![
            TableEntry {
                keyspace: "ks1".to_string(),
                name: "table1".to_string(),
                qualified_name: "ks1.table1".to_string(),
            },
            TableEntry {
                keyspace: "ks2".to_string(),
                name: "table2".to_string(),
                qualified_name: "ks2.table2".to_string(),
            },
            TableEntry {
                keyspace: "ks3".to_string(),
                name: "users".to_string(),
                qualified_name: "ks3.users".to_string(),
            },
        ];

        // Select the last item
        state.filtered_indices = vec![0, 1, 2];
        state.list_state.select(Some(2));

        // Apply filter that removes selected item
        state.filter_text = "table".to_string();
        state.apply_filter();

        // Selection should be reset to first item
        assert_eq!(state.list_state.selected(), Some(0));
        assert_eq!(state.filtered_indices, vec![0, 1]);
    }

    #[test]
    fn test_apply_filter_resets_selection_when_empty() {
        let mut state = TablesBrowserState::default();
        state.entries = vec![TableEntry {
            keyspace: "ks1".to_string(),
            name: "table1".to_string(),
            qualified_name: "ks1.table1".to_string(),
        }];

        state.filtered_indices = vec![0];
        state.list_state.select(Some(0));

        // Apply filter that matches nothing
        state.filter_text = "nonexistent".to_string();
        state.apply_filter();

        // Selection should be cleared
        assert_eq!(state.list_state.selected(), None);
        assert_eq!(state.filtered_indices, Vec::<usize>::new());
    }

    // -------------------------------------------------------------------------
    // ResultsTableState Tests
    // -------------------------------------------------------------------------

    #[test]
    fn test_calculate_widths_empty_columns() {
        let mut state = ResultsTableState::default();
        state.calculate_widths();

        assert_eq!(state.column_widths, Vec::<u16>::new());
    }

    #[test]
    fn test_calculate_widths_headers_only() {
        let mut state = ResultsTableState::default();
        state.columns = vec!["id".to_string(), "name".to_string(), "email".to_string()];
        state.calculate_widths();

        // Widths should be header length + 2 (padding)
        // "id" (2) + 2 = 4, "name" (4) + 2 = 6, "email" (5) + 2 = 7
        assert_eq!(state.column_widths, vec![4, 6, 7]);
    }

    #[test]
    fn test_calculate_widths_with_data() {
        let mut state = ResultsTableState::default();
        state.columns = vec!["id".to_string(), "name".to_string()];
        state.rows = vec![
            vec!["1".to_string(), "Alice".to_string()],
            vec!["2".to_string(), "BobTheBuilder".to_string()],
        ];
        state.calculate_widths();

        // id column: max(2, 1) + 2 = 4
        // name column: max(4, 13) + 2 = 15
        assert_eq!(state.column_widths, vec![4, 15]);
    }

    #[test]
    fn test_calculate_widths_caps_at_40() {
        let mut state = ResultsTableState::default();
        state.columns = vec!["long_column".to_string()];
        state.rows = vec![vec!["a".repeat(100)]];
        state.calculate_widths();

        // Should cap at 40
        assert_eq!(state.column_widths, vec![40]);
    }

    #[test]
    fn test_calculate_widths_samples_first_100_rows() {
        let mut state = ResultsTableState::default();
        state.columns = vec!["data".to_string()];

        // Create 150 rows, with row 101 having the longest content
        let mut rows = Vec::new();
        for i in 0..150 {
            if i == 101 {
                rows.push(vec!["very_long_content_here".to_string()]);
            } else {
                rows.push(vec!["x".to_string()]);
            }
        }
        state.rows = rows;
        state.calculate_widths();

        // Should only sample first 100, so won't see row 101's long content
        // Width should be max(4, 1) + 2 = 6
        assert_eq!(state.column_widths, vec![6]);
    }

    #[test]
    fn test_visible_columns_empty() {
        let state = ResultsTableState::default();
        let visible = state.visible_columns(100);

        assert_eq!(visible, 0..0);
    }

    #[test]
    fn test_visible_columns_all_fit() {
        let mut state = ResultsTableState::default();
        state.columns = vec!["a".to_string(), "b".to_string(), "c".to_string()];
        state.column_widths = vec![10, 10, 10];
        state.col_offset = 0;

        let visible = state.visible_columns(50);

        // All columns fit
        assert_eq!(visible, 0..3);
    }

    #[test]
    fn test_visible_columns_with_offset() {
        let mut state = ResultsTableState::default();
        state.columns = vec!["a".to_string(), "b".to_string(), "c".to_string()];
        state.column_widths = vec![10, 10, 10];
        state.col_offset = 1;

        let visible = state.visible_columns(50);

        // Should start from offset 1
        assert_eq!(visible, 1..3);
    }

    #[test]
    fn test_visible_columns_partial_fit() {
        let mut state = ResultsTableState::default();
        state.columns = vec!["a".to_string(), "b".to_string(), "c".to_string()];
        state.column_widths = vec![15, 15, 15];
        state.col_offset = 0;

        let visible = state.visible_columns(25);

        // Only first 2 columns fit (15 + 15 = 30 > 25, but 15 < 25)
        assert_eq!(visible, 0..1);
    }

    #[test]
    fn test_visible_columns_clamps_offset() {
        let mut state = ResultsTableState::default();
        state.columns = vec!["a".to_string(), "b".to_string()];
        state.column_widths = vec![10, 10];
        state.col_offset = 100; // Beyond bounds

        let visible = state.visible_columns(50);

        // Should clamp to last valid column
        assert_eq!(visible, 1..2);
    }

    #[test]
    fn test_has_scroll_left() {
        let mut state = ResultsTableState::default();

        state.col_offset = 0;
        assert!(!state.has_scroll_left());

        state.col_offset = 1;
        assert!(state.has_scroll_left());

        state.col_offset = 5;
        assert!(state.has_scroll_left());
    }

    #[test]
    fn test_has_scroll_right() {
        let mut state = ResultsTableState::default();
        state.columns = vec!["a".to_string(), "b".to_string(), "c".to_string()];
        state.column_widths = vec![20, 20, 20];
        state.col_offset = 0;

        // With 30 available width, only first 2 columns visible
        assert!(state.has_scroll_right(30));

        // With 100 available width, all columns visible
        assert!(!state.has_scroll_right(100));
    }

    #[test]
    fn test_has_scroll_right_at_end() {
        let mut state = ResultsTableState::default();
        state.columns = vec!["a".to_string(), "b".to_string()];
        state.column_widths = vec![10, 10];
        state.col_offset = 1; // At last column

        // At last column, no scroll right
        assert!(!state.has_scroll_right(100));
    }

    #[test]
    fn test_clear() {
        let mut state = ResultsTableState::default();
        state.columns = vec!["a".to_string(), "b".to_string()];
        state.rows = vec![vec!["1".to_string(), "2".to_string()]];
        state.row_offset = 5;
        state.col_offset = 2;
        state.selected_row = Some(3);
        state.column_widths = vec![10, 20];

        state.clear();

        assert!(state.columns.is_empty());
        assert!(state.rows.is_empty());
        assert_eq!(state.row_offset, 0);
        assert_eq!(state.col_offset, 0);
        assert_eq!(state.selected_row, None);
        assert!(state.column_widths.is_empty());
    }

    // -------------------------------------------------------------------------
    // PanelVisibility Tests
    // -------------------------------------------------------------------------

    #[test]
    fn test_panel_visibility_default() {
        let visibility = PanelVisibility::default();

        assert!(visibility.tables);
        assert!(visibility.results);
        assert!(visibility.history);
    }

    #[test]
    fn test_panel_visibility_reset() {
        let mut visibility = PanelVisibility {
            tables: false,
            results: false,
            history: false,
        };

        visibility.reset();

        assert!(visibility.tables);
        assert!(visibility.results);
        assert!(visibility.history);
    }

    #[test]
    fn test_panel_visibility_reset_restores_default() {
        let mut visibility = PanelVisibility {
            tables: true,
            results: false,
            history: true,
        };

        visibility.reset();

        let default = PanelVisibility::default();
        assert_eq!(visibility.tables, default.tables);
        assert_eq!(visibility.results, default.results);
        assert_eq!(visibility.history, default.history);
    }

    // -------------------------------------------------------------------------
    // format_duration Tests (Microsecond Display Support)
    // -------------------------------------------------------------------------

    #[test]
    fn test_format_duration_microseconds() {
        // Sub-millisecond times should display in microseconds
        assert_eq!(format_duration(Duration::from_micros(0)), "0μs");
        assert_eq!(format_duration(Duration::from_micros(1)), "1μs");
        assert_eq!(format_duration(Duration::from_micros(450)), "450μs");
        assert_eq!(format_duration(Duration::from_micros(999)), "999μs");
    }

    #[test]
    fn test_format_duration_milliseconds() {
        // 1-999ms should display with 1 decimal place
        assert_eq!(format_duration(Duration::from_micros(1_000)), "1.0ms");
        assert_eq!(format_duration(Duration::from_micros(1_200)), "1.2ms");
        assert_eq!(format_duration(Duration::from_micros(7_000)), "7.0ms");
        assert_eq!(format_duration(Duration::from_micros(74_000)), "74.0ms");
        assert_eq!(format_duration(Duration::from_micros(123_456)), "123.5ms");
        assert_eq!(format_duration(Duration::from_micros(999_999)), "1000.0ms");
    }

    #[test]
    fn test_format_duration_seconds() {
        // >= 1000ms should display as seconds with 1 decimal place
        assert_eq!(format_duration(Duration::from_micros(1_000_000)), "1.0s");
        assert_eq!(format_duration(Duration::from_micros(1_500_000)), "1.5s");
        assert_eq!(format_duration(Duration::from_micros(2_750_000)), "2.8s");
        assert_eq!(format_duration(Duration::from_micros(10_000_000)), "10.0s");
        assert_eq!(
            format_duration(Duration::from_micros(123_456_789)),
            "123.5s"
        );
    }

    #[test]
    fn test_format_duration_boundary_cases() {
        // Test exact boundaries between units
        assert_eq!(format_duration(Duration::from_nanos(999_999)), "999μs");
        assert_eq!(format_duration(Duration::from_nanos(1_000_000)), "1.0ms");
        assert_eq!(
            format_duration(Duration::from_nanos(999_999_999)),
            "1000.0ms"
        );
        assert_eq!(format_duration(Duration::from_nanos(1_000_000_000)), "1.0s");
    }

    #[test]
    fn test_format_duration_typical_query_times() {
        // Test typical query execution times seen in the wild
        assert_eq!(format_duration(Duration::from_micros(500)), "500μs"); // Fast indexed lookup
        assert_eq!(format_duration(Duration::from_micros(3_500)), "3.5ms"); // Normal query
        assert_eq!(format_duration(Duration::from_micros(25_000)), "25.0ms"); // Slower query
        assert_eq!(format_duration(Duration::from_micros(150_000)), "150.0ms"); // Complex query
    }

    // -------------------------------------------------------------------------
    // History Navigation Tests
    // -------------------------------------------------------------------------

    #[test]
    fn test_navigate_history_empty() {
        // Create a minimal TuiApp for testing history navigation
        let mut app_state = create_test_app_state();

        // Navigating empty history should do nothing
        app_state.navigate_history(true);
        assert_eq!(app_state.input, "");
        assert_eq!(app_state.history_index, None);
    }

    #[test]
    fn test_navigate_history_up_from_fresh() {
        let mut app_state = create_test_app_state();

        // Add some history
        app_state.history.push("SELECT * FROM users".to_string());
        app_state.history.push("SELECT * FROM orders".to_string());
        app_state.history.push("SELECT * FROM products".to_string());

        // Press Up once - should show most recent command
        app_state.navigate_history(true);
        assert_eq!(app_state.input, "SELECT * FROM products");
        assert_eq!(app_state.history_index, Some(2));

        // Press Up again - should show previous command
        app_state.navigate_history(true);
        assert_eq!(app_state.input, "SELECT * FROM orders");
        assert_eq!(app_state.history_index, Some(1));

        // Press Up again - should show oldest command
        app_state.navigate_history(true);
        assert_eq!(app_state.input, "SELECT * FROM users");
        assert_eq!(app_state.history_index, Some(0));

        // Press Up again - should stay at oldest
        app_state.navigate_history(true);
        assert_eq!(app_state.input, "SELECT * FROM users");
        assert_eq!(app_state.history_index, Some(0));
    }

    #[test]
    fn test_navigate_history_down() {
        let mut app_state = create_test_app_state();

        // Add history
        app_state.history.push("command1".to_string());
        app_state.history.push("command2".to_string());
        app_state.history.push("command3".to_string());

        // Navigate to middle of history
        app_state.navigate_history(true);
        app_state.navigate_history(true);
        assert_eq!(app_state.history_index, Some(1));
        assert_eq!(app_state.input, "command2");

        // Press Down - should go forward
        app_state.navigate_history(false);
        assert_eq!(app_state.input, "command3");
        assert_eq!(app_state.history_index, Some(2));

        // Press Down again - should clear input and reset
        app_state.navigate_history(false);
        assert_eq!(app_state.input, "");
        assert_eq!(app_state.history_index, None);

        // Press Down when already at end - should do nothing
        app_state.navigate_history(false);
        assert_eq!(app_state.input, "");
        assert_eq!(app_state.history_index, None);
    }

    #[test]
    fn test_navigate_history_cycle() {
        let mut app_state = create_test_app_state();

        // Add history
        app_state.history.push("first".to_string());
        app_state.history.push("second".to_string());

        // Go up to oldest
        app_state.navigate_history(true);
        app_state.navigate_history(true);
        assert_eq!(app_state.input, "first");

        // Go down to newest
        app_state.navigate_history(false);
        assert_eq!(app_state.input, "second");

        // Go down past end - should clear
        app_state.navigate_history(false);
        assert_eq!(app_state.input, "");
        assert_eq!(app_state.history_index, None);

        // Can navigate up again from fresh state
        app_state.navigate_history(true);
        assert_eq!(app_state.input, "second");
        assert_eq!(app_state.history_index, Some(1));
    }

    /// Helper struct for testing history navigation without a full TuiApp
    /// This allows us to test the navigate_history logic in isolation
    struct TestHistoryState {
        input: String,
        history: Vec<String>,
        history_index: Option<usize>,
    }

    impl TestHistoryState {
        fn new() -> Self {
            Self {
                input: String::new(),
                history: Vec::new(),
                history_index: None,
            }
        }

        /// Navigate history (same logic as TuiApp::navigate_history)
        fn navigate_history(&mut self, up: bool) {
            if self.history.is_empty() {
                return;
            }

            if up {
                let index = match self.history_index {
                    None => self.history.len() - 1,
                    Some(i) if i > 0 => i - 1,
                    Some(_) => return,
                };
                self.history_index = Some(index);
                self.input = self.history[index].clone();
            } else {
                match self.history_index {
                    None => return,
                    Some(i) if i < self.history.len() - 1 => {
                        self.history_index = Some(i + 1);
                        self.input = self.history[i + 1].clone();
                    }
                    Some(_) => {
                        self.history_index = None;
                        self.input.clear();
                    }
                }
            }
        }
    }

    /// Helper function to create a minimal test state for history navigation
    fn create_test_app_state() -> TestHistoryState {
        TestHistoryState::new()
    }

    // -------------------------------------------------------------------------
    // extract_table_name Tests (Issue #251)
    // -------------------------------------------------------------------------

    #[test]
    fn test_extract_table_name_valid() {
        assert_eq!(
            extract_table_name("users-3b7a9d8c"),
            Some("users".to_string())
        );
        assert_eq!(
            extract_table_name("test_table-abc123"),
            Some("test_table".to_string())
        );
        assert_eq!(
            extract_table_name("MyTable123-uuid"),
            Some("MyTable123".to_string())
        );
    }

    #[test]
    fn test_extract_table_name_invalid() {
        // No dash
        assert_eq!(extract_table_name("users"), None);
        // Empty before dash
        assert_eq!(extract_table_name("-uuid"), None);
        // Special characters
        assert_eq!(extract_table_name("table.name-uuid"), None);
        assert_eq!(
            extract_table_name("table-name-uuid"),
            Some("table".to_string())
        ); // Takes first part before first dash
    }

    #[test]
    fn test_extract_table_name_edge_cases() {
        // Multiple dashes - should extract first part
        assert_eq!(
            extract_table_name("my-table-uuid-1234"),
            Some("my".to_string())
        );
        // Just dash
        assert_eq!(extract_table_name("-"), None);
        // Empty string
        assert_eq!(extract_table_name(""), None);
    }
}