// src/components/handlers/buffer_list.rs

use crate::config::colors::themes::Theme;
use crate::state::app::state::AppState;
use ratatui::{
    layout::{Alignment, Rect},
    style::{Modifier, Style, Stylize},
    text::{Line, Span},
    widgets::Paragraph, // Removed Block and Borders
    Frame,
};
use unicode_width::UnicodeWidthStr;

pub fn render_buffer_list(
    f: &mut Frame,
    area: Rect, // Still 1 line high
    theme: &Theme,
    app_state: &AppState,
) {
    let mut current_buffer_name = "*scratch*"; // Default

    // Determine the active buffer name based on UI state
    if app_state.ui.show_intro {
        current_buffer_name = "Intro";
    } else if app_state.ui.show_register {
        current_buffer_name = "Register";
    } else if app_state.ui.show_login {
        current_buffer_name = "Login";
    } else if app_state.ui.show_admin {
        current_buffer_name = "Admin Panel";
    } else if app_state.ui.show_form {
        current_buffer_name = "Data Form";
    }
    // Add more conditions if other views exist

    // --- Style Definitions ---
    // Use Powerline symbols if available, otherwise fallback
    // Ensure your terminal font supports these for the best look!
    const RIGHT_SEPARATOR: &str = ""; // U+E0B0
    // const RIGHT_SEPARATOR: &str = ">"; // Fallback
    const LEFT_SEPARATOR: &str = ""; // U+E0B2
    // const LEFT_SEPARATOR: &str = "<"; // Fallback

    let active_style = Style::default()
        .fg(theme.bg) // Text on active background
        .bg(theme.highlight); // Active background

    let separator_style_active_to_inactive = Style::default()
        .fg(theme.highlight) // Separator color matches the background it comes from
        .bg(theme.bg); // Background matches the area it points into

    let inactive_style = Style::default()
        .fg(theme.fg) // Default text color
        .bg(theme.bg); // Default background

    // --- Create Spans ---
    let buffer_text = format!(" {} ", current_buffer_name); // Add padding

    // Span 1: Left edge (no separator needed if it's the first element)
    // If you had multiple buffers, the *first* one wouldn't have a left separator.
    // let left_sep = Span::raw(""); // Example for first buffer

    // Span 2: The active buffer text
    let buffer_span = Span::styled(buffer_text.clone(), active_style);

    // Span 3: The right separator pointing away from the active buffer
    let right_sep = Span::styled(
        RIGHT_SEPARATOR,
        separator_style_active_to_inactive,
    );

    // Span 4: Filler for the rest of the line
    let text_width = UnicodeWidthStr::width(buffer_text.as_str());   
    // Account for the width of the separator character (usually 1)
    let separator_width = UnicodeWidthStr::width(RIGHT_SEPARATOR);
    let total_used_width = (text_width + separator_width) as u16;
    let remaining_width = area.width.saturating_sub(total_used_width);
    let filler_span = Span::styled(
        " ".repeat(remaining_width as usize),
        inactive_style, // Filler uses inactive style
    );

    // --- Combine into Line ---
    // Order: Buffer Text -> Right Separator -> Filler
    // (If multiple buffers: LeftSep -> Text -> RightSep -> LeftSep -> Text -> ...)
    let buffer_line = Line::from(vec![buffer_span, right_sep, filler_span]);

    // --- Render ---
    let paragraph = Paragraph::new(buffer_line).alignment(Alignment::Left);

    f.render_widget(paragraph, area);
}