use ratatui::{
    layout::{Alignment, Constraint, Direction, Layout, Rect},
    style::{Color, Modifier, Style},
    text::{Line, Span},
    widgets::{Block, Borders, Paragraph},
    Frame,
};
use crate::app::App;
use crate::utils::format_timestamp;

pub fn render(f: &mut Frame, area: Rect, app: &App) {
    if let Some(chat) = app.get_selected_chat() {
        let message_chunks = Layout::default()
            .direction(Direction::Vertical)
            .constraints([
                Constraint::Length(3), // Chat header
                Constraint::Min(0),    // Messages
                Constraint::Length(3), // Input box
            ])
            .split(area);

        // Chat header
        let header = Paragraph::new(format!("👤 {}", chat.title))
            .block(Block::default().borders(Borders::ALL))
            .style(
                Style::default()
                    .fg(Color::Cyan)
                    .add_modifier(Modifier::BOLD),
            );
        f.render_widget(header, message_chunks[0]);

        // Messages
        let mut lines: Vec<Line> = Vec::new();

        for msg in &app.current_messages {
            let sender_style = if msg.is_outgoing {
                Style::default()
                    .fg(Color::Green)
                    .add_modifier(Modifier::BOLD)
            } else {
                Style::default()
                    .fg(Color::Cyan)
                    .add_modifier(Modifier::BOLD)
            };

            let sender_name = if msg.is_outgoing {
                "You".to_string()
            } else {
                msg.sender_name.clone()
            };

            let read_mark = if msg.is_outgoing {
                if msg.is_read { " ✓✓" } else { " ✓" }
            } else {
                ""
            };

            // Форматируем время
            let time = format_timestamp(msg.date);

            lines.push(Line::from(vec![
                Span::styled(format!("{} ", sender_name), sender_style),
                Span::raw("── "),
                Span::styled(format!("{}{}", time, read_mark), Style::default().fg(Color::DarkGray)),
            ]));
            lines.push(Line::from(msg.content.clone()));
            lines.push(Line::from(""));
        }

        if lines.is_empty() {
            lines.push(Line::from(Span::styled(
                "Нет сообщений",
                Style::default().fg(Color::DarkGray),
            )));
        }

        // Вычисляем скролл с учётом пользовательского offset
        let visible_height = message_chunks[1].height.saturating_sub(2) as usize;
        let total_lines = lines.len();

        let base_scroll = if total_lines > visible_height {
            total_lines - visible_height
        } else {
            0
        };

        let scroll_offset = base_scroll.saturating_sub(app.message_scroll_offset) as u16;

        let messages_widget = Paragraph::new(lines)
            .block(Block::default().borders(Borders::ALL))
            .scroll((scroll_offset, 0));
        f.render_widget(messages_widget, message_chunks[1]);

        // Input box
        let input_text = if app.message_input.is_empty() {
            "> Введите сообщение...".to_string()
        } else {
            format!("> {}", app.message_input)
        };
        let input_style = if app.message_input.is_empty() {
            Style::default().fg(Color::DarkGray)
        } else {
            Style::default().fg(Color::Yellow)
        };
        let input = Paragraph::new(input_text)
            .block(Block::default().borders(Borders::ALL))
            .style(input_style);
        f.render_widget(input, message_chunks[2]);
    } else {
        let empty = Paragraph::new("Выберите чат")
            .block(Block::default().borders(Borders::ALL))
            .style(Style::default().fg(Color::DarkGray))
            .alignment(Alignment::Center);
        f.render_widget(empty, area);
    }
}