//! Account switcher modal
//!
//! Renders a centered popup with account list (SelectAccount) or
//! new account name input (AddAccount).

use crate::app::{AccountSwitcherState, App};
use crate::tdlib::TdClientTrait;
use ratatui::{
    layout::Rect,
    style::{Color, Modifier, Style},
    text::{Line, Span},
    widgets::{Block, Borders, Clear, Paragraph},
    Frame,
};

/// Renders the account switcher modal overlay.
pub fn render<T: TdClientTrait>(f: &mut Frame, area: Rect, app: &App<T>) {
    let Some(state) = &app.account_switcher else {
        return;
    };

    match state {
        AccountSwitcherState::SelectAccount { accounts, selected_index, current_account } => {
            render_select_account(f, area, accounts, *selected_index, current_account);
        }
        AccountSwitcherState::AddAccount { name_input, cursor_position, error } => {
            render_add_account(f, area, name_input, *cursor_position, error.as_deref());
        }
    }
}

fn render_select_account(
    f: &mut Frame,
    area: Rect,
    accounts: &[crate::accounts::AccountProfile],
    selected_index: usize,
    current_account: &str,
) {
    let mut lines: Vec<Line> = Vec::new();
    lines.push(Line::from(""));

    for (idx, account) in accounts.iter().enumerate() {
        let is_selected = idx == selected_index;
        let is_current = account.name == current_account;

        let marker = if is_current { "● " } else { "  " };
        let suffix = if is_current { " (текущий)" } else { "" };
        let display = format!("{}{} ({}){}", marker, account.name, account.display_name, suffix);

        let style = if is_selected {
            Style::default()
                .fg(Color::Yellow)
                .add_modifier(Modifier::BOLD)
        } else if is_current {
            Style::default().fg(Color::Green)
        } else {
            Style::default().fg(Color::White)
        };

        lines.push(Line::from(Span::styled(format!("  {}", display), style)));
    }

    // Separator
    lines.push(Line::from(Span::styled(
        "  ──────────────────────",
        Style::default().fg(Color::DarkGray),
    )));

    // Add account item
    let add_selected = selected_index == accounts.len();
    let add_style = if add_selected {
        Style::default()
            .fg(Color::Yellow)
            .add_modifier(Modifier::BOLD)
    } else {
        Style::default().fg(Color::Cyan)
    };
    lines.push(Line::from(Span::styled("  + Добавить аккаунт", add_style)));

    lines.push(Line::from(""));

    // Help bar
    lines.push(Line::from(vec![
        Span::styled(" j/k ", Style::default().fg(Color::Yellow)),
        Span::styled("Nav", Style::default().fg(Color::DarkGray)),
        Span::raw("  "),
        Span::styled(" Enter ", Style::default().fg(Color::Green)),
        Span::styled("Select", Style::default().fg(Color::DarkGray)),
        Span::raw("  "),
        Span::styled(" a ", Style::default().fg(Color::Cyan)),
        Span::styled("Add", Style::default().fg(Color::DarkGray)),
        Span::raw("  "),
        Span::styled(" Esc ", Style::default().fg(Color::Red)),
        Span::styled("Close", Style::default().fg(Color::DarkGray)),
    ]));

    // Calculate dynamic height: header(3) + accounts + separator(1) + add(1) + empty(1) + help(1) + footer(1)
    let content_height = (accounts.len() as u16) + 7;
    let height = content_height.min(area.height.saturating_sub(4));
    let width = 40u16.min(area.width.saturating_sub(4));

    let x = area.x + (area.width.saturating_sub(width)) / 2;
    let y = area.y + (area.height.saturating_sub(height)) / 2;
    let modal_area = Rect::new(x, y, width, height);

    f.render_widget(Clear, modal_area);

    let modal = Paragraph::new(lines).block(
        Block::default()
            .borders(Borders::ALL)
            .border_style(Style::default().fg(Color::Cyan))
            .title(" АККАУНТЫ ")
            .title_style(
                Style::default()
                    .fg(Color::Cyan)
                    .add_modifier(Modifier::BOLD),
            ),
    );

    f.render_widget(modal, modal_area);
}

fn render_add_account(
    f: &mut Frame,
    area: Rect,
    name_input: &str,
    _cursor_position: usize,
    error: Option<&str>,
) {
    let mut lines: Vec<Line> = Vec::new();
    lines.push(Line::from(""));

    // Input field
    let input_display = if name_input.is_empty() {
        Span::styled("_", Style::default().fg(Color::DarkGray))
    } else {
        Span::styled(format!("{}_", name_input), Style::default().fg(Color::White))
    };
    lines.push(Line::from(vec![
        Span::styled("  Имя: ", Style::default().fg(Color::Cyan)),
        input_display,
    ]));

    // Hint
    lines.push(Line::from(Span::styled(
        "  (a-z, 0-9, -, _)",
        Style::default().fg(Color::DarkGray),
    )));

    lines.push(Line::from(""));

    // Error
    if let Some(err) = error {
        lines.push(Line::from(Span::styled(format!("  {}", err), Style::default().fg(Color::Red))));
        lines.push(Line::from(""));
    }

    // Help bar
    lines.push(Line::from(vec![
        Span::styled(" Enter ", Style::default().fg(Color::Green)),
        Span::styled("Create", Style::default().fg(Color::DarkGray)),
        Span::raw("  "),
        Span::styled(" Esc ", Style::default().fg(Color::Red)),
        Span::styled("Back", Style::default().fg(Color::DarkGray)),
    ]));

    let height = if error.is_some() { 10 } else { 8 };
    let height = (height as u16).min(area.height.saturating_sub(4));
    let width = 40u16.min(area.width.saturating_sub(4));

    let x = area.x + (area.width.saturating_sub(width)) / 2;
    let y = area.y + (area.height.saturating_sub(height)) / 2;
    let modal_area = Rect::new(x, y, width, height);

    f.render_widget(Clear, modal_area);

    let modal = Paragraph::new(lines).block(
        Block::default()
            .borders(Borders::ALL)
            .border_style(Style::default().fg(Color::Cyan))
            .title(" НОВЫЙ АККАУНТ ")
            .title_style(
                Style::default()
                    .fg(Color::Cyan)
                    .add_modifier(Modifier::BOLD),
            ),
    );

    f.render_widget(modal, modal_area);
}