//! Chat input box and autocomplete dropdown rendering.
//! Implements the Component trait.

use super::theme::Theme;
use crate::components::Component;
use ratatui::layout::Rect;
use ratatui::style::{Modifier, Style};
use ratatui::text::{Line, Span};
use ratatui::widgets::{Block, BorderType, Borders, Paragraph};
use ratatui::Frame;

#[derive(Default)]
pub struct InputComponent;

impl Component for InputComponent {
    fn draw(&mut self, frame: &mut Frame, area: Rect, state: &crate::state::AppStateRest) {
        if state.input.autocomplete_visible && !state.input.autocomplete_candidates.is_empty() {
            let n = state.input.autocomplete_candidates.len().min(10) as u16;
            let dropdown_height = n + 2;
            let dropdown_area = Rect {
                x: area.x,
                y: area.y.saturating_sub(dropdown_height),
                width: area.width.min(45),
                height: dropdown_height,
            };
            let dropdown_title = match state.input.autocomplete_kind {
                crate::state::AutocompleteKind::Command => " ⌘ Commands ",
                crate::state::AutocompleteKind::FileMention => " 📁 Files ",
            };
            let dropdown_block = Block::default()
                .borders(Borders::ALL)
                .border_type(BorderType::Rounded)
                .border_style(Style::default().fg(Theme::BORDER))
                .title(Span::styled(
                    dropdown_title,
                    Style::default()
                        .fg(Theme::PRIMARY)
                        .add_modifier(Modifier::BOLD),
                ))
                .style(Style::default().bg(Theme::SURFACE_ELEVATED));

            let mut lines: Vec<Line> = Vec::new();
            let selected = state.input.autocomplete_idx;
            for (i, candidate) in state
                .input
                .autocomplete_candidates
                .iter()
                .enumerate()
                .take(10)
            {
                let prefix = if i == selected { "  ▸ " } else { "    " };
                let style = if i == selected {
                    Style::default()
                        .fg(Theme::TEXT)
                        .bg(Theme::HIGHLIGHT_DIM)
                        .add_modifier(Modifier::BOLD)
                } else {
                    Style::default().fg(Theme::TEXT)
                };
                let label = format!("{prefix}{candidate}");
                lines.push(Line::from(Span::styled(label, style)));
            }
            let dropdown = Paragraph::new(lines).block(dropdown_block);
            frame.render_widget(ratatui::widgets::Clear, dropdown_area);
            frame.render_widget(dropdown, dropdown_area);
        }

        let block = Block::default()
            .borders(Borders::ALL)
            .border_type(BorderType::Rounded)
            .border_style(Style::default().fg(Theme::BORDER_FOCUSED))
            .style(Style::default().bg(Theme::BG));

        let input_text = &state.input.buffer;
        let cursor_pos = state.input.cursor;

        let prompt = Span::styled(
            " ❯ ",
            Style::default()
                .fg(Theme::PRIMARY)
                .add_modifier(Modifier::BOLD),
        );

        let mut spans = vec![prompt];

        if input_text.is_empty() {
            spans.push(Span::styled(
                "Type a message, @file, or /command...",
                Style::default()
                    .fg(Theme::TEXT_DIM)
                    .add_modifier(Modifier::ITALIC),
            ));
        } else {
            let (before, after) = input_text.split_at(cursor_pos);
            spans.push(Span::raw(before.to_string()));
            let (cursor_char, after_char) = if after.is_empty() {
                (" ".to_string(), "")
            } else {
                let c = after.chars().next().unwrap();
                let char_len = c.len_utf8();
                (c.to_string(), &after[char_len..])
            };

            // Blinking cursor logic based on tick count
            let cursor_style = if state.misc.tick_count % 10 < 5 {
                Style::default()
                    .bg(Theme::PRIMARY)
                    .fg(Theme::BG)
                    .add_modifier(Modifier::BOLD)
            } else {
                Style::default()
                    .bg(Theme::TEXT_DIM)
                    .fg(Theme::BG)
                    .add_modifier(Modifier::BOLD)
            };

            spans.push(Span::styled(cursor_char, cursor_style));
            if !after_char.is_empty() {
                spans.push(Span::raw(after_char.to_string()));
            }
        }

        let line = Line::from(spans);
        let paragraph = Paragraph::new(line).block(block);
        frame.render_widget(paragraph, area);
    }
}