vtcode_tui/core_tui/session/

header.rs

use std::fmt::Write;

use ratatui::{
    Frame,
    layout::Rect,
    style::{Color, Modifier, Style},
    text::{Line, Span},
    widgets::{Block, Paragraph, Wrap},
};
use unicode_segmentation::UnicodeSegmentation;

use crate::config::constants::ui;

use super::super::types::{
    InlineHeaderContext, InlineHeaderHighlight, InlineHeaderStatusBadge, InlineHeaderStatusTone,
};
use super::terminal_capabilities;
use super::{Session, ratatui_color_from_ansi};

fn clean_reasoning_text(text: &str) -> String {
    text.lines()
        .map(str::trim_end)
        .filter(|line| !line.trim().is_empty())
        .collect::<Vec<_>>()
        .join("\n")
}

fn capitalize_first_letter(s: &str) -> String {
    let mut chars = s.chars();
    match chars.next() {
        None => String::new(),
        Some(first) => first.to_uppercase().collect::<String>() + chars.as_str(),
    }
}

fn compact_tools_format(tools_str: &str) -> String {
    // Input format: "allow X · prompt Y · deny Z"
    // Output format: "N" where N is the number of allowed (currently running) tools

    let parts = tools_str.split(" · ");
    let mut allow_count = 0;

    for part in parts {
        let trimmed = part.trim();
        if let Some(num_str) = trimmed.strip_prefix("allow ")
            && let Ok(num) = num_str.parse::<i32>()
        {
            allow_count = num;
            break; // We found the allow count, no need to continue
        }
    }

    allow_count.to_string()
}

fn compact_context_window_label(context_window_size: usize) -> String {
    if context_window_size >= 1_000_000 {
        format!("{}M", context_window_size / 1_000_000)
    } else if context_window_size >= 1_000 {
        format!("{}K", context_window_size / 1_000)
    } else {
        context_window_size.to_string()
    }
}

fn line_is_empty(spans: &[Span<'static>]) -> bool {
    spans.len() == 1 && spans.first().is_some_and(|span| span.content.is_empty())
}

fn header_status_badge_style(badge: &InlineHeaderStatusBadge, fallback: Style) -> Style {
    let color = match badge.tone {
        InlineHeaderStatusTone::Ready => Color::Green,
        InlineHeaderStatusTone::Warning => Color::Yellow,
        InlineHeaderStatusTone::Error => Color::Red,
    };
    fallback.fg(color).add_modifier(Modifier::BOLD)
}

impl Session {
    pub(super) fn render_header(&self, frame: &mut Frame<'_>, area: Rect, lines: &[Line<'static>]) {
        if area.height == 0 || area.width == 0 {
            return;
        }

        let paragraph = self.build_header_paragraph(lines);

        frame.render_widget(paragraph, area);
    }

    pub(crate) fn header_lines(&mut self) -> Vec<Line<'static>> {
        if let Some(cached) = &self.header_lines_cache {
            return cached.clone();
        }

        let lines = vec![self.header_compact_line()];
        self.header_lines_cache = Some(lines.clone());
        lines
    }

    pub(crate) fn header_height_from_lines(&mut self, width: u16, lines: &[Line<'static>]) -> u16 {
        if width == 0 {
            return self.header_rows.max(ui::INLINE_HEADER_HEIGHT);
        }

        if let Some(&height) = self.header_height_cache.get(&width) {
            return height;
        }

        let paragraph = self.build_header_paragraph(lines);
        let measured = paragraph.line_count(width);
        let resolved = u16::try_from(measured).unwrap_or(u16::MAX);
        // Limit to max 3 lines to accommodate suggestions
        let resolved = resolved.clamp(ui::INLINE_HEADER_HEIGHT, 3);
        self.header_height_cache.insert(width, resolved);
        resolved
    }

    pub(crate) fn build_header_paragraph(&self, lines: &[Line<'static>]) -> Paragraph<'static> {
        let block = Block::bordered()
            .title(self.header_block_title())
            .border_type(terminal_capabilities::get_border_type())
            .style(self.styles.default_style());

        Paragraph::new(lines.to_vec())
            .style(self.styles.default_style())
            .wrap(Wrap { trim: true })
            .block(block)
    }

    #[cfg(test)]
    pub(super) fn header_height_for_width(&mut self, width: u16) -> u16 {
        let lines = self.header_lines();
        self.header_height_from_lines(width, &lines)
    }

    pub fn header_block_title(&self) -> Line<'static> {
        let fallback = InlineHeaderContext::default();
        let version = if self.header_context.version.trim().is_empty() {
            fallback.version
        } else {
            self.header_context.version.clone()
        };

        let app_name = if self.header_context.app_name.trim().is_empty() {
            ui::HEADER_VERSION_PREFIX
        } else {
            self.header_context.app_name.trim()
        };
        let prompt = format!("{}{} ", ui::HEADER_VERSION_PROMPT, app_name);
        let version_text = format!(
            "{}{}{}",
            ui::HEADER_VERSION_LEFT_DELIMITER,
            version.trim(),
            ui::HEADER_VERSION_RIGHT_DELIMITER
        );

        let prompt_style = self.section_title_style();
        let version_style = self.header_secondary_style().add_modifier(Modifier::DIM);

        Line::from(vec![
            Span::styled(prompt, prompt_style),
            Span::styled(version_text, version_style),
        ])
    }

    pub fn header_title_line(&self) -> Line<'static> {
        // First line: badge-style provider + model + reasoning summary
        let mut spans = Vec::new();

        let provider = self.header_provider_short_value();
        let model = self.header_model_short_value();
        let reasoning = self.header_reasoning_short_value();

        if !provider.is_empty() {
            let capitalized_provider = capitalize_first_letter(&provider);
            let mut style = self.header_primary_style();
            style = style.add_modifier(Modifier::BOLD);
            spans.push(Span::styled(capitalized_provider, style));
        }

        if !model.is_empty() {
            if !spans.is_empty() {
                spans.push(Span::raw(" "));
            }
            let mut style = self.header_primary_style();
            style = style.add_modifier(Modifier::ITALIC);
            spans.push(Span::styled(model, style));
        }

        if !reasoning.is_empty() {
            if !spans.is_empty() {
                spans.push(Span::raw(" "));
            }
            let mut style = self.header_secondary_style();
            style = style.add_modifier(Modifier::ITALIC | Modifier::DIM);

            if let Some(stage) = &self.header_context.reasoning_stage {
                let mut stage_style = style;
                stage_style = stage_style
                    .remove_modifier(Modifier::DIM)
                    .add_modifier(Modifier::BOLD);
                spans.push(Span::styled(format!("[{}]", stage), stage_style));
                spans.push(Span::raw(" "));
            }

            spans.push(Span::styled(reasoning.to_string(), style));
        }

        if spans.is_empty() {
            spans.push(Span::raw(String::new()));
        }

        Line::from(spans)
    }

    fn header_compact_line(&self) -> Line<'static> {
        let mut spans = self.header_title_line().spans;
        if line_is_empty(&spans) {
            spans.clear();
        }

        let mut meta_spans = self.header_meta_line().spans;
        if line_is_empty(&meta_spans) {
            meta_spans.clear();
        }

        let mut tail_spans = if self.should_show_suggestions() {
            self.header_suggestions_line()
        } else {
            self.header_highlights_line()
        }
        .map(|line| line.spans)
        .unwrap_or_default();

        if line_is_empty(&tail_spans) {
            tail_spans.clear();
        }

        let separator_style = self.header_secondary_style();
        let separator = Span::styled(
            ui::HEADER_MODE_PRIMARY_SEPARATOR.to_owned(),
            separator_style,
        );

        let mut append_section = |section: &mut Vec<Span<'static>>| {
            if section.is_empty() {
                return;
            }
            if !spans.is_empty() {
                spans.push(separator.clone());
            }
            spans.append(section);
        };

        append_section(&mut meta_spans);
        append_section(&mut tail_spans);

        if spans.is_empty() {
            spans.push(Span::raw(String::new()));
        }

        Line::from(spans)
    }

    fn header_provider_value(&self) -> String {
        let trimmed = self.header_context.provider.trim();
        if trimmed.is_empty() {
            InlineHeaderContext::default().provider
        } else {
            self.header_context.provider.clone()
        }
    }

    fn header_model_value(&self) -> String {
        let trimmed = self.header_context.model.trim();
        if trimmed.is_empty() {
            InlineHeaderContext::default().model
        } else {
            self.header_context.model.clone()
        }
    }

    fn header_mode_label(&self) -> String {
        let trimmed = self.header_context.mode.trim();
        if trimmed.is_empty() {
            InlineHeaderContext::default().mode
        } else {
            self.header_context.mode.clone()
        }
    }

    pub fn header_mode_short_label(&self) -> String {
        let full = self.header_mode_label();
        let value = full.trim();
        if value.eq_ignore_ascii_case(ui::HEADER_MODE_AUTO) {
            return "Auto".to_owned();
        }
        if value.eq_ignore_ascii_case(ui::HEADER_MODE_INLINE) {
            return "Inline".to_owned();
        }
        if value.eq_ignore_ascii_case(ui::HEADER_MODE_ALTERNATE) {
            return "Alternate".to_owned();
        }

        // Handle common abbreviations with more descriptive names
        if value.to_lowercase() == "std" {
            return "Session: Standard".to_owned();
        }

        let compact = value
            .strip_suffix(ui::HEADER_MODE_FULL_AUTO_SUFFIX)
            .unwrap_or(value)
            .trim();
        compact.to_owned()
    }

    fn header_reasoning_value(&self) -> Option<String> {
        let raw_reasoning = &self.header_context.reasoning;
        let cleaned = clean_reasoning_text(raw_reasoning);
        let trimmed = cleaned.trim();
        let value = if trimmed.is_empty() {
            InlineHeaderContext::default().reasoning
        } else {
            cleaned
        };
        if value.trim().is_empty() {
            None
        } else {
            Some(value)
        }
    }

    pub fn header_provider_short_value(&self) -> String {
        let value = self.header_provider_value();
        Self::strip_prefix(&value, ui::HEADER_PROVIDER_PREFIX)
            .trim()
            .to_owned()
    }

    pub fn header_model_short_value(&self) -> String {
        let value = self.header_model_value();
        let model = Self::strip_prefix(&value, ui::HEADER_MODEL_PREFIX)
            .trim()
            .to_owned();

        match self.header_context.context_window_size {
            Some(context_window_size) if context_window_size > 0 => {
                format!(
                    "{} ({})",
                    model,
                    compact_context_window_label(context_window_size)
                )
            }
            _ => model,
        }
    }

    pub fn header_reasoning_short_value(&self) -> String {
        let value = self.header_reasoning_value().unwrap_or_default();
        Self::strip_prefix(&value, ui::HEADER_REASONING_PREFIX)
            .trim()
            .to_owned()
    }

    pub fn header_chain_values(&self) -> Vec<String> {
        let defaults = InlineHeaderContext::default();
        let mut values = Vec::new();

        for (value, fallback) in [
            (&self.header_context.tools, defaults.tools),
            (&self.header_context.git, defaults.git),
        ] {
            let selected = if value.trim().is_empty() {
                fallback
            } else {
                value.clone()
            };
            let trimmed = selected.trim();
            if trimmed.is_empty() {
                continue;
            }

            if let Some(body) = trimmed.strip_prefix(ui::HEADER_TOOLS_PREFIX) {
                let compact_tools = compact_tools_format(body.trim());
                values.push(format!("Tools: {}", compact_tools));
                continue;
            }

            if let Some(body) = trimmed.strip_prefix(ui::HEADER_GIT_PREFIX) {
                let body = body.trim();
                if !body.is_empty() {
                    values.push(body.to_owned());
                }
                continue;
            }

            values.push(selected);
        }

        values
    }

    pub fn header_meta_line(&self) -> Line<'static> {
        use super::super::types::EditingMode;

        let mut spans = Vec::new();

        let mut first_section = true;
        let separator_style = self.header_secondary_style();

        let push_badge =
            |spans: &mut Vec<Span<'static>>, text: String, style: Style, first: &mut bool| {
                if !*first {
                    spans.push(Span::styled(
                        ui::HEADER_MODE_SECONDARY_SEPARATOR.to_owned(),
                        separator_style,
                    ));
                }
                spans.push(Span::styled(text, style));
                *first = false;
            };

        // Show editing mode badge with color coding
        if self.header_context.editing_mode == EditingMode::Plan {
            let badge_style = Style::default()
                .fg(Color::Yellow)
                .add_modifier(Modifier::BOLD);
            push_badge(
                &mut spans,
                "Plan mode on".to_string(),
                badge_style,
                &mut first_section,
            );
        }

        // Show autonomous mode indicator
        if self.header_context.autonomous_mode {
            let badge_style = Style::default()
                .fg(Color::Green)
                .add_modifier(Modifier::BOLD);
            push_badge(
                &mut spans,
                "[AUTO]".to_string(),
                badge_style,
                &mut first_section,
            );
        }

        // Show trust level badge with color coding
        let trust_value = self.header_context.workspace_trust.to_lowercase();
        if trust_value.contains("full auto") || trust_value.contains("full_auto") {
            let badge_style = Style::default()
                .fg(Color::Cyan)
                .add_modifier(Modifier::BOLD);
            push_badge(
                &mut spans,
                "Accept edits".to_string(),
                badge_style,
                &mut first_section,
            );
        } else if trust_value.contains("tools policy") || trust_value.contains("tools_policy") {
            let badge_style = Style::default()
                .fg(Color::Green)
                .add_modifier(Modifier::BOLD);
            push_badge(
                &mut spans,
                "[SAFE]".to_string(),
                badge_style,
                &mut first_section,
            );
        }

        if let Some(badge) = self
            .header_context
            .search_tools
            .as_ref()
            .filter(|badge| !badge.text.trim().is_empty())
        {
            if !first_section {
                spans.push(Span::styled(
                    ui::HEADER_MODE_SECONDARY_SEPARATOR.to_owned(),
                    self.header_secondary_style(),
                ));
            }
            let style = header_status_badge_style(badge, self.header_primary_style());
            spans.push(Span::styled(badge.text.clone(), style));
            first_section = false;
        }

        for value in self.header_chain_values() {
            if !first_section {
                spans.push(Span::styled(
                    ui::HEADER_MODE_SECONDARY_SEPARATOR.to_owned(),
                    self.header_secondary_style(),
                ));
            }
            spans.push(Span::styled(value, self.header_primary_style()));
            first_section = false;
        }

        if spans.is_empty() {
            spans.push(Span::raw(String::new()));
        }

        Line::from(spans)
    }

    fn header_highlights_line(&self) -> Option<Line<'static>> {
        let mut spans = Vec::new();
        let mut first_section = true;

        for highlight in &self.header_context.highlights {
            let title = highlight.title.trim();
            let summary = self.header_highlight_summary(highlight);

            if title.is_empty() && summary.is_none() {
                continue;
            }

            if !first_section {
                spans.push(Span::styled(
                    ui::HEADER_META_SEPARATOR.to_owned(),
                    self.header_secondary_style(),
                ));
            }

            if !title.is_empty() {
                let mut title_style = self.header_secondary_style();
                title_style = title_style.add_modifier(Modifier::BOLD);
                let mut title_text = title.to_owned();
                if summary.is_some() {
                    title_text.push(':');
                }
                spans.push(Span::styled(title_text, title_style));
                if summary.is_some() {
                    spans.push(Span::styled(" ".to_owned(), self.header_secondary_style()));
                }
            }

            if let Some(body) = summary {
                spans.push(Span::styled(body, self.header_primary_style()));
            }

            first_section = false;
        }

        if spans.is_empty() {
            None
        } else {
            Some(Line::from(spans))
        }
    }

    fn header_highlight_summary(&self, highlight: &InlineHeaderHighlight) -> Option<String> {
        let entries: Vec<String> = highlight
            .lines
            .iter()
            .map(|line| line.trim())
            .filter(|line| !line.is_empty())
            .map(|line| {
                let stripped = line
                    .strip_prefix("- ")
                    .or_else(|| line.strip_prefix("• "))
                    .unwrap_or(line);
                stripped.trim().to_owned()
            })
            .collect();

        if entries.is_empty() {
            return None;
        }

        Some(self.compact_highlight_entries(&entries))
    }

    fn compact_highlight_entries(&self, entries: &[String]) -> String {
        let mut summary =
            self.truncate_highlight_preview(entries.first().map(String::as_str).unwrap_or(""));
        if entries.len() > 1 {
            let remaining = entries.len() - 1;
            if !summary.is_empty() {
                let _ = write!(summary, " (+{} more)", remaining);
            } else {
                summary = format!("(+{} more)", remaining);
            }
        }
        summary
    }

    fn truncate_highlight_preview(&self, text: &str) -> String {
        let max = ui::HEADER_HIGHLIGHT_PREVIEW_MAX_CHARS;
        if max == 0 {
            return String::new();
        }

        let grapheme_count = text.graphemes(true).count();
        if grapheme_count <= max {
            return text.to_owned();
        }

        // Optimization: return early if string is short (already checked above with grapheme count)
        // This is safe because count() <= max means it doesn't need truncation.

        let mut truncated = String::new();
        // pre-allocate capacity
        truncated.reserve(text.len().min(max * 4));
        for grapheme in text.graphemes(true).take(max.saturating_sub(1)) {
            truncated.push_str(grapheme);
        }
        truncated.push_str(ui::INLINE_PREVIEW_ELLIPSIS);
        truncated
    }

    /// Determine if suggestions should be shown in the header
    fn should_show_suggestions(&self) -> bool {
        // Show suggestions when input is empty or starts with /
        self.input_manager.content().is_empty() || self.input_manager.content().starts_with('/')
    }

    /// Generate header line with slash command and keyboard shortcut suggestions
    fn header_suggestions_line(&self) -> Option<Line<'static>> {
        let spans = vec![
            Span::styled(
                "/help",
                self.header_primary_style().add_modifier(Modifier::BOLD),
            ),
            Span::styled(
                " · ",
                self.header_secondary_style().add_modifier(Modifier::DIM),
            ),
            Span::styled(
                "/model",
                self.header_primary_style().add_modifier(Modifier::BOLD),
            ),
            Span::styled(
                "  |  ",
                self.header_secondary_style().add_modifier(Modifier::DIM),
            ),
            Span::styled(
                "↑↓",
                self.header_primary_style().add_modifier(Modifier::BOLD),
            ),
            Span::styled(" Nav · ", self.header_secondary_style()),
            Span::styled(
                "Tab",
                self.header_primary_style().add_modifier(Modifier::BOLD),
            ),
            Span::styled(" Complete", self.header_secondary_style()),
        ];

        Some(Line::from(spans))
    }

    pub(super) fn section_title_style(&self) -> Style {
        let mut style = self.styles.default_style().add_modifier(Modifier::BOLD);
        if let Some(primary) = self.theme.primary.or(self.theme.foreground) {
            style = style.fg(ratatui_color_from_ansi(primary));
        }
        style
    }

    fn header_primary_style(&self) -> Style {
        let mut style = self.styles.default_style();
        if let Some(primary) = self.theme.primary.or(self.theme.foreground) {
            style = style.fg(ratatui_color_from_ansi(primary));
        }
        style
    }

    pub(super) fn header_secondary_style(&self) -> Style {
        let mut style = self.styles.default_style();
        if let Some(secondary) = self.theme.secondary.or(self.theme.foreground) {
            style = style.fg(ratatui_color_from_ansi(secondary));
        }
        style
    }

    fn strip_prefix<'a>(value: &'a str, prefix: &str) -> &'a str {
        value.strip_prefix(prefix).unwrap_or(value)
    }
}