//! Tool-card visual vocabulary for the v0.6.6 transcript redesign.
//!
//! Tool cards are the boxes that appear when the agent runs `read_file`,
//! `exec_shell`, `apply_patch`, etc. The visual vocabulary is intentionally
//! sparse: a single verb glyph identifies the family, a left rail anchors
//! the card to the timeline, and the spinner cadence (720 ms/step) reuses
//! the existing tool-status animation.
//!
//! This module owns:
//!
//! - [`ToolFamily`] — the seven canonical families plus a `Generic`
//!   fallback for anything we don't have a family for yet.
//! - [`tool_family_for_title`] — maps the legacy `render_tool_header` title
//!   string (`"Shell"`, `"Patch"`, `"Workspace"`, etc.) to a family. Lets
//!   the existing call sites drop in family glyphs without re-architecting
//!   each cell.
//! - [`family_glyph`] / [`family_label`] — the verb glyph + label per
//!   family. Glyphs are single graphemes; labels are short verbs.
//! - [`CardRail`] / [`rail_glyph`] — the `╭ │ ╰` rail anchored to the
//!   left margin so the eye can group multi-line cards.
//!
//! The actual line composition still happens inside `history.rs`; this
//! module is the vocabulary, not the layout engine. Keeping it small means
//! a future visual refresh only has to touch the constants here.

/// Tool family — the verb the agent is performing. Used to pick a glyph
/// and label for the card header.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum ToolFamily {
    /// Reads, listings, exploration. `▷ read`.
    Read,
    /// Edits, patches, writes. `◆ patch`.
    Patch,
    /// Shell, child processes. `▶ run`.
    Run,
    /// Grep, fuzzy file search, web search. `⌕ find`.
    Find,
    /// Single sub-agent dispatch. `◐ delegate`.
    Delegate,
    /// Multi-agent fanout (swarm, csv). `⋮⋮ fanout`.
    Fanout,
    /// Reasoning / chain-of-thought. `… think`. Reasoning has its own
    /// render path (`render_thinking` in `history.rs`); the family is
    /// declared here for completeness so any future code that reaches for
    /// it has the matching glyph + label vocabulary.
    #[allow(dead_code)]
    Think,
    /// Anything we don't have a family glyph for yet — falls back to a
    /// neutral bullet so the card still renders cleanly.
    Generic,
}

/// Map a legacy tool-header title string (the value passed to
/// `render_tool_header`) to a family. Anything unrecognised falls back to
/// [`ToolFamily::Generic`] so cards still render — they just lose the
/// verb-glyph treatment until the family is added here.
#[must_use]
pub fn tool_family_for_title(title: &str) -> ToolFamily {
    match title {
        "Shell" => ToolFamily::Run,
        "Patch" | "Diff" => ToolFamily::Patch,
        "Workspace" | "Image" => ToolFamily::Read,
        "Search" => ToolFamily::Find,
        "Plan" | "Review" => ToolFamily::Generic,
        _ => ToolFamily::Generic,
    }
}

/// Map an arbitrary tool name (as exposed to the model — e.g. `read_file`,
/// `apply_patch`, `agent_spawn`) to a family. Used by `GenericToolCell`
/// where the `tool_family_for_title` shortcut isn't enough because every
/// generic cell shares the title `"Tool"`.
#[must_use]
pub fn tool_family_for_name(name: &str) -> ToolFamily {
    match name {
        "read_file" | "list_dir" | "view_image" => ToolFamily::Read,
        "edit_file" | "apply_patch" | "write_file" => ToolFamily::Patch,
        "exec_shell" | "exec_shell_wait" | "exec_shell_interact" => ToolFamily::Run,
        "grep_files" | "file_search" | "web_search" | "fetch_url" => ToolFamily::Find,
        "agent_spawn" => ToolFamily::Delegate,
        "agent_swarm" | "spawn_agents_on_csv" | "rlm" => ToolFamily::Fanout,
        _ => ToolFamily::Generic,
    }
}

/// The verb glyph for a family. Single grapheme so the header layout math
/// in `render_tool_header` stays simple (one cell wide).
#[must_use]
pub fn family_glyph(family: ToolFamily) -> &'static str {
    match family {
        ToolFamily::Read => "\u{25B7}",           // ▷
        ToolFamily::Patch => "\u{25C6}",          // ◆
        ToolFamily::Run => "\u{25B6}",            // ▶
        ToolFamily::Find => "\u{2315}",           // ⌕
        ToolFamily::Delegate => "\u{25D0}",       // ◐
        ToolFamily::Fanout => "\u{22EE}\u{22EE}", // ⋮⋮ (two cells)
        ToolFamily::Think => "\u{2026}",          // …
        ToolFamily::Generic => "\u{2022}",        // •
    }
}

/// The short verb label for a family — appears in card headers next to the
/// glyph. Lowercased on purpose; the verb-glyph + label is the new card
/// title vocabulary.
#[must_use]
pub fn family_label(family: ToolFamily) -> &'static str {
    match family {
        ToolFamily::Read => "read",
        ToolFamily::Patch => "patch",
        ToolFamily::Run => "run",
        ToolFamily::Find => "find",
        ToolFamily::Delegate => "delegate",
        ToolFamily::Fanout => "fanout",
        ToolFamily::Think => "think",
        ToolFamily::Generic => "tool",
    }
}

/// Position of a line within a multi-line card — drives the left-rail
/// glyph so the box reads as a contiguous group from top to bottom.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
#[allow(dead_code)] // wired by future card-refactor follow-ups
pub enum CardRail {
    /// First line of the card — the header. `╭`.
    Top,
    /// Any middle line — body content. `│`.
    Middle,
    /// Last line of the card. `╰`.
    Bottom,
    /// Single-line card — no rail at all.
    Single,
}

/// Map a [`CardRail`] position to its rail glyph. Returned as a `&str`
/// because callers paste it into a span.
#[must_use]
#[allow(dead_code)] // wired by future card-refactor follow-ups
pub fn rail_glyph(rail: CardRail) -> &'static str {
    match rail {
        CardRail::Top => "\u{256D}",    // ╭
        CardRail::Middle => "\u{2502}", // │
        CardRail::Bottom => "\u{2570}", // ╰
        CardRail::Single => "",
    }
}

#[cfg(test)]
mod tests {
    use super::{
        CardRail, ToolFamily, family_glyph, family_label, rail_glyph, tool_family_for_name,
        tool_family_for_title,
    };

    #[test]
    fn legacy_titles_route_to_expected_families() {
        assert_eq!(tool_family_for_title("Shell"), ToolFamily::Run);
        assert_eq!(tool_family_for_title("Patch"), ToolFamily::Patch);
        assert_eq!(tool_family_for_title("Workspace"), ToolFamily::Read);
        assert_eq!(tool_family_for_title("Search"), ToolFamily::Find);
        assert_eq!(tool_family_for_title("Diff"), ToolFamily::Patch);
        assert_eq!(tool_family_for_title("Plan"), ToolFamily::Generic);
        assert_eq!(tool_family_for_title("unknown title"), ToolFamily::Generic);
    }

    #[test]
    fn tool_names_route_to_families_by_verb() {
        assert_eq!(tool_family_for_name("read_file"), ToolFamily::Read);
        assert_eq!(tool_family_for_name("apply_patch"), ToolFamily::Patch);
        assert_eq!(tool_family_for_name("exec_shell"), ToolFamily::Run);
        assert_eq!(tool_family_for_name("grep_files"), ToolFamily::Find);
        assert_eq!(tool_family_for_name("agent_spawn"), ToolFamily::Delegate);
        assert_eq!(tool_family_for_name("agent_swarm"), ToolFamily::Fanout);
        assert_eq!(tool_family_for_name("rlm"), ToolFamily::Fanout);
        assert_eq!(
            tool_family_for_name("totally_new_tool"),
            ToolFamily::Generic
        );
    }

    #[test]
    fn each_family_has_a_glyph_and_label() {
        // Smoke test — surface accidental empties from a future refactor.
        for family in [
            ToolFamily::Read,
            ToolFamily::Patch,
            ToolFamily::Run,
            ToolFamily::Find,
            ToolFamily::Delegate,
            ToolFamily::Fanout,
            ToolFamily::Think,
            ToolFamily::Generic,
        ] {
            assert!(
                !family_glyph(family).is_empty(),
                "family {family:?} has empty glyph",
            );
            assert!(
                !family_label(family).is_empty(),
                "family {family:?} has empty label",
            );
        }
    }

    #[test]
    fn card_rail_glyphs_form_a_box() {
        assert_eq!(rail_glyph(CardRail::Top), "\u{256D}");
        assert_eq!(rail_glyph(CardRail::Middle), "\u{2502}");
        assert_eq!(rail_glyph(CardRail::Bottom), "\u{2570}");
        assert!(rail_glyph(CardRail::Single).is_empty());
    }
}
