sgr-agent 0.7.7

use serde_json::Value;
use std::fmt;

/// UTF-8 safe string operations missing from stdlib.
pub trait StrExt {
    /// Truncate to max bytes at char boundary.
    fn trunc(&self, max_bytes: usize) -> &str;

    /// Truncate with ellipsis for display: `"long text…"`.
    fn ellipsis(&self, max_bytes: usize) -> Ellipsis<'_>;

    /// Single-line preview: collapse whitespace + truncate.
    fn oneline(&self, max_bytes: usize) -> String;
}

impl StrExt for str {
    #[inline]
    fn trunc(&self, max_bytes: usize) -> &str {
        &self[..self.floor_char_boundary(max_bytes)]
    }

    #[inline]
    fn ellipsis(&self, max_bytes: usize) -> Ellipsis<'_> {
        Ellipsis(self, max_bytes)
    }

    fn oneline(&self, max_bytes: usize) -> String {
        let flat: String = self.split_whitespace().collect::<Vec<_>>().join(" ");
        flat.trunc(max_bytes).to_string()
    }
}

/// Display wrapper that appends "…" when truncated.
pub struct Ellipsis<'a>(&'a str, usize);

impl fmt::Display for Ellipsis<'_> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let s = self.0.trunc(self.1);
        f.write_str(s)?;
        if s.len() < self.0.len() {
            f.write_str("…")?;
        }
        Ok(())
    }
}

/// Parse tool call arguments JSON with llm_json repair fallback.
/// Handles common LLM mistakes: escaped quotes, trailing commas, missing braces.
pub fn parse_tool_args(args_str: &str) -> Value {
    serde_json::from_str(args_str).unwrap_or_else(|_| {
        match llm_json::repair_json(args_str, &llm_json::RepairOptions::default()) {
            Ok(fixed) => serde_json::from_str(&fixed).unwrap_or(Value::Object(Default::default())),
            Err(_) => Value::Object(Default::default()),
        }
    })
}