// tools/edit.rs — Search-and-replace file editing

use anyhow::{Context, Result};
use serde::Deserialize;

pub fn tool() -> super::Tool {
    super::Tool {
        name: "edit_file",
        description: "Perform exact string replacement in a file. The old_string must appear exactly once (unless replace_all is true). Use read_file first to see current contents.",
        parameters_json: r#"{"type":"object","properties":{"file_path":{"type":"string","description":"Absolute path to the file to edit"},"old_string":{"type":"string","description":"The exact text to find and replace"},"new_string":{"type":"string","description":"The replacement text"},"replace_all":{"type":"boolean","description":"Replace all occurrences (default false)"}},"required":["file_path","old_string","new_string"]}"#,
        handler: |_a, v| Box::pin(async move { edit_file(&v) }),
    }
}

#[derive(Deserialize)]
struct Args { file_path: String, old_string: String, new_string: String, #[serde(default)] replace_all: bool }

fn edit_file(args: &serde_json::Value) -> Result<String> {
    let a: Args = serde_json::from_value(args.clone()).context("invalid edit_file arguments")?;
    if a.old_string == a.new_string { anyhow::bail!("old_string and new_string are identical"); }

    let content = std::fs::read_to_string(&a.file_path)
        .with_context(|| format!("Failed to read {}", a.file_path))?;
    let count = content.matches(&*a.old_string).count();
    if count == 0 { anyhow::bail!("old_string not found in {}", a.file_path); }

    if a.replace_all {
        let new_content = content.replace(&*a.old_string, &a.new_string);
        std::fs::write(&a.file_path, &new_content)
            .with_context(|| format!("Failed to write {}", a.file_path))?;
        Ok(format!("Replaced {} occurrences in {}", count, a.file_path))
    } else {
        if count > 1 {
            anyhow::bail!("old_string appears {} times in {} — use replace_all or provide more context", count, a.file_path);
        }
        let new_content = content.replacen(&*a.old_string, &a.new_string, 1);
        std::fs::write(&a.file_path, &new_content)
            .with_context(|| format!("Failed to write {}", a.file_path))?;
        Ok(format!("Edited {}", a.file_path))
    }
}