//! Tool descriptions and file operations for the agent.

use crate::llm::Tool;
use sausage_actor::{Value, json};
use std::io;

pub fn definitions() -> Vec<Tool> {
    vec![
        Tool {
            name: "send_message",
            description: "Send an actor a JSON body with a `type`. `broker` and `cargo` are built-in actors; see `/actor/broker/public/PROTOCOL.md`. With `wait_seconds`, the reply's `reply_to` matches the returned ID. Returns the ID, reply, and other messages received.",
            parameters: schema(
                json!({
                    "to": {"type": "string", "description": "Actor ID"},
                    "body": {"type": "object", "description": "JSON object with a type field"},
                    "wait_seconds": {"type": "number", "description": "Seconds to wait for a reply. Default 0."}
                }),
                &["to", "body"],
            ),
        },
        Tool {
            name: "read_file",
            description: "Read a text file under `/data`, `/public`, or `/actor/<id>`. Reads all bytes by default; `offset` and `max_bytes` are optional.",
            parameters: schema(
                json!({
                    "path": {"type": "string"},
                    "offset": {"type": "integer", "description": "Byte offset (default 0)"},
                    "max_bytes": {"type": "integer", "description": "Optional maximum number of bytes to read"}
                }),
                &["path"],
            ),
        },
        Tool {
            name: "write_file",
            description: "Write text under `/data` or `/public`. Parent folders are created.",
            parameters: schema(
                json!({"path": {"type": "string"}, "content": {"type": "string"}}),
                &["path", "content"],
            ),
        },
        Tool {
            name: "list_dir",
            description: "List entries in a directory under `/data`, `/public`, or `/actor/<id>`. Returns each name, type, and size.",
            parameters: schema(json!({"path": {"type": "string"}}), &["path"]),
        },
        Tool {
            name: "copy_dir",
            description: "Copy a directory tree, for example `/actor/<id>/source` to `/public/drafts/<id>`. Skips `target/` folders.",
            parameters: schema(
                json!({"from": {"type": "string"}, "to": {"type": "string"}}),
                &["from", "to"],
            ),
        },
    ]
}

fn schema(properties: Value, required: &[&str]) -> Value {
    json!({"type": "object", "properties": properties, "required": required})
}

pub fn run(name: &str, args: &Value) -> io::Result<Value> {
    match name {
        "read_file" => read_file(args),
        "write_file" => write_file(args),
        "list_dir" => list_dir(args),
        "copy_dir" => copy_dir(args),
        other => Ok(json!({"error": format!("unknown tool {other}")})),
    }
}

fn read_file(args: &Value) -> io::Result<Value> {
    let path = args["path"].as_str().unwrap_or_default();
    let bytes = std::fs::read(path)?;
    let offset = (args["offset"].as_u64().unwrap_or(0) as usize).min(bytes.len());
    let end = args["max_bytes"].as_u64().map_or(bytes.len(), |max| {
        offset.saturating_add(max as usize).min(bytes.len())
    });
    Ok(json!({
        "path": path,
        "size": bytes.len(),
        "offset": offset,
        "content": String::from_utf8_lossy(&bytes[offset..end]),
        "truncated": end < bytes.len(),
    }))
}

fn write_file(args: &Value) -> io::Result<Value> {
    let path = args["path"].as_str().unwrap_or_default();
    if let Some(parent) = std::path::Path::new(path).parent() {
        let _ = std::fs::create_dir_all(parent);
    }
    std::fs::write(path, args["content"].as_str().unwrap_or_default())?;
    Ok(json!({"written": path}))
}

fn list_dir(args: &Value) -> io::Result<Value> {
    let mut entries: Vec<Value> = std::fs::read_dir(args["path"].as_str().unwrap_or_default())?
        .filter_map(|entry| entry.ok())
        .map(|entry| {
            let metadata = entry.metadata().ok();
            json!({
                "name": entry.file_name().to_string_lossy(),
                "type": if metadata.as_ref().is_some_and(|meta| meta.is_dir()) { "dir" } else { "file" },
                "size": metadata.map(|meta| meta.len()),
            })
        })
        .collect();
    entries.sort_by(|left, right| left["name"].as_str().cmp(&right["name"].as_str()));
    Ok(json!({"entries": entries}))
}

fn copy_dir(args: &Value) -> io::Result<Value> {
    let count = copy_tree(
        args["from"].as_str().unwrap_or_default(),
        args["to"].as_str().unwrap_or_default(),
    )?;
    Ok(json!({"copied_files": count}))
}

fn copy_tree(from: &str, to: &str) -> io::Result<u64> {
    std::fs::create_dir_all(to)?;
    let mut count = 0;
    for entry in std::fs::read_dir(from)? {
        let entry = entry?;
        let name = entry.file_name().to_string_lossy().to_string();
        let src = format!("{from}/{name}");
        let dst = format!("{to}/{name}");
        if entry.file_type()?.is_dir() {
            if name != "target" {
                count += copy_tree(&src, &dst)?;
            }
        } else {
            std::fs::copy(src, dst)?;
            count += 1;
        }
    }
    Ok(count)
}