//! `cd` tool: verify and resolve a workspace-relative directory path.
use super::super::Tool;
use super::super::ToolCtx;
use anyhow::Result;
use serde_json::{json, Value};

/// Tool that resolves a workspace-relative path and reports whether it exists and is a dir.
pub struct Cd;

impl Tool for Cd {
    fn name(&self) -> &'static str {
        "cd"
    }

    fn description(&self) -> &'static str {
        "Check if a directory exists within the workspace and print its resolved path. Use this to verify a directory path before running other commands there."
    }

    fn parameters(&self) -> Value {
        json!({
            "type": "object",
            "properties": {
                "path": {
                    "type": "string",
                    "description": "Directory path (relative to workspace root)"
                }
            },
            "required": ["path"]
        })
    }

    /// Resolve `path` against the workspace roots and report its status.
    ///
    /// Flow: extract `path` → `resolve_path` (sandboxed to `ctx.workspaces`) →
    ///       check `exists()` and `is_dir()` → canonicalize → return canonical path.
    ///
    /// Why: the agent has no persistent cwd between tool calls; "cd" here is purely a
    /// verification + canonicalization helper rather than a state change.
    ///
    /// Return: canonical path on success; explicit "does not exist" / "not a directory"
    /// message (still `Ok`) so the model can react without treating it as an error.
    fn run(&self, ctx: &ToolCtx, args: &Value) -> Result<String> {
        let rel = crate::tool::arg_str(args, "path")?;

        let path = super::super::resolve_path(&ctx.workspaces, &rel)?;

        if !path.exists() {
            return Ok(super::path_not_found(&rel, &path));
        }
        if !path.is_dir() {
            return Ok(super::path_not_a_directory(&rel, &path));
        }

        let canon = path.canonicalize().unwrap_or(path);
        Ok(format!("{}", canon.display()))
    }
}