//! Tool: `delete` — remove a file or empty directory relative to a workspace root.

use std::fs;
use std::path::PathBuf;
use serde_json::{json, Value};
use anyhow::{Result, anyhow};
use super::super::Tool;
use super::super::ToolCtx;
use super::super::resolve_path;
use super::helpers::arg_str;

/// Tool: delete a file or empty directory. Refuses non-empty directories.
pub struct Delete;

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

    fn description(&self) -> &'static str {
        "Delete a file or empty directory. Will not delete non-empty directories."
    }

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

    /// Delete a file or empty directory. Returns success message or errors on failure.
    ///
    /// Flow: resolve path → check existence → check dir/file → remove.
    /// Only empty directories are deletable (non-empty returns an error).
    fn run(&self, ctx: &ToolCtx, args: &Value) -> Result<String> {
        let rel = arg_str(args, "path")?;
        let path: PathBuf = resolve_path(&ctx.workspaces, &rel)?;

        if !path.exists() {
            return Ok(format!("path '{}' does not exist (resolved to {})", rel, path.display()));
        }

        let metadata = path.metadata()
            .map_err(|e| anyhow!("failed to read metadata for '{rel}': {e}"))?;

        if metadata.is_dir() {
            let is_empty = fs::read_dir(&path)
                .map_err(|e| anyhow!("failed to read directory '{rel}': {e}"))?
                .next()
                .is_none();
            if is_empty {
                fs::remove_dir(&path)
                    .map_err(|e| anyhow!("failed to remove directory '{rel}': {e}"))?;
                Ok(format!("removed empty directory {rel}"))
            } else {
                anyhow::bail!("directory '{rel}' is not empty (refusing to delete)");
            }
        } else {
            fs::remove_file(&path)
                .map_err(|e| anyhow!("failed to delete '{rel}': {e}"))?;
            Ok(format!("deleted {rel}"))
        }
    }
}