package file

import (
	"context"
	"fmt"
	"os"
	"path/filepath"

	"github.com/enmanuel/agents/internal/config"
	"github.com/enmanuel/agents/tools"
)

// NewDeleteFile creates a delete_file tool that deletes a single file.
// Deny-by-default: if AllowedPaths is empty, all operations are rejected.
// Rejects if ReadOnly is true. Only deletes files, never directories.
// Resolves symlinks before deleting to prevent escaping allowed paths.
func NewDeleteFile(cfg config.FileOpsCfg) tools.Tool {
	return tools.Tool{
		Def: tools.Def{
			Name:        "delete_file",
			Description: "Delete a single file. Cannot delete directories.",
			Parameters: []tools.Param{
				{Name: "path", Type: "string", Description: "Absolute path to the file to delete", Required: true},
			},
		},
		Exec: func(ctx context.Context, args map[string]any) tools.Result {
			path := tools.GetString(args, "path")
			if path == "" {
				return tools.Result{Err: fmt.Errorf("delete_file: path is required")}
			}

			absPath, err := filepath.Abs(path)
			if err != nil {
				return tools.Result{Err: fmt.Errorf("delete_file: %w", err)}
			}

			if err := validateWritePath(absPath, cfg.AllowedPaths, cfg.ReadOnly); err != nil {
				return tools.Result{Err: err}
			}

			// Stat the file to ensure it exists and is not a directory.
			info, err := os.Stat(absPath)
			if err != nil {
				return tools.Result{Err: fmt.Errorf("delete_file: %w", err)}
			}
			if info.IsDir() {
				return tools.Result{Err: fmt.Errorf("delete_file: %q is a directory, only files can be deleted", absPath)}
			}

			if err := os.Remove(absPath); err != nil {
				return tools.Result{Err: fmt.Errorf("delete_file: %w", err)}
			}

			return tools.Result{Output: fmt.Sprintf("deleted %s", absPath)}
		},
	}
}