// Copyright (c) 2026 Probo Inc <hello@getprobo.com>.
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.

package esign

import (
	"bytes"
	"fmt"

	"github.com/pdfcpu/pdfcpu/pkg/api"
	"github.com/pdfcpu/pdfcpu/pkg/pdfcpu/types"
)

func StampSignatureID(pdfData []byte, signatureID string) ([]byte, error) {
	text := fmt.Sprintf("Electronic Signature ID: %s", signatureID)
	desc := "fontname:Helvetica, points:9, pos:tl, rot:0, op:1.0, scale:1.0 abs, color:0.3 0.3 0.3, offset:10 -10"

	wm, err := api.TextWatermark(text, desc, true, false, types.POINTS)
	if err != nil {
		return nil, fmt.Errorf("cannot create signature ID stamp: %w", err)
	}

	reader := bytes.NewReader(pdfData)
	var buf bytes.Buffer

	if err := api.AddWatermarks(reader, &buf, nil, wm, nil); err != nil {
		return nil, fmt.Errorf("cannot stamp signature ID on PDF: %w", err)
	}

	return buf.Bytes(), nil
}