// Copyright (c) 2026 Probo Inc <hello@probo.com>.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// 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
}