package lib

import (
	"bytes"
	"errors"
	"fmt"
	"os"
	"path"
	"path/filepath"
	"strings"

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

func AppendToPdf(inputPdfFilePath string, inputXmlFilePath string, outputFilePath string) error {
	logger := GetDebugLogger()
	logger.Log(fmt.Sprintf("enter appendToPdf(%s, %s, %s)", inputPdfFilePath, inputXmlFilePath, outputFilePath))
	defer func() {
		logger.Log("leave appendToPdf")
	}()

	if inputPdfFilePath == "" {
		return errors.New("no input pdf file specified")
	}

	if inputXmlFilePath == "" {
		inputXmlFilePath = strings.TrimSuffix(inputPdfFilePath, filepath.Ext(inputPdfFilePath)) + ".xml"
	}

	if outputFilePath == "" {
		outputFilePath = strings.TrimSuffix(
			inputPdfFilePath,
			filepath.Ext(inputPdfFilePath),
		) + "_xml.pdf"
	}

	logger.Log(
		fmt.Sprintf(
			"pdfInput: '%s' xmlInput: '%s' output: '%s'",
			inputPdfFilePath,
			inputXmlFilePath,
			outputFilePath,
		),
	)

	inputFile, err := os.Open(inputPdfFilePath)
	if err != nil {
		return err
	}
	defer inputFile.Close()

	dest := bytes.Buffer{}

	err = api.AddAttachments(
		inputFile,
		&dest,
		[]string{inputXmlFilePath},
		true,
		model.NewDefaultConfiguration(),
	)
	if err != nil {
		return err
	}

	source := bytes.NewReader(dest.Bytes())
	dest = bytes.Buffer{}

	err = api.AddProperties(source, &dest, map[string]string{
		"DocumentFileName":           path.Base(inputXmlFilePath),
		"DocumentType":               "INVOICE",
		"ConformanceLevel":           "EN 16931",
		"SchemasSchema":              "Factur-X PDFA Extension Schema",
		"SchemasPrefix":              "fx",
		"SchemasPropertyName":        "DocumentFileName",
		"SchemasPropertyValueType":   "Text",
		"SchemasPropertyCategory":    "external",
		"SchemasPropertyDescription": "The name of the embedded XML document",
	}, model.NewDefaultConfiguration())
	if err != nil {
		return err
	}

	var outputFile *os.File
	outputFile, err = os.Create(outputFilePath)
	if err != nil {
		return err
	}
	defer outputFile.Close()

	_, err = outputFile.Write(dest.Bytes())
	if err != nil {
		return err
	}

	return nil
}