/*
 * This file is subject to the terms and conditions defined in
 * file 'LICENSE.md', which is part of this source code package.
 */

package fjson

import (
	"bytes"
	"encoding/json"
	"os"
	"strconv"
	"strings"
	"testing"

	"github.com/stretchr/testify/require"
	"github.com/unidoc/unipdf/v3/model"
)

func TestLoadPDFFormData(t *testing.T) {
	fdata, err := LoadFromPDFFile(`./testdata/basicform.pdf`)
	if err != nil {
		t.Fatalf("Error: %v", err)
	}

	data, err := fdata.JSON()
	if err != nil {
		t.Fatalf("Error: %v", err)
	}

	var fields []struct {
		Name    string   `json:"name"`
		Value   string   `json:"value"`
		Options []string `json:"options"`
	}

	err = json.Unmarshal([]byte(data), &fields)
	if err != nil {
		t.Fatalf("Error: %v", err)
	}

	if len(fields) != 9 {
		t.Fatalf("Should have 9 fields")
	}

	// Check first field.
	if fields[0].Name != "full_name" {
		t.Fatalf("Incorrect field name (got %s)", fields[0].Name)
	}
	if fields[0].Value != "" {
		t.Fatalf("Value not empty")
	}
	if len(fields[0].Options) != 0 {
		t.Fatalf("Options not empty")
	}

	// Check another field.
	if fields[7].Name != "female" {
		t.Fatalf("Incorrect field name (got %s)", fields[7].Name)
	}
	if fields[7].Value != "Off" {
		t.Fatalf("Value not Off (got %s)", fields[7].Value)
	}
	if strings.Join(fields[7].Options, ", ") != "Off, Yes" {
		t.Fatalf("Wrong options (got %#v)", fields[7].Options)
	}
}

// Tests loading JSON form data, filling in a form and loading the PDF form data and comparing the results.
func TestFillPDFForm(t *testing.T) {
	fdata, err := LoadFromJSONFile(`./testdata/formdata.json`)
	if err != nil {
		t.Fatalf("Error: %v", err)
	}
	data, err := fdata.JSON()
	if err != nil {
		t.Fatalf("Error: %v", err)
	}

	// Open pdf to fill.
	var pdfReader *model.PdfReader
	{
		f, err := os.Open(`./testdata/basicform.pdf`)
		if err != nil {
			t.Fatalf("Error: %v", err)
		}
		defer f.Close()
		pdfReader, err = model.NewPdfReader(f)
		if err != nil {
			t.Fatalf("Error: %v", err)
		}
	}

	err = pdfReader.AcroForm.Fill(fdata)
	if err != nil {
		t.Fatalf("Error: %v", err)
	}

	// Write to buffer.
	var buf bytes.Buffer
	{
		// TODO(gunnsth): Implement a simpler method for populating all pages from a reader.
		pdfWriter := model.NewPdfWriter()
		for i := range pdfReader.PageList {
			err := pdfWriter.AddPage(pdfReader.PageList[i])
			if err != nil {
				t.Fatalf("Error: %v", err)
			}
		}
		err := pdfWriter.SetForms(pdfReader.AcroForm)
		if err != nil {
			t.Fatalf("Error: %v", err)
		}
		err = pdfWriter.Write(&buf)
		if err != nil {
			t.Fatalf("Error: %v", err)
		}
	}

	bufReader := bytes.NewReader(buf.Bytes())

	// Read back.
	fdata2, err := LoadFromPDF(bufReader)
	if err != nil {
		t.Fatalf("Error: %v", err)
	}

	data2, err := fdata2.JSON()
	if err != nil {
		t.Fatalf("Error: %v", err)
	}

	if data != data2 {
		t.Fatalf("%s != %s", data, data2)
	}
}

func TestJSONExtractAndFill(t *testing.T) {
	inputFilePath := "./testdata/advancedform.pdf"

	// Export JSON template from PDF.
	fieldData, err := LoadFromPDFFile(inputFilePath)
	require.NoError(t, err)
	jsonData, err := fieldData.JSON()
	require.NoError(t, err)

	// Load expected template from JSON file.
	fieldDataExp, err := LoadFromJSONFile("./testdata/advancedform.json")
	require.NoError(t, err)
	jsonDataExp, err := fieldDataExp.JSON()

	// Check templates for equality.
	require.Equal(t, jsonDataExp, jsonData)

	// Unmarshal and set template test field data.
	var fields []*struct {
		Name    string   `json:"name"`
		Value   string   `json:"value"`
		Options []string `json:"options"`
	}
	err = json.Unmarshal([]byte(jsonDataExp), &fields)
	require.NoError(t, err)

	// Some fields in the input file are read-only. Skip those.
	readOnlyMap := map[int]struct{}{
		0: {}, 1: {}, 28: {}, 29: {}, 30: {}, 38: {}, 46: {}, 54: {}, 62: {}, 79: {},
	}

	for i, field := range fields {
		if _, ok := readOnlyMap[i]; ok {
			continue
		}

		if len(field.Options) > 0 {
			field.Value = field.Options[1]
		} else {
			field.Value = strconv.Itoa(i)
		}
	}

	// Generate expected filled JSON data.
	jsonBytes, err := json.Marshal(fields)
	require.NoError(t, err)
	fieldDataExp, err = LoadFromJSON(bytes.NewReader(jsonBytes))
	require.NoError(t, err)
	jsonDataExp, err = fieldDataExp.JSON()

	// Fill test PDF form fields and write to buffer.
	f, err := os.Open(inputFilePath)
	require.NoError(t, err)
	defer f.Close()

	reader, err := model.NewPdfReader(f)
	require.NoError(t, err)

	err = reader.AcroForm.Fill(fieldDataExp)
	require.NoError(t, err)

	var buf bytes.Buffer
	writer := model.NewPdfWriter()
	for i := range reader.PageList {
		err := writer.AddPage(reader.PageList[i])
		require.NoError(t, err)
	}

	err = writer.SetForms(reader.AcroForm)
	require.NoError(t, err)
	err = writer.Write(&buf)
	require.NoError(t, err)

	// Load field data from buffer.
	fieldData, err = LoadFromPDF(bytes.NewReader(buf.Bytes()))
	require.NoError(t, err)
	jsonData, err = fieldData.JSON()

	// Check field data for equality.
	require.Equal(t, jsonDataExp, jsonData)
}