package main

import (
	"fmt"
	"github.com/jung-kurt/gofpdf"
	"gopkg.in/yaml.v2"
	"io/ioutil"
	"log"
	"os"
	"os/exec"
	"path/filepath"
)

type Metadata struct {
	Invoice_nr   string
	Invoice_info string
	Invoice_date string
	Vat          float64
	Account      string
	Due_date     string
}

type Address struct {
	Name   string
	Street string
	Zip    string
	City   string
	Tel_no string
	Email  string
}

type InvoiceItem struct {
	Text          string
	Quantity      float64
	Pice_per_unit float64
}

type InvoiceData struct {
	Metadata        Metadata
	Sender_address  Address
	Billing_address Address
	Item            []InvoiceItem
}

/* global variable declaration */
var pdf *gofpdf.Fpdf
var y_pos float64
var invoice_data InvoiceData
var prog_dir string

const margin_top = 7
const logo_top = 6
const logo_height = 20
const line_spacing = 5
const address_top = 50
const line1_top = 100
const tabstop_left = 20
const tabstop_left_2 = 32
const tabstop_address = 120
const tabstop_count = 10
const tabstop_price = 10
const tabstop_total = 170
const tabstop_logo = 155
const tabstop_right = 200

func ReadInvoiceData(filename string) {
	data, err := ioutil.ReadFile(filename)
	if err != nil {
		log.Fatal(err)
	}

	//fmt.Printf("File contents: %s", data)

	err = yaml.Unmarshal([]byte(data), &invoice_data)
	if err != nil {
		log.Fatalf("error: %v", err)
	}

	fmt.Printf("--- t:\n%v\n\n", invoice_data)
	fmt.Printf("%s\n", invoice_data.Billing_address.Name)
}

func WriteText(x float64, y float64, text string, alignStr ...string) {
	tr := pdf.UnicodeTranslatorFromDescriptor("")
	align := "LT"
	if len(alignStr) > 0 {
		align = alignStr[0]
	}
	pdf.SetXY(x, y)
	pdf.CellFormat(0, 11, tr(text), "", 0, align, false, 0, "")
}

func SetupInvoice() {
	pdf = gofpdf.New("P", "mm", "A4", "")
	pdf.SetMargins(0, 0, 0)
	pdf.SetFontLocation("fonts")
	pdf.AddFont("Dejavusans", "", "DejaVuSans.json")
	pdf.AddFont("Dejavusans-Bold", "", "DejaVuSans-Bold.json")
	pdf.SetFont("Dejavusans", "", 10)
}

func PrintPageHeader(firstPage bool) {
	var opt gofpdf.ImageOptions

	pdf.AddPage()
	y_pos = margin_top
	pdf.SetFont("Dejavusans-Bold", "", 10)
	WriteText(tabstop_left, y_pos, "nbit Informatik GmbH")
	pdf.SetFont("Dejavusans", "", 10)
	y_pos = y_pos + line_spacing
	WriteText(tabstop_left, y_pos, "Kirchweg 2")
	y_pos = y_pos + line_spacing
	WriteText(tabstop_left, y_pos, "3510 Konolfingen")
	y_pos = y_pos + line_spacing
	y_pos = y_pos + line_spacing
	WriteText(tabstop_left, y_pos, "Tel.")
	WriteText(tabstop_left_2, y_pos, "+41 31 792 00 40")
	y_pos = y_pos + line_spacing
	WriteText(tabstop_left, y_pos, "EMail")
	WriteText(tabstop_left_2, y_pos, "joerg.lehmann@nbit.ch")
	y_pos = y_pos + line_spacing

	opt.ImageType = "png"
	opt.ReadDpi = true
	pdf.ImageOptions("logos/nbit-logo.png", tabstop_logo, logo_top, 0, logo_height, false, opt, 0, "")
}

func PrintAddress() {
	fmt.Printf("Blabla: %s\n", invoice_data.Billing_address.Name)
	y_pos = address_top
	WriteText(tabstop_address, y_pos, invoice_data.Billing_address.Name)
	y_pos = y_pos + line_spacing
	WriteText(tabstop_address, y_pos, invoice_data.Billing_address.Street)
	y_pos = y_pos + line_spacing
	WriteText(tabstop_address, y_pos, invoice_data.Billing_address.Zip+" "+invoice_data.Billing_address.City)
	y_pos = y_pos + line_spacing

	pdf.Line(tabstop_left, line1_top, tabstop_right, line1_top)
}

func PrintQR() {
	var opt gofpdf.ImageOptions

	cmd := exec.Command(filepath.Join(prog_dir, "qrbill.sh"),
		"--account", invoice_data.Metadata.Account,
		"--amount", "123.00",
		"--creditor-name", invoice_data.Sender_address.Name,
		"--creditor-street", invoice_data.Sender_address.Street,
		"--creditor-postalcode", invoice_data.Sender_address.Zip,
		"--creditor-city", invoice_data.Sender_address.City,
		"--extra-infos", invoice_data.Metadata.Invoice_info,
		"--debtor-name", invoice_data.Billing_address.Name,
		"--debtor-street", invoice_data.Billing_address.Street,
		"--debtor-postalcode", invoice_data.Billing_address.Zip,
		"--debtor-city", invoice_data.Billing_address.City,
		"--due-date", invoice_data.Metadata.Due_date,
		"--language", "de")
	cmd.Env = append(os.Environ(),
		"INVNO="+invoice_data.Metadata.Invoice_nr,
	)
	stdoutStderr, err := cmd.CombinedOutput()
	fmt.Printf("%s\n", stdoutStderr)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Printf("%s\n", stdoutStderr)

	opt.ImageType = "jpeg"
	opt.ReadDpi = true
	pdf.ImageOptions("qr-images/"+invoice_data.Metadata.Invoice_nr+".jpg", 0, 200, 0, 0, false, opt, 0, "")
}

func main() {
	dir, err := filepath.Abs(filepath.Dir(os.Args[0]))
	if err != nil {
		log.Fatal(err)
	}
	prog_dir = dir

	if len(os.Args) != 2 {
		fmt.Printf("usage: mkinvoice <yaml-file>\n")
		os.Exit(1)
	}

	ReadInvoiceData(os.Args[1])
	SetupInvoice()
	PrintPageHeader(true)
	PrintAddress()
	PrintQR()

	err = pdf.OutputFileAndClose(filepath.Join(prog_dir, "output", invoice_data.Metadata.Invoice_nr+".pdf"))
	if err == nil {
		fmt.Printf("Successfully created invoice\n")
	} else {
		fmt.Printf("Error: %v\n", err)
	}
}