package main

import (
	"fmt"
	"github.com/jung-kurt/gofpdf"
)

type Adress struct {
	lines []string
}

type Item struct {
	text string
	count float64
	price float64
}

type InvoiceData struct {
	invoice_number string
	invoice_date string
	address Adress
	items []Item
	invoice_total_net float64
	invoice_mwst float64
	invoice_total float64
}

/* global variable declaration */
var pdf *gofpdf.Fpdf
var y_pos float64
var invoice_data InvoiceData
const margin_top = 7
const logo_top = 6
const logo_height = 23
const line_spacing = 4
const tabstop_left = 20
const tabstop_left_2 = 32
const tabstop_address = 10
const tabstop_count = 10
const tabstop_price = 10
const tabstop_total = 170
const tabstop_logo = 155

func ReadInvoiceData(filename string) {
	invoice_data.invoice_number = "1"
	invoice_data.invoice_date = "01.01.2021"
	invoice_data.address = Adress{ []string{"Jörg Lehmann", "Kirchweg 2", "3510 Konolfingen" }}
	invoice_data.items = []Item{ Item{ "Item 1",1,10 }, Item{"Text only",0,0 } }
	invoice_data.invoice_total_net = 100
	invoice_data.invoice_mwst = 10
	invoice_data.invoice_total = 110
}

func WriteText(x float64, y float64, text string, alignStr ...string) {
	align := "LT"
	if len(alignStr) > 0 {
		align = alignStr[0]
	}
	pdf.SetXY(x, y)
	pdf.CellFormat(0, 10, 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", "", 9)
}

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

	pdf.AddPage()
	y_pos = margin_top
	pdf.SetFont("Dejavusans-Bold", "", 9)
	WriteText(tabstop_left, y_pos, "nbit Informatik GmbH")
	pdf.SetFont("Dejavusans", "", 9)
	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 main() {
	SetupInvoice()
	PrintPageHeader(true)

	err := pdf.OutputFileAndClose("hello.pdf")
	if err == nil {
		fmt.Printf("Successfully created invoice\n")
	} else {
		fmt.Printf("Error: %v\n", err)
	}
}