package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"os/exec"
	"path/filepath"

	"github.com/jung-kurt/gofpdf"
	"gopkg.in/yaml.v2"
)

// Metadata type
type Metadata struct {
	InvoiceNr    string
	InvoiceInfo  string
	InvoiceDdate string
	Vat          float64
	Account      string
	DueDate      string
}

// Address type
type Address struct {
	Name   string
	Street string
	Zip    string
	City   string
	TelNo  string
	Email  string
}

// InvoiceItem type
type InvoiceItem struct {
	Text        string
	Quantity    float64
	PicePerUnit float64
}

// InvoiceData type
type InvoiceData struct {
	Metadata       Metadata
	SenderAddress  Address
	BillingAddress Address
	Item           []InvoiceItem
}

/* global variable declaration */
var pdf *gofpdf.Fpdf
var yPos float64
var invoiceData InvoiceData
var progDir string

const marginTop = 7
const logoTop = 6
const logoHeight = 20
const lineSpacing = 5
const addressTop = 50
const line1Top = 100
const tabstopLeft = 20
const tabstopLeftAlt = 32
const tabstopAddress = 120
const tabstopCount = 10
const tabstopPrice = 10
const tabstopTotal = 170
const tabstopLogo = 155
const tabstopRight = 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), &invoiceData)
	if err != nil {
		log.Fatalf("error: %v", err)
	}

	fmt.Printf("--- t:\n%v\n\n", invoiceData)
	fmt.Printf("%s\n", invoiceData.BillingAddress.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()
	yPos = marginTop
	pdf.SetFont("Dejavusans-Bold", "", 10)
	writeText(tabstopLeft, yPos, "nbit Informatik GmbH")
	pdf.SetFont("Dejavusans", "", 10)
	yPos = yPos + lineSpacing
	writeText(tabstopLeft, yPos, "Kirchweg 2")
	yPos = yPos + lineSpacing
	writeText(tabstopLeft, yPos, "3510 Konolfingen")
	yPos = yPos + lineSpacing
	yPos = yPos + lineSpacing
	writeText(tabstopLeft, yPos, "Tel.")
	writeText(tabstopLeftAlt, yPos, "+41 31 792 00 40")
	yPos = yPos + lineSpacing
	writeText(tabstopLeft, yPos, "EMail")
	writeText(tabstopLeftAlt, yPos, "joerg.lehmann@nbit.ch")
	yPos = yPos + lineSpacing

	opt.ImageType = "png"
	opt.ReadDpi = true
	pdf.ImageOptions("logos/nbit-logo.png", tabstopLogo, logoTop, 0, logoHeight, false, opt, 0, "")
}

func printAddress() {
	fmt.Printf("Blabla: %s\n", invoiceData.BillingAddress.Name)
	yPos = addressTop
	writeText(tabstopAddress, yPos, invoiceData.BillingAddress.Name)
	yPos = yPos + lineSpacing
	writeText(tabstopAddress, yPos, invoiceData.BillingAddress.Street)
	yPos = yPos + lineSpacing
	writeText(tabstopAddress, yPos, invoiceData.BillingAddress.Zip+" "+invoiceData.BillingAddress.City)
	yPos = yPos + lineSpacing

	pdf.Line(tabstopLeft, line1Top, tabstopRight, line1Top)
}

func printQR() {
	var opt gofpdf.ImageOptions

	cmd := exec.Command(filepath.Join(progDir, "qrbill.sh"),
		"--account", invoiceData.Metadata.Account,
		"--amount", "123.00",
		"--creditor-name", invoiceData.SenderAddress.Name,
		"--creditor-street", invoiceData.SenderAddress.Street,
		"--creditor-postalcode", invoiceData.SenderAddress.Zip,
		"--creditor-city", invoiceData.SenderAddress.City,
		"--extra-infos", invoiceData.Metadata.InvoiceInfo,
		"--debtor-name", invoiceData.BillingAddress.Name,
		"--debtor-street", invoiceData.BillingAddress.Street,
		"--debtor-postalcode", invoiceData.BillingAddress.Zip,
		"--debtor-city", invoiceData.BillingAddress.City,
		"--due-date", invoiceData.Metadata.DueDate,
		"--language", "de")
	cmd.Env = append(os.Environ(),
		"INVNO="+invoiceData.Metadata.InvoiceNr,
	)
	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/"+invoiceData.Metadata.InvoiceNr+".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)
	}
	progDir = 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(progDir, "output", invoiceData.Metadata.InvoiceNr+".pdf"))
	if err == nil {
		fmt.Printf("Successfully created invoice\n")
	} else {
		fmt.Printf("Error: %v\n", err)
	}
}