package main

import (
	"encoding/xml"
	"fmt"
	"io/ioutil"
	"os"
	"strings"
	"strconv"
)

//
// hardcoded account ids we have to look at
//
// --- buy
// wareneingang 19% and 7%
const pid_buy_n = string("8e3b7c42e3173ed85f3d4736e82afb4d")
const pid_buy_s = string("0cfd2ceb45fff89b9d1b7ce3af66cdf3")
const pid_misc  = string("e3acc2865dbf931e41cf2b90240de5c2")
const pid_rep   = string("b1d04ad157cac569f4299d4ddf94ed6f")
const pid_room  = string("4394ed4ffa7266f8f8731080926a7a61")
const pid_cap   = string("4196ee026d1bdb785df2c975fca91ae0")
const aid_werbe = string("cb67d346eac01c2b66e2394df4e8d6e8")
// abziehbare vst 19% and 7%
const aid_vst_n = string("7c449e13125d6b93043f963628106db2")
const aid_vst_s = string("006643c1c0a91f2b40614c75a49c6295")
// --- sales
// receipts
const aid_rec_n = string("f3e905732b729ba096a50dab60559ce7")
const aid_rec_s = string("66c1b04bd897766cb2be538094e1db6a")
const aid_tip   = string("1d20024badc11a99a8e1cf3a9a64a501")
const aid_dep   = string("9772f4e231f6f5e3100132cc53eb3447")
// ust
const aid_ust_n = string("e4bd6ff52408be8076f24aeb105893d9")
const aid_ust_s = string("38bf40d16529f2a1e611c073c6c1dc9c")

type inv_accnts struct {
	id string
	taxval int
	tax bool
	buy bool
}

// make these account data the only one, above p/aids redundant!
// we have all the information in here!

var iaa []inv_accnts = []inv_accnts{
// wareneingang 19% and 7% (note: pids!)
 { "8e3b7c42e3173ed85f3d4736e82afb4d",19,false,true },
 { "0cfd2ceb45fff89b9d1b7ce3af66cdf3", 7,false,true },
 { "e3acc2865dbf931e41cf2b90240de5c2",19,false,true },
 { "b1d04ad157cac569f4299d4ddf94ed6f",19,false,true },
 { "4394ed4ffa7266f8f8731080926a7a61",19,false,true },
 { "4196ee026d1bdb785df2c975fca91ae0",19,false,true },
// aids ...
 { "cb67d346eac01c2b66e2394df4e8d6e8",19,false,true },
// abziehbare vst 19% and 7%
 { "7c449e13125d6b93043f963628106db2",19,true,true },
 { "006643c1c0a91f2b40614c75a49c6295", 7,true,true },
// --- sales
// receipts
 { "f3e905732b729ba096a50dab60559ce7",19,false,false },
 { "66c1b04bd897766cb2be538094e1db6a", 7,false,false },
 { "1d20024badc11a99a8e1cf3a9a64a501",19,false,false },
 { "9772f4e231f6f5e3100132cc53eb3447",19,false,false },
// ust
 { "e4bd6ff52408be8076f24aeb105893d9",19,true,false },
 { "38bf40d16529f2a1e611c073c6c1dc9c", 7,true,false },
}

// transacion exception list
var trn_exc = []string{
	"GEMA",
	"Deutsche Post",
	"gesetz IHK",
	"Gesundheitsbelehrung",
	"Gewerbezentralregister",
	"Entgeltabrechnung siehe Anlage",
	"ENTGELT SPK",
	"ttenrecht und F",
	"Unterrichtung Gastst",
}

// account exception list
var account_exc = []string{
	"4970 Nebenkosten des",
}

// account maps
type amap struct {
	pid string // parent id
	num int // account number
	taxval int // 7 or 19
	buy bool // buy or sales
	tax bool // tax or non-tax(=goods) account
	rid []string // required transaction account(s)
}

// xml
type Account struct {
	XMLName xml.Name `xml:"account"`
	Name string `xml:"name"`
	AccountId string `xml:"id"`
	ParentId string `xml:"parent"`
}
type Split struct {
	XMLName xml.Name `xml:"split"`
	Id string `xml:"id"`
	Value string `xml:"value"`
	Quantity string `xml:"quantity"`
	AccountId string `xml:"account"`
}
type Transaction struct {
	XMLName xml.Name `xml:"transaction"`
	Id string `xml:"id"`
	Date string `xml:"date-posted>date"`
	Description string `xml:"description"`
	Spl []Split `xml:"splits>split"`
}
type ParsedData struct {
	XMLName xml.Name `xml:"gnc-v2"`
	DataCnt []string `xml:"count-data"`
	Accnt []Account `xml:"book>account"`
	Trn []Transaction `xml:"book>transaction"`
}

// tax
type TaxReport struct {
	Expenses [2]int
	InputTax [2]int
	ExpExc [2]int
	ITExc [2]int
	Receipts [2]int
	SalesTax [2]int
}

// 'global' data
var data ParsedData
var tax_report TaxReport

func main() {

	// argv
	sel_date := ""
	if len(os.Args) > 1 {
		sel_date = os.Args[1]
	}

	// open xml file
	file, err := os.Open("c13_skr03.gnucash")
	if err != nil {
		fmt.Println("Error opening file:", err)
		return
	}
	defer file.Close()

	// read xml file
	xmldata, err := ioutil.ReadAll(file)
	if err != nil {
		fmt.Println("Error reading file:", err)
		return
	}

	// unmarshal xml data
	err = xml.Unmarshal(xmldata,&data)
	if err != nil {
		fmt.Println("Error unmarshaling xml data:", err)
		return
	}

	// whooha, this is our data!
	fmt.Println("Parsed accounts:",len(data.Accnt))
	fmt.Println("Parsed transactions:",len(data.Trn))
	fmt.Println("")

	accnt := make(map[string]amap)

	for ac := range data.Accnt {
		aid := data.Accnt[ac].AccountId
		pid := data.Accnt[ac].ParentId
		// general map
		rid := make ([]string,10,10)
		accnt[aid]=amap{
			pid,ac,0,false,false,rid,
		}
		rid[0]="NONE"
		tmp := accnt[aid]
		switch {
		// ---- buy
		//   -- goods
		case pid == pid_buy_n || pid == pid_misc || pid == pid_rep || pid == pid_room || pid == pid_cap || aid == aid_werbe:
			tmp.taxval=19
			tmp.buy=true
			rid[0]=aid_vst_n
			accnt[aid]=tmp
		case pid == pid_buy_s:
			tmp.taxval=7
			tmp.buy=true
			rid[0]=aid_vst_s
			accnt[aid]=tmp
		//   -- tax
		case aid == aid_vst_n:
			tmp.taxval=19
			tmp.buy=true
			tmp.tax=true
			rid=[]string{pid_buy_n,pid_misc,pid_rep,pid_room,pid_cap,aid_werbe,}
			accnt[aid]=tmp
		case aid == aid_vst_s:
			tmp.taxval=7
			tmp.buy=true
			tmp.tax=true
			rid[0]=pid_buy_s
			accnt[aid]=tmp
		// ---- sales ----
		//   -- receipts
		case aid == aid_rec_n || aid == aid_tip || aid == aid_dep:
			tmp.taxval=19
			rid[0]=aid_ust_n
			accnt[aid]=tmp
		case aid == aid_rec_s:
			tmp.taxval=7
			rid[0]=aid_ust_s
			accnt[aid]=tmp
		//   -- tax
		case aid == aid_ust_n:
			tmp.taxval=19
			tmp.tax=true
			rid=[]string{aid_rec_n,aid_tip,aid_dep,}
			accnt[aid]=tmp
		case aid == aid_ust_s:
			tmp.taxval=7
			tmp.tax=true
			rid[0]=aid_rec_s
			accnt[aid]=tmp
		}
	}

	// check transactions ...
	for tc := range data.Trn {
		// check balance ...
		check_balance(&data.Trn[tc],accnt,sel_date)
	}

	// tax report
	fmt.Println("Umsatzsteuervoranmeldung (19% | 7%):")
	fmt.Println("------------------------------------")
	fmt.Println("Aufwendungen:",tax_report.Expenses[0],
	                            tax_report.Expenses[1]);
	fmt.Println("ohne Ausn.  :",tax_report.Expenses[0]-
	                            tax_report.ExpExc[0],
	                            tax_report.Expenses[1]-
	                            tax_report.ExpExc[1]);
	fmt.Println("gesch. Vst. :",int((tax_report.Expenses[0]*19)/100.0),
	                            int((tax_report.Expenses[1]*7)/100.0))
	fmt.Println("ohne Ausn.  :",int(((tax_report.Expenses[0]-
	                                 tax_report.ExpExc[0])*19)/100.0),
	                            int(((tax_report.Expenses[1]-
	                                 tax_report.ExpExc[1])*7)/100.0))
	fmt.Println("Vorsteuer   :",tax_report.InputTax[0],
	                            tax_report.InputTax[1],
	            "->",tax_report.InputTax[0]+tax_report.InputTax[1]);
	fmt.Println("------------------------------------")
	fmt.Println("Einnahmen   :",-tax_report.Receipts[0],
	                            -tax_report.Receipts[1]);
	fmt.Println("gesch. Ust. :",int((-tax_report.Receipts[0]*19)/100.0),
	                            int((-tax_report.Receipts[1]*7)/100.0));
	fmt.Println("Umsatzsteuer:",-tax_report.SalesTax[0],
	                            -tax_report.SalesTax[1]);
	fmt.Println("------------------------------------")

}

func check_balance(ta *Transaction,accnt map[string]amap,sel_date string) bool {

	// check date
	tdate := strings.Fields(ta.Date)[0]
	if !strings.Contains(tdate,sel_date) {
		return true
	} else {
	}

	// [taxval: 19=0 7=1][tax: no=0 yes=1][buy: no=0 yes=1]
	var sum [2][2][2]int

	for sc := range ta.Spl {
		aid := ta.Spl[sc].AccountId
		//accnt[aid].tax
		for iac := range iaa {
			// taxval
			tv := int(0)
			if iaa[iac].taxval == 7 {
				tv = 1
			}
			// tax
			tax := int(0)
			if iaa[iac].tax {
				tax = 1
			}
			// buy
			buy := int(0)
			if iaa[iac].buy {
				buy = 1
			}
			// match! add to sum and break.
			match := bool(false)
			// check pids if ...
			if tax == 0 && buy == 1 {
				_, exists := accnt[aid]
				if exists {
					// pids
					if accnt[aid].pid == iaa[iac].id {
						match = true
					}
				}
			}
			// ... however, always check aids
			if aid == iaa[iac].id {
				match = true
			}
			if match {
				inc, _ := strconv.Atoi(strings.TrimSuffix(ta.Spl[sc].Value,"/100"))
				sum[tv][tax][buy] += inc
				break
			}
		}
	}

	// check for exceptions
	exc := false
	for ec := range trn_exc {
		if strings.Contains(ta.Description,trn_exc[ec]) {
			exc = true
			break
		}
	}
	//for ac := range accountlist {
	//	if strings.Contains(data.Accnt[anum].Name,accountlist[ac]){
	//		return true
	//	}
	//}

	// tax report
	for tv := 0; tv<2; tv++ {
		tax_report.Expenses[tv] += sum[tv][0][1]
		tax_report.InputTax[tv] += sum[tv][1][1]
		tax_report.Receipts[tv] += sum[tv][0][0]
		tax_report.SalesTax[tv] += sum[tv][1][0]
		if exc {
			tax_report.ExpExc[tv] += sum[tv][0][1]
			tax_report.ITExc[tv] += sum[tv][1][1]
		}
	}

	// check
	var expected [2]int
	check := true
	for buy := 0; buy < 2; buy++ {
		expected[0]=int((sum[0][0][buy]*19)/100.0)
		expected[1]=int((sum[1][0][buy]*7)/100.0)
		for tv :=0; tv < 2; tv++ {
			if expected[tv] < sum[tv][1][buy]-1 ||
			   expected[tv] > sum[tv][1][buy]+1 {
				var sb, st string
				if buy == 0 {
					sb = "Umsatzsteuer"
				} else {
					sb = "Vorsteuer"
				}
				if tv == 0 {
					st = "19%"
				} else {
					st = " 7%"
				}
				check = false
				fmt.Printf("%s %s: ",sb,st);
				fmt.Printf("Erwarte %d statt %d aus %d! ",
				           expected[tv],
				           sum[tv][1][buy],sum[tv][0][buy]);
				if(!exc) {
					fmt.Printf("\n");
				} else {
					fmt.Printf("Ausnahme greift!\n");
					fmt.Printf("(%s)\n\n",ta.Description)
				}
			}
		}
	}
	if !check && !exc {
		fmt.Println("am",ta.Date)
		fmt.Printf("(%s)\n",ta.Description)
		fmt.Println("Beteiligte Konten:")
		for ic := range ta.Spl {
			found := strings.TrimSuffix(ta.Spl[ic].Value,"/100")
			aid := ta.Spl[ic].AccountId
			_, exists := accnt[aid]
			if exists {
				num := accnt[aid].num
				fmt.Printf("  %s => %s\n",data.Accnt[num].Name,
				                          found)
			} else {
				fmt.Printf("  %s => %s\n",aid,found)
			}
		}
		fmt.Println("")
	}

	return check
}

func round(v float64) int {
	if v < 0.0 {
		v -= 0.5
	} else {
		v += 0.5
	}
	return int(v)
}