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")
// 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")

// 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"`
}

// 'global' data
var data ParsedData

func main() {

	// 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))

	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:
			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,}
			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 {
		// ... and all the accounts involved
		for tsc := range data.Trn[tc].Spl {
			aid := data.Trn[tc].Spl[tsc].AccountId
			if check_trn(&data.Trn[tc],accnt,aid) == false {
				ac := accnt[aid].num
				fmt.Println("  ",data.Trn[tc].Date)
				fmt.Println("  ",data.Trn[tc].Description)
				fmt.Println("  ",data.Accnt[ac].Name)
				fmt.Println("")
			}
		}
	}

}

func check_trn(ta *Transaction,accnt map[string]amap,aid string) bool {
	//ac := accnt[aid].num
	if accnt[aid].rid[0]=="NONE" {
		return true
	}
	for ra := range accnt[aid].rid {
		for ea := range ta.Spl {
			oaid := ta.Spl[ea].AccountId
			switch {
			case accnt[aid].tax && accnt[aid].buy:
				// check pids
				if accnt[oaid].pid == accnt[aid].rid[ra] {
					return check_vals(accnt,aid,oaid,ta)
				}
			default:
				// check aids
				if ta.Spl[ea].AccountId == accnt[aid].rid[ra] {
					return check_vals(accnt,aid,oaid,ta)
				}
			}
			//fmt.Println(data.Accnt[accnt[oaid].num].Name)
		}
	}

	// some exceptions - transaction description
	desclist := []string{
		"GEMA",
		"Deutsche Post",
		"gesetz IHK",
		"Gesundheitsbelehrung",
		"Gewerbezentralregister",
		"Entgeltabrechnung siehe Anlage",
		"ENTGELT SPK",
		"ttenrecht und F",
	}
	for dc := range desclist {
		if strings.Contains(ta.Description,desclist[dc]){
			return true
		}
	}
	// some exceptions - account name
	accountlist := []string{
		"4970 Nebenkosten des",
	}
	anum := accnt[aid].num
	for ac := range accountlist {
		if strings.Contains(data.Accnt[anum].Name,accountlist[ac]){
			return true
		}
	}

	fmt.Println("E: No correpsonding account!")

	return false
}

func check_vals(accnt map[string]amap,aid string,oaid string,ta *Transaction) bool {
	qa, _ := strconv.Atoi(get_val(ta,aid))
	qb, _ := strconv.Atoi(get_val(ta,oaid))

	var val, cmp int


	switch {
	case accnt[aid].tax:
		// aid = taxval * oaid / 100
		val = int((qb*accnt[aid].taxval)/100.0)
		cmp = qa
	default:
		// oaid = taxval * aid / 100
		val = int((qa*accnt[aid].taxval)/100.0)
		cmp = qb
	}

	if cmp >= val-1 && cmp <= val+1 {
		return true
	} else {
		fmt.Println("E:",qa,qb,"<- ",accnt[aid].taxval,"->",cmp,val)
		return false
	}
}

func get_val(ta *Transaction,aid string) string {
	for sc := range ta.Spl {
		if ta.Spl[sc].AccountId == aid {
			return strings.TrimSuffix(ta.Spl[sc].Value,"/100")
		}
	}
	return ""
}

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