Transform csv lines

main.go

@@ -6,5 +6,5 @@ import (
 
 func main() {
 	fmt.Println("Hello World")
-
+	readDir()
 }

read_dir.go

@@ -0,0 +1,240 @@
+package main
+
+import (
+	"bufio"
+	"encoding/csv"
+	"errors"
+	"fmt"
+	"io"
+	"io/fs"
+	"log"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+)
+
+func readDir() {
+	files := findFiles()
+	for _, file := range files {
+		readFile(file)
+	}
+}
+
+func findFiles() []string {
+	var files []string
+	err := filepath.WalkDir(".", func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			fmt.Printf("prevent panic by handling failure accessing a path %q: %v\n", path, err)
+			return err
+		}
+
+		ext := filepath.Ext(d.Name())
+		if ext == ".csv" {
+			files = append(files, d.Name())
+		}
+
+		return nil
+	})
+
+	if err != nil {
+		fmt.Printf("error walking the path %q: %v\n", ".", err)
+		return nil
+	}
+
+	return files
+}
+
+func readFile(filename string) {
+	file, err := os.Open(filename)
+	if err != nil {
+		fmt.Printf("cannot open file %s", filename)
+	}
+	defer file.Close()
+
+	reader := csv.NewReader(bufio.NewReader(file))
+	reader.FieldsPerRecord = -1 // Disable record length test in the CSV
+	reader.LazyQuotes = true    // Allow quote in unquoted field
+
+	sections := ibkrSections()
+	var header []string
+	for {
+		line, err := reader.Read()
+		if err == io.EOF {
+			break
+		}
+
+		if err != nil {
+			continue
+		}
+
+		handle, ok := sections[line[0]]
+		if !ok {
+			continue
+		}
+
+		if line[1] == "Header" {
+			header = line
+			continue
+		}
+
+		lm, err := mapLine(line, header)
+		if err != nil {
+			continue
+		}
+
+		handle(lm)
+	}
+}
+
+type lineHandler func(map[string]string)
+
+func handleLine(m map[string]string) {
+	fmt.Println(m)
+}
+
+func ibkrSections() map[string]lineHandler {
+	return map[string]lineHandler{
+		"Financial Instrument Information": handleInstrumentLine,
+		"Trades":                           handleTradeLine,
+		"Dividends":                        handleDividendLine,
+		"Withholding Tax":                  handleWithholdingTaxLine,
+		"Fees":                             handleFeeLine,
+	}
+}
+
+func mapLine(data, header []string) (map[string]string, error) {
+	if header == nil {
+		return nil, errors.New("cannot convert to row from empty header")
+	}
+
+	if len(header) != len(data) {
+		return nil, errors.New("header and line length mismatch")
+	}
+
+	header[0], data[0] = "Section", header[0]
+
+	lm := make(map[string]string, len(data))
+	for pos, field := range header {
+		lm[field] = data[pos]
+	}
+
+	return lm, nil
+}
+
+func handleInstrumentLine(lm map[string]string) {
+	symbols := append(strings.Split(strings.ReplaceAll(lm["Symbol"], " ", ""), ","), formatISIN(lm["Security ID"]))
+	if len(symbols) == 0 {
+		return
+	}
+
+	fmt.Println(symbols, lm["Asset Category"])
+}
+
+// Adds "US" prefix to US security ISIN codes and removes the 12th check digit
+func formatISIN(sID string) string {
+	if sID == "" {
+		log.Fatal("empty security ID")
+	}
+
+	if len(sID) > 8 && len(sID) < 11 {
+		// US ISIN number. Add country code
+		sID = "US" + sID
+	}
+
+	if len(sID) == 12 {
+		// Remove ISIN check digit
+		sID = sID[:11]
+		return sID
+	}
+
+	return sID
+}
+
+func handleTradeLine(lm map[string]string) {
+	if lm["Date/Time"] == "" || lm["Asset Category"] == "Forex" || lm["Symbol"] == "" {
+		return
+	}
+	t := timeFromExact(lm["Date/Time"])
+	c := lm["Currency"]
+	fmt.Println(lm["Symbol"], c, t, amountFromString(lm["Quantity"]), amountFromString(lm["T. Price"]), amountFromString(lm["Comm/Fee"]))
+}
+func handleDividendLine(lm map[string]string) {
+	if lm["Date"] == "" {
+		return
+	}
+	symbol, err := symbolFromDescription(lm["Description"])
+	if err != nil {
+		return
+	}
+	fmt.Println(symbol, lm["Currency"], yearFromDate(lm["Date"]), amountFromString(lm["Amount"]), false)
+}
+
+func yearFromDate(s string) int {
+	y, err := strconv.Atoi(s[:4])
+	if err != nil {
+		return 0
+	}
+	return y
+}
+
+func handleWithholdingTaxLine(lm map[string]string) {
+	if lm["Date"] == "" {
+		return
+	}
+
+	symbol, err := symbolFromDescription(lm["Description"])
+	if err != nil {
+		return
+	}
+
+	fmt.Println(symbol, lm["Currency"], yearFromDate(lm["Date"]), amountFromString(lm["Amount"]), true)
+}
+func handleFeeLine(lm map[string]string) {
+	if lm["Date"] == "" {
+		return
+	}
+
+	fmt.Println(lm["Currency"], amountFromString(lm["Amount"]), yearFromDate(lm["Date"]))
+}
+
+func symbolFromDescription(d string) (string, error) {
+	if d == "" {
+		return "", errors.New("cannot create asset event without symbol")
+	}
+
+	// This is a dividend or withholding tax
+	parensIdx := strings.Index(d, "(")
+	if parensIdx == -1 {
+		return "", errors.New("cannot create asset event without symbol")
+	}
+
+	symbol := strings.ReplaceAll(d[:parensIdx], " ", "")
+	if symbol == "" {
+		return "", errors.New("cannor find symbol in description")
+	}
+	return symbol, nil
+}
+
+func amountFromString(s string) (v float64) {
+	if s == "" {
+		log.Fatalf("Cannot create amount from %s", s)
+	}
+	s = strings.ReplaceAll(s, ",", "")
+	v, err := strconv.ParseFloat(s, 64)
+	if err != nil {
+		log.Printf("error parsing float from from %v", err)
+	}
+	return
+}
+
+func timeFromExact(t string) time.Time {
+	timeStr := strings.Join(strings.Split(t, ","), "")
+	tm, err := time.Parse("2006-01-02 15:04:05", timeStr)
+	if err != nil {
+		panic(err)
+	}
+
+	return tm
+}