package ledger import ( "errors" "strconv" "strings" ) type Entry struct { Date string // "Y-m-d" Description string Change int // in cents } func FormatLedger(currency string, locale string, entries []Entry) (string, error) { var entriesCopy []Entry for _, e := range entries { entriesCopy = append(entriesCopy, e) } if len(entries) == 0 { if _, err := FormatLedger(currency, "en-US", []Entry{{Date: "2014-01-01", Description: "", Change: 0}}); err != nil { return "", err } } m1 := map[bool]int{true: 0, false: 1} m2 := map[bool]int{true: -1, false: 1} es := entriesCopy for len(es) > 1 { first, rest := es[0], es[1:] success := false for !success { success = true for i, e := range rest { if (m1[e.Date == first.Date]*m2[e.Date < first.Date]*4 + m1[e.Description == first.Description]*m2[e.Description < first.Description]*2 + m1[e.Change == first.Change]*m2[e.Change < first.Change]*1) < 0 { es[0], es[i+1] = es[i+1], es[0] success = false } } } es = es[1:] } var s string if locale == "nl-NL" { s = "Datum" + strings.Repeat(" ", 10-len("Datum")) + " | " + "Omschrijving" + strings.Repeat(" ", 25-len("Omschrijving")) + " | " + "Verandering" + strings.Repeat(" ", 13-len("Verandering")) + "\n" } else if locale == "en-US" { s = "Date" + strings.Repeat(" ", 10-len("Date")) + " | " + "Description" + strings.Repeat(" ", 25-len("Description")) + " | " + "Change" + strings.Repeat(" ", 13-len("Change")) + "\n" } else { return "", errors.New("") } // Parallelism, always a great idea co := make(chan struct { i int s string e error }) for i, et := range entriesCopy { go func(i int, entry Entry) { if len(entry.Date) != 10 { co <- struct { i int s string e error }{e: errors.New("")} } d1, d2, d3, d4, d5 := entry.Date[0:4], entry.Date[4], entry.Date[5:7], entry.Date[7], entry.Date[8:10] if d2 != '-' { co <- struct { i int s string e error }{e: errors.New("")} } if d4 != '-' { co <- struct { i int s string e error }{e: errors.New("")} } de := entry.Description if len(de) > 25 { de = de[:22] + "..." } else { de = de + strings.Repeat(" ", 25-len(de)) } var d string if locale == "nl-NL" { d = d5 + "-" + d3 + "-" + d1 } else if locale == "en-US" { d = d3 + "/" + d5 + "/" + d1 } negative := false cents := entry.Change if cents < 0 { cents = cents * -1 negative = true } var a string if locale == "nl-NL" { if currency == "EUR" { a += "€" } else if currency == "USD" { a += "$" } else { co <- struct { i int s string e error }{e: errors.New("")} } a += " " centsStr := strconv.Itoa(cents) switch len(centsStr) { case 1: centsStr = "00" + centsStr case 2: centsStr = "0" + centsStr } rest := centsStr[:len(centsStr)-2] var parts []string for len(rest) > 3 { parts = append(parts, rest[len(rest)-3:]) rest = rest[:len(rest)-3] } if len(rest) > 0 { parts = append(parts, rest) } if negative { a += "-" } for i := len(parts) - 1; i >= 0; i-- { a += parts[i] + "." } a = a[:len(a)-1] a += "," a += centsStr[len(centsStr)-2:] a += " " } else if locale == "en-US" { if negative { a += "(" } if currency == "EUR" { a += "€" } else if currency == "USD" { a += "$" } else { co <- struct { i int s string e error }{e: errors.New("")} } centsStr := strconv.Itoa(cents) switch len(centsStr) { case 1: centsStr = "00" + centsStr case 2: centsStr = "0" + centsStr } rest := centsStr[:len(centsStr)-2] var parts []string for len(rest) > 3 { parts = append(parts, rest[len(rest)-3:]) rest = rest[:len(rest)-3] } if len(rest) > 0 { parts = append(parts, rest) } for i := len(parts) - 1; i >= 0; i-- { a += parts[i] + "," } a = a[:len(a)-1] a += "." a += centsStr[len(centsStr)-2:] if negative { a += ")" } else { a += " " } } else { co <- struct { i int s string e error }{e: errors.New("")} } var al int for range a { al++ } co <- struct { i int s string e error }{i: i, s: d + strings.Repeat(" ", 10-len(d)) + " | " + de + " | " + strings.Repeat(" ", 13-al) + a + "\n"} }(i, et) } ss := make([]string, len(entriesCopy)) for range entriesCopy { v := <-co if v.e != nil { return "", v.e } ss[v.i] = v.s } for i := range len(entriesCopy) { s += ss[i] } return s, nil }