grokify/mogo

package csvutil

import (
    "encoding/csv"
    "io"
    "os"

    "github.com/grokify/mogo/type/stringsutil"
)

// Writer is a struct for a CSV/TSV writer.
type Writer struct {
    Separator        string
    StripRepeatedSep bool
    ReplaceSeparator bool
    SeparatorAlt     string
    File             *os.File
}

// NewWriter returns a Writer with the separator params set.
func NewWriter(filepath, sep string, replaceSeparator bool, alt string) (Writer, error) {
    w := Writer{
        Separator:        sep,
        StripRepeatedSep: false,
        ReplaceSeparator: replaceSeparator,
        SeparatorAlt:     alt}
    return w, w.open(filepath)
}

// Open opens a filepath.
func (w *Writer) open(filepath string) error {
    f, err := os.Create(filepath)
    if err != nil {
        return err
    }
    w.File = f
    return nil
}

// AddLine adds an `any` to the file.
func (w *Writer) AddLine(cells []any) error {
    _, err := w.File.WriteString(
        stringsutil.JoinInterface(
            cells, w.Separator, false, w.ReplaceSeparator, w.SeparatorAlt) + "\n")
    if err != nil {
        return err
    }
    return w.File.Sync()
}

// Close closes the file.
func (w *Writer) Close() error {
    return w.File.Close()
}

func NewWriterFile(filename string) (*csv.Writer, *os.File, error) {
    file, err := os.Create(filename)
    if err != nil {
        return nil, file, err
    }
    //defer file.Close()

    writer := csv.NewWriter(file)
    //defer writer.Flush()
    return writer, file, nil
}

// WriteCSVFiltered filters an existing CSV and writes the matching lines
// to a *csv.Writer.
func WriteCSVFiltered(reader *csv.Reader, writer *csv.Writer, andFilter map[string]stringsutil.MatchInfo, writeHeader bool) error {
    csvHeader := CSVHeader{}
    i := -1
    for {
        line, err := reader.Read()
        if err == io.EOF {
            break
        } else if err != nil {
            return err
        }
        i += 1
        if i == 0 {
            csvHeader.Columns = line
            if writeHeader {
                err := writer.Write(line)
                if err != nil {
                    return err
                }
            }
            continue
        }
        match, err := csvHeader.RecordMatch(line, andFilter)
        if err != nil {
            return err
        }
        if match {
            err := writer.Write(line)
            if err != nil {
                return err
            }
        }
    }
    return nil
}

// WriteFile writes a `[][]string` to a file.
func WriteFile(filename string, rows [][]string) error {
    c, f, err := NewWriterFile(filename)
    if err != nil {
        return err
    }
    defer f.Close()
    err = c.WriteAll(rows)
    if err != nil {
        return err
    }
    return f.Sync()
}