package text

import (
	"context"
	"errors"
	"strings"
)

var ErrEmptyInput = errors.New("batch input content cannot be empty")

type Line struct {
	RowNo int
	Text  string
}

type FieldLine struct {
	RowNo  int
	Fields []string
}

func ParseNonEmptyLines(ctx context.Context, input string) ([]Line, error) {
	lines := strings.Split(input, "\n")
	result := make([]Line, 0, len(lines))
	for index, line := range lines {
		if err := ctx.Err(); err != nil {
			return nil, err
		}
		value := strings.TrimSpace(line)
		if value == "" {
			continue
		}
		result = append(result, Line{
			RowNo: index + 1,
			Text:  value,
		})
	}
	if len(result) == 0 {
		return nil, ErrEmptyInput
	}
	return result, nil
}

func ParseWhitespaceFields(ctx context.Context, input string) ([]FieldLine, error) {
	lines, err := ParseNonEmptyLines(ctx, input)
	if err != nil {
		return nil, err
	}
	result := make([]FieldLine, 0, len(lines))
	for _, line := range lines {
		if err = ctx.Err(); err != nil {
			return nil, err
		}
		result = append(result, FieldLine{
			RowNo:  line.RowNo,
			Fields: strings.Fields(line.Text),
		})
	}
	return result, nil
}