frontend/src/csv.js

export const CSV_SEPARATOR = ';'

function formatCsvNumber(value) {
  if (typeof value !== 'number' || !Number.isFinite(value)) return ''
  const normalized = Object.is(value, -0) ? 0 : value
  return normalized.toLocaleString('pt-BR', {
    useGrouping: false,
    maximumFractionDigits: 15,
  })
}

export function toCsvCell(value, separator = CSV_SEPARATOR) {
  let text = ''

  if (typeof value === 'number') {
    text = formatCsvNumber(value)
  } else if (value instanceof Date) {
    text = Number.isNaN(value.getTime()) ? '' : value.toISOString()
  } else {
    text = String(value ?? '')
  }

  const escaped = text.replace(/"/g, '""')
  if (escaped.includes('"') || escaped.includes('\n') || escaped.includes('\r') || escaped.includes(separator)) {
    return `"${escaped}"`
  }
  return escaped
}

export function buildCsvBlob(columns, rows, separator = CSV_SEPARATOR) {
  if (!Array.isArray(columns) || columns.length === 0) return null

  const header = columns.map((col) => toCsvCell(col, separator)).join(separator)
  const lines = [header]

  ;(rows || []).forEach((row) => {
    const values = columns.map((col, index) => {
      if (Array.isArray(row)) return toCsvCell(row[index], separator)
      return toCsvCell(row?.[col], separator)
    })
    lines.push(values.join(separator))
  })

  const csv = `\uFEFF${lines.join('\n')}`
  return new Blob([csv], { type: 'text/csv;charset=utf-8;' })
}

export function tableToCsvBlob(table, separator = CSV_SEPARATOR) {
  if (!table || !Array.isArray(table.columns) || !Array.isArray(table.rows) || table.columns.length === 0) return null
  return buildCsvBlob(table.columns, table.rows, separator)
}