param(
  [string]$RawDirectory = "$(Split-Path -Parent $PSScriptRoot)\data\raw\gansu\2024",
  [string]$OutputDirectory = "$(Split-Path -Parent $PSScriptRoot)\data\processed\gansu\2024\csv"
)

$ErrorActionPreference = 'Stop'
New-Item -ItemType Directory -Force -Path $OutputDirectory | Out-Null

$excel = New-Object -ComObject Excel.Application
$excel.Visible = $false
$excel.DisplayAlerts = $false
try {
  Get-ChildItem -LiteralPath $RawDirectory -Filter '*.xls' | ForEach-Object {
    $workbook = $excel.Workbooks.Open($_.FullName)
    try {
      $worksheet = $workbook.Worksheets.Item(1)
      $usedRange = $worksheet.UsedRange
      $matrix = $usedRange.Value2
      $rows = for ($row = 1; $row -le $usedRange.Rows.Count; $row++) {
        $record = [ordered]@{ row_number = $row }
        for ($column = 1; $column -le $usedRange.Columns.Count; $column++) {
          $record["col$column"] = $matrix[$row, $column]
        }
        [pscustomobject]$record
      }
      $target = Join-Path $OutputDirectory ($_.BaseName + '.csv')
      $rows | Export-Csv -LiteralPath $target -NoTypeInformation -Encoding utf8
    }
    finally {
      $workbook.Close($false)
    }
  }
}
finally {
  $excel.Quit()
  [Runtime.InteropServices.Marshal]::ReleaseComObject($excel) | Out-Null
}