// Name: Merge CSV Files
// Description: Drop multiple CSV files to merge them into a single CSV file
// Author: zacjones93

import "@johnlindquist/kit"

const droppedFiles = await drop("Drop CSV files to merge")

if (!Array.isArray(droppedFiles) || droppedFiles.length === 0) {
  await div(md("No files were dropped"))
  exit()
}

const csvFiles = droppedFiles.filter(file => 
  file.path.toLowerCase().endsWith('.csv')
)

if (csvFiles.length === 0) {
  await div(md("No CSV files found in the dropped files"))
  exit()
}

let mergedData = []
let headers = null

for (const file of csvFiles) {
  const content = await readFile(file.path, 'utf-8')
  const lines = content.trim().split('\n')
  
  if (lines.length === 0) continue
  
  // Use first file's headers as the master headers
  if (headers === null) {
    headers = lines[0]
    mergedData.push(headers)
  }
  
  // Add data rows (skip header row for subsequent files)
  const dataRows = headers === lines[0] ? lines.slice(1) : lines.slice(1)
  mergedData.push(...dataRows)
}

if (mergedData.length <= 1) {
  await div(md("No data found to merge"))
  exit()
}

const mergedCsv = mergedData.join('\n')
const outputPath = home("Downloads", `merged-${Date.now()}.csv`)

await writeFile(outputPath, mergedCsv)
await revealFile(outputPath)

await div(md(`
# CSV Files Merged Successfully!

**Files processed:** ${csvFiles.length}
**Total rows:** ${mergedData.length - 1} (excluding header)
**Output file:** ${outputPath}

The merged CSV file has been saved to your Downloads folder.
`))