// Set one string variable in a tfvars JSON file, preserving its other keys
// (JSON allows no comments, so the file cannot mark itself as generated:
// deploy-site.sh writes release_sha into infra/terraform.tfvars.json here).
import { existsSync, readFileSync, writeFileSync } from 'node:fs'

const [file, key, value] = process.argv.slice(2)
if (!file || !key || value === undefined) {
  console.error('usage: patch-tfvars.mjs <file.tfvars.json> <key> <value>')
  process.exit(2)
}

const vars = existsSync(file) ? JSON.parse(readFileSync(file, 'utf8')) : {}
vars[key] = value
writeFileSync(file, JSON.stringify(vars, null, 2) + '\n')