splitenv.mjs

import fs from "fs";
import path from "path";

// Usage: node splitenv.js <input-file> <prefix1> [prefix2] [...]
const args = process.argv.slice(2);
if (args.length < 2) {
  console.error(
    `Usage: node ${path.basename(process.argv[1])} <input-file> <prefix...>`,
  );
  process.exit(1);
}

const [inputFile, ...prefixes] = args;
const baseDir = path.dirname(inputFile);

// Map each prefix to its suffix (stripping trailing underscores)
const prefixToSuffix = prefixes.reduce((acc, prefix) => {
  acc[prefix] = prefix.replace(/_+$/, "");
  return acc;
}, {});

// Prepare containers for each output group
const groupEntries = Object.values(prefixToSuffix).reduce((acc, suffix) => {
  acc[suffix] = [];
  return acc;
}, {});

// Read the input .env file
let content;
try {
  content = fs.readFileSync(inputFile, "utf-8");
} catch (err) {
  console.error(`Error reading file '${inputFile}':`, err.message);
  process.exit(1);
}

// Split into lines
const rawLines = content.split(/\r?\n/);

// Merge multi-line values (quoted values spanning lines)
const mergedLines = [];
let inMultiline = false;
let multilineBuffer = "";
let currentQuote = null;

rawLines.forEach((line) => {
  if (!inMultiline) {
    const match = line.match(/^([A-Za-z_][A-Za-z0-9_]*)=(.*)$/);
    if (match) {
      const rest = match[2];
      const trimmed = rest.trim();
      const startsWithQuote =
        trimmed.startsWith(`"`) || trimmed.startsWith(`'`);
      const quoteChar = trimmed.charAt(0);
      const endsWithQuote = trimmed.endsWith(quoteChar) && trimmed.length > 1;
      if (startsWithQuote && !endsWithQuote) {
        inMultiline = true;
        currentQuote = quoteChar;
        multilineBuffer = line;
      } else {
        mergedLines.push(line);
      }
    } else {
      // Copy non key=value lines (comments/blanks will be filtered later)
      mergedLines.push(line);
    }
  } else {
    multilineBuffer += "\n" + line;
    if (line.trim().endsWith(currentQuote)) {
      inMultiline = false;
      mergedLines.push(multilineBuffer);
      multilineBuffer = "";
      currentQuote = null;
    }
  }
});
if (inMultiline) {
  // Unterminated multiline: push anyway
  mergedLines.push(multilineBuffer);
}

// Process each logical line
mergedLines.forEach((line) => {
  const trimmed = line.trim();
  // Skip blank lines and comments
  if (!trimmed || trimmed.startsWith("#")) return;

  const idx = line.indexOf("=");
  if (idx === -1) return;

  const key = line.slice(0, idx);
  const value = line.slice(idx + 1);

  // Check if the key matches any prefix
  let matched = false;
  for (const prefix of prefixes) {
    if (key.startsWith(prefix)) {
      const suffix = prefixToSuffix[prefix];
      const newKey = key.slice(prefix.length);
      groupEntries[suffix].push({ key: newKey, value });
      matched = true;
      break;
    }
  }
  if (!matched) {
    // Common variable: copy to all groups
    Object.values(prefixToSuffix).forEach((suffix) => {
      groupEntries[suffix].push({ key, value });
    });
  }
});

// Write out each .env in its corresponding folder
Object.entries(groupEntries).forEach(([suffix, entries]) => {
  const dirName = suffix.toLowerCase();
  const dirPath = path.join(baseDir, dirName);

  // Ensure directory exists
  if (!fs.existsSync(dirPath) || !fs.statSync(dirPath).isDirectory()) {
    console.error(
      `Error: Directory '${dirPath}' for prefix '${suffix}' does not exist.`,
    );
    process.exit(1);
  }

  const outPath = path.join(dirPath, ".env");
  const linesOut = entries.map(({ key, value }) => `${key}=${value}`);
  const contentOut =
    [
      "# file generated by file:///./../splitenv.mjs from the file:///./../.env file\n",
      ...linesOut,
    ].join("\n") + "\n";

  try {
    fs.writeFileSync(outPath, contentOut, "utf-8");
    console.log(`Wrote ${outPath}`);
  } catch (err) {
    console.error(`Error writing file '${outPath}': ${err.message}`);
    process.exit(1);
  }
});