// Split only at top level: loops, conditionals, functions and action parameters
// must stay intact. Comments are removed without touching quoted strings.
export function splitGcsimStatements(input: string): string[] {
  const statements: string[] = [];
  const stack: string[] = [];
  // Replacing comments up front also lets a comment appear before an else.
  input = input.replace(/"(?:\\.|[^"\\])*"|'(?:\\.|[^'\\])*'|#[^\n]*|\/\/[^\n]*/g, (match) => match.startsWith("#") || match.startsWith("//") ? " " : match);
  let text = "";
  let quote = "";
  let escaped = false;
  const flush = () => { if (text.trim()) statements.push(text.trim()); text = ""; };
  for (let i = 0; i < input.length; i++) {
    const char = input[i];
    if (quote) {
      text += char;
      if (escaped) escaped = false;
      else if (char === "\\") escaped = true;
      else if (char === quote) quote = "";
      continue;
    }
    if (char === '"' || char === "'") { quote = char; text += char; continue; }
    if ("([{".includes(char)) {
      stack.push(char);
      if (stack.length > 64) throw new Error("Config is nested too deeply.");
    } else if (")]}".includes(char)) {
      const expected: Record<string, string> = { ")": "(", "]": "[", "}": "{" };
      if (stack.pop() !== expected[char]) throw new Error(`Unmatched '${char}' at position ${i + 1}.`);
    }
    text += char;
    if (stack.length === 0 && char === ";") flush();
    // Keep an else branch attached to its if statement.
    if (stack.length === 0 && char === "}" && !/^\s*else\b/.test(input.slice(i + 1))) flush();
  }
  if (quote) throw new Error("Unclosed quoted string.");
  if (stack.length) throw new Error("Unclosed bracket or parenthesis.");
  if (text.trim()) throw new Error("Missing ';' at the end of a statement.");
  return statements;
}