import fs from 'node:fs/promises';
import path from 'node:path';

const root = path.resolve(import.meta.dirname, '..');
const schemaPath = path.join(root, 'database/schema.sql');
const columnSql = '  activated_at DATETIME NULL';

function hasActivatedAt(schema) {
  return /\bactivated_at\s+DATETIME\s+NULL\b/i.test(schema);
}

function splitRouteTableBody(body) {
  const lines = body.split('\n');
  const trailing = [];
  while (lines.length > 0 && lines[lines.length - 1].trim() === '') {
    trailing.unshift(lines.pop());
  }
  return { lines, trailing };
}

function isTableConstraint(line) {
  return /^\s*,?\s*(?:PRIMARY\s+KEY|CONSTRAINT|FOREIGN\s+KEY|UNIQUE\s*\()/i.test(line);
}

function hasLeadingComma(line) {
  return /^\s*,/.test(line);
}

function ensureCommaBeforeInsert(lines, targetIndex) {
  const previousIndex = targetIndex - 1;
  if (previousIndex < 0) return;
  const previous = lines[previousIndex].trimEnd();
  if (!previous.endsWith(',')) lines[previousIndex] = `${previous},`;
}

function columnForTarget(lines, insertBefore) {
  if (insertBefore === -1) return columnSql;
  return hasLeadingComma(lines[insertBefore]) ? columnSql : `${columnSql},`;
}

function insertActivatedAt(schema) {
  if (hasActivatedAt(schema)) return schema;

  const routeTable = /CREATE\s+TABLE\s+(?:IF\s+NOT\s+EXISTS\s+)?routes\s*\((?<body>[\s\S]*?)\);/i.exec(schema);
  if (!routeTable?.groups?.body) {
    throw new Error('Die routes-Tabelle wurde in database/schema.sql nicht gefunden.');
  }

  const tableSql = routeTable[0];
  const body = routeTable.groups.body;
  const { lines, trailing } = splitRouteTableBody(body);
  const insertBefore = lines.findIndex(isTableConstraint);
  const targetIndex = insertBefore === -1 ? lines.length : insertBefore;

  ensureCommaBeforeInsert(lines, targetIndex);
  lines.splice(targetIndex, 0, columnForTarget(lines, insertBefore));

  return schema.replace(tableSql, tableSql.replace(body, [...lines, ...trailing].join('\n')));
}

const schema = await fs.readFile(schemaPath, 'utf8');
const next = insertActivatedAt(schema);
if (next === schema) {
  console.log('database/schema.sql enthält activated_at bereits.');
} else {
  await fs.writeFile(schemaPath, next);
  console.log('database/schema.sql wurde um routes.activated_at ergänzt.');
}