const fs = require('fs');
const yaml = require('js-yaml');

module.exports = function extractDockerImages(fileContent) {
  const result = [];

  try {
    const doc = yaml.load(fileContent, { schema: yaml.DEFAULT_SCHEMA });

    if (!doc.services) return [];

    for (const [serviceName, serviceDef] of Object.entries(doc.services)) {
      let image = serviceDef.image;

      // Resolve anchors/merges if image is not directly present
      if (!image && serviceDef['<<']) {
        const merge = serviceDef['<<'];
        if (Array.isArray(merge)) {
          merge.forEach(m => {
            if (m.image) image = m.image;
          });
        } else if (merge.image) {
          image = merge.image;
        }
      }

      if (image) {
        const [depName, currentValue] = image.split(':');
        result.push({
          depName: depName,
          currentValue: currentValue || 'latest',
          service: serviceName // <- added for Renovate PR title
        });
      }
    }
  } catch (err) {
    console.error('Failed parsing docker-compose.yml:', err);
  }

  return result;
};