// Rôle : fournit les helpers purs de versioning et rollback optimiste des données modules.
function hasOwnValue(data, key) {
  return Object.prototype.hasOwnProperty.call(data, key);
}

function uniqueKeys(keys) {
  return [...new Set((Array.isArray(keys) ? keys : []).map((key) => String(key || "")).filter(Boolean))];
}

export function createModuleDataCheckpoint(moduleData, versionsByKey, key) {
  const version = (versionsByKey[key] || 0) + 1;
  return {
    key,
    version,
    hadValue: hasOwnValue(moduleData, key),
    value: moduleData[key]
  };
}

export function createModuleDataCheckpoints(moduleData, versionsByKey, keys) {
  return uniqueKeys(keys).map((key) => createModuleDataCheckpoint(moduleData, versionsByKey, key));
}

export function commitModuleDataCheckpoints(versionsByKey, checkpoints) {
  const nextVersions = { ...versionsByKey };
  checkpoints.forEach((checkpoint) => {
    nextVersions[checkpoint.key] = checkpoint.version;
  });
  return nextVersions;
}

export function applyModuleDataValue(moduleData, key, value) {
  const nextModuleData = { ...moduleData };
  if (value == null) delete nextModuleData[key];
  else nextModuleData[key] = value;
  return nextModuleData;
}

export function removeModuleDataKeys(moduleData, keys) {
  const nextModuleData = { ...moduleData };
  uniqueKeys(keys).forEach((key) => {
    delete nextModuleData[key];
  });
  return nextModuleData;
}

export function rollbackModuleDataCheckpoints(moduleData, versionsByKey, checkpoints) {
  let nextModuleData = moduleData;
  checkpoints.forEach((checkpoint) => {
    if (versionsByKey[checkpoint.key] !== checkpoint.version) return;
    if (nextModuleData === moduleData) nextModuleData = { ...moduleData };
    if (checkpoint.hadValue) nextModuleData[checkpoint.key] = checkpoint.value;
    else delete nextModuleData[checkpoint.key];
  });
  return nextModuleData;
}