// services/cdrFeedParser.js
// Parse cdr_feed JSON payloads (field names vary by Webex release).

function normKey(key) {
  return String(key).toLowerCase().replace(/[^a-z0-9]/g, '');
}

function indexCdrRecord(item) {
  if (!item || typeof item !== 'object') return {};
  const idx = {};
  for (const [k, v] of Object.entries(item)) {
    idx[normKey(k)] = v;
  }
  return idx;
}

/** Read a CDR field by any known alias (camelCase or report column label). */
export function cdrField(item, ...aliases) {
  if (!item) return null;
  const idx = indexCdrRecord(item);
  for (const alias of aliases) {
    const v = idx[normKey(alias)];
    if (v != null && v !== '') return v;
  }
  return null;
}

export function cdrRecordId(item) {
  return cdrField(
    item,
    'reportId', 'Report ID', 'reportID',
    'callRecordingId',
  );
}

export function cdrStartTime(item) {
  return cdrField(
    item,
    'startTime', 'start', 'callStartTime',
    'Start time', 'Start Time',
    'answerTime', 'Answer time', 'Answer Time',
  );
}

export function cdrDurationSeconds(item) {
  const raw = cdrField(
    item,
    'durationSeconds', 'duration', 'callDuration', 'talkDuration', 'length',
    'Duration',
  );
  return Number(raw || 0);
}

export function cdrDirectionValue(item) {
  return String(cdrField(
    item,
    'direction', 'callDirection', 'callType', 'directionIndicator',
    'Direction', 'Call direction', 'Call Direction',
  ) || '').toUpperCase();
}

export function cdrDispositionValue(item) {
  return String(cdrField(
    item,
    'status', 'result', 'callResult', 'callOutcome', 'callStatus',
    'Disposition', 'Answer indicator', 'Call outcome',
  ) || 'unknown');
}

export function cdrCallingNumber(item) {
  return cdrField(
    item,
    'callingNumber', 'callingParty', 'callingName',
    'Calling number', 'Calling Number',
    'User number', 'User Number',
  );
}

export function cdrCalledNumber(item) {
  return cdrField(
    item,
    'calledNumber', 'calledParty', 'calledName',
    'Called number', 'Called Number',
  );
}

export function cdrCallingLineId(item) {
  return cdrField(item, 'callingLineId', 'Calling line ID', 'calling line id');
}

export function cdrCalledLineId(item) {
  return cdrField(item, 'calledLineId', 'Called line ID', 'called line id');
}

export function cdrDialedDigits(item) {
  return cdrField(item, 'dialedDigits', 'Dialed digits', 'dialed digits');
}

export function cdrCallOutcome(item) {
  return cdrField(item, 'Call outcome', 'call outcome');
}

export function cdrCallOutcomeReason(item) {
  return cdrField(item, 'Call outcome reason', 'call outcome reason');
}

export function cdrCallerIdNumber(item) {
  return cdrField(item, 'Caller ID number', 'caller id number', 'callerIdNumber');
}

export function cdrUserName(item) {
  return cdrField(item, 'User', 'user');
}

export function cdrUserNumber(item) {
  return cdrField(item, 'User number', 'user number');
}

export function cdrModel(item) {
  return cdrField(item, 'Model', 'model');
}

export function cdrSiteMainNumber(item) {
  return cdrField(item, 'Site main number', 'site main number');
}

export function formatCallDisposition(outcome, reason) {
  const o = String(outcome || '').trim();
  const r = String(reason || '').trim();
  if (!o) return 'unknown';
  if (!r || r.toLowerCase() === 'normal') return o;
  return `${o} / ${r}`;
}

export function cdrDedupKey(item) {
  const id = cdrRecordId(item);
  if (id) return `id:${id}`;
  return [
    cdrStartTime(item) || '',
    cdrCallingNumber(item) || '',
    cdrCalledNumber(item) || '',
    cdrDurationSeconds(item) || '',
  ].join('|');
}

export function extractCdrFeedList(data) {
  if (!data) return [];
  if (Array.isArray(data)) return data;
  if (Array.isArray(data.items)) return data.items;
  if (data.items && typeof data.items === 'object' && data.items !== null) {
    const keys = Object.keys(data.items).filter((k) => /^\d+$/.test(k)).sort((a, b) => parseInt(a, 10) - parseInt(b, 10));
    if (keys.length > 0) return keys.map((k) => data.items[k]);
  }
  const topKeys = Object.keys(data).filter((k) => /^\d+$/.test(k)).sort((a, b) => parseInt(a, 10) - parseInt(b, 10));
  if (topKeys.length > 0) return topKeys.map((k) => data[k]);
  for (const key of ['records', 'cdrRecords', 'callHistory', 'calls']) {
    if (Array.isArray(data[key])) return data[key];
  }
  if (data.data) {
    if (Array.isArray(data.data)) return data.data;
    if (Array.isArray(data.data.items)) return data.data.items;
  }
  for (const v of Object.values(data)) {
    if (Array.isArray(v)) return v;
  }
  return [];
}

export function describeCdrFeedPayload(data) {
  if (!data) return 'empty body';
  if (Array.isArray(data)) return `array[${data.length}]`;
  const keys = Object.keys(data);
  const parts = [`keys=${keys.slice(0, 12).join(',')}`];
  for (const k of ['items', 'records', 'cdrRecords', 'next', 'data']) {
    const v = data[k];
    if (Array.isArray(v)) parts.push(`${k}.length=${v.length}`);
    else if (v && typeof v === 'object') parts.push(`${k}.keys=${Object.keys(v).slice(0, 6).join(',')}`);
  }
  return parts.join(' ');
}

/**
 * Parse Webex RFC5988 Link header and return the `rel="next"` URL.
 * @param {string|undefined} linkHeader
 * @returns {string|null}
 */
export function parseCdrFeedLinkNext(linkHeader) {
  if (!linkHeader || typeof linkHeader !== 'string') return null;
  for (const part of linkHeader.split(',')) {
    const m = part.match(/<([^>]+)>\s*;\s*rel\s*=\s*"?next"?/i);
    if (m) return m[1];
  }
  return null;
}

/**
 * Resolve the next cdr_feed page from response body and/or Link header.
 * @returns {{ url: string, params: object|null }|null}
 */
export function resolveCdrFeedNextPage(data, headers, baseUrl, baseParams) {
  const linkNext = parseCdrFeedLinkNext(headers?.link || headers?.Link);
  if (linkNext) return { url: linkNext, params: null };

  const token = data?.next || data?.['next'] || data?.metadata?.next || null;
  if (!token) return null;
  if (typeof token === 'string' && token.startsWith('http')) {
    return { url: token, params: null };
  }
  return { url: baseUrl, params: { ...baseParams, next: token } };
}