Function parseLogFile

src/stats.ts:47–72

* Parse a JSONL log file into usage entries. * Handles both old format (without tier/baselineCost) and new format.

(filePath: string)

 * Handles both old format (without tier/baselineCost) and new format.
 */
async function parseLogFile(filePath: string): Promise<UsageEntry[]> {
  try {
    const content = await readTextFile(filePath);
    const lines = content.trim().split("\n").filter(Boolean);
    const entries: UsageEntry[] = [];
    for (const line of lines) {
      try {
        const entry = JSON.parse(line) as Partial<UsageEntry>;
        entries.push({
          timestamp: entry.timestamp || new Date().toISOString(),
          model: entry.model || "unknown",
          tier: entry.tier || "UNKNOWN",
          cost: entry.cost || 0,
          baselineCost: entry.baselineCost || entry.cost || 0,
          savings: entry.savings || 0,
          latencyMs: entry.latencyMs || 0,
        });
      } catch {
        // Skip malformed lines, keep valid ones
      }
    }
    return entries;
  } catch {
    return [];
  }
}

/**
 * Get list of available log files sorted by date (newest first).