import type { TaskLogEntry } from "@fusion/core";

export interface TimingEvent {
  timestamp: string;
  durationMs?: number;
  summary: string;
}

function summarizeTimingLabel(entry: TaskLogEntry): string {
  const timingText = entry.action || entry.outcome || "";
  const stripped = timingText
    .replace(/^\[timing\]\s*/i, "")
    .replace(/^\[[^\]]+\]\s*/i, "")
    .replace(/\s+in\s+\d+(?:\.\d+)?ms\b/i, "")
    .replace(/\s+after\s+\d+(?:\.\d+)?ms\b/i, "")
    .trim();
  return stripped || "Timing event";
}

export function extractTimingEvents(logEntries: TaskLogEntry[]): TimingEvent[] {
  return logEntries
    .filter((entry) => {
      const actionText = typeof entry.action === "string" ? entry.action : "";
      const outcomeText = typeof entry.outcome === "string" ? entry.outcome : "";
      return actionText.includes("[timing]") || outcomeText.includes("[timing]");
    })
    .map((entry) => {
      const haystack = `${entry.action ?? ""}\n${entry.outcome ?? ""}`;
      const durationMatch = haystack.match(/(\d+(?:\.\d+)?)ms\b/i);
      const durationMs = durationMatch ? Number(durationMatch[1]) : undefined;
      return {
        timestamp: entry.timestamp,
        durationMs: Number.isFinite(durationMs) ? durationMs : undefined,
        summary: summarizeTimingLabel(entry),
      };
    });
}

export function getTimedDurationMs(logEntries: TaskLogEntry[] | undefined): number | null {
  if (!logEntries || logEntries.length === 0) return null;
  let total = 0;
  let counted = 0;
  for (const event of extractTimingEvents(logEntries)) {
    if (typeof event.durationMs !== "number") continue;
    total += event.durationMs;
    counted += 1;
  }
  return counted > 0 ? total : null;
}