import { NextRequest, NextResponse } from "next/server";
import fs from "node:fs/promises";
import { assertLocalRequest } from "@/lib/api/localOnly";
import { getJob, estimateRealtimeMultiplier } from "@/lib/whisperjav/db";

export const runtime = "nodejs";
export const dynamic = "force-dynamic";

const LOG_TAIL_LINES = 50;

export async function GET(req: NextRequest, ctx: { params: Promise<{ id: string }> }) {
  const blocked = assertLocalRequest(req);
  if (blocked) return blocked;

  const { id } = await ctx.params;
  const job = getJob(id);
  if (!job) return NextResponse.json({ error: "Not found" }, { status: 404 });

  let logTail: string[] = [];
  try {
    const raw = await fs.readFile(job.logPath, "utf8");
    const lines = raw.split(/\r?\n/);
    logTail = lines.slice(-LOG_TAIL_LINES - 1).filter(Boolean);
  } catch { /* log may not exist yet */ }

  // ETA: per-mode multiplier from history × video duration − elapsed.
  // Returns null when we can't compute (no duration / not running yet).
  let etaSec: number | null = null;
  if (
    (job.status === "queued" || job.status === "running") &&
    job.videoDurationSec && job.videoDurationSec > 0 &&
    job.mode
  ) {
    const multiplier = estimateRealtimeMultiplier(job.mode);
    const totalProjected = job.videoDurationSec * multiplier;
    const start = job.startedAt ?? job.enqueuedAt;
    const elapsedSec = (Date.now() - start) / 1000;
    etaSec = Math.max(0, totalProjected - elapsedSec);
  }

  return NextResponse.json({ ...job, logTail, etaSec });
}