"use strict";

(function (global) {
  const nowMs = () => (global.performance?.now ? global.performance.now() : Date.now());
  const buckets = new Map();
  let frameOpen = null;
  let frameCount = 0;
  let lastQualityCheckAt = 0;
  let tier = "high";
  let dprScale = 1;
  let resizeRequested = false;

  function bucketFor(label) {
    let b = buckets.get(label);
    if (!b) {
      b = { label, ms: 0, avg: 0, max: 0, calls: 0, last: 0 };
      buckets.set(label, b);
    }
    return b;
  }

  function begin(label) {
    const start = nowMs();
    return () => {
      const elapsed = Math.max(0, nowMs() - start);
      const b = bucketFor(label);
      b.ms += elapsed;
      b.calls += 1;
      b.last = elapsed;
      if (elapsed > b.max) b.max = elapsed;
      return elapsed;
    };
  }

  function beginFrame() {
    frameOpen = nowMs();
    return frameOpen;
  }

  function smoothBuckets() {
    for (const b of buckets.values()) {
      b.avg = b.avg ? b.avg * 0.82 + b.ms * 0.18 : b.ms;
      b.ms = 0;
      b.calls = 0;
    }
  }

  function qualityFromFps(fps) {
    const f = Number(fps) || 0;
    if (f > 55) return { tier: "high", dpr: 1 };
    if (f < 32) return { tier: "low", dpr: 0.72 };
    if (f < 45) return { tier: "mid", dpr: 0.86 };
    return { tier: tier === "low" ? "mid" : tier, dpr: tier === "low" ? 0.86 : dprScale };
  }

  function endFrame(rawDt = 0, fps = global.__tarinaiFps || 0) {
    frameCount += 1;
    if (frameOpen != null) {
      const b = bucketFor("frame.total");
      const elapsed = Math.max(0, nowMs() - frameOpen);
      b.ms += elapsed;
      b.calls += 1;
      b.last = elapsed;
      if (elapsed > b.max) b.max = elapsed;
      frameOpen = null;
    }
    const t = nowMs();
    if (t - lastQualityCheckAt >= 750) {
      lastQualityCheckAt = t;
      smoothBuckets();
      const next = qualityFromFps(fps);
      const nextDpr = next.dpr;
      if (next.tier !== tier || Math.abs(nextDpr - dprScale) > 0.04) {
        tier = next.tier;
        dprScale = nextDpr;
        resizeRequested = true;
      }
    }
  }

  function renderQualityTier() {
    return tier;
  }

  function dprScaleValue() {
    return dprScale;
  }

  function consumeResizeRequest() {
    const v = resizeRequested;
    resizeRequested = false;
    return v;
  }

  function snapshot() {
    const entries = [...buckets.values()].map(b => ({
      label: b.label,
      avg: Number((b.avg || 0).toFixed(2)),
      max: Number((b.max || 0).toFixed(2)),
      last: Number((b.last || 0).toFixed(2)),
      calls: b.calls || 0,
    })).sort((a, b) => b.avg - a.avg);
    return { tier, dprScale, frameCount, entries };
  }

  global.TarinaiPerf = Object.freeze({
    begin,
    beginFrame,
    endFrame,
    renderQualityTier,
    dprScale: dprScaleValue,
    consumeResizeRequest,
    snapshot,
  });
})(typeof window !== "undefined" ? window : globalThis);