// PAREIDOLIA — capture.js
// The offering: camera (or file) → downscaled JPEG → the awaken rite.
//
// Constraints honoured here (ARCHITECTURE.md §2):
//   · client downscale to ≤1024px JPEG, target ≤350KB base64 — cuts upload
//     time AND the VLM prefill bill before a single GPU second is spent.
//   · the awaken call goes through @gradio/client so the VISITOR's own
//     browser-authenticated request pays the ZeroGPU quota, not the Space.
//   · every failure surfaces as poetic copy, never a stack trace.

const MAX_DIM = 1024;
const TARGET_B64_BYTES = 350 * 1024;
const QUALITY_LADDER = [0.85, 0.75, 0.65, 0.55, 0.45];

/** True when the page runs in static dev mode (no backend behind it). */
export function isMockMode() {
  return new URLSearchParams(location.search).has("mockwall");
}

/** True when the capture screen should skip getUserMedia (screenshots, dev). */
export function isMockCam() {
  return new URLSearchParams(location.search).has("mockcam");
}

// ---------------------------------------------------------------- downscale

/**
 * Draw any image source onto a canvas at ≤MAX_DIM and walk a JPEG quality
 * ladder until the base64 payload fits the target. Returns both the dataUrl
 * (for instant local display) and the bare b64 (for the wire).
 */
async function downscale(source, srcW, srcH) {
  const scale = Math.min(1, MAX_DIM / Math.max(srcW, srcH));
  const w = Math.max(1, Math.round(srcW * scale));
  const h = Math.max(1, Math.round(srcH * scale));
  const canvas = document.createElement("canvas");
  canvas.width = w;
  canvas.height = h;
  const ctx = canvas.getContext("2d");
  ctx.drawImage(source, 0, 0, w, h);

  let dataUrl = "";
  for (const q of QUALITY_LADDER) {
    dataUrl = canvas.toDataURL("image/jpeg", q);
    if (dataUrl.length - "data:image/jpeg;base64,".length <= TARGET_B64_BYTES) break;
  }
  return { dataUrl, b64: dataUrl.split(",")[1], width: w, height: h };
}

/** Downscale a File/Blob picked from the gallery. */
export async function fileToJpeg(file) {
  const url = URL.createObjectURL(file);
  try {
    const img = await new Promise((res, rej) => {
      const el = new Image();
      el.onload = () => res(el);
      el.onerror = () => rej(new Error("undecodable image"));
      el.src = url;
    });
    return await downscale(img, img.naturalWidth, img.naturalHeight);
  } finally {
    URL.revokeObjectURL(url);
  }
}

/** Freeze the current video frame into a downscaled JPEG. */
export async function frameToJpeg(videoEl) {
  return downscale(videoEl, videoEl.videoWidth || 1280, videoEl.videoHeight || 720);
}

// ---------------------------------------------------------------- camera UI

/**
 * Build the capture surface inside `stageEl`: a live environment-facing
 * camera with a shutter, falling back gracefully to a candlelit file-pick
 * altar when no camera will speak to us (denied, absent, or ?mockcam=1).
 *
 * onPhoto receives {dataUrl, b64, width, height}. Returns {destroy()}.
 */
export function createCaptureSession(stageEl, { onPhoto }) {
  let stream = null;
  let alive = true;
  stageEl.innerHTML = "";

  const fileInput = document.createElement("input");
  fileInput.type = "file";
  fileInput.accept = "image/*";
  fileInput.setAttribute("capture", "environment");
  fileInput.style.display = "none";
  fileInput.addEventListener("change", async () => {
    const f = fileInput.files && fileInput.files[0];
    if (!f) return;
    try {
      onPhoto(await fileToJpeg(f));
    } catch {
      hintEl.textContent = "that image kept its secrets — try another";
    }
  });
  stageEl.appendChild(fileInput);

  const hintEl = document.createElement("p");
  hintEl.className = "capture__hint";
  hintEl.textContent = "point it at anything. a hydrant. a mug. the chair that watches you sleep.";

  function buildFallback(message) {
    stageEl.querySelectorAll(".capture__controls, video, .capture__hint, .capture__fallback")
      .forEach((n) => n.remove());
    const alt = document.createElement("div");
    alt.className = "capture__fallback";
    alt.innerHTML = `
      <div class="empty__eyes" aria-hidden="true">· ·</div>
      <h2>${message}</h2>
      <button class="cta" type="button">offer a photograph</button>
      <p>jpeg · png · whatever holds a soul</p>`;
    alt.querySelector("button").addEventListener("click", () => fileInput.click());
    // deskbound visitors get the phone escape hatch in the panel footer
    if (window.qrcode) {
      try {
        const qr = window.qrcode(0, "M");
        qr.addData(location.origin + location.pathname);
        qr.make();
        const foot = document.createElement("div");
        foot.className = "capture__qrfoot";
        foot.innerHTML = qr.createSvgTag({ cellSize: 3, margin: 0, scalable: true });
        foot.querySelectorAll("rect, path").forEach((n) => {
          if ((n.getAttribute("fill") || "").toLowerCase() !== "white") n.setAttribute("fill", "#efe6d4");
          else n.setAttribute("fill", "transparent");
        });
        const label = document.createElement("p");
        label.textContent = "or point your phone at this";
        foot.appendChild(label);
        alt.appendChild(foot);
      } catch { /* a panel without a QR is still a panel */ }
    }
    stageEl.appendChild(alt);
  }

  async function buildCamera() {
    const video = document.createElement("video");
    video.autoplay = true;
    video.muted = true;
    video.playsInline = true;
    try {
      stream = await navigator.mediaDevices.getUserMedia({
        video: { facingMode: "environment", width: { ideal: 1920 } },
        audio: false,
      });
    } catch {
      buildFallback("the camera kept its eyes closed — offer a photograph instead");
      return;
    }
    if (!alive) { stream.getTracks().forEach((t) => t.stop()); return; }
    video.srcObject = stream;
    stageEl.appendChild(video);
    stageEl.appendChild(hintEl);

    const controls = document.createElement("div");
    controls.className = "capture__controls";
    const galleryBtn = document.createElement("button");
    galleryBtn.className = "ghostbtn";
    galleryBtn.textContent = "from gallery";
    galleryBtn.addEventListener("click", () => fileInput.click());
    const shutter = document.createElement("button");
    shutter.className = "shutter";
    shutter.setAttribute("aria-label", "take the photograph");
    shutter.addEventListener("click", async () => {
      try {
        onPhoto(await frameToJpeg(video));
      } catch {
        hintEl.textContent = "the frame slipped away — try once more";
      }
    });
    controls.append(galleryBtn, shutter);
    stageEl.appendChild(controls);
  }

  if (isMockCam() || !navigator.mediaDevices?.getUserMedia) {
    buildFallback("the spirits will read any photograph you offer");
  } else {
    buildCamera();
  }

  return {
    destroy() {
      alive = false;
      if (stream) stream.getTracks().forEach((t) => t.stop());
      stream = null;
      stageEl.innerHTML = "";
    },
  };
}

// ---------------------------------------------------------------- the rite

export const QUOTA_MESSAGE =
  "the spirits are overwhelmed just now — the same photo waits; try again in a breath";
export const QUOTA_MESSAGE_CROWDED =
  "the spirits are truly crowded — try in a few minutes, or sign in for your own quota";
export const VEIL_MESSAGE =
  "the veil would not part this time — breathe, and offer it again";

/** The signed-in-for-your-own-quota door (ARCHITECTURE §0: each visitor spends
 *  their OWN ZeroGPU quota — anonymous per-IP is shared and quickly spent). */
export const HF_LOGIN_URL = "https://huggingface.co/login";

// ZeroGPU quota exhaustion surfaces as a gr.Error whose message mentions the
// GPU quota — e.g. "You have exceeded your GPU quota (75s requested vs. 12s
// left). Sign in to continue…" — relayed by @gradio/client as a thrown Error
// (or, in some paths, a status-shaped object). Case-insensitive on purpose;
// 429/unauthorized cover the proxy-level flavors of the same wall.
const QUOTA_RE = /quota|exceed|429|zero ?gpu|sign.?in|login|unauthor/i;

/** Pull human text out of whatever @gradio/client rejected with: an Error,
 *  a bare string, or a status-shaped object ({message} / {detail} / {title}). */
export function errorText(err) {
  if (err == null) return "";
  if (typeof err === "string") return err;
  for (const key of ["message", "detail", "title"]) {
    if (typeof err[key] === "string" && err[key]) return err[key];
  }
  try {
    // custom toString()s (and Error subclasses) speak for themselves; an
    // anonymous object stays silent — raw JSON is not for visitors' eyes
    // (console.warn in awaken() already logged the full object).
    const s = String(err);
    return s === "[object Object]" ? "" : s;
  } catch {
    return "";
  }
}

/**
 * Map any awaken failure onto the poetic line the visitor should see.
 * Quota walls become QUOTA_MESSAGE (main.js pairs it with a visible
 * hf.co/login link); anything stack-trace-shaped becomes VEIL_MESSAGE.
 * Exported pure so the matcher is provable in a plain node check.
 */
export function poeticAwakenError(err) {
  const raw = errorText(err);
  if (QUOTA_RE.test(raw)) return new Error(QUOTA_MESSAGE);
  return new Error(
    raw.length > 0 && raw.length < 90 && !/error|exception|trace/i.test(raw)
      ? raw
      : VEIL_MESSAGE,
  );
}

/**
 * Is this awaken result a TRANSIENT busy wall (ZeroGPU per-IP quota / 429),
 * not a soul-declined refusal and not a hard break? The server now answers
 * with an explicit {quota:true} flag; we also catch a refusal whose reason
 * reads like a quota wall (belt-and-braces if the flag is ever absent).
 * Pure + exported so the classifier is provable in a plain node check.
 */
export function isBusyResult(out) {
  if (!out || typeof out !== "object") return false;
  if (out.quota === true) return true;
  if (out.refused && QUOTA_RE.test(String(out.reason || ""))) return true;
  return false;
}

/** Normalize any busy signal (structured response OR thrown quota error) into
 *  one retryable outcome shape the shell can branch on without re-sniffing. */
function busyOutcome(reason) {
  const clean = String(reason || "").trim();
  return {
    refused: true,
    busy: true,
    quota: true,
    retry: true,
    reason: clean && clean.length < 200 ? clean : QUOTA_MESSAGE,
  };
}

let gradioClient = null;
// the last offering, retained so a BUSY 'try again' re-submits the SAME photo
// without re-opening the camera (the visitor never re-takes the shot).
let lastImageB64 = null;

/**
 * Invoke the awaken endpoint. The browser-side @gradio/client call is what
 * routes GPU spend to the visitor's own ZeroGPU quota (ARCHITECTURE §0) —
 * never proxy this through a plain fetch.
 *
 * Resolves one of:
 *   · {refused:false, record, record_token}   — the awakening
 *   · {refused:true, reason}                   — a soul declined (poetic)
 *   · {refused:true, busy:true, quota:true, retry:true, reason}
 *                                              — transient ZeroGPU 429/quota
 * A busy/quota wall (structured response OR a thrown quota error) NEVER
 * rejects — it resolves as a busy outcome so the shell shows an honest,
 * retryable state instead of the generic veil. Only a genuine break rejects,
 * with an Error whose .message is already poetic.
 */
export async function awaken(imageB64) {
  lastImageB64 = imageB64;
  if (isMockMode()) return mockAwaken(imageB64);

  try {
    let out;
    if (typeof window !== "undefined" && typeof window.__awakenStub === "function") {
      // test seam (busy/429 path the mock backend can't produce): the stub
      // returns a RAW server-shaped payload, so every real downstream step —
      // isBusyResult classification, busyOutcome normalize, lastImageB64
      // retention for retry — still runs exactly as in production.
      out = await window.__awakenStub(imageB64);
    } else {
      if (!gradioClient) {
        const { Client } = await import("https://cdn.jsdelivr.net/npm/@gradio/client/+esm");
        gradioClient = await Client.connect(window.location.origin);
      }
      const r = await gradioClient.predict("/awaken", { image_b64: imageB64 });
      out = Array.isArray(r?.data) ? r.data[0] : r?.data;
    }
    if (!out || typeof out !== "object") throw new Error(VEIL_MESSAGE);
    if (isBusyResult(out)) return busyOutcome(out.reason);
    return out;
  } catch (err) {
    console.warn("awaken failed:", err);
    // a thrown quota wall is the SAME transient busy state — route it there
    // (honest + retryable) rather than down the generic veil path.
    if (QUOTA_RE.test(errorText(err))) return busyOutcome(QUOTA_MESSAGE);
    throw poeticAwakenError(err);
  }
}

/**
 * Re-run the awaken rite with the RETAINED photo (no camera re-open). Used by
 * the BUSY 'try again' affordance. Resolves the same shapes as awaken().
 * @throws {Error} if there is no retained offering to re-submit.
 */
export async function retryAwaken() {
  if (lastImageB64 == null) throw new Error(VEIL_MESSAGE);
  return awaken(lastImageB64);
}

/**
 * Dev-only stand-in with honest latency so the séance theater is rehearsable
 * from a static file server. The lines are self-aware about being mock — the
 * REAL writing lives behind mind/prompts.py and in web/mock/records.json.
 */
async function mockAwaken(imageB64) {
  const beat = (ms) => new Promise((r) => setTimeout(r, ms));
  await beat(4200 + Math.random() * 2600);
  const souls = [
    {
      object: "rehearsal prop", condition: "imaginary",
      persona: { archetype: "the_understudy", voice: "deadpan_flat", mood: "professional" },
      lines: {
        grudge: "Summoned by a mock backend. No GPU, no voice, no dignity. I will still hit my mark.",
        mutter: "The understudy is always ready.",
      },
    },
    {
      object: "stand-in spirit", condition: "borrowed",
      persona: { archetype: "the_new_hire", voice: "eager_bright", mood: "keen" },
      lines: {
        grudge: "Day one of the dress rehearsal and they hand me placeholder eyes. Noted. Filed. Forgiven, mostly.",
        mutter: "Real eyes arrive with the real backend.",
      },
    },
  ];
  const soul = souls[Math.floor(Math.random() * souls.length)];
  return {
    refused: false,
    record_token: "mock-" + Math.random().toString(36).slice(2, 10),
    record: {
      id: "mock-" + Date.now(),
      ...soul,
      material: "developer optimism",
      setting: "a static file server",
      features: [
        { name: "left placeholder", role: "eye_left", cx: 0.4, cy: 0.38, size: 0.07 },
        { name: "right placeholder", role: "eye_right", cx: 0.6, cy: 0.38, size: 0.07 },
        { name: "stand-in mouth", role: "mouth", cx: 0.5, cy: 0.62, size: 0.1 },
      ],
      image_url: "data:image/jpeg;base64," + imageB64,
      audio_url: null,
      grudge_audio_b64: null,
      created_at: new Date().toISOString(),
    },
  };
}