/* ============================================================
   PixelLock custom frontend
   - drop/upload a PNG
   - theme chips -> prompt
   - retheme / upscale toggle
   - POST /api/edit  { image(base64), theme, prompt, mode }
   - GET  /api/examples  -> before/after gallery
   ============================================================ */
"use strict";

/* Theme presets. `key` mirrors the THEMES dict keys in app/app.py
   (emoji-prefixed) so the backend's THEMES.get(theme_key) resolves the
   instruction even if the prompt field is blank. `swatch` is purely visual. */
const THEMES = [
  { key: "🌋  Molten lava",      label: "Lava",   swatch: "#ff5a1f",
    prompt: "a molten lava theme — glowing magma core, charred black edges, white-hot highlights, bold orange-red ramp" },
  { key: "❄️  Frozen ice",       label: "Ice",    swatch: "#8fe6ff",
    prompt: "a frozen ice theme — pale cyan, frosted surface, white frost highlights, cool blue shadows" },
  { key: "🪙  Solid gold",       label: "Gold",   swatch: "#ffcf45",
    prompt: "a solid gold royal theme — shimmering gold ramp, warm highlights, deep amber shadows" },
  { key: "☢️  Toxic",            label: "Toxic",  swatch: "#7dff3a",
    prompt: "a toxic radioactive theme — sickly neon green, glowing hazard spots, dark slime shadows" },
  { key: "🍂  Autumn dusk",      label: "Autumn", swatch: "#e0673a",
    prompt: "an autumn dusk theme — warm amber and crimson with deep purple shadows" },
  { key: "🌌  Cosmic galaxy",    label: "Cosmic", swatch: "#a06bff",
    prompt: "a cosmic galaxy theme — deep space-purple with tiny star speckles and glowing cyan accents" },
  { key: "🖤  Dark emo",         label: "Emo",    swatch: "#ff3ad1",
    prompt: "a dark emo theme — near-black base with glowing magenta and purple accents, moody" },
  { key: "🌊  Deep ocean",       label: "Ocean",  swatch: "#1fd4c4",
    prompt: "a deep ocean theme — teal and aqua, blue-green ramp, soft glow" },
];

const $ = (id) => document.getElementById(id);

const els = {
  dropzone:  $("dropzone"),
  file:      $("file"),
  dzEmpty:   $("dz-empty"),
  dzLoaded:  $("dz-loaded"),
  dzPreview: $("dz-preview"),
  dzName:    $("dz-name"),
  dzClear:   $("dz-clear"),
  chips:     $("chips"),
  assetStrip:$("asset-strip"),
  prompt:    $("prompt"),
  toggle:    $("mode-toggle"),
  glider:    $("toggle-glider"),
  run:       $("run"),
  runHint:   $("run-hint"),
  imgIn:     $("img-in"),
  imgOut:    $("img-out"),
  badge:     $("badge"),
  status:    $("status"),
  download:  $("download"),
  loader:    $("frame-loader"),
  loaderText:$("loader-text"),
  frameEmpty:$("frame-empty"),
  gallery:   $("gallery"),
  serverDot: $("server-dot"),
  serverLbl: $("server-label"),
  silCanvas: $("sil-canvas"),
  wireOut: $("wire-out"),
};

/* draw the input's preserved silhouette (opaque pixels -> pale outline) into
   the SILHOUETTE LOCKED panel — the visual proof the shape never changes. */
function renderSilhouette(src) {
  const c = els.silCanvas;
  if (!c || !src) return;
  const img = new Image();
  img.onload = () => {
    const w = img.naturalWidth, h = img.naturalHeight;
    c.width = w; c.height = h;
    const ctx = c.getContext("2d");
    ctx.clearRect(0, 0, w, h);
    ctx.drawImage(img, 0, 0);
    const d = ctx.getImageData(0, 0, w, h), px = d.data;
    for (let i = 0; i < px.length; i += 4) {
      if (px[i + 3] >= 128) { px[i] = 206; px[i + 1] = 232; px[i + 2] = 255; px[i + 3] = 255; }
      else { px[i + 3] = 0; }
    }
    ctx.putImageData(d, 0, 0);
  };
  img.src = src;
}
function clearSilhouette() {
  const c = els.silCanvas; if (!c) return;
  const ctx = c.getContext("2d"); ctx && ctx.clearRect(0, 0, c.width, c.height);
}

const state = {
  imageDataUrl: null,   // base64 data URL of the loaded sprite
  fileName: null,
  theme: null,          // optional — null = use the prompt only
  mode: "exact",
  busy: false,
};

/* ------------------------------------------------------------ chips */
function buildChips() {
  THEMES.forEach((t) => {
    const b = document.createElement("button");
    b.type = "button";
    b.className = "chip";
    b.dataset.key = t.key;
    b.setAttribute("role", "option");
    b.innerHTML = `<span class="swatch" style="background:${t.swatch};color:${t.swatch}"></span>${t.label}`;
    b.addEventListener("click", () => selectTheme(t));
    els.chips.appendChild(b);
  });
}

function selectTheme(t) {
  if (state.theme === t.key) {               // re-click deselects — theme is optional
    state.theme = null;
    [...els.chips.children].forEach((c) => c.classList.remove("active"));
  } else {
    state.theme = t.key;
    els.prompt.value = t.prompt;             // theme is a prompt shortcut
    [...els.chips.children].forEach((c) => c.classList.toggle("active", c.dataset.key === t.key));
  }
  els.prompt.dispatchEvent(new Event("input"));
}

/* ------------------------------------------------------------ file loading */
function loadFile(file) {
  if (!file) return;
  if (!/image\//.test(file.type) && !/\.png$/i.test(file.name)) {
    setHint("please choose a PNG / image file", true);
    return;
  }
  const reader = new FileReader();
  reader.onload = (e) => {
    state.imageDataUrl = e.target.result;
    state.fileName = file.name;
    els.dzPreview.src = state.imageDataUrl;
    els.dzName.textContent = file.name;
    els.dzEmpty.hidden = true;
    els.dzLoaded.hidden = false;
    // mirror into the INPUT compare frame + silhouette panel immediately
    els.imgIn.src = state.imageDataUrl;
    renderSilhouette(state.imageDataUrl);
    refreshRun();
  };
  reader.readAsDataURL(file);
}

function clearFile() {
  state.imageDataUrl = null;
  state.fileName = null;
  els.file.value = "";
  els.dzEmpty.hidden = false;
  els.dzLoaded.hidden = true;
  els.imgIn.removeAttribute("src");
  clearSilhouette();
  refreshRun();
}

/* ------------------------------------------------------------ mode toggle */
function setMode(mode, btn) {
  state.mode = mode;
  [...els.toggle.querySelectorAll(".toggle-opt")].forEach((o) => {
    const on = o === btn;
    o.classList.toggle("active", on);
    o.setAttribute("aria-selected", String(on));
  });
  els.glider.classList.toggle("right", mode === "upscale2x");
  els.run.querySelector(".run-label").textContent =
    mode === "upscale2x" ? "▶ UPSCALE 2×" : "▶ RUN RETEXTURE";
}

/* ------------------------------------------------------------ run state */
function refreshRun() {
  const hasInstruction = !!state.theme || els.prompt.value.trim().length > 0;
  const ready = !!state.imageDataUrl && hasInstruction && !state.busy;
  els.run.disabled = !ready;
  if (!state.imageDataUrl) setHint("load a sprite to begin");
  else if (!hasInstruction) setHint("pick a theme or type a prompt");
  else if (!state.busy) setHint("ready · footprint stays locked");
}

function setHint(text, isError = false) {
  els.runHint.textContent = text;
  els.runHint.classList.toggle("error", isError);
}

function setBusy(on) {
  state.busy = on;
  els.run.classList.toggle("busy", on);
  els.run.disabled = on || !state.imageDataUrl;
  els.loader.hidden = !on;
  if (on) {
    els.frameEmpty.hidden = true;
    cycleLoaderText();
  }
}

let loaderTimer = null;
function cycleLoaderText() {
  const msgs = ["reading pixels…", "building footprint grammar…", "calling the model…", "locking the silhouette…", "rendering true-res PNG…"];
  let i = 0;
  els.loaderText.textContent = msgs[0];
  clearInterval(loaderTimer);
  loaderTimer = setInterval(() => {
    i = (i + 1) % msgs.length;
    if (state.busy) els.loaderText.textContent = msgs[i];
    else clearInterval(loaderTimer);
  }, 2200);
}

/* ------------------------------------------------------------ RUN -> /api/edit */
async function runEdit() {
  if (!state.imageDataUrl || state.busy) return;
  setBusy(true);
  setHint("working…");
  els.status.textContent = "running…";
  els.status.classList.remove("error");
  els.badge.hidden = true;
  els.download.hidden = true;

  const payload = {
    image: state.imageDataUrl,            // data URL; backend strips the prefix
    theme: state.theme,                   // resolves THEMES.get(theme_key)
    prompt: els.prompt.value.trim(),
    mode: state.mode,                     // "exact" | "upscale2x"
  };

  try {
    const res = await fetch("/api/edit", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(payload),
    });
    if (!res.ok) {
      const detail = await safeError(res);
      throw new Error(detail || `HTTP ${res.status}`);
    }
    const data = await res.json();
    renderResult(data);
  } catch (err) {
    els.status.textContent = "✗ " + (err.message || "edit failed");
    els.status.classList.add("error");
    setHint("try again", true);
  } finally {
    clearInterval(loaderTimer);
    setBusy(false);
    refreshRun();
  }
}

async function safeError(res) {
  try {
    const j = await res.json();
    return j.error || j.detail || j.message || j.status || "";
  } catch { return ""; }
}

function renderResult(data) {
  // Output image: accept several shapes for backend flexibility.
  const out = data.image || data.output || data.output_png || data.data_url;
  if (out) els.imgOut.src = normalizeDataUrl(out);
  if (data.input) els.imgIn.src = normalizeDataUrl(data.input);
  if (out) els.frameEmpty.hidden = true;

  // status line
  const footOk = (data.footprint_ok ?? data.fp_ok ?? data.footprint_perfect);
  const bits = [];
  if (data.width && data.height) bits.push(`${data.width}×${data.height}`);
  if (data.colors != null) bits.push(`${data.colors} colors`);
  if (data.latency != null) bits.push(`${Number(data.latency).toFixed(1)}s`);
  els.status.textContent = data.status || (bits.length ? bits.join("  ·  ") : "done");
  els.status.classList.remove("error");

  // badge
  if (footOk !== undefined && footOk !== null) {
    els.badge.hidden = false;
    if (footOk) {
      els.badge.textContent = "✓ silhouette preserved";
      els.badge.className = "badge ok";
    } else {
      els.badge.textContent = "⚠ silhouette changed";
      els.badge.className = "badge warn";
    }
  }

  // download
  if (out) {
    els.download.href = normalizeDataUrl(out);
    els.download.download = (state.fileName || "sprite").replace(/\.png$/i, "") + "_pixellock.png";
    els.download.hidden = false;
  }

  // show the model's raw text output (the "it's a language model" reveal)
  if (data.wire && els.wireOut) els.wireOut.textContent = data.wire;
}

function normalizeDataUrl(s) {
  if (typeof s !== "string") return s;
  if (s.startsWith("data:") || s.startsWith("http") || s.startsWith("/")) return s;
  return "data:image/png;base64," + s; // bare base64
}

/* ------------------------------------------------------------ gallery -> /api/examples */
const FALLBACK_EXAMPLES = [
  { id: "lava_trident", title: "Lava Trident", theme: "🌋  Molten lava",
    prompt: "Molten lava trident: glowing magma prongs with white-hot tips, charred black shaft, ember glow." },
  { id: "cosmic_cat", title: "Cosmic Cat", theme: "🌌  Cosmic galaxy",
    prompt: "Cosmic galaxy cat: deep space-purple fur speckled with tiny stars, glowing cyan eyes." },
  { id: "frozen_apple", title: "Frozen Apple", theme: "❄️  Frozen ice",
    prompt: "Frozen crystal apple: icy pale blue, frosted surface, glowing white highlight." },
  { id: "golden_rabbit", title: "Golden Rabbit", theme: "🪙  Solid gold",
    prompt: "Golden royal rabbit: shimmering gold fur with a soft cream belly, regal and warm." },
  { id: "autumn_bark", title: "Autumn Bark", theme: "🍂  Autumn dusk",
    prompt: "Autumn dusk bark: warm amber and crimson tones with deep purple shadows." },
  { id: "diamond_sword", title: "Diamond Sword", theme: "❄️  Frozen ice",
    prompt: "Diamond sword: pale icy-cyan crystal blade with white glints and a glowing aqua edge." },
];

async function loadGallery() {
  let examples = null;
  try {
    const res = await fetch("/api/examples", { method: "GET" });
    if (res.ok) {
      const data = await res.json();
      examples = Array.isArray(data) ? data : (data.examples || null);
    }
  } catch { /* offline / not wired yet */ }

  if (!examples || !examples.length) {
    examples = FALLBACK_EXAMPLES;
  }
  renderGallery(examples);
}

/* ------------------------------------------------------------ starter sprites */
async function loadAssets() {
  if (!els.assetStrip) return;
  try {
    const res = await fetch("/api/assets", { method: "GET" });
    if (!res.ok) throw new Error(`HTTP ${res.status}`);
    const assets = await res.json();
    renderAssets(Array.isArray(assets) ? assets : []);
  } catch {
    els.assetStrip.innerHTML = `<span class="asset-empty">starter sprites unavailable</span>`;
  }
}

function renderAssets(assets) {
  if (!els.assetStrip) return;
  els.assetStrip.innerHTML = "";
  if (!assets.length) {
    els.assetStrip.innerHTML = `<span class="asset-empty">no starter sprites found</span>`;
    return;
  }
  assets.forEach((asset) => {
    const btn = document.createElement("button");
    btn.type = "button";
    btn.className = "asset-tile";
    btn.innerHTML = `
      <span class="asset-img checker"><img class="pixelated" src="${normalizeDataUrl(asset.input)}" alt=""></span>
      <span class="asset-name">${escapeHtml(asset.title || asset.id || "sprite")}</span>`;
    btn.addEventListener("click", () => {
      state.imageDataUrl = normalizeDataUrl(asset.input);
      state.fileName = (asset.id || "starter") + ".png";
      els.dzPreview.src = state.imageDataUrl;
      els.dzName.textContent = state.fileName;
      els.dzEmpty.hidden = true;
      els.dzLoaded.hidden = false;
      els.imgIn.src = state.imageDataUrl;
      renderSilhouette(state.imageDataUrl);
      refreshRun();
    });
    els.assetStrip.appendChild(btn);
  });
}

function renderGallery(examples) {
  els.gallery.innerHTML = "";
  if (!examples.length) {
    els.gallery.innerHTML = `<p class="gallery-empty">no examples available</p>`;
    return;
  }
  examples.forEach((ex) => {
    const inputSrc = ex.input ? normalizeDataUrl(ex.input) : "";
    const outputSrc = ex.output ? normalizeDataUrl(ex.output) : "";
    const card = document.createElement("div");
    card.className = "card";
    card.tabIndex = 0;
    card.setAttribute("role", "button");
    card.innerHTML = `
      <div class="card-imgs">
        <div class="cell" data-tag="IN">${inputSrc ? `<img class="pixelated" src="${inputSrc}" alt="">` : ""}</div>
        <div class="cell" data-tag="OUT">${outputSrc ? `<img class="pixelated" src="${outputSrc}" alt="">` : ""}</div>
      </div>
      <p class="card-title">${escapeHtml(ex.title || ex.id || "example")}</p>
      <p class="card-prompt">${escapeHtml(ex.prompt || "")}</p>`;
    const activate = () => useExample(ex, inputSrc);
    card.addEventListener("click", activate);
    card.addEventListener("keydown", (e) => { if (e.key === "Enter" || e.key === " ") { e.preventDefault(); activate(); } });
    els.gallery.appendChild(card);
  });
}

function useExample(ex, inputSrc) {
  // load the input sprite into the lab
  if (inputSrc) {
    state.imageDataUrl = inputSrc;
    state.fileName = (ex.id || "example") + ".png";
    els.dzPreview.src = inputSrc;
    els.dzName.textContent = state.fileName;
    els.dzEmpty.hidden = true;
    els.dzLoaded.hidden = false;
    els.imgIn.src = inputSrc;
    renderSilhouette(inputSrc);
  }
  // prompt + theme
  if (ex.prompt) els.prompt.value = ex.prompt;
  if (ex.theme) {
    const match = THEMES.find((t) => t.key === ex.theme || t.label.toLowerCase() === String(ex.theme).toLowerCase());
    if (match) {
      state.theme = match.key;
      [...els.chips.children].forEach((c) => c.classList.toggle("active", c.dataset.key === match.key));
    }
  }
  if (ex.mode) setModeByValue(ex.mode);
  refreshRun();
  document.querySelector(".lab")?.scrollIntoView({ behavior: "smooth", block: "start" });
}

function setModeByValue(mode) {
  const want = mode === "upscale2x" || /upscale/i.test(mode) ? "upscale2x" : "exact";
  const btn = els.toggle.querySelector(`.toggle-opt[data-mode="${want}"]`);
  if (btn) setMode(want, btn);
}

function escapeHtml(s) {
  return String(s).replace(/[&<>"']/g, (c) =>
    ({ "&": "&amp;", "<": "&lt;", ">": "&gt;", '"': "&quot;", "'": "&#39;" }[c]));
}

/* ------------------------------------------------------------ server status */
async function pingServer() {
  try {
    const res = await fetch("/api/health", { method: "GET" });
    if (res.ok) {
      const data = await res.json();
      setServer(Boolean(data.model_online), data.model_online ? "online" : "model waking");
      return;
    }
  } catch { /* fall through */ }
  // /api/examples succeeding also means the app server is up
  try {
    const res = await fetch("/api/examples", { method: "GET" });
    setServer(res.ok, res.ok ? "ui online" : "offline");
  } catch { setServer(false, "offline"); }
}

function setServer(up, label) {
  els.serverDot.className = "dot " + (up ? "up" : "down");
  els.serverLbl.textContent = label || (up ? "online" : "offline");
}

/* ------------------------------------------------------------ wire up DOM */
function init() {
  buildChips();
  // no default theme — it's optional; the user can just type a prompt

  // dropzone
  els.dropzone.addEventListener("click", (e) => {
    if (e.target.closest(".link-btn")) return; // "change" handled separately
    els.file.click();
  });
  els.dropzone.addEventListener("keydown", (e) => {
    if (e.key === "Enter" || e.key === " ") { e.preventDefault(); els.file.click(); }
  });
  els.file.addEventListener("change", (e) => loadFile(e.target.files[0]));
  els.dzClear.addEventListener("click", (e) => { e.stopPropagation(); clearFile(); });

  ["dragenter", "dragover"].forEach((ev) =>
    els.dropzone.addEventListener(ev, (e) => { e.preventDefault(); els.dropzone.classList.add("dragover"); }));
  ["dragleave", "drop"].forEach((ev) =>
    els.dropzone.addEventListener(ev, (e) => { e.preventDefault(); els.dropzone.classList.remove("dragover"); }));
  els.dropzone.addEventListener("drop", (e) => {
    const f = e.dataTransfer && e.dataTransfer.files && e.dataTransfer.files[0];
    if (f) loadFile(f);
  });
  // paste an image from clipboard
  window.addEventListener("paste", (e) => {
    const item = [...(e.clipboardData?.items || [])].find((i) => i.type.startsWith("image/"));
    if (item) loadFile(item.getAsFile());
  });

  // mode toggle
  els.toggle.querySelectorAll(".toggle-opt").forEach((btn) =>
    btn.addEventListener("click", () => setMode(btn.dataset.mode, btn)));

  // prompt edits clear active chip only if it diverges (keeps it simple: leave chip, prompt is source of truth)
  els.prompt.addEventListener("input", refreshRun);

  // run
  els.run.addEventListener("click", runEdit);
  // ctrl/cmd+enter to run
  window.addEventListener("keydown", (e) => {
    if ((e.ctrlKey || e.metaKey) && e.key === "Enter" && !els.run.disabled) runEdit();
  });

  refreshRun();
  loadAssets();
  loadGallery();
  pingServer();
}

if (document.readyState === "loading") document.addEventListener("DOMContentLoaded", init);
else init();