// Anchor manager & friend tags (spec M13, lane F).
//
// A collapsible panel (pre-wired container #anchor-panel, toggle #btn-anchors) listing every
// anchor in state.anchors: color dot (recolor), label (rename), jump-to (scene3d.focusOn),
// delete. Mutations go through PATCH/DELETE ${state.apiBase}/api/anchors/{id}; after any
// mutation we update state.anchors and emit("anchors-changed") so scene3d + the video
// overlays refresh (main.js wires that event to scene3d.refreshAnchors; overlays read
// state.anchors every frame).
//
// ＋ Tag (friend tags): drives the FROZEN M8 annotation flow WITHOUT an event.
// annotate.js was written null-event safe on purpose: startAnnotateMode() only needs the
// registered cells, and _submit POSTs /api/annotations with event_id: null, which the backend
// resolves to an INDEPENDENT anchor ("Annotations with no event stay independent").
// Flow: prompt for the friend's name -> annotator.close() (clears any currentEvent) ->
// annotator.startAnnotateMode() -> the user drags a bbox over the friend on any video ->
// the resolved anchor arrives via emit("anchors-changed", anchor) -> we PATCH the pending
// name + a palette color onto it and stop annotate mode. Esc (or ＋ Tag again) cancels.
//
// Capsule mode (contract #5): every MUTATING control carries class="write-ui" so a baked
// bundle hides it; the read-only list + jump-to stay available.

import { state, emit, on } from "./state.js";
import { scene3d } from "./scene3d.js";
import { annotator } from "./annotate.js";

const DEFAULT_COLOR = "#59d499";
// Friendly tag palette (mirrors the scene's per-video accent hues).
const TAG_COLORS = ["#ff5d73", "#4dd0ff", "#c9a2ff", "#ffcf5d", "#7dffb0", "#ff9d5d"];

const CSS = `
  #anchor-panel {
    position: absolute; top: 3.1rem; left: 0.6rem; width: 244px; z-index: 7;
    background: rgba(15,20,32,0.94); border: 1px solid var(--border); border-radius: 9px;
    font-size: 0.78rem; box-shadow: 0 8px 26px rgba(0,0,0,0.5); backdrop-filter: blur(5px);
    max-height: min(60vh, 420px); display: flex; flex-direction: column;
  }
  .anch-head {
    display: flex; align-items: center; gap: 0.4rem; padding: 0.45rem 0.55rem;
    border-bottom: 1px solid var(--border); flex: 0 0 auto;
  }
  .anch-head strong { flex: 1 1 auto; font-size: 0.8rem; }
  .anch-n { color: var(--dim); font-weight: 400; }
  .anch-x {
    background: none; border: none; color: var(--dim); cursor: pointer;
    font-size: 0.85rem; padding: 0 0.2rem;
  }
  .anch-x:hover { color: var(--text); }
  .anch-hint { padding: 0.3rem 0.55rem 0; line-height: 1.35; min-height: 0; flex: 0 0 auto; }
  .anch-hint:empty { display: none; }
  .anch-list {
    padding: 0.4rem 0.45rem 0.5rem; overflow-y: auto; display: flex;
    flex-direction: column; gap: 0.12rem; flex: 1 1 auto;
  }
  .anch-empty { color: var(--dim); padding: 0.1rem 0.15rem 0.2rem; line-height: 1.4; }
  .anch-row {
    display: flex; align-items: center; gap: 0.4rem; padding: 0.22rem 0.3rem;
    border-radius: 6px;
  }
  .anch-row:hover { background: rgba(255,255,255,0.05); }
  .anch-dot {
    width: 12px; height: 12px; border-radius: 4px; flex: 0 0 auto; position: relative;
    box-shadow: 0 0 0 1px rgba(0,0,0,0.4);
  }
  .anch-color {
    position: absolute; inset: 0; opacity: 0; width: 100%; height: 100%;
    cursor: pointer; padding: 0; border: none;
  }
  .anch-label {
    flex: 1 1 auto; white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
    cursor: pointer;
  }
  .anch-label:hover { color: var(--accent); }
  .anch-btn {
    background: none; border: none; color: var(--dim); cursor: pointer;
    font-size: 0.78rem; padding: 0 0.15rem; flex: 0 0 auto; line-height: 1;
  }
  .anch-btn:hover { color: var(--text); }
  .anch-del:hover { color: var(--bad); }
`;

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

async function patchAnchor(id, body) {
  const resp = await fetch(`${state.apiBase}/api/anchors/${id}`, {
    method: "PATCH",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(body),
  });
  if (!resp.ok) throw new Error(`HTTP ${resp.status}`);
  return resp.json();
}

/** Replace (or append) an anchor in state.anchors and notify every consumer. */
function upsertIntoState(anchor) {
  const i = state.anchors.findIndex((a) => a.id === anchor.id);
  if (i >= 0) state.anchors[i] = anchor;
  else state.anchors.push(anchor);
  emit("anchors-changed", anchor);
}

export const anchorPanel = {
  ready: false,
  open: false,
  _panel: null,
  _btn: null,
  _pendingTag: null, // { name, color, knownIds:Set<number> } while a friend tag is in flight

  init() {
    this._btn = document.getElementById("btn-anchors");
    this._panel = document.getElementById("anchor-panel");
    if (!this._btn || !this._panel) return; // pre-wired DOM missing — stay hidden, degrade

    const style = document.createElement("style");
    style.textContent = CSS;
    document.head.appendChild(style);

    this._panel.innerHTML = `
      <div class="anch-head">
        <strong>⚓ Anchors <span class="anch-n"></span></strong>
        <button class="btn anch-tag write-ui" title="Tag a friend: drag a box over them on any video">＋ Tag</button>
        <button class="anch-x" title="Collapse">✕</button>
      </div>
      <div class="anch-hint dim"></div>
      <div class="anch-list"></div>`;

    this._panel.querySelector(".anch-x").addEventListener("click", () => this.toggle(false));
    this._panel.querySelector(".anch-tag").addEventListener("click", () => {
      if (this._pendingTag) this._cancelTag();
      else this._startTag();
    });
    this._btn.addEventListener("click", () => this.toggle());

    // Any anchor mutation anywhere (this panel, annotate.js, a pending friend tag resolving).
    on("anchors-changed", (payload) => this._onAnchorsChanged(payload));

    // Esc cancels a pending tag (main.js also maps Esc to free-roam; both are fine together).
    window.addEventListener("keydown", (e) => {
      if (e.code === "Escape" && this._pendingTag) this._cancelTag();
    });

    this._render();
    this._btn.style.display = ""; // unhide: the module is live
    this.ready = true;
  },

  toggle(force) {
    if (!this._panel) return;
    this.open = force != null ? !!force : !this.open;
    this._panel.style.display = this.open ? "" : "none";
    this._btn?.classList.toggle("active", this.open);
    if (this.open) this._render();
  },

  // --- friend tag flow ------------------------------------------------------------------

  _startTag() {
    let name;
    try {
      name = window.prompt("Friend's name:", "");
    } catch {
      name = null; // prompt() unavailable (headless) — nothing to do
    }
    name = (name || "").trim();
    if (!name) return;
    const color = TAG_COLORS[state.anchors.length % TAG_COLORS.length];
    this._pendingTag = { name, color, knownIds: new Set(state.anchors.map((a) => a.id)) };
    try {
      annotator.close(); // clear any currentEvent so the annotation POSTs event_id: null
      annotator.startAnnotateMode();
    } catch (err) {
      console.warn("[anchorPanel] could not start annotate mode", err);
      this._pendingTag = null;
      this._hint(`<span class="bad">tag mode failed: ${esc(err.message)}</span>`);
      return;
    }
    this._tagButton(true);
    this._hint(`drag a box over <b>${esc(name)}</b> on any video · Esc cancels`);
    this.toggle(true);
  },

  _cancelTag() {
    this._pendingTag = null;
    try {
      annotator.stopAnnotateMode();
    } catch {
      /* already stopped */
    }
    this._tagButton(false);
    this._hint("");
  },

  _tagButton(active) {
    const b = this._panel?.querySelector(".anch-tag");
    if (!b) return;
    b.textContent = active ? "✕ Cancel" : "＋ Tag";
    b.classList.toggle("active", active);
  },

  _onAnchorsChanged(payload) {
    const tag = this._pendingTag;
    if (tag && payload && payload.id != null && !tag.knownIds.has(payload.id)) {
      // The bbox the user just drew resolved into a brand-new anchor: name + color it.
      this._pendingTag = null;
      this._finishTag(tag, payload);
    }
    this._render();
  },

  async _finishTag(tag, anchor) {
    try {
      annotator.stopAnnotateMode();
    } catch {
      /* fine */
    }
    this._tagButton(false);
    try {
      const updated = await patchAnchor(anchor.id, { label: tag.name, color: tag.color });
      upsertIntoState(updated);
      this._hint(`tagged <b>${esc(tag.name)}</b> — visible in 3D and on every video`);
    } catch (err) {
      this._hint(`<span class="bad">naming the tag failed: ${esc(err.message)}</span>`);
    }
  },

  // --- list rendering + row actions ------------------------------------------------------

  _hint(html) {
    const h = this._panel?.querySelector(".anch-hint");
    if (h) h.innerHTML = html;
  },

  _render() {
    if (!this._panel) return;
    const n = this._panel.querySelector(".anch-n");
    if (n) n.textContent = `(${state.anchors.length})`;
    const list = this._panel.querySelector(".anch-list");
    if (!list) return;
    if (state.anchors.length === 0) {
      list.innerHTML =
        `<div class="anch-empty">no anchors yet — <b>＋ Tag</b> a friend,` +
        ` or annotate an event on the timeline</div>`;
      return;
    }
    list.innerHTML = state.anchors
      .map((a) => {
        const color = a.color || DEFAULT_COLOR;
        return (
          `<div class="anch-row" data-id="${a.id}">` +
          `<span class="anch-dot" style="background:${esc(color)}">` +
          `<input type="color" class="anch-color write-ui" value="${esc(color)}" title="Recolor"></span>` +
          `<span class="anch-label" title="Jump to ${esc(a.label || "anchor")}">${esc(a.label) || "(unnamed)"}</span>` +
          `<button class="anch-btn anch-jump" title="Jump to in 3D">◎</button>` +
          `<button class="anch-btn anch-rename write-ui" title="Rename">✎</button>` +
          `<button class="anch-btn anch-del write-ui" title="Delete">✕</button></div>`
        );
      })
      .join("");
    for (const row of list.querySelectorAll(".anch-row")) {
      const id = Number(row.dataset.id);
      row.querySelector(".anch-jump").addEventListener("click", () => this._jump(id));
      row.querySelector(".anch-label").addEventListener("click", () => this._jump(id));
      row.querySelector(".anch-rename").addEventListener("click", () => this._rename(id));
      row.querySelector(".anch-del").addEventListener("click", () => this._delete(id));
      const colorInput = row.querySelector(".anch-color");
      // Live-preview the dot while the picker is open; PATCH once on commit.
      colorInput.addEventListener("input", () => {
        row.querySelector(".anch-dot").style.background = colorInput.value;
      });
      colorInput.addEventListener("change", () => this._recolor(id, colorInput.value));
    }
  },

  _find(id) {
    return state.anchors.find((a) => a.id === id);
  },

  _jump(id) {
    const a = this._find(id);
    if (!a) return;
    try {
      scene3d.focusOn(a.x, a.y, a.z);
    } catch (err) {
      console.warn("[anchorPanel] focusOn failed", err);
    }
  },

  async _rename(id) {
    const a = this._find(id);
    if (!a) return;
    let name;
    try {
      name = window.prompt("Rename anchor:", a.label || "");
    } catch {
      name = null;
    }
    if (name == null) return; // cancelled
    name = name.trim();
    if (!name || name === a.label) return;
    try {
      upsertIntoState(await patchAnchor(id, { label: name }));
    } catch (err) {
      this._hint(`<span class="bad">rename failed: ${esc(err.message)}</span>`);
    }
  },

  async _recolor(id, color) {
    if (!this._find(id)) return;
    try {
      upsertIntoState(await patchAnchor(id, { color }));
    } catch (err) {
      this._hint(`<span class="bad">recolor failed: ${esc(err.message)}</span>`);
      this._render(); // roll the previewed dot back to the stored color
    }
  },

  async _delete(id) {
    try {
      const resp = await fetch(`${state.apiBase}/api/anchors/${id}`, { method: "DELETE" });
      if (!resp.ok) throw new Error(`HTTP ${resp.status}`);
      const i = state.anchors.findIndex((a) => a.id === id);
      if (i >= 0) state.anchors.splice(i, 1);
      emit("anchors-changed", null);
    } catch (err) {
      this._hint(`<span class="bad">delete failed: ${esc(err.message)}</span>`);
    }
  },
};