import { CONFIG } from "./config.js";
import { Store } from "./store.js";
import { Bag } from "./bag.js";
import { TRACKS } from "./tracks.js";
import { fetchAllSpacesWithRetry } from "./api.js";
import { mountCard } from "./embed.js";
import * as ui from "./ui.js";
import { initOAuth, signIn, signOut, likeOnHf } from "./oauth.js";

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

const state = {
  store: new Store({ key: CONFIG.storageKey }),
  all: [],            // all view models
  byId: new Map(),
  bag: null,
  filterTrack: null,  // null | "Backyard" | "Wood"
  current: null,      // current vm
  controller: null,   // mountCard controller
  oauth: null,
};

function idsForTrack(track) {
  const list = track ? state.all.filter((v) => v.track === track) : state.all;
  return list.map((v) => v.id);
}
function eligibleIds() { return idsForTrack(state.filterTrack); }

function prefetchNext() {
  if (!CONFIG.prefetchNext || !state.bag) return;
  const peekId = state.bag.bag[state.bag.cursor];
  const vm = peekId && state.byId.get(peekId);
  if (!vm) return;
  let link = document.getElementById("prefetch-link");
  if (!link) {
    link = document.createElement("link");
    link.id = "prefetch-link";
    link.rel = "preconnect";
    document.head.append(link);
  }
  link.href = vm.embedUrl;
}

function show(vm) {
  if (!vm) return;
  state.controller?.destroy();
  state.current = vm;
  state.store.markSeen(vm.id);
  ui.renderCard(vm, state.store);
  ui.setProgress(state.bag.progress());
  state.controller = mountCard($("stage"), vm, { onSkip: next });
  if (CONFIG.resumeRound) state.store.saveRound({ ...state.bag.serialize(), track: state.filterTrack });
  prefetchNext();
}

function next() { show(state.byId.get(state.bag.next())); }
function prev() { const id = state.bag.prev(); if (id) show(state.byId.get(id)); }

function cycleTrack() {
  const order = [null, ...TRACKS];
  const nextTrack = order[(order.indexOf(state.filterTrack) + 1) % order.length];
  const ids = idsForTrack(nextTrack);
  if (!ids.length) { ui.toast(`No spaces in ${nextTrack}`); return; }
  state.filterTrack = nextTrack;
  ui.setTrackFilterLabel(state.filterTrack);
  state.bag.setIds(ids);
  next();
}

function wireKeys() {
  document.addEventListener("keydown", (e) => {
    const tag = e.target.tagName;
    if (tag === "INPUT" || tag === "TEXTAREA") return;
    switch (e.key) {
      case " ": case "ArrowRight": e.preventDefault(); next(); break;
      case "ArrowLeft": prev(); break;
      case "l": case "L": $("btn-like").click(); break;
      case "s": case "S": $("btn-save").click(); break;
      case "o": case "O": if (state.current) window.open(state.current.hfUrl, "_blank"); break;
      case "?": ui.showShortcuts(); break;
    }
  });
}

function wireButtons() {
  $("btn-next").onclick = next;
  $("btn-prev").onclick = prev;
  $("btn-track").onclick = cycleTrack;
  ui.setTrackFilterLabel(null);

  $("btn-save").onclick = () => {
    if (!state.current) return;
    const on = state.store.toggleSaved(state.current.id);
    ui.setSaveState(on);
    ui.setSavedCount(state.store.savedIds().length);
    ui.toast(on ? "Saved 💾" : "Removed from saved");
  };

  $("btn-saved").onclick = () => {
    const vms = state.store.savedIds().map((id) => state.byId.get(id)).filter(Boolean);
    ui.openDrawer(vms, {
      onOpenHere: (id) => { $("drawer").hidden = true; show(state.byId.get(id)); },
      onUnsave: (id) => { state.store.toggleSaved(id); ui.setSavedCount(state.store.savedIds().length); },
    });
  };
  ui.setSavedCount(state.store.savedIds().length);

  $("btn-like").onclick = async () => {
    const vm = state.current;
    if (!vm) return;
    const turningOn = !state.store.isLiked(vm.id);
    ui.setLikeState(turningOn); // optimistic
    const where = await likeOnHf(vm.id, turningOn, state.oauth?.accessToken);
    if (where === "hf") {
      state.store.setHfLiked(vm.id, turningOn);
      vm.likes = Math.max(0, (vm.likes || 0) + (turningOn ? 1 : -1));
      ui.setHfLikes(vm.likes);
      ui.toast(turningOn ? "Liked on Hugging Face 💚" : "Unliked");
    } else {
      state.store.setLocalLiked(vm.id, turningOn);
      ui.toast(state.oauth
        ? "Couldn't like on HF — saved locally. Open on HF to like officially ↗"
        : "Saved your like locally — sign in to like on HF ↗");
    }
  };
}

function renderAuth() {
  ui.renderAuth(state.oauth?.userInfo, {
    onSignIn: signIn,
    onSignOut: () => { signOut(); state.oauth = null; renderAuth(); },
  });
}

function showError(msg) {
  $("stage").innerHTML = `<div class="fallback"><strong>${msg}</strong>
    <div class="fallback-actions">
      <a class="btn" target="_blank" rel="noopener" href="${CONFIG.apiBase}/${CONFIG.org}">Visit the org ↗</a>
      <button class="btn btn-ghost" onclick="location.reload()">Retry</button>
    </div></div>`;
}

async function boot() {
  wireKeys();
  wireButtons();

  try {
    state.all = await fetchAllSpacesWithRetry();
  } catch {
    showError("Couldn't reach the Hugging Face API. Check your connection and retry.");
    return;
  }
  if (!state.all.length) { showError("No projects found on the trail yet."); return; }
  state.byId = new Map(state.all.map((v) => [v.id, v]));

  state.oauth = await initOAuth();
  renderAuth();

  const saved = CONFIG.resumeRound ? state.store.loadRound() : null;
  state.filterTrack = saved?.track ?? null;
  ui.setTrackFilterLabel(state.filterTrack);
  const canResume = saved && saved.track === state.filterTrack;
  state.bag = new Bag(eligibleIds(), { state: canResume ? saved : null });
  next();

  if (!localStorage.getItem("bsr:hinted")) {
    ui.toast("Spot a project · 👍 like · 💾 save · 🧭 Next (or hit Space). Press ? for keys.", 6000);
    localStorage.setItem("bsr:hinted", "1");
  }
}

boot();