let ownedNfts = [];
let ownedNftRows = [];
let selectedNftKey = "";
let nftsLoadId = 0;
let nftsLoading = false;
let nftsPage = 1;
let nftsCachingVisible = false;
const NFTS_PAGE_SIZE = 30;
const nftMetadataCache = new Map();

function nftKey(nft) {
  return `${String(nft.nft_name || nft.asset || "").trim().toLowerCase()}|${Number(nft.series || nft.nft_series || 0)}`;
}

function nftCacheKey(nft) {
  return `${String(nft.nft_name || nft.asset || "").trim().toLowerCase()}_${Number(nft.series || nft.nft_series || 0)}`;
}

function escapeNftText(value) {
  return String(value ?? "")
    .replaceAll("&", "&")
    .replaceAll("<", "&lt;")
    .replaceAll(">", "&gt;")
    .replaceAll('"', "&quot;")
    .replaceAll("'", "&#039;");
}

function shortenNftTx(txid) {
  const value = String(txid || "");
  return value.length > 16 ? `${value.slice(0, 6)}...${value.slice(-8)}` : value || "--";
}

function nftDisplayName(nft) {
  const metadataName = String(nft.metadata?.name || "").trim();
  if (metadataName) {
    return metadataName;
  }
  const name = String(nft.nft_name || nft.asset || "NFT").trim();
  return Number(nft.series || 0) > 0 ? `${name} #${Number(nft.series)}` : name;
}

function nftImageUri(nft) {
  const cachedImage = String(nft.image_data_url || nft.imageDataUrl || "").trim();
  if (cachedImage) {
    return cachedImage;
  }
  return String(
    nft.metadata?.image
      || nft.metadata?.image_url
      || nft.metadata?.animation_url
      || ""
  ).trim();
}

function normalizeIpfsGateway(gateway) {
  const fallback = "https://gateway.pinata.cloud/ipfs/";
  const clean = String(gateway || "").trim() || fallback;
  return clean.endsWith("/") ? clean : `${clean}/`;
}

function normalizeIpfsPath(value) {
  let path = String(value || "").trim();
  let previous = "";
  while (path && path !== previous) {
    previous = path;
    path = path
      .replace(/^ipfs:\/\//i, "")
      .replace(/^ipfs:\//i, "")
      .replace(/^ipfs:/i, "")
      .replace(/^\/?ipfs\//i, "")
      .replace(/^\/+/, "");
  }
  return path;
}

function ipfsToGatewayUrl(uri, gateway) {
  const value = String(uri || "").trim();
  if (!value) {
    return "";
  }
  if (value.startsWith("http://") || value.startsWith("https://")) {
    return value;
  }
  if (value.startsWith("data:image/")) {
    return value;
  }
  const path = normalizeIpfsPath(value);
  return `${normalizeIpfsGateway(gateway)}${path}`;
}

function nftTypeLabel(nft) {
  const metadataType = String(nft.metadata?.contractless?.metadata_type || "").trim();
  if (metadataType.toLowerCase() === "rwa") {
    return "RWA";
  }
  if (nftImageUri(nft)) {
    return "Image NFT";
  }
  return "NFT";
}

function setNftsState(message) {
  if (nftsState) {
    nftsState.textContent = message || "";
  }
}

function setNftDetailText(element, value) {
  if (element) {
    element.textContent = value || "--";
  }
}

function resetNftDetails(message = "Select an owned NFT.") {
  if (nftDetailTitle) {
    nftDetailTitle.textContent = "NFT Details";
  }
  if (nftDetailSubtitle) {
    nftDetailSubtitle.textContent = message;
  }
  setNftDetailText(nftDetailName, "");
  setNftDetailText(nftDetailAsset, "");
  setNftDetailText(nftDetailCreator, "");
  setNftDetailText(nftDetailGenesis, "");
  setNftDetailText(nftDetailMetadata, "");
  if (nftMetadataSummary) {
    nftMetadataSummary.innerHTML = "";
  }
  if (nftHistory) {
    nftHistory.innerHTML = "";
  }
}

function hasOwnedBalance(balance) {
  try {
    return BigInt(String(balance?.balance || "0")) > 0n;
  } catch (_) {
    return Number(balance?.balance || 0) > 0;
  }
}

function ownedNftRowsFromBalances(balances, registry) {
  const normalizedBalances = Array.isArray(balances) ? balances : [];
  const registryRows = Array.isArray(registry) ? registry : [];
  const balanceByAsset = new Map();
  normalizedBalances.forEach((balance) => {
    if (!hasOwnedBalance(balance)) {
      return;
    }
    const asset = String(balance.asset || "").trim().toLowerCase();
    const series = Number(balance.nft_series || 0);
    balanceByAsset.set(`${asset}|${series}`, balance);
  });

  return registryRows
    .map((nft) => {
      const nftName = String(nft.nft_name || "").trim();
      const series = Number(nft.series || 0);
      const balance = balanceByAsset.get(`${nftName.toLowerCase()}|${series}`);
      if (!balance) {
        return null;
      }
      return {
        asset: nftName,
        nft_name: nftName,
        series,
        balance: String(balance.balance || "0"),
        origin_txid: nft.origin_txid || ""
      };
    })
    .filter(Boolean)
    .filter((nft) => nft.nft_name);
}

function legacyOwnedNftRowsFromBalances(balances) {
  return (Array.isArray(balances) ? balances : [])
    .filter((balance) => {
      const series = Number(balance.nft_series || 0);
      let owned = false;
      try {
        owned = BigInt(String(balance.balance || "0")) > 0n;
      } catch (_) {
        owned = Number(balance.balance || 0) > 0;
      }
      return series > 0 && owned;
    })
    .map((balance) => ({
      asset: String(balance.asset || "").trim(),
      nft_name: String(balance.asset || "").trim(),
      series: Number(balance.nft_series || 0),
      balance: String(balance.balance || "0")
    }))
    .filter((nft) => nft.nft_name);
}

function metadataDescription(metadata) {
  return String(metadata?.description || metadata?.summary || "").trim();
}

function renderNftCard(nft) {
  const key = nftKey(nft);
  const name = nftDisplayName(nft);
  const image = nftImageUri(nft);
  const type = nftTypeLabel(nft);
  const active = key === selectedNftKey ? " active" : "";
  const preview = image && nft.gateway
    ? `<img src="${escapeNftText(ipfsToGatewayUrl(image, nft.gateway))}" alt="">`
    : `<div class="asset-mark art">${escapeNftText(assetInitial(name))}</div>`;

  return `
    <article class="nft-record${active}" data-nft-key="${escapeNftText(key)}">
      <div class="nft-card-media">${preview}</div>
      <div class="nft-record-top">
        <div>
          <strong>${escapeNftText(name)}</strong>
          <span>${escapeNftText(type)} - ${escapeNftText(nft.asset_name || `${nft.nft_name}_${nft.series}`)}</span>
        </div>
      </div>
      <div class="nft-link-row">
        <span>Metadata</span>
        <code>${escapeNftText(nft.metadata_uri || nft.item_ipfs || "--")}</code>
      </div>
      <div class="nft-actions">
        <button class="secondary-button" type="button" data-nft-select="${escapeNftText(key)}">View Details</button>
      </div>
    </article>
  `;
}

function renderNftHistoryEntry(entry) {
  const asset = entry.received_asset
    ? `${entry.received_asset}${Number(entry.received_series || 0) > 0 ? ` #${entry.received_series}` : ""}`
    : "";
  return `
    <div class="nft-history-row">
      <div>
        <b>${escapeNftText(entry.action || "Unknown")}</b>
        <span>Block ${escapeNftText(formatNumber(entry.block || 0))}</span>
      </div>
      <code>${escapeNftText(shortenNftTx(entry.txid || ""))}</code>
      ${entry.from ? `<div><span>From</span><strong>${escapeNftText(shortenAddress(entry.from))}</strong></div>` : ""}
      ${entry.to ? `<div><span>To</span><strong>${escapeNftText(shortenAddress(entry.to))}</strong></div>` : ""}
      ${asset ? `<div><span>Received</span><strong>${escapeNftText(asset)}</strong></div>` : ""}
    </div>
  `;
}

function renderNftMetadataSummary(nft) {
  const metadata = nft.metadata || {};
  const description = metadataDescription(metadata);
  const attributes = Array.isArray(metadata.attributes) ? metadata.attributes : [];
  const contractless = metadata.contractless && typeof metadata.contractless === "object"
    ? metadata.contractless
    : null;

  const parts = [];
  if (description) {
    parts.push(`<p>${escapeNftText(description)}</p>`);
  }
  if (attributes.length) {
    parts.push(`
      <div class="nft-attributes">
        ${attributes.slice(0, 8).map((attribute) => `
          <div>
            <span>${escapeNftText(attribute.trait_type || attribute.type || "Trait")}</span>
            <b>${escapeNftText(attribute.value ?? "")}</b>
          </div>
        `).join("")}
      </div>
    `);
  }
  if (contractless) {
    parts.push(`
      <div class="nft-rwa-fields">
        ${Object.entries(contractless).slice(0, 6).map(([key, value]) => `
          <div><span>${escapeNftText(key)}</span><b>${escapeNftText(value)}</b></div>
        `).join("")}
      </div>
    `);
  }
  return parts.join("") || "<p>No metadata summary available.</p>";
}

function renderNftDetails(nft) {
  if (!nft) {
    resetNftDetails();
    return;
  }

  const name = nftDisplayName(nft);
  if (nftDetailTitle) {
    nftDetailTitle.textContent = name;
  }
  if (nftDetailSubtitle) {
    nftDetailSubtitle.textContent = nftTypeLabel(nft);
  }

  setNftDetailText(nftDetailName, name);
  setNftDetailText(nftDetailAsset, nft.asset_name || `${nft.nft_name}_${nft.series}`);
  setNftDetailText(nftDetailCreator, nft.creator ? shortenAddress(nft.creator) : "");
  setNftDetailText(nftDetailGenesis, nft.genesis_txid ? shortenNftTx(nft.genesis_txid) : "");
  setNftDetailText(nftDetailMetadata, nft.metadata_uri || nft.item_ipfs || "");

  if (nftMetadataSummary) {
    nftMetadataSummary.innerHTML = renderNftMetadataSummary(nft);
  }
  if (nftHistory) {
    nftHistory.innerHTML = Array.isArray(nft.history) && nft.history.length
      ? nft.history.map(renderNftHistoryEntry).join("")
      : '<div class="nft-history-empty">No provenance records returned.</div>';
  }
}

function renderNftsPage() {
  if (!nftsList) {
    return;
  }
  nftsList.innerHTML = ownedNfts.map(renderNftCard).join("");
  const selected = ownedNfts.find((nft) => nftKey(nft) === selectedNftKey) || ownedNfts[0];
  selectedNftKey = selected ? nftKey(selected) : "";
  renderNftDetails(selected);

  if (!walletLoaded) {
    setNftsState("Load a wallet to view NFTs.");
  } else if (!ownedNftRows.length) {
    setNftsState(nftsLoading ? "Loading owned NFTs..." : "No owned NFTs found for this address.");
  } else if (!ownedNfts.length) {
    const start = (nftsPage - 1) * NFTS_PAGE_SIZE + 1;
    const end = Math.min(start + NFTS_PAGE_SIZE - 1, ownedNftRows.length);
    const suffix = nftsCachingVisible ? " - Caching media..." : "";
    setNftsState(`Loading ${start}-${end} of ${ownedNftRows.length} NFTs${suffix}`);
  } else {
    const start = (nftsPage - 1) * NFTS_PAGE_SIZE + 1;
    const end = Math.min(start + ownedNfts.length - 1, ownedNftRows.length);
    const suffix = nftsCachingVisible ? " - Caching media..." : "";
    setNftsState(`Showing ${start}-${end} of ${ownedNftRows.length} NFTs${suffix}`);
  }
  renderNftsPagination();
}

async function loadNftMetadata(invoke, detail, gateway) {
  const metadataUri = detail.metadata_uri || detail.item_ipfs || "";
  if (!metadataUri) {
    return null;
  }
  const cacheKey = `${gateway}|${metadataUri}`;
  if (nftMetadataCache.has(cacheKey)) {
    return nftMetadataCache.get(cacheKey);
  }
  const metadata = await invoke("fetch_ipfs_metadata", {
    ipfsPath: metadataUri,
    gateway
  });
  nftMetadataCache.set(cacheKey, metadata);
  return metadata;
}

function nftFromCache(row, cached, gateway) {
  const detail = cached?.detail && typeof cached.detail === "object" ? cached.detail : {};
  const metadata = cached?.metadata && typeof cached.metadata === "object" ? cached.metadata : {};
  return {
    ...row,
    ...detail,
    metadata,
    image_data_url: cached?.image_data_url || "",
    gateway
  };
}

function renderNftsPagination() {
  if (!nftsPagination) {
    return;
  }
  const totalPages = Math.max(1, Math.ceil(ownedNftRows.length / NFTS_PAGE_SIZE));
  const showPagination = ownedNftRows.length > NFTS_PAGE_SIZE;
  nftsPagination.hidden = !showPagination;
  if (nftsPageTotal) {
    nftsPageTotal.textContent = String(totalPages);
  }
  if (nftsPageInput && Number(nftsPageInput.value) !== nftsPage) {
    nftsPageInput.value = String(nftsPage);
  }
  document.querySelectorAll("[data-nfts-page]").forEach((button) => {
    const action = button.dataset.nftsPage;
    button.disabled = !showPagination
      || (["first", "previous"].includes(action) && nftsPage <= 1)
      || (["next", "last"].includes(action) && nftsPage >= totalPages);
  });
}

function clampNftsPage(page) {
  const totalPages = Math.max(1, Math.ceil(ownedNftRows.length / NFTS_PAGE_SIZE));
  return Math.min(Math.max(1, Number(page) || 1), totalPages);
}

function visibleNftRows() {
  const start = (nftsPage - 1) * NFTS_PAGE_SIZE;
  return ownedNftRows.slice(start, start + NFTS_PAGE_SIZE);
}

async function hydrateVisibleNftPage({ loadId, gateway, broadcastNode, force }) {
  const invoke = window.__TAURI__?.core?.invoke;
  if (!invoke || loadId !== nftsLoadId) {
    return;
  }
  const rows = visibleNftRows();
  const loaded = [];
  nftsCachingVisible = false;
  for (const row of rows) {
    if (loadId !== nftsLoadId || currentView !== "nfts") {
      return;
    }
    try {
      if (!force) {
        const cached = await invoke("read_nft_cache", {
          nftName: row.nft_name,
          series: row.series
        });
        if (cached) {
          loaded.push(nftFromCache(row, cached, gateway));
          ownedNfts = loaded.slice();
          renderNftsPage();
          continue;
        }
      }

      nftsCachingVisible = true;
      renderNftsPage();
      const detail = await invoke("nft_details", {
        broadcastNode,
        nftName: row.nft_name,
        series: row.series
      });
      let metadata = null;
      try {
        metadata = await loadNftMetadata(invoke, detail, gateway);
      } catch (error) {
        metadata = { description: `Metadata unavailable: ${String(error)}` };
      }
      const imageUrl = ipfsToGatewayUrl(
        String(metadata?.image || metadata?.image_url || metadata?.animation_url || ""),
        gateway
      );
      let cacheRecord = null;
      try {
        cacheRecord = await invoke("write_nft_cache", {
          nftName: row.nft_name,
          series: row.series,
          detailJson: JSON.stringify(detail),
          metadataJson: JSON.stringify(metadata || {}),
          imageUrl
        });
      } catch (_) {
        cacheRecord = null;
      }

      loaded.push(cacheRecord ? nftFromCache(row, cacheRecord, gateway) : {
        ...row,
        ...detail,
        metadata,
        gateway
      });
      ownedNfts = loaded.slice();
      renderNftsPage();
    } catch (error) {
      loaded.push({
        ...row,
        metadata: { description: `NFT details unavailable: ${String(error)}` },
        gateway
      });
      ownedNfts = loaded.slice();
      renderNftsPage();
    }
  }
  nftsCachingVisible = false;
  ownedNfts = loaded;
  renderNftsPage();
}

async function prepareNftsPage({ force = false } = {}) {
  const invoke = window.__TAURI__?.core?.invoke;
  const broadcastNode = activeBroadcastNode();
  if (!walletLoaded) {
    ownedNfts = [];
    ownedNftRows = [];
    renderNftsPage();
    return;
  }
  if (!invoke || !broadcastNode) {
    ownedNfts = [];
    ownedNftRows = [];
    setNftsState("NFT lookup skipped: wallet bridge or broadcast node is unavailable.");
    renderNftsPage();
    return;
  }
  if (nftsLoading && !force) {
    return;
  }

  const loadId = ++nftsLoadId;
  nftsLoading = true;
  nftsCachingVisible = false;
  renderNftsPage();

  try {
    const [balances, settings, nftRegistry] = await Promise.all([
      invoke("get_active_wallet_balances", { broadcastNode }),
      invoke("read_gui_settings"),
      invoke("nft_list", { broadcastNode })
    ]);
    if (loadId !== nftsLoadId || currentView !== "nfts") {
      return;
    }

    const gateway = normalizeIpfsGateway(settings?.ipfs_gateway);
    ownedNftRows = ownedNftRowsFromBalances(balances, nftRegistry);
    if (!ownedNftRows.length && !Array.isArray(nftRegistry)) {
      ownedNftRows = legacyOwnedNftRowsFromBalances(balances);
    }
    nftsPage = clampNftsPage(nftsPage);
    invoke("prune_nft_cache", {
      keepKeys: ownedNftRows.map(nftCacheKey)
    }).catch(() => {});

    ownedNfts = [];
    renderNftsPage();
    await hydrateVisibleNftPage({ loadId, gateway, broadcastNode, force });
  } catch (error) {
    ownedNfts = [];
    ownedNftRows = [];
    setNftsState(String(error));
  } finally {
    if (loadId === nftsLoadId) {
      nftsLoading = false;
      renderNftsPage();
    }
  }
}

function resetNftsPage() {
  nftsLoadId += 1;
  ownedNfts = [];
  ownedNftRows = [];
  selectedNftKey = "";
  nftsPage = 1;
  nftsLoading = false;
  nftsCachingVisible = false;
  resetNftDetails();
  renderNftsPage();
}

nftsList?.addEventListener("click", (event) => {
  const button = event.target.closest("[data-nft-select]");
  const card = event.target.closest("[data-nft-key]");
  const key = button?.dataset.nftSelect || card?.dataset.nftKey || "";
  if (!key) {
    return;
  }
  selectedNftKey = key;
  renderNftsPage();
});

nftsRefreshButton?.addEventListener("click", () => {
  nftMetadataCache.clear();
  prepareNftsPage({ force: true });
});

function reloadNftPageFromControls(force = false) {
  nftsLoadId += 1;
  nftsLoading = false;
  nftsCachingVisible = false;
  ownedNfts = [];
  selectedNftKey = "";
  prepareNftsPage({ force });
}

document.querySelectorAll("[data-nfts-page]").forEach((button) => {
  button.addEventListener("click", () => {
    const totalPages = Math.max(1, Math.ceil(ownedNftRows.length / NFTS_PAGE_SIZE));
    const action = button.dataset.nftsPage;
    if (action === "first") {
      nftsPage = 1;
    } else if (action === "previous") {
      nftsPage = clampNftsPage(nftsPage - 1);
    } else if (action === "next") {
      nftsPage = clampNftsPage(nftsPage + 1);
    } else if (action === "last") {
      nftsPage = totalPages;
    }
    reloadNftPageFromControls();
  });
});

nftsPageInput?.addEventListener("change", () => {
  nftsPage = clampNftsPage(nftsPageInput.value);
  reloadNftPageFromControls();
});