const tg = window.Telegram.WebApp;
tg.ready();
tg.expand();

function walletApp() {
  return {
    // ── State ──────────────────────────────────────────────────────────────
    tab: "dashboard",
    botName: tg.initDataUnsafe?.bot?.username ?? "Wallet",
    toastVisible: false,

    wallet: {
      registered: false,
      locked: true,
      balanceSats: 0,
      sparkAddress: "",
      unlockExpiresAt: null,
      sessionPolicy: null,
    },

    // Setup (first launch, no wallet)
    setup: {
      pin: "",
      confirmPin: "",
      error: "",
      creating: false,
    },

    // Seed reveal
    seed: {
      screen: false,
      loading: false,
      words: [],
      error: "",
      confirmed: false,
    },

    // PIN unlock overlay
    showPinOverlay: false,
    pin: "",
    pinError: "",
    unlocking: false,

    // Send
    send: {
      destination: "",
      amountSats: "",
      description: "",
      detectedType: "",
      sending: false,
      error: "",
      success: "",
    },

    // Receive
    receive: {
      tab: "spark",
      sparkAddress: "",
      lightningInvoice: null,
      onchainAddress: null,
      amountSats: "",
    },

    // History
    history: {
      items: [],
      loading: false,
      limit: 20,
      offset: 0,
    },

    // ── Init ───────────────────────────────────────────────────────────────
    async init() {
      if (!tg.initData) {
        document.body.innerHTML = "<p style='padding:2rem;color:red'>Open this app from Telegram.</p>";
        return;
      }

      // Seed reveal via one-time token (from bot onboarding link)
      const params = new URLSearchParams(window.location.search);
      const seedToken = params.get("seedToken");
      if (seedToken && window.location.hash === "#seed") {
        await this.revealSeed(seedToken);
        return;
      }

      await this.refresh();
    },

    // ── API ────────────────────────────────────────────────────────────────
    async api(method, path, body) {
      const opts = {
        method,
        headers: {
          "Content-Type": "application/json",
          "X-Init-Data": tg.initData,
        },
      };
      if (body) opts.body = JSON.stringify(body);
      const res = await fetch(path, opts);
      const data = await res.json();
      if (!res.ok) throw new Error(data.error ?? "Request failed");
      return data;
    },

    // ── Wallet state ───────────────────────────────────────────────────────
    async refresh() {
      try {
        const data = await this.api("GET", "/api/wallet");

        if (!data.registered) {
          this.tab = "setup";
          return;
        }

        this.wallet = data;
        this.receive.sparkAddress = data.sparkAddress;
        this.$nextTick(() => this.renderQr("qr-spark", data.sparkAddress));
      } catch (e) {
        console.error("refresh:", e.message);
      }
    },

    // ── Setup — create wallet ──────────────────────────────────────────────
    async createWallet() {
      this.setup.error = "";

      if (this.setup.pin.length < 6) {
        this.setup.error = "PIN must be at least 6 characters.";
        return;
      }
      if (this.setup.pin !== this.setup.confirmPin) {
        this.setup.error = "PINs do not match.";
        return;
      }

      this.setup.creating = true;
      try {
        const data = await this.api("POST", "/api/setup", { pin: this.setup.pin });
        this.setup.pin = "";
        this.setup.confirmPin = "";

        // Show seed reveal screen immediately after creation
        this.seed.words = data.words;
        this.seed.screen = true;
        this.seed.confirmed = false;

        // Pre-load wallet state for after seed is dismissed
        this.wallet.registered = true;
        this.wallet.sparkAddress = data.sparkAddress;
        this.receive.sparkAddress = data.sparkAddress;
      } catch (e) {
        this.setup.error = e.message;
      } finally {
        this.setup.creating = false;
      }
    },

    // ── Seed reveal — via one-time URL token (from bot link) ───────────────
    async revealSeed(token) {
      this.seed.screen = true;
      this.seed.loading = true;
      try {
        const data = await this.api("GET", `/api/seed/reveal?token=${encodeURIComponent(token)}`);
        this.seed.words = data.words;
      } catch (e) {
        this.seed.error = e.message || "Link already used or expired.";
      } finally {
        this.seed.loading = false;
      }
    },

    async closeSeedScreen() {
      this.seed.words = [];
      this.seed.screen = false;
      this.seed.confirmed = false;
      history.replaceState(null, "", window.location.pathname);
      await this.refresh();
    },

    // ── Unlock / Lock ──────────────────────────────────────────────────────
    async unlock() {
      if (!this.pin) return;
      this.unlocking = true;
      this.pinError = "";
      try {
        await this.api("POST", "/api/unlock", { pin: this.pin });
        this.showPinOverlay = false;
        this.pin = "";
        await this.refresh();
      } catch (e) {
        this.pinError = e.message;
      } finally {
        this.unlocking = false;
      }
    },

    async lock() {
      await this.api("POST", "/api/lock");
      await this.refresh();
    },

    // ── Send ───────────────────────────────────────────────────────────────
    detectType() {
      const d = this.send.destination.trim().toLowerCase();
      if (!d) { this.send.detectedType = ""; return; }
      if (d.startsWith("lnbc") || d.startsWith("lntb") || d.startsWith("lnurl")) {
        this.send.detectedType = "⚡ Lightning";
      } else if (d.startsWith("spark1") || d.includes("@")) {
        this.send.detectedType = "✳️ Spark";
      } else {
        this.send.detectedType = "₿ On-chain";
      }
    },

    async sendPayment() {
      this.send.error = "";
      this.send.success = "";
      if (!this.send.destination.trim()) { this.send.error = "Enter a destination."; return; }

      this.send.sending = true;
      try {
        const body = {
          destination: this.send.destination.trim(),
          amountSats: this.send.amountSats ? parseInt(this.send.amountSats, 10) : undefined,
          description: this.send.description || undefined,
        };
        const res = await this.api("POST", "/api/send", body);
        this.send.success = `✅ Sent! Fee: ${res.feeSats} sats`;
        this.send.destination = "";
        this.send.amountSats = "";
        this.send.description = "";
        this.send.detectedType = "";
        await this.refresh();
      } catch (e) {
        if (e.message === "wallet_locked") {
          this.showPinOverlay = true;
        } else {
          this.send.error = e.message;
        }
      } finally {
        this.send.sending = false;
      }
    },

    // ── Receive ────────────────────────────────────────────────────────────
    async loadReceive() {
      const params = new URLSearchParams();
      if (this.receive.amountSats) params.set("amount", this.receive.amountSats);
      try {
        const data = await this.api("GET", `/api/receive?${params}`);
        this.receive.sparkAddress = data.sparkAddress;
        this.receive.lightningInvoice = data.lightningInvoice;
        this.receive.onchainAddress = data.onchainAddress;
        this.$nextTick(() => {
          this.renderQr("qr-spark", data.sparkAddress);
          if (data.lightningInvoice) this.renderQr("qr-lightning", data.lightningInvoice);
          if (data.onchainAddress) this.renderQr("qr-onchain", data.onchainAddress);
        });
      } catch (e) {
        console.error("loadReceive:", e.message);
      }
    },

    // ── History ────────────────────────────────────────────────────────────
    async loadHistory() {
      this.history.loading = true;
      this.history.offset = 0;
      try {
        const data = await this.api("GET", `/api/history?limit=${this.history.limit}&offset=0`);
        this.history.items = data.transactions;
      } catch (e) {
        console.error("loadHistory:", e.message);
      } finally {
        this.history.loading = false;
      }
    },

    async loadMore() {
      this.history.offset += this.history.limit;
      try {
        const data = await this.api("GET", `/api/history?limit=${this.history.limit}&offset=${this.history.offset}`);
        this.history.items.push(...data.transactions);
      } catch (e) {
        console.error("loadMore:", e.message);
      }
    },

    // ── QR ─────────────────────────────────────────────────────────────────
    renderQr(canvasId, text) {
      if (!text) return;
      const canvas = document.getElementById(canvasId);
      if (!canvas) return;
      QRCode.toCanvas(canvas, text, { width: 220, margin: 2, color: { dark: "#000", light: "#fff" } });
    },

    // ── Helpers ────────────────────────────────────────────────────────────
    satsToBtc(sats) { return (sats / 1e8).toFixed(8); },

    formatExpiry(iso) {
      if (!iso) return "";
      return new Date(iso).toLocaleTimeString([], { hour: "2-digit", minute: "2-digit" });
    },

    formatDate(iso) {
      if (!iso) return "";
      const d = new Date(iso + "Z");
      return d.toLocaleDateString([], { month: "short", day: "numeric" }) + " " +
             d.toLocaleTimeString([], { hour: "2-digit", minute: "2-digit" });
    },

    txIcon(status) {
      return { done: "✅", failed: "❌", processing: "⏳", expired: "💨", awaiting_unlock: "🔒" }[status] ?? "•";
    },

    async copyText(text) {
      try {
        await navigator.clipboard.writeText(text);
        this.toastVisible = true;
        setTimeout(() => { this.toastVisible = false; }, 1500);
      } catch {
        tg.showAlert("Copy: " + text);
      }
    },
  };
}