 block
   *   {pause: ms}     -> delay
   *   {dim: text}     -> typed dim line
   */
  async function typeLines(items, opts) {
    const o = opts || {};
    const charDelay = o.charDelay != null ? o.charDelay : 3;
    const lineDelay = o.lineDelay != null ? o.lineDelay : 20;
    for (const item of items) {
      if (typeof item === "string") {
        await typeLine(item, null, charDelay);
      } else if (item.dim != null) {
        await typeLine(item.dim, "dim", charDelay);
      } else if (item.html != null) {
        addHtml(item.html);
      } else if (item.pre != null) {
        addPre(item.pre, item.cls);
      } else if (item.pause != null) {
        if (!REDUCED) await sleep(item.pause);
      }
      if (!REDUCED) await sleep(lineDelay);
    }
  }

  /* ---------------- Content ---------------- */
  const BANNER = [
    "  ____   _   _     _     _   _  _____  ___ ",
    " / ___| | | | |   / \\   | \\ | ||_   _||_ _|",
    " \\___ \\ | |_| |  / _ \\  |  \\| |  | |   | | ",
    "  ___) ||  _  | / ___ \\ | |\\  |  | |   | | ",
    " |____/ |_| |_|/_/   \\_\\|_| \\_|  |_|  |___|  .sh"
  ].join("\n");

  const FILES = {
    "about.txt": [
      "Shanti — AI Automation Studio (ShantiLink).",
      "",
      "I design n8n workflow automation, AI assistants,",
      "and integrations: LINE OA, Facebook Ads, Google",
      "Sheets, OpenAI, Airtable, Notion, Telegram.",
      "",
      "More: shantilink.com"
    ].join("\n"),
    "contact.vcf": [
      "BEGIN:VCARD",
      "VERSION:2.1",
      "FN:Shanti",
      "TITLE:AI Automation Consultant",
      "URL:https://shantilink.com",
      "X-FASTWORK:https://fastwork.co/user/shanti/ai-consultant-57814703",
      "END:VCARD"
    ].join("\n")
  };

  /* ---------------- Commands ---------------- */
  const COMMANDS = {
    help: {
      desc: "about + commands",
      run: async () => {
        await typeLines([
          { pre: [
            "SHANTILINK — AI AUTOMATION STUDIO",
            "==========================================",
            "Shanti · AI consultant & automation builder",
            "",
            "I build n8n workflow automation, AI assistants,",
            "and integrations that run businesses on autopilot:",
            "LINE OA · Facebook Ads · Google Sheets · OpenAI ·",
            "Airtable · Notion · Telegram.",
            "",
            "SERVICES",
            "  · workshop    online AI / automation training",
            "  · build       custom n8n automation systems",
            "  · consult     AI strategy & integration"
          ].join("\n") },
          { pre: [
            "",
            "COMMANDS",
            "------------------------------------------",
            "  info / help     this screen",
            "  projects        my work        → /project",
            "  skills          my stack       → /skills",
            "  courses         my lessons     → /courses",
            "  contact         get in touch   → shantilink.com",
            "  ls              list files",
            "  cat       read a file",
            "  theme    green | amber | white",
            "  clear           clear the screen",
            "  exit            power down the terminal"
          ].join("\n") },
          { dim: "tip: Tab completes, arrows recall history." }
        ]);
      }
    },

    info: {
      desc: "about + commands",
      run: async () => { await COMMANDS.help.run(); }
    },

    whoami: {
      desc: "who is shanti?",
      run: async () => {
        await typeLines([
          "Shanti — AI automation consultant.",
          "I build n8n workflows, AI assistants, and",
          "integrations that run businesses on autopilot.",
          { dim: "(see also: projects, skills, contact)" }
        ], { charDelay: 8 });
      }
    },

    projects: {
      desc: "my work → /project",
      run: async () => {
        await typeLines([
          "Opening project archive…",
          { dim: "→ /project" }
        ], { charDelay: 8 });
        await sleep(650);
        window.location.href = "/project";
      }
    },

    skills: {
      desc: "my stack → /skills",
      run: async () => {
        await typeLines([
          "Loading capability matrix…",
          { dim: "→ /skills" }
        ], { charDelay: 8 });
        await sleep(650);
        window.location.href = "/skills";
      }
    },

    courses: {
      desc: "my lessons → /courses",
      run: async () => {
        await typeLines([
          "Opening course catalog…",
          { dim: "→ /courses" }
        ], { charDelay: 8 });
        await sleep(650);
        window.location.href = "/courses";
      }
    },

    contact: {
      desc: "get in touch",
      run: async () => {
        await typeLines([
          "Reaching Shanti…  carrier acquired.",
          { html: 'home    shantilink.com' },
          { html: 'hire    Fastwork' },
          { html: 'line    chat on LINE' },
          { html: 'fb      facebook.com/shantilink' },
          { html: 'docs    docs.shantilink.com' },
          { dim: "primary: shantilink.com" }
        ], { charDelay: 8 });
      }
    },

    ls: {
      desc: "list files",
      run: async () => {
        await typeLines([
          { pre: [
            "total 4",
            "-rw-r--r--  1 shanti  users   312 Jun  1  1978 about.txt",
            "drwxr-xr-x  4 shanti  users   128 Jun  1  1978 projects/",
            "-rw-r--r--  1 shanti  users   142 Jun  1  1978 contact.vcf",
            "-rw-------  1 shanti  users  1978 Jun  1  1978 .secrets"
          ].join("\n") }
        ]);
      }
    },

    cat: {
      desc: "read a file",
      run: async (args) => {
        const f = args[0];
        if (!f) {
          await typeLines([{ dim: "usage: cat " }]);
        } else if (f === ".secrets") {
          await typeLines([
            "cat: .secrets: Permission denied",
            { dim: "nice try. the real secret is `theme amber`." }
          ]);
        } else if (f === "projects" || f === "projects/") {
          await typeLines(["cat: projects/: Is a directory", { dim: "try the `projects` command instead." }]);
        } else if (FILES[f]) {
          await typeLines([{ pre: FILES[f] }]);
        } else {
          await typeLines(["cat: " + f + ": No such file or directory"]);
        }
      }
    },

    theme: {
      desc: "green | amber | white",
      run: async (args) => {
        const name = (args[0] || "").toLowerCase();
        if (!THEMES[name]) {
          await typeLines([
            "usage: theme ",
            { dim: "current phosphor: " + currentTheme }
          ]);
          return;
        }
        if (!REDUCED) {
          crt.classList.remove("theme-flick");
          void crt.offsetWidth; /* restart animation */
          crt.classList.add("theme-flick");
        }
        document.documentElement.style.setProperty("--phos", THEMES[name]);
        currentTheme = name;
        await typeLines(["phosphor recalibrated: " + name.toUpperCase()]);
      }
    },

    clear: {
      desc: "clear the screen",
      run: async () => { out.innerHTML = ""; }
    },

    sudo: {
      desc: "",
      hidden: true,
      run: async () => {
        await typeLines([
          "visitor is not in the sudoers file.",
          "This incident will be reported… to no one."
        ], { charDelay: 8 });
      }
    },

    exit: {
      desc: "power down the terminal",
      run: async () => {
        await typeLines([{ dim: "logout" }, { pause: 350 }]);
        powerOff();
      }
    }
  };

  let currentTheme = "green";

  /* ---------------- Shell mechanics ---------------- */
  function renderTyped() {
    typedEl.textContent = buffer;
    scrollBottom();
  }

  function showPrompt(show) {
    promptLine.classList.toggle("active", show);
    if (show) scrollBottom();
  }

  function echoInput(text) {
    addHtml('' + esc(PROMPT) + "" + esc(text));
  }

  async function execute(raw) {
    const input = raw.trim();
    busy = true;
    hurry = false;
    showPrompt(false);
    echoInput(raw);

    if (input) {
      history.push(input);
      histIdx = history.length;

      const parts = input.split(/\s+/);
      const name  = parts[0].toLowerCase();
      const args  = parts.slice(1);
      const cmd   = COMMANDS[name];

      try {
        if (cmd) {
          await cmd.run(args);
        } else {
          await typeLines(["sh: command not found: " + name + " — try 'help'"]);
        }
      } catch (e) {
        await typeLines([{ dim: "sh: internal fault: " + e.message }]);
      }
    }

    busy = false;
    hurry = false;
    if (state === "shell") {
      buffer = "";
      renderTyped();
      showPrompt(true);
    }
  }

  function tabComplete() {
    const parts = buffer.split(/\s+/);
    if (parts.length <= 1) {
      const frag = parts[0] || "";
      const names = Object.keys(COMMANDS).filter(n => !COMMANDS[n].hidden || frag);
      const matches = names.filter(n => n.startsWith(frag) && frag.length > 0);
      if (matches.length === 1) {
        buffer = matches[0] + " ";
        renderTyped();
      } else if (matches.length > 1) {
        echoInput(buffer);
        addHtml('' + esc(matches.join("  ")) + "", "dim");
      }
    } else if (parts[0].toLowerCase() === "cat") {
      const frag = parts[parts.length - 1];
      const files = Object.keys(FILES).concat([".secrets", "projects/"]);
      const matches = files.filter(f => f.startsWith(frag));
      if (matches.length === 1) {
        parts[parts.length - 1] = matches[0];
        buffer = parts.join(" ");
        renderTyped();
      } else if (matches.length > 1) {
        echoInput(buffer);
        addHtml('' + esc(matches.join("  ")) + "", "dim");
      }
    }
  }

  function insertText(text) {
    buffer += text;
    renderTyped();
  }

  /* ---------------- Keyboard handling ---------------- */
  const FKEY_MAP = { F1: "help", F2: "projects", F3: "skills", F4: "contact", F5: "courses" };

  document.addEventListener("keydown", (e) => {
    if (state === "off") {
      if (e.key === "Enter") reboot();
      return;
    }

    /* any key during output = fast-forward */
    if (busy || state === "boot") {
      hurry = true;
      if (e.key.length === 1 || e.key === "Backspace" || e.key === "Enter" || e.key === "Tab") {
        e.preventDefault();
      }
      return;
    }
    if (state !== "shell") return;

    if (FKEY_MAP[e.key]) {
      e.preventDefault();
      runChip(FKEY_MAP[e.key]);
      return;
    }

    if (e.ctrlKey && !e.altKey && !e.metaKey) {
      const k = e.key.toLowerCase();
      if (k === "c") {
        e.preventDefault();
        echoInput(buffer + "^C");
        buffer = "";
        renderTyped();
        return;
      }
      if (k === "l") {
        e.preventDefault();
        out.innerHTML = "";
        scrollBottom();
        return;
      }
      return; /* let other ctrl shortcuts through */
    }
    if (e.metaKey || e.altKey) return;

    switch (e.key) {
      case "Enter":
        e.preventDefault();
        execute(buffer);
        break;
      case "Backspace":
        e.preventDefault();
        buffer = buffer.slice(0, -1);
        renderTyped();
        break;
      case "Tab":
        e.preventDefault();
        tabComplete();
        break;
      case "ArrowUp":
        e.preventDefault();
        if (history.length) {
          if (histIdx === history.length) savedBuffer = buffer;
          histIdx = Math.max(0, histIdx - 1);
          buffer = history[histIdx] || "";
          renderTyped();
        }
        break;
      case "ArrowDown":
        e.preventDefault();
        if (histIdx < history.length) {
          histIdx = Math.min(history.length, histIdx + 1);
          buffer = histIdx === history.length ? savedBuffer : history[histIdx];
          renderTyped();
        }
        break;
      case "Escape":
        e.preventDefault();
        buffer = "";
        renderTyped();
        break;
      default:
        if (e.key.length === 1) {
          e.preventDefault(); /* stops the hidden input from double-firing */
          insertText(e.key);
        }
    }
  });

  /* Mobile / IME: characters arrive via the hidden input's `input` event
     (desktop printable keys are preventDefault-ed above, so no doubles). */
  kb.addEventListener("input", () => {
    if (state === "shell" && !busy && kb.value) insertText(kb.value);
    kb.value = "";
  });

  /* focus keyboard on tap/click, but never break link clicks or selection */
  document.addEventListener("click", (e) => {
    if (e.target.closest("a, button, .reboot")) return;
    const sel = window.getSelection();
    if (sel && sel.toString().length > 0) return;
    kb.focus({ preventScroll: true });
  });

  /* quick-command chips */
  function runChip(cmd) {
    if (state !== "shell" || busy) return;
    buffer = cmd;
    renderTyped();
    execute(buffer);
  }
  document.getElementById("fkeys").addEventListener("click", (e) => {
    const btn = e.target.closest(".fkey");
    if (btn) runChip(btn.dataset.cmd);
  });

  /* ---------------- Power on / off ---------------- */
  function powerOff() {
    state = "off";
    showPrompt(false);
    crt.classList.remove("crt-on");
    crt.classList.add("crt-off");
    const delay = REDUCED ? 0 : 750;
    setTimeout(() => { lost.classList.add("visible"); }, delay);
  }

  function reboot() {
    lost.classList.remove("visible");
    crt.classList.remove("crt-off");
    out.innerHTML = "";
    buffer = "";
    renderTyped();
    boot();
  }
  document.getElementById("rebootBtn").addEventListener("click", reboot);
  document.getElementById("rebootBtn").addEventListener("keydown", (e) => {
    if (e.key === "Enter" || e.key === " ") { e.preventDefault(); reboot(); }
  });

  /* ---------------- Boot sequence ---------------- */
  async function memoryTest() {
    const div = addLine();
    if (REDUCED) {
      div.textContent = "MEMORY TEST: 64K OK";
      return;
    }
    for (let k = 0; k <= 64; k += 4) {
      div.textContent = "MEMORY TEST: " + k + "K";
      scrollBottom();
      await sleep(38);
    }
    div.textContent = "MEMORY TEST: 64K OK";
    scrollBottom();
  }

  async function boot() {
    state = "boot";
    busy = true;
    hurry = false;

    if (!REDUCED) {
      crt.classList.add("crt-on");
      await sleep(850);
      crt.classList.remove("crt-on");
    }

    await typeLines([
      "SHANTI DATASYSTEMS SH-1978 VIDEO TERMINAL",
      { dim: "ROM BIOS CHECK ............ OK" },
      { dim: "CPU: MOS 6502 @ 1.02 MHz .. OK" }
    ], { charDelay: 6, lineDelay: 90 });

    await memoryTest();
    if (!REDUCED) await sleep(180);

    await typeLines([
      { dim: "PHOSPHOR: P1 GREEN ........ OK" },
      { pause: 260 },
      "LOADING SHANTI.SH v5.0 …"
    ], { charDelay: 6, lineDelay: 90 });

    if (!REDUCED) await sleep(420);
    addPre(BANNER, "banner");
    if (!REDUCED) await sleep(260);

    await typeLines([
      { dim: "─".repeat(34) },
      "Welcome, visitor. This terminal is real — it listens.",
      { html: 'Type help to see what it can do.' }
    ], { charDelay: 8, lineDelay: 60 });

    busy = false;
    hurry = false;
    state = "shell";
    buffer = "";
    renderTyped();
    showPrompt(true);
  }

  /* let the "help" hint link run the command */
  out.addEventListener("click", (e) => {
    const a = e.target.closest("a[data-run]");
    if (a) {
      e.preventDefault();
      runChip(a.dataset.run);
    }
  });

  boot();
})();