// momme.world browser runtime. Content comes from commands.json — generated
// by build/build.mjs from commands/*.md; edit those files, not this one.
// This file only implements the loop, the typewriter and command dispatch.

let COMMANDS = [];
let INDEX = new Map();

const load = async () => {
  const res = await fetch("/commands.json", { cache: "no-store" });
  const data = await res.json();
  COMMANDS = data.commands;
  INDEX = new Map(COMMANDS.map((c) => [c.name, c]));
};

// ---------- content helpers ----------
const visible = () => COMMANDS.filter((c) => !c.hidden);
const unique = () => COMMANDS.filter((c, i) => COMMANDS.findIndex((x) => x.name === c.name) === i);
const commandNames = () => unique().map((c) => c.name);
const usages = () =>
  visible().filter((c) => c.help).map((c) => `  ${c.name.padEnd(22)} ${c.help}`);
const fail = (message, ...more) => ({ error: message, more: more.filter(Boolean) });
const split = (value) => String(value).split("\n");

const ALIASES = {
  whois: "whoami", about: "whoami", openme: "whoami",
  tech: "stack", tools: "stack",
  links: "social", socials: "social",
  mail: "contact", email: "contact",
  repos: "project", projects: "project", rm: "sudo",
};

// ${...} placeholders a command body may contain; resolved at run time.
const substitutions = (arg) => ({
  args: arg,
  date: () => new Date().toDateString(),
  time: () => new Date().toLocaleTimeString("de-DE"),
  help: () => ["usage: <command>", "", ...usages()].join("\n"),
  ls: () =>
    commandNames()
      .filter((n) => n.includes(" "))
      .map((n) => n.split(" ").slice(1).join(" "))
      .join("  "),
});

const resolve = (body, arg) =>
  String(body).replace(/\$\{(\w+)\}/g, (_, key) => {
    const sub = substitutions(arg)[key];
    return sub === undefined ? "" : typeof sub === "function" ? sub() : sub;
  });

// ---------- dom ----------
const out = document.getElementById("out");
const screen = document.getElementById("screen");
const form = document.getElementById("prompt");
const input = document.getElementById("cmd");

const make = (tag, cls, value) => {
  const node = document.createElement(tag);
  if (cls) node.className = cls;
  if (value != null) node.textContent = value;
  return node;
};

const scrollDown = () => (screen.scrollTop = screen.scrollHeight);

// ---------- typewriter ----------
// print() never renders directly: it queues fully-built line nodes and this
// machine writes them character by character. A keypress or click while
// typing is active dumps the pending output instantly; `clear` drops it.
const TYPE_MS = matchMedia("(prefers-reduced-motion: reduce)").matches ? 0 : 5;
let queue = [];
let typing = null;
let fast = false;
let gen = 0;
let dumpNow = null;

// finish the line being typed synchronously; the queue then drains instantly
const flatten = (node) =>
  node.segs.forEach((seg) => node.append(seg.href ? anchor(seg) : seg.text));

const flush = () => {
  if (!typing && !queue.length) return;
  fast = true;
  if (dumpNow) dumpNow();
  else if (typing) write();
  else pump();
};

const kill = () => {
  gen++;
  queue.length = 0;
  typing = null;
  dumpNow = null;
  fast = false;
};

function print(value, arg) {
  const lines = [];
  if (value && value.error) {
    lines.push(build(value.error, "text-[#ff7b72]"));
    value.more.forEach((line) => lines.push(build(line, "text-[#5c6f8a]")));
  } else {
    split(resolve(value, arg)).forEach((line) => lines.push(build(line, "")));
  }
  queue.push(lines);
  pump();
}

// Split a line into typed fragments: plain text, or a link that lands whole.
const LINK = /(https?:\/\/\S+|mailto:\S+)/;

function build(line, cls) {
  const node = make("span", "block min-h-[1.35em] " + (cls || ""));
  const segs = [];
  if (!LINK.test(line)) {
    segs.push({ text: line || "\u200b" });
  } else {
    const arrow = line.indexOf("->");
    if (arrow > 0) segs.push({ text: line.slice(0, arrow) });
    (arrow > 0 ? line.slice(arrow + 2) : line).split(LINK).forEach((part) => {
      if (!part) return;
      if (!LINK.test(part)) return segs.push({ text: part });
      segs.push({ href: part, text: part });
    });
  }
  node.segs = segs;
  return node;
}

const anchor = (seg) => {
  const a = make("a", "text-accent hover:underline", seg.text);
  a.href = seg.href;
  if (!seg.href.startsWith("mailto:")) a.rel = "noopener me";
  return a;
};

function pump() {
  if (typing || !queue.length) return;
  typing = { g: gen, lines: queue.shift(), i: 0 };
  write();
}

function write() {
  if (!typing) return;
  if (typing.i >= typing.lines.length) {
    typing = null;
    if (!queue.length) fast = false;
    scrollDown();
    return pump();
  }
  const node = typing.lines[typing.i];
  out.append(node);
  if (fast) {
    flatten(node);
    typing.i++;
    scrollDown();
    return write();
  }
  const g = typing.g;
  typeSegs(node, g, () => {
    if (typing && typing.g === g) typing.i++;
    write();
  });
}

function typeSegs(node, g, ready) {
  const segs = node.segs;
  if (!TYPE_MS) return dump(segs, null);
  const caret = make("span", "cursor");
  let si = 0, ci = 0, tn = null;
  node.append(caret);
  dumpNow = () => { dumpNow = null; dump(segs, caret); };

  (function tick() {
    if (g !== gen) return;
    if (fast) return dump(segs, caret);
    if (si >= segs.length) return dump(segs, caret);
    const seg = segs[si];
    if (seg.href) {
      node.insertBefore(anchor(seg), caret);
      si++;
      return setTimeout(tick, TYPE_MS * 6);
    }
    if (!tn) {
      tn = document.createTextNode("");
      node.insertBefore(tn, caret);
    }
    if (ci < seg.text.length) {
      tn.appendData(seg.text[ci++]);
      if (ci % 8 === 0) scrollDown();
      return setTimeout(tick, TYPE_MS);
    }
    si++, (ci = 0), (tn = null);
    tick();
  })();

  function dump(segs, caret) {
    dumpNow = null;
    if (tn) {
      const seg = segs[si];
      if (seg && !seg.href) tn.appendData(seg.text.slice(ci));
      si++, (ci = 0);
    }
    caret && caret.remove();
    for (; si < segs.length; si++) {
      const seg = segs[si];
      seg.href ? node.append(anchor(seg)) : node.append(seg.text);
    }
    scrollDown();
    ready();
  }
}

// ---------- the loop ----------
const history = { items: [], at: 0 };

function recall(step) {
  history.at += step;
  if (history.at < 0) history.at = 0;
  if (history.at >= history.items.length) {
    history.at = history.items.length;
    input.value = "";
    return;
  }
  input.value = history.items[history.at];
}

// Resolve input words to [command, argument]. Longest multi-word name wins so
// "project fpv" beats any one-word command; a command with params swallows
// the rest.
function lookup(words) {
  for (let len = words.length; len > 0; len--) {
    const joined = words.slice(0, len).join(" ");
    const cmd = INDEX.get(ALIASES[joined] || joined);
    if (cmd) return [cmd, words.slice(len).join(" ")];
  }
  return [null, ""];
}

function execute(raw) {
  flush();
  out.append(make("div", "block text-fg mt-4", raw));
  const words = raw.trim().toLowerCase().split(/\s+/).filter(Boolean);
  if (!words.length) return scrollDown();
  if (words[0] === "clear") return kill(), (out.textContent = "");

  const [cmd, arg] = lookup(words);
  if (!cmd) {
    const near = commandNames().filter((n) => n !== words[0] && n.startsWith(words[0])).slice(0, 3);
    return print(fail(`command not found: ${words[0]}`,
      near.length ? `did you mean: ${near.join(", ")}` : "see: help"), "");
  }

  // argument on a parent: either a known subcommand or a name error
  if (arg && !cmd.params && !cmd.prefix) {
    const kids = commandNames().filter((n) => n.startsWith(cmd.name + " "));
    if (kids.length) {
      const kid = INDEX.get(cmd.name + " " + arg);
      if (kid) return print(resolve(kid.body, ""), "");
      return print(fail(`no ${cmd.name} called "${arg}"`,
        "names: " + kids.map((k) => k.slice(cmd.name.length + 1)).join(", ")), "");
    }
  }
  return print(resolve(cmd.body, arg), arg);
}

form.addEventListener("submit", (event) => {
  event.preventDefault();
  const raw = input.value;
  input.value = "";
  if (raw.trim()) history.items.push(raw.trim());
  history.at = history.items.length;
  execute(raw);
});

input.addEventListener("keydown", (event) => {
  flush();
  if (event.key === "ArrowUp") { event.preventDefault(); recall(-1); }
  if (event.key === "ArrowDown") { event.preventDefault(); recall(1); }
  if (event.key !== "Tab") return;
  const word = input.value.trim().toLowerCase().split(/\s+/)[0];
  const hit = commandNames().filter((n) => word && n.startsWith(word));
  if (hit.length === 1) { event.preventDefault(); input.value = hit[0] + " "; }
});

screen.addEventListener("click", () => {
  flush();
  if (!getSelection().toString()) input.focus();
});

load().then(
  () => {
    document.querySelectorAll("[data-run]").forEach((button) =>
      button.addEventListener("click", () => {
        execute(button.dataset.run);
        input.focus();
      })
    );
    print("hello — type help for the rest of it.", "");
    input.focus();
  },
  () => print({ error: "commands.json did not load — did the site generator run?", more: [] }, "")
);