// Rules: each chain's rules in order, with their hits; add, edit, move.
import { h, mount, table, modal, errorBox, field, input, select, checkbox, confirmDialog, badge, textarea, toast } from "../ui.js";
import { get, api, change, can } from "../api.js";
import { rerender } from "../app.js";
import { names, matchEditor, describe, hits, counters, listEditor, rowClass, live, fmtBytes, quotas } from "../widgets.js";

const chains = [
  ["input", "Input", "Traffic to the firewall itself."],
  ["forward", "Forward", "Traffic through the firewall, between zones."],
  ["output", "Output", "Traffic from the firewall itself."],
  ["early", "Early", "Before connection tracking: cheap drops of what can never be right."],
];

// The built-ins of each chain, as the ruleset has them (settings).
const builtins = {
  early: [["antispoof", "antispoof", "Impossible sources from external zones dropped"], ["antispoof", "antispoof6", "…and IPv6 ones"]],
  input: [["loopback", "loopback", "Everything on lo accepted"], ["established", "established", "Established and related connections accepted"],
    ["drop_invalid", "invalid", "Invalid packets dropped"], ["icmpv6", "icmpv6", "ICMPv6 errors and echo accepted"],
    ["icmpv6", "icmpv6-nd", "Neighbour discovery accepted"], ["icmpv6", "icmpv6-mld", "MLD from link-local accepted"],
    ["ping_internal", "ping", "Ping from internal zones accepted"], ["dhcpv6_client", "dhcpv6-client", "DHCPv6 replies on external zones accepted"]],
  forward: [["mss_clamp", "mss-clamp", "TCP MSS clamped on external zones"], ["established", "established", "Established and related connections accepted"],
    ["drop_invalid", "invalid", "Invalid packets dropped"], ["icmpv6", "icmpv6", "ICMPv6 errors let through"], ["", "", "Port forwards let through (NAT page)"]],
  output: [],
};

export async function render(el, params, query) {
  const chain = query.get("chain") || "input";
  const [all, settings, cs, qs] = await Promise.all([get("/rules", { chain }), get("/settings"), counters(), quotas()]);
  // As nftables checks them: the rules that count traffic first.
  const rules = [...all.filter(countsTraffic), ...all.filter((r) => !countsTraffic(r))];
  const write = can("config", true);
  const info = chains.find((c) => c[0] === chain) || chains[0];
  const policy = settings[chain + "_policy"];
  const bi = (builtins[chain] || []).filter(([flag]) => flag === "" || settings.builtins[flag]);
  const actionBadge = (r) => badge(r.action + (r.log ? " + log" : ""), { accept: "ok", drop: "err", reject: "warn", log: "" }[r.action]);
  mount(el,
    h("div", { class: "page-head" },
      h("div", { class: "grow" }, h("h1", null, "Rules"), h("div", { class: "muted" }, "Checked top to bottom; the first rule that decides wins. ", info[2])),
      write ? h("div", { class: "actions" }, h("button", { class: "primary", onclick: () => ruleDialog(null, chain) }, "Add rule")) : null),
    h("div", { class: "tabs" }, chains.map(([k, label]) => h("a", { href: "#/rules?chain=" + k, class: k === chain ? "active" : "" }, label))),
    h("div", { class: "panel" },
      bi.length ? h("div", { class: "builtins muted small" }, h("strong", null, "Added by Housecarl first: "),
        bi.map(([, mark, text], i) => [i ? " · " : "", text, mark ? [" (", hits(cs, "b-" + mark), ")"] : ""]), " — ",
        h("a", { href: "#/settings" }, "settings")) : null,
      table([
        { label: "#", render: (r) => r.pending === "deleted" ? "" : String(live(rules).indexOf(r) + 1) },
        { label: "Match", render: (r) => r.raw ? [badge("raw", ""), " ", h("span", { class: "mono small" }, r.raw)]
          : [countsTraffic(r) ? [badge("every packet", "accent"), " "] : null, describe(r), extras(r, qs[r.id])] },
        { label: "Action", render: actionBadge },
        { label: "Hits", render: (r) => hits(cs, "r" + r.id) },
        { label: "Comment", render: (r) => r.comment },
        write ? { label: "", tdClass: "actions-cell", render: (r) => {
          if (r.pending === "deleted") return badge("deleted", "err");
          // Moves stay among the rules of the same kind (counting traffic,
          // or not): nftables checks those first.
          const rs = live(rules).filter((x) => countsTraffic(x) === countsTraffic(r)), i = rs.indexOf(r);
          return [
          h("button", { class: "small reveal", title: "Move up", disabled: i === 0, onclick: () => move(r, { before: rs[i - 1].id }) }, "↑"), " ",
          h("button", { class: "small reveal", title: "Move down", disabled: i === rs.length - 1, onclick: () => move(r, { after: rs[i + 1].id }) }, "↓"), " ",
          h("button", { class: "small reveal", onclick: () => ruleDialog(r, chain) }, "Edit"), " ",
          h("button", { class: "small reveal", onclick: () => toggle(r) }, r.disabled ? "Enable" : "Disable"), " ",
          h("button", { class: "small reveal", onclick: () => del(r) }, "Delete"),
        ];
        } } : null,
      ].filter(Boolean), rules, { empty: "No rules in this chain yet.", rowClass }),
      rules.some(countsTraffic) ? h("div", { class: "muted small" }, "Rules marked “every packet” have a quota or a byte rate: they are checked before established connections are accepted, so they count all of a connection's traffic, not only its first packet. They can drop, reject or log, not accept.") : null,
      h("div", { class: "policy small" }, "Then the policy: ", badge(policy, policy === "drop" ? "err" : "ok"),
        policy === "drop" ? [" — ", hits(cs, "p-" + chain), " packets reached it"] : null)));
}

// countsTraffic: a quota or a byte rate (as model.Rule.CountsTraffic).
function countsTraffic(r) {
  return !r.raw && (!!r.quota || !!(r.limit && ["bytes", "kbytes", "mbytes"].includes(r.limit.unit)));
}

function extras(r, q) {
  const x = [];
  if ((r.ct_state || []).length) x.push("state " + r.ct_state.join(","));
  if ((r.ct_status || []).length) x.push("status " + r.ct_status.join(","));
  if ((r.days || []).length) x.push(r.days.join(","));
  if (r.hour_from) x.push(r.hour_from + "–" + r.hour_to);
  if (r.limit) {
    const l = r.limit;
    x.push((l.over ? "over " : "") + l.rate + (l.unit && l.unit !== "packets" ? " " + l.unit : "") + "/" + l.per +
      (l.per_source ? " per source" : l.per_destination ? " per destination" : ""));
  }
  if (r.conn_limit) x.push("over " + r.conn_limit + " connections");
  const out = x.length ? [h("div", { class: "muted small" }, x.join(" · "))] : [];
  if (r.quota) out.push(quotaLine(r, q));
  return out;
}

// quotaLine shows a quota, and what it used: in total, or per address
// (the busiest, and the rest in a dialog).
function quotaLine(r, q) {
  const qt = r.quota;
  const each = qt.per_source ? " each source" : qt.per_destination ? " each destination" : "";
  const resets = qt.reset === "monthly" ? "monthly on day " + (qt.day || 1) : qt.reset || "by hand";
  let used = null;
  if (q && !qt.per_source && !qt.per_destination) {
    used = [h("strong", null, fmtBytes(q.used)), " of " + fmtBytes(qt.bytes) + " used"];
  } else if (q) {
    const n = (q.addresses || []).length;
    used = [n === 1 ? "1 address" : n + " addresses", n ? [", busiest ", h("strong", null, fmtBytes(q.addresses[0].used))] : null, " ",
      n ? h("button", { class: "small", onclick: () => usageDialog(r, q) }, "Usage…") : null];
  }
  return h("div", { class: "muted small" }, (qt.over ? "quota over " : "quota ") + fmtBytes(qt.bytes) + each + ", resets " + resets,
    used ? [" · ", used] : null,
    q && q.next_reset ? " · next reset " + new Date(q.next_reset).toLocaleString() : null,
    can("config", true) && q && r.pending !== "new" ? [" ", h("button", { class: "small", onclick: () => resetQuota(r) }, "Reset")] : null);
}

async function usageDialog(r, q) {
  await modal("Quota usage of " + (r.comment || "rule #" + r.id), h("div", null,
    h("p", { class: "muted" }, "Each " + (r.quota.per_source ? "source" : "destination") + " has " + fmtBytes(r.quota.bytes) + "."),
    table([
      { label: "Address", render: (a) => h("span", { class: "mono" }, a.address) },
      { label: "Used", render: (a) => fmtBytes(a.used) },
      { label: "", render: (a) => h("div", { class: "usage" }, h("div", { class: "usage-bar" + (a.used >= r.quota.bytes ? " full" : "") }, bar(a.used / r.quota.bytes))) },
    ], q.addresses)), [{ label: "Close", value: null }], { wide: true });
}

function bar(f) {
  const seg = h("div", { class: "seg leased" });
  seg.style.width = Math.min(100, f * 100) + "%";
  return seg;
}

async function resetQuota(r) {
  if (!await confirmDialog("Reset the quota", "Start the quota of " + (r.comment || "rule #" + r.id) + " again now" +
    (r.quota.per_source || r.quota.per_destination ? ", for every address" : "") + "? This is done at once, not staged.", "Reset")) return;
  try { await api("POST", "/rules/" + r.id + "/reset-quota"); toast("Quota reset"); rerender(); } catch (e) { modal("Not reset", errorBox(e)); }
}

async function move(r, where) {
  try { await change("POST", "/rules/" + r.id + "/move", where, { quiet: true }); rerender(); } catch (e) { modal("Not moved", errorBox(e)); }
}

async function toggle(r) {
  try { await change("PATCH", "/rules/" + r.id, { disabled: !r.disabled }); rerender(); } catch (e) { modal("Not changed", errorBox(e)); }
}

async function del(r) {
  if (!await confirmDialog("Delete rule", "Delete " + (r.comment || "this rule") + " (" + (r.raw || describe(r)) + ")?", "Delete", "danger")) return;
  try { await change("DELETE", "/rules/" + r.id); rerender(); } catch (e) { modal("Not deleted", errorBox(e)); }
}

// ruleDialog adds (r null) or edits a rule.
export async function ruleDialog(r, chain) {
  const n = await names();
  r = r || { chain, action: "accept" };
  const ch = select([["input", "input (to the firewall)"], ["forward", "forward (through it)"], ["output", "output (from it)"], ["early", "early (before conntrack)"]], r.chain || chain);
  const match = matchEditor(r, n);
  const action = select([["accept", "accept"], ["drop", "drop"], ["reject", "reject"], ["log", "log only (and go on)"]], r.action);
  const rejectWith = select([["", "with an ICMP error"], ["tcp-reset", "with a TCP reset (TCP rules only)"]], r.reject_with || "");
  const showReject = () => rejectWith.classList.toggle("hidden", action.value !== "reject");
  action.addEventListener("change", showReject);
  showReject();
  const states = listEditor(r.ct_state, { suggestions: ["new", "established", "related", "invalid", "untracked"], placeholder: "new", mono: false, addLabel: "Add state" });
  const statuses = listEditor(r.ct_status, { suggestions: ["dnat", "snat"], placeholder: "dnat", mono: false, addLabel: "Add status" });
  const days = listEditor(r.days, { suggestions: ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"], placeholder: "Monday", mono: false, addLabel: "Add day" });
  const hourFrom = input({ value: r.hour_from || "", placeholder: "08:00", class: "short" });
  const hourTo = input({ value: r.hour_to || "", placeholder: "17:30", class: "short" });
  const l = r.limit || {};
  const rate = input({ value: l.rate || "", placeholder: "10", class: "short", type: "number", min: 1 });
  const unit = select([["", "packets"], ["bytes", "bytes"], ["kbytes", "KB"], ["mbytes", "MB"]], l.unit || "", { class: "inline" });
  const per = select(["second", "minute", "hour", "day"], l.per || "minute", { class: "inline" });
  const burst = input({ value: l.burst || "", placeholder: "burst", class: "short", type: "number", min: 0 });
  const over = checkbox("match beyond the rate (to drop floods, or traffic over a bandwidth)", l.over);
  const keyOf = (x) => x.per_source ? "source" : x.per_destination ? "destination" : "";
  const keys = [["", "for everything the rule matches"], ["source", "for each source address"], ["destination", "for each destination address"]];
  const limitKey = select(keys, keyOf(l), { class: "inline" });
  const qt = r.quota || {};
  const gb = qt.bytes && qt.bytes % (1 << 30) === 0;
  const quotaAmount = input({ value: qt.bytes ? qt.bytes / (gb ? 1 << 30 : 1 << 20) : "", placeholder: "50", class: "short", type: "number", min: 1 });
  const quotaUnit = select([["mb", "MB"], ["gb", "GB"]], gb || !qt.bytes ? "gb" : "mb", { class: "inline" });
  const quotaOver = checkbox("match once it is used up (to drop); otherwise while it lasts (to accept)", qt.over === undefined ? true : qt.over);
  const quotaKey = select(keys, keyOf(qt), { class: "inline" });
  const quotaReset = select([["", "only by hand"], ["daily", "daily, at midnight"], ["weekly", "weekly, on Mondays"], ["monthly", "monthly, on day"]], qt.reset || "", { class: "inline" });
  const quotaDay = input({ value: qt.day || "", placeholder: "1", class: "short", type: "number", min: 1, max: 31 });
  const showDay = () => quotaDay.classList.toggle("hidden", quotaReset.value !== "monthly");
  quotaReset.addEventListener("change", showDay);
  showDay();
  const group4 = input({ value: r.group_v4 || "", placeholder: "32", class: "short", type: "number", min: 1, max: 32 });
  const group6 = input({ value: r.group_v6 || "", placeholder: "64", class: "short", type: "number", min: 1, max: 128 });
  const conn = input({ value: r.conn_limit || "", placeholder: "e.g. 20", class: "short", type: "number", min: 1 });
  const log = checkbox("log matching packets (Log page)", r.log);
  const logPrefix = input({ value: r.log_prefix || "", placeholder: "default: hc CHAIN #ID ACTION:" });
  const raw = textarea(r.raw || "", { rows: 2, class: "mono", placeholder: "ip saddr @admins_v4 tcp dport 22 ct state new accept" });
  const comment = input({ value: r.comment || "" });
  const disabled = checkbox("disabled: keep the rule but don't use it", r.disabled);
  const err = h("div");
  const body = h("div", null,
    h("div", { class: "form-grid" },
      field("Chain", ch),
      ...match.flat(),
      field("Action", h("div", null, action, " ", rejectWith)),
      field("Connection state", states),
      field("Connection status", statuses, "dnat: the connection was port forwarded."),
      field("Days", days),
      field("Hours", h("div", null, hourFrom, " to ", hourTo), "22:00 to 06:00 passes midnight."),
      field("Rate limit", h("div", null, rate, " ", unit, " per ", per, " ", burst, " ", limitKey, over),
        "Empty: no limit. In bytes, it is a bandwidth (KB or MB per second or minute); traffic beyond it is dropped, not queued. The burst is in the same unit."),
      field("Quota", h("div", null, quotaAmount, " ", quotaUnit, " ", quotaKey, " resets ", quotaReset, " ", quotaDay, quotaOver),
        "Empty: none. An allowance of traffic; Housecarl keeps the count across changes and restarts."),
      field("Group addresses", h("div", null, "IPv4 /", group4, " IPv6 /", group6),
        "Per-address limits, connection limits and quotas count addresses by these prefixes. Default: each IPv4 address, IPv6 by /64 (one device has several addresses)."),
      field("Connection limit", conn, "Match a source that already has more than this many connections."),
      field("Log", h("div", null, log, logPrefix)),
      field("Raw nftables", raw, "Instead of all the above: one nftables rule, for what Housecarl can't say. Checked by nftables."),
      field("Comment", comment),
      r.id ? [h("label"), disabled] : null),
    err);
  await modal(r.id ? "Edit rule" : "Add rule", body, [
    { label: "Cancel", value: null },
    { label: "Check", onclick: () => save(true) },
    { label: r.id ? "Save" : "Add rule", kind: "primary", onclick: () => save(false) },
  ], { wide: true, sticky: true });

  async function save(dry) {
    mount(err);
    const v = { chain: ch.value, ...match.value(), action: action.value, reject_with: action.value === "reject" ? rejectWith.value : "",
      ct_state: states.value(), ct_status: statuses.value(), days: days.value(), hour_from: hourFrom.value.trim(), hour_to: hourTo.value.trim(),
      limit: rate.value ? { rate: parseInt(rate.value, 10), unit: unit.value, per: per.value, burst: parseInt(burst.value || "0", 10), over: over.input.checked,
        per_source: limitKey.value === "source", per_destination: limitKey.value === "destination" } : null,
      quota: quotaAmount.value ? { bytes: parseInt(quotaAmount.value, 10) * (quotaUnit.value === "gb" ? 1 << 30 : 1 << 20), over: quotaOver.input.checked,
        per_source: quotaKey.value === "source", per_destination: quotaKey.value === "destination",
        reset: quotaReset.value, day: quotaReset.value === "monthly" ? parseInt(quotaDay.value || "1", 10) : 0 } : null,
      group_v4: parseInt(group4.value || "0", 10), group_v6: parseInt(group6.value || "0", 10),
      conn_limit: parseInt(conn.value || "0", 10), log: log.input.checked, log_prefix: logPrefix.value.trim(), raw: raw.value.trim(), comment: comment.value.trim() };
    if (r.id) v.disabled = disabled.input.checked;
    try {
      await change(r.id ? "PATCH" : "POST", r.id ? "/rules/" + r.id : "/rules", v, { query: dry ? { dry_run: 1 } : undefined });
      if (dry) return false;
      if (v.chain !== chain) location.hash = "#/rules?chain=" + v.chain;
      else rerender();
      return true;
    } catch (e) {
      mount(err, errorBox(e));
      return false;
    }
  }
}