#!/usr/bin/env -S node --experimental-strip-types
/**
 * The lab's two callers want different things from the same verbs: a coordinator wants
 * structured results and clean teardown, a person wants readable output and the failing
 * scenario left standing. Both use these verbs; the difference is what happens after.
 */

import { loadScenario } from "./declaration/parse.ts";
import { DeclarationError } from "./declaration/validate.ts";
import { isReachable, supportedDrivers, pools } from "./incus/client.ts";
import { raise, RaiseError } from "./lifecycle/raise.ts";
import { assertSupported, UnsupportedError } from "./lifecycle/supported.ts";
import { diagramFromDeclaration } from "./diagram/from-declaration.ts";
import { diagramFromLive } from "./diagram/from-live.ts";
import { toDrawio } from "./diagram/drawio.ts";
import { writeFileSync } from "node:fs";
import { destroy, exec, list, restore, snapshot, snapshots } from "./lifecycle/operate.ts";

const USAGE = `mesh-lab — raise a disposable mesh on one machine

  check                          verify this machine can run scenarios
  validate <scenario.yml>        parse and check a declaration, raising nothing
  raise <scenario.yml>           materialise it, and wait until the machines are usable
  list                           scenario instances currently standing
  exec <instance> <machine> -- <cmd...>
  snapshot <instance> <label>    capture the whole scenario as one state
  restore <instance> <label>     return the whole scenario to it
  snapshots <instance>
  destroy <instance>
  diagram <scenario.yml> [out.drawio]      draw what a scenario asks for
  diagram --live <instance> [out.drawio]   draw what is actually raised

  warm                           the scenario kept between runs, and whether it still counts
  warm cool                      destroy it and forget it
  suite [paths...] [--no-build]  rebuild the artifacts, run the end-to-end tests, leave a receipt
  last-run                       whether the last run still counts; non-zero when it does not

  connect [instance]             reach the standing scenario from this workstation, by name
  disconnect                     give the address back and stop answering those names
  connected                      what is reachable right now

A scenario is a closed address space, so only one can be reachable at a time: connect refuses
rather than guessing which you meant. It needs root for an address and a resolver rule, and
disconnect puts both back.

Set MESH_LAB_INCUS if the daemon needs a different invocation, e.g. "sudo -n incus".
`;

function fail(message: string): never {
  console.error(message);
  process.exit(1);
}

/**
 * Refuse to run degraded rather than warning. A warning about a slow inner loop is read
 * once and ignored forever, and the loop stays slow.
 */
async function check(): Promise<void> {
  const problems: string[] = [];

  if (!(await isReachable())) {
    problems.push(
      "the incus daemon is not reachable as this user. If the group was granted recently, " +
        "a session that predates it cannot see it — log out and back in, or set MESH_LAB_INCUS.",
    );
    console.error(problems.map((p) => `  ✗ ${p}`).join("\n"));
    process.exit(1);
  }
  console.log("  ✓ daemon reachable");

  const drivers = await supportedDrivers();
  const cowDrivers = drivers.filter((d) => d === "btrfs" || d === "zfs");
  if (cowDrivers.length === 0) {
    problems.push(
      "no copy-on-write storage driver is offered. Snapshots would be full copies — " +
        "measured at roughly 76x slower, which does not make the lab slow, it makes it unused.",
    );
  } else {
    console.log(`  ✓ copy-on-write driver available (${cowDrivers.join(", ")})`);
  }

  const available = await pools();
  const cowPool = available.find((p) => p.driver === "btrfs" || p.driver === "zfs");
  if (!cowPool) {
    problems.push(
      `no pool uses a copy-on-write driver (have: ${available.map((p) => `${p.name}/${p.driver}`).join(", ") || "none"}). ` +
        "A pool that exists and is the slow kind is the failure with no symptom.",
    );
  } else {
    console.log(`  ✓ copy-on-write pool '${cowPool.name}' (${cowPool.driver})`);
  }

  if (problems.length > 0) {
    console.error(`\n${problems.map((p) => `  ✗ ${p}`).join("\n\n")}`);
    process.exit(1);
  }
  console.log("\nthis machine can run scenarios");
}

async function main(): Promise<void> {
  const [verb, ...rest] = process.argv.slice(2);

  switch (verb) {
    case "check":
      return check();

    // Rebuilding, running, and recording that it ran are one act. Separate commands would mean a
    // run against a stale artifact, or a run nobody recorded — and both are the state
    // novox/hq 04-ISSUES/005 is about.
    case "suite": {
      const { runSuite } = await import("./suite.ts");
      process.exitCode = await runSuite(rest);
      return;
    }

    // **What 04-ISSUES/005 says nobody was ever told.** The suite needs a machine with a
    // hypervisor, so it cannot run on every push — which means it runs when somebody remembers,
    // and remembering is not a mechanism. This asks whether the last run still means anything,
    // and exits non-zero when it does not, so a timer or a person can act on it.
    case "last-run": {
      const { read, judge, whatWasTested } = await import("./lastrun.ts");
      const said = judge(read(), new Date(), whatWasTested());
      for (const line of said.lines) console.log(line);
      if (!said.current) {
        console.log("\n  `npm run check` runs it.");
        process.exitCode = 1;
      }
      return;
    }

    // A base state many tests start from, rather than each raising its own mesh.
    //
    // **The speed is the lesser half.** Tests that share one long-lived mesh accumulate each
    // other's state, and a test that reads what the previous one left is a test that passes for
    // the wrong reason — which has already happened here once. Returning to a named state between
    // tests makes each of them independent.
    case "warm": {
      const { remembered, ready, cool } = await import("./warm.ts");
      const what = rest[0] ?? "status";
      if (what === "cool") {
        const gone = await cool();
        console.log(gone ? `destroyed ${gone}, and forgot it` : "nothing was being kept warm");
        return;
      }
      const held = remembered();
      if (!held) {
        console.log("nothing is being kept warm.");
        console.log("  a scenario is warmed by whatever brought it to a state worth keeping;");
        console.log("  the integration suite does it when MESH_LAB_WARM is set.");
        return;
      }
      console.log(`${held.instanceId} — ${held.scenario}, warmed ${held.at}`);
      for (const [name, commit] of Object.entries(held.against)) {
        console.log(`  ${name.padEnd(14)} ${commit}`);
      }
      const said = await ready(held.scenario);
      console.log(said.use === "restore"
        ? "\n  usable: it can be returned to"
        : `\n  NOT usable: ${said.why}`);
      if (said.use !== "restore") process.exitCode = 1;
      return;
    }

    case "base": {
      // `base build` exists because a sealed scenario cannot install a container runtime, and
      // the runtime has to come from somewhere with a network (novox/hq ADR 0006).
      if (rest[0] !== "build") fail("base needs a subcommand: build");
      const { buildBaseImage } = await import("./lifecycle/base.ts");
      const built = await buildBaseImage((line) => console.log(line));
      console.log(`${built.alias}: built, with docker ${built.runtime}`);
      return;
    }

    case "validate": {
      const path = rest[0] ?? fail("validate needs a scenario file");
      const scenario = loadScenario(path);
      console.log(
        `${scenario.scenario}: ${Object.keys(scenario.segments).length} segments, ` +
          `${Object.keys(scenario.machines).length} machines — valid`,
      );
      // Valid and raisable are different questions, and a scenario can be the first
      // without being the second.
      try {
        assertSupported(scenario);
      } catch (err) {
        if (err instanceof UnsupportedError) {
          console.log(`\nnot yet raisable:\n  - ${err.missing.join("\n  - ")}`);
        } else throw err;
      }
      return;
    }

    case "connect": {
      const { connect } = await import("./lifecycle/connect.ts");
      const reached = await connect(rest[0]);
      console.log(`connected to ${reached.instanceId} as ${reached.address} on ${reached.bridge}\n`);
      console.log("these answer here now:");
      for (const [machine, address] of Object.entries(reached.machines).sort()) {
        console.log(`  anything.${machine}.internal  →  ${address}`);
      }
      console.log(`\ntry:  curl -sI http://${Object.keys(reached.machines)[0]}.internal`);
      console.log("run `mesh-lab disconnect` when finished — these names are only true while");
      console.log("that scenario is standing.");
      return;
    }

    case "disconnect": {
      const { disconnect } = await import("./lifecycle/connect.ts");
      for (const line of await disconnect()) console.log(line);
      return;
    }

    case "connected": {
      const { connection } = await import("./lifecycle/connect.ts");
      const now = await connection();
      if (now.length === 0) {
        console.log("nothing is connected");
        process.exitCode = 1;
        return;
      }
      for (const line of now) console.log(`  ${line}`);
      return;
    }

    case "raise": {
      const path = rest[0] ?? fail("raise needs a scenario file");
      const scenario = loadScenario(path);
      const started = Date.now();
      const raised = await raise(scenario, {
        onProgress: (m) => console.log(m),
        ...(process.env["MESH_LAB_IMAGE"] ? { image: process.env["MESH_LAB_IMAGE"] } : {}),
      });
      const seconds = ((Date.now() - started) / 1000).toFixed(1);
      console.log(`\nraised ${raised.instanceId} in ${seconds}s — ${raised.machines.length} machines usable`);
      if (raised.images.length > 0) {
        // Printed because this is what a declaration pins, and it is not knowable until the
        // scenario has been raised — the digest belongs to this registry.
        console.log(`\nimages served, pinned by digest:`);
        for (const image of raised.images) console.log(`  ${image}`);
      }
      if (scenario.snapshot) {
        const took = await snapshot(raised.instanceId, scenario.snapshot);
        console.log(`snapshot '${scenario.snapshot}' in ${took.toFixed(2)}s`);
      }
      return;
    }

    case "list": {
      const found = await list();
      if (found.length === 0) return console.log("no scenario instances standing");
      for (const instance of found) {
        console.log(`${instance.instanceId}`);
        for (const m of instance.machines) console.log(`  ${m.machine.padEnd(16)} ${m.status}`);
      }
      return;
    }

    case "exec": {
      const [instanceId, machine, ...command] = rest;
      if (!instanceId || !machine || command.length === 0) fail("exec <instance> <machine> <cmd...>");
      const result = await exec(instanceId, machine, command.filter((c) => c !== "--"));
      process.stdout.write(result.stdout);
      process.stderr.write(result.stderr);
      return;
    }

    case "snapshot": {
      const [instanceId, label] = rest;
      if (!instanceId || !label) fail("snapshot <instance> <label>");
      const took = await snapshot(instanceId, label);
      console.log(`snapshot '${label}' in ${took.toFixed(2)}s`);
      return;
    }

    case "restore": {
      const [instanceId, label] = rest;
      if (!instanceId || !label) fail("restore <instance> <label>");
      const { restoreSeconds, usableSeconds } = await restore(instanceId, label, 180, (m) =>
        console.log(m),
      );
      console.log(
        `restored '${label}' in ${restoreSeconds.toFixed(2)}s — usable again after ` +
          `${usableSeconds.toFixed(1)}s`,
      );
      return;
    }

    case "snapshots": {
      const instanceId = rest[0] ?? fail("snapshots <instance>");
      const found = await snapshots(instanceId);
      console.log(found.length ? found.join("\n") : "none");
      return;
    }

    case "diagram": {
      const live = rest[0] === "--live";
      const target = (live ? rest[1] : rest[0]) ?? fail("diagram needs a scenario file or --live <instance>");
      const diagram = live
        ? await diagramFromLive(target)
        : diagramFromDeclaration(loadScenario(target));
      const out = (live ? rest[2] : rest[1]) ?? `${diagram.title}.drawio`;
      writeFileSync(out, toDrawio(diagram));
      console.log(
        `${out} — ${diagram.segments.length} segments, ${diagram.machines.length} machines ` +
          `(${diagram.source})`,
      );
      return;
    }

    case "destroy": {
      const instanceId = rest[0] ?? fail("destroy <instance>");
      const { machines, networks } = await destroy(instanceId);
      console.log(`destroyed ${instanceId} — ${machines} machines, ${networks} segments`);
      return;
    }

    default:
      console.log(USAGE);
      process.exit(verb ? 1 : 0);
  }
}

main().catch((err: unknown) => {
  if (err instanceof DeclarationError || err instanceof RaiseError) fail(err.message);
  if (err instanceof UnsupportedError) fail(err.message);
  fail(err instanceof Error ? err.message : String(err));
});