chore: import upstream snapshot with attribution

bin/cli/commands/simulate.mjs

@@ -0,0 +1,125 @@
+import { readFileSync } from "node:fs";
+import { apiFetch } from "../api.mjs";
+import { emit } from "../output.mjs";
+import { t } from "../i18n.mjs";
+
+const simulateSchema = [
+  { key: "order", header: "#", width: 4 },
+  { key: "provider", header: "Provider", width: 20 },
+  { key: "model", header: "Model", width: 35 },
+  { key: "probability", header: "Probability", formatter: (v) => `${Math.round(v * 100)}%` },
+  { key: "estimatedCost", header: "Est. Cost", formatter: (v) => (v ? `$${v.toFixed(4)}` : "-") },
+  { key: "healthStatus", header: "Breaker", width: 10 },
+  { key: "quotaAvailable", header: "Quota %", formatter: (v) => `${v}%` },
+];
+
+export function registerSimulate(program) {
+  program
+    .command("simulate [prompt]")
+    .description(t("simulate.description"))
+    .option("--file <path>", t("simulate.file"))
+    .option("-m, --model <id>", t("simulate.model"), "auto")
+    .option("--combo <name>", t("simulate.combo"))
+    .option("--reasoning-effort <level>", t("simulate.reasoning"))
+    .option("--thinking-budget <n>", t("simulate.thinking"), parseInt)
+    .option("--explain", t("simulate.explain"))
+    .action(runSimulateCommand);
+}
+
+export async function runSimulateCommand(promptArg, opts, cmd) {
+  const globalOpts = cmd.optsWithGlobals();
+
+  let promptTokenEstimate = 100;
+  if (opts.file) {
+    try {
+      const raw = readFileSync(opts.file, "utf8");
+      const parsed = JSON.parse(raw);
+      const text = JSON.stringify(parsed);
+      promptTokenEstimate = Math.ceil(text.length / 4);
+    } catch {
+      promptTokenEstimate = 100;
+    }
+  } else if (promptArg) {
+    promptTokenEstimate = Math.ceil(promptArg.length / 4);
+  }
+
+  const [combosRes, healthRes, quotaRes] = await Promise.allSettled([
+    apiFetch("/api/combos", { timeout: globalOpts.timeout }).then((r) => r.json()),
+    apiFetch("/api/monitoring/health", { timeout: globalOpts.timeout }).then((r) => r.json()),
+    apiFetch("/api/usage/quota", { timeout: globalOpts.timeout }).then((r) => r.json()),
+  ]);
+
+  if (combosRes.status === "rejected") {
+    process.stderr.write(t("common.serverOffline") + "\n");
+    process.exit(3);
+  }
+
+  const combos = normalizeCombos(combosRes.value);
+  const health = healthRes.status === "fulfilled" ? healthRes.value : {};
+  const quota = quotaRes.status === "fulfilled" ? quotaRes.value : {};
+
+  const targetCombo = opts.combo
+    ? combos.find((c) => c.id === opts.combo || c.name === opts.combo)
+    : combos.find((c) => c.enabled !== false);
+
+  if (!targetCombo) {
+    process.stderr.write(t("simulate.noCombo") + "\n");
+    process.exit(1);
+  }
+
+  const models = getComboModels(targetCombo, opts.model);
+  const breakers = toArray(health.circuitBreakers ?? health.breakers);
+  const providers = toArray(quota.providers ?? quota.data);
+
+  const simulatedPath = models.map((m, idx) => {
+    const cb = breakers.find((b) => String(b.provider) === m.provider);
+    const q = providers.find((p) => p.provider === m.provider);
+    const inputCost = m.inputCostPer1M ?? 0;
+    const estimatedCost = Math.round((promptTokenEstimate / 1_000_000) * inputCost * 10000) / 10000;
+    return {
+      order: idx + 1,
+      provider: m.provider,
+      model: m.model || opts.model,
+      probability: idx === 0 ? 0.85 : 0.15 / Math.max(models.length - 1, 1),
+      estimatedCost,
+      healthStatus: String(cb?.state ?? "CLOSED"),
+      quotaAvailable: q?.percentRemaining ?? 100,
+    };
+  });
+
+  emit(simulatedPath, globalOpts, simulateSchema);
+
+  if (opts.explain && !globalOpts.quiet) {
+    const primary = simulatedPath[0];
+    const fallbacks = simulatedPath.slice(1).map((s) => s.provider);
+    process.stderr.write(`\nPrimary: ${primary?.provider} / ${primary?.model}\n`);
+    if (fallbacks.length > 0) {
+      process.stderr.write(`Fallbacks: ${fallbacks.join(" → ")}\n`);
+    }
+    const costs = simulatedPath.map((s) => s.estimatedCost);
+    process.stderr.write(
+      `Est. cost range: $${Math.min(...costs).toFixed(4)} – $${Math.max(...costs).toFixed(4)}\n`
+    );
+  }
+}
+
+function normalizeCombos(raw) {
+  if (Array.isArray(raw)) return raw;
+  if (raw && Array.isArray(raw.combos)) return raw.combos;
+  if (raw && Array.isArray(raw.data)) return raw.data;
+  return [];
+}
+
+function getComboModels(combo, modelFallback) {
+  const steps = combo.steps ?? combo.models ?? combo.targets ?? [];
+  return steps.map((step) => ({
+    provider: step.provider ?? step.providerId ?? "",
+    model: step.model ?? step.modelId ?? modelFallback ?? "auto",
+    inputCostPer1M: step.inputCostPer1M ?? step.costPer1MInput ?? 0,
+  }));
+}
+
+function toArray(val) {
+  if (Array.isArray(val)) return val;
+  return [];
+}