import { AlertTriangleIcon, Loader2Icon } from "lucide-react";
import { useEffect, useState, type FormEvent } from "react";
import type { MachineOperationPolicy, UpdateMachineOperationPolicyRequest } from "@opengeni/sdk";
import { useOpenGeniText, type OpenGeniText } from "../../messages/runtime";

export type MachineOperationPolicyEditorProps = {
  policy: MachineOperationPolicy;
  memorySupported: boolean;
  cpuSupported: boolean;
  saving?: boolean | undefined;
  onSave: (request: UpdateMachineOperationPolicyRequest) => Promise<unknown> | unknown;
};

function fieldValue(value: number | null): string {
  return value === null ? "" : String(value);
}

function parseByteCount(t: OpenGeniText, label: string, value: string): number | null {
  const trimmed = value.trim();
  if (!trimmed) return null;
  if (!/^\d+$/.test(trimmed)) {
    throw new Error(t("machines.machineOperationPolicy.bytesNotWholeNumber", { label }));
  }
  const parsed = Number(trimmed);
  if (!Number.isSafeInteger(parsed) || parsed <= 0) {
    throw new Error(t("machines.machineOperationPolicy.bytesNotPositive", { label }));
  }
  return parsed;
}

function parseCpuMillicores(t: OpenGeniText, value: string): number | null {
  const trimmed = value.trim();
  if (!trimmed) return null;
  if (!/^\d+$/.test(trimmed)) {
    throw new Error(t("machines.machineOperationPolicy.cpuNotWholeNumber"));
  }
  const parsed = Number(trimmed);
  if (!Number.isSafeInteger(parsed) || parsed <= 0 || parsed > 0xffff_ffff) {
    throw new Error(t("machines.machineOperationPolicy.cpuOutOfRange"));
  }
  return parsed;
}

/** Exact editor for the optional per-enrollment command resource policy. Blank
 * values remain genuinely unrestricted; CPU is a period-independent ratio. */
export function MachineOperationPolicyEditor({
  policy,
  memorySupported,
  cpuSupported,
  saving = false,
  onSave,
}: MachineOperationPolicyEditorProps) {
  const t = useOpenGeniText();
  const [memoryMaxBytes, setMemoryMaxBytes] = useState(fieldValue(policy.memoryMaxBytes));
  const [memoryHighBytes, setMemoryHighBytes] = useState(fieldValue(policy.memoryHighBytes));
  const [cpuMaxMillicores, setCpuMaxMillicores] = useState(fieldValue(policy.cpuMaxMillicores));
  const [validationError, setValidationError] = useState<string | null>(null);

  useEffect(() => {
    setMemoryMaxBytes(fieldValue(policy.memoryMaxBytes));
    setMemoryHighBytes(fieldValue(policy.memoryHighBytes));
    setCpuMaxMillicores(fieldValue(policy.cpuMaxMillicores));
    setValidationError(null);
  }, [policy.memoryMaxBytes, policy.memoryHighBytes, policy.cpuMaxMillicores, policy.revision]);

  const submit = async (event: FormEvent<HTMLFormElement>) => {
    event.preventDefault();
    try {
      const max = parseByteCount(
        t,
        t("machines.machineOperationPolicy.hardCeiling"),
        memoryMaxBytes,
      );
      const high = parseByteCount(
        t,
        t("machines.machineOperationPolicy.reclaimThreshold"),
        memoryHighBytes,
      );
      if (max !== null && high !== null && high > max) {
        throw new Error(t("machines.machineOperationPolicy.reclaimAboveCeiling"));
      }
      const cpuMax = parseCpuMillicores(t, cpuMaxMillicores);
      setValidationError(null);
      await onSave({
        memoryMaxBytes: max,
        memoryHighBytes: high,
        cpuMaxMillicores: cpuMax,
        expectedRevision: policy.revision,
      });
    } catch (error) {
      setValidationError(error instanceof Error ? error.message : String(error));
    }
  };

  const configured =
    policy.memoryMaxBytes !== null ||
    policy.memoryHighBytes !== null ||
    policy.cpuMaxMillicores !== null;
  const memoryConfigured = policy.memoryMaxBytes !== null || policy.memoryHighBytes !== null;
  const unsupportedMemory = memoryConfigured && !memorySupported;
  const unsupportedCpu = policy.cpuMaxMillicores !== null && (!memorySupported || !cpuSupported);

  return (
    <section
      data-machine-operation-policy
      className="rounded-og-lg border border-og-border bg-og-surface-1 p-4 shadow-og-sm"
    >
      <div className="flex flex-col gap-1">
        <h2 className="text-og-sm font-semibold text-og-fg">
          {t("machines.machineOperationPolicy.perCommandResourcePolicy")}
        </h2>
        <p className="text-og-xs leading-relaxed text-og-fg-muted">
          {t("machines.machineOperationPolicy.optionalLimitsAppliedSeparatelyTo")}
        </p>
      </div>

      {configured && (unsupportedMemory || unsupportedCpu) ? (
        <div className="mt-3 flex gap-2 rounded-og-md border border-og-status-failed/40 bg-og-status-failed/5 p-3 text-og-xs text-og-status-failed">
          <AlertTriangleIcon className="mt-0.5 size-3.5 shrink-0" aria-hidden />
          <span>
            {unsupportedCpu
              ? t("machines.machineOperationPolicy.thisRunnerCannotEnforceThe")
              : t("machines.machineOperationPolicy.thisRunnerCannotEnforceThe2")}{" "}
            {t("machines.machineOperationPolicy.commandExecutionFailsClosedUntil")}
          </span>
        </div>
      ) : null}

      <form className="mt-4 grid gap-3 sm:grid-cols-2" onSubmit={submit}>
        <label className="flex flex-col gap-1.5 text-og-xs text-og-fg-muted">
          {t("machines.machineOperationPolicy.hardCeilingBytes")}
          <input
            inputMode="numeric"
            pattern="[0-9]*"
            value={memoryMaxBytes}
            onChange={(event) => setMemoryMaxBytes(event.target.value)}
            placeholder={t("machines.machineOperationPolicy.unlimited")}
            disabled={saving}
            className="min-h-9 rounded-og-sm border border-og-border bg-og-bg px-2.5 font-og-mono text-og-sm text-og-fg outline-hidden focus-visible:ring-2 focus-visible:ring-og-accent/50 disabled:opacity-60"
          />
        </label>
        <label className="flex flex-col gap-1.5 text-og-xs text-og-fg-muted">
          {t("machines.machineOperationPolicy.reclaimThresholdBytes")}
          <input
            inputMode="numeric"
            pattern="[0-9]*"
            value={memoryHighBytes}
            onChange={(event) => setMemoryHighBytes(event.target.value)}
            placeholder={t("machines.machineOperationPolicy.unlimited")}
            disabled={saving}
            className="min-h-9 rounded-og-sm border border-og-border bg-og-bg px-2.5 font-og-mono text-og-sm text-og-fg outline-hidden focus-visible:ring-2 focus-visible:ring-og-accent/50 disabled:opacity-60"
          />
        </label>
        <label className="flex flex-col gap-1.5 text-og-xs text-og-fg-muted">
          {t("machines.machineOperationPolicy.cpuMaximumMillicores")}
          <input
            inputMode="numeric"
            pattern="[0-9]*"
            value={cpuMaxMillicores}
            onChange={(event) => setCpuMaxMillicores(event.target.value)}
            placeholder={t("machines.machineOperationPolicy.unlimited")}
            disabled={saving}
            className="min-h-9 rounded-og-sm border border-og-border bg-og-bg px-2.5 font-og-mono text-og-sm text-og-fg outline-hidden focus-visible:ring-2 focus-visible:ring-og-accent/50 disabled:opacity-60"
          />
          <span>{t("machines.machineOperationPolicy.n1000MillicoresOneCpuCore")}</span>
        </label>
        <div className="flex min-h-9 items-center justify-between gap-3 sm:col-span-2">
          <span
            role={validationError ? "alert" : undefined}
            className="text-og-xs text-og-status-failed"
          >
            {validationError}
          </span>
          <button
            type="submit"
            disabled={saving}
            className="inline-flex min-h-9 items-center gap-1.5 rounded-og-sm border border-og-primary-border bg-og-primary text-og-primary-fg px-3 py-1.5 text-og-xs font-medium transition-colors hover:bg-og-primary-hover disabled:cursor-not-allowed disabled:opacity-60"
          >
            {saving ? <Loader2Icon className="size-3.5 animate-spin" aria-hidden /> : null}
            {t("machines.machineOperationPolicy.savePolicy")}
          </button>
        </div>
      </form>
    </section>
  );
}