import { useEffect, useMemo, useState } from "react";
import { Pause, Play, RotateCcw, SkipForward } from "lucide-react";
import {
  FLOW_ORDER,
  FRAMES,
  LEARNING_ORDER,
  PLANES,
  RUNTIME_ORDER,
  SAFETY_ORDER,
  STAGES,
  type StageId,
} from "../../data/autonomy";
import { FlowArrow, StageCard } from "./StageCard";
import { StageDetail } from "./StageDetail";

type Props = {
  openStage: StageId | null;
  onOpenStage: (id: StageId | null) => void;
};

const PHASES: { key: string; label: string; stages: StageId[] }[] = [
  { key: "sense", label: "Sense", stages: ["sensors", "fusion"] },
  { key: "understand", label: "Understand", stages: ["perception"] },
  { key: "predict", label: "Predict", stages: ["prediction"] },
  { key: "decide", label: "Decide", stages: ["behavior", "motion"] },
  { key: "act", label: "Act", stages: ["control", "actuators"] },
  { key: "verify", label: "Verify", stages: ["supervisor"] },
  { key: "learn", label: "Learn", stages: ["capture"] },
];

const TICK_MS = 1500;

const CYCLE: StageId[] = [...RUNTIME_ORDER, "world"];

export function AutonomyStack({ openStage, onOpenStage }: Props) {
  const [playing, setPlaying] = useState(true);
  const [tick, setTick] = useState(0);

  useEffect(() => {
    if (!playing) return;
    const id = window.setInterval(() => setTick((t) => t + 1), TICK_MS);
    return () => window.clearInterval(id);
  }, [playing]);

  const cycle = Math.floor(tick / CYCLE.length);
  const activeRuntime = CYCLE[tick % CYCLE.length]!;
  const frame = FRAMES[cycle % FRAMES.length]!;
  const activeLearning = LEARNING_ORDER[Math.floor(tick / 3) % LEARNING_ORDER.length]!;
  const overriding = frame.safety === "override";
  const gating = activeRuntime === "control" || activeRuntime === "actuators";

  const phase = useMemo(
    () => PHASES.find((item) => item.stages.includes(activeRuntime))?.key ?? "sense",
    [activeRuntime],
  );

  const activeIds = useMemo(() => {
    const set = new Set<StageId>([activeRuntime, activeLearning]);
    if (gating || overriding) set.add("supervisor");
    if (overriding) set.add("fallback");
    return set;
  }, [activeLearning, activeRuntime, gating, overriding]);

  const step = () => {
    setPlaying(false);
    setTick((t) => t + 1);
  };

  const detail = openStage ? STAGES[openStage] : null;
  const detailIndex = openStage ? FLOW_ORDER.indexOf(openStage) : -1;

  return (
    <section aria-label="Autonomy stack emulator" className="space-y-5">
      <div className="rounded-xl border border-white/10 bg-[#0e1624] p-4">
        <h2 className="font-mono text-[10px] tracking-[0.22em] text-cyan-200/80 uppercase">
          Closed loop
        </h2>
        <ol className="mt-3 flex flex-wrap items-center gap-x-2 gap-y-2">
          {PHASES.map((item, index) => (
            <li key={item.key} className="flex items-center gap-2">
              <span
                className={`rounded-md border px-2.5 py-1 text-xs transition-colors ${
                  phase === item.key
                    ? "border-cyan-300/70 bg-cyan-400/15 text-white"
                    : "border-white/10 text-slate-400"
                }`}
              >
                {item.label}
              </span>
              {index < PHASES.length - 1 ? (
                <span aria-hidden className="text-slate-600">
                  →
                </span>
              ) : null}
            </li>
          ))}
        </ol>
        <p className="mt-3 text-sm leading-relaxed text-slate-400">
          An autonomy stack is not a pipeline that ends. Every action changes
          the world, the sensors measure the change, and the loop runs again —
          typically ten to twenty times a second.
        </p>
      </div>

      <div className="sticky top-0 z-20 rounded-xl border border-white/10 bg-[#0b1220]/95 p-3 backdrop-blur-md sm:p-4">
        <div className="flex flex-wrap items-center justify-between gap-3">
          <div className="min-w-0">
            <p className="font-mono text-[10px] tracking-[0.22em] text-cyan-200/80 uppercase">
              Scenario · {frame.label} · cycle {cycle + 1}
            </p>
            <p className="text-sm font-medium text-white">{frame.headline}</p>
          </div>
          <div className="flex items-center gap-2">
            <span
              className={`rounded-md border px-2.5 py-1 font-mono text-[10px] tracking-wide uppercase ${
                overriding
                  ? "border-rose-400/60 bg-rose-500/15 text-rose-100"
                  : "border-emerald-400/40 bg-emerald-500/10 text-emerald-100"
              }`}
            >
              {overriding ? "Safety override" : "Nominal"}
            </span>
            <button
              type="button"
              onClick={() => setPlaying((value) => !value)}
              aria-label={playing ? "Pause emulator" : "Play emulator"}
              className="inline-flex min-h-11 items-center gap-1.5 rounded-md border border-white/15 bg-white/5 px-3 py-2 text-xs text-slate-100 hover:bg-white/10"
            >
              {playing ? <Pause className="h-3.5 w-3.5" /> : <Play className="h-3.5 w-3.5" />}
              {playing ? "Pause" : "Play"}
            </button>
            <button
              type="button"
              onClick={step}
              aria-label="Step one stage"
              className="inline-flex min-h-11 items-center gap-1.5 rounded-md border border-white/15 bg-white/5 px-3 py-2 text-xs text-slate-100 hover:bg-white/10"
            >
              <SkipForward className="h-3.5 w-3.5" />
              Step
            </button>
            <button
              type="button"
              onClick={() => {
                setTick(0);
                setPlaying(true);
              }}
              aria-label="Restart emulator"
              className="inline-flex min-h-11 items-center gap-1.5 rounded-md border border-white/15 bg-white/5 px-3 py-2 text-xs text-slate-100 hover:bg-white/10"
            >
              <RotateCcw className="h-3.5 w-3.5" />
              Restart
            </button>
          </div>
        </div>
      </div>

      <div className="grid gap-5 lg:grid-cols-[minmax(0,1.25fr)_minmax(15rem,0.85fr)]">
        <div className="min-w-0">
          <h3 className="mb-3 font-mono text-[10px] tracking-[0.22em] text-slate-500 uppercase">
            Autonomy runtime
          </h3>
          <StageCard
            stage={STAGES.mission}
            active={false}
            readout={frame.readouts.mission}
            alwaysShowReadout
            onOpen={() => onOpenStage("mission")}
          />
          <FlowArrow label="route + constraints" />
          {RUNTIME_ORDER.map((id, index) => (
            <div key={id}>
              <StageCard
                stage={STAGES[id]}
                active={activeIds.has(id)}
                alert={overriding && (id === "control" || id === "actuators")}
                readout={frame.readouts[id]}
                onOpen={() => onOpenStage(id)}
              />
              {index === RUNTIME_ORDER.length - 1 ? null : (
                <FlowArrow
                  label={
                    id === "motion" ? "proposed trajectory → safety check" : undefined
                  }
                />
              )}
            </div>
          ))}
          <FlowArrow label="force applied to the world" />
          <StageCard
            stage={STAGES.world}
            active={activeIds.has("world")}
            readout={frame.readouts.world}
            onOpen={() => onOpenStage("world")}
          />
          <p className="mt-3 rounded-lg border border-dashed border-cyan-300/30 bg-cyan-400/5 px-3 py-2.5 text-xs leading-relaxed text-cyan-100/90">
            ↺ The world feeds the sensor layer again. This edge is what turns a
            perception model into a control system.
          </p>
        </div>

        <div className="space-y-6">
          <div>
            <h3 className="mb-1 font-mono text-[10px] tracking-[0.22em] text-slate-500 uppercase">
              Safety &amp; supervision
            </h3>
            <p className="mb-3 text-xs leading-relaxed text-slate-500">
              Sits between the planner and the actuators with independent
              authority to say no.
            </p>
            <div className="space-y-2">
              {SAFETY_ORDER.map((id) => (
                <StageCard
                  key={id}
                  stage={STAGES[id]}
                  compact
                  active={activeIds.has(id)}
                  alert={overriding}
                  readout={frame.readouts[id]}
                  alwaysShowReadout={id === "health"}
                  onOpen={() => onOpenStage(id)}
                />
              ))}
            </div>
          </div>

          <div>
            <h3 className="mb-1 font-mono text-[10px] tracking-[0.22em] text-slate-500 uppercase">
              Data &amp; learning plane
            </h3>
            <p className="mb-3 text-xs leading-relaxed text-slate-500">
              Runs offline, on fleet time rather than frame time. This is the
              autonomy development stack.
            </p>
            {frame.capture ? (
              <p className="mb-3 rounded-md border border-emerald-400/40 bg-emerald-500/10 px-3 py-2 font-mono text-[11px] text-emerald-100">
                event captured · {frame.capture}
              </p>
            ) : null}
            <div className="space-y-2">
              {LEARNING_ORDER.map((id) => (
                <StageCard
                  key={id}
                  stage={STAGES[id]}
                  compact
                  active={activeIds.has(id)}
                  readout={frame.readouts[id]}
                  onOpen={() => onOpenStage(id)}
                />
              ))}
            </div>
            <p className="mt-3 rounded-lg border border-dashed border-emerald-300/30 bg-emerald-400/5 px-3 py-2.5 text-xs leading-relaxed text-emerald-100/90">
              ↺ Release feeds the runtime. The autonomy stack drives the car;
              this loop is what makes next month's car better.
            </p>
          </div>
        </div>
      </div>

      <div className="rounded-xl border border-white/10 bg-[#0e1624] p-4">
        <h3 className="font-mono text-[10px] tracking-[0.22em] text-slate-500 uppercase">
          Six interacting planes
        </h3>
        <div className="mt-3 grid gap-2 sm:grid-cols-2">
          {(Object.keys(PLANES) as (keyof typeof PLANES)[]).map((key) => (
            <div
              key={key}
              className="rounded-lg border border-white/10 px-3 py-2"
              style={{ boxShadow: `inset 3px 0 0 ${PLANES[key].accent}` }}
            >
              <p
                className="font-mono text-[10px] tracking-[0.18em] uppercase"
                style={{ color: PLANES[key].accent }}
              >
                {PLANES[key].label}
              </p>
              <p className="mt-1 text-xs leading-relaxed text-slate-400">
                {PLANES[key].blurb}
              </p>
            </div>
          ))}
        </div>
        <p className="mt-4 text-sm leading-relaxed text-slate-400">
          There is no single "AI" box. Learning shows up in perception, fusion,
          the world model, prediction, behavior, motion costs, simulation, and
          scenario mining — while safety stays deliberately deterministic around
          all of it.
        </p>
      </div>

      {detail ? (
        <StageDetail
          stage={detail}
          live={frame.readouts[detail.id]}
          neighbors={{
            prev: FLOW_ORDER[(detailIndex - 1 + FLOW_ORDER.length) % FLOW_ORDER.length]!,
            next: FLOW_ORDER[(detailIndex + 1) % FLOW_ORDER.length]!,
          }}
          onOpen={onOpenStage}
          onClose={() => onOpenStage(null)}
        />
      ) : null}
    </section>
  );
}