"use client";

import { useCallback, useEffect, useState } from "react";
import { Play } from "lucide-react";
import { bool } from "aimless.js";
import Coin from "@/components/coin";
import Hexagram from "@/components/hexagram";
import { Button } from "@/components/ui/button";
import {
  buildHexagramList,
  COIN_OPTIONS,
  computeGuaResult,
  type GuaResult,
  YAO_LABELS,
} from "@/lib/calc/hexagram";

const AUTO_DELAY = 800;

interface HexagramInputProps {
  mode: "online" | "offline";
  enabled: boolean;
  active: boolean;
  onStart: () => void;
  onResult: (data: GuaResult) => void;
  onClear: () => void;
}

export default function HexagramInput({
  mode,
  enabled,
  active,
  onStart,
  onResult,
  onClear,
}: HexagramInputProps) {
  const [frontList, setFrontList] = useState([true, true, true]);
  const [rotation, setRotation] = useState(false);
  const [hexagramList, setHexagramList] = useState<GuaResult["list"]>([]);
  const [offlineCounts, setOfflineCounts] = useState<(number | null)[]>(
    Array(6).fill(null),
  );

  const complete = hexagramList.length === 6;

  useEffect(() => {
    setHexagramList([]);
    setOfflineCounts(Array(6).fill(null));
    setRotation(false);
  }, [mode]);

  useEffect(() => {
    if (!active) {
      setHexagramList([]);
      setOfflineCounts(Array(6).fill(null));
      setRotation(false);
    }
  }, [active]);

  const finishList = useCallback(
    (list: GuaResult["list"]) => {
      const result = computeGuaResult(list);
      if (result) {
        onResult({ list, result });
      }
    },
    [onResult],
  );

  const onTransitionEnd = useCallback(() => {
    setRotation(false);
    const frontCount = frontList.reduce(
      (acc, val) => (val ? acc + 1 : acc),
      0,
    );
    setHexagramList((list) => {
      const newList = [
        ...list,
        {
          change: frontCount === 0 || frontCount === 3,
          yang: frontCount >= 2,
          separate: list.length === 3,
        },
      ];
      if (newList.length === 6) {
        finishList(newList);
      }
      return newList;
    });
  }, [frontList, finishList]);

  const startOnlineCast = useCallback(() => {
    if (rotation || !enabled || !active || hexagramList.length >= 6) {
      return;
    }
    setFrontList([bool(), bool(), bool()]);
    setRotation(true);
  }, [rotation, enabled, active, hexagramList.length]);

  useEffect(() => {
    if (mode !== "online" || !enabled || !active || rotation || complete) {
      return;
    }
    const timer = setTimeout(startOnlineCast, AUTO_DELAY);
    return () => clearTimeout(timer);
  }, [
    mode,
    enabled,
    active,
    rotation,
    complete,
    hexagramList.length,
    startOnlineCast,
  ]);

  function handleOfflineSelect(index: number, frontCount: number) {
    const next = [...offlineCounts];
    next[index] = frontCount;
    setOfflineCounts(next);
  }

  function confirmOffline() {
    if (offlineCounts.some((v) => v === null)) {
      return;
    }
    const list = buildHexagramList(offlineCounts as number[]);
    finishList(list);
    setHexagramList(list);
  }

  function handleReset() {
    setHexagramList([]);
    setOfflineCounts(Array(6).fill(null));
    setRotation(false);
    onClear();
  }

  const offlineReady = offlineCounts.every((v) => v !== null);

  if (!enabled) {
    return (
      <p className="text-center text-sm text-muted-foreground">
        请先填写问事、地域和起卦时辰
      </p>
    );
  }

  if (!active) {
    return (
      <div className="flex flex-col items-center gap-3 py-1">
        <p className="text-center text-sm text-muted-foreground">
          信息已填写完毕，确认无误后手动开始起卦
        </p>
        <Button type="button" onClick={onStart}>
          <Play size={16} className="mr-1" />
          开始起卦
        </Button>
      </div>
    );
  }

  return (
    <div className="flex w-full flex-col items-center gap-4">
      {mode === "online" && (
        <>
          <Coin
            onTransitionEnd={onTransitionEnd}
            frontList={frontList}
            rotation={rotation}
          />
          <span className="text-lg font-medium">
            🎲 第{" "}
            <span className="font-mono text-xl font-bold text-orange-500">
              {complete ? "6/6" : `${hexagramList.length + (rotation ? 1 : 0)}/6`}
            </span>{" "}
            次卜筮
            {rotation && (
              <span className="ml-2 text-sm text-muted-foreground">铜钱旋转中…</span>
            )}
          </span>
        </>
      )}

      {mode === "offline" && !complete && (
        <div className="w-full max-w-md space-y-2">
          <p className="text-center text-xs text-muted-foreground">
            人工抛铜钱后，按从下到上（初爻→上爻）录入每爻结果
          </p>
          {YAO_LABELS.map((label, index) => (
            <div
              key={label}
              className="flex flex-wrap items-center gap-2 rounded-md border p-2"
            >
              <span className="w-10 shrink-0 text-sm font-medium">{label}</span>
              {COIN_OPTIONS.map((opt) => (
                <button
                  key={opt.count}
                  type="button"
                  onClick={() => handleOfflineSelect(index, opt.count)}
                  className={`rounded border px-2 py-1 text-xs transition ${
                    offlineCounts[index] === opt.count
                      ? "border-primary bg-primary/10 text-primary"
                      : "hover:bg-accent"
                  }`}
                >
                  {opt.label}
                </button>
              ))}
            </div>
          ))}
          <Button
            className="w-full"
            disabled={!offlineReady}
            onClick={confirmOffline}
          >
            确认卦象
          </Button>
        </div>
      )}

      {hexagramList.length > 0 && (
        <div className="flex flex-col items-center gap-3 sm:flex-row">
          <Hexagram list={hexagramList} />
          {complete && (
            <>
              <p className="text-sm text-muted-foreground sm:max-w-[10rem]">
                六爻已齐，请在下方点击「AI 解读」
              </p>
              <Button size="sm" variant="outline" onClick={handleReset}>
                重新起卦
              </Button>
            </>
          )}
        </div>
      )}
    </div>
  );
}