"use client";

import { useEffect, useState } from "react";
import { BrainCircuit, ListRestart } from "lucide-react";
import { Button } from "@/components/ui/button";
import { Textarea } from "@/components/ui/textarea";
import { ZenCard } from "@/components/ui/zen-card";
import { ModeWorkspace } from "@/components/layout/mode-workspace";
import Result from "@/components/result";
import ResultAI from "@/components/result-ai";
import DateTimePicker, {
  nowDateString,
  nowTimeString,
} from "@/components/shared/datetime-picker";
import HexagramInput from "@/components/shared/hexagram-input";
import RegionSelect, {
  useRegionLocation,
} from "@/components/shared/region-select";
import { streamAiCompletion } from "@/lib/ai/client-stream";
import { saveHistoryEntry } from "@/lib/history/storage";
import type { GuaResult } from "@/lib/calc/hexagram";
import todayJson from "@/lib/data/today.json";

const todayData: string[] = todayJson;

export default function LiuyaoForm() {
  const [question, setQuestion] = useState("");
  const [provinceCode, setProvinceCode] = useState("");
  const [cityCode, setCityCode] = useState("");
  const [calcDate, setCalcDate] = useState(nowDateString);
  const [calcTime, setCalcTime] = useState(nowTimeString);
  const [castMode, setCastMode] = useState<"online" | "offline">("online");
  const [castActive, setCastActive] = useState(false);
  const [guaData, setGuaData] = useState<GuaResult | null>(null);
  const [completion, setCompletion] = useState("");
  const [error, setError] = useState("");
  const [isLoading, setIsLoading] = useState(false);

  const location = useRegionLocation(provinceCode, cityCode);
  const formReady = question.trim() !== "" && location !== null;

  useEffect(() => {
    setCastActive(false);
    setGuaData(null);
  }, [provinceCode, cityCode, castMode, question]);

  function validate(): string | null {
    if (!question.trim()) {
      return "请输入问事";
    }
    if (!location) {
      return "请选择起卦省份";
    }
    if (!guaData) {
      return "请先完成 6 次起卦";
    }
    return null;
  }

  async function handleAnalyze() {
    const err = validate();
    if (err) {
      setError(err);
      return;
    }

    setError("");
    setCompletion("");
    setIsLoading(true);

    try {
      const text = await streamAiCompletion(
        {
          mode: "liuyao",
          payload: {
            question,
            calcDate,
            calcTime,
            locationName: location!.name,
            longitude: location!.longitude,
            guaMark: guaData!.result.guaMark,
            guaTitle: guaData!.result.guaTitle,
            guaResult: guaData!.result.guaResult,
            guaChange: guaData!.result.guaChange,
          },
        },
        setCompletion,
      );
      await saveHistoryEntry({
        mode: "liuyao",
        title: guaData!.result.guaTitle,
        question,
        summary: guaData!.result.guaResult,
        completion: text,
        hexagram: {
          guaMark: guaData!.result.guaMark,
          guaTitle: guaData!.result.guaTitle,
          guaResult: guaData!.result.guaResult,
          guaChange: guaData!.result.guaChange,
        },
        meta: {
          地域: location!.name,
          起卦时间: `${calcDate} ${calcTime}`,
          卦象: guaData!.result.guaTitle,
        },
      });
    } catch (e) {
      setError(e instanceof Error ? e.message : String(e));
    } finally {
      setIsLoading(false);
    }
  }

  function handleReset() {
    setQuestion("");
    setProvinceCode("");
    setCityCode("");
    setCalcDate(nowDateString());
    setCalcTime(nowTimeString());
    setCastMode("online");
    setCastActive(false);
    setGuaData(null);
    setCompletion("");
    setError("");
    setIsLoading(false);
  }

  function handleGuaResult(data: GuaResult) {
    setGuaData(data);
    setCompletion("");
    setError("");
  }

  const downloadPreamble =
    guaData && location
      ? `# 六爻算卦 AI 解读\n\n- 问事：${question}\n- 地域：${location.name}\n- 时间：${calcDate} ${calcTime}\n- 卦象：${guaData.result.guaTitle}\n`
      : undefined;

  return (
    <ModeWorkspace
      aiPanel={
        <ResultAI
          panel
          completion={completion}
          isLoading={isLoading}
          onCompletion={handleAnalyze}
          error={error}
          emptyHint="完成起卦后，点击「AI 解读」"
          downloadFilename={
            completion && guaData
              ? `六爻-${guaData.result.guaTitle.replace(/[/\\?%*:|"<>]/g, "-")}.md`
              : undefined
          }
          downloadPreamble={downloadPreamble}
        />
      }
    >
      <ZenCard title="问事 · 心意" subtitle="所求何事，心诚则灵">
        <Textarea
          placeholder="您想算点什么？"
          value={question}
          onChange={(e) => setQuestion(e.target.value)}
          rows={3}
          className="border-border/60 bg-background/50"
        />
        <div className="flex flex-wrap gap-2">
          {todayData.map((item, index) => (
            <button
              key={index}
              type="button"
              onClick={() => setQuestion(item)}
              className="rounded-full border border-border/60 bg-secondary/50 px-3 py-1 text-xs text-muted-foreground transition hover:border-primary/30 hover:text-foreground"
            >
              {item}
            </button>
          ))}
        </div>
      </ZenCard>

      <ZenCard title="起卦 · 时空" subtitle="地域、时辰与六爻">
        <RegionSelect
          label="起卦地域"
          provinceCode={provinceCode}
          cityCode={cityCode}
          onProvinceChange={setProvinceCode}
          onCityChange={setCityCode}
        />
        <DateTimePicker
          label="起卦时辰"
          date={calcDate}
          time={calcTime}
          onDateChange={setCalcDate}
          onTimeChange={setCalcTime}
        />
        <div className="flex gap-2">
          <Button
            type="button"
            size="sm"
            variant={castMode === "online" ? "default" : "outline"}
            onClick={() => {
              setCastMode("online");
              setGuaData(null);
            }}
          >
            线上摇卦
          </Button>
          <Button
            type="button"
            size="sm"
            variant={castMode === "offline" ? "default" : "outline"}
            onClick={() => {
              setCastMode("offline");
              setGuaData(null);
            }}
          >
            线下录入
          </Button>
        </div>
        <HexagramInput
          key={castMode}
          mode={castMode}
          enabled={formReady}
          active={castActive}
          onStart={() => setCastActive(true)}
          onResult={handleGuaResult}
          onClear={() => {
            setGuaData(null);
            setCastActive(false);
          }}
        />
        {guaData && (
          <div className="rounded-xl border border-primary/20 bg-primary/5 p-4">
            <Result {...guaData.result} />
          </div>
        )}
        {error && !completion && (
          <p className="text-sm text-destructive">{error}</p>
        )}
        <div className="flex gap-2 pt-1">
          <Button variant="outline" onClick={handleReset} className="flex-1">
            <ListRestart size={16} className="mr-1" />
            重来
          </Button>
          <Button
            onClick={handleAnalyze}
            disabled={!guaData || isLoading}
            className="flex-1"
          >
            <BrainCircuit size={16} className="mr-1" />
            AI 解读
          </Button>
        </div>
      </ZenCard>
    </ModeWorkspace>
  );
}