"use client";

import { useCallback, useEffect, useRef, useState } from "react";
import { AiPinnedCityCard } from "@/components/dashboard/scan-terminal/AiPinnedCityCard";
import { findDetailForCity } from "@/components/dashboard/scan-terminal/city-detail-utils";
import { findRowForCity, normalizeCityKey } from "@/components/dashboard/scan-terminal/decision-utils";
import type { AiPinnedCity } from "@/components/dashboard/scan-terminal/types";
import type { CityDetail, ScanOpportunityRow } from "@/lib/dashboard-types";

export function AiPinnedForecastView({
  items,
  rows,
  detailsByName,
  locale,
  onRefreshCityDetail,
  onRemoveCity,
}: {
  items: AiPinnedCity[];
  rows: ScanOpportunityRow[];
  detailsByName: Record<string, CityDetail>;
  locale: string;
  onRefreshCityDetail: (cityName: string) => Promise<void>;
  onRemoveCity: (cityName: string) => void;
}) {
  const isEn = locale === "en-US";
  const [expandedCityKey, setExpandedCityKey] = useState<string | null>(null);
  const [removingCities, setRemovingCities] = useState<Set<string>>(
    () => new Set(),
  );
  const cityCardRefs = useRef<Record<string, HTMLDivElement | null>>({});
  const knownCityKeysRef = useRef<Set<string>>(new Set());
  const previousFirstCityKeyRef = useRef<string | null>(null);
  const removeTimersRef = useRef<Map<string, ReturnType<typeof setTimeout>>>(new Map());

  useEffect(() => {
    const activeKeyList = items.map(
      (item) => normalizeCityKey(item.cityName) || item.cityName,
    );
    const activeKeys = new Set(activeKeyList);
    const firstCityKey = activeKeyList[0] ?? null;
    const hasNewCity = activeKeyList.some((key) => !knownCityKeysRef.current.has(key));
    const firstCityChanged = firstCityKey !== previousFirstCityKeyRef.current;

    setExpandedCityKey((current) => {
      if (!firstCityKey) return null;
      if (hasNewCity || firstCityChanged) return firstCityKey;
      if (current && activeKeys.has(current)) return current;
      return firstCityKey;
    });
    Object.keys(cityCardRefs.current).forEach((key) => {
      if (!activeKeys.has(key)) {
        delete cityCardRefs.current[key];
      }
    });
    knownCityKeysRef.current = activeKeys;
    previousFirstCityKeyRef.current = firstCityKey;
  }, [items]);

  useEffect(() => {
    return () => {
      removeTimersRef.current.forEach((timer) => clearTimeout(timer));
      removeTimersRef.current.clear();
    };
  }, []);

  const removeCityWithMotion = useCallback(
    (item: AiPinnedCity, stableKey: string) => {
      if (removeTimersRef.current.has(stableKey)) return;
      setRemovingCities((current) => {
        const next = new Set(current);
        next.add(stableKey);
        return next;
      });
      const timer = setTimeout(() => {
        onRemoveCity(item.cityName);
        setRemovingCities((current) => {
          const next = new Set(current);
          next.delete(stableKey);
          return next;
        });
        removeTimersRef.current.delete(stableKey);
      }, 260);
      removeTimersRef.current.set(stableKey, timer);
    },
    [onRemoveCity],
  );

  const scrollToCity = useCallback((stableKey: string) => {
    cityCardRefs.current[stableKey]?.scrollIntoView({
      behavior: "smooth",
      block: "start",
    });
  }, []);

  const focusCity = useCallback((stableKey: string) => {
    setExpandedCityKey(stableKey);
    window.requestAnimationFrame(() => scrollToCity(stableKey));
  }, [scrollToCity]);

  if (!items.length) {
    return (
      <div className="scan-ai-workspace empty">
        <div className="scan-empty-state">
          <div className="scan-empty-title">
            {isEn ? "Click a city on the map" : "从分布视图点击城市"}
          </div>
          <div className="scan-empty-copy">
            {isEn
              ? "Selected cities will appear here as deep analysis blocks."
              : "被点击的城市会加入深度分析页，并保留为城市分析区块。"}
          </div>
        </div>
      </div>
    );
  }

  return (
    <div className="scan-ai-workspace">
      <div className="scan-ai-workspace-head">
        <div>
          <span>{isEn ? "Selected city workspace" : "城市分析工作区"}</span>
          <strong>
            {isEn
              ? `${items.length} cities under deep analysis`
              : `${items.length} 个城市正在深度分析`}
          </strong>
        </div>
        <p>
          {isEn
            ? "Map clicks add cities here. City analysis stays here until you remove it."
            : "地图点击会把城市加入这里；城市分析会保留，直到你手动移除。"}
        </p>
      </div>
      <div className="scan-ai-city-jumpbar" aria-label={isEn ? "Selected city shortcuts" : "已选城市快捷跳转"}>
        {items.map((item) => {
          const stableKey = normalizeCityKey(item.cityName) || item.cityName;
          return (
            <button
              key={stableKey}
              type="button"
              onClick={() => focusCity(stableKey)}
            >
              {item.cityName}
            </button>
          );
        })}
      </div>
      <div className="scan-ai-city-stack">
        {items.map((item) => {
          const detail = findDetailForCity(detailsByName, item.cityName);
          const row = findRowForCity(rows, item.cityName);
          const key = normalizeCityKey(item.cityName);
          const stableKey = key || item.cityName;
          return (
            <div
              key={stableKey}
              ref={(node) => {
                cityCardRefs.current[stableKey] = node;
              }}
              className="scan-ai-city-anchor"
            >
              <AiPinnedCityCard
                item={item}
                detail={detail}
                row={row}
                locale={locale}
                collapsed={expandedCityKey !== stableKey}
                removing={removingCities.has(stableKey)}
                onRefreshCityDetail={onRefreshCityDetail}
                onRemove={() => removeCityWithMotion(item, stableKey)}
                onToggleCollapsed={() => {
                  setExpandedCityKey((current) =>
                    current === stableKey ? null : stableKey,
                  );
                }}
              />
            </div>
          );
        })}
      </div>
    </div>
  );
}