"use client";

import Link from "next/link";
import { useSearchParams } from "next/navigation";
import { useEffect, useMemo, useState } from "react";
import { Plus, ScanSearch, Settings2 } from "lucide-react";
import { Badge } from "@/components/ui/badge";
import { Button } from "@/components/ui/button";
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
import { Input } from "@/components/ui/input";
import { TopicFormDialog } from "@/components/inspiration/topic-form-dialog";
import { EmptyState } from "@/components/layout/empty-state";
import { PageHeader } from "@/components/layout/page-header";
import { notify } from "@/lib/notifications/store";
import {
  TOPIC_GOAL_LABELS,
  isPlacementGoal,
  parseTopicGoal,
  type TopicGoal,
} from "@/lib/types/topic-goal";
import { parseFetchJson } from "@/lib/utils";

interface TopicListItem {
  id: string;
  label: string;
  query: string;
  topicGoal: string;
  scanCount: number;
  latestScan: {
    id: string;
    createdAt: string;
    itemCount: number;
  } | null;
}

export default function ScansPage() {
  const searchParams = useSearchParams();
  const [topics, setTopics] = useState<TopicListItem[]>([]);
  const mode: TopicGoal = parseTopicGoal(searchParams.get("mode"));
  const [search, setSearch] = useState("");
  const [createOpen, setCreateOpen] = useState(false);
  const [loading, setLoading] = useState(true);

  async function load() {
    setLoading(true);
    try {
      const res = await fetch("/api/topics");
      const data = await parseFetchJson<{ topics?: TopicListItem[]; error?: string }>(res);
      if (!res.ok) {
        notify({ type: "error", title: "載入主題失敗", message: data.error });
        setTopics([]);
        return;
      }
      setTopics(data.topics ?? []);
    } catch (err) {
      const message = err instanceof Error ? err.message : "載入失敗";
      notify({ type: "error", title: "載入找靈感失敗", message });
      setTopics([]);
    } finally {
      setLoading(false);
    }
  }

  useEffect(() => {
    load();
  }, []);

  const modeTopics = useMemo(
    () =>
      topics.filter((t) =>
        isPlacementGoal(t.topicGoal) ? mode === "placement" : mode === "viral"
      ),
    [topics, mode]
  );

  const filteredTopics = useMemo(() => {
    const q = search.trim().toLowerCase();
    if (!q) return modeTopics;
    return modeTopics.filter(
      (t) => t.label.toLowerCase().includes(q) || t.query.toLowerCase().includes(q)
    );
  }, [modeTopics, search]);

  return (
    <div>
      <PageHeader
        eyebrow={mode === "viral" ? "HAIXUN" : "FIND YOUR TA"}
        title={mode === "viral" ? "建立主題海巡任務" : "建立高意向受眾任務"}
        description={mode === "viral" ? "設定要模仿的內容主題，Extension 會使用你的 Threads session 進行抓取與分析。" : "設定產品與受眾關鍵字，找出有需求訊號的人並生成人設置入話術。"}
        action={
          <Button size="sm" onClick={() => setCreateOpen(true)}>
            <Plus className="h-3.5 w-3.5" />
            新增任務
          </Button>
        }
      />

      <div className="mb-5 space-y-3">
        <Input
          value={search}
          onChange={(e) => setSearch(e.target.value)}
          placeholder="搜尋主題名稱或種子關鍵字…"
          className="max-w-sm"
        />
      </div>

      <TopicFormDialog
        open={createOpen}
        onOpenChange={setCreateOpen}
        defaultGoal={mode}
        onCreated={load}
      />

      {loading ? (
        <div className="py-16 text-center text-[13px] text-muted-foreground">載入中…</div>
      ) : filteredTopics.length === 0 ? (
        <EmptyState
          icon={ScanSearch}
          title={modeTopics.length === 0 ? "尚無此模式的主題" : "找不到符合的主題"}
          description={
            modeTopics.length === 0
              ? "按「新增任務」開始建立第一個任務"
              : "試試其他關鍵字，或清除搜尋"
          }
          action={
            modeTopics.length === 0 ? (
              <Button size="sm" onClick={() => setCreateOpen(true)}>
                新增任務
              </Button>
            ) : (
              <Button size="sm" variant="outline" onClick={() => setSearch("")}>
                清除搜尋
              </Button>
            )
          }
        />
      ) : (
        <div className="grid gap-4 sm:grid-cols-2">
          {filteredTopics.map((topic, i) => {
            const goal = isPlacementGoal(topic.topicGoal) ? "placement" : "viral";
            const hasScans = topic.scanCount > 0;

            return (
              <Card
                key={topic.id}
                className="animate-fade-in-up"
                style={{ animationDelay: `${i * 40}ms` }}
              >
                <CardHeader className="pb-3">
                  <div className="flex items-start justify-between gap-2">
                    <div className="min-w-0">
                      <CardTitle className="truncate">{topic.label}</CardTitle>
                      <CardDescription className="mt-1 truncate">{topic.query}</CardDescription>
                    </div>
                    <Badge variant={goal === "placement" ? "secondary" : "default"}>
                      {TOPIC_GOAL_LABELS[goal]}
                    </Badge>
                  </div>
                </CardHeader>
                <CardContent className="space-y-3">
                  {topic.latestScan ? (
                    <p className="text-[13px] text-muted-foreground">
                      最近海巡 {new Date(topic.latestScan.createdAt).toLocaleString("zh-TW")}
                      {" · "}
                      {topic.latestScan.itemCount} 篇
                      {" · "}
                      共 {topic.scanCount} 次海巡
                    </p>
                  ) : (
                    <p className="text-[13px] text-muted-foreground">尚未海巡</p>
                  )}
                  <div className="flex flex-wrap gap-2">
                    <Button size="sm" variant="outline" asChild>
                      <Link href={`/scans/${topic.id}`}>
                        <Settings2 className="h-3.5 w-3.5" />
                        設定主題
                      </Link>
                    </Button>
                    {hasScans ? (
                      <Button size="sm" asChild>
                        <Link href={`/scans/${topic.id}/results`}>
                          <ScanSearch className="h-3.5 w-3.5" />
                          查看海巡
                        </Link>
                      </Button>
                    ) : (
                      <Button size="sm" disabled title="請先完成海巡">
                        <ScanSearch className="h-3.5 w-3.5" />
                        查看海巡
                      </Button>
                    )}
                  </div>
                </CardContent>
              </Card>
            );
          })}
        </div>
      )}
    </div>
  );
}