import { useState } from "react";
import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import { toast } from "sonner";
import { archiveAnnouncement, createAnnouncement, fetchAnnouncements, updateAnnouncement, type AnnouncementCategory, type PortalAnnouncement } from "../api/announcements";
import { PageHeader } from "../components/common/PageHeader";
import { Button } from "../components/ui/button";
import { Input } from "../components/ui/input";
import { Label } from "../components/ui/label";
import { Tabs, TabsList, TabsTrigger } from "../components/ui/tabs";
import { Textarea } from "../components/ui/textarea";
import { formatDisplayDate, formatDisplayDateTime } from "../lib/displayFormat";

function toChinaEndOfDayIso(value: string) {
  if (!value) return null;
  return new Date(`${value}T23:59:59+08:00`).toISOString();
}

function acknowledgementModeLabel(category: AnnouncementCategory, requiresAcknowledgement: boolean) {
  return category === "policy" || requiresAcknowledgement ? "制度签收" : "普通公告";
}

function formatSummary(item: PortalAnnouncement) {
  const summary = item.acknowledgementSummary;
  if (!summary?.required) return "无需签收";
  return `已签 ${summary.acknowledgedCount}/${summary.totalActiveEmployees} · 待签 ${summary.pendingCount}`;
}

export function PortalAnnouncementsPage() {
  const queryClient = useQueryClient();
  const [title, setTitle] = useState("");
  const [summary, setSummary] = useState("");
  const [linkUrl, setLinkUrl] = useState("");
  const [priority, setPriority] = useState("100");
  const [mode, setMode] = useState<AnnouncementCategory>("general");
  const [acknowledgementStatement, setAcknowledgementStatement] = useState("我已阅读并理解该制度，确认按公司制度执行。");
  const [acknowledgementDueDate, setAcknowledgementDueDate] = useState("");

  const listQuery = useQuery({ queryKey: ["announcements", "manage"], queryFn: () => fetchAnnouncements(true) });
  const refresh = () => queryClient.invalidateQueries({ queryKey: ["announcements"] });
  const isPolicy = mode === "policy";

  const createMutation = useMutation({
    mutationFn: () => createAnnouncement({
      title,
      summary,
      linkUrl: linkUrl || null,
      priority: Number(priority || 100),
      category: mode,
      requiresAcknowledgement: isPolicy,
      acknowledgementStatement: isPolicy ? acknowledgementStatement.trim() : null,
      acknowledgementDueAt: isPolicy ? toChinaEndOfDayIso(acknowledgementDueDate) : null,
    }),
    onSuccess: async () => {
      setTitle("");
      setSummary("");
      setLinkUrl("");
      setPriority("100");
      setMode("general");
      setAcknowledgementStatement("我已阅读并理解该制度，确认按公司制度执行。");
      setAcknowledgementDueDate("");
      await refresh();
      toast.success("公告已创建");
    },
    onError: () => {
      toast.error("公告创建失败，请检查填写内容");
    },
  });

  const archiveMutation = useMutation({
    mutationFn: archiveAnnouncement,
    onSuccess: async () => {
      await refresh();
      toast.success("公告已归档");
    },
  });

  const toggleMutation = useMutation({
    mutationFn: ({ id, enabled }: { id: string; enabled: boolean }) => updateAnnouncement(id, { enabled }),
    onSuccess: async () => {
      await refresh();
      toast.success("公告状态已更新");
    },
  });

  const handleCreate = () => {
    if (!title.trim() || !summary.trim()) {
      toast.error("请填写标题和摘要");
      return;
    }
    if (isPolicy && !acknowledgementStatement.trim()) {
      toast.error("制度签收公告必须填写签收声明");
      return;
    }
    createMutation.mutate();
  };

  return (
    <div className="space-y-6">
      <PageHeader title="公告管理" subtitle="发布普通公告，或创建需要全员显式确认的制度签收公告。" />
      <div className="admin-workspace-grid xl:grid-cols-[360px,minmax(0,1fr)]">
        <section className="admin-command-panel space-y-4 p-5">
          <div>
            <h2 className="text-base font-semibold text-zinc-900">新建公告</h2>
            <p className="mt-1 text-xs leading-5 text-zinc-500">制度内容变化时请新建公告版本，不直接覆盖已签收内容。</p>
          </div>

          <div className="space-y-2">
            <Label>公告类型</Label>
            <Tabs value={mode} onValueChange={(value) => setMode(value as AnnouncementCategory)}>
              <TabsList className="grid h-auto w-full grid-cols-2">
                <TabsTrigger value="general">普通公告</TabsTrigger>
                <TabsTrigger value="policy">制度签收</TabsTrigger>
              </TabsList>
            </Tabs>
          </div>

          <div className="space-y-2">
            <Label>标题</Label>
            <Input value={title} onChange={(event) => setTitle(event.target.value)} placeholder="例如：费用报销制度签收" />
          </div>
          <div className="space-y-2">
            <Label>摘要</Label>
            <Textarea value={summary} onChange={(event) => setSummary(event.target.value)} placeholder="写清楚适用范围、入口和处理要求。" />
          </div>
          <div className="space-y-2">
            <Label>链接</Label>
            <Input value={linkUrl} onChange={(event) => setLinkUrl(event.target.value)} placeholder="https://..." />
          </div>

          {isPolicy ? (
            <div className="rounded-lg border border-slate-200 bg-slate-50/70 p-3.5">
              <div className="space-y-2">
                <Label>签收声明</Label>
                <Textarea
                  className="min-h-[88px]"
                  value={acknowledgementStatement}
                  onChange={(event) => setAcknowledgementStatement(event.target.value)}
                />
              </div>
              <div className="mt-3 space-y-2">
                <Label>签收截止日</Label>
                <Input type="date" value={acknowledgementDueDate} onChange={(event) => setAcknowledgementDueDate(event.target.value)} />
                <p className="text-xs leading-5 text-zinc-500">按国内习惯，截止日当天 23:59 前均视为未逾期。</p>
              </div>
            </div>
          ) : null}

          <div className="space-y-2">
            <Label>优先级</Label>
            <Input value={priority} onChange={(event) => setPriority(event.target.value)} inputMode="numeric" />
          </div>
          <Button type="button" disabled={createMutation.isPending} onClick={handleCreate}>
            {createMutation.isPending ? "创建中..." : isPolicy ? "创建制度签收公告" : "创建公告"}
          </Button>
        </section>

        <section className="admin-command-panel space-y-4 p-5">
          <div className="flex flex-col gap-2 md:flex-row md:items-end md:justify-between">
            <div>
              <h2 className="text-base font-semibold text-zinc-900">公告列表</h2>
              <p className="mt-1 text-xs leading-5 text-zinc-500">管理员可查看制度签收统计；未签名单仅展示员工号和姓名。</p>
            </div>
            {listQuery.isFetching ? <span className="badge-neutral">刷新中</span> : null}
          </div>

          <div className="space-y-3">
            {(listQuery.data?.items ?? []).map((item) => {
              const summaryStats = item.acknowledgementSummary;
              const pendingEmployees = item.pendingEmployees ?? [];
              const pendingPreview = pendingEmployees.slice(0, 6);
              return (
                <article key={item.id} className="admin-tile-card space-y-3">
                  <div className="flex flex-col gap-3 md:flex-row md:items-start md:justify-between">
                    <div className="min-w-0">
                      <div className="flex flex-wrap items-center gap-2">
                        <h3 className="font-semibold text-zinc-900">{item.title}</h3>
                        <span className={item.requiresAcknowledgement ? "badge-warning" : "badge-neutral"}>
                          {acknowledgementModeLabel(item.category, item.requiresAcknowledgement)}
                        </span>
                        <span className={item.enabled ? "badge-success" : "badge-neutral"}>{item.enabled ? "启用" : "停用"}</span>
                      </div>
                      <p className="mt-2 text-sm leading-6 text-zinc-600">{item.summary}</p>
                      <div className="mt-2 flex flex-wrap gap-2 text-xs text-zinc-500">
                        <span>优先级 {item.priority}</span>
                        <span>更新 {formatDisplayDateTime(item.updatedAt)}</span>
                        {item.acknowledgementDueAt ? <span>截止 {formatDisplayDate(item.acknowledgementDueAt)}</span> : null}
                      </div>
                    </div>
                    <div className="flex shrink-0 gap-2">
                      <Button type="button" variant="secondary" size="sm" onClick={() => toggleMutation.mutate({ id: item.id, enabled: !item.enabled })}>
                        {item.enabled ? "停用" : "启用"}
                      </Button>
                      <Button type="button" variant="secondary" size="sm" onClick={() => archiveMutation.mutate(item.id)}>归档</Button>
                    </div>
                  </div>

                  {item.requiresAcknowledgement && summaryStats ? (
                    <div className="rounded-lg border border-slate-200 bg-slate-50/70 p-3.5">
                      <div className="grid gap-2 text-sm md:grid-cols-4">
                        <div><span className="text-zinc-500">范围</span><div className="font-semibold text-zinc-900">{summaryStats.totalActiveEmployees} 人</div></div>
                        <div><span className="text-zinc-500">已签</span><div className="font-semibold text-emerald-700">{summaryStats.acknowledgedCount} 人</div></div>
                        <div><span className="text-zinc-500">待签</span><div className="font-semibold text-amber-700">{summaryStats.pendingCount} 人</div></div>
                        <div><span className="text-zinc-500">逾期</span><div className="font-semibold text-red-700">{summaryStats.overdueCount} 人</div></div>
                      </div>
                      <div className="mt-3 text-xs font-semibold text-zinc-500">{formatSummary(item)}</div>
                      {pendingPreview.length ? (
                        <div className="mt-2 flex flex-wrap gap-2">
                          {pendingPreview.map((employee) => (
                            <span key={employee.id} className={employee.status === "overdue" ? "badge-error" : "badge-warning"}>
                              {employee.employeeNo} · {employee.name}
                            </span>
                          ))}
                          {pendingEmployees.length > pendingPreview.length ? (
                            <span className="badge-neutral">另 {pendingEmployees.length - pendingPreview.length} 人</span>
                          ) : null}
                        </div>
                      ) : (
                        <div className="mt-2 text-sm text-emerald-700">当前 active 员工均已签收。</div>
                      )}
                    </div>
                  ) : null}
                </article>
              );
            })}
            {!listQuery.data?.items?.length ? <div className="text-sm text-zinc-500">暂无公告</div> : null}
          </div>
        </section>
      </div>
    </div>
  );
}