import { useCallback, useEffect, useRef, useState } from "react";
import { useParams, useSearchParams } from "react-router-dom";
import { AppShell } from "../components/AppShell";
import { TaskDetail } from "../components/TaskDetail";
import { ChevronRight, Plus, TicketIcon } from "../components/icons";
import {
  Button,
  EmptyState,
  InlineAlert,
  PageHeader,
  Sheet,
  SkeletonRows,
  StatusPill,
  useToast,
} from "../components/ui";
import { ApiError, api } from "../lib/client";
import { STATUS_LABEL } from "../lib/parse";
import type { Item, Member, Ticket } from "../lib/types";

const ROLES = [
  { key: "assigned", label: "派给我的", desc: "别人等你的" },
  { key: "requested", label: "我发起的", desc: "你等别人的" },
  { key: "all", label: "全部", desc: "工作区所有工单" },
] as const;

const STATUS_FILTERS = [
  { key: "", label: "全部状态" },
  { key: "open", label: "待接收" },
  { key: "accepted", label: "待办理" },
  { key: "in_progress", label: "办理中" },
  { key: "pending_verify", label: "待验收" },
  { key: "done", label: "已完成" },
] as const;

export function TicketsPage() {
  const { wsId = "" } = useParams();
  const [searchParams, setSearchParams] = useSearchParams();
  const [role, setRole] = useState<(typeof ROLES)[number]["key"]>("assigned");
  const [status, setStatus] = useState<string>("");
  const [tickets, setTickets] = useState<Ticket[]>([]);
  const [cursor, setCursor] = useState<string | null>(null);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);
  // 从通知点进来时带 ?open=<id>，落地即展开那一条
  const [openId, setOpenId] = useState<string | null>(searchParams.get("open"));
  const reqId = useRef(0);
  const { push: toast } = useToast();

  // 手工开单：这条路径不经过任何任务，所以人得自己选
  const [members, setMembers] = useState<Member[]>([]);
  const [creating, setCreating] = useState(false);
  const [formTitle, setFormTitle] = useState("");
  const [formBody, setFormBody] = useState("");
  const [formAssignee, setFormAssignee] = useState("");
  const [formPriority, setFormPriority] = useState(1);
  const [formDue, setFormDue] = useState("");
  const [saving, setSaving] = useState(false);

  useEffect(() => {
    if (!wsId) return;
    let alive = true;
    void api
      .get<{ items: Member[] }>(`/workspaces/${wsId}/members?limit=100`)
      .then((page) => {
        if (alive) setMembers(page.items);
      })
      .catch(() => {
        /* 成员拉不到时，表单里就没人可选，但不该拦住列表 */
      });
    return () => {
      alive = false;
    };
  }, [wsId]);

  const load = useCallback(
    async (nextCursor: string | null) => {
      // 切 tab / 切状态会连发请求，慢的回来会盖掉新结果，用序号丢弃过期响应
      const mine = ++reqId.current;
      setLoading(true);
      setError(null);
      try {
        const qs = new URLSearchParams({ role });
        if (status) qs.set("status", status);
        if (nextCursor) qs.set("cursor", nextCursor);
        const page = await api.get<{
          tickets: Ticket[];
          next_cursor: string | null;
          has_more: boolean;
        }>(`/workspaces/${wsId}/tickets?${qs.toString()}`);
        if (mine !== reqId.current) return;
        setTickets((prev) => (nextCursor ? [...prev, ...page.tickets] : page.tickets));
        setCursor(page.has_more ? page.next_cursor : null);
      } catch (err) {
        if (mine !== reqId.current) return;
        setError(err instanceof ApiError ? err.message : "工单加载失败");
      } finally {
        if (mine === reqId.current) setLoading(false);
      }
    },
    [wsId, role, status],
  );

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

  async function quickAction(ticket: Ticket, action: string, body: Record<string, unknown> = {}) {
    try {
      await api.post(`/workspaces/${wsId}/items/${ticket.id}/ticket/${action}`, {
        version: ticket.version,
        ...body,
      });
      void load(null);
    } catch (err) {
      if (err instanceof ApiError && err.code === 4009) {
        setError("这条刚被别人改过，已为你刷新列表");
        void load(null);
        return;
      }
      setError(err instanceof ApiError ? err.message : "操作失败");
    }
  }

  const currentRole = ROLES.find((r) => r.key === role);

  async function createTicket() {
    if (!formTitle.trim()) {
      setError("工单得有个标题，别人才能知道要办什么");
      return;
    }
    if (!formAssignee) {
      setError("先选一个人——工单不指派就等于没人接");
      return;
    }
    setSaving(true);
    setError(null);
    try {
      const created = await api.post<Ticket>(`/workspaces/${wsId}/tickets`, {
        title: formTitle.trim(),
        body_md: formBody.trim() || null,
        assignee_id: formAssignee,
        priority: formPriority,
        due_at: formDue ? new Date(formDue).toISOString() : null,
      });
      setCreating(false);
      setFormTitle("");
      setFormBody("");
      setFormAssignee("");
      setFormDue("");
      setFormPriority(1);
      setRole("requested");
      toast("工单已开出，对方会收到通知", "success");
      setOpenId(created.id);
    } catch (err) {
      setError(err instanceof ApiError ? err.message : "开单失败");
    } finally {
      setSaving(false);
    }
  }

  return (
    <AppShell wsId={wsId} active="tickets">
      <PageHeader
        title="工单"
        desc="待接 → 办理中 → 待验收 → 完成。验收通过后，当初卡住的那条任务会自动回到待办。"
        eyebrow={<>需要别人搭把手的事，都在这里</>}
        actions={
          <>
            <select
              className="input h-9 w-36 text-sm"
              value={status}
              onChange={(e) => setStatus(e.target.value)}
              aria-label="按状态筛选"
            >
              {STATUS_FILTERS.map((s) => (
                <option key={s.key} value={s.key}>
                  {s.label}
                </option>
              ))}
            </select>
            <Button variant="primary" size="sm" onClick={() => setCreating(true)}>
              <Plus size={14} />
              新建工单
            </Button>
          </>
        }
      />

      <div className="mb-4 inline-flex items-center gap-0.5 rounded-xl border border-line-200 bg-paper-50 p-0.5">
        {ROLES.map((r) => {
          const active = role === r.key;
          return (
            <button
              key={r.key}
              onClick={() => setRole(r.key)}
              title={r.desc}
              className={`rounded-[9px] px-3 py-1.5 text-sm font-medium transition-colors ${
                active
                  ? "bg-white text-ink-900 shadow-sm ring-1 ring-line-200"
                  : "text-ink-500 hover:text-ink-800"
              }`}
            >
              {r.label}
            </button>
          );
        })}
      </div>

      {error && (
        <div className="mb-4">
          <InlineAlert>{error}</InlineAlert>
        </div>
      )}

      {loading && tickets.length === 0 ? (
        <div className="card overflow-hidden">
          <SkeletonRows rows={3} />
        </div>
      ) : tickets.length === 0 ? (
        <div className="card">
          <EmptyState
            icon={<TicketIcon size={18} />}
            title={role === "assigned" ? "没有等你的工单" : "这里还空着"}
            hint={
              role === "assigned"
                ? "别人把事交给你办时，这里会出现；要主动找人帮忙，去任务详情点「升级成工单」。"
                : currentRole?.desc
            }
          />
        </div>
      ) : (
        <ul className="grid gap-2 md:grid-cols-2 2xl:grid-cols-3">
          {tickets.map((t) => (
            <li
              key={t.id}
              className="card group p-0 transition hover:border-line-300 hover:shadow-pop"
            >
              <div className="flex items-start justify-between gap-3 p-4">
                <button className="min-w-0 flex-1 text-left" onClick={() => setOpenId(t.id)}>
                  <div className="flex items-center gap-2">
                    <StatusPill status={t.status} label={STATUS_LABEL[t.status]} />
                    {t.ticket.reject_count > 0 && (
                      <span className="pill bg-rust-50 text-rust-500">
                        退回 {t.ticket.reject_count} 次
                      </span>
                    )}
                  </div>
                  <p className="mt-1.5 truncate text-[15px] font-semibold leading-6 text-ink-900 group-hover:text-primary-700">
                    {t.title}
                  </p>
                  <p className="mt-1 flex flex-wrap items-center gap-x-2 gap-y-0.5 text-2xs text-ink-400">
                    <span>更新 {new Date(t.updated_at).toLocaleString("zh-CN")}</span>
                    {t.due_at ? (
                      <span>截止 {new Date(t.due_at).toLocaleDateString("zh-CN")}</span>
                    ) : null}
                    {t.tags.map((tag) => (
                      <span key={tag.id}>#{tag.name}</span>
                    ))}
                  </p>
                </button>

                <div className="flex shrink-0 items-center gap-1.5">
                  {t.status === "open" && (
                    <Button variant="primary" size="sm" onClick={() => void quickAction(t, "accept")}>
                      接收
                    </Button>
                  )}
                  {t.status === "accepted" && (
                    <Button variant="primary" size="sm" onClick={() => void quickAction(t, "start")}>
                      开始
                    </Button>
                  )}
                  {t.status === "pending_verify" && (
                    <Button
                      variant="primary"
                      size="sm"
                      onClick={() => void quickAction(t, "verify", { approve: true })}
                    >
                      通过
                    </Button>
                  )}
                  <Button variant="ghost" size="sm" onClick={() => setOpenId(t.id)}>
                    详情
                    <ChevronRight size={13} />
                  </Button>
                </div>
              </div>
            </li>
          ))}
        </ul>
      )}

      {cursor && (
        <div className="mt-4 text-center">
          <Button variant="ghost" disabled={loading} onClick={() => void load(cursor)}>
            {loading ? "加载中…" : "加载更多"}
          </Button>
        </div>
      )}

      {/* 手工开单：不经过任务，直接把一件要别人帮忙的事开成工单 */}
      <Sheet
        open={creating}
        onClose={() => setCreating(false)}
        size="xl"
        title="新建工单"
        subtitle="不是从任务升级来的也可以——写清楚要办什么，指定一个人。"
        footer={
          <>
            <Button variant="ghost" onClick={() => setCreating(false)} disabled={saving}>
              取消
            </Button>
            <Button variant="primary" onClick={() => void createTicket()} disabled={saving}>
              {saving ? "正在开单…" : "开单并通知对方"}
            </Button>
          </>
        }
      >
        <div className="space-y-5">
          <div>
            <label className="label" htmlFor="ticket-title">
              要办什么
            </label>
            <input
              id="ticket-title"
              className="input"
              value={formTitle}
              onChange={(e) => setFormTitle(e.target.value)}
              placeholder="一句能直接看懂的话，例如：核对 9 月发票与报销单"
              maxLength={200}
              autoFocus
            />
          </div>

          <div>
            <label className="label" htmlFor="ticket-body">
              详细说明（可选）
            </label>
            <textarea
              id="ticket-body"
              className="input min-h-[96px] resize-y text-sm leading-6"
              value={formBody}
              onChange={(e) => setFormBody(e.target.value)}
              placeholder="背景、已有的线索、验收标准…对方看到的就是这些"
            />
          </div>

          <div className="grid gap-4 sm:grid-cols-2">
            <div>
              <label className="label" htmlFor="ticket-assignee">
                交给谁
              </label>
              <select
                id="ticket-assignee"
                className="input"
                value={formAssignee}
                onChange={(e) => setFormAssignee(e.target.value)}
              >
                <option value="">选择一个人…</option>
                {members.map((m) => (
                  <option key={m.user_id} value={m.user_id}>
                    {m.nickname || m.user_id.slice(0, 8)}
                  </option>
                ))}
              </select>
            </div>
            <div>
              <label className="label" htmlFor="ticket-priority">
                优先级
              </label>
              <select
                id="ticket-priority"
                className="input"
                value={formPriority}
                onChange={(e) => setFormPriority(Number(e.target.value))}
              >
                <option value={0}>无</option>
                <option value={1}>低</option>
                <option value={2}>中</option>
                <option value={3}>高</option>
              </select>
            </div>
          </div>

          <div>
            <label className="label" htmlFor="ticket-due">
              希望什么时候办好（可选）
            </label>
            <input
              id="ticket-due"
              type="datetime-local"
              className="input"
              value={formDue}
              onChange={(e) => setFormDue(e.target.value)}
            />
          </div>

          <p className="rounded-xl border border-line-200 bg-paper-200/60 px-3.5 py-2.5 text-2xs leading-5 text-ink-500">
            开出后对方会收到通知，并按「待接 → 办理中 → 待验收 → 完成」推进。
            手工开的单没有来源任务，验收通过后不会回流任何任务，但同样会沉淀一份知识草稿。
          </p>
        </div>
      </Sheet>

      {openId && (
        <TaskDetail
          wsId={wsId}
          itemId={openId}
          onClose={() => {
            setOpenId(null);
            if (searchParams.get("open")) setSearchParams({}, { replace: true });
          }}
          onChanged={(updated: Item) =>
            setTickets((prev) => prev.map((t) => (t.id === updated.id ? { ...t, ...updated } : t)))
          }
          onDeleted={(id) => {
            setTickets((prev) => prev.filter((t) => t.id !== id));
            setOpenId(null);
          }}
          onTicketChanged={() => {
            void load(null);
          }}
        />
      )}
    </AppShell>
  );
}