import type { CalendarEntryState, SubscriptionCalendarEntry, SubscriptionMediaKind } from "@umt/contracts";
import { CalendarDays, ChevronLeft, ChevronRight } from "lucide-react";
import { Link } from "react-router";
import { useSubscriptionCalendar } from "~/api/subscriptions.ts";
import { EmptyState, ErrorState, LoadingState } from "~/components/console/empty-state.tsx";
import { consolePath } from "~/components/console/nav.ts";
import { Button } from "~/components/ui/button.tsx";
import { cn } from "~/lib/utils.ts";
import {
  CALENDAR_STATE_LABEL,
  entriesByDate,
  monthGrid,
  monthKey,
  monthStart,
  SUB_KIND_LABEL,
  shiftMonth,
  todayKey,
} from "./model.ts";

// 订阅日历(设计 §4):月视图,事件 = 追踪中订阅范围内集的播出日期(同日同季聚合),电影取上映日期。
// 状态色只表示入库状态:已入库 success、部分 warning、未入库 destructive、未播出无彩。条目链到订阅详情。

const WEEKDAYS = ["一", "二", "三", "四", "五", "六", "日"];

const STATE_CLS: Record<CalendarEntryState, string> = {
  have: "border-success/40 bg-success/10",
  partial: "border-warning/40 bg-warning/10",
  missing: "border-destructive/40 bg-destructive/10",
  upcoming: "border-border bg-foreground/[0.04]",
};
const DOT_CLS: Record<CalendarEntryState, string> = {
  have: "bg-success",
  partial: "bg-warning",
  missing: "bg-destructive",
  upcoming: "bg-muted-foreground/50",
};

function Entry({ e }: { e: SubscriptionCalendarEntry }) {
  return (
    <Link
      to={consolePath("subscriptions", e.subscriptionId)}
      title={`${e.title} ${e.label} · ${CALENDAR_STATE_LABEL[e.state]}${e.total > 1 ? ` ${e.have}/${e.total}` : ""}`}
      className={cn(
        "flex min-w-0 items-center gap-1 rounded-tight border px-1.5 py-0.5 text-meta text-foreground transition-colors duration-micro hover:bg-foreground/[0.06]",
        STATE_CLS[e.state],
      )}
    >
      <span aria-hidden className={cn("h-1.5 w-1.5 shrink-0 rounded-full", DOT_CLS[e.state])} />
      <span className="truncate">{e.title}</span>
      <span className="shrink-0 text-muted-foreground tabular-nums">{e.label}</span>
      <span className="sr-only">{CALENDAR_STATE_LABEL[e.state]}</span>
    </Link>
  );
}

export function SubscriptionCalendarView({
  month,
  onMonth,
  mediaKind,
}: {
  /** YYYY-MM;空 = 本月 */
  month: string;
  onMonth: (m: string) => void;
  mediaKind?: SubscriptionMediaKind | undefined;
}) {
  const first = monthStart(month);
  const grid = monthGrid(first);
  const from = grid[0]!.date;
  const to = grid.at(-1)!.date;
  const q = useSubscriptionCalendar(from, to, mediaKind);
  const byDate = entriesByDate(q.data?.entries ?? []);
  const today = todayKey();
  const title = `${first.getFullYear()} 年 ${first.getMonth() + 1} 月`;
  const unknown = q.data?.unknown ?? [];

  return (
    <section aria-label="订阅日历" className="space-y-3">
      <div className="flex flex-wrap items-center gap-2">
        <Button
          variant="ghost"
          size="icon-sm"
          aria-label="上个月"
          onClick={() => onMonth(monthKey(shiftMonth(first, -1)))}
        >
          <ChevronLeft />
        </Button>
        <h2 className="min-w-28 text-center text-body font-semibold text-foreground tabular-nums">{title}</h2>
        <Button
          variant="ghost"
          size="icon-sm"
          aria-label="下个月"
          onClick={() => onMonth(monthKey(shiftMonth(first, 1)))}
        >
          <ChevronRight />
        </Button>
        <Button variant="ghost" size="sm" onClick={() => onMonth("")}>
          本月
        </Button>
        <ul className="ml-auto flex flex-wrap gap-x-3 gap-y-1 text-meta text-muted-foreground">
          {(Object.keys(CALENDAR_STATE_LABEL) as CalendarEntryState[]).map((k) => (
            <li key={k} className="flex items-center gap-1.5">
              <span aria-hidden className={cn("h-2 w-2 rounded-full", DOT_CLS[k])} />
              {CALENDAR_STATE_LABEL[k]}
            </li>
          ))}
        </ul>
      </div>

      {q.isPending ? (
        <LoadingState rows={5} />
      ) : q.isError ? (
        <ErrorState error={q.error} onRetry={() => q.refetch()} />
      ) : (
        <>
          <div className="overflow-x-auto scroll-bleed">
            <div className="pg-slab grid min-w-[640px] grid-cols-7 overflow-hidden rounded-xl">
              {WEEKDAYS.map((w) => (
                <div
                  key={w}
                  className="border-b border-border/60 px-2 py-1.5 text-meta font-medium text-muted-foreground"
                >
                  周{w}
                </div>
              ))}
              {grid.map((d, i) => {
                const list = byDate.get(d.date) ?? [];
                return (
                  <div
                    key={d.date}
                    className={cn(
                      "min-h-24 min-w-0 space-y-1 border-border/60 p-1.5",
                      i % 7 !== 6 && "border-r",
                      i < grid.length - 7 && "border-b",
                      !d.inMonth && "bg-foreground/[0.02]",
                    )}
                  >
                    <time
                      dateTime={d.date}
                      className={cn(
                        "block text-meta tabular-nums",
                        d.inMonth ? "text-muted-foreground" : "text-muted-foreground/50",
                        d.date === today && "font-semibold text-foreground",
                      )}
                    >
                      {Number(d.date.slice(8, 10))}
                      {d.date === today ? <span className="ml-1">今天</span> : null}
                    </time>
                    {list.map((e) => (
                      <Entry key={`${e.subscriptionId}-${e.seasonNumber ?? ""}-${e.date}`} e={e} />
                    ))}
                  </div>
                );
              })}
            </div>
          </div>
          {!q.data?.entries.length && !unknown.length ? (
            <EmptyState icon={CalendarDays} title="这个月没有播出" description="追踪中的订阅有播出日期后出现在这里。" />
          ) : null}
          {unknown.length ? (
            <section aria-labelledby="cal-unknown" className="space-y-2">
              <h3 id="cal-unknown" className="text-body font-semibold text-foreground">
                播出日期未知
                <span className="ml-1.5 text-meta font-normal text-muted-foreground tabular-nums">
                  {unknown.length}
                </span>
              </h3>
              <p className="text-meta text-muted-foreground">TMDB 还没有给出这些集的播出日期，元数据刷新后更新。</p>
              <ul className="pg-slab divide-y divide-border/60 overflow-hidden rounded-xl">
                {unknown.map((u) => (
                  <li key={`${u.subscriptionId}-${u.seasonNumber ?? ""}`}>
                    <Link
                      to={consolePath("subscriptions", u.subscriptionId)}
                      className="flex min-w-0 items-center gap-2 px-3 py-2 text-sm text-foreground hover:bg-foreground/[0.04]"
                    >
                      <span className="truncate">{u.title}</span>
                      <span className="shrink-0 text-meta text-muted-foreground">
                        {SUB_KIND_LABEL[u.mediaKind]}
                        {u.seasonNumber !== null ? ` · S${String(u.seasonNumber).padStart(2, "0")}` : ""}
                        {u.episodes.length ? ` · ${u.episodes.length} 集` : ""}
                      </span>
                    </Link>
                  </li>
                ))}
              </ul>
            </section>
          ) : null}
        </>
      )}
    </section>
  );
}