import type { EpisodeGroupSetResult, EpisodeStructureSeason } from "@umt/contracts";
import { Check, Layers } from "lucide-react";
import { type ReactNode, useEffect, useState } from "react";
import { toast } from "sonner";
import { useEpisodeGroups, useEpisodeStructure, useSetEpisodeGroup } from "~/api/episode-mapping.ts";
import { ConfirmDialog } from "~/components/console/confirm-dialog.tsx";
import { ErrorState, LoadingState } from "~/components/console/empty-state.tsx";
import { PaginatedList } from "~/components/console/paginated-list.tsx";
import { StatusBadge } from "~/components/console/status-badge.tsx";
import { CoverPlaceholder } from "~/components/library/parts.tsx";
import { EpisodeRow, SeasonSection } from "~/components/media/media-detail.tsx";
import { Button } from "~/components/ui/button.tsx";
import { errorMessage } from "~/lib/api.ts";
import { cn } from "~/lib/utils.ts";
import {
  DEFAULT_STRUCTURE_LABEL,
  hasStructureChoice,
  inLibraryText,
  originText,
  type StructureOption,
  seasonLine,
  seasonTitle,
  structureOptions,
  switchDescription,
} from "./episode-structure-model.ts";

// 季集结构选择(学 MoviePilot SubscribeSeasonDialog):横向轨道选「TMDB 默认季 / 各剧集组」,
// 下面按所选结构显示季卡片;选了非当前结构时可以「改用这套结构」(改的是作品设置,先确认)。

/** 横向轨道:每个选项一张小卡(名称 + 类型 · 季数 · 集数),当前结构带勾 */
export function StructureTrack({
  options,
  value,
  onChange,
}: {
  options: StructureOption[];
  value: string | null;
  onChange: (groupId: string | null) => void;
}) {
  return (
    <fieldset aria-label="季集结构" className="m-0 min-w-0 border-0 p-0">
      <div className="scroll-bleed -mx-1 flex gap-2 overflow-x-auto px-1 pb-1">
        {options.map((o) => {
          const selected = o.groupId === value;
          return (
            <button
              key={o.groupId ?? "default"}
              type="button"
              aria-pressed={selected}
              onClick={() => onChange(o.groupId)}
              className={cn(
                "flex min-w-[9.5rem] shrink-0 cursor-pointer flex-col items-start rounded-xl border px-3 py-2 text-left transition-colors duration-base",
                selected
                  ? "pill-selected text-foreground"
                  : "border-border text-muted-foreground hover:bg-wash/[0.06] hover:text-foreground",
              )}
            >
              <span className="flex items-center gap-1 text-sm font-medium text-foreground">
                {o.current ? <Check className="h-3.5 w-3.5" aria-label="当前" /> : null}
                {o.label}
              </span>
              <span className="text-meta text-muted-foreground">{o.meta ?? (o.current ? "当前" : "按 TMDB 季")}</span>
            </button>
          );
        })}
      </div>
    </fieldset>
  );
}

/** 季卡片网格(订阅选季):海报、季名、首播年 · 集数、已入库;可选中 */
export function SeasonCardGrid({
  seasons,
  selected,
  onPick,
  disabled,
}: {
  seasons: EpisodeStructureSeason[];
  /** 选中的季号 */
  selected: number | null;
  onPick: (s: EpisodeStructureSeason) => void;
  disabled?: boolean;
}) {
  return (
    <ul className="grid grid-cols-3 gap-2 sm:grid-cols-4">
      {seasons.map((s) => {
        const on = s.seasonNumber === selected;
        const lib = inLibraryText(s);
        return (
          <li key={s.seasonNumber}>
            <button
              type="button"
              aria-pressed={on}
              disabled={disabled}
              onClick={() => onPick(s)}
              className={cn(
                "flex w-full cursor-pointer flex-col gap-1.5 rounded-xl border p-1.5 text-left transition-colors duration-base disabled:cursor-not-allowed disabled:opacity-50",
                on ? "pill-selected" : "border-border hover:bg-wash/[0.06]",
              )}
            >
              <CoverPlaceholder
                title={seasonTitle(s)}
                kind="series"
                small
                posterPath={s.posterPath}
                className="aspect-[2/3] h-auto w-full"
              />
              <span className="min-w-0 px-0.5">
                <span className="block truncate text-caption font-medium text-foreground">{seasonTitle(s)}</span>
                <span className="block text-meta text-muted-foreground tabular-nums">{seasonLine(s)}</span>
                {lib ? <span className="block text-meta text-muted-foreground tabular-nums">{lib}</span> : null}
              </span>
            </button>
          </li>
        );
      })}
    </ul>
  );
}

/** 某套结构的季折叠列表(作品页预览):季头 + 每集(集号、标题、播出日期、入库状态、原季集对照) */
export function StructurePreview({ seasons }: { seasons: EpisodeStructureSeason[] }) {
  const [open, setOpen] = useState<Set<number>>(new Set());
  const toggle = (n: number) => {
    const next = new Set(open);
    if (next.has(n)) next.delete(n);
    else next.add(n);
    setOpen(next);
  };
  return (
    <PaginatedList rows={seasons} label="季列表" className="space-y-2">
      {(s) => (
        <SeasonSection
          key={s.seasonNumber}
          s={{
            seasonNumber: s.seasonNumber,
            name: s.name,
            airDate: s.airDate,
            episodeCount: s.episodeCount,
            posterPath: s.posterPath,
            overview: null,
            summary: (
              <StatusBadge tone={s.episodeCount && s.inLibrary >= s.episodeCount ? "success" : "neutral"}>
                已入库 {s.inLibrary}/{s.episodeCount}
              </StatusBadge>
            ),
          }}
          open={open.has(s.seasonNumber)}
          onToggle={() => toggle(s.seasonNumber)}
        >
          {s.episodes.length === 0 ? (
            <p className="text-meta text-muted-foreground">TMDB 上这一季还没有集信息。</p>
          ) : (
            <PaginatedList
              rows={s.episodes}
              as="ul"
              compact
              label={`第 ${s.seasonNumber} 季集列表`}
              className="divide-y divide-border/60"
            >
              {(e) => (
                <EpisodeRow
                  key={e.episodeNumber}
                  e={{
                    key: String(e.episodeNumber),
                    seasonNumber: s.seasonNumber,
                    episodeNumber: e.episodeNumber,
                    name: e.name,
                    overview: null,
                    airDate: e.airDate,
                    runtime: null,
                    stillPath: null,
                    voteAverage: null,
                    status: e.inLibrary ? { label: "已入库", tone: "success" } : { label: "未入库", tone: "neutral" },
                    extra: originText(s.seasonNumber, e) ? (
                      <p className="mt-0.5 font-mono text-meta text-muted-foreground">
                        {originText(s.seasonNumber, e)}
                      </p>
                    ) : null,
                  }}
                />
              )}
            </PaginatedList>
          )}
        </SeasonSection>
      )}
    </PaginatedList>
  );
}

function resultToast(r: EpisodeGroupSetResult) {
  const name = r.current?.name ?? DEFAULT_STRUCTURE_LABEL;
  const parts = [`改按「${name}」分季`];
  if (r.moved) parts.push(`${r.moved} 集换了季集号`);
  if (r.unmatched.length) parts.push(`${r.unmatched.length} 集对不上、已标临时`);
  if (r.reresolve.changed) parts.push(`${r.reresolve.changed} 条资源重新换算`);
  toast.success(parts.join("，"));
}

/**
 * 作品页「季与集」顶部的季集结构切换:只有 TMDB 有剧集组(或作品已选了剧集组)时出现。
 * 选中当前结构时显示 children(现有的季与集);选中其它结构时显示该结构的季卡片预览与「改用这套结构」。
 */
export function EpisodeStructureSwitcher({ entityId, children }: { entityId: string; children: ReactNode }) {
  const groups = useEpisodeGroups(entityId);
  const options = structureOptions(groups.data);
  const current = groups.data?.current?.groupId ?? null;
  const [picked, setPicked] = useState<string | null | undefined>(undefined);
  const selected = picked === undefined ? current : picked;
  const viewingOther = selected !== current;
  const structure = useEpisodeStructure(entityId, selected, viewingOther);
  const setGroup = useSetEpisodeGroup(entityId);
  const [confirm, setConfirm] = useState(false);
  if (!hasStructureChoice(groups.data)) return <>{children}</>;
  const target = options.find((o) => o.groupId === selected);
  return (
    <div className="space-y-3">
      <div className="space-y-1.5">
        <p className="flex items-center gap-1.5 text-meta text-muted-foreground">
          <Layers className="h-3.5 w-3.5" aria-hidden />
          季集结构
        </p>
        <StructureTrack options={options} value={selected} onChange={setPicked} />
      </div>
      {!viewingOther ? (
        children
      ) : (
        <div className="space-y-3">
          <div className="flex flex-wrap items-center justify-between gap-2 rounded-xl border border-dashed border-border px-3 py-2">
            <p className="text-caption text-muted-foreground">
              预览「{target?.label ?? DEFAULT_STRUCTURE_LABEL}」的分季，已入库按 TMDB 原季集对照。
            </p>
            <Button size="sm" disabled={setGroup.isPending} onClick={() => setConfirm(true)}>
              改用这套结构
            </Button>
          </div>
          {structure.isPending ? (
            <LoadingState rows={2} />
          ) : structure.error ? (
            <ErrorState error={structure.error} onRetry={() => structure.refetch()} />
          ) : (
            <StructurePreview seasons={structure.data?.seasons ?? []} />
          )}
        </div>
      )}
      <ConfirmDialog
        open={confirm}
        onOpenChange={setConfirm}
        title={`改按「${target?.label ?? DEFAULT_STRUCTURE_LABEL}」分季？`}
        description={switchDescription(target?.label ?? DEFAULT_STRUCTURE_LABEL)}
        confirmLabel="改用"
        onConfirm={async () => {
          try {
            resultToast(await setGroup.mutateAsync(selected));
            setPicked(undefined);
          } catch (err) {
            toast.error(errorMessage(err, "切换失败"));
            throw err;
          }
        }}
      />
    </div>
  );
}

/**
 * 订阅表单的选季(学 MP):作品有剧集组时用轨道 + 季卡片代替下拉;选了非当前结构的季要先确认改作品设置,
 * 改完按新结构的同号季单元回填。没有剧集组时返回 null,表单照用下拉。
 */
export function SubscriptionSeasonPicker({
  entityId,
  value,
  onChange,
  disabled,
}: {
  entityId: string;
  /** 选中的季单元 id;"" = 全部季 */
  value: string;
  onChange: (seasonUnitId: string) => void;
  disabled?: boolean;
}) {
  const groups = useEpisodeGroups(entityId);
  const current = groups.data?.current?.groupId ?? null;
  const [picked, setPicked] = useState<string | null | undefined>(undefined);
  const selected = picked === undefined ? current : picked;
  const structure = useEpisodeStructure(entityId, selected, hasStructureChoice(groups.data));
  const setGroup = useSetEpisodeGroup(entityId);
  const [ask, setAsk] = useState<EpisodeStructureSeason | null>(null);
  const [after, setAfter] = useState<number | null>(null);
  const currentData = structure.data?.current ? structure.data : null;
  // 改完结构后,按新结构里同号季的季单元回填
  useEffect(() => {
    if (after === null || !currentData) return;
    const hit = currentData.seasons.find((s) => s.seasonNumber === after);
    if (hit?.seasonUnitId) onChange(hit.seasonUnitId);
    setAfter(null);
  }, [after, currentData, onChange]);
  if (!hasStructureChoice(groups.data)) return null;
  const options = structureOptions(groups.data);
  const seasons = structure.data?.seasons ?? [];
  const selectedSeason = structure.data?.current
    ? (seasons.find((s) => s.seasonUnitId && s.seasonUnitId === value)?.seasonNumber ?? null)
    : null;
  const target = options.find((o) => o.groupId === selected);
  const pick = (s: EpisodeStructureSeason) => {
    if (structure.data?.current) {
      onChange(s.seasonUnitId && s.seasonUnitId !== value ? s.seasonUnitId : "");
      return;
    }
    setAsk(s);
  };
  return (
    <div className="space-y-2">
      <StructureTrack options={options} value={selected} onChange={setPicked} />
      <div className="flex flex-wrap items-center gap-2">
        <Button
          type="button"
          size="sm"
          variant="outline"
          aria-pressed={value === ""}
          disabled={disabled}
          className={value === "" ? "pill-selected" : undefined}
          onClick={() => onChange("")}
        >
          全部季
        </Button>
        {!structure.data?.current && structure.data ? (
          <span className="text-meta text-muted-foreground">
            不是作品当前的季集结构，选季时会先确认改用「{target?.label}」
          </span>
        ) : null}
      </div>
      {structure.isPending ? (
        <LoadingState rows={2} />
      ) : structure.error ? (
        <ErrorState error={structure.error} onRetry={() => structure.refetch()} />
      ) : (
        <SeasonCardGrid
          seasons={seasons.filter((s) => s.seasonNumber > 0 || s.episodeCount > 0)}
          selected={selectedSeason}
          onPick={pick}
          disabled={disabled || setGroup.isPending}
        />
      )}
      <ConfirmDialog
        open={!!ask}
        onOpenChange={(o) => !o && setAsk(null)}
        title={`改按「${target?.label ?? DEFAULT_STRUCTURE_LABEL}」分季？`}
        description={`订阅「${ask ? seasonTitle(ask) : ""}」要先改作品设置。${switchDescription(target?.label ?? DEFAULT_STRUCTURE_LABEL)}`}
        confirmLabel="改用并选季"
        onConfirm={async () => {
          const s = ask;
          try {
            resultToast(await setGroup.mutateAsync(selected));
            setPicked(undefined);
            if (s) setAfter(s.seasonNumber);
            setAsk(null);
          } catch (err) {
            toast.error(errorMessage(err, "切换失败"));
            throw err;
          }
        }}
      />
    </div>
  );
}