import type {
  AssetVersion,
  DownloadSavePaths,
  DownloadSaveTarget,
  LibraryVersions,
  ManualAcquisitionRequest,
  VersionSummary,
} from "@umt/contracts";
import { formatBytes } from "~/lib/utils.ts";

// 手动下载对话框的纯逻辑:保存目录解析、已有版本摘要、提交参数。界面在 manual-download-dialog.tsx。

export type ManualDownloadOptions = Omit<ManualAcquisitionRequest, "sourceReleaseId">;
export type TmdbType = "movie" | "tv";

/** 保存目录下拉的取值:"" = 自动,CUSTOM_DIR = 自定义路径,其余是目录本身 */
export const CUSTOM_DIR = "__custom__";

/** 选中的下载器;没选时用「自动」会用的那个 */
export function targetOf(paths: DownloadSavePaths | undefined, instanceId: string): DownloadSaveTarget | null {
  if (!paths) return null;
  const id = instanceId || paths.autoInstanceId;
  return paths.instances.find((t) => t.instanceId === id) ?? null;
}

/** 「将保存到」显示的路径:自动 = 下载器默认保存目录;自定义取输入框;没有可用下载器为 null */
export function resolveSavePath(
  target: DownloadSaveTarget | null,
  dir: string,
  custom: string,
): { path: string; hostPath: string | null } | null {
  if (dir === CUSTOM_DIR) {
    const p = custom.trim();
    return p ? { path: p, hostPath: null } : null;
  }
  if (!target) return null;
  const hit = dir ? target.dirs.find((d) => d.path === dir) : target.dirs[0];
  return hit ? { path: hit.path, hostPath: hit.hostPath } : null;
}

/** 本机路径与下载器路径不同时括注本机路径,方便对照文件管理 */
export function savePathText(r: { path: string; hostPath: string | null }): string {
  return r.hostPath && r.hostPath !== r.path ? `${r.path}（本机 ${r.hostPath}）` : r.path;
}

/** 已有版本去重展开(电影 / 每集 / 未对上集的) */
export function existingVersions(inv: LibraryVersions | undefined): AssetVersion[] {
  const out = new Map<string, AssetVersion>();
  for (const v of inv?.movie?.versions ?? []) out.set(v.assetId, v);
  for (const season of inv?.seasons ?? [])
    for (const episode of season.episodes) for (const v of episode.versions) out.set(v.assetId, v);
  for (const v of inv?.unplaced ?? []) out.set(v.assetId, v);
  return [...out.values()];
}

/** 一行摘要:「媒体库已有：1080p WEB-DL · 8.9 GB」;多种规格只列前两种 */
export function versionSummaryText(s: VersionSummary | undefined): string | null {
  if (!s?.versionCount) return null;
  const specs = s.specs.map((g) => [g.resolution, g.source, ...g.hdr].filter(Boolean).join(" ")).filter(Boolean);
  const head = specs.slice(0, 2).join("、") + (specs.length > 2 ? ` 等 ${specs.length} 种` : "");
  const parts = [
    head,
    s.versionCount > 1 ? `${s.versionCount} 个版本` : "",
    s.sizeBytes ? formatBytes(s.sizeBytes, 1) : "",
  ];
  return `媒体库已有：${parts.filter(Boolean).join(" · ")}`;
}

/** 下载前指定的作品:本地作品,或按类型 + TMDB 编号 */
export type IdentityChoice =
  | { kind: "entity"; id: string; title: string }
  | { kind: "tmdb"; type: TmdbType; id: string };

/** 作品当前的 TMDB 身份;和它相同就不算改动 */
export function identityChanged(
  choice: IdentityChoice | null,
  current: { entityId?: string | undefined; tmdb?: { type: TmdbType; id: string } | null },
): boolean {
  if (!choice) return false;
  if (choice.kind === "entity") return choice.id !== current.entityId;
  if (!/^\d+$/.test(choice.id)) return false;
  return !(current.tmdb && current.tmdb.type === choice.type && current.tmdb.id === choice.id);
}

export function buildManualOptions(s: {
  entityId?: string | undefined;
  currentTmdb?: { type: TmdbType; id: string } | null;
  identity: IdentityChoice | null;
  instanceId: string;
  target: DownloadSaveTarget | null;
  dir: string;
  custom: string;
  allowUnrecognized: boolean;
  mode: "normal" | "replace";
  selected: string[];
}): ManualDownloadOptions {
  const changed = identityChanged(s.identity, { entityId: s.entityId, tmdb: s.currentTmdb ?? null });
  const identity: ManualDownloadOptions["identity"] =
    changed && s.identity
      ? s.identity.kind === "entity"
        ? { mediaEntityId: s.identity.id }
        : { external: { provider: "tmdb", entityType: s.identity.type, externalId: s.identity.id } }
      : undefined;
  // 改了作品时已有版本属于旧作品,只能正常入库
  const mode = identity ? "normal" : s.mode;
  const savePath = s.dir === CUSTOM_DIR ? s.custom.trim() : s.dir;
  // 自动下载器 + 指定目录:钉住解析出的那个下载器,目录才对得上
  const instanceId = s.instanceId || (savePath && s.dir !== CUSTOM_DIR ? (s.target?.instanceId ?? "") : "");
  return {
    ...(identity ? { identity } : s.entityId ? { entityId: s.entityId } : {}),
    ...(instanceId ? { downloaderInstanceId: instanceId } : {}),
    ...(savePath ? { savePath } : {}),
    ...(s.allowUnrecognized && !identity ? { allowUnrecognized: true } : {}),
    importMode: mode,
    replacementAssetIds: mode === "replace" ? s.selected : [],
  };
}

/** 从标题解析结果猜类型:有季或集就是剧集 */
export function kindHintOf(parsed: unknown): TmdbType {
  const p = (parsed ?? {}) as { season?: unknown; episodes?: unknown };
  return (p.season !== undefined && p.season !== null) || (p.episodes !== undefined && p.episodes !== null)
    ? "tv"
    : "movie";
}

/** 作品类型 → TMDB 类型 */
export const tmdbTypeOf = (kind: string | undefined): TmdbType => (kind === "movie" ? "movie" : "tv");