import { extname } from "node:path";
import type { FilesSuggestNameRequest, FilesSuggestNameResult } from "@umt/contracts";
import { buildNamingVars, normalizeTitle, parseReleasePath, renderNamingPath } from "@umt/domain";
import { effectiveNaming, loadNamingEntity } from "../acquisition-organize/services/naming.ts";
import { FilesError, type FmDeps, resolveIn } from "./common.ts";

// G9 推荐名:按命名模板(作品 > 库根 > 全局)对选中文件/目录渲染名字(与整理用同一引擎与变量来源)。
// 作品:请求指定 > 已登记资产所属 > 解析标题在本地别名里唯一精确命中;都没有 → name=null, reason=identity_uncertain。
// 文件给文件名段;目录按解析结果给季目录段(只有季号)或作品目录段。

const empty = (reason: string, mediaEntityId: string | null = null): FilesSuggestNameResult => ({
  name: null,
  relativePath: null,
  reason,
  mediaEntityId,
  templateSource: null,
  segments: [],
});

function segmentsOf(rel: string) {
  const parts = rel.split("/");
  const file = parts.pop()!;
  const parent = parts.pop();
  const grandParent = parts.pop();
  return { file, ...(parent ? { parent } : {}), ...(grandParent ? { grandParent } : {}) };
}

export async function suggestName(d: FmDeps, body: FilesSuggestNameRequest): Promise<FilesSuggestNameResult> {
  const db = d.ctx.db;
  const r = await resolveIn(d, body.root, body.path);
  if (r.rel === "") throw new FilesError("bad_request", "不能给登记目录本身生成推荐名");
  const isDir = !!r.lst?.isDirectory();
  const parsed = parseReleasePath(segmentsOf(r.rel));

  let entityId = body.mediaEntityId ?? null;
  if (!entityId && r.def.libraryRootId) {
    const row = await db
      .selectFrom("asset_location as l")
      .innerJoin("media_asset as a", "a.id", "l.media_asset_id")
      .select(["a.media_entity_id"])
      .where("l.library_root_id", "=", r.def.libraryRootId)
      .where("l.status", "<>", "removed")
      .where((eb) =>
        isDir
          ? eb("l.relative_path", "like", `${r.rel.replace(/[\\%_]/g, (m) => `\\${m}`)}/%`)
          : eb("l.relative_path", "=", r.rel),
      )
      .executeTakeFirst();
    entityId = row?.media_entity_id ?? null;
  }
  if (!entityId && parsed.title) {
    const n = normalizeTitle(parsed.title);
    const hits = n
      ? await db
          .selectFrom("title_alias as a")
          .innerJoin("media_entity as e", "e.id", "a.media_entity_id")
          .select(["e.id", "e.year"])
          .distinct()
          .where("a.normalized", "=", n)
          .where("e.status", "not in", ["merged", "archived"])
          .limit(5)
          .execute()
      : [];
    const byYear = parsed.year ? hits.filter((h) => h.year === parsed.year) : hits;
    if (byYear.length === 1) entityId = byYear[0]!.id;
  }
  if (!entityId) return empty("identity_uncertain");

  const entity = await db.selectFrom("media_entity").selectAll().where("id", "=", entityId).executeTakeFirst();
  if (!entity) throw new FilesError("not_found", "作品不存在");
  const root = r.def.libraryRootId
    ? await db.selectFrom("library_root").selectAll().where("id", "=", r.def.libraryRootId).executeTakeFirst()
    : undefined;
  const namingSettings = await d.ctx.settings.get("naming").catch(() => undefined);
  const eff = effectiveNaming(namingSettings, root ?? null, entity);
  const namingEntity = await loadNamingEntity(db, entity, { libraryRoot: root?.name });
  const kind = namingEntity.kind ?? "movie";
  const ext = isDir ? "" : extname(r.rel);
  const vars = buildNamingVars(namingEntity, parsed, isDir ? {} : { fileExt: ext });
  const out = renderNamingPath(eff.templates[kind], vars, isDir ? { mode: "dirs" } : {});
  const segments = out.segments.map((s) => ({ text: s.text, role: s.role }));
  if (!out.ok)
    return {
      ...empty(`naming_failed: ${out.errors.map((e) => e.message).join("; ")}`, entityId),
      templateSource: eff.sources[kind],
      segments,
    };
  const want = isDir ? (parsed.season !== undefined && !parsed.episodes ? "season" : "root") : "file";
  const seg = out.segments.find((s) => s.role === want);
  return {
    name: seg?.text || null,
    relativePath: out.relativePath,
    reason: seg?.text ? null : `no_${want}_segment`,
    mediaEntityId: entityId,
    templateSource: eff.sources[kind],
    segments,
  };
}