import { confidenceOf, parseRelease } from "./parse.ts";
import type { Confidence, PackHint, ParsedRelease, ParseOptions } from "./types.ts";

export interface PathSegments {
  file: string;
  parent?: string;
  grandParent?: string;
}

const EXTRAS_DIR =
  /^(?:featurettes?|extras?|bonus(?:es)?|behind[ ._-]the[ ._-]scenes|deleted[ ._-]scenes|interviews?|trailers?|shorts|scenes|花絮|特典|特辑|特輯|幕后|幕後)$/iu;
const SAMPLE_DIR = /^samples?$/i;

/** 把路径拆成 文件 / 父目录 / 祖父目录;附加内容目录会被跳过并记为 extra */
export function splitReleasePath(path: string): PathSegments & { extrasDir?: string; sampleDir?: boolean } {
  const parts = path.split(/[\\/]+/).filter((p) => p.length > 0);
  const file = parts.pop() ?? "";
  let parent = parts.pop();
  let extrasDir: string | undefined;
  let sampleDir = false;
  if (parent && (EXTRAS_DIR.test(parent) || SAMPLE_DIR.test(parent))) {
    if (SAMPLE_DIR.test(parent)) sampleDir = true;
    else extrasDir = parent;
    parent = parts.pop();
  }
  const grandParent = parts.pop();
  return {
    file,
    ...(parent !== undefined ? { parent } : {}),
    ...(grandParent !== undefined ? { grandParent } : {}),
    ...(extrasDir ? { extrasDir } : {}),
    ...(sampleDir ? { sampleDir } : {}),
  };
}

/** 合并后的置信度:由证据推导,多次合并不会把降级"洗掉" */
function mergedConfidence(r: ParsedRelease): Confidence {
  let conf = confidenceOf(r);
  if (r.evidence.some((e) => /_dir:/.test(e))) conf = minConfidence(conf, "multi_evidence");
  if (r.evidence.some((e) => e.endsWith(":type_inferred"))) conf = "needs_confirm";
  if (r.mediaTypeHint !== "tv" && r.evidence.some((e) => e.endsWith(":conflict_year"))) conf = "needs_confirm";
  return conf;
}

const RANK: Record<Confidence, number> = { rule_confirmed: 2, multi_evidence: 1, needs_confirm: 0 };
const minConfidence = (a: Confidence, b: Confidence): Confidence => (RANK[a] <= RANK[b] ? a : b);

function filePackHint(r: ParsedRelease): PackHint {
  if (r.airDate !== undefined || r.issue !== undefined) return "single";
  if (r.episodes) return r.episodes.end > r.episodes.start ? "multi_episode" : "single";
  return r.mediaTypeHint === "tv" ? "unknown" : "single";
}

/**
 * 文件优先、上级目录只补空字段(对照 MP MetaInfoPath.merge)。
 * 偏离:文件本身无剧集信号而目录是剧集时,MP 不合并;本项目合并名称与季号,
 * 打 `<level>:type_inferred` 证据并把置信度降为 needs_confirm。
 */
export function mergeParsed(
  primary: ParsedRelease,
  fallback: ParsedRelease,
  level: "parent_dir" | "grandparent_dir",
): ParsedRelease {
  const r: ParsedRelease = {
    ...primary,
    audio: [...primary.audio],
    hdr: [...primary.hdr],
    variantTags: [...primary.variantTags],
    evidence: [...primary.evidence],
  };
  const used: string[] = [];
  // 目录只有日期(`…Collection.20240501.FRDS` 这类收藏/打包日期)不算剧集信号,不参与类型合并
  const dateOnly =
    fallback.airDate !== undefined &&
    fallback.season === undefined &&
    fallback.episodes === undefined &&
    fallback.issue === undefined &&
    fallback.totalEpisodes === undefined;
  const fbTv = fallback.mediaTypeHint === "tv" && !dateOnly;
  const deviation = primary.mediaTypeHint !== "tv" && fbTv;

  if (!primary.title) {
    if (fallback.title) {
      r.title = fallback.title;
      r.titleCn = fallback.titleCn;
      r.titleEn = fallback.titleEn;
      used.push("title");
    }
  }
  if (r.year === undefined && fallback.year !== undefined) {
    r.year = fallback.year;
    used.push("year");
  }
  if ((r.season === undefined || r.seasonInferred) && fallback.season !== undefined && !fallback.seasonInferred) {
    r.season = fallback.season;
    r.seasonInferred = undefined;
    if (!r.isFile && fallback.seasonEnd !== undefined) r.seasonEnd = fallback.seasonEnd;
    used.push("season");
  }
  const fill = <K extends keyof ParsedRelease>(k: K) => {
    if (r[k] === undefined && fallback[k] !== undefined) {
      r[k] = fallback[k];
      used.push(String(k));
    }
  };
  for (const k of [
    "resolution",
    "source",
    "videoCodec",
    "encoder",
    "bitDepth",
    "releaseGroup",
    "cut",
    "webSource",
    "uhd",
    "fps",
    "subtitles",
  ] as const)
    fill(k);
  if (used.includes("source")) r.isEncode = fallback.isEncode;
  if (r.audio.length === 0 && fallback.audio.length > 0) {
    r.audio = [...fallback.audio];
    used.push("audio");
  }
  if (r.hdr.length === 0 && fallback.hdr.length > 0) {
    r.hdr = [...fallback.hdr];
    used.push("hdr");
  }
  if (r.explicitIds.length === 0 && fallback.explicitIds.length > 0) {
    r.explicitIds = [...fallback.explicitIds];
    used.push("explicitIds");
  }
  if (r.contentType === "unknown" && fallback.contentType !== "unknown") {
    r.contentType = fallback.contentType;
    used.push("contentType");
  }
  if (fbTv) r.mediaTypeHint = "tv";
  for (const u of used) r.evidence.push(`${level}:${u}`);

  if (r.isFile) {
    r.packHint = filePackHint(r);
    r.isSeasonPack = false;
  }
  if (deviation && used.length > 0) r.evidence.push(`${level}:type_inferred`);
  if (primary.year !== undefined && fallback.year !== undefined && primary.year !== fallback.year) {
    // 电影合集年份冲突:以文件为准,但需要确认
    r.evidence.push(`${level}:conflict_year`);
  }
  r.confidence = mergedConfidence(r);
  return r;
}

/**
 * 目录名 + 文件名合并识别。纯函数,不访问文件系统;最多看两级上级目录。
 * 附加内容目录(Featurettes/Extras/花絮…)不参与命名,结果标记 contentType=extra。
 */
export function parseReleasePath(path: string | PathSegments, opts: ParseOptions = {}): ParsedRelease {
  const seg = typeof path === "string" ? splitReleasePath(path) : path;
  const { subtitle: _subtitle, ...dirOpts } = opts;
  let r = parseRelease(seg.file, { ...opts, isFile: true });
  if (seg.parent) r = mergeParsed(r, parseRelease(seg.parent, { ...dirOpts, isFile: false }), "parent_dir");
  if (seg.grandParent)
    r = mergeParsed(r, parseRelease(seg.grandParent, { ...dirOpts, isFile: false }), "grandparent_dir");
  const extras = typeof path === "string" ? splitReleasePath(path) : undefined;
  if (extras?.extrasDir && seg.parent) {
    // 附加内容归属父作品:名称取父目录,文件自身名称不参与身份识别
    const owner = parseRelease(seg.parent, { ...dirOpts, isFile: false });
    r.title = owner.title;
    r.titleCn = owner.titleCn;
    r.titleEn = owner.titleEn;
    r.contentType = "extra";
    r.evidence.push("dir:extras");
    r.confidence = "needs_confirm";
  }
  if (extras?.sampleDir) r.evidence.push("dir:sample");
  return r;
}