export type FieldMap = {
  id: string;
  previewUrl: string;
  fileUrl: string;
  ext: string;
  tags: string;
  source?: string;
  rating?: string;
  score?: string;
  sampleUrl?: string;
  fileSize?: string;
  width?: string;
  height?: string;
  md5?: string;
  uploader?: string;
  createdAt?: string;
};

export type SiteConfig = {
  id: string;
  name: string;
  baseUrl: string;
  searchPath: string;
  params: { tags: string; page: string; limit: string };
  postsPath: string; // dotted path to array of posts in JSON response; "" means root
  fields: FieldMap;
  headers?: Record<string, string>;
  pageStartsAt?: number; // default 1
};

export const BUILTIN_SITES: SiteConfig[] = [
  {
    id: "e621",
    name: "e621",
    baseUrl: "https://e621.net",
    searchPath: "/posts.json",
    params: { tags: "tags", page: "page", limit: "limit" },
    postsPath: "posts",
    fields: {
      id: "id",
      previewUrl: "preview.url",
      fileUrl: "file.url",
      ext: "file.ext",
      tags: "tags.general",
      source: "sources.0",
      rating: "rating",
      score: "score.total",
      sampleUrl: "sample.url",
      fileSize: "file.size",
      width: "file.width",
      height: "file.height",
      md5: "file.md5",
      uploader: "uploader_id",
      createdAt: "created_at",
    },
    headers: { "User-Agent": "LovableGrabber/1.0 (booru client)" },
    pageStartsAt: 1,
  },
];

// Resolve a dotted path like "a.b.0.c" against an arbitrary value.
export function getByPath(obj: unknown, path: string): unknown {
  if (!path) return obj;
  const parts = path.split(".");
  let cur: unknown = obj;
  for (const p of parts) {
    if (cur == null) return undefined;
    if (Array.isArray(cur)) {
      const idx = Number(p);
      if (!Number.isInteger(idx)) return undefined;
      cur = cur[idx];
    } else if (typeof cur === "object") {
      cur = (cur as Record<string, unknown>)[p];
    } else {
      return undefined;
    }
  }
  return cur;
}

export type NormalizedPost = {
  id: string;
  previewUrl: string;
  fileUrl: string;
  ext: string;
  tags: string[];
  source?: string;
  rating?: string;
  score?: number;
  sampleUrl?: string;
  fileSize?: number;
  width?: number;
  height?: number;
  md5?: string;
  uploader?: string;
  createdAt?: string;
  rawJson?: string;
};

function optStr(v: unknown): string | undefined {
  if (v == null) return undefined;
  if (typeof v === "string") return v || undefined;
  return String(v);
}
function optNum(v: unknown): number | undefined {
  if (v == null || v === "") return undefined;
  const n = typeof v === "number" ? v : Number(v);
  return Number.isFinite(n) ? n : undefined;
}

export function normalizePost(raw: unknown, fields: FieldMap): NormalizedPost | null {
  const fileUrl = getByPath(raw, fields.fileUrl);
  const previewUrl = getByPath(raw, fields.previewUrl) ?? fileUrl;
  const id = getByPath(raw, fields.id);
  if (!fileUrl || !id) return null;

  const tagsRaw = getByPath(raw, fields.tags);
  let tags: string[] = [];
  if (Array.isArray(tagsRaw)) tags = tagsRaw.map(String);
  else if (typeof tagsRaw === "string") tags = tagsRaw.split(/\s+/).filter(Boolean);

  const extRaw = getByPath(raw, fields.ext);
  const ext =
    (typeof extRaw === "string" && extRaw) ||
    (typeof fileUrl === "string" ? (fileUrl.split(".").pop()?.split("?")[0] ?? "jpg") : "jpg");

  return {
    id: String(id),
    previewUrl: String(previewUrl),
    fileUrl: String(fileUrl),
    ext,
    tags,
    source: fields.source ? optStr(getByPath(raw, fields.source)) : undefined,
    rating: fields.rating ? optStr(getByPath(raw, fields.rating)) : undefined,
    score: fields.score ? optNum(getByPath(raw, fields.score)) : undefined,
    sampleUrl: fields.sampleUrl ? optStr(getByPath(raw, fields.sampleUrl)) : undefined,
    fileSize: fields.fileSize ? optNum(getByPath(raw, fields.fileSize)) : undefined,
    width: fields.width ? optNum(getByPath(raw, fields.width)) : undefined,
    height: fields.height ? optNum(getByPath(raw, fields.height)) : undefined,
    md5: fields.md5 ? optStr(getByPath(raw, fields.md5)) : undefined,
    uploader: fields.uploader ? optStr(getByPath(raw, fields.uploader)) : undefined,
    createdAt: fields.createdAt ? optStr(getByPath(raw, fields.createdAt)) : undefined,
    rawJson: safeStringify(raw),
  };
}

function safeStringify(v: unknown): string | undefined {
  try {
    return JSON.stringify(v);
  } catch {
    return undefined;
  }
}