/* Pure helpers shared by the editor (client) and the API (server). */
import type { GalleryImage, PostInput } from "./types";

export const SLUG_RE = /^[a-z0-9]+(?:-[a-z0-9]+)*$/;
export const DATE_RE = /^\d{4}-\d{2}-\d{2}$/;

/** "Hello, World!" -> "hello-world" */
export function slugify(text: string): string {
  return text
    .toLowerCase()
    .normalize("NFKD")
    .replace(/[̀-ͯ]/g, "")
    .replace(/[^a-z0-9]+/g, "-")
    .replace(/^-+|-+$/g, "");
}

/** Same as categoryLabel() in portfolio/data/content.ts. */
export function categoryLabel(slug: string): string {
  return slug
    .split(/[-_]+/)
    .filter(Boolean)
    .map((word) => word.charAt(0).toUpperCase() + word.slice(1))
    .join(" ");
}

/** Trim, drop empties, dedupe case-insensitively (first spelling wins). */
export function normalizeTags(tags: string[]): string[] {
  const seen = new Set<string>();
  const out: string[] = [];
  for (const raw of tags) {
    const tag = raw.trim();
    const key = tag.toLowerCase();
    if (!tag || seen.has(key)) continue;
    seen.add(key);
    out.push(tag);
  }
  return out;
}

export function todayIso(): string {
  const d = new Date();
  const pad = (n: number) => String(n).padStart(2, "0");
  return `${d.getFullYear()}-${pad(d.getMonth() + 1)}-${pad(d.getDate())}`;
}

function cleanImage(raw: unknown): GalleryImage | null {
  const obj = typeof raw === "object" && raw !== null ? (raw as Record<string, unknown>) : null;
  const src = typeof raw === "string" ? raw : obj?.src;
  if (typeof src !== "string") return null;
  const cleaned = src.trim().replace(/^\/+/, "");
  if (!cleaned || cleaned.split("/").includes("..")) return null;
  const description = typeof obj?.description === "string" ? obj.description.trim() : "";
  return description ? { src: cleaned, description } : cleaned;
}

/** Validates and normalizes an editor submission. */
export function validatePost(raw: unknown): { post: PostInput | null; errors: string[] } {
  const errors: string[] = [];
  const r = (raw ?? {}) as Record<string, unknown>;
  const str = (key: string) => (typeof r[key] === "string" ? (r[key] as string).trim() : "");

  const slug = str("slug");
  const title = str("title");
  const description = str("description");
  const date = str("date");
  const category = str("category");
  const details = typeof r.details === "string" ? r.details : "";

  if (!SLUG_RE.test(slug)) errors.push("slug must be lowercase kebab-case (a-z, 0-9, -)");
  if (!title) errors.push("title is required");
  if (!description) errors.push("description is required");
  if (!DATE_RE.test(date) || Number.isNaN(Date.parse(date))) errors.push("date must be YYYY-MM-DD");
  if (!SLUG_RE.test(category)) errors.push("category must be lowercase kebab-case");
  if (!Array.isArray(r.tags) || r.tags.some((t) => typeof t !== "string")) {
    errors.push("tags must be a list of strings");
  }

  const images: GalleryImage[] = [];
  if (r.images !== undefined) {
    if (!Array.isArray(r.images)) errors.push("images must be a list");
    else
      for (const item of r.images) {
        const img = cleanImage(item);
        if (img) images.push(img);
        else errors.push("images contains an invalid path");
      }
  }

  if (errors.length) return { post: null, errors };
  return {
    post: {
      slug,
      title,
      description,
      date,
      category,
      tags: normalizeTags(r.tags as string[]),
      ...(images.length ? { images } : {}),
      details: !details || details.endsWith("\n") ? details : details + "\n",
    },
    errors,
  };
}