import { type SQL, sql } from 'drizzle-orm';
import { toSnakeCase } from 'drizzle-orm/casing';
import type { AnyPgColumn } from 'drizzle-orm/pg-core';
import { customAlphabet } from 'nanoid';
import slugify from 'slugify';

const slugAlphabet = customAlphabet(
  '_-0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz',
  10,
);

export function titleToSlug(title: string) {
  const slugified = slugify(title, { lower: true });
  const slugifiedWithSuffix = `${slugified}-${slugAlphabet()}`;
  return {
    slugified,
    slugifiedWithSuffix,
  };
}

// Opaque keyset cursor: a (timestamp, id) pair, base64url encoded so callers treat it as a token instead of something they can hand-build.
export function encodeCursor({ date, id }: { date: Date; id: string }) {
  return Buffer.from(`${date.toISOString()}|${id}`).toString('base64url');
}

export function decodeCursor(cursor: string) {
  const [timestamp, id] = Buffer.from(cursor, 'base64url')
    .toString('utf8')
    .split('|');
  if (!timestamp || !id) return null;
  const date = new Date(timestamp);
  if (Number.isNaN(date.getTime())) return null;
  return { date, id };
}

// Timestamps leave the database already in the shape responses promise, so nothing downstream has to convert them. The format matches `Date.prototype.toISOString` byte for byte.
export function isoTimestamp(column: AnyPgColumn | SQL) {
  return sql<string>`to_char(${column} at time zone 'utc', 'YYYY-MM-DD"T"HH24:MI:SS.MS"Z"')`;
}

/** The value an upsert tried to insert, for `onConflictDoUpdate`. The database names columns in snake_case, however the schema spells them. */
export function excluded(column: AnyPgColumn) {
  return sql.raw(`excluded."${toSnakeCase(column.name)}"`);
}

// For `ilike`: a search for "50%" or "a_b" matches those characters, not any.
export function escapeLike(value: string) {
  return value.replace(/[\\%_]/g, (char) => `\\${char}`);
}