/**
 * Lets a deployment configure the server through the `GERBEUR_*` environment
 * variables, which it reads once at import, and holds the fixed limits the
 * backend applies. The deno tasks load `.env` with `--env-file`, so changing a
 * setting needs a restart.
 *
 * @module
 */

import { BASE_STYLE, isStyleName, type StyleName } from "../shared/theme.ts";
import { isLocale, type Locale, SOURCE_LOCALE } from "../shared/locale.ts";

/** The port the server listens on (`GERBEUR_PORT`, default 8000). */
export const PORT: number = Number(Deno.env.get("GERBEUR_PORT")) || 8000;
/**
 * The `smtps://` URL of the server `email-service.ts` sends mail through
 * (`GERBEUR_SMTPS_URL`). When it is empty, no email is sent: sign-up sends no
 * welcome, a password reset request does nothing, and there are no digests.
 */
export const SMTPS_URL: string = Deno.env.get("GERBEUR_SMTPS_URL")?.trim() ||
  "";
/**
 * Whether the instance sends email, which is whether {@link SMTPS_URL} is
 * set. `email-service.ts` opens its transport by it, and index.html tells the
 * client, whose settings show the digest switches disabled without it.
 */
export const EMAIL_ENABLED: boolean = SMTPS_URL.length > 0;
/**
 * The `From` address of every email (`GERBEUR_FROM_EMAIL`), as an address or
 * as `Name <address>`. `email-service.ts` refuses to load without it when
 * {@link SMTPS_URL} is set.
 */
export const FROM_EMAIL: string = Deno.env.get("GERBEUR_FROM_EMAIL")?.trim() ||
  "";
/**
 * The Markdown of the welcome email sent on registration
 * (`GERBEUR_WELCOME_EMAIL_BODY`), or null for the built-in one in the
 * {@link EMAIL_LOCALE}. `api/mail/welcome.ts` replaces `{{site_name}}` and
 * `{{username}}` in it.
 */
export const WELCOME_EMAIL_BODY: string | null =
  Deno.env.get("GERBEUR_WELCOME_EMAIL_BODY")?.trim() || null;
/**
 * The language of every email (`GERBEUR_EMAIL_LOCALE`). The interface picks
 * each visitor's language in their browser, which the server never learns, so
 * the emails take the instance's. A value that isn't a locale means the
 * source one, English.
 */
export const EMAIL_LOCALE: Locale = (() => {
  const locale = Deno.env.get("GERBEUR_EMAIL_LOCALE")?.trim();
  return isLocale(locale) ? locale : SOURCE_LOCALE;
})();
/**
 * The instance's style (`GERBEUR_DEFAULT_STYLE`). The site shows it until a
 * visitor or their account picks one, through index.html, and the emails that
 * aren't a user's own (the welcome and the password reset) are drawn in it. A
 * value that isn't a style means {@link BASE_STYLE}.
 */
export const DEFAULT_STYLE: StyleName = (() => {
  const style = Deno.env.get("GERBEUR_DEFAULT_STYLE")?.trim();
  return isStyleName(style) ? style : BASE_STYLE;
})();
/**
 * The key lib/jwt.ts signs and verifies tokens with (`GERBEUR_JWT_SECRET`).
 * The server refuses to start without it.
 */
export const JWT_SECRET: string = Deno.env.get("GERBEUR_JWT_SECRET")?.trim() ||
  "";
/**
 * The interface the server binds to (`GERBEUR_LISTEN_HOST`). The default,
 * 0.0.0.0, lets Docker forward the port; 127.0.0.1 keeps it to loopback.
 */
export const LISTEN_HOST: string = Deno.env.get("GERBEUR_LISTEN_HOST") ||
  "0.0.0.0";
/**
 * The URL visitors reach the server at (`GERBEUR_PUBLIC_URL`), without a
 * trailing slash. Behind a reverse proxy it must be the outside URL: it is an
 * allowed origin, it tells links to this site's own pages from other links,
 * and it prefixes the image URLs in their previews.
 */
export const PUBLIC_URL: string =
  Deno.env.get("GERBEUR_PUBLIC_URL")?.trim().replace(/\/$/, "") ||
  `http://localhost:${PORT}`;
/**
 * Points password reset links and the Open Graph tags' page URLs at the
 * frontend when it isn't served from {@link PUBLIC_URL}, as with a separate
 * Vite server, and allows it as an origin. It is `GERBEUR_FRONTEND_URL`,
 * without a trailing slash.
 */
export const FRONTEND_URL: string =
  Deno.env.get("GERBEUR_FRONTEND_URL")?.trim().replace(/\/$/, "") ||
  PUBLIC_URL;
/**
 * The SQLite database file (`GERBEUR_DB_PATH`). api/test/setup.ts points it at
 * a throwaway file before anything opens the database.
 */
export const DB_PATH: string = Deno.env.get("GERBEUR_DB_PATH") ||
  "api/sql/gerbeur.db";

/**
 * The directory uploads are stored under (`GERBEUR_UPLOADS_DIR`). Each kind has
 * its subdirectory below, created by the first upload, and each file is named
 * after the id of what it belongs to.
 */
export const UPLOADS_DIR: string = Deno.env.get("GERBEUR_UPLOADS_DIR") ||
  "api/uploads";
/** Holds the file of each file dump. */
export const DUMPS_DIR = `${UPLOADS_DIR}/dumps`;
/** Holds each user's avatar. */
export const AVATARS_DIR = `${UPLOADS_DIR}/avatars`;
/** Holds each playlist's cover. */
export const PLAYLIST_IMAGES_DIR = `${UPLOADS_DIR}/playlist-images`;
/**
 * Holds the images pasted into chat messages, comments, dump notes and
 * descriptions. The startup tasks purge those nothing links to.
 */
export const ATTACHMENTS_DIR = `${UPLOADS_DIR}/attachments`;
/**
 * Holds the thumbnails a poster uploads (`<id>-custom`) and those the
 * thumbnails route generates from file dumps.
 */
export const THUMBNAILS_DIR = `${UPLOADS_DIR}/thumbnails`;
/**
 * Holds the scaled-down copies of the images above, which lib/ffmpeg.ts makes
 * as they are first asked for, each at its upload's path with its width. It
 * can be emptied at any time: the copies are made again.
 */
export const SCALED_DIR = `${UPLOADS_DIR}/scaled`;

/**
 * Caps the size of an image upload, in bytes, for avatars, covers, thumbnails
 * and attachments. lib/upload.ts states it in megabytes in its error.
 */
export const MAX_IMAGE_SIZE_BYTES = 5 * 1024 * 1024;

/**
 * The MIME type prefixes a file dump may have. dump-service also accepts the
 * exact types of {@link DUMP_ALLOWED_MIME_TYPES}.
 */
export const DUMP_ALLOWED_MIME_PREFIXES: string[] = [
  "text/",
  "image/",
  "video/",
  "audio/",
];
/** The documents and archives a file dump may be, beyond the prefixes. */
export const DUMP_ALLOWED_MIME_TYPES: Set<string> = new Set([
  "application/pdf",
  "application/json",
  "application/zip",
  "application/x-zip-compressed",
  "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
  "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
  "application/vnd.openxmlformats-officedocument.presentationml.presentation",
  "application/msword",
  "application/vnd.ms-excel",
  "application/vnd.ms-powerpoint",
]);

/** The page size when a request names none. */
export const PAGINATION_DEFAULT_LIMIT = 20;
/** The largest page size a request may ask for. */
export const PAGINATION_MAX_LIMIT = 100;

/** How long an attachment nothing links to is kept before startup purges it. */
export const ORPHANED_ATTACHMENTS_RETENTION_HOURS = 1;
/**
 * How long an invite stays usable. invite-service refuses an older one, and
 * the startup tasks purge it.
 */
export const UNUSED_INVITES_RETENTION_DAYS = 7;

/**
 * How often, in minutes, the `/community` page's figures are recomputed
 * (`GERBEUR_COMMUNITY_REFRESH_MINUTES`), 15 by default.
 */
export const COMMUNITY_REFRESH_MINUTES: number =
  Number(Deno.env.get("GERBEUR_COMMUNITY_REFRESH_MINUTES")) || 15;

/**
 * The site's name (`GERBEUR_SITE_NAME`). It is filled into index.html, the OG
 * tags, the icons' manifest and the emails.
 */
export const OG_SITE_NAME: string = Deno.env.get("GERBEUR_SITE_NAME") ||
  "gerbeur";

/**
 * The emoji that serves as the site's logo (`GERBEUR_SITE_EMOJI`). The icons
 * script draws the favicons from it, and index.html carries it to the app's
 * header, so changing it needs a restart but no rebuild.
 */
export const SITE_EMOJI: string = Deno.env.get("GERBEUR_SITE_EMOJI") || "🚚";

/**
 * How the frontend plays Bandcamp. `"embed"` uses Bandcamp's iframe, which
 * can't autoplay. `"native"` resolves the page's streams through
 * `GET /api/bandcamp/tracks` and plays them in the app's player, which
 * autoplays and queues an album's tracks.
 */
export type BandcampPlayer = "embed" | "native";
/**
 * How the frontend plays Bandcamp (`GERBEUR_BANDCAMP_PLAYER`), passed to it in
 * index.html. Any value but `"native"` means `"embed"`, so a typo falls back to
 * the player that always works.
 */
export const BANDCAMP_PLAYER: BandcampPlayer =
  Deno.env.get("GERBEUR_BANDCAMP_PLAYER")?.trim() === "native"
    ? "native"
    : "embed";

/**
 * The background of the generated Apple touch icon, the manifest's colors, and
 * the accent of previews of this site's own pages. index.html's `theme-color`
 * tags don't follow it.
 */
export const THEME_COLOR = "#111827";

const rawOrigins = Deno.env.get("GERBEUR_ALLOWED_ORIGINS") ?? "";
/**
 * The origins that CORS in main.ts and the WebSocket route accept. They are
 * {@link PUBLIC_URL}, {@link FRONTEND_URL} and the comma-separated
 * `GERBEUR_ALLOWED_ORIGINS`.
 */
export const ALLOWED_ORIGINS: string[] = Array.from(
  new Set([
    PUBLIC_URL,
    FRONTEND_URL,
    ...rawOrigins.split(",").map((o) => o.trim()).filter(Boolean),
  ]),
);

/**
 * Lets federated sign-in reach instances on private addresses, `localhost`
 * among them, and over plain http (`GERBEUR_FEDERATION_ALLOW_PRIVATE=1`), so
 * that two instances on one machine can trust each other in development.
 * Off, `remote/gerbeur-instance.ts` reaches only public https instances, since
 * an identity is only as safe as the connection it came over.
 */
export const FEDERATION_ALLOW_PRIVATE: boolean =
  Deno.env.get("GERBEUR_FEDERATION_ALLOW_PRIVATE")?.trim() === "1";
/**
 * Which ways federated sign-in goes, each on unless set to `0`.
 *
 * - `incoming` (`GERBEUR_FEDERATION_INCOMING`): users of other instances sign
 *   in here. Off, the login and register pages offer no other instance,
 *   `/manage` lists only the blocked ones, which this instance's users can't
 *   sign in to (and none with `outgoing` off too), `federation-service.ts`
 *   refuses their sign-ins, and the accounts that came from one are signed
 *   out (`getSessionState`) until it is on again. Their homes' events are
 *   still applied, so that none is lost meanwhile.
 * - `outgoing` (`GERBEUR_FEDERATION_OUTGOING`): this instance's users sign in
 *   to others. Off, `identity-provider-service.ts` lets no instance sign them
 *   in, and its metadata says so, which the others check before sending
 *   anyone here to sign in. The settings page lists no instances, since at
 *   startup `main.ts` withdraws every grant they gave, which signs them out
 *   there.
 *
 * index.html tells the client both. An object, so that the tests can turn one
 * off for a while.
 */
export const FEDERATION: { incoming: boolean; outgoing: boolean } = {
  incoming: Deno.env.get("GERBEUR_FEDERATION_INCOMING")?.trim() !== "0",
  outgoing: Deno.env.get("GERBEUR_FEDERATION_OUTGOING")?.trim() !== "0",
};