import { type DashboardDestination, parseModuleRoute } from "./dashboard-routes.js";

/**
 * Resolving a module's own routes (ADR 0063), free of React and browser globals.
 *
 * A module declares its primary pages; the shell opens:
 *
 * - its **root**, `/<module-id>`, which is its landing view and never itself a declared page, so no
 *   page has two addresses;
 * - each **declared page**, `/<module-id>/<page-path>`;
 * - any route **beneath** a declared page, `/<module-id>/<page-path>/…`, which the module owns —
 *   detail views (`media/sermons/123`) need no manifest entry and no sidebar entry.
 *
 * Everything else under a module is the host's `not-found`, and the module is not mounted for it:
 * an undeclared path never silently opens some other page. A module that declares no pages — every
 * manifest v8 module — has its root and nothing else, exactly as before.
 */

export interface DashboardModulePage {
  readonly id: string;
  readonly label: string;
  /** Relative to the module root: `timelines`, `media/library`. */
  readonly path: string;
}

/** Where a route lands inside its module: the declared page it is or lies beneath, `undefined` at the
 * root. `undefined` as a whole means the module has no such route. */
export interface ModuleRouteResolution {
  readonly page: DashboardModulePage | undefined;
}

export function resolveModuleRoute(
  pages: readonly DashboardModulePage[],
  path: string,
): ModuleRouteResolution | undefined {
  if (path === "") {
    return { page: undefined };
  }
  const page = pages.find(
    (candidate) => path === candidate.path || path.startsWith(`${candidate.path}/`),
  );
  return page === undefined ? undefined : { page };
}

/** `path` as one of this module's routes the shell would open, or `undefined`. Accepts the same
 * spellings `parseModuleRoute` does: an optional leading `/`, unreserved segments, no traversal. */
export function moduleRouteFor(
  pages: readonly DashboardModulePage[],
  path: unknown,
): { readonly path: string; readonly resolution: ModuleRouteResolution } | "invalid" | "unknown" {
  const route = parseModuleRoute(path);
  if (route === undefined) {
    return "invalid";
  }
  const resolution = resolveModuleRoute(pages, route);
  return resolution === undefined ? "unknown" : { path: route, resolution };
}

export function moduleDestination(moduleId: string, path = ""): DashboardDestination {
  return { kind: "module", moduleId, path };
}

const PAGE_ID_PATTERN = /^[a-z][a-z0-9]*(?:-[a-z0-9]+)*$/u;
const PAGE_PATH_SEGMENT_PATTERN = /^[a-z0-9]+(?:-[a-z0-9]+)*$/u;
const ICON_NAME_PATTERN = /^[a-z][a-z0-9]*(?:-[a-z0-9]+)*$/u;
// biome-ignore lint/suspicious/noControlCharactersInRegex: control characters are what is refused.
const CONTROL_CHARACTER_PATTERN = /[\u0000-\u001f\u007f-\u009f\u2028\u2029]/u;

/** The manifest's page grammar (`@ekklesia/contracts`), re-checked on what the server sends. */
export function isDashboardModulePage(value: unknown): value is DashboardModulePage {
  if (typeof value !== "object" || value === null || Array.isArray(value)) {
    return false;
  }
  const record = value as Record<string, unknown>;
  const keys = Object.keys(record).sort();
  if (keys.length !== 3 || keys[0] !== "id" || keys[1] !== "label" || keys[2] !== "path") {
    return false;
  }
  const { id, label, path } = record;
  return (
    typeof id === "string" &&
    id.length <= 64 &&
    PAGE_ID_PATTERN.test(id) &&
    typeof label === "string" &&
    label.trim().length > 0 &&
    label.length <= 60 &&
    !CONTROL_CHARACTER_PATTERN.test(label) &&
    typeof path === "string" &&
    path.length <= 120 &&
    path.split("/").length <= 4 &&
    path.split("/").every((segment) => PAGE_PATH_SEGMENT_PATTERN.test(segment))
  );
}

/** A syntactically valid Lucide name. Whether the Dashboard can draw it is the icon map's question:
 * a name it does not know is drawn as the generic module icon, never refused. */
export function isModuleIconName(value: unknown): value is string {
  return typeof value === "string" && value.length <= 64 && ICON_NAME_PATTERN.test(value);
}