import { Effect } from "effect";

import type { SpecFormatAdapter } from "../../sdk/spec-format";

import { buildMicrosoftGraphOpenApiSpec, microsoftGraphKeepPathItem } from "./graph";
import { microsoftGraphPresetIdsForSliceAsset, microsoftGraphSliceAssetFromUrl } from "./slices";

const fragmentPresetIds = (hash: string): readonly string[] =>
  hash.startsWith("#preset=")
    ? decodeURIComponent(hash.slice("#preset=".length))
        .split(",")
        .map((presetId) => presetId.trim())
        .filter((presetId) => presetId.length > 0)
    : [];

/**
 * Selection from a catalog URL. A slice URL is the byte source itself: its
 * asset carries the selection, and a fragment may narrow within the asset.
 * Any other URL (the upstream monolith, an emulator override) is fetched as
 * given, with the fragment as the selection filter.
 */
const graphCatalogSelection = (
  rawUrl: string | undefined,
): { readonly specUrl?: string; readonly presetIds?: readonly string[] } => {
  if (!rawUrl || !URL.canParse(rawUrl)) return rawUrl ? { specUrl: rawUrl } : {};
  const parsed = new URL(rawUrl);
  const fromFragment = fragmentPresetIds(parsed.hash);
  parsed.hash = "";
  const specUrl = parsed.toString();
  const sliceAsset = microsoftGraphSliceAssetFromUrl(specUrl);
  const presetIds =
    fromFragment.length > 0
      ? fromFragment
      : sliceAsset !== null
        ? (microsoftGraphPresetIdsForSliceAsset(sliceAsset) ?? [])
        : [];
  return {
    specUrl,
    ...(presetIds.length > 0 ? { presetIds } : {}),
  };
};

export const microsoftGraphAdapter: SpecFormatAdapter = {
  id: "microsoft-graph",
  fetch: (input) =>
    buildMicrosoftGraphOpenApiSpec(
      graphCatalogSelection(input.urls[0]),
      input.httpClientLayer,
    ).pipe(
      Effect.map((graphSpec) => ({
        specText: graphSpec.specText,
        specUrl: graphSpec.specUrl,
        baseUrl: graphSpec.baseUrl,
        authenticationTemplate: graphSpec.authenticationTemplate,
        // Stream the full Graph source straight to persisted bindings. This is
        // the measured Workers contention/OOM path from the Microsoft plugin:
        // structural split stays serial and avoids materializing the 37MB tree.
        keepPathItem: microsoftGraphKeepPathItem(graphSpec),
        config: {
          microsoftGraphPresetIds: graphSpec.presetIds,
          microsoftGraphCustomScopes: graphSpec.customScopes,
          microsoftGraphScopes: graphSpec.scopes,
          microsoftGraphExactPaths: graphSpec.exactPaths,
          microsoftGraphPathPrefixes: graphSpec.pathPrefixes,
          microsoftGraphTagPrefixes: graphSpec.tagPrefixes,
          microsoftGraphCoversFullGraph: graphSpec.coversFullGraph,
          microsoftGraphAuthorizationUrl: graphSpec.authorizationUrl,
          microsoftGraphTokenUrl: graphSpec.tokenUrl,
          microsoftGraphClientCredentialsTokenUrl: graphSpec.clientCredentialsTokenUrl,
        },
      })),
    ),
};