import type {
  DIDResolutionOptions,
  DIDResolutionResult,
  DIDResolver,
  ParsedDID,
  Resolvable,
} from "did-resolver";

import { DID_LD_JSON, SUPPORTED_CONTENT_TYPES } from "./constants.ts";
import {
  DidResolutionError,
  RepresentationNotSupportedError,
} from "./errors/index.ts";
import { resolveDidDoc } from "./internals.ts";

/**
 * DID Resolver for Natural Persons (did:key method)
 * @returns A record mapping the "key" method with the resolver.
 */
export function getResolver(): Record<"key", DIDResolver> {
  return { key: resolve };
}

function resolve(
  did: string,
  _: ParsedDID,
  __: Resolvable,
  didResolutionOptions?: DIDResolutionOptions,
): Promise<DIDResolutionResult> {
  try {
    const contentType = didResolutionOptions?.accept ?? DID_LD_JSON;

    if (!SUPPORTED_CONTENT_TYPES.includes(contentType)) {
      throw new RepresentationNotSupportedError(
        `Representation "${contentType}" is not supported`,
      );
    }

    const didDocument = resolveDidDoc(did, contentType);

    return Promise.resolve({
      didDocument,
      didDocumentMetadata: {},
      didResolutionMetadata: { contentType },
    });
  } catch (error) {
    if (error instanceof DidResolutionError) {
      return Promise.resolve({
        // eslint-disable-next-line unicorn/no-null
        didDocument: null,
        didDocumentMetadata: {},
        didResolutionMetadata: {
          error: error.code,
          message: error.message,
        },
      });
    }

    const message = error instanceof Error ? error.message : "Unknown error";

    return Promise.resolve({
      // eslint-disable-next-line unicorn/no-null
      didDocument: null,
      didDocumentMetadata: {},
      didResolutionMetadata: {
        error: "invalidDid",
        message,
      },
    });
  }
}