import type { ApiOperation } from "../../contracts/api-operations.js";

export type OperationRequestInput = Readonly<{
  operationId: string;
  routeId: string;
  pathParams?: Readonly<Record<string, string | number>>;
  searchParams?: unknown;
  body?: unknown;
  signal?: AbortSignal;
  idempotencyKey?: string;
  correlationId?: string;
}>;

export type RequestTargetResult =
  | Readonly<{ success: true; url: URL }>
  | Readonly<{
      success: false;
      code: "PATH_PARAMETER_MISSING" | "SEARCH_PARAMETER_INVALID";
    }>;

const pathParameterPattern = /:([A-Za-z][A-Za-z0-9_]*)|\{([A-Za-z][A-Za-z0-9_]*)\}/g;

export function buildRequestTarget(
  baseUrl: string,
  operation: ApiOperation,
  pathParams: Readonly<Record<string, string | number>> = {},
  parsedSearch: unknown = {},
): RequestTargetResult {
  let missingPathParameter = false;
  const pathname = operation.path.replace(
    pathParameterPattern,
    (_token, colonName: string | undefined, braceName: string | undefined) => {
      const name = colonName ?? braceName ?? "";
      const value = pathParams[name];
      if (value === undefined) {
        missingPathParameter = true;
        return "";
      }
      return encodeURIComponent(String(value));
    },
  );
  if (missingPathParameter) {
    return { success: false, code: "PATH_PARAMETER_MISSING" };
  }

  if (
    parsedSearch === null ||
    typeof parsedSearch !== "object" ||
    Array.isArray(parsedSearch)
  ) {
    return { success: false, code: "SEARCH_PARAMETER_INVALID" };
  }

  const url = new URL(pathname, baseUrl);
  const search = parsedSearch as Readonly<Record<string, unknown>>;
  for (const key of Object.keys(search).sort((left, right) =>
    left.localeCompare(right),
  )) {
    const value = search[key];
    if (value === undefined || value === null) continue;
    const values = Array.isArray(value) ? value : [value];
    for (const item of values) {
      if (
        typeof item !== "string" &&
        typeof item !== "number" &&
        typeof item !== "boolean"
      ) {
        return { success: false, code: "SEARCH_PARAMETER_INVALID" };
      }
      url.searchParams.append(key, String(item));
    }
  }
  return { success: true, url };
}