import { formatServiceError, isAbortError } from "../shared/errors";
import { fetchJson, fetchText } from "../shared/http";
import { CONTEXT7_API_BASE, type LibraryResult, type LibrarySearchResponse } from "../types";

function buildContext7Headers(apiKey: string | null): Record<string, string> {
  const headers: Record<string, string> = { "Content-Type": "application/json" };
  if (apiKey) headers.Authorization = `Bearer ${apiKey}`;
  return headers;
}

/**
 * Resolves a user-supplied library/query pair to the first Context7 library match.
 * Returns `{ id, name }` on success or `{ error }` for provider/HTTP failures; abort errors are rethrown.
 * Accepts both array and `{ results }` response shapes and falls back from `name` to `title` to `id`.
 */
export async function resolveContext7Library(library: string, query: string, apiKey: string | null, signal?: AbortSignal): Promise<{ id: string; name: string } | { error: string }> {
  try {
    const params = new URLSearchParams({ libraryName: library, query });
    const data = await fetchJson<LibraryResult[] | LibrarySearchResponse>(`${CONTEXT7_API_BASE}/libs/search?${params}`, {
      headers: buildContext7Headers(apiKey),
      signal,
    });

    const results = Array.isArray(data) ? data : (data.results ?? []);
    if (!results.length) {
      return { error: `No library found matching \"${library}\"` };
    }

    const first = results[0];
    return { id: first.id, name: first.name ?? first.title ?? first.id };
  } catch (error) {
    if (isAbortError(error)) throw error;
    return { error: `Library search failed: ${formatServiceError("Context7", error)}` };
  }
}

/**
 * Fetches documentation content for a resolved Context7 library id and query.
 * Returns `{ content }` on success or `{ error }` for provider/HTTP failures; abort errors are rethrown.
 * Sends the already-resolved id unchanged and leaves snippet/query normalization to Context7.
 */
export async function fetchContext7Docs(libraryId: string, query: string, apiKey: string | null, signal?: AbortSignal): Promise<{ content: string } | { error: string }> {
  try {
    const params = new URLSearchParams({ libraryId, query });
    const content = await fetchText(`${CONTEXT7_API_BASE}/context?${params}`, {
      headers: buildContext7Headers(apiKey),
      signal,
    });
    return { content };
  } catch (error) {
    if (isAbortError(error)) throw error;
    return { error: `Docs fetch failed: ${formatServiceError("Context7", error)}` };
  }
}