import {
  getProviderCredentials,
  markAccountUnavailable,
  clearAccountError,
  extractApiKey,
  isValidApiKey,
} from "../services/auth.js";
import { getSettings } from "@/lib/localDb";
import { getModelInfo } from "../services/model.js";
import { handleImageGenerationCore } from "open-sse/handlers/imageGenerationCore.js";
import { errorResponse, unavailableResponse } from "open-sse/utils/error.js";
import { HTTP_STATUS } from "open-sse/config/runtimeConfig.js";
import { updateProviderCredentials, checkAndRefreshToken } from "../services/tokenRefresh.js";

// Providers that don't require credentials (noAuth)
const NO_AUTH_PROVIDERS = new Set(["sdwebui", "comfyui"]);

/**
 * Handle image generation request
 * @param {Request} request
 */
export async function handleImageGeneration(request) {
  let body;
  try {
    body = await request.json();
  } catch {
    return errorResponse(HTTP_STATUS.BAD_REQUEST, "Invalid JSON body");
  }

  const preferredConnectionId = request.headers.get("x-connection-id") || null;
  const wantsStream = (request.headers.get("accept") || "").includes("text/event-stream");
  const modelStr = body.model;

  const apiKey = extractApiKey(request);
  const settings = await getSettings();
  if (settings.requireApiKey) {
    if (!apiKey) return errorResponse(HTTP_STATUS.UNAUTHORIZED, "Missing API key");
    const valid = await isValidApiKey(apiKey);
    if (!valid) return errorResponse(HTTP_STATUS.UNAUTHORIZED, "Invalid API key");
  }

  if (!modelStr) return errorResponse(HTTP_STATUS.BAD_REQUEST, "Missing model");
  if (!body.prompt) return errorResponse(HTTP_STATUS.BAD_REQUEST, "Missing required field: prompt");

  const modelInfo = await getModelInfo(modelStr);
  if (!modelInfo.provider) return errorResponse(HTTP_STATUS.BAD_REQUEST, "Invalid model format");

  const { provider, model } = modelInfo;

  // noAuth providers — no credential needed
  if (NO_AUTH_PROVIDERS.has(provider)) {
    const result = await handleImageGenerationCore({
      body,
      modelInfo: { provider, model },
      credentials: null,
    });
    if (result.success) return result.response;
    return errorResponse(result.status || HTTP_STATUS.BAD_GATEWAY, result.error || "Image generation failed");
  }

  // Credentialed providers — fallback loop
  const excludeConnectionIds = new Set();
  let lastError = null;
  let lastStatus = null;

  while (true) {
    const credentials = await getProviderCredentials(provider, excludeConnectionIds, model, { preferredConnectionId });

    if (!credentials || credentials.allRateLimited) {
      if (credentials?.allRateLimited) {
        const errorMsg = lastError || credentials.lastError || "Unavailable";
        const status = lastStatus || Number(credentials.lastErrorCode) || HTTP_STATUS.SERVICE_UNAVAILABLE;
        return unavailableResponse(status, `[${provider}/${model}] ${errorMsg}`, credentials.retryAfter, credentials.retryAfterHuman);
      }
      if (excludeConnectionIds.size === 0) {
        return errorResponse(HTTP_STATUS.BAD_REQUEST, `No credentials for provider: ${provider}`);
      }
      return errorResponse(lastStatus || HTTP_STATUS.SERVICE_UNAVAILABLE, lastError || "All accounts unavailable");
    }

    const refreshedCredentials = await checkAndRefreshToken(provider, credentials);

    const result = await handleImageGenerationCore({
      body,
      modelInfo: { provider, model },
      credentials: refreshedCredentials,
      streamToClient: wantsStream,
      onCredentialsRefreshed: async (newCreds) => {
        await updateProviderCredentials(credentials.connectionId, {
          accessToken: newCreds.accessToken,
          refreshToken: newCreds.refreshToken,
          providerSpecificData: newCreds.providerSpecificData,
          testStatus: "active"
        });
      },
      onRequestSuccess: async () => {
        await clearAccountError(credentials.connectionId, credentials, model);
      }
    });

    if (result.success) return result.response;

    const { shouldFallback } = await markAccountUnavailable(credentials.connectionId, result.status, result.error, provider, model);

    if (shouldFallback) {
      excludeConnectionIds.add(credentials.connectionId);
      lastError = result.error;
      lastStatus = result.status;
      continue;
    }

    return result.response;
  }
}