/**
 * Generate API Route
 * 
 * TIMEOUT CONFIGURATION:
 * - maxDuration: Only applies on Vercel, not locally
 * - AbortSignal.timeout: Controls outgoing fetch to providers
 * - For local development, server.requestTimeout must be set in server.js (Node.js default is 5 minutes)
 * 
 * FAL.AI QUEUE API NOTE:
 * Uses generateWithFalQueue with async queue submission + polling.
 * Images are uploaded to fal CDN before submission to avoid payload size issues.
 */
import { NextRequest, NextResponse } from "next/server";
import { GenerateRequest, GenerateResponse, ModelType, SelectedModel, ProviderType } from "@/types";
import { GenerationInput, ModelCapability } from "@/lib/providers/types";
import { generateWithGemini, generateWithGeminiVideo } from "./providers/gemini";
import { generateWithReplicate } from "./providers/replicate";
import { clearFalInputMappingCache as _clearFalInputMappingCache, generateWithFalQueue } from "./providers/fal";
import { submitKieTask } from "./providers/kie";
import { generateWithWaveSpeed } from "./providers/wavespeed";
import { generateWithNewApiWG } from "./providers/newapiwg";
import { submitPopiTask } from "./providers/popiserver";
import { getRequestToken, requireConfiguredValue, requireLogin } from "../_auth";
import { ApiError, apiErrorResponse } from "../_errors";
import { resolveUserGatewayApiKey } from "../_gatewayApiKey";
import { resolveTemporaryImageUrlsInArray } from "@/lib/images/temporaryUrls";

// Re-export for backward compatibility (test file imports from route)
export const clearFalInputMappingCache = _clearFalInputMappingCache;

export const maxDuration = 600; // 10 minute timeout for video generation polling
export const dynamic = 'force-dynamic'; // Ensure this route is always dynamic


/**
 * Extended request format that supports both legacy and multi-provider requests
 */
interface MultiProviderGenerateRequest extends GenerateRequest {
  selectedModel?: SelectedModel;
  parameters?: Record<string, unknown>;
  /** Dynamic inputs from schema-based connections (e.g., image_url, tail_image_url, prompt) */
  dynamicInputs?: Record<string, string | string[]>;
}

interface ProviderConnectionParams {
  apiKey?: string;
  baseUrl?: string | null;
}

type RequiredSelectedModel = SelectedModel & {
  modelId: string;
  displayName: string;
};

const providerConnectionConfig: Partial<Record<ProviderType, {
  apiKeyHeader?: string;
  apiKeyEnv?: string;
  baseUrlHeader?: string;
  baseUrlEnv?: string;
}>> = {
  newapiwg: {
    baseUrlHeader: "X-NewApiWG-Base-URL",
    baseUrlEnv: "NEWAPIWG_BASE_URL",
  },
  gemini: {
    apiKeyHeader: "X-Gemini-API-Key",
    apiKeyEnv: "GEMINI_API_KEY",
  },
  replicate: {
    apiKeyHeader: "X-Replicate-API-Key",
    apiKeyEnv: "REPLICATE_API_KEY",
  },
  fal: {
    apiKeyHeader: "X-Fal-API-Key",
    apiKeyEnv: "FAL_API_KEY",
  },
  kie: {
    apiKeyHeader: "X-Kie-Key",
    apiKeyEnv: "KIE_API_KEY",
  },
  wavespeed: {
    apiKeyHeader: "X-WaveSpeed-Key",
    apiKeyEnv: "WAVESPEED_API_KEY",
  },
};

export function getConnectionParams(request: NextRequest, provider: ProviderType): ProviderConnectionParams {
  const config = providerConnectionConfig[provider];
  if (!config) return {};

  const apiKey = config.apiKeyHeader && config.apiKeyEnv
    ? request.headers.get(config.apiKeyHeader) || process.env[config.apiKeyEnv] || undefined
    : undefined;
  const baseUrl = config.baseUrlHeader && config.baseUrlEnv
    ? request.headers.get(config.baseUrlHeader) || process.env[config.baseUrlEnv] || null
    : undefined;

  return { apiKey, baseUrl };
}

function requireSelectedModel(
  selectedModel: SelectedModel | undefined,
  providerName: string
): RequiredSelectedModel {
  if (!selectedModel?.modelId || !selectedModel?.displayName) {
    throw ApiError.badRequest(
      `selectedModel with modelId and displayName is required for ${providerName}`
    );
  }
  return selectedModel as RequiredSelectedModel;
}

export function buildMediaResponse(
  output: { type: string; data: string; url?: string },
  outputs?: Array<{ type: string; data: string; url?: string }>
): NextResponse {
  if (output.type === "3d") {
    return NextResponse.json<GenerateResponse>({
      success: true,
      model3dUrl: output.url,
      contentType: "3d",
    });
  }

  if (output.type === "video") {
    const isLarge = !output.data && output.url;
    return NextResponse.json<GenerateResponse>({
      success: true,
      video: isLarge ? undefined : output.data,
      videoUrl: isLarge ? output.url : undefined,
      contentType: "video",
    });
  }

  if (output.type === "audio") {
    const isLarge = !output.data && output.url;
    return NextResponse.json<GenerateResponse>({
      success: true,
      audio: isLarge ? undefined : output.data,
      audioUrl: isLarge ? output.url : undefined,
      contentType: "audio",
    });
  }

  const image = output.data || output.url;
  const images = outputs
    ?.filter((item) => item.type === "image")
    .map((item) => item.data || item.url)
    .filter((item): item is string => typeof item === "string" && item.length > 0);

  return NextResponse.json<GenerateResponse>({
    success: true,
    image,
    ...(images && images.length > 1 ? { images } : {}),
    contentType: "image",
  });
}

function capabilitiesForMediaType(mediaType?: string): ModelCapability[] {
  const map: Record<string, ModelCapability[]> = {
    audio: ["text-to-audio"],
    video: ["text-to-video"],
    "3d": ["text-to-3d"],
  };
  return map[mediaType ?? ""] ?? ["text-to-image"];
}

function mediaTypeForCapabilities(capabilities: string[] | undefined, fallback?: string): string {
  if (fallback) return fallback;
  if (capabilities?.some((capability) => capability.includes("audio"))) return "audio";
  if (capabilities?.some((capability) => capability.includes("video"))) return "video";
  if (capabilities?.some((capability) => capability.includes("3d"))) return "3d";
  return "image";
}

function mergeImageGenerationParameters(
  parameters: Record<string, unknown> | undefined,
  aspectRatio: string | undefined,
  resolution: string | undefined
): Record<string, unknown> | undefined {
  const merged = { ...(parameters || {}) };
  if (aspectRatio) {
    merged.aspectRatio = aspectRatio;
    merged.aspect_ratio = aspectRatio;
  }
  if (resolution) {
    merged.resolution = resolution;
    merged.imageSize = resolution;
  }
  return Object.keys(merged).length > 0 ? merged : undefined;
}

async function readGenerateRequest(request: NextRequest): Promise<MultiProviderGenerateRequest> {
  try {
    return await request.json();
  } catch (error) {
    const message = error instanceof Error ? error.message : "";
    if (
      error instanceof SyntaxError ||
      /json|unterminated string|unexpected end/i.test(message)
    ) {
      throw ApiError.badRequest(
        "生成请求过大或不完整：参考图数据可能在发送时被截断。请重试，或压缩参考图后再生成。"
      );
    }
    throw error;
  }
}

export async function POST(request: NextRequest) {
  const requestId = Math.random().toString(36).substring(7);
  console.log(`\n[API:${requestId}] ========== NEW GENERATE REQUEST ==========`);

  try {
    const body = await readGenerateRequest(request);
    const {
      images,
      prompt,
      model = "nano-banana-pro",
      aspectRatio,
      resolution,
      useGoogleSearch,
      useImageSearch,
      selectedModel,
      parameters,
      dynamicInputs,
      mediaType,
    } = body;
    const provider: ProviderType = selectedModel?.provider || "gemini";
    const requestImages = provider === "newapiwg"
      ? images || []
      : resolveTemporaryImageUrlsInArray(images);

    // Prompt is required unless:
    // - Provided via dynamicInputs
    // - Images are provided (image-to-video/image-to-image models)
    // - Dynamic inputs contain image frames (first_frame, last_frame, etc.)
    const hasPrompt = prompt || (dynamicInputs && (
      typeof dynamicInputs.prompt === 'string'
        ? dynamicInputs.prompt
        : Array.isArray(dynamicInputs.prompt) && dynamicInputs.prompt.length > 0
    ));
    const hasImages = requestImages.length > 0;
    const hasMediaInputs = dynamicInputs && Object.keys(dynamicInputs).some(key =>
      key.includes('frame') || key.includes('image') || key.includes('video') || key.includes('audio')
    );

    if (!hasPrompt && !hasImages && !hasMediaInputs) {
      throw ApiError.badRequest("Prompt or image input is required");
    }

    // Determine which provider to use
    const login = provider !== "newapiwg" ? requireLogin(request) : null;
    const loginToken = login?.token ?? getRequestToken(request);
    console.log(`[API:${requestId}] Provider: ${provider}, Model: ${selectedModel?.modelId || model}`);

    // Route to appropriate provider
    if (provider === "popiserver") {
      const selected = requireSelectedModel(selectedModel, "Popi Models");
      const selectedCapabilities = selected.capabilities as ModelCapability[] | undefined;
      const genInput: GenerationInput = {
        model: {
          id: selected.modelId,
          name: selected.displayName,
          provider: "popiserver",
          capabilities: selectedCapabilities || capabilitiesForMediaType(mediaType),
          description: null,
          metadata: selected.metadata,
        },
        prompt: prompt || "",
        images: images ? [...images] : [],
        parameters: mergeImageGenerationParameters(parameters, aspectRatio, resolution),
        dynamicInputs,
      };

      const { taskId } = await submitPopiTask(request, login!.token, genInput);
      return NextResponse.json<GenerateResponse>({
        success: true,
        polling: true,
        taskId,
        pollProvider: "popiserver",
        pollModelId: selected.modelId,
        pollModelName: selected.displayName,
        pollMediaType: mediaTypeForCapabilities(selected.capabilities, mediaType),
      });
    }

    if (provider === "newapiwg") {
      const selected = requireSelectedModel(selectedModel, "NewApiWG");

      const { baseUrl: newApiWGBaseUrl } = getConnectionParams(request, "newapiwg");
      const apiKey = await resolveUserGatewayApiKey(request);

      const genInput: GenerationInput = {
        model: {
          id: selected.modelId,
          name: selected.displayName,
          provider: "newapiwg",
          capabilities: (selected.capabilities as ModelCapability[] | undefined) || capabilitiesForMediaType(mediaType),
          description: null,
        },
        prompt: prompt || "",
        images: requestImages,
        parameters: mergeImageGenerationParameters(parameters, aspectRatio, resolution),
        dynamicInputs,
      };

      const result = await generateWithNewApiWG(apiKey, newApiWGBaseUrl ?? null, genInput, loginToken);
      if (!result.success) {
        return NextResponse.json<GenerateResponse>(
          { success: false, requestId, error: result.error || "Generation failed" },
          { status: 500 }
        );
      }

      const output = result.outputs?.[0];
      if (!output?.data && !output?.url) {
        return NextResponse.json<GenerateResponse>(
          { success: false, requestId, error: "No output in generation result" },
          { status: 500 }
        );
      }

      return buildMediaResponse(output);
    }

    if (provider === "replicate") {
      const selected = requireSelectedModel(selectedModel, "Replicate");

      // User-provided key takes precedence over env variable
      const { apiKey: replicateApiKey } = getConnectionParams(request, "replicate");
      const apiKey = requireConfiguredValue(
        replicateApiKey,
        "Replicate API key not configured. Add REPLICATE_API_KEY to .env.local or configure in Settings."
      );

      // Keep Data URIs as-is since localhost URLs won't work (provider can't reach them)
      const processedImages = requestImages;

      // Process dynamicInputs: filter empty values, keep Data URIs
      let processedDynamicInputs: Record<string, string | string[]> | undefined = undefined;

      if (dynamicInputs) {
        processedDynamicInputs = {};
        for (const key of Object.keys(dynamicInputs)) {
          const value = dynamicInputs[key];

          // Skip empty/null/undefined values (arrays pass through)
          if (value === null || value === undefined || value === '') {
            continue;
          }

          // Keep the value as-is (Data URIs work with Replicate)
          processedDynamicInputs[key] = value;
        }
      }

      // Build generation input
      const genInput: GenerationInput = {
        model: {
          id: selected.modelId,
          name: selected.displayName,
          provider: "replicate",
          capabilities: capabilitiesForMediaType(mediaType),
          description: null,
        },
        prompt: prompt || "",
        images: processedImages,
        parameters,
        dynamicInputs: processedDynamicInputs,
      };

      const result = await generateWithReplicate(requestId, apiKey, genInput);

      if (!result.success) {
        return NextResponse.json<GenerateResponse>(
          {
            success: false,
            error: result.error || "Generation failed",
          },
          { status: 500 }
        );
      }

      // Return first output
      const output = result.outputs?.[0];
      if (!output?.data && !output?.url) {
        return NextResponse.json<GenerateResponse>(
          { success: false, error: "No output in generation result" },
          { status: 500 }
        );
      }

      return buildMediaResponse(output);
    }

    if (provider === "fal") {
      const selected = requireSelectedModel(selectedModel, "fal.ai");

      // User-provided key takes precedence over env variable
      const { apiKey: falApiKey } = getConnectionParams(request, "fal");

      if (!falApiKey) {
        console.warn(`[API:${requestId}] No FAL API key configured. Proceeding without auth (rate-limited).`);
      }

      // Pass images as-is; generateWithFalQueue uploads base64 to CDN internally
      const processedImages = requestImages;

      // Process dynamicInputs: filter empty values
      let processedDynamicInputs: Record<string, string | string[]> | undefined = undefined;

      if (dynamicInputs) {
        processedDynamicInputs = {};
        for (const key of Object.keys(dynamicInputs)) {
          const value = dynamicInputs[key];

          // Skip empty/null/undefined values (arrays pass through)
          if (value === null || value === undefined || value === '') {
            continue;
          }

          // Keep the value as-is; CDN upload happens in generateWithFalQueue
          processedDynamicInputs[key] = value;
        }
      }

      // Build generation input
      const genInput: GenerationInput = {
        model: {
          id: selected.modelId,
          name: selected.displayName,
          provider: "fal",
          capabilities: capabilitiesForMediaType(mediaType),
          description: null,
        },
        prompt: prompt || "",
        images: processedImages,
        parameters,
        dynamicInputs: processedDynamicInputs,
      };

      const result = await generateWithFalQueue(requestId, falApiKey || null, genInput);

      if (!result.success) {
        return NextResponse.json<GenerateResponse>(
          {
            success: false,
            error: result.error || "Generation failed",
          },
          { status: 500 }
        );
      }

      // Return first output
      const output = result.outputs?.[0];
      if (!output?.data && !output?.url) {
        return NextResponse.json<GenerateResponse>(
          { success: false, error: "No output in generation result" },
          { status: 500 }
        );
      }

      return buildMediaResponse(output);
    }

    if (provider === "kie") {
      const selected = requireSelectedModel(selectedModel, "Kie.ai");

      // User-provided key takes precedence over env variable
      const { apiKey: kieApiKey } = getConnectionParams(request, "kie");
      const apiKey = requireConfiguredValue(
        kieApiKey,
        "Kie.ai API key not configured. Add KIE_API_KEY to .env.local or configure in Settings."
      );

      // Process images - Kie requires URLs, we'll upload base64 images in generateWithKie
      const processedImages = requestImages;

      // Process dynamicInputs: filter empty values
      let processedDynamicInputs: Record<string, string | string[]> | undefined = undefined;

      if (dynamicInputs) {
        processedDynamicInputs = {};
        for (const key of Object.keys(dynamicInputs)) {
          const value = dynamicInputs[key];

          // Skip empty/null/undefined values
          if (value === null || value === undefined || value === '') {
            continue;
          }

          processedDynamicInputs[key] = value;
        }
      }

      // Build generation input
      const genInput: GenerationInput = {
        model: {
          id: selected.modelId,
          name: selected.displayName,
          provider: "kie",
          capabilities: capabilitiesForMediaType(mediaType),
          description: null,
        },
        prompt: prompt || "",
        images: processedImages,
        parameters,
        dynamicInputs: processedDynamicInputs,
      };

      // Submit task and return immediately — client polls for completion
      try {
        const { taskId, isVeo } = await submitKieTask(requestId, apiKey, genInput);
        return NextResponse.json<GenerateResponse>({
          success: true,
          polling: true,
          taskId,
          pollProvider: 'kie',
          pollModelId: selected.modelId,
          pollModelName: selected.displayName,
          pollMediaType: mediaType || 'image',
        });
      } catch (error) {
        return NextResponse.json<GenerateResponse>(
          {
            success: false,
            error: error instanceof Error ? error.message : "Task submission failed",
          },
          { status: 500 }
        );
      }
    }

    if (provider === "wavespeed") {
      const selected = requireSelectedModel(selectedModel, "WaveSpeed");

      // User-provided key takes precedence over env variable
      const { apiKey: wavespeedApiKey } = getConnectionParams(request, "wavespeed");
      const apiKey = requireConfiguredValue(
        wavespeedApiKey,
        "WaveSpeed API key not configured. Add WAVESPEED_API_KEY to .env.local or configure in Settings."
      );

      // Keep Data URIs as-is since localhost URLs won't work
      const processedImages = requestImages;

      // Process dynamicInputs: filter empty values
      let processedDynamicInputs: Record<string, string | string[]> | undefined = undefined;

      if (dynamicInputs) {
        processedDynamicInputs = {};
        for (const key of Object.keys(dynamicInputs)) {
          const value = dynamicInputs[key];

          // Skip empty/null/undefined values
          if (value === null || value === undefined || value === '') {
            continue;
          }

          processedDynamicInputs[key] = value;
        }
      }

      // Build generation input
      const genInput: GenerationInput = {
        model: {
          id: selected.modelId,
          name: selected.displayName,
          provider: "wavespeed",
          capabilities: capabilitiesForMediaType(mediaType),
          description: null,
        },
        prompt: prompt || "",
        images: processedImages,
        parameters,
        dynamicInputs: processedDynamicInputs,
      };

      const result = await generateWithWaveSpeed(requestId, apiKey, genInput);

      if (!result.success) {
        return NextResponse.json<GenerateResponse>(
          {
            success: false,
            error: result.error || "Generation failed",
          },
          { status: 500 }
        );
      }

      // Return first output
      const output = result.outputs?.[0];
      if (!output?.data && !output?.url) {
        return NextResponse.json<GenerateResponse>(
          { success: false, error: "No output in generation result" },
          { status: 500 }
        );
      }

      return buildMediaResponse(output);
    }

    // Default: Use Gemini
    // User-provided key (from settings) takes precedence over env variable
    const { apiKey: geminiApiKey } = getConnectionParams(request, "gemini");

    if (!geminiApiKey) {
      throw ApiError.config("API key not configured. Add GEMINI_API_KEY to .env.local or configure in Settings.", 500);
    }

    // Use selectedModel.modelId if available (new format), fallback to legacy model field
    const geminiModel = (selectedModel?.modelId as ModelType) || model;

    // Resolve prompt: use top-level prompt, fall back to dynamicInputs.prompt
    // This handles cases where the prompt arrives via dynamicInputs instead of top-level
    let resolvedPrompt = prompt;
    if (!resolvedPrompt && dynamicInputs?.prompt) {
      resolvedPrompt = Array.isArray(dynamicInputs.prompt)
        ? dynamicInputs.prompt[0]
        : dynamicInputs.prompt;
    }
    // Validate: if a prompt was provided but isn't a string (corrupted data), return clear error
    // If no prompt provided but images exist, that's valid (image-to-image)
    if (resolvedPrompt !== undefined && resolvedPrompt !== null && typeof resolvedPrompt !== 'string') {
      return NextResponse.json<GenerateResponse>(
        { success: false, error: "prompt must be a string" },
        { status: 400 }
      );
    }

    // Check if this is a Veo video model request
    if (selectedModel?.modelId?.startsWith("veo-")) {
      // Merge negative prompt from dynamic inputs (connected handle) into parameters
      const veoParams = { ...(parameters || {}) };
      if (dynamicInputs?.negative_prompt) {
        const neg = Array.isArray(dynamicInputs.negative_prompt)
          ? dynamicInputs.negative_prompt[0]
          : dynamicInputs.negative_prompt;
        if (neg) veoParams.negativePrompt = neg;
      }
      const result = await generateWithGeminiVideo(
        requestId,
        geminiApiKey,
        selectedModel.modelId,
        resolvedPrompt || "",
        requestImages,
        veoParams,
      );

      if (!result.success) {
        return NextResponse.json<GenerateResponse>(
          { success: false, error: result.error || "Video generation failed" },
          { status: 500 }
        );
      }

      const output = result.outputs?.[0];
      if (!output?.data && !output?.url) {
        return NextResponse.json<GenerateResponse>(
          { success: false, error: "No output in video generation result" },
          { status: 500 }
        );
      }

      return buildMediaResponse(output);
    }

    return await generateWithGemini(
      requestId,
      geminiApiKey,
      resolvedPrompt,
      requestImages,
      geminiModel,
      aspectRatio,
      resolution,
      useGoogleSearch,
      useImageSearch
    );
  } catch (error) {
    if (error instanceof ApiError) {
      return apiErrorResponse(error, requestId);
    }

    // Extract error information
    let errorMessage = "Generation failed";
    let errorDetails = "";

    if (error instanceof Error) {
      errorMessage = error.message;
      if ("cause" in error && error.cause) {
        errorDetails = JSON.stringify(error.cause);
      }
    }

    // Try to extract more details from API errors
    if (error && typeof error === "object") {
      const apiError = error as Record<string, unknown>;
      if (apiError.status) {
        errorDetails += ` Status: ${apiError.status}`;
      }
      if (apiError.statusText) {
        errorDetails += ` ${apiError.statusText}`;
      }
    }

    // Handle rate limiting
    if (errorMessage.includes("429")) {
      return NextResponse.json<GenerateResponse>(
        {
          success: false,
          error: "Rate limit reached. Please wait and try again.",
        },
        { status: 429 }
      );
    }

    console.error(`[API:${requestId}] Generation error: ${errorMessage}${errorDetails ? ` (${errorDetails.substring(0, 200)})` : ""}`);
    return NextResponse.json<GenerateResponse>(
        {
          success: false,
          requestId,
          error: errorMessage,
        },
      { status: 500 }
    );
  }
}