import { useState, useCallback, useRef, useEffect } from 'react';
import { UseFormReturn } from 'react-hook-form';
import { toast } from 'sonner';
import { focusGroupsApi } from '@/lib/api';
import { useCancellableGeneration } from '@/hooks/useCancellableGeneration';
import { waitForTaskResult } from '@/lib/taskPolling';
import { getSocket } from '@/services/websocketServiceNew';

interface DiscussionGuideGenerationOptions {
  form: UseFormReturn<any>;
}

interface DiscussionGuideGenerationReturn {
  discussionGuide: any | null;
  setDiscussionGuide: (guide: any | null) => void;
  discussionGuideRef: React.MutableRefObject<any | null>;
  isEditingGuide: boolean;
  setIsEditingGuide: (editing: boolean) => void;
  guideGenerationState: {
    isGenerating: boolean;
    isComplete: boolean;
    hasError: boolean;
    isCancelling: boolean;
    taskId: string | null;
  };
  guideGenerationControls: {
    startGeneration: () => void;
    setTaskId: (id: string) => void;
    completeGeneration: () => void;
    failGeneration: (error: string) => void;
    cancelGeneration: () => void;
    resetGeneration: () => void;
  };
  isGuideProgressModalOpen: boolean;
  setIsGuideProgressModalOpen: (open: boolean) => void;
  isDownloadingGuide: boolean;
  generateDiscussionGuide: (values: any, focusGroupId?: string) => Promise<string>;
  handleSaveDiscussionGuide: (updatedGuide: any) => void;
  handleDownloadDiscussionGuide: () => Promise<void>;
  handleEditingStateChange: (editing: boolean) => void;
  handleGuideProgressComplete: () => void;
  isJsonFormat: (guide: any) => boolean;
}

export function useDiscussionGuideGeneration({
  form,
}: DiscussionGuideGenerationOptions): DiscussionGuideGenerationReturn {
  const socket = getSocket();
  const [guideGenerationState, guideGenerationControls] = useCancellableGeneration('discussion guide generation', socket);
  const [isGuideProgressModalOpen, setIsGuideProgressModalOpen] = useState(false);

  const [discussionGuide, setDiscussionGuide] = useState<any | null>(null);
  const [isEditingGuide, setIsEditingGuide] = useState(false);
  const [isDownloadingGuide, setIsDownloadingGuide] = useState(false);

  // Ref to access current discussionGuide in callbacks without adding it as dependency
  const discussionGuideRef = useRef(discussionGuide);
  discussionGuideRef.current = discussionGuide;

  // Helper function to determine if discussion guide is JSON format
  const isJsonFormat = useCallback((guide: any): boolean => {
    return guide && typeof guide === 'object' && guide.title && guide.sections;
  }, []);

  // Function to generate a discussion guide via the API
  const generateDiscussionGuide = useCallback(async (values: any, focusGroupId?: string): Promise<string> => {
    guideGenerationControls.startGeneration();
    setIsGuideProgressModalOpen(true);

    try {
      const requestData = {
        name: values.focusGroupName,
        description: values.researchBrief,
        objective: values.researchBrief,
        topic: values.discussionTopics,
        duration: parseInt(values.duration),
        llm_model: values.llm_model,
        reasoning_effort: values.reasoning_effort,
        verbosity: values.verbosity
      };

      const response = focusGroupId
        ? await focusGroupsApi.generateDiscussionGuideForGroup(focusGroupId, requestData)
        : await focusGroupsApi.generateDiscussionGuide(requestData);

      const taskId = response.data?.task_id;
      if (taskId) {
        guideGenerationControls.setTaskId(taskId);
      }

      // Backend returns 202 immediately — wait for result via HTTP polling
      if (response.status === 202 && taskId) {
        const taskResult = await waitForTaskResult(taskId);
        if (taskResult.status === 'completed') {
          const guide = taskResult.result?.discussionGuide;
          if (guide) {
            guideGenerationControls.completeGeneration();
            return guide;
          } else {
            guideGenerationControls.failGeneration('No guide returned');
            throw new Error('No discussion guide returned');
          }
        } else if (taskResult.status === 'failed') {
          guideGenerationControls.failGeneration(taskResult.error || 'Generation failed');
          throw new Error(taskResult.error || 'Generation failed');
        } else {
          // cancelled
          return '';
        }
      }

      // Fallback: synchronous response with guide in body
      if (response.data?.discussionGuide) {
        guideGenerationControls.completeGeneration();
        return response.data.discussionGuide;
      }

      throw new Error("Failed to generate discussion guide");
    } catch (error: any) {
      if (error.response?.status === 499) {
        return '';
      }

      console.error("Error generating discussion guide:", error);
      guideGenerationControls.failGeneration(error.message || 'Failed to generate discussion guide');

      let errorMessage = 'Unknown error occurred';
      if (error?.response?.data?.error) {
        errorMessage = error.response.data.error;
      } else if (error?.message) {
        errorMessage = error.message;
      }

      toast.error("Failed to generate discussion guide", {
        description: errorMessage,
        action: {
          label: "Retry",
          onClick: () => generateDiscussionGuide(values, focusGroupId)
        }
      });

      throw error;
    }
  }, [guideGenerationControls]);

  const handleGuideProgressComplete = useCallback(() => {
    setIsGuideProgressModalOpen(false);
    guideGenerationControls.resetGeneration();
  }, [guideGenerationControls]);

  // Stable callback for saving discussion guide changes
  const handleSaveDiscussionGuide = useCallback((updatedGuide: any) => {
    if (!isEditingGuide) {
      setDiscussionGuide(updatedGuide);
      toast.success('Discussion guide updated', {
        description: 'Your changes have been saved.'
      });
    } else {
      discussionGuideRef.current = updatedGuide;
    }
  }, [isEditingGuide]);

  // Handle editing state changes from DiscussionGuideViewer
  const handleEditingStateChange = useCallback((editing: boolean) => {
    setIsEditingGuide(editing);

    if (!editing && discussionGuideRef.current) {
      setDiscussionGuide(discussionGuideRef.current);
    }
  }, []);

  // Function to download discussion guide as markdown
  const handleDownloadDiscussionGuide = useCallback(async () => {
    if (!discussionGuideRef.current) {
      toast.error("No discussion guide available", {
        description: "Please generate a discussion guide first"
      });
      return;
    }

    setIsDownloadingGuide(true);

    try {
      const { downloadDiscussionGuideAsMarkdown } = await import('@/utils/discussionGuideMarkdown');
      const formValues = form.getValues();

      downloadDiscussionGuideAsMarkdown(discussionGuideRef.current, formValues.focusGroupName);

      toast.success("Discussion guide downloaded", {
        description: "The guide has been saved to your downloads folder"
      });
    } catch (error) {
      console.error('Error downloading discussion guide:', error);
      toast.error("Download failed", {
        description: "Unable to download the discussion guide. Please try again."
      });
    } finally {
      setIsDownloadingGuide(false);
    }
  }, [form]);

  return {
    discussionGuide,
    setDiscussionGuide,
    discussionGuideRef,
    isEditingGuide,
    setIsEditingGuide,
    guideGenerationState,
    guideGenerationControls,
    isGuideProgressModalOpen,
    setIsGuideProgressModalOpen,
    isDownloadingGuide,
    generateDiscussionGuide,
    handleSaveDiscussionGuide,
    handleDownloadDiscussionGuide,
    handleEditingStateChange,
    handleGuideProgressComplete,
    isJsonFormat,
  };
}