// src/components/KnowledgePanel.tsx
import { useState, useEffect } from 'react';
import apiClient from '../services/api';
import TileCard from './TileCard'; // Assuming TileCard is in the same directory

// Define the TypeScript interfaces matching the backend schema
interface VerificationMark {
    verification_type: string;
    is_expert_verified: boolean;
    expert_orcid_id?: string;
    expert_name?: string;
    verification_date?: string;
    verification_count: number;
}

interface KnowledgeTile {
    tile_id: string;
    domain_id: string;
    topic: string;
    content_preview: string;
    created_at: string;
    updated_at: string;
    verification_mark: VerificationMark;
    contributor_id?: string;
    confidence_score: number;
    tags: string[];
}

interface DomainConfig { // Also defined in DBManager, but local here for clarity
  domain_id: string;
  name: string;
}

const KnowledgePanel = () => {
  const [tiles, setTiles] = useState<KnowledgeTile[]>([]);
  const [isLoading, setIsLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const [page, setPage] = useState(1);
  const [hasMore, setHasMore] = useState(false);

  // Filter states
  const [searchTerm, setSearchTerm] = useState('');
  const [filterDomain, setFilterDomain] = useState('');
  const [availableDomains, setAvailableDomains] = useState<DomainConfig[]>([]);
  const [isExporting, setIsExporting] = useState(false);

  useEffect(() => {
    const fetchDomains = async () => {
      try {
        const response = await apiClient.get('/config/domains');
        setAvailableDomains(response.data);
      } catch (err) {
        console.error("Failed to fetch domains:", err);
        setError("Failed to load domain filters.");
      }
    };
    fetchDomains();
  }, []);

  useEffect(() => {
    const fetchTiles = async () => {
      setIsLoading(true);
      setError(null);
      try {
        const response = await apiClient.get('/knowledge/', {
          params: {
            page: page,
            page_size: 20,
            domain_id: filterDomain || undefined, // Only send if not empty
            search: searchTerm || undefined,      // Only send if not empty
          },
        });
        setTiles(response.data.tiles);
        setHasMore(response.data.has_more);
      } catch (err) {
        setError('Failed to fetch knowledge tiles.');
        console.error(err);
      } finally {
        setIsLoading(false);
      }
    };

    fetchTiles();
  }, [page, filterDomain, searchTerm]); // Re-fetch tiles when page, filterDomain, or searchTerm changes

  const handleExportIath = async () => {
    setIsExporting(true);
    try {
      const response = await apiClient.get('/knowledge/export/iath', {
        params: {
          domain_id: filterDomain || undefined,
          precision: 'standard' // List View uses standard precision
        },
        responseType: 'blob' // Important for binary data
      });

      // Create download link
      const url = window.URL.createObjectURL(new Blob([response.data]));
      const link = document.createElement('a');
      link.href = url;

      // Extract filename from Content-Disposition header or use default
      const contentDisposition = response.headers['content-disposition'];
      let filename = 'knowledge_base.iath';
      if (contentDisposition) {
        const filenameMatch = contentDisposition.match(/filename="?(.+)"?/);
        if (filenameMatch) {
          filename = filenameMatch[1];
        }
      }

      link.setAttribute('download', filename);
      document.body.appendChild(link);
      link.click();
      link.remove();
      window.URL.revokeObjectURL(url);
    } catch (err) {
      console.error('Export failed:', err);
      setError('Failed to export .iath file.');
    } finally {
      setIsExporting(false);
    }
  };

  const handleDomainUpdate = async (tileId: string, newDomainId: string) => {
    try {
      await apiClient.patch(`/knowledge/${tileId}/domain`, null, {
        params: { domain_id: newDomainId }
      });

      // Update the tile in the local state
      setTiles(prev => prev.map(tile =>
        tile.tile_id === tileId ? { ...tile, domain_id: newDomainId } : tile
      ));
    } catch (err) {
      console.error('Failed to update domain:', err);
      setError('Failed to update domain.');
    }
  };

  return (
    <div>
      <div className="panel-section">
        <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', marginBottom: '1rem' }}>
          <h3 style={{ margin: 0 }}>Knowledge Browser</h3>
          <button
            onClick={handleExportIath}
            disabled={isExporting}
            style={{
              padding: '8px 16px',
              fontSize: '14px',
              backgroundColor: isExporting ? '#555' : '#007acc',
              cursor: isExporting ? 'not-allowed' : 'pointer'
            }}
          >
            {isExporting ? 'Exporting...' : '📦 Export .iath'}
          </button>
        </div>
        <div className="flex flex-col gap-2 mb-4">
          <input
            type="text"
            placeholder="Search tiles by topic or content..."
            value={searchTerm}
            onChange={(e) => {
              setSearchTerm(e.target.value);
              setPage(1); // Reset to first page on search
            }}
          />
          <select
            value={filterDomain}
            onChange={(e) => {
              setFilterDomain(e.target.value);
              setPage(1); // Reset to first page on filter change
            }}
          >
            <option value="">All Domains</option>
            {availableDomains.map(domain => (
              <option key={domain.domain_id} value={domain.domain_id}>
                {domain.name}
              </option>
            ))}
          </select>
        </div>
      </div>

      {isLoading && <p>Loading knowledge base... <span className="loading-dots"><span>.</span><span>.</span><span>.</span></span></p>}
      {error && <p style={{ color: 'red', marginBottom: '1rem', padding: '0.5rem', backgroundColor: 'rgba(255,0,0,0.1)', borderRadius: '5px' }}>{error}</p>}
      
      {!isLoading && !error && (
        <>
          <div className="space-y-4">
            {tiles.map(tile => (
              <TileCard
                key={tile.tile_id}
                tile={tile}
                availableDomains={availableDomains}
                onDomainChange={handleDomainUpdate}
              />
            ))}
          </div>
          
          <div className="flex justify-between mt-4">
            <button onClick={() => setPage(p => Math.max(1, p - 1))} disabled={page === 1}>
              Previous
            </button>
            <span>Page {page}</span>
            <button onClick={() => setPage(p => p + 1)} disabled={!hasMore}>
              Next
            </button>
          </div>
        </>
      )}
    </div>
  );
};

export default KnowledgePanel;