"use client";

import { useEffect, useState } from "react";
import { useParams, useNavigate } from "react-router-dom";
import apiService from "../services/apiService";
import type { MigrantProfile } from "../types/migrant";
import MigrantProfileComponent from "../components/MigrantProfileComponent";
import { Alert, AlertTitle, AlertDescription } from "@/components/ui/alert";
import { AlertCircle, Loader2 } from "lucide-react";
import { Button } from "@/components/ui/button";

// Helper function to calculate age at migration
const calculateAgeAtMigration = (birthDate: string | null | undefined, migrationDate: string | null | undefined): number => {
  if (!birthDate || !migrationDate) return 0;
  
  try {
    const normalizedBirthDate = birthDate.includes('.') ? birthDate.split('.')[0] + 'Z' : birthDate;
    const normalizedMigrationDate = migrationDate.includes('.') ? migrationDate.split('.')[0] + 'Z' : migrationDate;
    
    const birthYear = new Date(normalizedBirthDate).getFullYear();
    const migrationYear = new Date(normalizedMigrationDate).getFullYear();
    
    // Simple year difference calculation
    const age = migrationYear - birthYear;
    
    return age >= 0 ? age : 0;
  } catch (error) {
    console.error(`Error calculating age: birth=${birthDate}, migration=${migrationDate}`, error);
    return 0;
  }
};

const MigrantProfilePage = () => {
  const { id } = useParams<{ id: string }>();
  const navigate = useNavigate();
  const [migrant, setMigrant] = useState<MigrantProfile | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const [retryCount, setRetryCount] = useState(0);

  // Fetch migrant data when component mounts or ID changes
  useEffect(() => {
    const fetchMigrantData = async () => {
      // Reset state when ID changes
      setLoading(true);
      setMigrant(null);
      setError(null);
      
      if (!id) {
        setError('Missing migrant ID');
        setLoading(false);
        return;
      }
      
      try {
        // Fetch migrant data from the backend using apiService
        const data = await apiService.getRecordById(id);
        
        if (data) {
          // Data successfully retrieved - convert API data to MigrantProfile
          const migrantProfile: MigrantProfile = {
            id: data.person_id || id,
            firstName: data.christian_name || '',
            lastName: data.surname || '',
            middleName: '',
            birthDate: data.date_of_birth || '',
            birthPlace: data.place_of_birth || '',
            ageAtMigration: calculateAgeAtMigration(data.date_of_birth, data.migration?.date_of_arrival_nt),
            yearOfArrival: data.migration?.date_of_arrival_nt ? 
              new Date(data.migration.date_of_arrival_nt).getFullYear() : 0,
            regionOfOrigin: data.place_of_birth || 'Unknown',
            settlementLocation: data.residence?.town_or_city || 'Unknown',
            occupation: data.occupation || 'Unknown',
            deathDate: data.date_of_death || '',
            deathPlace: data.residence?.home_at_death || '',
            mainPhoto: '', // No photo URL in the API response
            biography: data.additional_notes || '',
            photos: [],
            relatedMigrants: []
          };
          
          setMigrant(migrantProfile);
          setError(null);
        } else {
          // No data found for this ID
          setMigrant(null);
          setError(`No migrant found with ID: ${id}`);
        }
      } catch (error: any) {
        // Handle API errors
        const errorMessage = 
          error.response?.data?.message || 
          error.message || 
          'An unexpected error occurred';
          
        console.error('Error fetching migrant:', errorMessage);
        setError(`Failed to load migrant data: ${errorMessage}`);
      } finally {
        setLoading(false);
      }
    };

    fetchMigrantData();
  }, [id, retryCount]); // retryCount allows manual retries

  // Handle retry button click
  const handleRetry = () => {
    setRetryCount(prev => prev + 1);
  };
  
  // Loading state
  if (loading) {
    return (
      <div className="flex flex-col items-center justify-center min-h-[60vh] p-8">
        <Loader2 className="h-12 w-12 animate-spin text-primary mb-4" />
        <h2 className="text-xl font-medium mb-2">Loading migrant profile...</h2>
        <p className="text-gray-500">Retrieving data from the database</p>
      </div>
    );
  }
  
  // Error state
  if (error) {
    // Check if the error is specifically about not finding a migrant
    const isNotFoundError = error.includes('No migrant found');
    
    return (
      <div className="max-w-3xl mx-auto p-8">
        <Alert variant={isNotFoundError ? "default" : "destructive"} className={`mb-6 ${isNotFoundError ? 'border-amber-500' : ''}`}>
          <AlertCircle className={`h-5 w-5 ${isNotFoundError ? 'text-amber-500' : ''}`} />
          <AlertTitle>{isNotFoundError ? "Migrant Not Found" : "Error"}</AlertTitle>
          <AlertDescription>{error}</AlertDescription>
        </Alert>
        
        <div className="flex flex-col items-center mt-8 mb-4">
          {isNotFoundError && (
            <div className="text-center mb-6">
              <p className="text-lg mb-4">The migrant profile you're looking for could not be found in our database.</p>
              <p className="text-gray-600">This might be because:</p>
              <ul className="list-disc list-inside text-gray-600 mt-2 mb-4">
                <li>The ID provided is incorrect</li>
                <li>The record has been removed from the database</li>
                <li>The record hasn't been added to the database yet</li>
              </ul>
            </div>
          )}
          
          <div className="flex gap-4 justify-center">
            <Button onClick={() => navigate(-1)}>Go Back</Button>
            {!isNotFoundError && (
              <Button variant="outline" onClick={handleRetry}>Retry</Button>
            )}
            <Button variant="outline" onClick={() => window.location.href = '/search-test'}>Search Again</Button>
          </div>
        </div>
      </div>
    );
  }

  // No data state (should be caught by error state, but just in case)
  if (!migrant) {
    return (
      <div className="max-w-3xl mx-auto p-8 text-center">
        <h2 className="text-2xl font-bold mb-4">Migrant Profile Not Found</h2>
        <p className="mb-6">The migrant profile you're looking for could not be found.</p>
        <Button onClick={() => navigate(-1)}>Return to Previous Page</Button>
      </div>
    );
  }

  // Render migrant profile when data is loaded successfully
  return <MigrantProfileComponent migrant={migrant} />;
};

export default MigrantProfilePage;