/**
 * HomeView Component
 * Client-side home page view with search and filtering
 */

'use client';

import { useState, useEffect, useRef } from 'react';
import { useSearchParams, useRouter, usePathname } from 'next/navigation';
import { FilterBar } from './FilterBar';
import { SchoolRow } from './SchoolRow';
import { SecondarySchoolRow } from './SecondarySchoolRow';
import { SchoolMap } from './SchoolMap';
import { EmptyState } from './EmptyState';
import { useComparisonContext } from '@/context/ComparisonContext';
import { fetchSchools, fetchLAaverages } from '@/lib/api';
import type { SchoolsResponse, Filters, School } from '@/lib/types';
import { schoolUrl } from '@/lib/utils';
import styles from './HomeView.module.css';

interface HomeViewProps {
  initialSchools: SchoolsResponse;
  filters: Filters;
  totalSchools?: number | null;
}

export function HomeView({ initialSchools, filters, totalSchools }: HomeViewProps) {
  const searchParams = useSearchParams();
  const router = useRouter();
  const pathname = usePathname();
  const { addSchool, removeSchool, selectedSchools } = useComparisonContext();
  const [resultsView, setResultsView] = useState<'list' | 'map'>('list');
  const [selectedMapSchool, setSelectedMapSchool] = useState<School | null>(null);
  const sortOrder = searchParams.get('sort') || 'default';
  const [allSchools, setAllSchools] = useState<School[]>(initialSchools.schools);
  const [currentPage, setCurrentPage] = useState(initialSchools.page);
  const [hasMore, setHasMore] = useState(initialSchools.total_pages > 1);
  const [isLoadingMore, setIsLoadingMore] = useState(false);
  const [laAverages, setLaAverages] = useState<Record<string, number>>({});
  const [mapSchools, setMapSchools] = useState<School[]>([]);
  const [isLoadingMap, setIsLoadingMap] = useState(false);
  const prevSearchParamsRef = useRef(searchParams.toString());

  const hasSearch = searchParams.get('search') || searchParams.get('postcode');
  const isLocationSearch = !!searchParams.get('postcode');
  const isSearchActive = !!(hasSearch || searchParams.get('local_authority') || searchParams.get('school_type'));
  const currentPhase = searchParams.get('phase') || '';
  const secondaryCount = allSchools.filter(s => s.attainment_8_score != null).length;
  const primaryCount = allSchools.filter(s => s.rwm_expected_pct != null).length;
  const isSecondaryView = currentPhase.toLowerCase().includes('secondary')
    || (!currentPhase && secondaryCount > primaryCount);
  const isMixedView = primaryCount > 0 && secondaryCount > 0 && !currentPhase;

  // Reset pagination state when search params change
  useEffect(() => {
    const newParamsStr = searchParams.toString();
    if (newParamsStr !== prevSearchParamsRef.current) {
      prevSearchParamsRef.current = newParamsStr;
      setAllSchools(initialSchools.schools);
      setCurrentPage(initialSchools.page);
      setHasMore(initialSchools.total_pages > 1);
      setMapSchools([]);
    }
  }, [searchParams, initialSchools]);

  // Close bottom sheet if we change views or search
  useEffect(() => {
    setSelectedMapSchool(null);
  }, [resultsView, searchParams]);

  // Fetch all schools within radius when map view is active
  useEffect(() => {
    if (resultsView !== 'map' || !isLocationSearch) return;
    setIsLoadingMap(true);
    const params: Record<string, any> = {};
    searchParams.forEach((value, key) => { params[key] = value; });
    params.page = 1;
    params.page_size = 500;
    fetchSchools(params, { cache: 'no-store' })
      .then(r => setMapSchools(r.schools))
      .catch(() => setMapSchools(initialSchools.schools))
      .finally(() => setIsLoadingMap(false));
  }, [resultsView, searchParams]);

  // Fetch LA averages when secondary or mixed schools are visible
  useEffect(() => {
    if (!isSecondaryView && !isMixedView) return;
    fetchLAaverages({ cache: 'force-cache' })
      .then(data => setLaAverages(data.secondary.attainment_8_by_la))
      .catch(() => {});
  }, [isSecondaryView, isMixedView]);

  const handleLoadMore = async () => {
    if (isLoadingMore || !hasMore) return;
    setIsLoadingMore(true);
    try {
      const params: Record<string, any> = {};
      searchParams.forEach((value, key) => { params[key] = value; });
      params.page = currentPage + 1;
      params.page_size = initialSchools.page_size;
      const response = await fetchSchools(params, { cache: 'no-store' });
      setAllSchools(prev => [...prev, ...response.schools]);
      setCurrentPage(response.page);
      setHasMore(response.page < response.total_pages);
    } catch {
      // silently ignore
    } finally {
      setIsLoadingMore(false);
    }
  };

  const sortedSchools = [...allSchools].sort((a, b) => {
    if (sortOrder === 'rwm_desc') return (b.rwm_expected_pct ?? -Infinity) - (a.rwm_expected_pct ?? -Infinity);
    if (sortOrder === 'rwm_asc') return (a.rwm_expected_pct ?? Infinity) - (b.rwm_expected_pct ?? Infinity);
    if (sortOrder === 'att8_desc') return (b.attainment_8_score ?? -Infinity) - (a.attainment_8_score ?? -Infinity);
    if (sortOrder === 'att8_asc') return (a.attainment_8_score ?? Infinity) - (b.attainment_8_score ?? Infinity);
    if (sortOrder === 'distance') return (a.distance ?? Infinity) - (b.distance ?? Infinity);
    if (sortOrder === 'name_asc') return a.school_name.localeCompare(b.school_name);
    return 0;
  });

  return (
    <div className={styles.homeView}>
      {/* Combined Hero + Search and Filters */}
      {!isSearchActive && (
        <div className={styles.heroSection}>
          <h1 className={styles.heroTitle}>Find Local Schools</h1>
          <p className={styles.heroDescription}>Compare school results (SATs and GCSE), for thousands of schools across England</p>
        </div>
      )}

      <FilterBar
        filters={filters}
        isHero={!isSearchActive}
        resultFilters={initialSchools.result_filters}
      />

      {/* Discovery section shown on landing page before any search */}
      {!isSearchActive && initialSchools.schools.length === 0 && (
        <div className={styles.discoverySection}>
          {totalSchools && <p className={styles.discoveryCount}><strong>{totalSchools.toLocaleString()}+</strong> primary and secondary schools across England</p>}
          <p className={styles.discoveryHints}>Try searching for a school name, or enter a postcode to find schools near you.</p>
          <div className={styles.quickSearches}>
            <span className={styles.quickSearchLabel}>Quick searches:</span>
            {['Manchester', 'Bristol', 'Leeds', 'Birmingham'].map(city => (
              <a key={city} href={`/?search=${city}`} className={styles.quickSearchChip}>{city}</a>
            ))}
          </div>
        </div>
      )}

      {/* Results Section */}
      <section className={`${styles.results} ${resultsView === 'map' && isLocationSearch ? styles.mapViewResults : ''}`}>
        {!hasSearch && initialSchools.schools.length > 0 && (
          <div className={styles.sectionHeader}>
            <h2>Featured Schools</h2>
            <p className={styles.sectionDescription}>
              Explore schools from across England
            </p>
          </div>
        )}

        {hasSearch && (
          <div className={styles.resultsHeader}>
            <h2 aria-live="polite" aria-atomic="true">
              {isLocationSearch && initialSchools.location_info
                ? `${initialSchools.total.toLocaleString()} school${initialSchools.total !== 1 ? 's' : ''} within ${(initialSchools.location_info.radius / 1.60934).toFixed(1)} miles of ${initialSchools.location_info.postcode}`
                : `${initialSchools.total.toLocaleString()} school${initialSchools.total !== 1 ? 's' : ''} found`
              }
            </h2>
            <div className={styles.resultsHeaderActions}>
              {isLocationSearch && initialSchools.schools.length > 0 && (
                <div className={styles.viewToggle}>
                  <button
                    className={`${styles.viewToggleBtn} ${resultsView === 'list' ? styles.active : ''}`}
                    onClick={() => setResultsView('list')}
                  >
                    <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" width="16" height="16">
                      <line x1="8" y1="6" x2="21" y2="6"/>
                      <line x1="8" y1="12" x2="21" y2="12"/>
                      <line x1="8" y1="18" x2="21" y2="18"/>
                      <line x1="3" y1="6" x2="3.01" y2="6"/>
                      <line x1="3" y1="12" x2="3.01" y2="12"/>
                      <line x1="3" y1="18" x2="3.01" y2="18"/>
                    </svg>
                    List
                  </button>
                  <button
                    className={`${styles.viewToggleBtn} ${resultsView === 'map' ? styles.active : ''}`}
                    onClick={() => setResultsView('map')}
                  >
                    <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" width="16" height="16">
                      <path d="M21 10c0 7-9 13-9 13s-9-6-9-13a9 9 0 0 1 18 0z"/>
                      <circle cx="12" cy="10" r="3"/>
                    </svg>
                    Map
                  </button>
                </div>
              )}
              {resultsView === 'list' && (
                <select
                  value={sortOrder}
                  onChange={e => {
                    const params = new URLSearchParams(searchParams);
                    if (e.target.value === 'default') {
                      params.delete('sort');
                    } else {
                      params.set('sort', e.target.value);
                    }
                    router.push(`${pathname}?${params.toString()}`);
                  }}
                  className={styles.sortSelect}
                >
                  <option value="default">Sort: Relevance</option>
                  {(!isSecondaryView || isMixedView) && <option value="rwm_desc">Highest R, W &amp; M %</option>}
                  {(!isSecondaryView || isMixedView) && <option value="rwm_asc">Lowest R, W &amp; M %</option>}
                  {(isSecondaryView || isMixedView) && <option value="att8_desc">Highest Attainment 8</option>}
                  {(isSecondaryView || isMixedView) && <option value="att8_asc">Lowest Attainment 8</option>}
                  {isLocationSearch && <option value="distance">Nearest first</option>}
                  <option value="name_asc">Name A–Z</option>
                </select>
              )}
            </div>
          </div>
        )}

        {isSearchActive && (
          <div className={styles.activeFilters}>
            {searchParams.get('search') && <span className={styles.filterChip}>Search: {searchParams.get('search')}<a href="/" className={styles.chipRemove} onClick={e => { e.preventDefault(); }}>×</a></span>}
            {searchParams.get('local_authority') && <span className={styles.filterChip}>{searchParams.get('local_authority')}</span>}
            {searchParams.get('school_type') && <span className={styles.filterChip}>{searchParams.get('school_type')}</span>}
          </div>
        )}

        {initialSchools.schools.length === 0 && isSearchActive ? (
          <EmptyState
            title="No schools found"
            message="Try adjusting your search criteria or filters to find schools."
            action={{
              label: 'Clear all filters',
              onClick: () => {
                window.location.href = '/';
              },
            }}
          />
        ) : initialSchools.schools.length > 0 && resultsView === 'map' && isLocationSearch ? (
          /* Map View Layout */
          <div className={styles.mapViewContainer}>
            <div className={styles.mapContainer}>
              <SchoolMap
                schools={isLoadingMap ? initialSchools.schools : mapSchools}
                center={initialSchools.location_info?.coordinates}
                referencePoint={initialSchools.location_info?.coordinates}
                onMarkerClick={setSelectedMapSchool}
              />
            </div>
            <div className={styles.compactList}>
              {(isLoadingMap ? initialSchools.schools : mapSchools).map((school) => (
                <div
                  key={school.urn}
                  className={`${styles.listItemWrapper} ${selectedMapSchool?.urn === school.urn ? styles.highlightedItem : ''}`}
                >
                  <CompactSchoolItem
                    school={school}
                    onAddToCompare={addSchool}
                    isInCompare={selectedSchools.some(s => s.urn === school.urn)}
                  />
                </div>
              ))}
            </div>

            {/* Mobile Bottom Sheet for Selected Map Pin */}
            {selectedMapSchool && (
              <div className={styles.bottomSheetWrapper}>
                <div className={styles.bottomSheet}>
                  <button className={styles.closeSheetBtn} onClick={() => setSelectedMapSchool(null)}>×</button>
                  <CompactSchoolItem
                    school={selectedMapSchool}
                    onAddToCompare={addSchool}
                    isInCompare={selectedSchools.some(s => s.urn === selectedMapSchool.urn)}
                  />
                </div>
              </div>
            )}
          </div>
        ) : (
          /* List View Layout */
          <>
            <div className={styles.schoolList}>
              {sortedSchools.map((school) => (
                school.attainment_8_score != null ? (
                  <SecondarySchoolRow
                    key={school.urn}
                    school={school}
                    isLocationSearch={isLocationSearch}
                    onAddToCompare={addSchool}
                    onRemoveFromCompare={removeSchool}
                    isInCompare={selectedSchools.some(s => s.urn === school.urn)}
                    laAvgAttainment8={school.local_authority ? laAverages[school.local_authority] ?? null : null}
                  />
                ) : (
                  <SchoolRow
                    key={school.urn}
                    school={school}
                    isLocationSearch={isLocationSearch}
                    onAddToCompare={addSchool}
                    onRemoveFromCompare={removeSchool}
                    isInCompare={selectedSchools.some(s => s.urn === school.urn)}
                  />
                )
              ))}
            </div>

            {(hasMore || allSchools.length < initialSchools.total) && (
              <div className={styles.loadMoreSection}>
                <p className={styles.loadMoreCount}>
                  Showing {allSchools.length.toLocaleString()} of {initialSchools.total.toLocaleString()} schools
                </p>
                {hasMore && (
                  <button
                    onClick={handleLoadMore}
                    disabled={isLoadingMore}
                    className={`btn btn-secondary ${styles.loadMoreButton}`}
                  >
                    {isLoadingMore ? 'Loading...' : 'Load more schools'}
                  </button>
                )}
              </div>
            )}
          </>
        )}
      </section>
    </div>
  );
}

/* Compact School Item for Map View */
interface CompactSchoolItemProps {
  school: School;
  onAddToCompare: (school: School) => void;
  isInCompare: boolean;
}

function CompactSchoolItem({ school, onAddToCompare, isInCompare }: CompactSchoolItemProps) {
  return (
    <div className={styles.compactItem}>
      <div className={styles.compactItemContent}>
        <div className={styles.compactItemHeader}>
          <a href={schoolUrl(school.urn, school.school_name)} className={styles.compactItemName}>
            {school.school_name}
          </a>
          {school.distance !== undefined && school.distance !== null && (
            <span className={styles.distanceBadge}>
              {school.distance.toFixed(1)} mi
            </span>
          )}
        </div>
        <div className={styles.compactItemMeta}>
          {school.school_type && <span>{school.school_type}</span>}
          {school.local_authority && <span>{school.local_authority}</span>}
        </div>
        <div className={styles.compactItemStats}>
          <span className={styles.compactStat}>
            <strong>
              {school.attainment_8_score != null
                ? school.attainment_8_score.toFixed(1)
                : school.rwm_expected_pct !== null
                  ? `${school.rwm_expected_pct}%`
                  : '-'}
            </strong>{' '}
            {school.attainment_8_score != null ? 'Att 8' : 'RWM'}
          </span>
          <span className={styles.compactStat}>
            <strong>{school.total_pupils || '-'}</strong> pupils
          </span>
        </div>
      </div>
      <div className={styles.compactItemActions}>
        <button
          className={isInCompare ? 'btn btn-active btn-sm' : 'btn btn-secondary btn-sm'}
          onClick={() => onAddToCompare(school)}
        >
          {isInCompare ? '✓ Comparing' : '+ Compare'}
        </button>
        <a href={schoolUrl(school.urn, school.school_name)} className="btn btn-tertiary btn-sm">
          View
        </a>
      </div>
    </div>
  );
}