import { useState, useCallback, useEffect } from 'react';
import useEmblaCarousel from 'embla-carousel-react';
import { ExternalLink, Bed, Maximize2, PoundSterling, Clock, Building, Footprints, Bike, Train } from 'lucide-react';
import { Button } from './ui/button';
import type { PropertyProperties, POIDistanceInfo, POI } from '@/types';
import { formatDate, formatDuration } from '@/utils/format';

function TravelModeIcon({ mode }: { mode: string }) {
    switch (mode) {
        case 'WALK': return <Footprints className="h-3 w-3" />;
        case 'BICYCLE': return <Bike className="h-3 w-3" />;
        case 'TRANSIT': return <Train className="h-3 w-3" />;
        default: return null;
    }
}

function POIDistanceBadges({ distances }: { distances: POIDistanceInfo[] }) {
    if (!distances || distances.length === 0) return null;

    // Group by POI name
    const byPoi = new Map<string, POIDistanceInfo[]>();
    for (const d of distances) {
        const existing = byPoi.get(d.poi_name) || [];
        existing.push(d);
        byPoi.set(d.poi_name, existing);
    }

    return (
        <div className="flex flex-wrap gap-1.5 mt-1.5">
            {Array.from(byPoi.entries()).map(([poiName, dists]) => (
                <div key={poiName} className="flex items-center gap-1 text-xs text-muted-foreground bg-muted/50 px-1.5 py-0.5 rounded">
                    <span className="font-medium">{poiName}:</span>
                    {dists.map(d => (
                        <span key={d.travel_mode} className="flex items-center gap-0.5" title={`${d.travel_mode} to ${poiName}`}>
                            <TravelModeIcon mode={d.travel_mode} />
                            {formatDuration(d.duration_seconds)}
                        </span>
                    ))}
                </div>
            ))}
        </div>
    );
}

const TRAVEL_MODES: Array<'WALK' | 'BICYCLE' | 'TRANSIT'> = ['WALK', 'BICYCLE', 'TRANSIT'];

function AllPOIDistances({ pois, distances }: { pois: POI[]; distances?: POIDistanceInfo[] }) {
    // Index distances by poi_id + travel_mode for O(1) lookup
    const distMap = new Map<string, POIDistanceInfo>();
    if (distances) {
        for (const d of distances) {
            distMap.set(`${d.poi_id}_${d.travel_mode}`, d);
        }
    }

    return (
        <div className="flex flex-wrap gap-1.5 mt-1.5">
            {pois.map(poi => (
                <div key={poi.id} className="flex items-center gap-1 text-xs text-muted-foreground bg-muted/50 px-1.5 py-0.5 rounded">
                    <span className="font-medium">{poi.name}:</span>
                    {TRAVEL_MODES.map(mode => {
                        const dist = distMap.get(`${poi.id}_${mode}`);
                        return (
                            <span key={mode} className="flex items-center gap-0.5" title={`${mode} to ${poi.name}`}>
                                <TravelModeIcon mode={mode} />
                                {dist ? formatDuration(dist.duration_seconds) : '—'}
                            </span>
                        );
                    })}
                </div>
            ))}
        </div>
    );
}

function CardCarousel({ photos, altText }: { photos: string[]; altText?: string }) {
    const [emblaRef, emblaApi] = useEmblaCarousel({ loop: true });
    const [selectedIndex, setSelectedIndex] = useState(0);

    const onSelect = useCallback(() => {
        if (!emblaApi) return;
        setSelectedIndex(emblaApi.selectedScrollSnap());
    }, [emblaApi]);

    useEffect(() => {
        if (!emblaApi) return;
        emblaApi.on('select', onSelect);
        return () => { emblaApi.off('select', onSelect); };
    }, [emblaApi, onSelect]);

    if (photos.length <= 1) {
        return (
            <img
                src={photos[0]}
                alt={altText || "Property"}
                className="w-full h-full object-cover"
                loading="lazy"
            />
        );
    }

    return (
        <div className="relative w-full h-full" onClick={e => e.stopPropagation()}>
            <div className="overflow-hidden h-full" ref={emblaRef}>
                <div className="flex h-full">
                    {photos.map((url, i) => (
                        <div key={i} className="flex-[0_0_100%] min-w-0 h-full">
                            <img
                                src={url}
                                alt={`Property photo ${i + 1}`}
                                className="w-full h-full object-cover"
                                loading="lazy"
                            />
                        </div>
                    ))}
                </div>
            </div>
            <div className="absolute bottom-1 left-0 right-0 flex justify-center gap-1">
                {photos.map((_, i) => (
                    <div
                        key={i}
                        className={`w-1 h-1 rounded-full ${
                            i === selectedIndex ? 'bg-white' : 'bg-white/40'
                        }`}
                    />
                ))}
            </div>
        </div>
    );
}

interface PropertyCardProps {
    property: PropertyProperties;
    variant?: 'compact' | 'full';
    isHighlighted?: boolean;
    avgPricePerSqm?: number;
    allPOIs?: POI[];
    onClick?: () => void;
}

export function PropertyCard({
    property,
    variant = 'compact',
    isHighlighted = false,
    avgPricePerSqm,
    allPOIs,
    onClick,
}: PropertyCardProps) {
    const lastSeenDate = property.last_seen.split('T')[0];
    const lastSeenDays = Math.round((Date.now() - new Date(lastSeenDate).getTime()) / (1000 * 60 * 60 * 24));

    // Determine if this is a good deal
    const isGoodDeal = avgPricePerSqm && property.qmprice > 0 && property.qmprice < avgPricePerSqm * 0.9;
    const isExpensive = avgPricePerSqm && property.qmprice > avgPricePerSqm * 1.1;

    const priceIndicator = isGoodDeal
        ? { color: 'text-green-600 bg-green-50', label: 'Good deal' }
        : isExpensive
            ? { color: 'text-red-600 bg-red-50', label: 'Above avg' }
            : null;

    const handleClick = () => {
        onClick?.();
    };

    if (variant === 'compact') {
        return (
            <div
                className={`flex gap-3 p-3 rounded-lg border transition-colors cursor-pointer hover:bg-muted/50 ${
                    isHighlighted ? 'ring-2 ring-primary bg-primary/5' : ''
                }`}
                onClick={handleClick}
            >
                {/* Photo carousel */}
                <div className="w-24 h-24 rounded-md overflow-hidden flex-shrink-0 bg-muted">
                    {(property.photos?.length || property.photo_thumbnail) ? (
                        <CardCarousel
                            photos={property.photos?.length ? property.photos : [property.photo_thumbnail]}
                            altText={`${property.rooms}-bed, ${property.qm}m², £${property.total_price.toLocaleString()}`}
                        />
                    ) : null}
                </div>

                {/* Details */}
                <div className="flex-1 min-w-0">
                    <div className="flex items-start justify-between gap-2">
                        <div className="font-semibold text-base truncate">
                            £{property.total_price.toLocaleString()}
                            {property.listing_type !== 'BUY' && (
                                <span className="text-muted-foreground font-normal text-sm">/mo</span>
                            )}
                        </div>
                        {priceIndicator && (
                            <span className={`text-xs px-1.5 py-0.5 rounded ${priceIndicator.color}`}>
                                {priceIndicator.label}
                            </span>
                        )}
                    </div>

                    <div className="flex items-center gap-3 mt-1 text-sm text-muted-foreground">
                        <span className="flex items-center gap-1">
                            <Bed className="h-3.5 w-3.5" />
                            {property.rooms}
                        </span>
                        <span className="flex items-center gap-1">
                            <Maximize2 className="h-3.5 w-3.5" />
                            {property.qm} m²
                        </span>
                        <span className="flex items-center gap-1">
                            £{property.qmprice}/m²
                        </span>
                    </div>

                    <div className="flex items-center gap-2 mt-1 text-xs text-muted-foreground">
                        <span className="flex items-center gap-1">
                            <Clock className="h-3 w-3" />
                            {lastSeenDays}d ago
                        </span>
                        <span className="truncate">{property.agency}</span>
                    </div>
                    <POIDistanceBadges distances={property.poi_distances || []} />
                </div>
            </div>
        );
    }

    // Full variant (for popup/detail view)
    return (
        <div className={`p-4 border rounded-lg ${isHighlighted ? 'ring-2 ring-primary' : ''}`}>
            {/* Header with image and price */}
            <div className="flex gap-4">
                <a
                    href={property.url}
                    target="_blank"
                    rel="noopener noreferrer"
                    className="block w-32 h-24 rounded-md overflow-hidden flex-shrink-0 bg-muted hover:opacity-90 transition-opacity"
                >
                    {property.photo_thumbnail && (
                        <img
                            src={property.photo_thumbnail}
                            alt={`${property.rooms}-bed, ${property.qm}m², £${property.total_price.toLocaleString()}`}
                            className="w-full h-full object-cover"
                        />
                    )}
                </a>

                <div className="flex-1">
                    <div className="flex items-start justify-between">
                        <div>
                            <div className="font-semibold text-xl">
                                £{property.total_price.toLocaleString()}
                                {property.listing_type !== 'BUY' && (
                                    <span className="text-muted-foreground font-normal text-sm">/mo</span>
                                )}
                            </div>
                            {priceIndicator && (
                                <span className={`inline-block mt-1 text-xs px-2 py-0.5 rounded ${priceIndicator.color}`}>
                                    {priceIndicator.label}
                                </span>
                            )}
                        </div>
                    </div>
                </div>
            </div>

            {/* Stats grid */}
            <div className="grid grid-cols-2 gap-3 mt-4">
                <div className="flex items-center gap-2 text-sm">
                    <Bed className="h-4 w-4 text-muted-foreground" />
                    <span><strong>{property.rooms}</strong> bedrooms</span>
                </div>
                <div className="flex items-center gap-2 text-sm">
                    <Maximize2 className="h-4 w-4 text-muted-foreground" />
                    <span><strong>{property.qm}</strong> m²</span>
                </div>
                <div className="flex items-center gap-2 text-sm">
                    <PoundSterling className="h-4 w-4 text-muted-foreground" />
                    <span><strong>£{property.qmprice}</strong>/m²</span>
                </div>
                {property.listing_type !== 'BUY' && property.available_from && (
                    <div className="flex items-center gap-2 text-sm">
                        <Clock className="h-4 w-4 text-muted-foreground" />
                        <span>Available <strong>{formatDate(property.available_from)}</strong></span>
                    </div>
                )}
                {property.listing_type === 'BUY' && (
                    <div className="flex items-center gap-2 text-sm">
                        <Clock className="h-4 w-4 text-muted-foreground" />
                        <span>Seen <strong>{lastSeenDays}d</strong> ago</span>
                    </div>
                )}
            </div>

            {/* Agency and last seen */}
            <div className="flex items-center gap-2 mt-3 text-sm text-muted-foreground">
                <Building className="h-4 w-4" />
                <span>{property.agency}</span>
                <span className="mx-1">•</span>
                <span>Seen {lastSeenDays} days ago</span>
            </div>

            {/* POI Distances */}
            {allPOIs && allPOIs.length > 0 ? (
                <div className="mt-3 pt-3 border-t">
                    <div className="text-xs font-medium text-muted-foreground mb-1">Travel times</div>
                    <AllPOIDistances pois={allPOIs} distances={property.poi_distances} />
                </div>
            ) : property.poi_distances && property.poi_distances.length > 0 ? (
                <div className="mt-3 pt-3 border-t">
                    <div className="text-xs font-medium text-muted-foreground mb-1">Travel times</div>
                    <POIDistanceBadges distances={property.poi_distances} />
                </div>
            ) : null}

            {/* Price history */}
            {property.price_history.length > 1 && (
                <div className="mt-3 pt-3 border-t">
                    <div className="text-xs font-medium text-muted-foreground mb-1">Price history</div>
                    <div className="space-y-0.5">
                        {property.price_history.slice(0, 5).map((entry) => (
                            <div key={entry.id} className="text-sm flex justify-between">
                                <span className="text-muted-foreground">{entry.last_seen.split('T')[0]}</span>
                                <span>£{entry.price.toLocaleString()}</span>
                            </div>
                        ))}
                    </div>
                </div>
            )}

            {/* Actions */}
            <div className="mt-4">
                <Button asChild className="w-full">
                    <a href={property.url} target="_blank" rel="noopener noreferrer">
                        View Listing
                        <ExternalLink className="ml-2 h-4 w-4" />
                    </a>
                </Button>
            </div>
        </div>
    );
}