import React, { useState, useEffect } from 'react';
import { UmbrellaIcon, SnowflakeIcon, SunIcon, WindIcon, AlertTriangleIcon } from '../components/icons';
import { useLocalStorage } from '../hooks/useLocalStorage';
import type { BonsaiTree } from '../types';
import Spinner from '../components/Spinner';

interface WeatherData {
    daily: {
        time: string[];
        weathercode: number[];
        temperature_2m_max: number[];
        temperature_2m_min: number[];
        windspeed_10m_max: number[];
    };
}

const WeatherShieldView: React.FC = () => {
    const [trees] = useLocalStorage<BonsaiTree[]>('bonsai-diary-trees', []);
    const [weather, setWeather] = useState<WeatherData | null>(null);
    const [isLoading, setIsLoading] = useState(true);
    const [error, setError] = useState<string>('');

    useEffect(() => {
        const fetchWeather = async () => {
            if (trees.length === 0) {
                setIsLoading(false);
                return;
            }
            
            // For simplicity, use the location of the first tree as the primary location
            const primaryLocation = trees[0].location;
            if (!primaryLocation) {
                setError("No location set for your trees. Please add a location in 'My Garden'.");
                setIsLoading(false);
                return;
            }

            try {
                // Simple geocoding using a public API
                const geoResponse = await fetch(`https://geocoding-api.open-meteo.com/v1/search?name=${encodeURIComponent(primaryLocation)}&count=1`);
                const geoData = await geoResponse.json();

                if (!geoData.results || geoData.results.length === 0) {
                    throw new Error(`Could not find location: ${primaryLocation}`);
                }
                const { latitude, longitude } = geoData.results[0];
                
                // Fetch weather forecast
                const weatherResponse = await fetch(`https://api.open-meteo.com/v1/forecast?latitude=${latitude}&longitude=${longitude}&daily=weathercode,temperature_2m_max,temperature_2m_min,windspeed_10m_max&timezone=auto`);
                const weatherData = await weatherResponse.json();
                setWeather(weatherData);

            } catch (err) {
                 if (err instanceof Error) {
                    setError(`Failed to fetch weather data: ${err.message}`);
                } else {
                    setError("An unknown error occurred while fetching weather data.");
                }
            } finally {
                setIsLoading(false);
            }
        };

        fetchWeather();
    }, [trees]);
    
    const getWeatherIcon = (code: number) => {
        if (code >= 200 && code < 600) return <UmbrellaIcon className="w-8 h-8 text-blue-500" />; // Rain
        if (code >= 600 && code < 700) return <SnowflakeIcon className="w-8 h-8 text-cyan-400" />; // Snow
        if (code === 800) return <SunIcon className="w-8 h-8 text-yellow-500" />; // Clear
        return <SunIcon className="w-8 h-8 text-stone-500" />; // Default/Clouds
    };

    const generateAlertsForTree = (tree: BonsaiTree) => {
        if (!weather || !tree.protectionProfile || !tree.protectionProfile.alertsEnabled) return [];
        
        const alerts: string[] = [];
        weather.daily.time.slice(0, 5).forEach((_, i) => {
            const dayMinTemp = weather.daily.temperature_2m_min[i];
            const dayMaxTemp = weather.daily.temperature_2m_max[i];
            const dayMaxWind = weather.daily.windspeed_10m_max[i];

            if (dayMinTemp < tree.protectionProfile!.minTempC) {
                alerts.push(`Frost Alert for ${new Date(weather.daily.time[i]).toLocaleDateString([], {weekday: 'short'})}: Low of ${dayMinTemp.toFixed(0)}°C`);
            }
            if (dayMaxTemp > tree.protectionProfile!.maxTempC) {
                alerts.push(`Heat Alert for ${new Date(weather.daily.time[i]).toLocaleDateString([], {weekday: 'short'})}: High of ${dayMaxTemp.toFixed(0)}°C`);
            }
            if (dayMaxWind > tree.protectionProfile!.maxWindKph) {
                alerts.push(`Wind Alert for ${new Date(weather.daily.time[i]).toLocaleDateString([], {weekday: 'short'})}: Gusts up to ${dayMaxWind.toFixed(0)} km/h`);
            }
        });
        return alerts;
    }


    return (
        <div className="space-y-8 max-w-6xl mx-auto">
            <header className="text-center">
                <h2 className="text-3xl font-bold tracking-tight text-stone-900 sm:text-4xl flex items-center justify-center gap-3">
                    <UmbrellaIcon className="w-8 h-8 text-blue-600" />
                    Weather Shield
                </h2>
                <p className="mt-4 text-lg leading-8 text-stone-600">
                    Proactive weather alerts for your bonsai collection, based on their individual needs.
                </p>
            </header>

            {isLoading ? <Spinner text="Fetching local forecast..."/> : 
             error ? <p className="text-center text-red-600 p-4 bg-red-50 rounded-md">{error}</p> :
             !weather ? <p className="text-center text-stone-600">Add trees to your garden to see weather alerts.</p> :
            (
                <>
                <div className="bg-white p-6 rounded-xl shadow-lg border border-stone-200">
                    <h3 className="text-xl font-bold text-stone-800 mb-4">5-Day Forecast for {trees[0]?.location || 'Your Area'}</h3>
                    <div className="grid grid-cols-2 md:grid-cols-5 gap-4 text-center">
                        {weather.daily.time.slice(0, 5).map((time, i) => (
                             <div key={time} className="bg-stone-50 p-4 rounded-lg border border-stone-100">
                                <p className="font-bold text-stone-900">{new Date(time).toLocaleDateString([], { weekday: 'short', day: 'numeric'})}</p>
                                <div className="my-2">{getWeatherIcon(weather.daily.weathercode[i])}</div>
                                <p className="font-semibold text-blue-600">{weather.daily.temperature_2m_min[i].toFixed(0)}°C</p>
                                <p className="font-semibold text-red-600">{weather.daily.temperature_2m_max[i].toFixed(0)}°C</p>
                                <p className="text-sm text-stone-500 mt-1 flex items-center justify-center gap-1"><WindIcon className="w-4 h-4" />{weather.daily.windspeed_10m_max[i].toFixed(0)} km/h</p>
                             </div>
                        ))}
                    </div>
                </div>

                <div className="space-y-4">
                    <h3 className="text-xl font-bold text-stone-800">Tree Protection Status</h3>
                    {trees.map(tree => {
                        const alerts = generateAlertsForTree(tree);
                        const hasAlerts = alerts.length > 0;
                        return (
                             <div key={tree.id} className={`bg-white p-4 rounded-lg shadow-md border-l-4 ${hasAlerts ? 'border-red-500' : 'border-green-500'}`}>
                                <h4 className="font-bold text-lg text-stone-900">{tree.name} <span className="text-sm font-normal text-stone-500">({tree.species})</span></h4>
                                {hasAlerts ? (
                                    <div className="mt-2 space-y-1">
                                        {alerts.map((alert, i) => (
                                            <div key={i} className="flex items-center gap-2 text-sm text-red-700 font-semibold">
                                                <AlertTriangleIcon className="w-4 h-4 flex-shrink-0" />
                                                <p>{alert}</p>
                                            </div>
                                        ))}
                                    </div>
                                ) : (
                                    <p className="mt-1 text-sm text-green-700 font-medium">No weather threats detected in the next 5 days.</p>
                                )}
                             </div>
                        );
                    })}
                </div>
                </>
            )
            }
        </div>
    );
};

export default WeatherShieldView;