<?php

namespace App\Services;

use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Log;

class WeatherService
{
    /**
     * Get weather data for a given location string.
     */
    public function getWeather(string $location): array
    {
        $cacheKey = 'weather_' . md5($location);

        return Cache::remember($cacheKey, 3600, function () use ($location) {
            try {
                $coords = $this->geocode($location);
                if (!$coords) {
                    return $this->getFallbackWeather($location);
                }

                $response = Http::withHeaders([
                    'User-Agent' => 'GSB-Dashboard/1.0'
                ])->get('https://api.open-meteo.com/v1/forecast', [
                    'latitude' => $coords['lat'],
                    'longitude' => $coords['lon'],
                    'current_weather' => true,
                    'daily' => 'temperature_2m_max,temperature_2m_min',
                    'temperature_unit' => 'fahrenheit',
                    'wind_speed_unit' => 'mph',
                    'timezone' => 'auto'
                ]);

                if ($response->failed()) {
                    return $this->getFallbackWeather($location);
                }

                $data = $response->json();
                $current = $data['current_weather'] ?? null;
                $daily = $data['daily'] ?? null;

                if (!$current) {
                    return $this->getFallbackWeather($location);
                }

                $code = $current['weathercode'] ?? 0;
                $weatherDetails = $this->interpretWeatherCode($code);

                return [
                    'condition' => $weatherDetails['condition'],
                    'temp' => round($current['temperature']) . '°F',
                    'high' => isset($daily['temperature_2m_max'][0]) ? round($daily['temperature_2m_max'][0]) . '°F' : 'N/A',
                    'low' => isset($daily['temperature_2m_min'][0]) ? round($daily['temperature_2m_min'][0]) . '°F' : 'N/A',
                    'forecast' => sprintf(
                        '%s. Winds at %s mph. Source: Live API.',
                        $weatherDetails['forecast'],
                        round($current['windspeed'])
                    ),
                    'color' => $weatherDetails['color']
                ];
            } catch (\Exception $e) {
                Log::warning('Weather API failed: ' . $e->getMessage());
                return $this->getFallbackWeather($location);
            }
        });
    }

    /**
     * Geocode a location string to coordinates using cache and OSM Nominatim.
     */
    private function geocode(string $location): ?array
    {
        $cacheKey = 'coords_' . md5($location);

        return Cache::remember($cacheKey, 86400 * 30, function () use ($location) {
            // Check major pre-defined keywords
            $lowLoc = strtolower($location);
            $presetCities = [
                'new york' => ['lat' => 40.7128, 'lon' => -74.0060],
                'san francisco' => ['lat' => 37.7749, 'lon' => -122.4194],
                'chicago' => ['lat' => 41.8781, 'lon' => -87.6298],
                'los angeles' => ['lat' => 34.0522, 'lon' => -118.2437],
                'london' => ['lat' => 51.5074, 'lon' => -0.1278],
                'tokyo' => ['lat' => 35.6762, 'lon' => 139.6503],
                'paris' => ['lat' => 48.8566, 'lon' => 2.3522],
                'berlin' => ['lat' => 52.5200, 'lon' => 13.4050],
                'istanbul' => ['lat' => 41.0082, 'lon' => 28.9784],
            ];

            foreach ($presetCities as $city => $coords) {
                if (str_contains($lowLoc, $city)) {
                    return $coords;
                }
            }

            try {
                // Call OSM Nominatim API with descriptive User-Agent
                $response = Http::withHeaders([
                    'User-Agent' => 'GSB-Construction-Management-System/1.0 (admin@example.com)'
                ])->timeout(3)->get('https://nominatim.openstreetmap.org/search', [
                    'q' => $location,
                    'format' => 'json',
                    'limit' => 1
                ]);

                if ($response->successful() && !empty($response->json())) {
                    $first = $response->json()[0];
                    return [
                        'lat' => (float)$first['lat'],
                        'lon' => (float)$first['lon']
                    ];
                }
            } catch (\Exception $e) {
                Log::warning('Geocoding request failed: ' . $e->getMessage());
            }

            return null;
        });
    }

    /**
     * Map WMO weather code to condition, forecast description, and color class.
     */
    private function interpretWeatherCode(int $code): array
    {
        return match ($code) {
            0 => [
                'condition' => 'Clear Sky',
                'forecast' => 'Clear, sunny day. Ideal for outdoor operations',
                'color' => 'emerald'
            ],
            1, 2, 3 => [
                'condition' => 'Partly Cloudy',
                'forecast' => 'Mainly clear with some passing clouds',
                'color' => 'blue'
            ],
            45, 48 => [
                'condition' => 'Foggy',
                'forecast' => 'Visibility reduced. Exercise caution on elevated works',
                'color' => 'amber'
            ],
            51, 53, 55, 56, 57 => [
                'condition' => 'Drizzle',
                'forecast' => 'Light drizzle expected. Watch out for slippery surfaces',
                'color' => 'blue'
            ],
            61, 63, 65, 66, 67, 80, 81, 82 => [
                'condition' => 'Rainy',
                'forecast' => 'Moderate to heavy rain. Some outdoor concrete works may be delayed',
                'color' => 'blue'
            ],
            71, 73, 75, 77, 85, 86 => [
                'condition' => 'Snowing',
                'forecast' => 'Snowfall expected. Keep pathways clear and check structural loads',
                'color' => 'sky'
            ],
            95, 96, 99 => [
                'condition' => 'Thunderstorm',
                'forecast' => 'Thunderstorms expected. High risk for crane operations. Stop high works',
                'color' => 'amber'
            ],
            default => [
                'condition' => 'Scattered Clouds',
                'forecast' => 'Generally favorable working conditions',
                'color' => 'emerald'
            ]
        };
    }

    /**
     * Fallback mock weather generation based on location hash so it's stable but responsive.
     */
    private function getFallbackWeather(string $location): array
    {
        $hash = crc32($location);
        $tempBase = 65 + ($hash % 25); // 65 to 90
        $high = $tempBase + 5;
        $low = $tempBase - 10;

        $conditions = [
            ['condition' => 'Sunny / Clear', 'forecast' => 'Clear weather. Ideal for all site work.', 'color' => 'emerald'],
            ['condition' => 'Partly Cloudy', 'forecast' => 'Partly cloudy. Good working conditions.', 'color' => 'blue'],
            ['condition' => 'Overcast', 'forecast' => 'Overcast skies. Outdoor activities normal.', 'color' => 'blue'],
            ['condition' => 'Light Rain', 'forecast' => 'Damp conditions. Caution on structural scaffolding.', 'color' => 'blue'],
            ['condition' => 'Scattered Thunderstorms', 'forecast' => 'Thunderstorms nearby. Secure tower cranes.', 'color' => 'amber'],
        ];

        $selected = $conditions[$hash % count($conditions)];

        return [
            'condition' => $selected['condition'],
            'temp' => $tempBase . '°F',
            'high' => $high . '°F',
            'low' => $low . '°F',
            'forecast' => $selected['forecast'] . ' (Offline Mode)',
            'color' => $selected['color']
        ];
    }
}