<?php

namespace App\Services;

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

class WeatherService
{
    private const BASE_SHORT = 'https://apis.data.go.kr/1360000/VilageFcstInfoService_2.0/getVilageFcst';

    private const BASE_MID_TA = 'https://apis.data.go.kr/1360000/MidFcstInfoService/getMidTa';

    private const BASE_MID_LAND = 'https://apis.data.go.kr/1360000/MidFcstInfoService/getMidLandFcst';

    // 서울 격자 좌표
    private const NX = 60;

    private const NY = 127;

    // 중기예보 지역 코드 (서울)
    private const MID_TA_REG_ID = '11B10101';   // 서울 기온

    private const MID_LAND_REG_ID = '11B00000';  // 서울·인천·경기

    private string $serviceKey;

    public function __construct()
    {
        $this->serviceKey = config('services.kma.service_key', '');
    }

    /**
     * 7일 예보 데이터 반환 (3시간 캐시)
     */
    public function getWeeklyForecast(): array
    {
        if (empty($this->serviceKey)) {
            return [];
        }

        return Cache::remember('weather_forecast_7days', 10800, function () {
            try {
                return $this->buildForecast();
            } catch (\Throwable $e) {
                Log::warning('WeatherService: 예보 조합 실패', ['error' => $e->getMessage()]);

                return [];
            }
        });
    }

    private function buildForecast(): array
    {
        $today = Carbon::today();
        $forecasts = [];

        // 1) 단기예보 (오늘 ~ +2일, 최대 3일)
        $short = $this->fetchShortForecast();
        foreach ($short as $date => $data) {
            $forecasts[$date] = $data;
        }

        // 2) 중기기온 + 중기날씨 (3일 ~ 7일)
        $midTa = $this->fetchMidTemperature();
        $midLand = $this->fetchMidLandForecast();

        for ($i = 3; $i <= 7; $i++) {
            $date = $today->copy()->addDays($i)->format('Ymd');
            $forecasts[$date] = [
                'date' => $date,
                'tmn' => $midTa["taMin{$i}"] ?? null,
                'tmx' => $midTa["taMax{$i}"] ?? null,
                'icon' => $this->midWeatherToIcon($midLand["wf{$i}Am"] ?? ($midLand["wf{$i}"] ?? '')),
            ];
        }

        // 날짜순 정렬 후 7일만
        ksort($forecasts);

        return array_slice(array_values($forecasts), 0, 7);
    }

    /**
     * 단기예보 API 호출 — TMN/TMX/SKY/PTY 추출
     */
    private function fetchShortForecast(): array
    {
        $now = Carbon::now();
        // base_date: 오늘, base_time: 0200 (02시 발표 → TMN/TMX 포함)
        $baseDate = $now->hour < 2 ? $now->copy()->subDay()->format('Ymd') : $now->format('Ymd');
        $baseTime = '0200';

        $response = Http::timeout(10)->get(self::BASE_SHORT, [
            'serviceKey' => $this->serviceKey,
            'pageNo' => 1,
            'numOfRows' => 1000,
            'dataType' => 'JSON',
            'base_date' => $baseDate,
            'base_time' => $baseTime,
            'nx' => self::NX,
            'ny' => self::NY,
        ]);

        if (! $response->successful()) {
            Log::warning('WeatherService: 단기예보 API 실패', ['status' => $response->status()]);

            return [];
        }

        $body = $response->json();
        $items = data_get($body, 'response.body.items.item', []);

        if (empty($items)) {
            return [];
        }

        // 날짜별 그룹
        $grouped = [];
        foreach ($items as $item) {
            $fcstDate = $item['fcstDate'];
            $category = $item['category'];
            $value = $item['fcstValue'];

            if (! isset($grouped[$fcstDate])) {
                $grouped[$fcstDate] = ['date' => $fcstDate, 'tmn' => null, 'tmx' => null, 'sky' => null, 'pty' => null];
            }

            match ($category) {
                'TMN' => $grouped[$fcstDate]['tmn'] = (int) $value,
                'TMX' => $grouped[$fcstDate]['tmx'] = (int) $value,
                'SKY' => $grouped[$fcstDate]['sky'] ??= (int) $value,
                'PTY' => $grouped[$fcstDate]['pty'] ??= (int) $value,
                default => null,
            };
        }

        // 아이콘 매핑
        $result = [];
        foreach ($grouped as $date => $data) {
            $result[$date] = [
                'date' => $date,
                'tmn' => $data['tmn'],
                'tmx' => $data['tmx'],
                'icon' => $this->shortWeatherToIcon($data['sky'] ?? 1, $data['pty'] ?? 0),
            ];
        }

        return $result;
    }

    /**
     * 중기기온 API 호출
     */
    private function fetchMidTemperature(): array
    {
        $tmFc = $this->getMidBaseTmFc();

        $response = Http::timeout(10)->get(self::BASE_MID_TA, [
            'serviceKey' => $this->serviceKey,
            'pageNo' => 1,
            'numOfRows' => 10,
            'dataType' => 'JSON',
            'regId' => self::MID_TA_REG_ID,
            'tmFc' => $tmFc,
        ]);

        if (! $response->successful()) {
            return [];
        }

        $items = data_get($response->json(), 'response.body.items.item', []);

        return $items[0] ?? [];
    }

    /**
     * 중기날씨 API 호출
     */
    private function fetchMidLandForecast(): array
    {
        $tmFc = $this->getMidBaseTmFc();

        $response = Http::timeout(10)->get(self::BASE_MID_LAND, [
            'serviceKey' => $this->serviceKey,
            'pageNo' => 1,
            'numOfRows' => 10,
            'dataType' => 'JSON',
            'regId' => self::MID_LAND_REG_ID,
            'tmFc' => $tmFc,
        ]);

        if (! $response->successful()) {
            return [];
        }

        $items = data_get($response->json(), 'response.body.items.item', []);

        return $items[0] ?? [];
    }

    /**
     * 중기예보 발표시각 (06시/18시 기준)
     */
    private function getMidBaseTmFc(): string
    {
        $now = Carbon::now();

        if ($now->hour >= 18) {
            return $now->format('Ymd').'1800';
        } elseif ($now->hour >= 6) {
            return $now->format('Ymd').'0600';
        }

        return $now->copy()->subDay()->format('Ymd').'1800';
    }

    /**
     * 단기예보 SKY + PTY → 아이콘 이름
     * PTY 우선: 비/눈/진눈깨비가 있으면 해당 아이콘
     */
    private function shortWeatherToIcon(int $sky, int $pty): string
    {
        // PTY (강수형태) 우선
        if ($pty > 0) {
            return match ($pty) {
                1, 4 => 'rain',       // 비, 소나기
                2 => 'sleet',         // 비/눈
                3 => 'snow',          // 눈
                5 => 'rain',          // 빗방울
                6 => 'sleet',         // 빗방울/눈날림
                7 => 'snow',          // 눈날림
                default => 'cloud',
            };
        }

        // SKY (하늘상태)
        return match ($sky) {
            1 => 'sun',           // 맑음
            3 => 'cloud-sun',     // 구름많음
            4 => 'cloud',         // 흐림
            default => 'sun',
        };
    }

    /**
     * 중기예보 한글 날씨 문자열 → 아이콘 이름
     */
    private function midWeatherToIcon(string $wf): string
    {
        if (empty($wf)) {
            return 'cloud';
        }

        $wf = mb_strtolower($wf);

        if (str_contains($wf, '눈') && str_contains($wf, '비')) {
            return 'sleet';
        }
        if (str_contains($wf, '눈')) {
            return 'snow';
        }
        if (str_contains($wf, '비') || str_contains($wf, '소나기')) {
            return 'rain';
        }
        if (str_contains($wf, '흐림')) {
            return 'cloud';
        }
        if (str_contains($wf, '구름')) {
            return 'cloud-sun';
        }
        if (str_contains($wf, '맑음')) {
            return 'sun';
        }

        return 'cloud';
    }
}