<?php

namespace App\Services\Currency;

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

class CurrencyConverterService
{
    private const CACHE_KEY = 'currency:usd_to_ghs';
    private const CACHE_KEY_EUR = 'currency:eur_to_ghs';
    private const CACHE_TTL_MINUTES = 60;
    private const FALLBACK_RATE = 15.50;
    private const FALLBACK_EUR_RATE = 16.90;

    public function getUsdToGhsRate(): float
    {
        return Cache::remember(self::CACHE_KEY, now()->addMinutes(self::CACHE_TTL_MINUTES), function () {
            return $this->fetchRateFromBase('USD') ?? self::FALLBACK_RATE;
        });
    }

    public function getEurToGhsRate(): float
    {
        return Cache::remember(self::CACHE_KEY_EUR, now()->addMinutes(self::CACHE_TTL_MINUTES), function () {
            return $this->fetchRateFromBase('EUR') ?? self::FALLBACK_EUR_RATE;
        });
    }

    /**
     * Convert USD amount to GHS.
     */
    public function convertUsdToGhs(float $usdAmount): float
    {
        return $usdAmount * $this->getUsdToGhsRate();
    }

    /**
     * Convert USD to GHS with markup percentage.
     */
    public function convertWithMarkup(float $usdAmount, float $markupPercent = 35): float
    {
        $ghsAmount = $this->convertUsdToGhs($usdAmount);
        return $ghsAmount * (1 + ($markupPercent / 100));
    }

    /**
     * Convert USD cents to GHS pesewas with markup.
     */
    public function convertCentsTopesewaswithMarkup(int $usdCents, float $markupPercent = 35): int
    {
        $usdAmount = $usdCents / 100;
        $ghsAmount = $this->convertWithMarkup($usdAmount, $markupPercent);
        return (int) round($ghsAmount * 100);
    }

    private function fetchRateFromBase(string $base): ?float
    {
        $rate = $this->fetchFromExchangeRateApi($base)
            ?? $this->fetchFromFreeCurrencyApi($base)
            ?? $this->fetchFromOpenExchangeRates($base);

        if ($rate !== null) {
            Log::info('Currency rate fetched', ['base' => $base, 'ghs' => $rate]);
        }

        return $rate;
    }

    private function fetchFromExchangeRateApi(string $base): ?float
    {
        try {
            $response = Http::timeout(5)->get("https://api.exchangerate-api.com/v4/latest/{$base}");

            if ($response->successful()) {
                $data = $response->json();
                return (float) ($data['rates']['GHS'] ?? null) ?: null;
            }
        } catch (\Throwable $e) {
            Log::warning('ExchangeRateApi fetch failed', ['base' => $base, 'error' => $e->getMessage()]);
        }

        return null;
    }

    private function fetchFromFreeCurrencyApi(string $base): ?float
    {
        $apiKey = config('services.freecurrencyapi.key');

        if (empty($apiKey)) {
            return null;
        }

        try {
            $response = Http::timeout(5)->get('https://api.freecurrencyapi.com/v1/latest', [
                'apikey' => $apiKey,
                'base_currency' => $base,
                'currencies' => 'GHS',
            ]);

            if ($response->successful()) {
                $data = $response->json();
                return (float) ($data['data']['GHS'] ?? null) ?: null;
            }
        } catch (\Throwable $e) {
            Log::warning('FreeCurrencyApi fetch failed', ['base' => $base, 'error' => $e->getMessage()]);
        }

        return null;
    }

    private function fetchFromOpenExchangeRates(string $base): ?float
    {
        $appId = config('services.openexchangerates.app_id');

        if (empty($appId)) {
            return null;
        }

        // Free tier only supports USD as base
        if ($base !== 'USD') {
            return null;
        }

        try {
            $response = Http::timeout(5)->get('https://openexchangerates.org/api/latest.json', [
                'app_id' => $appId,
                'symbols' => 'GHS',
            ]);

            if ($response->successful()) {
                $data = $response->json();
                return (float) ($data['rates']['GHS'] ?? null) ?: null;
            }
        } catch (\Throwable $e) {
            Log::warning('OpenExchangeRates fetch failed', ['base' => $base, 'error' => $e->getMessage()]);
        }

        return null;
    }

    /**
     * Force refresh the cached rate.
     */
    public function refreshRate(): float
    {
        Cache::forget(self::CACHE_KEY);
        Cache::forget(self::CACHE_KEY_EUR);
        return $this->getUsdToGhsRate();
    }

    /**
     * Get the current cached rate info.
     */
    public function getRateInfo(): array
    {
        return [
            'rate' => $this->getUsdToGhsRate(),
            'from' => 'USD',
            'to' => 'GHS',
            'cached' => Cache::has(self::CACHE_KEY),
            'fallback' => self::FALLBACK_RATE,
        ];
    }
}