<?php

namespace Modules\Accounting\Services;

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

class ExternalExchangeRateProvider
{
    protected int $timeout;

    public function __construct()
    {
        $this->timeout = (int) config('accounting.fx_api.timeout', 15);
    }

    /**
     * @param  array<int, string>  $currencies
     * @return array<string, float> currency => rate (1 unit of currency = X base)
     */
    public function fetchRatesToBase(string $baseCurrency, array $currencies, ?string $provider = null, ?string $apiKey = null): array
    {
        $base = strtoupper($baseCurrency);
        $payload = $this->fetchPayload($base, $provider, $apiKey);

        if (empty($payload['rates']) || empty($payload['base'])) {
            return [];
        }

        $apiBase = strtoupper((string) $payload['base']);
        $apiRates = $payload['rates'];
        $result = [];

        foreach ($currencies as $currency) {
            $currency = strtoupper($currency);

            if ($currency === $base) {
                continue;
            }

            $rate = $this->convertToBaseRate($currency, $base, $apiBase, $apiRates);
            if ($rate !== null && $rate > 0) {
                $result[$currency] = $rate;
            }
        }

        return $result;
    }

    protected function fetchPayload(string $baseCurrency, ?string $provider, ?string $apiKey): array
    {
        $provider = $provider ?: config('accounting.fx_api.default_provider', 'open_er_api');

        try {
            if ($provider === 'exchangerate_api_v6') {
                if (empty($apiKey)) {
                    return [];
                }

                $url = 'https://v6.exchangerate-api.com/v6/'.$apiKey.'/latest/'.$baseCurrency;
                $response = Http::timeout($this->timeout)->get($url);

                if (! $response->successful()) {
                    Log::warning('FX API v6 failed', ['status' => $response->status(), 'body' => $response->body()]);

                    return [];
                }

                $json = $response->json();

                return [
                    'base' => data_get($json, 'base_code', $baseCurrency),
                    'rates' => (array) data_get($json, 'conversion_rates', []),
                ];
            }

            if ($provider === 'iran_market' || $provider === 'cbi_ir') {
                return $this->fetchIranMarketPayload();
            }

            if ($provider === 'exchangerate_api_v4') {
                $url = 'https://api.exchangerate-api.com/v4/latest/'.$baseCurrency;
                $response = Http::timeout($this->timeout)->get($url);

                if (! $response->successful()) {
                    Log::warning('FX API v4 failed', ['status' => $response->status()]);

                    return [];
                }

                $json = $response->json();

                return [
                    'base' => data_get($json, 'base', $baseCurrency),
                    'rates' => (array) data_get($json, 'rates', []),
                ];
            }

            $url = 'https://open.er-api.com/v6/latest/'.$baseCurrency;
            $response = Http::timeout($this->timeout)->get($url);

            if (! $response->successful()) {
                Log::warning('open.er-api failed', ['status' => $response->status()]);

                return [];
            }

            $json = $response->json();
            if (data_get($json, 'result') !== 'success') {
                return [];
            }

            return [
                'base' => data_get($json, 'base_code', $baseCurrency),
                'rates' => (array) data_get($json, 'rates', []),
            ];
        } catch (\Throwable $e) {
            Log::error('FX API request failed: '.$e->getMessage());

            return [];
        }
    }

    /**
     * @param  array<string, float>  $apiRates
     */
    protected function convertToBaseRate(string $currency, string $targetBase, string $apiBase, array $apiRates): ?float
    {
        if ($apiBase === $targetBase) {
            if (empty($apiRates[$currency])) {
                return null;
            }

            return 1 / (float) $apiRates[$currency];
        }

        if (empty($apiRates[$currency]) || empty($apiRates[$targetBase])) {
            return null;
        }

        return (float) $apiRates[$targetBase] / (float) $apiRates[$currency];
    }

    protected function fetchIranMarketPayload(): array
    {
        $response = Http::timeout($this->timeout)
            ->withHeaders(['User-Agent' => 'UltimatePOS-Accounting/1.0'])
            ->get('https://call2.tgju.org/ajax.json');

        if (! $response->successful()) {
            Log::warning('Iran market FX API failed', ['status' => $response->status()]);

            return [];
        }

        $current = (array) data_get($response->json(), 'current', []);
        $map = [
            'USD' => 'price_dollar_rl',
            'EUR' => 'price_euro',
            'GBP' => 'price_gbp',
            'AED' => 'price_derham',
        ];

        $rates = [];
        foreach ($map as $code => $key) {
            $raw = data_get($current, $key.'.p');
            if (empty($raw)) {
                continue;
            }

            $priceInIrr = (float) str_replace([',', ' '], '', (string) $raw);
            if ($priceInIrr > 0) {
                $rates[$code] = 1 / $priceInIrr;
            }
        }

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

        return [
            'base' => 'IRR',
            'rates' => $rates,
        ];
    }

    /**
     * @return array{market: array<string, float>, official: array<string, float>}
     */
    public function fetchIranDualRates(): array
    {
        $response = Http::timeout($this->timeout)
            ->withHeaders(['User-Agent' => 'UltimatePOS-Accounting/1.0'])
            ->get('https://call2.tgju.org/ajax.json');

        if (! $response->successful()) {
            return ['market' => [], 'official' => []];
        }

        $current = (array) data_get($response->json(), 'current', []);
        $marketMap = [
            'USD' => 'price_dollar_rl',
            'EUR' => 'price_euro',
            'GBP' => 'price_gbp',
            'AED' => 'price_derham',
        ];
        $officialMap = [
            'USD' => 'sana_dollar_rl',
            'EUR' => 'sana_euro',
            'GBP' => 'sana_gbp',
            'AED' => 'sana_derham',
        ];

        return [
            'market' => $this->parseIranPriceMap($current, $marketMap),
            'official' => $this->parseIranPriceMap($current, $officialMap),
        ];
    }

    /**
     * @param  array<string, string>  $map
     * @return array<string, float>
     */
    protected function parseIranPriceMap(array $current, array $map): array
    {
        $rates = [];
        foreach ($map as $code => $key) {
            $raw = data_get($current, $key.'.p');
            if (empty($raw)) {
                continue;
            }

            $priceInIrr = (float) str_replace([',', ' '], '', (string) $raw);
            if ($priceInIrr > 0) {
                $rates[$code] = $priceInIrr;
            }
        }

        return $rates;
    }
}